Lower rpm 2180

[blane.c]

WOT is about 3400 rpm and 94 mph.

About 39hp?

 

[Bill-Higdon]

I think the idea of a larger displacement, lower RPM VW conversion has a lot of merit. I have given it some thought already, myself, as a potential powerplant for some of the airframes I'm interested in. I agree with Pops, the stock VW cam is great for our RPM range, with valve timing events that are pretty close to what you'd find on a Lycoming cam. If more lift is needed, you could change to 1.25 ratio rocker arms without much fuss. A couple of other good candidate camshafts are:
Eagle Racing Type 1 Camshaft, 2231 Grind (Cheater Fuel Efficient Series), 1.1 or 1.25 Rockers, CB2231 - Volkswagen Aircooled.Net VW Parts
248-54F Volkswagen Type 1 Solid Lifter Camshaft

I seem to remember Bob Hoover talking about a "Chugger" cam, but I don't recall seeing the specs on it

 

[JohnB]

I seem to remember Bob Hoover talking about a "Chugger" cam, but I don't recall seeing the specs on it

My VERY defective memory keeps whispering "ENGLE" but no identifying info to go with it.

 

[Pops]

My VERY defective memory keeps whispering "ENGLE" but no identifying info to go with it.

Yes, Bob Hoover did talk a little about a "Chugger" cam but never gave any details that I know about.

 

[rv7charlie]

I prefer the old Valley Engineering technique; just use a light weight reduction & swing a really big prop. Unfortunately, after Gene passed away they discontinued everything and all the info disappeared from their website, but here's a pic of their VW powered monoplane:


That is an 8 foot diameter prop on a VW (with reduction drive, of course). Anyone who hung around the UL area of OSH back in the '90s saw this a/c eat alive every other light plane on the field (other than helicopters).

Minimal bending loads on the crank (gyro loads reacted in the prop shaft; only the bending load of the belt), and lower BMEP in the engine, meaning lower loads all around internally.

You do need enough landing gear length to swing it, of course.

 

[103]

Yes, Bob Hoover did talk a little about a "Chugger" cam but never gave any details that I know about.

I have 25 years of email with Bob this snip is 2005 upstream it was a Schneider 248-F for his Stroker recommendation and stock for all else. Education beyond the question was a sure thing!

 

[rv7charlie]

Hey Blane,

Is this the software you're using? How well does it 'scale' from models to full size a/c? Also, is there any provision for different airfoil selection, blade planform, how/where pitch is measured on the blade, etc?

 

[blane.c]

Hey Blane,

Is this the software you're using? How well does it 'scale' from models to full size a/c? Also, is there any provision for different airfoil selection, blade planform, how/where pitch is measured on the blade, etc?

I am playing with it. The top six items are user inputs and the rest are calculated, you can choose metric, American, or knots and degrees/radians

 

[karmarepair]

I think the idea of a larger displacement, lower RPM VW conversion has a lot of merit. I have given it some thought already, myself, as a potential powerplant for some of the airframes I'm interested in. I agree with Pops, the stock VW cam is great for our RPM range, with valve timing events that are pretty close to what you'd find on a Lycoming cam. If more lift is needed, you could change to 1.25 ratio rocker arms without much fuss. A couple of other good candidate camshafts are:
Eagle Racing Type 1 Camshaft, 2231 Grind (Cheater Fuel Efficient Series), 1.1 or 1.25 Rockers, CB2231 - Volkswagen Aircooled.Net VW Parts
248-54F Volkswagen Type 1 Solid Lifter Camshaft

Even better for low RPM is the Schneider 248 248-54F Volkswagen Type 1 Solid Lifter Camshaft developed for wind machines used for freeze protection in orchards (citrus, avocado) in Southern California. A VW engine (complete with fan, shroud) with a prop on a pole, started by remote control. Use ratio rockers if your big displacement (limit stroke to 78mm or less and you don't need to clearance the case) engine needs the valve lift.

 

[Saskguy]

Wow lots of responses here with information beyond my current knowledge. Looks like I have some reading and research to do about camshafts and manifold pressure.

 

[cluttonfred]

I prefer the old Valley Engineering technique; just use a light weight reduction & swing a really big prop.

Ace Aviation in India offers redrives capable of handling up to 85 hp (for the Gaokin 1000cc ATV engines). I don't see why someone couldn't work out with them the correct adapter plate and crankshaft connection for a VW belt redrive. It would run about $1,300 delivered to the USA.

 

[rv7charlie]

Their prices certainly seem 'right'. I wish there were more hard data available on operating characteristics, particularly with the 4-stroke V-twins & inline twins. Stuff like minimum idle rpm, etc. Virtually every other drive mfgr has had to do something to handle torsional resonance issues at low rpm; either a clutch of some sort or, like the Valley product, a spring loaded damper mechanism. What's the 'magic' that removes the need with this drive? Also would be nice if they included all the stuff needed to make them work ('Shaft lock bush NOT included'), or at least supply a brand/part number for what you need to purchase.

 

[Bille Floyd]

Ace Aviation in India offers redrives capable of handling up to 85 hp (for the Gaokin 1000cc ATV engines). I don't see why someone couldn't work out with them the correct adapter plate and crankshaft connection for a VW belt redrive. It would run about $1,300 delivered to the USA.

Their redrives for engines Up to 32 hp ; any idea what
something like that would weigh ?

Bille

 

[cluttonfred]

Their redrives for engines Up to 32 hp ; any idea what
something like that would weigh ?

It’s all there in the link, the 32 hp redrives are listed under GX390/420.

 

[Vigilant1]

Their prices certainly seem 'right'. I wish there were more hard data available on operating characteristics, particularly with the 4-stroke V-twins & inline twins. Stuff like minimum idle rpm, etc. Virtually every other drive mfgr has had to do something to handle torsional resonance issues at low rpm; either a clutch of some sort or, like the Valley product, a spring loaded damper mechanism. What's the 'magic' that removes the need with this drive?

When John of Ace chimed in here, he did not provide information about the Ace drives and torsional resonance. (More here following billski's post.)
It was almost as though he is selling the drives to customers without having looked into this.
The primary response seems to be: "Our drives aren't failing in use."
If Ace is relying on paying customers to be beta testers/test pilots, they certainly wouldn't be the first company to do so. But it seems to me it would be proper for them to collect data on their "test fleet" so prospective customers will know if any of the claimed satisfied existing customers have the same engine, redrive, and prop as the one they plan to use, how many hours it has accumulated, and what their experience has been. Sure, it would be extra work for Ace, but at least their "they are working in use" claim would have useful substantiation.

 

[daveklingler]

Even better for low RPM is the Schneider 248 248-54F Volkswagen Type 1 Solid Lifter Camshaft developed for wind machines used for freeze protection in orchards (citrus, avocado) in Southern California. A VW engine (complete with fan, shroud) with a prop on a pole, started by remote control. Use ratio rockers if your big displacement (limit stroke to 78mm or less and you don't need to clearance the case) engine needs the valve lift.

Is the Schneider 248-54F the same as the Schneider 248F that Bob Hoover talks about in 103's post about a half hour before yours?

 

[karmarepair]

Is the Schneider 248-54F the same as the Schneider 248F that Bob Hoover talks about in 103's post about a half hour before yours?

Yes.