---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Wed 02/05/14: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:23 AM - Worldwide YAK 50 survey (aerostar6) 2. 03:45 AM - Re: Worldwide YAK 50 survey (Jan Mevis) 3. 04:08 AM - Re: Worldwide YAK 50 survey (aerostar6) 4. 04:16 AM - Re: Worldwide YAK 50 survey (aerostar6) 5. 05:07 AM - Re: Re: Worldwide YAK 50 survey (Jan Mevis) 6. 09:42 AM - Cj6 engine run in (Jacquescj6) 7. 10:55 AM - Re: Cj6 engine run in (Robin Hou) 8. 11:14 AM - Re: Cj6 engine run in (Jacquescj6) 9. 04:25 PM - Re: Re-financing (keithmckinley) 10. 05:07 PM - 50 hours engine inspection (Robin Hou) 11. 05:27 PM - Re: 50 hours engine inspection (Tom Elliott) ________________________________ Message 1 _____________________________________ Time: 03:23:49 AM PST US Subject: Yak-List: Worldwide YAK 50 survey From: "aerostar6" Fellow YAK 50 owners, I am looking for help from you to build up a real world repository of experience in operating and maintaining the YAK 50. Why? I have the misfortune to live in the UK, where, as a result of the aircraft having been ex-military, and therefore uncertified, it is operated under a "Permit to Fly", system, whereby the UK CAA allow us to operate outside the fully regulated EASA regime. Unfortunately, the YAK 50 comes from the former USSR with an official lifetime of a paltry 300 hours, a legacy of its manufacture in a communist state, where it was better to employ someone to make more aircraft than to have a scheme where the longevity of the aircraft could be extended by a careful maintenance regime. Consequently, our over cautious authority, asked the Yakovlev Design Bureau, (who had no real interest in the machine after the collapse of communism, other than as a useful income stream from rich westerners) to come up with a "life extension" scheme. This has involved, at great expense, removing the wings, tail unit and engine bearers for full NDT inspection - every 100 hours! So far, to my knowledge, apart from a spar bracket crack on my machine, which was put down t a manufacturing defect, no significant findings have been found across the UK fleet of 21 airframes. I know that the aircraft are operated safely worldwide on much more enlightened airworthiness rules, and I want to tap into that experience. I, and some other owners have been trying to get the Authority to increase the time between these over cautious inspections and also to extend the next "interim life" limit of 600 hours. To this end a body of evidence proving the durability of this wonderful aircraft would be very useful in pressing our case to the feds. To this end, could i ask 2 minutes of your time to briefly list the following: Country of residence: A/c Registration: Serial: Type of Airworthiness Regime/Lifetime/Inspection period: G limits allowed: Crucially, total hours (approx) at January 2014: Any significant structural/system problems encountered over the life of the airframe. Either post on the forum, or email off list. will collate the data and publish to all when I have a decent data set. Thanks in advance, Mark and the UK Aerostars team. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418109#418109 ________________________________ Message 2 _____________________________________ Time: 03:45:26 AM PST US Subject: Re: Yak-List: Worldwide YAK 50 survey From: Jan Mevis Hello guys, My Yak 50: S/N 801807 Former RA2005K, now French "avion de collection", F-AZUK, based in France, Compiegne. I do annual inspections (the equivalent of 100 hour inspections) but the COMPLETE responsibility is with the owner. I have an official document stating that I and I alone am responsible for the maintenance. And I like that (of course I get assistance from good mechanics). G-s allowed: still +9/-6, although I never do that. Total hours since new: 318 No significant structural or system problems ever found, not in the books, not at inspection. I only had the usual minor issues like all Yak 50's (e.g. Tailwheel oleo). I don't see any reason why the Yak 50 could not be operated for much more than 300 hours, or 600 hours. Of course these planes ARE oldtimers, and should be treated like that. So if you limit the aerobatics forces to +6/-3 (or even a bit less, +5 should be enough) and if you do SERIOUS annual inspections, then they'll be good to fly for years to come. Only my 2 cents, Jan On 05/02/14 12:21, "aerostar6" wrote: > >Fellow YAK 50 owners, > >I am looking for help from you to build up a real world repository of >experience in operating and maintaining the YAK 50. > >Why? I have the misfortune to live in the UK, where, as a result of the >aircraft having been ex-military, and therefore uncertified, it is >operated under a "Permit to Fly", system, whereby the UK CAA allow us to >operate outside the fully regulated EASA regime. Unfortunately, the YAK >50 comes from the former USSR with an official lifetime of a paltry 300 >hours, a legacy of its manufacture in a communist state, where it was >better to employ someone to make more aircraft than to have a scheme >where the longevity of the aircraft could be extended by a careful >maintenance regime. > >Consequently, our over cautious authority, asked the Yakovlev Design >Bureau, (who had no real interest in the machine after the collapse of >communism, other than as a useful income stream from rich westerners) to >come up with a "life extension" scheme. This has involved, at great >expense, removing the wings, tail unit and engine bearers for full NDT >inspection - every 100 hours! > >So far, to my knowledge, apart from a spar bracket crack on my machine, >which was put down t a manufacturing defect, no significant findings have >been found across the UK fleet of 21 airframes. I know that the aircraft >are operated safely worldwide on much more enlightened airworthiness >rules, and I want to tap into that experience. > >I, and some other owners have been trying to get the Authority to >increase the time between these over cautious inspections and also to >extend the next "interim life" limit of 600 hours. To this end a body of >evidence proving the durability of this wonderful aircraft would be very >useful in pressing our case to the feds. > >To this end, could i ask 2 minutes of your time to briefly list the >following: > >Country of residence: >A/c Registration: >Serial: >Type of Airworthiness Regime/Lifetime/Inspection period: >G limits allowed: >Crucially, total hours (approx) at January 2014: >Any significant structural/system problems encountered over the life of >the airframe. > >Either post on the forum, or email off list. will collate the data and >publish to all when I have a decent data set. > >Thanks in advance, > >Mark and the UK Aerostars team. > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p=418109#418109 > > ________________________________ Message 3 _____________________________________ Time: 04:08:58 AM PST US Subject: Yak-List: Re: Worldwide YAK 50 survey From: "aerostar6" Thanks Jan. I agree, Spitfires, Mustangs and the rest are now 70 years old, were built with a forseeable life of about 6 weeks, and they are still flying with "on condition" maintenance. Can't see the difference. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418111#418111 ________________________________ Message 4 _____________________________________ Time: 04:16:40 AM PST US Subject: Yak-List: Re: Worldwide YAK 50 survey From: "aerostar6" Jan, what restrictions do you have about flying outside french airspace? Is it written permission, as it is for us now? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418112#418112 ________________________________ Message 5 _____________________________________ Time: 05:07:15 AM PST US Subject: Re: Yak-List: Re: Worldwide YAK 50 survey From: Jan Mevis Yes, it is exactly the same system: I need a permit for each other country since it's a national solution. Consequence of the EASA Annexe II rules. Usually that is no problem. BR, Jan On 05/02/14 13:15, "aerostar6" wrote: > >Jan, what restrictions do you have about flying outside french airspace? >Is it written permission, as it is for us now? > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p=418112#418112 > > ________________________________ Message 6 _____________________________________ Time: 09:42:57 AM PST US Subject: Yak-List: Cj6 engine run in From: "Jacquescj6" Hi Guys I have replaced my cj engine with a new overhauled engine. Any advise on doing the run in on the engine? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418122#418122 ________________________________ Message 7 _____________________________________ Time: 10:55:23 AM PST US From: Robin Hou Subject: Re: Yak-List: Cj6 engine run in Attached is the engine run-in procedure after replacement of cylinders.- =0A=0AHow do you get a newly overhauled engine? Do you mind sharing the cur rent market price for an overhauled engine? 1st, 2nd, 3rd or 4th overhaul? =0A=0AThanks,=0A=0ARobin=0A=0A=0A________________________________=0A From: Jacquescj6 =0ATo: yak-list@matronics.com =0ASent: Wedn esday, February 5, 2014 9:42 AM=0ASubject: Yak-List: Cj6 engine run in=0A =0AHi Guys=0AI have replaced my cj engine with a new overhauled- engine. Any advise on doing the run in on the engine?=0A=0A=0A=0A=0ARead this topic online here:=0A=0Ahttp://forums.matronics.com/viewtopic.php?p=418122#418 =========================0A ====================== ________________________________ Message 8 _____________________________________ Time: 11:14:41 AM PST US Subject: Yak-List: Re: Cj6 engine run in From: "Jacquescj6" Hi Rob Thanks will look at it. I got this one from the the person that actually imported the aircraft. I did some investigation could get 1st time overhauled engine's for round about 30 000 uS 2nd 20 000. You can ask Doug Sapp here he was also a big help. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418132#418132 ________________________________ Message 9 _____________________________________ Time: 04:25:05 PM PST US Subject: Yak-List: Re: Re-financing From: "keithmckinley" Just give me half of what you expect to spend in cash. It'll be cheaper in the long run. -------- Keith McKinley 700HS X26 Sebastian, FL Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418149#418149 ________________________________ Message 10 ____________________________________ Time: 05:07:51 PM PST US From: Robin Hou Subject: Yak-List: 50 hours engine inspection In the CJ's "Technical Specifications for Service & Maintenance", for 50 hours engine inspection on page 219, it says: "Inspect the tightness for each cylinder with a pressure gauge. Its indication should be 3.5-6 kg./cm2 under a cylinder head temperature of 40-60"C." Am I correct to assume it is not talking about a leak down test, but a compression test (like the one I used to do in my high school auto shop class)? If I am correct, 3.5-6 kg/cm2 is 49.8-85.3 psi. I recall using 100 psi as an indication for a healthy car engine when doing a compression test. The 49.8-85.3 psi range seems to be very low. What am I missing? Robin ________________________________ Message 11 ____________________________________ Time: 05:27:05 PM PST US From: "Tom Elliott" Subject: RE: Yak-List: 50 hours engine inspection The Cj eng is LOW compression That's why it can burn 70 octane fuel. Tom Elliott CJ-6A NX63727 777 Quartz Ave PMB 7004 Sandy Valley NV 89019 Cell 541-297-5497 N13472@AOL.COM From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Robin Hou Sent: Wednesday, February 05, 2014 5:07 PM Subject: Yak-List: 50 hours engine inspection In the CJ's "Technical Specifications for Service & Maintenance", for 50 hours engine inspection on page 219, it says: "Inspect the tightness for each cylinder with a pressure gauge. Its indication should be 3.5-6 kg./cm2 under a cylinder head temperature of 40-60"C." Am I correct to assume it is not talking about a leak down test, but a compression test (like the one I used to do in my high school auto shop class)? If I am correct, 3.5-6 kg/cm2 is 49.8-85.3 psi. I recall using 100 psi as an indication for a healthy car engine when doing a compression test. The 49.8-85.3 psi range seems to be very low. What am I missing? Robin No virus found in this message. 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