funny

On Wed, 08 Oct 2003 02:25:55 GMT, Peter Dohm
wrote:

Thanks, Corky,

I had wondered what became of the Geschwender reduction drives after Mr. G's
passing, and couldn't quite believe that a fully engineered and marketable
product would have been bandoned. For some reason, a Google search with the
argument fred + geschwender + psru gave Alternate Air Power, which now has a
web site. It is well out of my price range for the moment; but is actually
a real bargain when you consider the way it is built, and that it is made to
swing a constant speed prop.

Peter

Peter, the Geschwender unit was originally built for high output Ford
V-8's, power in the 450 hp range.

I actually had an opportunity to speak with Fred Geschwender and he
talked me out of using his PSRU because it was massive and overbuilt
for something like the Ford V-6, or anything that small.

I see from that website you mentioned that they now make something
that fits the smaller engines. They don't mention a price for it
though...

I was planning to use a hy-vo type reduction unit but came by a second
hand (unused) NW Aero 2 to 1 reduction ratio unit for less than half
price. That's what's on the no. 2 engine that's bolted into the
engine mount as a mockup right now.

Corky Scott

Corky Scott wrote:

On Wed, 08 Oct 2003 02:25:55 GMT, Peter Dohm
wrote:

Thanks, Corky,

I had wondered what became of the Geschwender reduction drives after Mr. G's
passing, and couldn't quite believe that a fully engineered and marketable
product would have been bandoned. For some reason, a Google search with the
argument fred + geschwender + psru gave Alternate Air Power, which now has a
web site. It is well out of my price range for the moment; but is actually
a real bargain when you consider the way it is built, and that it is made to
swing a constant speed prop.

Peter

Peter, the Geschwender unit was originally built for high output Ford
V-8's, power in the 450 hp range.

I actually had an opportunity to speak with Fred Geschwender and he
talked me out of using his PSRU because it was massive and overbuilt
for something like the Ford V-6, or anything that small.

I see from that website you mentioned that they now make something
that fits the smaller engines. They don't mention a price for it
though...

I was planning to use a hy-vo type reduction unit but came by a second
hand (unused) NW Aero 2 to 1 reduction ratio unit for less than half
price. That's what's on the no. 2 engine that's bolted into the
engine mount as a mockup right now.

Corky Scott

Corky,

I don't know whether a lot of smaller manufacturers have frequently added
a web presence, or your earlier post just gave me a key to better search
arguments.

You are certainly right about Fred Geschwender's original design goals,
which appear to be shared by EPI, Inc. If you need a tremendous amount
of power on take-off, a controllable prop, and possibly a reduced power
cruise; then the hy-vo units look like a real bargain. In the simplest
form, a 300 horsepower big-block truck engine with a PSRU and constant
speed propeller should be well under 30K; which looks pretty respectable
against a 260HP Lycoming or Continental also new and equipped with a
constant speed propeller. Add the nacelle shape requirement for a good
P51 replica and the market, aside from Ag planes, is understandable.

It happens that I in your end of the marketplace and I am gradually
beginning to accept the idea that a PSRU which cannot accept a constant
speed prop is not necessarily a bad thing; and is probably as reliable.

I am a little curious about the specifics of how the 2:1 reduction ratios
are acheived on both the belt and hy-vo chain drives, as I learned a
number of years ago that evenly divisible ratios (such as 2.0:1, 1.50:1,
3.0:1, etc.) should be avoided in spur gear type reduction drives as
they will wear unevenly and require more frequent overhaul. The problem
occurs when the same gear teeth consistently transmit the power or
compression strokes of the engine, and can be mitigated by slightly
hanging the ratios; usually by one tooth on either the drive gear or
the driven gear. However, since the drive gear is fixed to the crank
shaft, the uneven wear problem can not be eliminated in a spur geared
system.

In the case of a belt or hy-vo chain system, it should be possible to
mitigate the wear problem to a similar degree if the number of teeth
on the chain is not divisible by those of either of the two pulleys;
although the crank shaft pulley is obviously the more important of the
two.

I couldn't find much on the Northwest-aero web site regarding the
"innards" of their PSRU, so I am curious.

Peter Dohm

"Peter Dohm" wrote in message
...


I couldn't find much on the Northwest-aero web site regarding the
"innards" of their PSRU, so I am curious.

Peter Dohm

It is a toothed belt system.
--
Jim in NC

Morgans wrote:

"Peter Dohm" wrote in message
...


I couldn't find much on the Northwest-aero web site regarding the
"innards" of their PSRU, so I am curious.

Peter Dohm

It is a toothed belt system.
--
Jim in NC

Thanks, Jim,

Hopefully, the teeth on the belt are not divisible by the teeth on the
drive pulley; so that the belt will wear evenly. It the sort of feature
that I would expect every manufacturer to mention in their promotional
material, so I am given to wonder when it appears that none of them do.

Peter Dohm

A Hy-Vo chain drive should ideally use an even number of links in the chain.
And also have one even count sprocket and one odd count sprocket. So a 2 to
1 is possible say with a 50/25 sprocket combination. A properly designed
Hy-Vo drive will have a B10 chain life measered in 10's of thousands of
hours. An improperly designed one can have a chain live measured in 10's of
hours. For example a 2" wide 3/8 pitch chain in one case will be a 17 hour
B10. Replace the 2" with 3" wide and the life is 26,000 hours in the exact
same situation. In the first case the chain will break due to link fatigue
before it gets the chance to wear.

Hy-Vo chain is also very tollerant of center to center distance in
comparison to cog belts.

EPI has the best info regarding Hy-Vo chain use in a PSRU that I've seen.

Kenny Bauman



"Peter Dohm" wrote in message
...
Corky Scott wrote:

On Wed, 08 Oct 2003 02:25:55 GMT, Peter Dohm
wrote:

Thanks, Corky,

I had wondered what became of the Geschwender reduction drives after
Mr. G's
passing, and couldn't quite believe that a fully engineered and
marketable
product would have been bandoned. For some reason, a Google search
with the
argument fred + geschwender + psru gave Alternate Air Power, which now
has a
web site. It is well out of my price range for the moment; but is
actually
a real bargain when you consider the way it is built, and that it is
made to
swing a constant speed prop.

Peter

Peter, the Geschwender unit was originally built for high output Ford
V-8's, power in the 450 hp range.

I actually had an opportunity to speak with Fred Geschwender and he
talked me out of using his PSRU because it was massive and overbuilt
for something like the Ford V-6, or anything that small.

I see from that website you mentioned that they now make something
that fits the smaller engines. They don't mention a price for it
though...

I was planning to use a hy-vo type reduction unit but came by a second
hand (unused) NW Aero 2 to 1 reduction ratio unit for less than half
price. That's what's on the no. 2 engine that's bolted into the
engine mount as a mockup right now.

Corky Scott

Corky,

I don't know whether a lot of smaller manufacturers have frequently added
a web presence, or your earlier post just gave me a key to better search
arguments.

You are certainly right about Fred Geschwender's original design goals,
which appear to be shared by EPI, Inc. If you need a tremendous amount
of power on take-off, a controllable prop, and possibly a reduced power
cruise; then the hy-vo units look like a real bargain. In the simplest
form, a 300 horsepower big-block truck engine with a PSRU and constant
speed propeller should be well under 30K; which looks pretty respectable
against a 260HP Lycoming or Continental also new and equipped with a
constant speed propeller. Add the nacelle shape requirement for a good
P51 replica and the market, aside from Ag planes, is understandable.

It happens that I in your end of the marketplace and I am gradually
beginning to accept the idea that a PSRU which cannot accept a constant
speed prop is not necessarily a bad thing; and is probably as reliable.

I am a little curious about the specifics of how the 2:1 reduction ratios
are acheived on both the belt and hy-vo chain drives, as I learned a
number of years ago that evenly divisible ratios (such as 2.0:1, 1.50:1,
3.0:1, etc.) should be avoided in spur gear type reduction drives as
they will wear unevenly and require more frequent overhaul. The problem
occurs when the same gear teeth consistently transmit the power or
compression strokes of the engine, and can be mitigated by slightly
hanging the ratios; usually by one tooth on either the drive gear or
the driven gear. However, since the drive gear is fixed to the crank
shaft, the uneven wear problem can not be eliminated in a spur geared
system.

In the case of a belt or hy-vo chain system, it should be possible to
mitigate the wear problem to a similar degree if the number of teeth
on the chain is not divisible by those of either of the two pulleys;
although the crank shaft pulley is obviously the more important of the
two.

I couldn't find much on the Northwest-aero web site regarding the
"innards" of their PSRU, so I am curious.

Peter Dohm

Bob,
I was sittin on the fence about your thoughts on the egine debate
subject. What you wrote above makes sense and I now have an idea as to
the thougth process in your arguments.

all the best
Sean Trost

Barnyard BOb -- wrote:

GEEEEEEE You are getting old if that is the only rise out of you for saying you
sounded like Paul Lamar...I would have thought the ground would have shook.

BFG


Few will believe this....
But, my blood pressure stays flat through all this RAH stuff UNTIL....
somebody says something truly funny. Yep. I can be caught rolling
on the floor at 3, 4, or 5 AM.


I also believe the Mazda would be a good choice but not for the inexperienced.


The crux of the matter is there are few as gifted at Tracy Crooks.


My whole point is that auto engines can be successfully adapted for aircraft
use, not just the Mazda, IF you know what you are doing.


Super humongous... "IF".
And where is the financial responsibility coming from?
Your personal assets ?

No insurance company wants to write a low time pilot, with no time
in type, playing test pilot with a one of a kind homebrew engine.
They'd have to be as nuts as the builder/pilot/engine combo.


I don't believe it
will be significantly cheaper and that is proven by the cost of the many
conversion engines on the market.


Those that believe otherwise are delusional and should not even
be allowed near a wrench, torch or hammer. However, this is where
most of the boos and hisses come from. Yes, I'm speaking in
generalities, but it is GENERALLY TRUE.


It should also not be done by anyone that
doesn't have the knowledge to do the maintenance on the engine, anytime and
anywhere.


Bob Reed


FIRST...
You have to get past the engineering obstacles before you can
even think about a maintenance program. For my money,
the R & D never ends and therefore....
passengers should not be put at risk in this kind of experimenting.
This is an area of risk that insurance companies are loathe to write.

If I'm wrong, show me where.


Barnyard BOb --



Barnyard BOb --

On Thu, 09 Oct 2003 23:37:37 GMT, Peter Dohm
wrote:


I am a little curious about the specifics of how the 2:1 reduction ratios
are acheived on both the belt and hy-vo chain drives, as I learned a
number of years ago that evenly divisible ratios (such as 2.0:1, 1.50:1,
3.0:1, etc.) should be avoided in spur gear type reduction drives as
they will wear unevenly and require more frequent overhaul. The problem
occurs when the same gear teeth consistently transmit the power or
compression strokes of the engine, and can be mitigated by slightly
hanging the ratios; usually by one tooth on either the drive gear or
the driven gear. However, since the drive gear is fixed to the crank
shaft, the uneven wear problem can not be eliminated in a spur geared
system.

In the case of a belt or hy-vo chain system, it should be possible to
mitigate the wear problem to a similar degree if the number of teeth
on the chain is not divisible by those of either of the two pulleys;
although the crank shaft pulley is obviously the more important of the
two.

I couldn't find much on the Northwest-aero web site regarding the
"innards" of their PSRU, so I am curious.

Peter Dohm

Peter, perhaps Bruce Frank can tell you more about the cog belt
systems, I can only give you an overview. Bruce issues a newsletter
on the subject and has written about a guy who managed to accumulate
2,000 hour on his engine/psru (Ford 3.8L V-6 with 2 to 1 ratio cog
belt psru). At that point, he tore down the engine and also inspected
the psru. He replaced the belt, but did not actually discern much
wear on it. His impression was that it could have run much longer.

The 2 to 1 ratio drives don't seem to have any abnormal wear pattern
that has been reported.

The problem you describe may be specific to metal to metal gears
meshing.

Corky Scott

In article , sean trost
writes:


Bob,
I was sittin on the fence about your thoughts on the egine debate
subject. What you wrote above makes sense and I now have an idea as to
the thougth process in your arguments.

all the best
Sean Trost



BOb is like the old military sargents who used to state "When I say Jump, you
jump and only ask how high on the way up but you NEVER ask why". Sometimes you
have to get down and dirty with him to get the why, but in most cases, it is
pretty valid reasoning.


Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

Bart D. Hull wrote:

Bob,

I'm just not happy with the old injection systems, ignition systems
and starting issues with the Lycs. If I throw all those away, I just
have a old air-cooled long block anyways. A big question I see is what
IF they do away with 100LL and replace it with 82UL? What then for
those old Lyc's and Conts'? I know its a vague threat by those
environmentalist types but what if they manage it?

I do understand your comments about tried and true but at one time
they were "cutting edge" as well, right? In your 50 years of flying
you must have had a
time that you thought, "Man the old XXXXX engine (or plane) was a
piece of ****
I'm glad I'm flying a XXXXXXX now."

I think its time to bring airplane engines and their systems up to
more modern and reliable levels. I don't mean more complicated, but
things have come a long way since air cooled, low compression, twin
valve per cylinder, pushrod engine.

Yes, it's more work than just installing a Lyc, it will require more
effort to work out the bugs (as on any new engine install.) and I'll
need to provide the technical support myself. (better than trusting my
life to something I'm not intimately familiar with.)

Too many think of a auto-conversion as a "cheap" engine, I don't see
it this way
if you plan to have a successful conversion. No pinto distributors,
old Holley
two barrels, used fuel tank pumps, standard EFI boxes on my engine.
Even a
turbo for altitude equalization not a "Rice Boy" HP until it blows
installation.

The Honda-Lyc will be very similar to a auto-conversion as is the
Bombardier V-6. Both have serious investments to bring them up to
date. I am watching them carefully to follow the millions of bucks
they are spending to learn how to build a reliable new generation
engine package that pilots will trust.

Would you put a Honda-Lyc or a Bombardier V-6 (200 or 300 HP) on your
2nd RV-3?

And yes I take "junior" as a complement as I'm quite the youngster at
35 years of age. As far as youthful foolishness, we all do it some
time in our life and
yet most of us make it to a ripe old age.


--
Bart D. Hull

Tempe, Arizona

Check http://www.inficad.com/~bdhull/engine.html
for my Subaru Engine Conversion
Check http://www.inficad.com/~bdhull/fuselage.html
for Tango II I'm building.

Peter Dohm wrote:

I am a little curious about the specifics of how the 2:1 reduction ratios
are acheived on both the belt and hy-vo chain drives, as I learned a
number of years ago that evenly divisible ratios (such as 2.0:1, 1.50:1,
3.0:1, etc.) should be avoided in spur gear type reduction drives as
they will wear unevenly and require more frequent overhaul. The problem
occurs when the same gear teeth consistently transmit the power or
compression strokes of the engine, and can be mitigated by slightly
hanging the ratios; usually by one tooth on either the drive gear or
the driven gear. However, since the drive gear is fixed to the crank
shaft, the uneven wear problem can not be eliminated in a spur geared
system.

Peter Dohm

Actually it has been found that exactly 2:1 ratio with a cog belt PSRU
runs trouble free whereas one tooth above or below that ratio caused a
very noisy unit. (Dave Blanton's original development work)
--
Bruce A. Frank, Editor "Ford 3.8/4.2L Engine and V-6 STOL
Homebuilt Aircraft Newsletter"
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