Author Topic: Engine choice - Cabin Eagle  (Read 5839 times)

Offline Kiwi55

Engine choice - Cabin Eagle
« on: March 06, 2017, 08:17:20 AM »
I'm getting close to the point of having to make a decision on an engine for my Cabin Eagle.
I'm not going for a minimalist option, I want starter and electrical system.
I am considering the following:
1. Direct Drive VW, probably 2180 cc and probably from Great Planes (if they respond to me email).
     Pro's, that's what the CE was designed for, probably the cheapest option, much cheaper to overhaul. Con's, I'm not convinced that direct drive is the best option, may     be marginal with a full load.
2. Redrive VW, again probably 2180cc and from Great Planes
     Pro's, Better use of engine power, More prop options. Con's, More weight, more money
3. Rotax 912, would have to be a used/rebuilt engine
    Pro's, Lighter, better use of engine power. Con's Probably more expensive to buy, much more expensive to overhaul, may be difficult to find at a suitable price when I need it.
4. Aeromomentum AM13 (Suzuki engine converted to aircraft use)
    Pro's, weighs about the same as VW with redrive, more power, modern technology with fuel injection and FADEC, in the upright version costs $8995, all new. Con's, all new, upright version might be too tall, low profile version $10,995.
5. Others? Any recommendations?
Is it feasible to install a direct drive (pulley end) VW and later add a redrive?

Offline PropMan

Re: Engine choice - Cabin Eagle
« Reply #1 on: March 06, 2017, 08:39:06 AM »
How about A Radial? Less than 130lbs installed, 65 HP @ 2300 rpm, less than 9000.00. You would need extended gear for prop clearance, 70-72" dia prop

Offline Tom XL-7

Re: Engine choice - Cabin Eagle
« Reply #2 on: March 06, 2017, 09:35:00 AM »
Would like to add a "con" to your list. 
Any re-drive: something else that fails.
  I know of an aircraft that had a re-drive issue in the first 10 hours of test flights. That was a lot of work and money to throw away. No one was hurt.
Just as why are most aircraft air cooled. You eliminate a water pump, hoses, clamps and a radiator or two.  
 The VW has an rpm on the upper range of direct drive props. I get why you want to throw a larger prop slower.  ( as well as clearance). It's not like you can crank the rpm up for more power without dealing with the heat issues. I think there were some late model buses that had water cooled heads. It just keeps getting heavier and more complex.
Tom XL-7
I have a 4A-084, Barn fresh!
and a line on a 1/2 VW, dual plugs, scat heads, cheap $2000, 40 hp lightly used by an old man who is no longer living.
That 3 VW Verner still looks awful nice.

Offline Kiwi55

Re: Engine choice - Cabin Eagle
« Reply #3 on: March 06, 2017, 12:25:39 PM »
The Verner Scarlett 5VW at $8150 looks very interesting. Weight also looks great.
Anyone have real world experience with them?

Offline MrG

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Re: Engine choice - Cabin Eagle
« Reply #4 on: March 08, 2017, 02:32:54 AM »
First choice is the VW i have 35 + hrs on this ( 2276cc 94 bore x 82 stroke 8.22:1 on Avgas) and it runs and starts so sweet - using a Bing 64 Carby and you need to at least run the Great Planes Crankshaft no matter who builds it. (sorry Aero Vee Suck) can't say any thing good about them -  CB performance ( CA ) does great deals for part if you need to and what we use here in Australia ( Through Rod Penrose Racing )

it works with Frank's Prop ( o i love that prop ) and if engine assembled properly and serviced will run forever.
Mine is turn key with the Geni Pod to charge the battery ( Jim Hardie ) as long as you do longer than 25 minute flights it will stay
charged. 100% worth it

2 Choice
i had the chance 12 months ago why in texas to visit Frank and see the 3 cyl radial - If i had the money i would very closely have a look at the bigger radial  i dont know how W/B will go with the 5  - i did think Frank may of said the 3 cyl may develop enough torque for the DE ???

Rotax is lighter than the Verner but $$$ "Its a great package" if you wanted a 25 thousand dollar CE/DE ( but its a great choice if i had the money i would of done this)
flow behind one for many hrs

I develope more HP than the 2180 in my DE and glad i did,   3150 rpm  i'm around 64 knots & climbs on a cool day @ 800 fpm (it gets some good comments)- Would not swap it for less HP
we run the bing 64 carby and spent may hrs tuning it to make it work and they are in my opinion are "the best choice" my neighbour has a OneX he tried there carby/slide bar
then swapped to the Aussie made TBH copy by Rotec, then after flying the DE walked inside and rang the distributor for Bing here and ordered one to put a Bing on his OneX
and loves it too

Last Rant
No i would not use a redrive  the aerodynamics don't work with the thrust line and prop size and on and on - personally the plane at 60/65 knts is near its limit for the design
the lines don't match speed and to spend money to go faster there's better places to gain than add HP due to the maths of drag - im waiting the out come of the redo of the
fuse of rfeenstra's mods - to see what he if or what gains - cheaper to re do the fuse that pay for HP and fuel
Just my AUD 3 cents (USD $0.02)
It runs just as good on 95 Oct Car fuel,  can't see any difference
Temora Airport  Australia
1st Aussie DE built/flown
1 Oct 2015 First Flight
Feb 2019 - 155 hrs Flown
March 4th removed from service for Cabin Mods

Offline Kiwi55

Re: Engine choice - Cabin Eagle
« Reply #5 on: March 08, 2017, 06:53:06 AM »
I appreciate the information, most helpful.
How does the VW perform at gross weight? Can you comfortably carry a full size passenger?
Also could I get the spec's of the propeller you are using?


Offline Tom H

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Re: Engine choice - Cabin Eagle
« Reply #6 on: March 09, 2017, 06:41:44 AM »
Kiwi, this may help answer your questions:

It is a summary of load carrying testing of DE Stubby.
Tom H
Stubby, a BDE
Treehugger, LEU

Offline Kiwi55

Re: Engine choice - Cabin Eagle
« Reply #7 on: March 10, 2017, 06:45:01 AM »
Thanks Tom that does help, but it also leave me a bit worried.
My Cabin Eagle is likely heavier and draggier than your DE.
It sounds like climb would be very marginal at max weight of 1050lb.

Offline Kiwi55

Re: Engine choice - Cabin Eagle
« Reply #8 on: March 10, 2017, 06:52:49 AM »
I have confirmed with Great Planes and Valley Engineering that if I installed a direct drive 2180 VW engine with force one hub (driving off front of engine), I could still install one of Valley Engineering reduction drives.
That at least gives me some flexibility if performance is not adequate with the direct drive.
I'm also still considering the AEROMOMENTUM AM13 option...

Offline Dave Stroud

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Re: Engine choice - Cabin Eagle
« Reply #9 on: March 10, 2017, 08:19:16 AM »
A few years back I had a chance to fly with Roger Enns in his Dragonfly. It had a very nice EA81 Subaru engine with no redrive but it did have a small turbo. What a simple system that worked very well. He'd taxi with the waste gate open ( no turbo action ) , take off and climb full power with the turbo, then back off the turbo for cruise. It worked perfectly. His prop must have been very carefully selected.
Dave Stroud
Ottawa, Canada

Offline libertyman777

Re: Engine choice - Cabin Eagle
« Reply #10 on: March 14, 2017, 07:15:44 AM »
Have you looked at this redrive?

I've wondered about using a redrive as well but for better short field performance.    But I'm guess the motor mount must be altered to account for the differences in thrust line. 

Offline Tom XL-7

Re: Engine choice - Cabin Eagle
« Reply #11 on: March 15, 2017, 07:06:14 AM »
I have now. It is probably as good as any other. Maybe better. These guys have little choice with their giant cowls. A normal prop would look silly and probably be of little use other than an engine cooling fan. I once built a scale Thomas Morse Scout that I powered with a .020 cox engine. Looked pretty stupid. Would have been better off with rubber power. 
   A man not far from where I grew up designed a little plane called the  Stewart Headwind. It was powered by a VW. He developed and patented a reduction called "the maximizer". Most current redrives are based on this patent. The point being this has been going on around 50 years and can work out.
 The props mentioned in your link were 7 and 8 footers. That's a bit much for clearance -even more so if you adjust for thrust line. 
 The concept of using the VW is simple, reliable, and inexpensive. 
When you get to that point ask yourself what you're gaining. It will come down to what prop you can throw. Then you can see if it is worth it. 
For those guys who just have to have a redrive, Don Stewart did develop one for the 1/2 VW. I can find no info on it.
 Tom XL-7

Offline Tom XL-7

Re: Engine choice - Cabin Eagle
« Reply #12 on: March 15, 2017, 08:00:53 AM »
I shouldn't bait you guys about the 1/2 VW with redrive.
I can find no info on it because it probably did not work out.
I think the power pulses are just too nasty to handle.

There is a builder who adjusted his thrust line lower for his half VW.
He wanted no doubt that when the throttle was opened up, the tendency would be to climb.
Imagine that.
Beats the alternative.
Tom XL-7

Offline cluttonfred

Re: Engine choice - Cabin Eagle
« Reply #13 on: March 16, 2017, 08:46:46 AM »
Have you considered contacting Scott Casler over at Hummel Engines?  He'll build the engine for you cheaper than Revmaster, in fact, cheaper than Great Plains or Aerovee will sell you a kit.  See

You might also consider the Davis Unified Igntion, basically GM HEI components in an integrated system, for your primary  (single?) or secondary ignition.  They custom tune the advance to your stated RPM needs and you only connect one wire to the unit for power and then the wires to the plugs, coil is inside.  It's a little wider and shorter than a Vertex magneto, so not terribly aerodynamic, but has a great reputation in automotive use.  See
Matthew Long, Editor
A site for builders, owners and fans of Eric Clutton's FRED
and other safe, simple, affordable homebuilt aircraft

Offline Kiwi55

Re: Engine choice - Cabin Eagle
« Reply #14 on: March 16, 2017, 10:56:20 AM »
Thanks I'll check them out as well.