Geshwender PSRU Business

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lganderz

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Does anyone know what happened to Alternate Airpower run by John Worden, who continued manufacturing Geschwender PSRU designs after Fred Geshwender died?
 

J Galt

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I tried to get ahold of him about the business, to no avail. If you hear anything or if anyone here knows him please put us in touch. There is a company making a PSRU using a Hyvo chain but they don't sell it separately and don't mention if it was the Geschwender design.
Justin
 

lganderz

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Good news! I found the gentleman that bought the Geschwender PSRU business from John Worden (alternate-airpower.com). His name is: Larry Buchanan and he can be contacted at: (626) 641-9034 or [email protected]. He said the inventory he bought could build several of the PSRUs and is open to discussions about supplying them.

BTW, he has built a scaled replica of the P-38 with a 38 ft wet-wing that should go non-stop from LA to Honolulu. Next step is building molds off of the prototype so he can supply kits. If anyone find this interesting give him a call.

Leo A.
 

lganderz

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Outstanding! Good work :)
Justin
Justin:

I recently bought the assets of the last company that built the Geschwender PSRUs (Alternate Airpower). I'm trying to assess if it is worth the effort to put this product back in production or just build one for my aircraft. Any thoughts on the market demand for this product?

Leo A.
 

wsimpso1

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Justin:

I recently bought the assets of the last company that built the Geschwender PSRUs (Alternate Airpower). I'm trying to assess if it is worth the effort to put this product back in production or just build one for my aircraft. Any thoughts on the market demand for this product?

Leo A.
Market Demand? Do not know...

The engines favored seem to be GM LS-3 and relatives. There are a few products currently out there. This retired transmission engineer's take on what is out there:
  • Geared Drives - Intended for airplanes, low end of LS-3 power, the drive is big/complicated/expensive, but drives a hydraulic constant speed prop, seems to have units flying and being readied for flight. There have been a couple of notable failures, one by the founder, and another by a customer accused of (gasp) maneuvering the airplane;
  • Ballistic Drives - Intended for airboats, reputed to be bullet-proof even with really big props and enhanced engines, no provision for a governor;
  • AutoFlight - Intended for airplanes, mostly used on Titan-51, appears to be limited to modest power only, has had some notable failures;
There are other airboat drives for big V-8's also out there. In all cases, I would advise searching the internet to give you more info on data and histories of each of these.

My suspicion is that the market is real and that a really reliable drive with provisions for a hydraulic constant speed prop could take over from the other guys. How big? I have no numbers, but Geared Drives keeps showing up at the conventions and AutoFlight keeps supplying the T-51 guys, so there must be enough for them to bother, and they are the opportunity for a really reliable drive. If a really good option showed up, it might expand the market for LS powered homebuilts.

Billski
 

tspear

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@wsimpso1

Why not an electric constant speed prop?
I know they are/were popular with lower powered engines. Seems like it would be a lot less complicated to my very limited knowledge.

Tim
 

rv6ejguy

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There is also the CAM drive being used on the LS powered Moose, Robinson Hy-Vo and the Marcotte M450. Lot's of choices, none are cheap or light.

Would take a while to create a significant market here for yet another choice. The Geschwender is also pretty heavy I have heard, being used in some Ag planes mostly where weight didn't matter so much as they were replacing heavy radial engines.
 
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rv6ejguy

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@wsimpso1

Why not an electric constant speed prop?
I know they are/were popular with lower powered engines. Seems like it would be a lot less complicated to my very limited knowledge.

Tim
These work just fine for most cruising type aircraft. Dozens of my customers using MT electrics. Not so good for aerobatics.
 

wsimpso1

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@wsimpso1

Why not an electric constant speed prop?
I know they are/were popular with lower powered engines. Seems like it would be a lot less complicated to my very limited knowledge.

Tim
Only one supplier of electric constant speed props, and their stuff is expensive compared to the competition.
 

rv7charlie

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Only one supplier of electric constant speed props, and their stuff is expensive compared to the competition.
There are actually several from around the world now, but all have the same dollar$ problem.
The upside to hydraulic props is that there are a lot of them out there, they're 'faster' (not airspeed, but pitch change), they're relatively standardized in fit/weight, and because there are a lot of them out there, used ones are frequently available for a lot less money.

One upside to the chain drive is that it turns the 'right' direction. Most of the airboat drives are 2-gear systems that reverse prop rotation. You might think that finding left turning props for these 300+HP engines would be easy, but it ain't, unless you're willing to pay 'new' prices. I've got a friend who's been searching for left turning blades for literally years.

I'd love to know what the Geschwender weighs, if you could share the info.

Charlie
 

Aviacs

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One upside to the chain drive is that it turns the 'right' direction.
Out of sheer curiosity:
Assuming electronic ignition and a "reverse" oil pump if necessary, are modern automobile engines sufficiently biased in the rest of the geometry to preclude ordering a custom cam for reverse operation? Bearing thrust issues with helical gears in the cam drive train? Tappet bore offset to cam centerline? Or?

If engine architecture permits (perhaps a big if??) my impression was that custom cams used to be fairly cost effective, especially compared to prop blades.

smt
 

rv6ejguy

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Most engines use offset piston pins as well, so these would need to be turned around. Many newer engines use oil pumps driven directly off the crank so that presents more problems, ditto some water pumps.
 

rv7charlie

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Used to be common practice 50 years ago, in the automotive based V6s & V8s of that day. No idea about today's LS motors, etc.
 

Aviacs

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Most engines use offset piston pins as well, so these would need to be turned around.
Thrust face of piston remains the same, so no change there.
However, if the cylinder bores are biased to crank centerline, that might create issues.
If CL of bores are radial to the axis of crank rotation, there should be no problem.

Nonetheless, it is a question. I simply don't know what large modern V engine architecture entails.

No doubt if it was that easy, people would be doing it. :)

smt
 

rv6ejguy

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When we reverse direction on engines like the Corvair, we turn the pistons 180 deg if they use offset pins. That's easy to do as the engine will be apart anyway.

MT will build any prop for you for a price. In any case, you can use a chain, Marcotte or 3 gear spur type to retain same prop direction if you have to use an existing prop.
 

piepermd

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Justin:

I recently bought the assets of the last company that built the Geschwender PSRUs (Alternate Airpower). I'm trying to assess if it is worth the effort to put this product back in production or just build one for my aircraft. Any thoughts on the market demand for this product?

Leo A.
Hello, Leo

I have a Geschwender PRSU and am wondering what the horsepower rating might be. This is one of the units for the Ford 400 motor. If you have any drawings or other detailed information I would be happy to pay you a consulting fee! Thanks.
Justin:

I recently bought the assets of the last company that built the Geschwender PSRUs (Alternate Airpower). I'm trying to assess if it is worth the effort to put this product back in production or just build one for my aircraft. Any thoughts on the market demand for this product?

Leo A.
 

Lendo

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I remember Butch (Engineer) who developed an Electronic Constant Speed prop actuator, but I lost touch with him when he was hospitalized. Anyone know what happened to him or his development - it looked very professional.
George
 
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