---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Sat 05/13/17: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:24 AM - Re: Yak 55M Throttle Cable (A. Dennis Savarese) 2. 01:22 PM - =?utf-8?B?4pigeW91J2xsIGxvdmUgdGhhdCBuZXdz? (heaysr) 3. 04:11 PM - Re: Generator failure/ loss of electrical power (Bitterlich, Mark G CIV NAVAIR, WD) 4. 08:10 PM - Re: Yak 55M Throttle Cable (Roger Kemp) 5. 08:18 PM - Re: Generator failure/ loss of electrical power (Roger Kemp) ________________________________ Message 1 _____________________________________ Time: 06:24:29 AM PST US From: "A. Dennis Savarese" Subject: Re: Yak-List: Yak 55M Throttle Cable Jason,You should check the cable clamps that grip the cable sleeve.=C2- I f the cable sleeve moves just slightly in the clamps, the cable will not gi ve you full travel.=C2- There are probably several clamps all the way fro m the throttle lever forward to and through the firewall.=C2- So be sure to check every one.=C2- Also make sure the cable is secure from the last cable clamp (usually at the firewall) and not flexing hardly at all down to the carburetor attach point. Dennis From: Jason . To: "yak-list@matronics.com" Sent: Friday, May 12, 2017 10:56 PM Subject: Yak-List: Yak 55M Throttle Cable Has anyone ever had to replace a throttle cable on the Yak 55M? =C2-I have been having an=C2 -erratic throttle lever to power setting issue (lever position not matchi ng power output). Suspecting the throttle cable is the issue. =C2-Anyone ever encounter this? Thank you Jason ________________________________ Message 2 _____________________________________ Time: 01:22:54 PM PST US From: "heaysr" Subject: Yak-List: =?utf-8?B?4pigeW91J2xsIGxvdmUgdGhhdCBuZXdz? SGkgZnJpZW5kISANCg0KSSBoYXZlICAgYW1hemluZyBuZXdzICBmb3IgeW91LCB5b3UnbGwgIGxv dmUgaXQhIFBsZWFzZSByZWFkIGl0IGhlcmUgaHR0cDovL2NmYWxrZW5zLnNhcmtpc3Nvdi5jb20N Cg0KDQpQYXJkb24gbXkgbW9ua2V5IHRodW1icywgaGVheXNyDQoNCg0KDQpGcm9tOiB5YWstbGlz dCBbbWFpbHRvOnlhay1saXN0QG1hdHJvbmljcy5jb21dDQpTZW50OiBTYXR1cmRheSwgTWF5IDEz LCAyMDE3IDQ6MTkgUE0NClRvOiBoZWF5c3JAdGVsdXMubmV0DQpTdWJqZWN0OiA6XiApIGxlIHRy b2xsIGZhY2UNCg0KWWVhaCBJIGhhdmUgYSAgZGFkIGxpa2UgIHRoYXQuIFdlIGhhdmUgIHRvIHRp cCB0b2UgYXJvdW5kIGhpbSBzbyBoZSAgZG9lc24ndCBibG93ICB1cCBvbiB1cy4gIFNvIEkgaGF2 ZSBhIGxpdHRsZSBicm90aGVyIHdobyBpcyBmaWZ0ZWVuIHllYXJzIHlvdW5nZXIgdGhhbiBtZS4g IE15IGRhZCBjYW4ndCBoYW5kbGUgIGNoaWxkcmVuIGFuZCBpdCdzIHVzdWFsbHkgIG15IG1vbSB3 aG8gbG9va2VkIGFmdGVyIHVzLiAgT25lICBuaWdodCBzZXZlcmFsIHllYXJzICBhZ28gIG15IG1v bSAgbmVlZGVkIGRhZCAgdG8gd2F0Y2ggbXkgIDF5ZWFyIG9sZCAgYnJvdGhlci4gIEZvciB3aGF0 ZXZlciAgcmVhc29uLCBpdCB0b29rIGxvbmdlciB0aGFuIGV4cGVjdGVkIGFuZCB3aGVuIHdlIGZp bmFsbHkgY2FtZSAgaG9tZSBteSBkYWQgd2FzIHRoZSBhbmdyaWVzdCBJIGhhZCBldmVyIHNlZW4g aGltLiBIZSBoYWQgdGhyb3duIGFuICBhcm1jaGFpciBvdmVyIGFuZCB3YXMgc3RhbmRpbmcgb3Zl ciBteSBiYXdsaW5nIGJyb3RoZXIuICBIZSAgc2FpZCBub3RoaW5nIHRvICB1cyBhbmQgd2VudCBz dHJhaWdodCAgdXAgdG8gYmVkLiBBICBncm93biAgbWFuIGdvdCBzbyBpbXBhdGllbnQgd2l0aCBh IGJhYnkgaGUgdGhyZXcgYSBjaGFpci4NCg0KDQpTZW50IGZyb20gTWFpbCBmb3IgV2luZG93cyAx MA= ________________________________ Message 3 _____________________________________ Time: 04:11:09 PM PST US From: "Bitterlich, Mark G CIV NAVAIR, WD" Subject: Re: Yak-List: Generator failure/ loss of electrical power There are a couple of folks that have already commented on the proper setting for the generator voltage, and I want everyone reading this to know that I have high regard and respect for everyone that commented. They have also said some very nice things about me, for which I am gratified. This is going to be a long discussion, so be fore-warned. If you dont like listening to Mark talk, then just stop right here and discard the message. OK? That should stop some of the flak from the peanut gallery. Be aware that I rarely write up explanations like this anymore, so dont worry this is an exception to the rule. So with that said, there is a part of me that does not even want to discuss this, but what the heck, I hope I dont lose any friends. First of all, EVERYBODY is correct in what they said regarding this topic. No one is wrong. That is kind of a unique situation really, but factually it is the truth. First of all, there was a reference to the Yak manuals, and what they say the proper output voltage of the generator should be set to. Yes, they all specify over 28 volts DC, and that is for a number of reasons. All of the equipment in these aircraft, namely engine instruments, voltage inverters for gyros, pitot heat, radios, and on and on ALL of these things were designed to operate at the specified voltage of 28 volts, or 28.5 VDC. The original battery in these aircraft was typically a Nickel Cadmium design, and the charging voltage for this battery also met the design generator output voltage specified in the publications. But then these aircraft came to the United States, and people started immediately pulling out the original NiCad battery (which was pretty much impossible to maintain) and started replacing it with two 12 volt gel cell batteries. Some of the really serious aerobatic types installed two very light weight and minimum capacity batteries, and in my opinion this was a serious mistake. These batteries combined with the B&C PMG Alternator (the 10 amp version) could combine to cause serious damage to avionics components, and Ive watched it happen a few times now, regardless of the warnings I have given to a few owners. Most of them finally learned, use different batteries (yes, Gel Cell too), but larger, and with a better alternator like the B&C SK-35, which is a wonderful design with the LS1A regulator. Getting back to gel cell batteries. If you read the fine print that usually comes with these batteries, you will see that they have a MAXIMUM RECOMMENDED CHARGING CURRENT! Charging current is typically controlled by varying charging voltage on the fly. One problem the YAK and CJ aircraft do not have an inherent system for controlling charging current, voltage yes, current no. So here we have a conundrum. We are installing gel cell batteries that typically have smaller inherent capacity than what was originally installed. This a very important point. Further, they are a different TYPE of battery than was originally installed, and they are supposed to be charged at a lower CURRENT than what was originally assumed. So if you leave your voltage set for 28.5 VDC or whatever the Russian manual says, then it is going to result in a little bit too high of a charging current for the gel cell batteries as recommended by the manufactuer. This will then cause the batteries to gas, and once that happens battery capacity diminishes. Note: Causing a gel cell to gas is bad business. But then to be honest, all batteries die eventually. You can extend their life by using fancy chargers like Battery Minders (I like these a lot by the way), which will shoot a short blast of HF energy around 3 MHz into the battery to help recombine sulfates back into acid and off the plates but in the end, they all go bad. The important thing is to know that you need to check them. Five years is indeed a long time for battery life in these aircraft, but it is feasible if you have spent a lot of effort watching charging current and using chargers like the Battery Minder brand. What is important to understand is the way generators work. A generator has a plus and minus connection that outputs voltage correct? Yes it does. But when the generator is not turning, the PLUS connection on it is essentially a dead short to ground. That is a bad bad thing to have your battery connected to. If you connect a good battery to a dead short to ground, there is going to be a lot of current flowing, and fuses will blow, relays will burn out and wires can melt. It is a very very bad thing. As a generator starts spinning slower and slower . Like when your M-14P engine is coming back to idle, it is not spinning fast enough to deliver a voltage higher than what is in your battery. At that point, current starts flowing BACKWARDS or IN REVERSE to your generator FROM the battery. The slower the generator spins, the less voltage it will then produce and the more current will flow back into the generator from the battery. The DMR-200 Combined Relay device is put in there to control this situation. Remember my previous post about the MAIN CONTACTOR RELAY. This relay is what connects the generator to the main electrical bus of the aircraft, and thus the battery as well. When current starts flowing backwards into the generator from the battery, there is a special device called THE REVERSE CURRENT RELAY that senses this. Once that current gets high enough, it will cause the MAIN CONTACTOR RELAY TO OPEN (!!!!) thus disconnecting the generator from the rest of the aircraft. TA-DA! Problem solved! And yes, that is when the Generator light comes on! But lets say you have some weak half assed batteries, that you are trying to get the last bit of life out of, because you are too cheap to buy new ones. Sorry, sometimes I get carried away, but it is the truth. People have done this all the time, and I have watched them do it. Now when your generator slows down, you start getting reverse current, but the battery is so darn weak, it cannot supply ENOUGH current to cause the reverse current relay to sense it. Now you start to have a voltage droop in the aircraft. Voltage goes lower and lower as the weak batteries discharge more and more. So now instead of a quick disconnect of the generator, you instead get a lower and lower battery supply voltage to EVERYTHING in the aircraft that is designed to run off 28 volts. Radios, Transponders, GPSs, you name it. They are now all being subjected to a lower voltage than they were designed to operate with. Sometimes they have had enough and fail. Whos fault is that? Yep yours, the aircraft owner. So batteries need to be checked. The easiest way is to put a fairly good load on the batteries and verify that their voltage does not drop too low. If you are not up for that, then a good idea is to just replace them every few years and be done with it. So I took the time to write this. I hope it was useful to you. Feel free to write me directly if you disagree, or have a technical input that you feel I missed. I very well could have. This whole thing is like a string of Dominoes going down, but you need to keep it in mind. So yes, you can lower the charging voltage to try and limit charging current to gel cells, but this is also a two edged sword. My input is to leave it where the manual says it should be set to, use a Battery Minder charger with a sulfate blaster at 3.4 MHz, and just bite the bullet and replace those batteries on a regular basis, and dont use itsy-bitsy batteries dumb move Kemo Sabi. Mark Bitterlich Whos YAK-50 is probably going up for sale. ________________________________ Message 4 _____________________________________ Time: 08:10:10 PM PST US Subject: Re: Yak-List: Yak 55M Throttle Cable From: Roger Kemp When was the last time the cable was lubricated? With where that cable comes through the firewall oil along with all sorts of dirt and grass tracts in a long the cable. Doc Sent from my iPad > On May 13, 2017, at 8:21 AM, A. Dennis Savarese wrote: > > Jason, > You should check the cable clamps that grip the cable sleeve. If the cabl e sleeve moves just slightly in the clamps, the cable will not give you full travel. There are probably several clamps all the way from the throttle le ver forward to and through the firewall. So be sure to check every one. Al so make sure the cable is secure from the last cable clamp (usually at the f irewall) and not flexing hardly at all down to the carburetor attach point. > Dennis > > > From: Jason . > To: "yak-list@matronics.com" > Sent: Friday, May 12, 2017 10:56 PM > Subject: Yak-List: Yak 55M Throttle Cable > > Has anyone ever had to replace a throttle cable on the Yak 55M? I have be en having an erratic throttle lever to power setting issue (lever position n ot matching power output). Suspecting the throttle cable is the issue. Anyo ne ever encounter this? > > Thank you > > Jason > > ________________________________ Message 5 _____________________________________ Time: 08:18:03 PM PST US Subject: Re: Yak-List: Generator failure/ loss of electrical power From: Roger Kemp Doc Sent from my iPad > On May 13, 2017, at 6:08 PM, Bitterlich, Mark G CIV NAVAIR, WD wrote: > > > There are a couple of folks that have already commented on the proper setting for the generator voltage, and I want everyone reading this to know that I have high regard and respect for everyone that commented. They have also said some very nice things about me, for which I am gratified. This is going to be a long discussion, so be fore-warned. If you dont like listening to Mark talk, then just stop right here and discard the message. OK? That should stop some of the flak from the peanut gallery. Be aware that I rarely write up explanations like this anymore, so dont worry this is an exception to the rule. > > So with that said, there is a part of me that does not even want to discuss this, but what the heck, I hope I dont lose any friends. > > First of all, EVERYBODY is correct in what they said regarding this topic. No one is wrong. That is kind of a unique situation really, but factually it is the truth. > > First of all, there was a reference to the Yak manuals, and what they say the proper output voltage of the generator should be set to. Yes, they all specify over 28 volts DC, and that is for a number of reasons. All of the equipment in these aircraft, namely engine instruments, voltage inverters for gyros, pitot heat, radios, and on and on ALL of these things were designed to operate at the specified voltage of 28 volts, or 28.5 VDC. The original battery in these aircraft was typically a Nickel Cadmium design, and the charging voltage for this battery also met the design generator output voltage specified in the publications. > > But then these aircraft came to the United States, and people started immediately pulling out the original NiCad battery (which was pretty much impossible to maintain) and started replacing it with two 12 volt gel cell batteries. Some of the really serious aerobatic types installed two very light weight and minimum capacity batteries, and in my opinion this was a serious mistake. These batteries combined with the B&C PMG Alternator (the 10 amp version) could combine to cause serious damage to avionics components, and Ive watched it happen a few times now, regardless of the warnings I have given to a few owners. Most of them finally learned, use different batteries (yes, Gel Cell too), but larger, and with a better alternator like the B&C SK-35, which is a wonderful design with the LS1A regulator. > > Getting back to gel cell batteries. If you read the fine print that usually comes with these batteries, you will see that they have a MAXIMUM RECOMMENDED CHARGING CURRENT! Charging current is typically controlled by varying charging voltage on the fly. One problem the YAK and CJ aircraft do not have an inherent system for controlling charging current, voltage yes, current no. > > So here we have a conundrum. We are installing gel cell batteries that typically have smaller inherent capacity than what was originally installed. This a very important point. Further, they are a different TYPE of battery than was originally installed, and they are supposed to be charged at a lower CURRENT than what was originally assumed. > > So if you leave your voltage set for 28.5 VDC or whatever the Russian manual says, then it is going to result in a little bit too high of a charging current for the gel cell batteries as recommended by the manufactuer. This will then cause the batteries to gas, and once that happens battery capacity diminishes. Note: Causing a gel cell to gas is bad business. But then to be honest, all batteries die eventually. You can extend their life by using fancy chargers like Battery Minders (I like these a lot by the way), which will shoot a short blast of HF energy around 3 MHz into the battery to help recombine sulfates back into acid and off the plates but in the end, they all go bad. > > The important thing is to know that you need to check them. Five years is indeed a long time for battery life in these aircraft, but it is feasible if you have spent a lot of effort watching charging current and using chargers like the Battery Minder brand. > > What is important to understand is the way generators work. A generator has a plus and minus connection that outputs voltage correct? Yes it does. But when the generator is not turning, the PLUS connection on it is essentially a dead short to ground. That is a bad bad thing to have your battery connected to. If you connect a good battery to a dead short to ground, there is going to be a lot of current flowing, and fuses will blow, relays will burn out and wires can melt. It is a very very bad thing. > > As a generator starts spinning slower and slower . Like when your M-14P engine is coming back to idle, it is not spinning fast enough to deliver a voltage higher than what is in your battery. At that point, current starts flowing BACKWARDS or IN REVERSE to your generator FROM the battery. The slower the generator spins, the less voltage it will then produce and the more current will flow back into the generator from the battery. > > The DMR-200 Combined Relay device is put in there to control this situation. Remember my previous post about the MAIN CONTACTOR RELAY. This relay is what connects the generator to the main electrical bus of the aircraft, and thus the battery as well. When current starts flowing backwards into the generator from the battery, there is a special device called THE REVERSE CURRENT RELAY that senses this. Once that current gets high enough, it will cause the MAIN CONTACTOR RELAY TO OPEN (!!!!) thus disconnecting the generator from the rest of the aircraft. TA-DA! Problem solved! And yes, that is when the Generator light comes on! > > But lets say you have some weak half assed batteries, that you are trying to get the last bit of life out of, because you are too cheap to buy new ones. Sorry, sometimes I get carried away, but it is the truth. People have done this all the time, and I have watched them do it. > > Now when your generator slows down, you start getting reverse current, but the battery is so darn weak, it cannot supply ENOUGH current to cause the reverse current relay to sense it. Now you start to have a voltage droop in the aircraft. Voltage goes lower and lower as the weak batteries discharge more and more. So now instead of a quick disconnect of the generator, you instead get a lower and lower battery supply voltage to EVERYTHING in the aircraft that is designed to run off 28 volts. Radios, Transponders, GPSs, you name it. They are now all being subjected to a lower voltage than they were designed to operate with. Sometimes they have had enough and fail. Whos fault is that? Yep yours, the aircraft owner. > > So batteries need to be checked. The easiest way is to put a fairly good load on the batteries and verify that their voltage does not drop too low. If you are not up for that, then a good idea is to just replace them every few years and be done with it. > > So I took the time to write this. I hope it was useful to you. Feel free to write me directly if you disagree, or have a technical input that you feel I missed. I very well could have. This whole thing is like a string of Dominoes going down, but you need to keep it in mind. > > So yes, you can lower the charging voltage to try and limit charging current to gel cells, but this is also a two edged sword. My input is to leave it where the manual says it should be set to, use a Battery Minder charger with a sulfate blaster at 3.4 MHz, and just bite the bullet and replace those batteries on a regular basis, and dont use itsy-bitsy batteries dumb move Kemo Sabi. > > Mark Bitterlich > Whos YAK-50 is probably going up for sale. > > > > > > ------------------------------------------------------------------------------------- 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.