Posted 22 Mar 2023 I picked up an AVID last week. The plane appears to be a "C" Model extended speedwing. . .062 spars, 3/4 inch lift struts. HAs "B" model cowl, radiator on the side.The airframe seems to be in good condition, does not seem to have much wear. It has been flown little, if at all. No registration, no logs. It apparently had a Rotax 532 on it at one time.At present, there is a HAPI (VW) engine mounted on the airframe. I believe it is a 1600. There is little evidence that it has ever been run on that airframe. For certain it has never flown in that configuration, as the instruments and controls are more appropriate to the Rotax. I'm still evaluating what I have.Has anyone actually flown an AVID with a HAPI on it ? Present plan is to build an engine test stand and see if I can get the HAPI to run mostly out of curiosity. Before that I will do a Weight and Balance. Probably wind up with a ROTAX 582 on it.Looking for information. Thanks Bob McCaaAvid N5113H; Avid 533SE Share this post Link to post Share on other sites
Posted 22 Mar 2023 No Avid/VW experience but flew behind a Rev master 2100 in my Q2 for a few years. HEAVY,HEAVY AND HEAVY. WHEN I removed the engine from the plane it weighted 200 lbs without oil not so great for 65 hp. Hapi had issues also. I would not waste much time messing with that engine and just put the Rotax back on it but that’s just me. I’m guessing the w/b will give you enough info to make your choice. Seems like there is always a bit of a market for those old VW engines. Share this post Link to post Share on other sites
Posted 23 Mar 2023 If you do decide to try the Hopi here are some thoughts that might help. Cooling ducts are a must to cool the rear cylinders (jabiru style easy to make) Torq the heads every 25 hrs Adjust the valves every 25 hrs Oil temps big issue so a well ducted oil cooler is importantfeel free to contact me if you have questions. 1 person likes this Share this post Link to post Share on other sites
Posted 24 Mar 2023 The Posa is very fussy to setup. Hopefully the one you has has mixture control. Some of the early ones did not and I would not waste any time on those. Here is a link for setting up the Posa.https://authorzilla.com/pyBMN/the-posa-carb-instructions-great-plains-aircraft.html Share this post Link to post Share on other sites
Posted 21 Apr 2023 you can find a lot of threads here about how crummy the performance is, poor rate of climb etc. However this guy doesn't seem to have much problem.https://youtu.be/nRWzKMYz9eA Share this post Link to post Share on other sites
Posted 21 Apr 2023 Where I'm at right now/ I have borescoped the engine, and the interior is clean as a hound's tooth. Compressions are over 110PSI on the starter. Oil pressure on the starter 25 psi.To this point I still have no idea what engine I have. There is a new set of spare pistons/jugs that are marked 91.95. I( have to look into the engine again with the borescope to see what's in there.I have the test stand nearly done, and as soon as I fabricate an instrument panel for it, I will run the engine up on the test stand. I fabricated an intake system "Y" pipe out of schedule 40 PVC to test it and get dimensions, , but a buddy came up with the intake system off a Great Plains that will fit. If I can find a local metal fabricator that can mandrel bend thin wall, I'll copy it.I did a W&B on the plane, and it weighs 540 lbs dry, but the c.g is at 9" behind the leading edge, which is too far forward. I expected that.Plan is to run the engine on the test stand, then deal with the airframe. I recognize that it may be a one person airplane, but in over ten years, I have flown a passenger less than a dozen times anyhow.Despite what was claimed, I am relatively certain that the plane is actually a "B" model extended speedwing. It has an offset rudder, a side radiator, and ASUZA wheels with mechanical brakes. Also 3/4 inch lift struts. Probably 950 lbs gross. Share this post Link to post Share on other sites
Posted 23 Apr 2023 I think it might be pretty heavy requiring weight in the tail to bring it into balance. Useful load will be compromised. Share this post Link to post Share on other sites
Posted 20 Jun 2023 Those 92mm pistons with a stock stroke of 69mm makes an 1835cc. That configuration was very popular with the bug crowd years ago. When I built my bug I used 90.5 for 1755cc. The outside dimension is the same as 92 so I have thicker cylinder walls.There are tons of hot rod parts for VW out there but most of them make the horsepower at higher RPM which won't work well for a plane without a reduction unit.Keep us posted. Share this post Link to post Share on other sites