---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Tue 02/14/17: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:18 AM - Re: M-14P TBO (Richard Goode) 2. 12:23 AM - YAK55m wing bolt replacement (Steve Geard) 3. 12:25 AM - Re: M14P questions. (Richard Goode) 4. 12:49 AM - Re: M-14P TBO (Looigi) 5. 05:21 AM - Re: one way air valves (emergency system) (Greg Wrobel) 6. 08:46 AM - Re: M14P questions. (HawkerPilot2015) 7. 05:20 PM - Re: M14P questions. (Roger Kemp) 8. 08:10 PM - Re: YAK55m wing bolt replacement (Walter Lannon) 9. 10:15 PM - Re: YAK55m wing bolt replacement (Royden Heays) 10. 11:04 PM - Re: YAK55m wing bolt replacement (Jason Bialek) ________________________________ Message 1 _____________________________________ Time: 12:18:08 AM PST US From: "Richard Goode" Subject: RE: Yak-List: M-14P TBO The essential problem is that the Russians were extremely conservative; working in a "military" environment and trying to employ 300 million people - hence the very low TBO of these engines. But, those are the official figures from the manufacturer. We know from experience that if operated sensibly the engines are good for much longer TBOs. On the other hand, if an engine is in a Sukhoi in airshow work; operating at 103%; rapid changes of power settings, then you would be lucky to get more than 500 hours. But the fundamental international practice is that the original manufacturer dictates the TBO, and it is extremely rare that another body would give a conflicting figure. This is particularly true in the USA where the engine is not certified and is operated "experimentally" and therefore has no formal TBO figure. So, I would be very surprised if the FAA, or indeed any other aviation authority, had issued more generous figures for these engines. Unfortunately, in Europe, we have to obey the original manufacturer's figures. However, we no longer scrap an engine at 2250 hours but continue to use them, as long as each component is completely tested and is the equivalent of a new one. Richard Goode Aerobatics Rhodds Farm Lyonshall Hereford HR5 3LW Tel: +44 (0) 1544 340120 Fax: +44 (0) 1544 340129 www.russianaeros.com -----Original Message----- From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Looigi Sent: 14 February 2017 03:01 Subject: Yak-List: M-14P TBO Hi All, I am starting a new thread because I don't want to hijack any of the others here. I know I am opening an old debate and I have also searched old posts but I have not found what I am looking for. I am trying to find some documentation on the M-14P overhaul periods on a Yak-52 to satisfy our New Zealand CAA. I have been told that paper work exists to backup TBO's other than the 750 + 500 + 500 + 500, scrap at 2250 hours that is 'popular' here. Other guys here have managed to get TBO's past them with 2250 hours between overhauls! In the absence of manufacturers data the CAA seem to believe Wikipedia, not that they can show me any manufacturers data to back that up either!! They have said that if I can get a copy of an FAA approved Maintenance Program with longer TBO's they would accept that. Does anyone have a copy of such an FAA approved program that they would be willing to share please? Is there any other information available that looks credible with longer TBO's? Many thanks in advance Chris Read this topic online here: http://forums.matronics.com/viewtopic.php?p=466156#466156 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ________________________________ Message 2 _____________________________________ Time: 12:23:00 AM PST US Subject: Yak-List: YAK55m wing bolt replacement From: "Steve Geard" Hello all my 1992 YAK55m has 440 hours on it and is showing signs of play in both the front and rear wing attachments. Has anyone done a replacement of wing bolts? We're thinking if we reamed the holes oversize and bush them back to standard size all we need to do is refit original type bolts, also any future repair means replacing bush only. Also does anyone know what the attachments castings are made from :-) And whats the maximum oversize we can bore out to? Cheers Steve. Life's short fly aerobatics. -------- SteveO Read this topic online here: http://forums.matronics.com/viewtopic.php?p=466164#466164 ________________________________ Message 3 _____________________________________ Time: 12:25:39 AM PST US From: "Richard Goode" Subject: RE: Yak-List: M14P questions. Not true! As I wrote before, the port is for an intended modification for a centrifugal oil filter. But the more recent electric start conversion uses the mountings for the port, simply because they are convenient and in the right place. Richard Goode Aerobatics Rhodds Farm Lyonshall Hereford HR5 3LW Tel: +44 (0) 1544 340120 Fax: +44 (0) 1544 340129 www.russianaeros.com From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp Sent: 14 February 2017 01:52 Subject: Re: Yak-List: M14P questions. The large port on the nose case was for an electric starter. Series two cylinders have varying length fins for better cooling as I understand. They are apparently interchangeable since I have seen engines with a mix. Well maybe the assembler in St. Elsewhere was cheap and lazy. Doc Sent from my iPad On Feb 12, 2017, at 10:45 PM, Walter Lannon wrote: A couple of questions for the M14P experts on the list. Doing some work on a Series 2 engine and mystified by a couple of changes from the earlier model. Can anyone enlighten me? 1. What is the purpose of the large access port in the LH side of the nose case. 2. Significant changes to cylinder fin design. Presumably to improve cooling efficiency yet appears to reduce rather than increase cooling area. Many thanks; Walt _____ Avast logo This email has been checked for viruses by Avast antivirus software. www.avast.com -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ________________________________ Message 4 _____________________________________ Time: 12:49:37 AM PST US Subject: Yak-List: Re: M-14P TBO From: "Looigi" Thanks for that Richard. Can you point me at some data on using the engine beyond the 2250 hours I can beat our CAA about the head with please? Cheers Chris Read this topic online here: http://forums.matronics.com/viewtopic.php?p=466166#466166 ________________________________ Message 5 _____________________________________ Time: 05:21:50 AM PST US From: Greg Wrobel Subject: Re: Yak-List: one way air valves (emergency system) Morning Jon. Don't feel bad I am having same issue. One other time, I had this happen it WAS the emergency check valve as Ernie describes on the starboard firewall. My emmergency air would then hold forever and then for no apparent reason it would bleed to 30 atms in the first 24 hours and 24 hours later be at 0. I rebuilt the emmergency valve again but no change. I was told the other day to also check my gages so today I'm pulling the right panels and putting the leak check at the gages. I'll let you know if I find anything. Last week I rebuilt and/or replaced all 6 check valves on the firewall, all gear locks, 8 diverted valves, compressor banjo fitting, air drier and over pressure regulator. What an eye opener! On Feb 13, 2017 14:18, "Jon Boede" wrote: > My emergency air system on a stock CJ goes up *and down* with the main > air pressure. > > > This is a recent development. So I changed out all the one-way air valves > on the firewall and that didn't stop it. > > > Is there a one-way valve for the emergency air system, not forward on the > firewall, that I missed? > > > Or is there another reason the emergency air system would bleed down? The > emergency air valve hadn't been touched at any time around when this > started happening. > > > Jon > ________________________________ Message 6 _____________________________________ Time: 08:46:08 AM PST US Subject: Yak-List: Re: M14P questions. From: "HawkerPilot2015" I like the gun story...so I am going with that. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=466175#466175 ________________________________ Message 7 _____________________________________ Time: 05:20:41 PM PST US Subject: Re: Yak-List: M14P questions. From: Roger Kemp Copy Richard. The engines I have seen came with TWs and the Americanized 52 W. Was not intending to cast doubt. Doc Sent from my iPad > On Feb 14, 2017, at 2:25 AM, Richard Goode wrote: > > Not true! As I wrote before, the port is for an intended modification for a centrifugal oil filter. But the more recent electric start conversion uses t he mountings for the port, simply because they are convenient and in the rig ht place. > > Richard Goode Aerobatics > Rhodds Farm > Lyonshall > Hereford > HR5 3LW > > Tel: +44 (0) 1544 340120 > Fax: +44 (0) 1544 340129 > www.russianaeros.com > > From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@ma tronics.com] On Behalf Of Roger Kemp > Sent: 14 February 2017 01:52 > To: yak-list@matronics.com > Subject: Re: Yak-List: M14P questions. > > The large port on the nose case was for an electric starter. > Series two cylinders have varying length fins for better cooling as I unde rstand. They are apparently interchangeable since I have seen engines with a mix. Well maybe the assembler in St. Elsewhere was cheap and lazy. > Doc > > Sent from my iPad > > On Feb 12, 2017, at 10:45 PM, Walter Lannon wrote: > > A couple of questions for the M14P experts on the list. Doing some work o n a Series 2 engine and mystified by a couple of changes > from the earlier model. Can anyone enlighten me? > > 1. What is the purpose of the large access port in the LH side of the no se case. > > 2. Significant changes to cylinder fin design. Presumably to improve c ooling efficiency yet appears to reduce rather than increase cooling area. > > Many thanks; > Walt > > > > This email has been checked for viruses by Avast antivirus software. > www.avast.com > > > > -- > This message has been scanned for viruses and > dangerous content by MailScanner, and is > believed to be clean. ________________________________ Message 8 _____________________________________ Time: 08:10:43 PM PST US From: "Walter Lannon" Subject: Re: Yak-List: YAK55m wing bolt replacement Hi Steve; I have no specific information to offer you on the Yak 55 wing attachment, only a few general observations: The wing attach straps are not castings. These are high strength steel forgings, probably a Russian equivalent of AMS 4340 (or similar) and heat treated to a minimum UTS (ultimate tensile strength) of not less than 170,000 psi. The factory manual may allow the use of an oversize bolt (factory supplied) with rework of the fittings possibly by precision grinding rather than reaming. The maximum increase in hole dia. will likely be in the order of 0.25 - 0.5 mm (0.010 - 0.020 in.) A typical maximum clearance between the bolt and wing fitting would be in the order of 0.05 mm (0.002 in). If you know a good professional engineer have him do some measurements and calculate the lower attachment load at your normal (positive) max. "G" load. He will probably give you a number around 30 ton. Fly safe; Walt -----Original Message----- From: Steve Geard Sent: Tuesday, February 14, 2017 12:22 AM Subject: Yak-List: YAK55m wing bolt replacement Hello all my 1992 YAK55m has 440 hours on it and is showing signs of play in both the front and rear wing attachments. Has anyone done a replacement of wing bolts? We're thinking if we reamed the holes oversize and bush them back to standard size all we need to do is refit original type bolts, also any future repair means replacing bush only. Also does anyone know what the attachments castings are made from :-) And whats the maximum oversize we can bore out to? Cheers Steve. Life's short fly aerobatics. -------- SteveO Read this topic online here: http://forums.matronics.com/viewtopic.php?p=466164#466164 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 9 _____________________________________ Time: 10:15:08 PM PST US From: "Royden Heays" Subject: RE: Yak-List: YAK55m wing bolt replacement Hi Steve, I'm told that the main spar wing and fuselage fittings are titanium. Those fittings take on an oval shape with long term aerobatic loadings while the bolt remains perfectly circular at its original diameter. The fix is to ream the fittings and install over- sized bolts to match. Reaming titanium is not an easy matter and doing it while keeping the holes aligned so as not to change the rig is an added challenge. I was told you need a 17 flute reamer. There are two ways of getting oversized bolts. One is to build up the existing bolts and grind them back to the oversize diameter needed. The other is to order oversized bolts from the Yak 55 factory in Eastern Russia. As of two years ago Vladimir Yestremi had the equipment and contacts to do the whole job. I'm not sure if Vladimir is still in that business. Jill and Carl at M14P also have knowledge of the process. Jill - are you there - can you please comment? I did some calcs a couple of years ago as attached. Walt's 30 tons (imperial tons?) is pretty close to the 28 T (metric tons) I calculated. I'm not an aircraft engineer and don't stand behind the calcs. But they certainly convinced me to be very wary of having the right bolt strength. They are high end bolts that are required. Hopefully Vladimir reads this and can correct me if needed. Regards Royden -----Original Message----- From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon Sent: Tuesday, February 14, 2017 8:10 PM Subject: Re: Yak-List: YAK55m wing bolt replacement Hi Steve; I have no specific information to offer you on the Yak 55 wing attachment, only a few general observations: The wing attach straps are not castings. These are high strength steel forgings, probably a Russian equivalent of AMS 4340 (or similar) and heat treated to a minimum UTS (ultimate tensile strength) of not less than 170,000 psi. The factory manual may allow the use of an oversize bolt (factory supplied) with rework of the fittings possibly by precision grinding rather than reaming. The maximum increase in hole dia. will likely be in the order of 0.25 - 0.5 mm (0.010 - 0.020 in.) A typical maximum clearance between the bolt and wing fitting would be in the order of 0.05 mm (0.002 in). If you know a good professional engineer have him do some measurements and calculate the lower attachment load at your normal (positive) max. "G" load. He will probably give you a number around 30 ton. Fly safe; Walt -----Original Message----- From: Steve Geard Sent: Tuesday, February 14, 2017 12:22 AM Subject: Yak-List: YAK55m wing bolt replacement Hello all my 1992 YAK55m has 440 hours on it and is showing signs of play in both the front and rear wing attachments. Has anyone done a replacement of wing bolts? We're thinking if we reamed the holes oversize and bush them back to standard size all we need to do is refit original type bolts, also any future repair means replacing bush only. Also does anyone know what the attachments castings are made from :-) And whats the maximum oversize we can bore out to? Cheers Steve. Life's short fly aerobatics. -------- SteveO Read this topic online here: http://forums.matronics.com/viewtopic.php?p=466164#466164 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 10 ____________________________________ Time: 11:04:26 PM PST US From: Jason Bialek Subject: Re: Yak-List: YAK55m wing bolt replacement Usually forward spar is 80 percent and rear spar is 20 percent. There are load cases where one wing takes more load than the other when combining rolling loads with "under G" pitch rate loads. Regardless, important to know what the max gross we're trying to figure this out for. based on max gross and worst case maneuvering load we can begin to sneak up on the number the bolt should be good for. Jason Bialek yak55m KAWO > On Feb 14, 2017, at 9:15 PM, "Walter Lannon" wrote: > > > Hi Steve; > > I have no specific information to offer you on the Yak 55 wing attachment, only a few general observations: > > The wing attach straps are not castings. These are high strength steel forgings, probably a Russian equivalent of AMS 4340 (or similar) and heat treated to a minimum UTS (ultimate tensile strength) of not less than 170,000 psi. > > The factory manual may allow the use of an oversize bolt (factory supplied) with rework of the fittings possibly by precision grinding rather than reaming. > > The maximum increase in hole dia. will likely be in the order of 0.25 - 0.5 mm (0.010 - 0.020 in.) A typical maximum clearance between the bolt and wing fitting would be in the order of 0.05 mm (0.002 in). > > If you know a good professional engineer have him do some measurements and calculate the lower attachment load at your normal (positive) max. "G" load. > He will probably give you a number around 30 ton. > > Fly safe; > Walt > > -----Original Message----- From: Steve Geard > Sent: Tuesday, February 14, 2017 12:22 AM > To: yak-list@matronics.com > Subject: Yak-List: YAK55m wing bolt replacement > > > Hello all my 1992 YAK55m has 440 hours on it and is showing signs of play in both the front and rear wing attachments. > Has anyone done a replacement of wing bolts? > We're thinking if we reamed the holes oversize and bush them back to standard size all we need to do is refit original type bolts, also any future repair means replacing bush only. > Also does anyone know what the attachments castings are made from :-) > And whats the maximum oversize we can bore out to? > Cheers Steve. > Life's short fly aerobatics. > > -------- > SteveO > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=466164#466164 > > > > > > > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > > > ------------------------------------------------------------------------------------- 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.