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Avid--VW combo.

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Posted

I've noticed the VW derived engines are not popular with A--KF. Builders, mainly because of weight and or cooling . But because the price of the favored engine jumped about 40 percent while I was dealing with wings etc. I decided, with Dean Wilson's oversite we would bite the bullet and see if we could make a decent effort using a 2180 Revmaster from an abanded Q2 project. One of the mods we made. Mounted the engine direct to airframe about 2" behind the original firewall, as adding weight is almost the unpardonable to my mentor. Built a carbon fibre cowl. Anyway, a few progress pics. As a first time builder, this forum is great. Also welcome any suggestions . Jackpost-546-0-63418000-1390544018_thumb.jpgpost-546-0-69696900-1390544159_thumb.jpgpost-546-0-70834700-1390544291_thumb.jpgpost-546-0-52213400-1390544486_thumb.jpgpost-546-0-43610200-1390544591_thumb.jpgpost-546-0-69682000-1390544695_thumb.jpg

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Posted (edited)

Jack,

       Guessing from your photos - this is a direct drive?  These have seemed to perform poorly for STOL planes - A redrive will double your torque and allow you to use a full-size prop - I know they make redrives for the VW, and they add weight, but there are performance benefits too.

Keep us posted on weights, CG, performance, etc.  Sounds like you got a good "helper" there.

I wonder what Dean would say about me extending my leading edge 4 inches to balance my Subaru w/redrive?

And, splitting my flaperons into 6.5 foot 45 degree flaps and 6 foot differential ailerons, each 14 inches wide, using the Steve Wittman tube-in-a-tube control design?

EDMO

Edited by Ed In Missouri

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Posted

Wow, Jack that cowl looks nice.  I flew behind a Revmaster  in my Q-2 for a few years and have a few suggestions about them.  The Posa carb works Ok after some setup tweaking and there is some good info about that available on line.  Also there is a mandatory safety mod that adds a setscrew to the needle to keep it from turning in flight.  I think I still have the info in my files if you need that.  It is an easy mod to do but important.  The heads supplied with these 80's model Revmasters were junk and they cracked between the valves.  The good news is that the new heads breathe  better and offer at boost in horsepower.  Most users replace the supplied oil filter with an automotive filter that saves weight and gets rid of the mess of cleaning the Revmaster filter.

 

I built some cooling ducts that kept the heads cool and also there are some things called "Cool Tins" that fit under the cylinders that help cool them evenly.  Head cooling is a problem with the VW so make sure to use CHT's.

 

Head bolts must be checked every 25 hours and the valves adjusted also with the oil change.  There have been some accidents caused by loose head bolts on VW based engines.  With the Cooling ducts like the Jabiru  my heads ran cool and the head torq stayed good for the most part.

 

The oil cooler requires a separate, dedicated opening in the cowl and ductwork to direct the air over the oil cooler, without it the temperature of the oil will redline within minutes.

 

There is an AD on the magneto impulse coupling that you will want to do also that is easy to do yourself with a file.

 

There is a video or two of a fellow in S. America I think, that is running a Revmaster in an Avid that is interesting. 

 

I will send a personal reply to you with my cell phone if you have other questions.

 

Looks like you are doing a great job with your install.

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Posted

Paul,

     Didn't someone make water-cooled heads for the VW?

EDMO

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Posted

I bet someone did Ed, I know that you can get them for the Jabiru.

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Posted

I have over 200 trouble free hours behind an aircooled VW 1600. I don't have an oil cooler and used to fly it in Phoenix even when the temps were over 115 degrees outside. Never had a problem with it cooling. The cool tins that cover the lower part of the cylinders and some type of well made shroud (much like an older Piper cub) will work wonders on these engines. You can not fly them with these or they will overheat. Just stick the heads and cylinders out in the air and they cool wonderfully.

I can't vouch for what they'll do when you cover them up with a pretty cowling though. My plane isn't big enough to have such a critter mounted on the front of it. The engine is the widest part of the cockpit and fuselage.

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Posted

Paul,

     I was thinking that Revmaster, or one of the major VW makers, had a redrive listed in the Kitplanes engine buyers guide.

I don't know that much about who is making them.  I did read some about doubling torque and slowing down prop so you could swing a larger prop and get STOL performance out of them.

EDMO

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Posted

Valley Engineering builds a redrive for the VW's. If you're looking. I don't know much about them other than I checked into their ultralight engine a few years ago.

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Posted

Thanks guys for the feedback, and Paul I did get the info on the Posa . For now we'll continue with plan A and see what we come up with. Thanks. Jack

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Posted

Sorry you had to do lazy 8s to look at the pictures.

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Posted

Feb issue of Kitplanes about Airdrome Aircraft (WW1 replicas) stated that with the direct drive VW they could only pull a 60" prop - Direct drive had 200 lbs pull, but by using Valley Redrive, increased that with larger prop to 400 Lbs pull.

EDMO

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Posted

There is an early Flyer (A or B model, I think) at the Big Lake airport that has a VW powerplant. Years ago I had talked with the owner. If I remember correctly he was claiming somewhere around 100 HP, and on the heavy side for the airframe. I don't know if it is in flying condition any more.

 

 What was really interesting was the leading edge of the wings; they had an extension that came forward and down from the stock leading edge. There was no slot like on a slat. Odd looking, and I can't know what exactly it did. A friend had seen it fly on floats and was impressed.

 

-Nate

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Posted

Nate,

      according to what I read (Barnaby Wainfain) that this extension let his CG come forward to balance the VW - probably with redrive -  as far as the downward angle goes - again, BW says that the forward undercamber does not affect nose-down moments as much as a downward slope of the trailing edge - read all that as Undercamber.

EDMO

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Posted

Nate, I think it's an a model.. But far from airworthy at this time. I have been eye balling it since about 07 and it has not moved. Here are a few pics I snapped of it last year when I was hanging around the airport after my helicopter ride outta the swamp.

:BC:

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Posted

 It's aged since I looked at it! It was probably 1999 or 2000 when I talked with the builder. It's probably just coincidental, but the cowling reminds me of the nose from an Avid Amphibian that has been modified. This plane probably was built before Amphibians.

 

 Then there's that shortwing in the background; looks like it hasn't flown in awhile either. Or maybe he just parks in the weeds because it's cheaper  :)

 

-Nate

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Posted (edited)

I wonder if the builder is afraid to sell because of liability?  There has never been a judgement against an amateur builder like there was in that crazy suit against Piper, as far as I know.  Maybe he would sell it for "parts"?

     This brings up a question - my buddy says a plane cant be sold, or left to a wife or child, if the owner dies, because it has no "title", and it is only "registered" in the owners name.  

His lawyer said he had to leave it in a "Trust", but this same group would not make out a simple will for me without a complete investigation into my finances, properties, etc., for which I declined to do.

     I think there should be a way - if not, then my widow can just sell mine for "parts" - but don't guess you can do that with a certified factory plane.

Any attorneys on here?

EDMO

Edited by Ed In Missouri

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Posted

The guy wanted 25k for the piper a few years ago when I wanted it for parts... Yikes! It's way beyond airworthy and needs a complete tear down n rebuild!

That leading edge on the avid scared the shit out of me when I looked at it..

:BC:

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