what engines are making successful aero engine conversions?

I think the topic (40hp engine) is of sufficient interest
internationally to justify some form of permanent address on the
internet. The problem is only going to become worse.

-R.S.Hoover

Stealth Pilot wrote:


hoover you are proof positive that old dogs can learn new tricks!
I note the use of the word Holden :-) and punch that upturned thumb to
the sky thinking yesss hoover you are a champion :-) :-)


Personally, I want to see a flying commie-knocker ;')

Charles

On May 14, 2:34*pm, wrote:
Dear Stealth (and the Group)

We may be looking it this the wrong 'way 'round.

There are plenty of engines which offer excellent power-to-weight
ratios. *Unfortunately, they do so at rpm's which make them
impractical for slinging a prop UNLESS a PSRU is used.

A good case-in-point is the Rotax. *The Rotax engine is only 1300cc
but it is designed to operate near 6000 rpm. *What makes the engine
successful is the PSRU between the engine and the prop.

There are two obvious conclusions we can draw from this. *The first is
that the engines themselves, despite any practical combination of cam
& cooling, are simply too small to be used with the propeller mounted
directed to the crankshaft. *(This leads to another series of
questions worthy of discussion but which I will leave untouched at
this time.)

The second point is that the PSRU, which does NOT enjoy the same TBO
as the engine itself, has been designed specifically for this
application, taking advantage of the engine's torque & power curves,
and including mechanical features that make it suitable for the
mounting of a propeller; mounting the engine to an airframe and so
forth.

It may then be argued that we are wasting our time by focusing on the
ENGINE; that we should be devoting our energies to a suitable PSRU
that may be attached to a WIDE VARIETY of engines.

Having devoted most of my attention to the VW engine, I have little to
offer the Group should the discussion turn to PSRU's but it would seem
that the hand-maiden of these light-weight, powerful engines MUST be
an automotive TRANSMISSION having similar features of light-weight and
power-handling capacity. *Here again, I lack the background and
experience to do more than mutter; there are aspects of PSRU's,
transmissions and torque converters about which I know nothing at
all... other than the fact they must exist (since the engines exist).

At the very least, I know the GEARS must exist.

Were I in Western Australia, rather than curse the darkness (and wish
for a Corvair to suddenly appear on my doorstep) I think I would light
a single candle by diving into whatever came my way in the form of
light-weight engines and trannies.

I suppose there has to be a clutch in there somewhere, so that means
I'm probably looking at a flywheel as well... fate stacking the weight
against my urge to fly. *But perhaps some of those powerful, light-
weight engines ARE large enough to be able to drive a prop directly,
even if I had to find someone to grind me a new cam.
Re. PSRU's

There is a gear reduction unit that handles massive torque and power
the size of a a one-pound coffee can - it's the planetary gearset from
an automatic transmission. I have two in my Jeep Grand Cherokee
'airport car' transmission that have lasted 300,000 miles - so far.
These things are built to very tight tolerances and are VERY tough.

If you want still tougher, speed shops sell replacement planetaries
that can handle 1500HP or more. Ask one to handle only 100HP and
they should last forever. You can specify just about any reduction
ratio you want.

All you have to do is machine a nose case from billet aluminum to hold
the planetary gearset and the thrust bearing.

On May 16, 4:13 pm, bildan wrote:
Re. PSRU's

There is a gear reduction unit that handles massive torque and power
the size of a a one-pound coffee can - it's the planetary gearset from
an automatic transmission. I have two in my Jeep Grand Cherokee
'airport car' transmission that have lasted 300,000 miles - so far.
These things are built to very tight tolerances and are VERY tough.

If you want still tougher, speed shops sell replacement planetaries
that can handle 1500HP or more. Ask one to handle only 100HP and
they should last forever. You can specify just about any reduction
ratio you want.

All you have to do is machine a nose case from billet aluminum to hold
the planetary gearset and the thrust bearing.

I wish it was so simple. Without a flywheel and/or torque converter
to damp the engine's power pulses, the engine's desire to run in a
vibratory fashion will conflict with the prop's desire to run
smoothly, and at some resonant RPM the gears can die. They need almost
zero lash, or some heavy flywheel on the engine, or the damping of a
torque converter.

Dan

On May 16, 4:34*pm, wrote:
On May 16, 4:13 pm, bildan wrote:

Re. PSRU's

There is a gear reduction unit that handles massive torque and power
the size of a a one-pound coffee can - it's the planetary gearset from
an automatic transmission. *I have two in my Jeep Grand Cherokee
'airport car' transmission that have lasted 300,000 miles - so far.
These things are built to very tight tolerances and are VERY tough.

If you want still tougher, speed shops sell replacement planetaries
that can handle 1500HP or more. *Ask *one to handle only 100HP and
they should last forever. *You can specify just about any reduction
ratio you want.

All you have to do is machine a nose case from billet aluminum to hold
the planetary gearset and the thrust bearing.

* *I wish it was so simple. Without a flywheel and/or torque converter
to damp the engine's power pulses, the engine's desire to run in a
vibratory fashion will conflict with the prop's desire to run
smoothly, and at some resonant RPM the gears can die. They need almost
zero lash, or some heavy flywheel on the engine, or the damping of a
torque converter.

Dan

I didn't suggest that no flywheel would be necessary but it also
depends on the number of cylinders. A 4-cyl will need a heavy one but
an 8 cylinder could do with less.

bildan wrote:
....
Re. PSRU's
There is a gear reduction unit that handles massive torque and power
the size of a a one-pound coffee can - it's the planetary gearset from
an automatic transmission. ...
*
*
... Without a flywheel and/or torque converter
to damp the engine's power pulses, the engine's desire to run in a
vibratory fashion will conflict with the prop's desire to run
smoothly, and at some resonant RPM the gears can die....
Dan

... it also depends on the number of cylinders.
A 4-cyl will need a heavy one but an 8 cylinder could do with less.

Car engines often feature a crank damper on the front end.
This stops the angular oscillations that lead to crack ups.
Manual transmissions feature sprung drive on the live clutch plate.
This can serve a similar purpose. Besides the fluid flywheel there is
also the rubber spider drive to the half shaft, on some sports coupes.

As an odd-ball thought, wouldn't it be nice if two tubes sized to fit a
fabric reinforced hose pipe between them, and epoxied to both tubes
were arranged with a gap in the inner steel tube, then a gap in the
outer tube alternately - arranged to provide angular give in 'series'
for a soft, vibration absorbing drive shaft....

Brian W

wrote:

On May 16, 4:13 pm, bildan wrote:
Re. PSRU's

There is a gear reduction unit that handles massive torque and power
the size of a a one-pound coffee can - it's the planetary gearset from
an automatic transmission. I have two in my Jeep Grand Cherokee
'airport car' transmission that have lasted 300,000 miles - so far.
These things are built to very tight tolerances and are VERY tough.

If you want still tougher, speed shops sell replacement planetaries
that can handle 1500HP or more. Ask one to handle only 100HP and
they should last forever. You can specify just about any reduction
ratio you want.

All you have to do is machine a nose case from billet aluminum to hold
the planetary gearset and the thrust bearing.

I wish it was so simple. Without a flywheel and/or torque converter
to damp the engine's power pulses, the engine's desire to run in a
vibratory fashion will conflict with the prop's desire to run
smoothly, and at some resonant RPM the gears can die. They need almost
zero lash, or some heavy flywheel on the engine, or the damping of a
torque converter.

Dan

I'm not sure that we can handle someone who knows what he is talking about, Dan.
Isn't this group about speculation and WAGs.

Seriously, Tracy Crook and others have done a lot of work on the planetary gear
redrive in conjunction with the Wankel rotary, which BTW is a much better
solution to the overall search for the optimal aircraft engine. Their
conclusions are similar to the ones you pointed to.

On May 18, 7:44*am, routund wrote:
wrote:
On May 16, 4:13 pm, bildan wrote:
Re. PSRU's

There is a gear reduction unit that handles massive torque and power
the size of a a one-pound coffee can - it's the planetary gearset from
an automatic transmission. *I have two in my Jeep Grand Cherokee
'airport car' transmission that have lasted 300,000 miles - so far.
These things are built to very tight tolerances and are VERY tough.

If you want still tougher, speed shops sell replacement planetaries
that can handle 1500HP or more. *Ask *one to handle only 100HP and
they should last forever. *You can specify just about any reduction
ratio you want.

All you have to do is machine a nose case from billet aluminum to hold
the planetary gearset and the thrust bearing.

* I wish it was so simple. Without a flywheel and/or torque converter
to damp the engine's power pulses, the engine's desire to run in a
vibratory fashion will conflict with the prop's desire to run
smoothly, and at some resonant RPM the gears can die. They need almost
zero lash, or some heavy flywheel on the engine, or the damping of a
torque converter.

Dan

I'm not sure that we can handle someone who knows what he is talking about, Dan.
Isn't this group about speculation and WAGs.

Seriously, Tracy Crook and others have done a lot of work on the planetary gear
redrive in conjunction with the Wankel rotary, which BTW is a much better
solution to the overall search for the optimal aircraft engine. *Their
conclusions are similar to the ones you pointed to.

I hear rumors of a Japanese motorcycle maker that will introduce a
500cc inline 4 with direct injection. If it lives up to its Japanese
reputation, it will produce about 50 very reliable HP.

Take 5 of these 4-cyl blocks and arrange them around a common case and
crank to make a 20 cylinder, 250HP liquid cooled radial. De-rate it
to 150HP for reliability. Since it uses direct injection, the
plumbing would be air in and exhaust out. Fuel lines would be 3mm
stainless tubing from a common rail to the cylinder heads.

20 cylinders would make the engine smooth enough that the crank itself
would be plenty of flywheel. (Ever see a flywheel on a geared
radial?) A planetary in the nose case would get the prop RPM down
below 2000 RPM.

BTW, I don't think casting has any place in prototyping. Design the
parts with SolidWorks, email the file to a CNC shop who will mill them
from billet and ship the parts in a week. Machined billet parts are
FAR better than castings - and cheaper.

On May 18, 6:44*am, routund wrote:
wrote:
On May 16, 4:13 pm, bildan wrote:
Re. PSRU's

There is a gear reduction unit that handles massive torque and power
the size of a a one-pound coffee can - it's the planetary gearset from
an automatic transmission. *I have two in my Jeep Grand Cherokee
'airport car' transmission that have lasted 300,000 miles - so far.
These things are built to very tight tolerances and are VERY tough.

If you want still tougher, speed shops sell replacement planetaries
that can handle 1500HP or more. *Ask *one to handle only 100HP and
they should last forever. *You can specify just about any reduction
ratio you want.

All you have to do is machine a nose case from billet aluminum to hold
the planetary gearset and the thrust bearing.

* I wish it was so simple. Without a flywheel and/or torque converter
to damp the engine's power pulses, the engine's desire to run in a
vibratory fashion will conflict with the prop's desire to run


Seriously, Tracy Crook and others have done a lot of work on the planetary gear
redrive in conjunction with the Wankel rotary, which BTW is a much better
solution to the overall search for the optimal aircraft engine. *Their
conclusions are similar to the ones you pointed to.

One of Tracy's non-intuitive conclusions was that zero lash was NOT
necessary, and that increasing lash reduced the natural frequency of
the system. Increase the lash enough, and the "rattle" is below idle
speed. Tracy DOES use a rubber damping element on the drive side of
his units.
http://www.rotaryaviation.com/psru_development.htm

================================================== =

Tracy's units are based on the Ford C-6 truck transmission, and are
too heavy for a 40 - 60 HP engine. How about something lighter? I
propose we take a look at the Toyota A131L, which was in production
FOREVER
Applications:
* 1984-2002 Toyota Corolla (1.6L 4A-FE / 3 spd.) (includes FX)
* 1985–1988 Chevrolet Nova
* 1990-1992 geo prizm
Another possible choice would be the A40
Applications:
* Carina 1600 rwd 08/75-04/84
* Carina 1800 rwd 04/81-04/84
* Celica 2000 rwd 01/78-07/82
* Corolla 1300 03/80-09/83
* Corona liftback 04/79-03/81
* Cressida 12/77-06/81
* Cressida 2000 05/81-09/82
* Crown 2600 05/77-03/80
* Starlet 1300 02/82-02/85
or the 245E
Applications:* 1993-2007 Corolla 1.8L 7A-FE

On Wed, 13 May 2009 06:40:13 GMT, Stealth Pilot
wrote:


I'm in Western Australia. locally our supplies of VW engines seem to
have dried up. Even BMW motor cycle engines seem to have dried up.
what other currently available engines have been successfully used in
aircraft?

the engine problem seems to provide the most unsolvable dilema when
attempting to build a small aircraft. I'd hate to think that the
prospect of engine conversions was passing.

Stealth Pilot

Why do we always assume we have to reinvent the wheel? If you need 40
hp, here it is. Even altitude compensating EFI available soon.
Designed for max continuous power. Rig a PSRU with a poly-v belt for
more efficient prop speed/length.

40 not enough, stack 2 end to end. Have a steel crank made if the iron
makes you nervous.

Not every small gas engine is a Briggs. I've run 100s of these Kohlers
for 40 years. Some 2000 hours in a year. Almost all the 30 and 40 year
old garden tractors have Kohlers or Tecumsehs. Not many Briggs.

Model Command PRO CH1000
Max Power @3600 RPM hp (kW) 40 (29.8)
Displacement cu in (cc) 61 (999)
Bore in (mm) 3.5 (90)
Stroke in (mm) 3.1 (78.5)
Peak Torque @ Maximum lbs ft (Nm) 61.5 (83.4)
Compression Ratio 8.8:1
Dry Weight lbs (kg) 132 (59)
Oil Capacity U.S. quarts (L) 2.9 (2.75)
Lubrication Full pressure w/full-flow filter
Dimensions L x W x H in 15.3 x 19.0 x 27.5