---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Mon 06/10/13: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:01 AM - clearing oil from the M 14 V (Richard Goode) 2. 08:13 AM - Cory Pobin (Joe Howse) 3. 09:40 AM - Re: clearing oil from the M 14 V (Elmar & Manuela Hegenauer) 4. 10:07 AM - Stall warning indicator switch. (Bradly Banks) 5. 10:07 AM - Stall warning indicator switch. (Bradly Banks) 6. 11:20 AM - Re: Air system 'stuff' (Bitterlich, Mark G CIV NAVAIR, WD) 7. 11:43 AM - New Subject: Landing Gear Operation on a YAK-50 (LONG) (Bitterlich, Mark G CIV NAVAIR, WD) 8. 11:46 AM - Re: Air system 'stuff' (doug sapp) 9. 11:55 AM - Stall warning switch (George Coy) 10. 12:02 PM - Re: New Subject: Landing Gear Operation on a YAK-50 (LONG) (Roger Kemp) 11. 12:15 PM - Re: Air system 'stuff' (Bitterlich, Mark G CIV NAVAIR, WD) 12. 01:37 PM - Stall warning indicator switch. (Bradly Banks) 13. 02:15 PM - Re: Air system 'stuff' (Roger Kemp M.D.) 14. 02:43 PM - Re: Air system 'stuff' (doug sapp) 15. 04:06 PM - Re: Air system 'stuff' (Robin Hou) ________________________________ Message 1 _____________________________________ Time: 03:01:39 AM PST US From: "Richard Goode" Subject: Yak-List: clearing oil from the M 14 V In reply to the question as to how oil is cleared from the cylinders of the M 14 V helicopter engine, as mounted in the Kamov - 26 - the engineer climbs up on a platform, and inserts a crank handle into the side of the engine and turns it like that. But not so easy for a private owner. Interestingly I spent some time with Mil in Moscow, looking at their excellent, and very aerobatic, Mil-34 helicopter, powered by the same engine. They were then planning to sell significant quantities to the West, and it had a similar crank handle to rotate the engine before starting. I asked their guys where the crank handle was put in the aeroplane touring flight, since clearly you needed to take it with you, but they said that it was not necessary because there was always one at the airfield where you landed. The idea that you would use your helicopter to land at your friends house, or somewhere well away from an airfield simply didn't enter their minds! Richard Goode Aerobatics Rhodds Farm Lyonshall Hereford HR5 3LW Tel: +44 (0) 1544 340120 Fax: +44 (0) 1544 340129 www.russianaeros.com ________________________________ Message 2 _____________________________________ Time: 08:13:25 AM PST US From: "Joe Howse" Subject: Yak-List: Cory Pobin Cory The air control valves you found, were they the AD50 as used in the Yak 18T? Joe ________________________________ Message 3 _____________________________________ Time: 09:40:17 AM PST US From: Elmar & Manuela Hegenauer Subject: Yak-List: RE: clearing oil from the M 14 V Hi Richard, thank you for bringing some light into that mystery, much appreciated. Can you imagine the size of that crank handle, must be quite impressive. The Russians seem to have simple solutions for almost everything, they might even have invented the KISS principle - who knows? Thank you again and have a good week. cheers Elmar ________________________________ Message 4 _____________________________________ Time: 10:07:24 AM PST US Subject: Yak-List: Stall warning indicator switch. From: Bradly Banks SGVsbG8gYWdhaW4gYWxsLCBUb2RheSBJJ20gaG9waW5nIHRvIHRyYWNrIGRvd24gYSBzdXBwbGll ciBvZiBzdGFsbCB3YXJuaW5nIGluZGljYXRvciBzd2l0Y2hlcyBmb3IgYm90aCB0aGUgMTggdCBh bmQgdGhlIDUyLgpBbnkgaWRlYXMgb24gdGhlIHN1YmplY3QuwqAKVGhhbmtzCkJyYWQgQmFua3MK CgoKClNlbnQgZnJvbSBTYW1zdW5nIE1vYmlsZQ= ________________________________ Message 5 _____________________________________ Time: 10:07:27 AM PST US Subject: Yak-List: Stall warning indicator switch. From: Bradly Banks SGVsbG8gYWdhaW4gYWxsLCBUb2RheSBJJ20gaG9waW5nIHRvIHRyYWNrIGRvd24gYSBzdXBwbGll ciBvZiBzdGFsbCB3YXJuaW5nIGluZGljYXRvciBzd2l0Y2hlcyBmb3IgYm90aCB0aGUgMTggdCBh bmQgdGhlIDUyLgpBbnkgaWRlYXMgb24gdGhlIHN1YmplY3QuwqAKVGhhbmtzCkJyYWQgQmFua3MK CgoKClNlbnQgZnJvbSBTYW1zdW5nIE1vYmlsZQ= ________________________________ Message 6 _____________________________________ Time: 11:20:45 AM PST US Subject: RE: Yak-List: Air system 'stuff' From: "Bitterlich, Mark G CIV NAVAIR, WD" Cory, Sorry to disagree, but just in the details. The valves that you referenced are indeed pop-off valves. They open to release or by-pass pressure to keep at a maintained value, exactly as does the pressure relief valve that is in there now. That said, they are of much better design and should work much better than the ones that are in there now, if you get one rated for the pressure and flow for our application. Taken from the company's web site: "Although this valve operates very similar to a relief valve which is usually designed to release pressure quickly as soon as the set pressure is exceeded , this valve is designed to relieve pressure more gradually with changes in flow resulting in fewer pressure spikes when the valve opens and closes. This is a direct-acting valve with an adjustable spring operating against a piston subjected to the inlet pressure of the valve. Increasing the spring compression will increase the system or line pressure to be maintained. Reducing the spring compression will reduce the system or line pressure to be maintained. " The summation: "An increase in system pressure beyond the set point will cause the main valve to open and relieve or bypass the excess pressure." This is EXACTLY how our present valves work, but these are easier to get and maintain. Mark p.s. Probably a darn good replacement. -----Original Message----- From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Cory Robin Sent: Sunday, June 09, 2013 10:09 Subject: Re: Yak-List: Air system 'stuff' I found a source of a back pressure relief valve. Rather than it popping off and reducing the pressure, it maintains the pressure at your pre-set value. I've ordered a couple to test them. https://straval.com/catlist-back-pressure-regulators/back-pressure-regulator-piston-angle-valve-threaded-bps-05 ________________________________ Message 7 _____________________________________ Time: 11:43:42 AM PST US Subject: Yak-List: New Subject: Landing Gear Operation on a YAK-50 (LONG) From: "Bitterlich, Mark G CIV NAVAIR, WD" Doc LONG answer, Shortly after I purchased my YAK-50 over 13 years ago, I had the chevron seals in one actuator fail. Without help from the YAK List (not sure it even existed back then), and without help from any manuals, I disassembled that whole mess and step by step figured out how it all worked. Landing gear legs laying on the hangar floor, actuators taking apart on work benches, landing gear selector valve removed and taken apart. Every single piece examined bit by bit, every air line traced out from source to destination. I wrote a few articles covering that experience, and some of them were "copied" and made into much better presentations. From all this, I learned how the landing gear system worked, including just how important those up-lock springs are! I'm just saying it was not luck that allowed me to ferry that YAK-50 across the country with a known air leak problem, it was knowledge and experience on how the system worked that allowed me to apply a technique properly to achieve a desired solution. This is the knowledge I am trying to pass on via this topic of conversation. One of the problems with the YAK-50 is that the green "Down and Locked" Landing Gear Indicator lights can easily be behind your knee if you are relatively tall in stature. In other words, you have to consciously move your leg to look at both of them. It dawns on me that it might be a smart idea to move them up into your direct line of sight! You mentioned hearing the gear, and that it sounded normal. This is an easy habit to get into.... since I have done the exact same thing, and it's a BAD habit (IMHO). Since some history with one gear being down and not locked, I will never EVER again fail to FOCUS on BOTH of those darn lights! Needless to say, I doubt you will either. I am sure you placed the landing gear handle down. I am sure there was enough air in the system to release both gear legs from the up-locks and start them on their way down. At some point in that process, the air ran out.. for whatever reason..... or was not flowing with enough volume to force the gear forward into the air-stream to where the mechanical down-locks would then engage. The gear down and lock lights were probably not illuminated. You landed, the gear was not locked and back up they both went. I might as well tell a similar story of woe, since it will reinforce the lesson that you have offered. In this case, an A&P/AI mechanic felt that the left gear leg had too much lateral play. He tightened the attach bolt to take out the play. Shims were suggested. he said B/S to that, and that the nut just needed to be tightened. Well, the gear swung perfectly in the hangar when tested. "See?" he says. On the first flight following the Conditional, on a wheel landing, the left gear collapsed, the aircraft wing came down mighty close to the runway and the aircraft veered to the left. Full power, jammed right rudder and it goes airborne again. In the pattern, the right green down and locked light was on. The left one was not. Emergency air was applied and the left green down and locked light came on. After landing safely, it was noticed that about 4-6 inches had been ground off each end of the prop. It had flown around the pattern like that. The tower was called and told of possible FOD on the active. The security truck went out and collected a sandwich bag full of very small splinters of painted wood, with the comment: "This is all we could find". End of story: Following a complete inspection of the engine, readjustment of the landing gear attach bolt nut to where it was before, and the aircraft has since flown 300 hours since without incident. As regards your prop strike.... I am sure you have read what people far more expert than myself have said about it, but I will say that you've got a pretty good expert close to you in the form of Dennis Savarese. That said: Make sure you very carefully and very exactly check the timing on the mags. Not to each other, but to the timing they should be, using the piston position, safety wire to dial method. If the timing is off *AT ALL*, then the accessory shaft has twisted and you are looking at a mandatory tear down. If the engine timing is OK, I would be tempted to have the planetary gear box inspected and if that checks good then I would be inclined to light her off and check her out. Others may not agree, and I have no dog in this fight per se. Only the person that was there when it happened can make a true and honest evaluation of how bad it really was. I don't have a clue why oil is seeping from your carb throat. Someone else needs to discuss that one! I am not a hydraulic line expert... but I am not totally ignorant of them either. I would not replace all lines with braided Aeroquip (not sure if that was what you were suggesting or not). If you are going to re-plumb the aircraft, use rigid lines where rigid lines originally were, and flexible lines, where flexible lines originally were. The aluminum lines used on the YAK's are very VERY pure aluminum (I've had them tested), but that also means they are rather soft as compared to what is typically used in the West. Be careful of changing the design of any air line that "moves". Putting in braided Aeroquip puts additional load on fittings they attach to, if that line "moves" during intended operation. So you could end up "fixing" the line, and then snapping off a fitting. It is wise to approach "re-design" very carefully. For example, I would guess most everyone would think that the engine cooling shutters are there to control airflow over the engine. They are, and that's true... but they *ALSO* provide mounting strength and stability to the front of the upper and lower engine cowls. A good thing to know if you are tempted to replace the original shutter design with a Sukhoi type IRIS. Good luck Doc, I my heart goes out to you and I hope the rebuild is not too bad. Mark -----Original Message----- From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp M.D. Sent: Sunday, June 09, 2013 11:02 Subject: Re: Yak-List: Air system 'stuff' --> Mark, I honestly do not remember if I saw green. I do remember hearing the sound of the gear lowering and remember feeling a thump. I thought I did but my lights are dimmer in the 50 than the 52. As I turned base final I looked at the gear handle, then slipped the AC to watch the 195 back taxi off the grass runway with me on final. I was trying to decide if I was going around for a second time. That was the same guy that said he saw my gear down however. Then there was the Jahova's Witness that stopped on airport road to watch the "fighter" land with his son before he turned into the drive way for the "Freedom Hall" across the street. He did not see the touchdown but did see the plane after it was sliding along on it's nose. He said my gear was down but thought one looked "a little funny". Whatever that meant. I'll remember that could never happen if I ever have another WTFO moment like this again since you were lucky enough to ferry a 50 across the US with a known air leak without any problem. So I won't worry about the brittle looking aluminum partially crimped air line that goes from the main air bottle to the T fitting for what looks like the actuator lines fittings in the fuselage on the front of the spar box as they disappear into a hole in the bulkhead. Found that using my fiber optic bore scope Sat. Can not pull the tanks out yet because the insurance company has not made a decision. Got to replace or repair the AUX tank since it has developed a crack and a leak also since the slide on the grass. Trust me, I'll be replacing those lines that appear to have been there for a long time. I am replacing them with braided Aeroquip lines. There is a long list of "I wills" that will be done concerning the air and gear systems before Red Nose is returned to service. Who knows, the gear may fold inward and flush with the wing root before I'm done. I've already taken care of that wart on the chin by crushing the oil cooler flush with the fuselage. Do I need to worry about the oil leaking out of the carb throat or can I just replace the shattered blades, light her off, and go fly? May smoke a little more for a short time though. The engine was at dead idle after all. Tongue and cheek ... Wink... Wink. Doc Sent from my iPad On Jun 8, 2013, at 11:17 AM, "Bitterlich, Mark G CIV NAVAIR, WD" wrote: > --> > > Doc, > > The 74, 78 80 and 85 are identical when it comes to air system design > and landing gear operation. Some of the parts are different, but the > design and operation are the same. What are you talking about "the > gear is beefier"? Where are you getting this information? I am > talking YAK-50's here ok? You are passing unsupported assertions. > Give me the different part numbers you are talking about. Example, my > YAK-50 has Cleveland wheels and hyd. Toe brakes. That does not mean > the factory put that stuff there! > > Regarding springs, a lot of them have been changed over the years as > they have rusted out. Springs are very critical. I think you are > assuming that since you see different parts on different 50's that the > factory used different parts. Realize that these aircraft have gone > through many owners and locations. A lot of mechs have changed parts > from stock. Most especially springs. > > The only change in the fuel system was adding the Aux Tank. > > We are not talking about YAK-18A's, and we are not talking about CJ6's. > We are talking about YAK-50's. Please stop misdirecting the discussion. > > > As regards the string of events that lead to an accident, yours or > anyone else's, you are absolutely correct. But I am not trying to > discuss that chain of events. > > If you are telling me you DID check BOTH GREEN LIGHTS ON showing "down > and locked" and then you tell me that BOTH gear then collapsed after > landing due to some kind of air leak, that is just next to impossible. > You would have to have had BOTH landing gear switches out of rig. One > of them being slightly misadjusted, I could believe is possible. Both > of them being out of adjustment the exact same way, to the exact same > degree... the odds are next to impossible. > > Loss of air pressure due to WHATEVER reason... actuators, broken > lines, broken chevron seals, main air valve not open, WHATEVER... can > indeed caused the gear to not come down and lock. The gear can be > released from the uplocks if there is ANY residual air pressure. It > will then come down and kind of HANG there. It will not lock and you > will not have both DOWN AND LOCKED green lights come on. This is > probably what happened to you. Something similar happened to me when > my left gear was not down and locked because the attach bolt had been over-tightened... > main gear leg attach bolt. But that is also "another story". > > Regardless. Once a YAK-50 landing gear is down and locked, loss of > air pressure will not cause it to collapse... .and that statement applies to > every YAK-50 ever made. > > The reason I am posting this in public is because you are giving the > impression to folks that this is not true. That loss of air pressure > after the gear is down and locked CAN cause the gear to collapse after > landing. I'm sorry, but leaving that kind of misinformation as truth > has to be corrected. > > Loss of air pressure after the landing gear is down and locked on a > YAK-50 will never cause the landing gear to collapse. > > Mark Bitterlich > > > > > -----Original Message----- > From: owner-yak-list-server@matronics.com > [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp > M.D. > Sent: Friday, June 07, 2013 22:54 > To: yak-list@matronics.com > Subject: Re: Yak-List: Air system 'stuff' > > --> > > Don't know Mark. To use a famous quote, " It just went blew!" Is the > 74 the same as the 78 as the 80 as the 85? No. The gear is beefier on > the > 85 than the 78 for one. My mechanical lock spring is not as hefty as > the 85's either. The fuel system is different also. I know that from > crawling around on the 85 sitting in the back of my hanger. The 85 has > better lateral stability than than the 78 slick wing that I have...had. > The 78's actuator as you say does not have the ball check valve. It > uses air to push and pull applied at either end of the actuator. As I > said my spring is smaller than that on the 85. And all I can tell for > a heart beat there I saw a wind screen full of green as the nose went > down. One blade is shorter than the other as well as it sheered off > just inside the cowl diameter and I have dirt up in my hub. > The CJ nose strut actuator will work on the 78 is another difference. > The CJ actuator is the same as the YAK 18A's. I don't know if they > will work on the later model 50's. > One of my air lines has 04 on it and the other has 02 on it. The lines > to the actuators have faded enough that I can not read them. So again > this was my error in not replacing them sooner. > I can tell you all incidents or accidents start as a series of small > events that lead up the big event. Just need to break the cycle to > prevent the incident. I did not catch the series. If I had listened to > that little internal voice that said taxi into your ramp and shut down > as I taxied by after fueling up we would not be having this > conversation. If I had not been pressed to beat a TFR, we would not be > having this conversation. If I had not checked the main air valve > before TO, we would not be having this conversation. If weather had > not become a factor in route going from marginal VFR to IFR resulting > in my turning back, we would not be having this conversation. But then > again had I landed on concrete instead of grass I may not have been > here any longer and we would not be having this conversation for sure. > If I had squeezed the brake handle and release it before turning the > air on to start after priming we would not be having this conversation. > Hide sight is always 20/20 as are arm chair quarterbacks. > Doc > > Sent from my iPad > > On Jun 7, 2013, at 2:00 PM, "Bitterlich, Mark G CIV NAVAIR, WD" > wrote: > >> --> >> >> Doc, you said that you wished you had caught the airline leak at the > manifold for the actuators before the landing gear collapsed. >> >> I'm kind of confused by that statement, and it brings up an important > point. The YAK-52 (I say again YAK-52!!) uses an internal ball lock > assembly internal to the actuators. If those are in bad shape and you > lose pressure to the landing gear ..... the gear can collapse. I've > seen it happen three times on one YA-52 before the owner finally got > the actuators repaired. >> >> However, the YAK-50 (I say again YAK-50) does not work like that. It > uses an EXTERNAL LOCKING device that is purely mechanical in nature. > Once the landing gear comes down, you can remove all pressure from the > pneumatic system and land safely with no possibility of the gear > collapsing. In fact that is a good safety procedure for every YAK-50 > owner to know, which is why I am writing this. If you can get the > gear down on a YAK-50 that has an internal air leak, you can then > place the gear handle back into the MIDDLE position, which isolates > pneumatic pressure from the landing gear system, and allows the engine > air compressor to pump back up to 50 atmos on BOTH the main and > emergency bottle. This then allows you to land with full pressure > available to the BRAKES! I flew a YAK-50 almost all the way from the > east coast to Ramona California that way (for Vladimir Yastremski). > It had a bad air leak when the gear went down, enough so that I would > have had to land with no brak! > es! >> available. This method is not documented, but trust me when I say I > am 100% sure of how this works. It could be considered an Emergency > Procedure. >> >> Moving on, I would assume that during every Conditional Inspection on > your aircraft, you swing the gear. Part of that inspection is to make > sure that the landing gear lights do not show down and locked BEFORE > the landing gear is actually DOWN AND LOCKED! I.E. You don't want to > have the gear lights indicate it is down, when it is actually NOT > down. This requires the landing gear to be lowered very slowly with a > steady hand on the master air valve, while one person watches the > lights and another person watches the external locking block snap into place. >> >> So assuming that your landing gear indication switches were properly > adjusted, then any kind of airline leak ANYWHERE in the system would > not cause the gear to collapse once it indicated down and locked. >> >> What this means is that if your gear collapsed upon or after landing, > then they were never down and locked to begin with and you probably > missed the fact that both green lights were not lit, or you heard what > you thought were normal sounds and assumed the gear was down. It's an > easy mistake to make, and I personally believe I made the same mistake > myself! >> >> An air leak can cause enough pressure loss to keep the gear from > coming down and locking... but if that were the case, there would be > no air left in the main and emergency bottle, because you would have > blown the gear with the emergency valve. >> >> But if the gear was down and locked and indicating same ... you only > have two possibilities. >> >> 1. The landing gear indicators were totally mis-rigged *AND* you had > an air leak preventing total gear extension, in which case you should > shoot your A&P mechanic for not inspecting the landing gear switches > properly. >> >> 2. The landing gear was never down and locked to begin with. >> >> Once the gear is down and locked, it does not need air to keep it >> down > and locked. Just the way it works Doc, so you may need to rethink > what happened. >> >> Mark >> >> >> >> >> >> -----Original Message----- >> From: owner-yak-list-server@matronics.com >> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp >> Sent: Thursday, June 06, 2013 16:15 >> To: yak-list@matronics.com >> Subject: Re: Yak-List: Air system 'stuff' >> >> >> Speaking for the 78 model 50, the internal components are not the >> same > YAK vs the CJ. It is easy to swap the entire check valve assembly out > though. That is what I did on the 50. Solved the leaking check valve > at the pop off problem in about 4 hours. Just wish I had caught the > airline leak at the manifold for the acutators before the gear > collapsed. Would have saved a lot of headaches! >> Doc >> >> -----Original Message----- >>> From: "A. Dennis Savarese" >>> Sent: Jun 6, 2013 1:44 PM >>> To: yak-list@matronics.com >>> Subject: Re: Yak-List: Air system 'stuff' >>> >>> --> >>> >>> The Yak 50 pop off valve internal components may be interchangeable >>> with the Chinese components. But definitely not the Yak 52. >>> Dennis >>> >>> A. Dennis Savarese >>> 334-285-6263 >>> 334-546-8182 (mobile) >>> www.yak-52.com >>> Skype - Yakguy1 >>> >>> On 6/6/2013 1:18 PM, A. Dennis Savarese wrote: >>>> >>>> >>>> Unfortunately, the CJ6's pressure relief valve or pop off valve's >>>> internal components are not the same as the one on the 52. The >>>> pistons are not interchangeable. >>>> >>>> If you need a new piston for a Yak 52 pop off valve, I believe Jill >>>> has them and so does Cliff Coy at Border Air. The spring for the >>>> 52's pop off valve may be a little harder to find. But Jill or >>>> Cliff can help with that. >>>> >>>> We have converted a few Yak 52's to the CJ6 pop off valve assembly >>>> with the two Chinese check valves because the Chinese check valves >>>> are significantly less expensive and Doug typically has them or > overhaul >>>> kits in stock. (Thank you Doug). The Russian check valves are > VERY >>>> expensive, IF you can find them. >>>> >>>> Dennis >>>> >>>> A. Dennis Savarese >>>> 334-285-6263 >>>> 334-546-8182 (mobile) >>>> www.yak-52.com >>>> Skype - Yakguy1 >>>> >>>> On 6/6/2013 11:34 AM, Bitterlich, Mark G CIV NAVAIR, WD wrote: WD" > >>>>> >>>>> >>>>> Just FYI. >>>>> >>>>> The CJ6 valve ASSEMBLY that Doug has, is not always a direct >>>>> replacement for every YAK pressure relief valve. Slightly >>>>> different fittings in some cases. >>>>> >>>>> But the answer is obvious. If you take apart HIS valve and remove >>>>> the sealing piston, spring and screw on pressure adjusting top >>>>> piece, and put them on yours, they fit perfectly and will work > perfectly. >>>>> >>>>> You will then have to reset your maximum pressure. Be careful. >>>>> >>>>> Mark Bitterlich >>>>> >>>>> >>>>> -----Original Message----- >>>>> From: owner-yak-list-server@matronics.com >>>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Cory >>>>> Robin >>>>> Sent: Thursday, June 06, 2013 1:00 >>>>> To: yak-list@matronics.com >>>>> Subject: Re: Yak-List: Air system 'stuff' >>>>> >>>>> Thank you all. I contacted Doug and have a valve on it's way. >> >> >> >> >> >> >> >> >> >> > > > > > > > > > > ________________________________ Message 8 _____________________________________ Time: 11:46:09 AM PST US Subject: Re: Yak-List: Air system 'stuff' From: doug sapp Cory, Mark is correct in all he said, however the valve which you have selected would be somewhat prone to problems if your upstream air system is not 100% free of foreign material, such as old std steel rusted spring parts, dirt, grease, etc. These valves are intended for use in clean environments, not the somewhat dirtier systems of the CJ6. Placing the valve just after a high quality filter would both extend it's life and lower the probability of reoccurring maintenance issues I'm sure. Best, Doug On Mon, Jun 10, 2013 at 11:12 AM, Bitterlich, Mark G CIV NAVAIR, WD < mark.bitterlich@navy.mil> wrote: > mark.bitterlich@navy.mil> > > Cory, > > Sorry to disagree, but just in the details. The valves that you > referenced are indeed pop-off valves. They open to release or by-pass > pressure to keep at a maintained value, exactly as does the pressure relief > valve that is in there now. That said, they are of much better design and > should work much better than the ones that are in there now, if you get one > rated for the pressure and flow for our application. > > Taken from the company's web site: > > "Although this valve operates very similar to a relief valve which is > usually designed to release pressure quickly as soon as the set pressure is > exceeded , this valve is designed to relieve pressure more gradually with > changes in flow resulting in fewer pressure spikes when the valve opens and > closes. This is a direct-acting valve with an adjustable spring operating > against a piston subjected to the inlet pressure of the valve. Increasing > the spring compression will increase the system or line pressure to be > maintained. Reducing the spring compression will reduce the system or line > pressure to be maintained. " > > The summation: > > "An increase in system pressure beyond the set point will cause the main > valve to open and relieve or bypass the excess pressure." > > This is EXACTLY how our present valves work, but these are easier to get > and maintain. > > Mark > > p.s. Probably a darn good replacement. > > > -----Original Message----- > From: owner-yak-list-server@matronics.com [mailto: > owner-yak-list-server@matronics.com] On Behalf Of Cory Robin > Sent: Sunday, June 09, 2013 10:09 > To: yak-list@matronics.com > Subject: Re: Yak-List: Air system 'stuff' > > I found a source of a back pressure relief valve. Rather than it popping > off and reducing the pressure, it maintains the pressure at your pre-set > value. > > I've ordered a couple to test them. > > > https://straval.com/catlist-back-pressure-regulators/back-pressure-regulator-piston-angle-valve-threaded-bps-05 > > ________________________________ Message 9 _____________________________________ Time: 11:55:16 AM PST US From: "George Coy" Subject: Yak-List: Stall warning switch We have a Yak 52 stall warning switch in stock. Contact off list George Coy CAS Ltd. 714 Airport Rd. Swanton VT 05488 802-868-5633 off 802-363-5782 cell 802-868-4465 Fax george.coy@gmail.com http://coyacft.com/ SKYPE george.coy ________________________________ Message 10 ____________________________________ Time: 12:02:41 PM PST US From: Roger Kemp Subject: Re: Yak-List: New Subject: Landing Gear Operation on a YAK-50 (LONG) Mark, Copy all. Thanks since I have not had the opportunity to tear down the gear but guess I am now. A learning experience!. Thanks again. Doc -----Original Message----- >From: "Bitterlich, Mark G CIV NAVAIR, WD" >Sent: Jun 10, 2013 1:41 PM >To: yak-list@matronics.com >Subject: Yak-List: New Subject: Landing Gear Operation on a YAK-50 (LONG) > > >Doc LONG answer, > >Shortly after I purchased my YAK-50 over 13 years ago, I had the chevron >seals in one actuator fail. Without help from the YAK List (not sure it >even existed back then), and without help from any manuals, I >disassembled that whole mess and step by step figured out how it all >worked. Landing gear legs laying on the hangar floor, actuators taking >apart on work benches, landing gear selector valve removed and taken >apart. Every single piece examined bit by bit, every air line traced >out from source to destination. I wrote a few articles covering that >experience, and some of them were "copied" and made into much better >presentations. From all this, I learned how the landing gear system >worked, including just how important those up-lock springs are! > >I'm just saying it was not luck that allowed me to ferry that YAK-50 >across the country with a known air leak problem, it was knowledge and >experience on how the system worked that allowed me to apply a technique >properly to achieve a desired solution. This is the knowledge I am >trying to pass on via this topic of conversation. > >One of the problems with the YAK-50 is that the green "Down and Locked" >Landing Gear Indicator lights can easily be behind your knee if you are >relatively tall in stature. In other words, you have to consciously >move your leg to look at both of them. It dawns on me that it might be a >smart idea to move them up into your direct line of sight! You >mentioned hearing the gear, and that it sounded normal. This is an easy >habit to get into.... since I have done the exact same thing, and it's a >BAD habit (IMHO). Since some history with one gear being down and not >locked, I will never EVER again fail to FOCUS on BOTH of those darn >lights! Needless to say, I doubt you will either. > >I am sure you placed the landing gear handle down. I am sure there was >enough air in the system to release both gear legs from the up-locks and >start them on their way down. At some point in that process, the air >ran out.. for whatever reason..... or was not flowing with enough volume >to force the gear forward into the air-stream to where the mechanical >down-locks would then engage. The gear down and lock lights were >probably not illuminated. You landed, the gear was not locked and back >up they both went. > >I might as well tell a similar story of woe, since it will reinforce the >lesson that you have offered. In this case, an A&P/AI mechanic felt >that the left gear leg had too much lateral play. He tightened the >attach bolt to take out the play. Shims were suggested. he said B/S to >that, and that the nut just needed to be tightened. Well, the gear >swung perfectly in the hangar when tested. "See?" he says. > >On the first flight following the Conditional, on a wheel landing, the >left gear collapsed, the aircraft wing came down mighty close to the >runway and the aircraft veered to the left. Full power, jammed right >rudder and it goes airborne again. In the pattern, the right green down >and locked light was on. The left one was not. Emergency air was >applied and the left green down and locked light came on. After landing >safely, it was noticed that about 4-6 inches had been ground off each >end of the prop. It had flown around the pattern like that. The tower >was called and told of possible FOD on the active. The security truck >went out and collected a sandwich bag full of very small splinters of >painted wood, with the comment: "This is all we could find". > >End of story: Following a complete inspection of the engine, >readjustment of the landing gear attach bolt nut to where it was before, >and the aircraft has since flown 300 hours since without incident. > >As regards your prop strike.... I am sure you have read what people far >more expert than myself have said about it, but I will say that you've >got a pretty good expert close to you in the form of Dennis Savarese. >That said: Make sure you very carefully and very exactly check the >timing on the mags. Not to each other, but to the timing they should >be, using the piston position, safety wire to dial method. If the >timing is off *AT ALL*, then the accessory shaft has twisted and you are >looking at a mandatory tear down. If the engine timing is OK, I would >be tempted to have the planetary gear box inspected and if that checks >good then I would be inclined to light her off and check her out. >Others may not agree, and I have no dog in this fight per se. Only the >person that was there when it happened can make a true and honest >evaluation of how bad it really was. I don't have a clue why oil is >seeping from your carb throat. Someone else needs to discuss that one! > > >I am not a hydraulic line expert... but I am not totally ignorant of >them either. I would not replace all lines with braided Aeroquip (not >sure if that was what you were suggesting or not). If you are going to >re-plumb the aircraft, use rigid lines where rigid lines originally >were, and flexible lines, where flexible lines originally were. The >aluminum lines used on the YAK's are very VERY pure aluminum (I've had >them tested), but that also means they are rather soft as compared to >what is typically used in the West. Be careful of changing the design >of any air line that "moves". Putting in braided Aeroquip puts >additional load on fittings they attach to, if that line "moves" during >intended operation. So you could end up "fixing" the line, and then >snapping off a fitting. > >It is wise to approach "re-design" very carefully. For example, I would >guess most everyone would think that the engine cooling shutters are >there to control airflow over the engine. They are, and that's true... >but they *ALSO* provide mounting strength and stability to the front of >the upper and lower engine cowls. A good thing to know if you are >tempted to replace the original shutter design with a Sukhoi type IRIS. > > >Good luck Doc, I my heart goes out to you and I hope the rebuild is not >too bad. > >Mark > > >-----Original Message----- >From: owner-yak-list-server@matronics.com >[mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp >M.D. >Sent: Sunday, June 09, 2013 11:02 >To: yak-list@matronics.com >Subject: Re: Yak-List: Air system 'stuff' > >--> > >Mark, >I honestly do not remember if I saw green. I do remember hearing the >sound of the gear lowering and remember feeling a thump. I thought I did >but my lights are dimmer in the 50 than the 52. As I turned base final I >looked at the gear handle, then slipped the AC to watch the 195 back >taxi off the grass runway with me on final. I was trying to decide if I >was going around for a second time. That was the same guy that said he >saw my gear down however. Then there was the Jahova's Witness that >stopped on airport road to watch the "fighter" land with his son before >he turned into the drive way for the "Freedom Hall" across the street. >He did not see the touchdown but did see the plane after it was sliding >along on it's nose. He said my gear was down but thought one looked "a >little funny". Whatever that meant. >I'll remember that could never happen if I ever have another WTFO moment >like this again since you were lucky enough to ferry a 50 across the US >with a known air leak without any problem. > >So I won't worry about the brittle looking aluminum partially crimped >air line that goes from the main air bottle to the T fitting for what >looks like the actuator lines fittings in the fuselage on the front of >the spar box as they disappear into a hole in the bulkhead. Found that >using my fiber optic bore scope Sat. Can not pull the tanks out yet >because the insurance company has not made a decision. Got to replace or >repair the AUX tank since it has developed a crack and a leak also since >the slide on the grass. >Trust me, I'll be replacing those lines that appear to have been there >for a long time. I am replacing them with braided Aeroquip lines. There >is a long list of "I wills" that will be done concerning the air and >gear systems before Red Nose is returned to service. Who knows, the gear >may fold inward and flush with the wing root before I'm done. I've >already taken care of that wart on the chin by crushing the oil cooler >flush with the fuselage. > Do I need to worry about the oil leaking out of the carb throat or can >I just replace the shattered blades, light her off, and go fly? May >smoke a little more for a short time though. >The engine was at dead idle after all. Tongue and cheek ... Wink... >Wink. >Doc > >Sent from my iPad > >On Jun 8, 2013, at 11:17 AM, "Bitterlich, Mark G CIV NAVAIR, WD" > wrote: > >> --> >> >> Doc, >> >> The 74, 78 80 and 85 are identical when it comes to air system design >> and landing gear operation. Some of the parts are different, but the >> design and operation are the same. What are you talking about "the >> gear is beefier"? Where are you getting this information? I am >> talking YAK-50's here ok? You are passing unsupported assertions. >> Give me the different part numbers you are talking about. Example, my > >> YAK-50 has Cleveland wheels and hyd. Toe brakes. That does not mean >> the factory put that stuff there! >> >> Regarding springs, a lot of them have been changed over the years as >> they have rusted out. Springs are very critical. I think you are >> assuming that since you see different parts on different 50's that the > >> factory used different parts. Realize that these aircraft have gone >> through many owners and locations. A lot of mechs have changed parts >> from stock. Most especially springs. >> >> The only change in the fuel system was adding the Aux Tank. >> >> We are not talking about YAK-18A's, and we are not talking about >CJ6's. >> We are talking about YAK-50's. Please stop misdirecting the >discussion. >> >> >> As regards the string of events that lead to an accident, yours or >> anyone else's, you are absolutely correct. But I am not trying to >> discuss that chain of events. >> >> If you are telling me you DID check BOTH GREEN LIGHTS ON showing "down > >> and locked" and then you tell me that BOTH gear then collapsed after >> landing due to some kind of air leak, that is just next to impossible. >> You would have to have had BOTH landing gear switches out of rig. One > >> of them being slightly misadjusted, I could believe is possible. Both > >> of them being out of adjustment the exact same way, to the exact same >> degree... the odds are next to impossible. >> >> Loss of air pressure due to WHATEVER reason... actuators, broken >> lines, broken chevron seals, main air valve not open, WHATEVER... can >> indeed caused the gear to not come down and lock. The gear can be >> released from the uplocks if there is ANY residual air pressure. It >> will then come down and kind of HANG there. It will not lock and you >> will not have both DOWN AND LOCKED green lights come on. This is >> probably what happened to you. Something similar happened to me when >> my left gear was not down and locked because the attach bolt had been >over-tightened... >> main gear leg attach bolt. But that is also "another story". >> >> Regardless. Once a YAK-50 landing gear is down and locked, loss of >> air pressure will not cause it to collapse... .and that statement >applies to >> every YAK-50 ever made. >> >> The reason I am posting this in public is because you are giving the >> impression to folks that this is not true. That loss of air pressure >> after the gear is down and locked CAN cause the gear to collapse after > >> landing. I'm sorry, but leaving that kind of misinformation as truth >> has to be corrected. >> >> Loss of air pressure after the landing gear is down and locked on a >> YAK-50 will never cause the landing gear to collapse. >> >> Mark Bitterlich >> >> >> >> >> -----Original Message----- >> From: owner-yak-list-server@matronics.com >> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp >> M.D. >> Sent: Friday, June 07, 2013 22:54 >> To: yak-list@matronics.com >> Subject: Re: Yak-List: Air system 'stuff' >> >> --> >> >> Don't know Mark. To use a famous quote, " It just went blew!" Is the >> 74 the same as the 78 as the 80 as the 85? No. The gear is beefier on >> the >> 85 than the 78 for one. My mechanical lock spring is not as hefty as >> the 85's either. The fuel system is different also. I know that from >> crawling around on the 85 sitting in the back of my hanger. The 85 has > >> better lateral stability than than the 78 slick wing that I >have...had. >> The 78's actuator as you say does not have the ball check valve. It >> uses air to push and pull applied at either end of the actuator. As I >> said my spring is smaller than that on the 85. And all I can tell for >> a heart beat there I saw a wind screen full of green as the nose went >> down. One blade is shorter than the other as well as it sheered off >> just inside the cowl diameter and I have dirt up in my hub. >> The CJ nose strut actuator will work on the 78 is another difference. >> The CJ actuator is the same as the YAK 18A's. I don't know if they >> will work on the later model 50's. >> One of my air lines has 04 on it and the other has 02 on it. The lines > >> to the actuators have faded enough that I can not read them. So again >> this was my error in not replacing them sooner. >> I can tell you all incidents or accidents start as a series of small >> events that lead up the big event. Just need to break the cycle to >> prevent the incident. I did not catch the series. If I had listened to > >> that little internal voice that said taxi into your ramp and shut down > >> as I taxied by after fueling up we would not be having this >> conversation. If I had not been pressed to beat a TFR, we would not be > >> having this conversation. If I had not checked the main air valve >> before TO, we would not be having this conversation. If weather had >> not become a factor in route going from marginal VFR to IFR resulting > >> in my turning back, we would not be having this conversation. But then > >> again had I landed on concrete instead of grass I may not have been >> here any longer and we would not be having this conversation for sure. > >> If I had squeezed the brake handle and release it before turning the >> air on to start after priming we would not be having this >conversation. >> Hide sight is always 20/20 as are arm chair quarterbacks. >> Doc >> >> Sent from my iPad >> >> On Jun 7, 2013, at 2:00 PM, "Bitterlich, Mark G CIV NAVAIR, WD" >> wrote: >> >>> --> >>> >>> Doc, you said that you wished you had caught the airline leak at the >> manifold for the actuators before the landing gear collapsed. >>> >>> I'm kind of confused by that statement, and it brings up an important >> point. The YAK-52 (I say again YAK-52!!) uses an internal ball lock >> assembly internal to the actuators. If those are in bad shape and you > >> lose pressure to the landing gear ..... the gear can collapse. I've >> seen it happen three times on one YA-52 before the owner finally got >> the actuators repaired. >>> >>> However, the YAK-50 (I say again YAK-50) does not work like that. It >> uses an EXTERNAL LOCKING device that is purely mechanical in nature. >> Once the landing gear comes down, you can remove all pressure from the > >> pneumatic system and land safely with no possibility of the gear >> collapsing. In fact that is a good safety procedure for every YAK-50 >> owner to know, which is why I am writing this. If you can get the >> gear down on a YAK-50 that has an internal air leak, you can then >> place the gear handle back into the MIDDLE position, which isolates >> pneumatic pressure from the landing gear system, and allows the engine > >> air compressor to pump back up to 50 atmos on BOTH the main and >> emergency bottle. This then allows you to land with full pressure >> available to the BRAKES! I flew a YAK-50 almost all the way from the >> east coast to Ramona California that way (for Vladimir Yastremski). >> It had a bad air leak when the gear went down, enough so that I would >> have had to land with no brak! >> es! >>> available. This method is not documented, but trust me when I say I >> am 100% sure of how this works. It could be considered an Emergency >> Procedure. >>> >>> Moving on, I would assume that during every Conditional Inspection on >> your aircraft, you swing the gear. Part of that inspection is to make > >> sure that the landing gear lights do not show down and locked BEFORE >> the landing gear is actually DOWN AND LOCKED! I.E. You don't want to > >> have the gear lights indicate it is down, when it is actually NOT >> down. This requires the landing gear to be lowered very slowly with a > >> steady hand on the master air valve, while one person watches the >> lights and another person watches the external locking block snap into >place. >>> >>> So assuming that your landing gear indication switches were properly >> adjusted, then any kind of airline leak ANYWHERE in the system would >> not cause the gear to collapse once it indicated down and locked. >>> >>> What this means is that if your gear collapsed upon or after landing, >> then they were never down and locked to begin with and you probably >> missed the fact that both green lights were not lit, or you heard what > >> you thought were normal sounds and assumed the gear was down. It's an > >> easy mistake to make, and I personally believe I made the same mistake > >> myself! >>> >>> An air leak can cause enough pressure loss to keep the gear from >> coming down and locking... but if that were the case, there would be >> no air left in the main and emergency bottle, because you would have >> blown the gear with the emergency valve. >>> >>> But if the gear was down and locked and indicating same ... you only >> have two possibilities. >>> >>> 1. The landing gear indicators were totally mis-rigged *AND* you had >> an air leak preventing total gear extension, in which case you should >> shoot your A&P mechanic for not inspecting the landing gear switches >> properly. >>> >>> 2. The landing gear was never down and locked to begin with. >>> >>> Once the gear is down and locked, it does not need air to keep it >>> down >> and locked. Just the way it works Doc, so you may need to rethink >> what happened. >>> >>> Mark >>> >>> >>> >>> >>> >>> -----Original Message----- >>> From: owner-yak-list-server@matronics.com >>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp >>> Sent: Thursday, June 06, 2013 16:15 >>> To: yak-list@matronics.com >>> Subject: Re: Yak-List: Air system 'stuff' >>> >>> >>> Speaking for the 78 model 50, the internal components are not the >>> same >> YAK vs the CJ. It is easy to swap the entire check valve assembly out >> though. That is what I did on the 50. Solved the leaking check valve >> at the pop off problem in about 4 hours. Just wish I had caught the >> airline leak at the manifold for the acutators before the gear >> collapsed. Would have saved a lot of headaches! >>> Doc >>> >>> -----Original Message----- >>>> From: "A. Dennis Savarese" >>>> Sent: Jun 6, 2013 1:44 PM >>>> To: yak-list@matronics.com >>>> Subject: Re: Yak-List: Air system 'stuff' >>>> >>>> --> >>>> >>>> The Yak 50 pop off valve internal components may be interchangeable >>>> with the Chinese components. But definitely not the Yak 52. >>>> Dennis >>>> >>>> A. Dennis Savarese >>>> 334-285-6263 >>>> 334-546-8182 (mobile) >>>> www.yak-52.com >>>> Skype - Yakguy1 >>>> >>>> On 6/6/2013 1:18 PM, A. Dennis Savarese wrote: >>>>> >>>>> >>>>> Unfortunately, the CJ6's pressure relief valve or pop off valve's >>>>> internal components are not the same as the one on the 52. The >>>>> pistons are not interchangeable. >>>>> >>>>> If you need a new piston for a Yak 52 pop off valve, I believe Jill > >>>>> has them and so does Cliff Coy at Border Air. The spring for the >>>>> 52's pop off valve may be a little harder to find. But Jill or >>>>> Cliff can help with that. >>>>> >>>>> We have converted a few Yak 52's to the CJ6 pop off valve assembly >>>>> with the two Chinese check valves because the Chinese check valves >>>>> are significantly less expensive and Doug typically has them or >> overhaul >>>>> kits in stock. (Thank you Doug). The Russian check valves are >> VERY >>>>> expensive, IF you can find them. >>>>> >>>>> Dennis >>>>> >>>>> A. Dennis Savarese >>>>> 334-285-6263 >>>>> 334-546-8182 (mobile) >>>>> www.yak-52.com >>>>> Skype - Yakguy1 >>>>> >>>>> On 6/6/2013 11:34 AM, Bitterlich, Mark G CIV NAVAIR, WD wrote: >WD" >> >>>>>> >>>>>> >>>>>> Just FYI. >>>>>> >>>>>> The CJ6 valve ASSEMBLY that Doug has, is not always a direct >>>>>> replacement for every YAK pressure relief valve. Slightly >>>>>> different fittings in some cases. >>>>>> >>>>>> But the answer is obvious. If you take apart HIS valve and remove > >>>>>> the sealing piston, spring and screw on pressure adjusting top >>>>>> piece, and put them on yours, they fit perfectly and will work >> perfectly. >>>>>> >>>>>> You will then have to reset your maximum pressure. Be careful. >>>>>> >>>>>> Mark Bitterlich >>>>>> >>>>>> >>>>>> -----Original Message----- >>>>>> From: owner-yak-list-server@matronics.com >>>>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Cory >>>>>> Robin >>>>>> Sent: Thursday, June 06, 2013 1:00 >>>>>> To: yak-list@matronics.com >>>>>> Subject: Re: Yak-List: Air system 'stuff' >>>>>> >>>>>> Thank you all. I contacted Doug and have a valve on it's way. >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >> >> >> >> >> >> >> >> >> >> > > ________________________________ Message 11 ____________________________________ Time: 12:15:15 PM PST US Subject: RE: Yak-List: Air system 'stuff' From: "Bitterlich, Mark G CIV NAVAIR, WD" Thanks for the expert advice Doug. I had never even considered that. By the way, there is an air filter of sorts in the YAK-50. It is located on the "T" air divider area where all the check valves are located (four of them). It appears to be a circular device with fittings at both ends and is possibly filled with something like steel wool. In any case, whatever was in mine came all to pieces and junked up the check valves. Again: Good advice on a better filter. Hmmm. Mark -----Original Message----- From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of doug sapp Sent: Monday, June 10, 2013 14:44 Subject: Re: Yak-List: Air system 'stuff' Cory, Mark is correct in all he said, however the valve which you have selected would be somewhat prone to problems if your upstream air system is not 100% free of foreign material, such as old std steel rusted spring parts, dirt, grease, etc. These valves are intended for use in clean environments, not the somewhat dirtier systems of the CJ6. Placing the valve just after a high quality filter would both extend it's life and lower the probability of reoccurring maintenance issues I'm sure. Best, Doug On Mon, Jun 10, 2013 at 11:12 AM, Bitterlich, Mark G CIV NAVAIR, WD wrote: WD" Cory, Sorry to disagree, but just in the details. The valves that you referenced are indeed pop-off valves. They open to release or by-pass pressure to keep at a maintained value, exactly as does the pressure relief valve that is in there now. That said, they are of much better design and should work much better than the ones that are in there now, if you get one rated for the pressure and flow for our application. Taken from the company's web site: "Although this valve operates very similar to a relief valve which is usually designed to release pressure quickly as soon as the set pressure is exceeded , this valve is designed to relieve pressure more gradually with changes in flow resulting in fewer pressure spikes when the valve opens and closes. This is a direct-acting valve with an adjustable spring operating against a piston subjected to the inlet pressure of the valve. Increasing the spring compression will increase the system or line pressure to be maintained. Reducing the spring compression will reduce the system or line pressure to be maintained. " The summation: "An increase in system pressure beyond the set point will cause the main valve to open and relieve or bypass the excess pressure." This is EXACTLY how our present valves work, but these are easier to get and maintain. Mark p.s. Probably a darn good replacement. -----Original Message----- From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Cory Robin Sent: Sunday, June 09, 2013 10:09 To: yak-list@matronics.com Subject: Re: Yak-List: Air system 'stuff' I found a source of a back pressure relief valve. Rather than it popping off and reducing the pressure, it maintains the pressure at your pre-set value. I've ordered a couple to test them. https://straval.com/catlist-back-pressure-regulators/back-pressure-regul ator-piston-angle-valve-threaded-bps-05 ========== rget="_blank">http://www.matronics.com/Navigator?Yak-List ========== http://forums.matronics.com ========== le, List Admin. ="_blank">http://www.matronics.com/contribution ========== ________________________________ Message 12 ____________________________________ Time: 01:37:56 PM PST US Subject: Yak-List: Stall warning indicator switch. From: Bradly Banks SGVsbG8gYWdhaW4gYWxsLCBUb2RheSBJJ20gaG9waW5nIHRvIHRyYWNrIGRvd24gYSBzdXBwbGll ciBvZiBzdGFsbCB3YXJuaW5nIGluZGljYXRvciBzd2l0Y2hlcyBmb3IgYm90aCB0aGUgMTggdCBh bmQgdGhlIDUyLgpBbnkgaWRlYXMgb24gdGhlIHN1YmplY3QuwqAKVGhhbmtzCkJyYWQgQmFua3MK CgoKClNlbnQgZnJvbSBTYW1zdW5nIE1vYmlsZQ= ________________________________ Message 13 ____________________________________ Time: 02:15:32 PM PST US Subject: Re: Yak-List: Air system 'stuff' From: "Roger Kemp M.D." Mark, Since you have an 80, does Yours have the filter oriented in the vertical vs horizontal like mine in the pictures. If so you could put Doug's desiccant filter in line easily I would think. With mine I'm still searching for a point to mount it to that does not require 3 feet of aeroquip hoses each way. As for my aluminum hoses, they were once soft. They are annealed and brittle now. Had a hell of a time putting a new flair in one of the lines for the new air tank. Finally just replaced it! Should have done in every damned one of them when everything stripped out of the fuselage rebuilding all of the copper sleeved push pull cables to the throttle, louvers, and the prop governor. Fun times fabricating new threaded ends and swaging them on the cable. Do that one after you have threaded the new cable through the new copper tubing otherwise you are going to call you ancestry really ugly names! Doc Sent from my iPad On Jun 10, 2013, at 2:10 PM, "Bitterlich, Mark G CIV NAVAIR, WD" wrote: > > Thanks for the expert advice Doug. I had never even considered that. > > By the way, there is an air filter of sorts in the YAK-50. It is > located on the "T" air divider area where all the check valves are > located (four of them). It appears to be a circular device with > fittings at both ends and is possibly filled with something like steel > wool. In any case, whatever was in mine came all to pieces and junked > up the check valves. > > Again: Good advice on a better filter. Hmmm. > > Mark > > > -----Original Message----- > From: owner-yak-list-server@matronics.com > [mailto:owner-yak-list-server@matronics.com] On Behalf Of doug sapp > Sent: Monday, June 10, 2013 14:44 > To: yak-list@matronics.com > Subject: Re: Yak-List: Air system 'stuff' > > Cory, > Mark is correct in all he said, however the valve which you have > selected would be somewhat prone to problems if your upstream air system > is not 100% free of foreign material, such as old std steel rusted > spring parts, dirt, grease, etc. These valves are intended for use in > clean environments, not the somewhat dirtier systems of the CJ6. > Placing the valve just after a high quality filter would both extend > it's life and lower the probability of reoccurring maintenance issues > I'm sure. > > Best, > Doug > > > On Mon, Jun 10, 2013 at 11:12 AM, Bitterlich, Mark G CIV NAVAIR, WD > wrote: > > > WD" > > Cory, > > Sorry to disagree, but just in the details. The valves that > you referenced are indeed pop-off valves. They open to release or > by-pass pressure to keep at a maintained value, exactly as does the > pressure relief valve that is in there now. That said, they are of much > better design and should work much better than the ones that are in > there now, if you get one rated for the pressure and flow for our > application. > > Taken from the company's web site: > > "Although this valve operates very similar to a relief valve > which is usually designed to release pressure quickly as soon as the set > pressure is exceeded , this valve is designed to relieve pressure more > gradually with changes in flow resulting in fewer pressure spikes when > the valve opens and closes. This is a direct-acting valve with an > adjustable spring operating against a piston subjected to the inlet > pressure of the valve. Increasing the spring compression will increase > the system or line pressure to be maintained. Reducing the spring > compression will reduce the system or line pressure to be maintained. " > > The summation: > > "An increase in system pressure beyond the set point will cause > the main valve to open and relieve or bypass the excess pressure." > > This is EXACTLY how our present valves work, but these are > easier to get and maintain. > > Mark > > p.s. Probably a darn good replacement. > > > -----Original Message----- > From: owner-yak-list-server@matronics.com > [mailto:owner-yak-list-server@matronics.com] On Behalf Of Cory Robin > Sent: Sunday, June 09, 2013 10:09 > To: yak-list@matronics.com > Subject: Re: Yak-List: Air system 'stuff' > > I found a source of a back pressure relief valve. Rather than > it popping off and reducing the pressure, it maintains the pressure at > your pre-set value. > > I've ordered a couple to test them. > > > https://straval.com/catlist-back-pressure-regulators/back-pressure-regul > ator-piston-angle-valve-threaded-bps-05 > > > > > > > > ========== > rget="_blank">http://www.matronics.com/Navigator?Yak-List > ========== > http://forums.matronics.com > ========== > le, List Admin. > ="_blank">http://www.matronics.com/contribution > ========== > > > > > > > > > > > > > > > ________________________________ Message 14 ____________________________________ Time: 02:43:56 PM PST US Subject: Re: Yak-List: Air system 'stuff' From: doug sapp Mark, It has been my experience that 75% or more of the failures of QSF2A valves (3 port valves to you 52 types), and 12-5522-00 (5 port valve) are caused not by moisture/rust but by grit and or pieces of rusted springs. Years of rusty springs and poor maintenance has resulted in the majority of the air systems out there being contaminated to some degree. To combat the base problem we switched to all stainless steel springs in most all of our valves quite some time ago. The secondary problem of contaminated pneumatic problems is harder to solve as flushing the system out is very difficult. We are experimenting with the installation of a second stainless steel desiccant filter installed just prior to the rear gear valve, if successful this should vastly extend the life of these expensive valves. Best, Doug On Mon, Jun 10, 2013 at 12:10 PM, Bitterlich, Mark G CIV NAVAIR, WD < mark.bitterlich@navy.mil> wrote: > mark.bitterlich@navy.mil> > > Thanks for the expert advice Doug. I had never even considered that. > > By the way, there is an air filter of sorts in the YAK-50. It is > located on the "T" air divider area where all the check valves are > located (four of them). It appears to be a circular device with > fittings at both ends and is possibly filled with something like steel > wool. In any case, whatever was in mine came all to pieces and junked > up the check valves. > > Again: Good advice on a better filter. Hmmm. > > Mark > > > -----Original Message----- > From: owner-yak-list-server@matronics.com > [mailto:owner-yak-list-server@matronics.com] On Behalf Of doug sapp > Sent: Monday, June 10, 2013 14:44 > To: yak-list@matronics.com > Subject: Re: Yak-List: Air system 'stuff' > > Cory, > Mark is correct in all he said, however the valve which you have > selected would be somewhat prone to problems if your upstream air system > is not 100% free of foreign material, such as old std steel rusted > spring parts, dirt, grease, etc. These valves are intended for use in > clean environments, not the somewhat dirtier systems of the CJ6. > Placing the valve just after a high quality filter would both extend > it's life and lower the probability of reoccurring maintenance issues > I'm sure. > > Best, > Doug > > > On Mon, Jun 10, 2013 at 11:12 AM, Bitterlich, Mark G CIV NAVAIR, WD > wrote: > > > WD" > > Cory, > > Sorry to disagree, but just in the details. The valves that > you referenced are indeed pop-off valves. They open to release or > by-pass pressure to keep at a maintained value, exactly as does the > pressure relief valve that is in there now. That said, they are of much > better design and should work much better than the ones that are in > there now, if you get one rated for the pressure and flow for our > application. > > Taken from the company's web site: > > "Although this valve operates very similar to a relief valve > which is usually designed to release pressure quickly as soon as the set > pressure is exceeded , this valve is designed to relieve pressure more > gradually with changes in flow resulting in fewer pressure spikes when > the valve opens and closes. This is a direct-acting valve with an > adjustable spring operating against a piston subjected to the inlet > pressure of the valve. Increasing the spring compression will increase > the system or line pressure to be maintained. Reducing the spring > compression will reduce the system or line pressure to be maintained. " > > The summation: > > "An increase in system pressure beyond the set point will cause > the main valve to open and relieve or bypass the excess pressure." > > This is EXACTLY how our present valves work, but these are > easier to get and maintain. > > Mark > > p.s. Probably a darn good replacement. > > > -----Original Message----- > From: owner-yak-list-server@matronics.com > [mailto:owner-yak-list-server@matronics.com] On Behalf Of Cory Robin > Sent: Sunday, June 09, 2013 10:09 > To: yak-list@matronics.com > Subject: Re: Yak-List: Air system 'stuff' > > I found a source of a back pressure relief valve. Rather than > it popping off and reducing the pressure, it maintains the pressure at > your pre-set value. > > I've ordered a couple to test them. > > > https://straval.com/catlist-back-pressure-regulators/back-pressure-regul > ator-piston-angle-valve-threaded-bps-05 > > > ========== > rget="_blank">http://www.matronics.com/Navigator?Yak-List > ========== > http://forums.matronics.com > ========== > le, List Admin. > ="_blank">http://www.matronics.com/contribution > ========== > > ________________________________ Message 15 ____________________________________ Time: 04:06:23 PM PST US From: Robin Hou Subject: Re: Yak-List: Air system 'stuff' Doug, In Feb. this year, my CJ-6 had a failed check valve (right side firewall co nnected to emergency air tank). Pieces of this rusty spring went through th e entire system and caused havoc on other check valves, front landing gear valve, main air valve and QDF-1 air start solenoid valve. I overhauled and/ or replaced damaged valves except the QDF-1. I did not replace my QDF-1 because it had less than 25 hours on it at the t ime.-Reading yours and others' old posts on this list, I tried flushing t he QDF-1 with WD-40 and it worked. The initial WD-40 flush was dark brown i n color. After half dozen flushes, WD-40 came out clear, and QDF-1 would wo rk for a few starts before it gunked up and failed again. I would repeat th e WD-40 flush to keep QDF-1 going, and each time it kept going for a longer period than before. My last WD-40 flush was more than 2 months ago, and I had more than a dozen engine starts since then without issue. Based on this experience, do you think the QDF-1 air inlet would be a good location for an additional filter? Robin --- On Mon, 6/10/13, doug sapp wrote: From: doug sapp Subject: Re: Yak-List: Air system 'stuff' Mark,It has been my experience that 75% or more of the failures of QSF2A va lves (3 port valves to you 52 types), and 12-5522-00 (5 port valve) are cau sed not by moisture/rust but by grit and or pieces of rusted springs. -Ye ars of rusty springs and poor maintenance has resulted in the majority of t he air systems out there being-contaminated-to some degree. -To comba t the base problem we switched to all stainless steel springs in most all o f our valves quite some time ago. -The secondary problem of-contaminate d pneumatic problems is harder to solve as flushing the system out is very difficult. -We are-experimenting with the installation of a second stai nless steel desiccant filter installed just prior to the rear gear valve, i f-successful-this should vastly extend the life of these expensive valv es.=0A Best,Doug- On Mon, Jun 10, 2013 at 12:10 PM, Bitterlich, Mark G CIV NAVAIR, WD wrote: k.bitterlich@navy.mil> =0A=0A =0AThanks for the expert advice Doug. -I had never even considered that. =0A =0ABy the way, there is an air filter of sorts in the YAK-50. -It is =0Alocated on the "T" air divider area where all the check valves are =0Alocated (four of them). -It appears to be a circular device with =0Afittings at both ends and is possibly filled with something like steel =0Awool. -In any case, whatever was in mine came all to pieces and junked =0Aup the check valves. =0A =0AAgain: Good advice on a better filter. -Hmmm. =0A =0AMark =0A =0A =0A-----Original Message----- =0AFrom: owner-yak-list-server@matronics.com =0A[mailto:owner-yak-list-server@matronics.com] On Behalf Of doug sapp =0ASent: Monday, June 10, 2013 14:44 =0ATo: yak-list@matronics.com =0ASubject: Re: Yak-List: Air system 'stuff' =0A =0ACory, =0AMark is correct in all he said, however the valve which you have =0Aselected would be somewhat prone to problems if your upstream air system =0Ais not 100% free of foreign material, such as old std steel rusted =0Aspring parts, dirt, grease, etc. -These valves are intended for use in =0Aclean environments, not the somewhat dirtier systems of the CJ6. =0APlacing the valve just after a high quality filter would both extend =0Ait's life and lower the probability of reoccurring maintenance issues =0AI'm sure. =0A =0ABest, =0ADoug =0A =0A =0AOn Mon, Jun 10, 2013 at 11:12 AM, Bitterlich, Mark G CIV NAVAIR, WD =0A wrote: =0A =0A NAVAIR, =0AWD" =0A =0A- - - - Cory, =0A =0A- - - - Sorry to disagree, but just in the details. - The valv es that =0Ayou referenced are indeed pop-off valves. -They open to release or =0Aby-pass pressure to keep at a maintained value, exactly as does the =0Apressure relief valve that is in there now. -That said, they are of mu ch =0Abetter design and should work much better than the ones that are in =0Athere now, if you get one rated for the pressure and flow for our =0Aapplication. =0A =0A- - - - Taken from the company's web site: =0A =0A- - - - "Although this valve operates very similar to a relief v alve =0Awhich is usually designed to release pressure quickly as soon as the set =0Apressure is exceeded , this valve is designed to relieve pressure more =0Agradually with changes in flow resulting in fewer pressure spikes when =0Athe valve opens and closes. This is a direct-acting valve with an =0Aadjustable spring operating against a piston subjected to the inlet =0Apressure of the valve. Increasing the spring compression will increase =0Athe system or line pressure to be maintained. Reducing the spring =0Acompression will reduce the system or line pressure to be maintained. " =0A =0A- - - - The summation: =0A =0A- - - - "An increase in system pressure beyond the set point wil l cause =0Athe main valve to open and relieve or bypass the excess pressure." =0A =0A- - - - This is EXACTLY how our present valves work, but these a re =0Aeasier to get and maintain. =0A =0A- - - - Mark =0A =0A- - - - p.s. -Probably a darn good replacement. =0A =0A =0A- - - - -----Original Message----- =0A- - - - From: owner-yak-list-server@matronics.com =0A[mailto:owner-yak-list-server@matronics.com] On Behalf Of Cory Robin =0A- - - - Sent: Sunday, June 09, 2013 10:09 =0A- - - - To: yak-list@matronics.com =0A- - - - Subject: Re: Yak-List: Air system 'stuff' =0A =0A- - - - I found a source of a back pressure relief valve. - Ra ther than =0Ait popping off and reducing the pressure, it maintains the pressure at =0Ayour pre-set value. =0A =0A- - - - I've ordered a couple to test them. =0A =0A =0Ahttps://straval.com/catlist-back-pressure-regulators/back-pressure-regul =0Aator-piston-angle-valve-threaded-bps-05 =0A =0A =0A =0A =0A =0A =0A =0A- - - - ========== =0A- - - - rget="_blank">http://www.matronics.com/Navigator?Yak-L ist =0A- - - - ========== =0A- - - - http://forums.matronics.com =0A- - - - ========== =0A- - - - le, List Admin. =0A- - - - ="_blank">http://www.matronics.com/contribution =0A- - - - ========== =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A========== =0Arget="_blank">http://www.matronics.com/Navigator?Yak-List =0A========== =0Ahttp://forums.matronics.com =0A========== =0Ale, List Admin. =0A="_blank">http://www.matronics.com/contribution =0A========== =0A =0A =0A =0A ==================0A=0A ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message yak-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Yak-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/yak-list Browse Digests http://www.matronics.com/digest/yak-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.