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Backcountry Pilot • Super Stinson conversion complete

Super Stinson conversion complete

Have you modified your aircraft? STC? STOL Kit? Major rebuild from just a data plate?
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Super Stinson conversion complete

9393K made the first test flight yesterday with the new engine and all went well. Took my IA and an airframer a little over three weeks to complete the conversion including updating the electrical system and installing a vacuum system. Mods to the cowl were reportedly the tricky part. Initial performance shows that it'll run to VNE S&L and climbs around 2k ft/min. Useful load has predictably shrunk, but nothing in life is free.

http://picasaweb.google.com/Andrew.McVi ... sonProject
Vick offline
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That's a slick paint scheme, I really like it. Cool pics Vick.
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Thanks Z, last thing is to tidy up where the paint lines don't match up anymore on the cowl.
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Great documentation on a big project. Congratulations, it looks REALLY nice, and I'm sure the performance is everything you hoped for. The 470 R is a great engine.

You might want to add some foam pipe insulation on that forward induction crossover tube. On Cessna 180's, it's really hard to get them to run smooth in cold weather without that forward tube insulated. It's not hot there, so just put some of the split lengthwise pipe insulation on it, and tie-wrap it in place. It may not be necessary on the Stinson, but it really is on the 180 with this engine.

Good job, and you need to buy those mechanics a nice Christmas present--they did a really slick job.

MTV
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I'm impressed! A chain saw as a aviation tool!

Nice pictures. Looks like a great job! That is going to be fun to fly! Good luck.
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mtv wrote:You might want to add some foam pipe insulation on that forward induction crossover tube. On Cessna 180's, it's really hard to get them to run smooth in cold weather without that forward tube insulated. It's not hot there, so just put some of the split lengthwise pipe insulation on it, and tie-wrap it in place. It may not be necessary on the Stinson, but it really is on the 180 with this engine.

MTV


I'll second that, but I would suggest using the same firesleeve that you used on the crankcase vent tube, just in case. I put that on my 180 after the first couple of years and it did make a difference in winter ops. The other thing that I routinely do with the 470U is pull the throttle back about half an inch to set up a little turbulence in the induction tubing that helps get more even mixture distribution. If you have a six probe EGT/CHT, it's easy to see the EGT's change as you pull the throttle. Usually doesn't take more than 1/2 inch of manifold pressure although in some circumstances full throttle seems to have better mixture distribution. I never have figured out why. This will also let you lean more aggessively at higher altitudes. At some throttle settings and altitudes I can even run a few cylinders lean of peak smoothly. YMMV!

I also use some carb heat in cruise below about 30 OAT, but you must have a carb temp gauge to do this safely, or you might just get the carb into the icing range from below it.

What a rocket ship! You should try talking AOPA into doing a better than new Stinson! :D

Rocky
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I can't recall AOPA ever doing a make-over/give-away on a tailwheel airplane. Shame on them.
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zero.one.victor wrote:I can't recall AOPA ever doing a make-over/give-away on a tailwheel airplane. Shame on them.


Oh yeah, right..... sometimes I forget that 90% of the pilot population can't fly tailwheels! :twisted:
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Actually, a couple of years ago, AOPA did a rebuild on a Waco biplane to give away. That project is what got Boyer interested in Wacos (he got a tailwheel endorsement in the Give-Away plane) and now he owns one.

MTV
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Thanks to all for the feedback, the guys who did the work on this put a lot of effort into it and I think it shows. There was a lot of fabrication and fitment required in areas that aren't well addressed in the STC. Thanks too for the input regarding insulating the crossover tube, I asked my IA about it and he is going to get me a chunk of insulation.

Now I just have to get a window of decent wx so I can make the second attempt at flying it from NC to CA. Should at least be a little bit quicker trip now though!
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Way to go Vick. I can't wait to here your reports.

How much does the STC run for that conversion, and the engine your AI has for sale, it is a rebuild? I have been thinking about this conversion.

I have a bit of a green patch going here!

Go for it.
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Looks great Vick, you'll love it! You're right, there is a few areas in that STC that leave a bit of slack..but nothing major. Everyone that I know that has that conversion loves it, and every one I've done has resulted in a happy customer!
John
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Higgy - The STC runs about 9k, but that includes the mount, exhaust, and a big pile of other parts. Then add in engine (w/accessories), prop, governor, and another pile of necessary parts. Labor, and John can chip in with his experience here, is 40-50hrs to set up the engine and another 40-50hrs to do the metal work. When they did the work on my plane they ended up doing what others told me to expect - gen to alt conversion with appropriate wiring upgrade, venturi to vacuum system conversion, etc, etc. I kept getting the phone call, "Since we're in there we really should..."

John - Just saw the pics in your gallery of your recent 470 project, looks amazing! Ground up is the way to go to get it right. Mine looks OK from 20ft, but I would have preferred to go all the way through it. Someday... Your aux tank looks great as well, looking forward to hearing that your STC is available. I'm running an 82" McCauley - in your experience how much prop clearance have you ended up with? I think I've got something just over 20" right now (3pt attitude of course).
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