RAH'er has forced landing

Matt's response gives me an thought. Has anyone ever tried a torque
converter by itself as a PSRU? Seems like it might solve a number of
problems, be relatively light, and not subject to wear. Just a thought -
I'm sure there would be lots of new problems.

--
Bob (Chief Pilot, White Knuckle Airways)

"Matt Whiting" wrote in message
...
wrote:
snip
And flywheels? That is one advantage of automatic transmissions, the TC
damps the torsional vibrations from the engine and prevents them from
reaching the transmission and drivetrain. Most standard shift vehicles
have spring hub clutch disks to help cushion the drive train.

Matt

Torque converters slip and convert HP into heat. Lossy.

There are torsional vibration dampers that are just high hysterisis
elastomers in a torque coupling that might help.

"Bob Chilcoat" wrote in message
...
Matt's response gives me an thought. Has anyone ever tried a torque
converter by itself as a PSRU? Seems like it might solve a number of
problems, be relatively light, and not subject to wear. Just a thought -
I'm sure there would be lots of new problems.

--
Bob (Chief Pilot, White Knuckle Airways)

"Matt Whiting" wrote in message
...
wrote:
snip
And flywheels? That is one advantage of automatic transmissions, the TC
damps the torsional vibrations from the engine and prevents them from
reaching the transmission and drivetrain. Most standard shift vehicles
have spring hub clutch disks to help cushion the drive train.

Matt

On Wed, 22 Dec 2004 12:31:10 -0500, "George A. Graham"
wrote:

Go ahead with your "I told you so's", just remember that there was not a
good alternative six years ago, and my junkyard gearbox has been good to
me.

What's important here George is that you made it down safely and
without damaging your airplane. Not everyone manages to do this, some
die in the attempt. I'm really impressed.

The secondary part is I'd sure like to know what failed in the
transmission. It's helpful information so that future experimenters
can know about it.

It would also be helpful to know what you did, if anything to modify
the transmission to become a psru.

Thanks George, you really got a nice present for Christmas.

Corky Scott

PS, You're famous ;-)

Bob Chilcoat wrote:
Matt's response gives me an thought. Has anyone ever tried a torque
converter by itself as a PSRU? Seems like it might solve a number of
problems, be relatively light, and not subject to wear. Just a thought -
I'm sure there would be lots of new problems.

I suspect that heat generation would be the killer for a typical auto
unit. Also, I don't know if the lock-up clutch would work at the torque
levels required in AC use. Probably other problems as well, but I'll
bet heat generation would be a biggie, especially if the lock-up clutch
couldn't be used. And if the lock-up could be used, you'd have no
reduction ratio, which means you'd no longer have have PSRU, just a PU! :-)


Matt

"Corky Scott" wrote in message ...
On Wed, 22 Dec 2004 03:11:51 GMT, "Blueskies"
wrote:

Doesn't the 'mazda' rotary mnimize this pulsation?

Not if the Powersport saga is to be believed. Their initial efforts
resulted in a LOT of psru failures.

See:
http://www.powersportaviation.com/Ho...on%20drive.htm

Ross Aero, on the other hand put together a planetary gear design and
seemed to suffer no torsional problems at all. They told me that some
engineer stopped in to tell them that he'd analized their reduction
unit and claimed that it would destructively vibrate at 300 rpm. Of
course the engine only sees that rpm during startup or shut down. The
rest of the time it's operating well above that.

The Ross Aero psru is what Tracy Crook initially used in his Mazda
powered RV-4. I gather he substantially modified it since then and
may now offer one of his own.

Corky Scott


I remember someone talking about a damper that was filled with steel shot or similar, but I cannot find a reference to
it now.

On Wed, 22 Dec 2004 22:39:59 GMT, "Blueskies"
wrote:


"Corky Scott" wrote in message ...
On Wed, 22 Dec 2004 03:11:51 GMT, "Blueskies"
wrote:

Doesn't the 'mazda' rotary mnimize this pulsation?

Not if the Powersport saga is to be believed. Their initial efforts
resulted in a LOT of psru failures.

See:
http://www.powersportaviation.com/Ho...on%20drive.htm

Ross Aero, on the other hand put together a planetary gear design and
seemed to suffer no torsional problems at all. They told me that some
engineer stopped in to tell them that he'd analized their reduction
unit and claimed that it would destructively vibrate at 300 rpm. Of
course the engine only sees that rpm during startup or shut down. The
rest of the time it's operating well above that.

The Ross Aero psru is what Tracy Crook initially used in his Mazda
powered RV-4. I gather he substantially modified it since then and
may now offer one of his own.

Corky Scott


I remember someone talking about a damper that was filled with steel shot or similar, but I cannot find a reference to
it now.


I can't recall the name, but they were used by Molt Taylor in his
pusher designs and were also used with the Honda Civic engine in some
BD-5s

Ed Sullivan

Not to be a putz, but if you had talked with the people in the old
days who started putting "car" engines in boats, they would have told
you that automotive manual transmissions were tried and generally found
wanting. Marine transmissions have spring or elastic couplings, similar
to those on auto clutches but bigger, and the gears are oversize.

A torsion damper of some type-either a spring or elastic coupling, a
quillshaft, or a belt or chain with a little stretch-is an absolute
necessity. There's a simple way of measuring the torsion flexion which
can be quickly used to troubleshoot the problems: on either side of the
coupling, a "tone wheel" or regularly spaced magnetic or optical 'mark'
is placed and a pickup-a LED/sensor or a simple solenoid coil (think
electric guitar or Hammond organ)is placed. The phase relationship
between the two signals is monitored and as the engine/load are cycled,
where the two signals "wobbles" is where the flexion is happening.
It's a simple test to rig up. OMC and Mercury have been doing this for
years. I know because I worked in a music store in Wisconsin and they
would buy a certain type of internally amplified guitar pickup for this
purpose.

On Wed, 22 Dec 2004 16:25:23 -0800, Ed Sullivan
wrote:

On Wed, 22 Dec 2004 22:39:59 GMT, "Blueskies"
wrote:


"Corky Scott" wrote in message ...
On Wed, 22 Dec 2004 03:11:51 GMT, "Blueskies"
wrote:

Doesn't the 'mazda' rotary mnimize this pulsation?

Not if the Powersport saga is to be believed. Their initial efforts
resulted in a LOT of psru failures.

See:
http://www.powersportaviation.com/Ho...on%20drive.htm

Ross Aero, on the other hand put together a planetary gear design and
seemed to suffer no torsional problems at all. They told me that some
engineer stopped in to tell them that he'd analized their reduction
unit and claimed that it would destructively vibrate at 300 rpm. Of
course the engine only sees that rpm during startup or shut down. The
rest of the time it's operating well above that.

The Ross Aero psru is what Tracy Crook initially used in his Mazda
powered RV-4. I gather he substantially modified it since then and
may now offer one of his own.

Corky Scott


I remember someone talking about a damper that was filled with steel shot or similar, but I cannot find a reference to
it now.


I can't recall the name, but they were used by Molt Taylor in his
pusher designs and were also used with the Honda Civic engine in some
BD-5s

Ed Sullivan
They were made by Dodge Power products, and I think they were called
FlexiDyne?

On Wed, 22 Dec 2004 15:45:03 -0500, Matt Whiting
wrote:

Bob Chilcoat wrote:
Matt's response gives me an thought. Has anyone ever tried a torque
converter by itself as a PSRU? Seems like it might solve a number of
problems, be relatively light, and not subject to wear. Just a thought -
I'm sure there would be lots of new problems.

I suspect that heat generation would be the killer for a typical auto
unit. Also, I don't know if the lock-up clutch would work at the torque
levels required in AC use. Probably other problems as well, but I'll
bet heat generation would be a biggie, especially if the lock-up clutch
couldn't be used. And if the lock-up could be used, you'd have no
reduction ratio, which means you'd no longer have have PSRU, just a PU! :-)


Just some clarification.

A fluid coupling is a lossy device - very lossy. A torque converter is
several orders of magnitude better, actually "converting" RPM and
Torque, very much similar to a gear train. Still lossy. You would NOT
want to use the lockup.

There WERE torque converters made with planetary gears in them as both
overdrives and underdrives. Not sure if anyone makes them any more.

Matt

wrote in message ...
On Wed, 22 Dec 2004 16:25:23 -0800, Ed Sullivan
wrote:

snip

I remember someone talking about a damper that was filled with steel shot or similar, but I cannot find a reference
to
it now.


I can't recall the name, but they were used by Molt Taylor in his
pusher designs and were also used with the Honda Civic engine in some
BD-5s

Ed Sullivan
They were made by Dodge Power products, and I think they were called
FlexiDyne?


BINGO---
http://www.dodge-pt.com/products/pt_...flexidyne.html