Crazy arse idea - swap engines . . .

I would actually have the TC aircraft inspected before purchase with the expectation of the swap - the donor airplane is located in Vegas - my Comanche specialist mechanic is in Apple Valley now - less than 45 min flight time. He knows my airplane from essentially disassembling it in 2010. He's on board - he just needs to see the donor airplane.

He finds discreps for a living. . . . I just need to convince the seller I'm serious here - I guess money in the bank gets it done - my mechanic understands the reasons and sees the benefits - the main issue is the 'little' things - like oil hoses, fuel hoses, scat sceet etc etc that will eat up any cost savings almost immediately which is my fear. . ..
 
If you are going to use an aftermarket guage for the TIT make sure it is STCed as an approved PRIMARY instrument, most analyzers are not.
 
Skylane81E said:
If you are going to use an aftermarket guage for the TIT make sure it is STCed as an approved PRIMARY instrument, most analyzers are not.
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He did mention that factory turbo'ed PA24 does not have TIT... So no STC required for that. Now replacing an OEM EGT gauge is a different story as you mention.
 
Skylane81E said:
If you are going to use an aftermarket guage for the TIT make sure it is STCed as an approved PRIMARY instrument, most analyzers are not.
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Of course, but there was no factory TIT gauge in the airplane - so primary or non-primary it does not matter. . . . original had a EGT which was replaced by the GEM in my airplane . . . . which is certified for OEM use - the EDM 700/800 series is likewise certified as primary replacement in PA24 . . . both come with a factory CHT gauge covering the #5 cylinder.
 
comanchepilot said:
Of course, but there was no factory TIT gauge in the airplane - so primary or non-primary it does not matter. . . . original had a EGT which was replaced by the GEM in my airplane . . . . which is certified for OEM use - the EDM 700/800 series is likewise certified as primary replacement in PA24 . . . both come with a factory CHT gauge covering the #5 cylinder.
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Sounds good to me
 
weilke said:
Earlier, the need for a DER was mentioned. I don't believe that that is the case for either executing a 337 based on either a TCDS and manufacturer drawing or a STC.
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That is correct -- if one of those exist, and there seems to be no evidence so far that any of them do for the engine Joe is proposing to mount. The fact that a turbocharged engine is listed in the TCDS for the specific model of PA24 Joe has does not provide what he needs if the engine off the Turbo Comanche is not the exact same engine. Further, there may be significant modifications required by the drawings mentioned. He's going to have to confirm the exact model of engine involved and then get hold of those drawings to see just what changes are needed before he can have a reliable estimate of what it's going to cost in time, effort, and dollars.
 
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Ron Levy said:
That is correct -- if one of those exist, and there seems to be no evidence so far that any of them do for the engine Joe is proposing to mount. The fact that a turbocharged engine is listed in the TCDS for the specific model of PA24 Joe has does not provide what he needs if the engine off the Turbo Comanche is not the exact same engine. Further, there may be significant modifications required by the drawings mentioned. He's going to have to confirm the exact model of engine involved and then get hold of those drawings to see just what changes are needed before he can have a reliable estimate of what it's going to cost in time, effort, and dollars.
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His plane is one of the later models that has the same engine minus the turbos. Things are pretty tight under the TCs cowling with the two little Rayjays and the plumbing attached to them, but what has to go where is documented in the STC.

I would not bank on an existing TC engine just coming apart and going back together without hickups. It may look perfectly fine while installed on the 'donor' plane, yet when you start to disassemble things, there is allways some stud that gets stripped or some crack in either exhaust or motor mount that shows up after clamps and a maze of adel clamps get removed. I dont think there will be any hangups on the paperwork, if there are problems they are going to be mechanical. My $50 is on the 'donor' plane never being put back together again because the agony of getting the 'nice' plane working and dialed in was bad enough for one lifetime.

Hence my suggestion to get a TC powerplant and engine mount from salvage. Get the engine overhauled, get all the exhaust and turbo components overhauled, check everything for fitment and completeness before pulling the 'nice' plane into the hangar. The powerplant that comes off the 'nice' plane then can go right on barnstormers to be hung onto a Comanche that someone geared up. Why deal with a whole second plane ?
 
weilke said:
His plane is one of the later models that has the same engine minus the turbos. Things are pretty tight under the TCs cowling with the two little Rayjays and the plumbing attached to them, but what has to go where is documented in the STC.
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What STC? And is the STC engine the same as the engine off the Turbo Comanche? You can't just cut and paste an STC with something else from the type certificate and have that be your approved data.
 
Ron Levy said:
What STC? And is the STC engine the same as the engine off the Turbo Comanche? You can't just cut and paste an STC with something else from the type certificate and have that be your approved data.
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The sentence should have read 'or piper drawing 27137'.

Whoever does the job also has the 'donor' plane to work off. Just take plenty of pictures. while disassembling the 'donor', keep the hardware in labeled ziplock bags etc.
 
Actually, called my mech and he has all the drawings . . . after 50 years of fixing airplanes - and he actually began working on Comanche's in 1966, 5 years before my plane was built - he knew what he needed and he's blessed that its possible. That my airframe and engine and doohiggies are in workable condition - and that most of my 3 year old fuel, oil and hydro hoses are in good condition and can be used on the new engine.

That said - he said he'd need to sign off the other one too - and that he is looking for a turbo system and housing . . . . to perhaps just rebuild mine - says he can add the manual wastegate cable with the 337 and the signoff. He also claims to have the required pages to be added to the POH he can photocopy and sign off. Mine will need a new prop - only one approved for the TC conversion is the two blade. I have a 2 blade but it has reached the end of its rope and I'm needing an engine and prop - so you can see my dilemma. Actually - the mechanic says my engine is in great shape for 1800 hours and can prob go another 1000 - but the prop seems to be reaching the end of its useful life.

Again, which is why buying the parts as an airplane seems to make more sense. Buy the whole airplane for $75k, rebuild the engine and prop for $45k? Thems alot of parts left over - seats, rails, wings, stabs, trunions [which used to be unobtanium] gear transmissions - all parts common with my current airplane.

Now, perhaps selling off the wings, the bladders, the landing gear parts, the instruments all separately might bring in more money but its 10,000 times the hassle -
 
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So you need an engine overhaul ($35k), 2 overhauled rayjays, the plumbing, the wastegates and a prop (11k) so you can do the conversion during your upcoming engine overhaul.

Buying an entire plane you'll have to part out afterwards to get parts that fit into a milk-crate sounds just like a lot more hassle than necessary.
 
Do it
Do it
Do it
Do it
Do it

If only for us to watch it all happen

:)

(There's some smart folks 'round here. I feel even more inadequate than usual just lurking in this thread)
;)
 
comanchepilot said:
Actually, called my mech and he has all the drawings . . . after 50 years of fixing airplanes - and he actually began working on Comanche's in 1966, 5 years before my plane was built - he knew what he needed and he's blessed that its possible. That my airframe and engine and doohiggies are in workable condition - and that most of my 3 year old fuel, oil and hydro hoses are in good condition and can be used on the new engine.

That said - he said he'd need to sign off the other one too - and that he is looking for a turbo system and housing . . . . to perhaps just rebuild mine - says he can add the manual wastegate cable with the 337 and the signoff. He also claims to have the required pages to be added to the POH he can photocopy and sign off. Mine will need a new prop - only one approved for the TC conversion is the two blade. I have a 2 blade but it has reached the end of its rope and I'm needing an engine and prop - so you can see my dilemma. Actually - the mechanic says my engine is in great shape for 1800 hours and can prob go another 1000 - but the prop seems to be reaching the end of its useful life.

Again, which is why buying the parts as an airplane seems to make more sense. Buy the whole airplane for $75k, rebuild the engine and prop for $45k? Thems alot of parts left over - seats, rails, wings, stabs, trunions [which used to be unobtanium] gear transmissions - all parts common with my current airplane.

Now, perhaps selling off the wings, the bladders, the landing gear parts, the instruments all separately might bring in more money but its 10,000 times the hassle -
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If I were you, I'd run this all past the Airworthiness folks at the local FSDO for review before spending any money. You would not want to find out after you do the work that your mechanic is overreaching what is actually legal.
 
So pay hangar rent for the donar plane while you try and part the rest of it out?
 
Ron Levy said:
If I were you, I'd run this all past the Airworthiness folks at the local FSDO for review before spending any money. You would not want to find out after you do the work that your mechanic is overreaching what is actually legal.
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Good idea Ron - I'll have Denny call the boys at Riverside who he worked with on the tail feathers AD. . . ALWAYS have an expert in any endeavor who knows the judge . . . no matter who the judge is or whether he is a judge or the building inspector . . .
 
bnt83 said:
So pay hangar rent for the donar plane while you try and part the rest of it out?
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No where close to where I am where that makes a lick of sense! decent idea, but anywhere in Socal - even in the desert - it makes little financial sense.
 
Hi Joe,

About 20 years ago I was involved in the conversion of a comanche 250 to a 180. Yes it seems like an odd thing but we had a 250 wreck minus FWF and the 180 came from mexico missing its dataplate and paperwork but in pristine condition. The damaged 250 was sort of a family heirloom for a neighbor and he wanted to save it in some form.

So it seemed like an obvious wintertime project. Gut the 250 and re-skin the belly. Take the FWF, wings, tailfeathers, and landing gear from the mexican 180 and move them over. Once the snow started falling we tore into it and in about 3 months had a good looking airplane wearing yellow primer and theoretically capable of flight, minus paperwork. The paperwork took another 2 months, but it's not straightwforward whether that was all due to the engine change. We had some other structural repairs that needed appaoval. We did have a DER (another neighbor) sign off on those but he didn't do anything for the engine change.

In our case both engines and all associated equipment were clearly listed on the type certificate and we were able to clearly show in the parts manual that the result was a comanche 180 in every way. We had a dozen page list of parts removed and added and we weighed the plane when we were done.

My biggest concern with your proposal would not be the paperwork, that can be navigated. It would be the number of 3rd party man*hours you're going to pay if you are not doing the work yourself. A job like this is best done as a labor of love, not as a hired enterprise.

In any case it sounds like your idea makes no sense, just like ours, and it sounds like yours would be a lot of fun just like ours was. Good luck.
 
Skylane81E said:
I'll fly the donor afterwards till you sell it:lol:
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Believe it or not I'd already have a buyer . . . . a 260C is not that hard to sell for the right price. . . . a friend who lives in Alabama and presently has a wife, a 14yr old daughter and 7 yr old son and a Mooney - and in about 2 years is going to need more payload. . . . I brought this up to him and he said he's buy if it gets signed off by my guy - knowing its gonna need a rebuild shortly - in fact he may pay for it when the engine is off since take off and put on would be on me . . .
 
comanchepilot said:
I think there would be line out the door for a Comanche 260C - normally aspirated priced as a run out - right around $60k.

There are not many 260C's for sale ever - the only ones that remain for sale are the ones priced over $100k which is crack smokin' jones territory.

You could wholesale the flying airplane for $50k - and have a line out the door and still save $10k and get a turbo in the process . . ..
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60k can buy you a sweet V-tail Bonanza. With good times. I think that's where the line would be.
 
wjgesq said:
60k can buy you a sweet V-tail Bonanza. With good times. I think that's where the line would be.
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You'd think that, but a C-model Comanche is amazingly resilient in price and market.
 
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