Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

"Sunworshipper" wrote in message
...
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

The liability would scare me!

It would take me about 2 seconds to decline doing anything design
related to an airplane. You could do a great job and then the guy could
fly drunk and crash and you could loose everything you've got just
because you are in litigious (sp?) America.

Pete Stanaitis
---------------

Sunworshipper wrote:

Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

On Jul 8, 5:29*pm, Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. *I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

They should have used a corvair engine- no speed reduction needed
(apparently)!

http://www.hainesengineering.com/rha...vair.htm#hubon


Dave

On Jul 8, 5:29*pm, Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. *I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

Looks like a blower setup...

http://www.raven-rotor.com/html/redrive.html

Dave

On 07/08/2010 03:30 PM, spaco wrote:
(top posting fixed)

Sunworshipper wrote:

Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but

snip

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

It would take me about 2 seconds to decline doing anything design
related to an airplane. You could do a great job and then the guy could
fly drunk and crash and you could loose everything you've got just
because you are in litigious (sp?) America.

Yup. Back away slowly until he can't see you, then run like hell.

Not just because it's for a plane -- if I knew the guy already I might
make a part or two. It's the fact that a couple of grooves in a pulley
morphed into a design/engineering task -- that means that the guy is
clueless, which means that you can't trust him to build the rest of the
plane right.

(my spell checker thinks "litigious" is just fine).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

My friend Chuck and I built a (roughly) 3/4 scale SE-5A (many years ago)
that had a 3 cylinder Geo on it.

Chuck adapted a Rotax "B" box for it. That involved making a mount plate
that fit the motor on one side and bossed in the box on the other.
I recall a spacer on the box side to get the gears to mate up right,
but no details now.


But he also turned down the flywheel to reduce weight.
That's a common task on VWs and Subarus and can really help.
But the Geo flywheel weight is directly proportional to engine life.
It HAS to have the whole flywheel or the crank shaft breaks in 10 to 12 hours.
It's a resonance issue related to 3 hole motors.
And, yes, it broke in flight! Of course.

On a couple of other (2 and 4 cylinder) projects we used belts.

Don't bother with multiple V belts - it's not possible to get several
close enough to the same size to work reliably. And when one goes, the
rest are immediately overloaded and let go as well.

We never found a single V belt arrangement that worked well or was at all
reliable. This on motors in the 50 to 80 hp range.

The best belt solution was the Gates PolyChain set up.

Home made wheels of aluminum worked ok, but hard anodizing is recommended.
Chuck made a cutter for that odd rounded tooth pattern, and with a bit of
practice, made some serviceable wheels.

One of the problem areas is the bottom (engine side) drive pulley.
It needs to be as small as possible to keep the driven wheel from being too
large, but small wheels cause higher tooth loads and wear rapidly.

Harmonic resonance issues require staying away from even numbered ratios.
IE: 2:1 is horrible for resonance. 2.58:1 is much better!
(Guitar players can explain this real well)

Hard learned lesson - don't loose your count on the gear cutter,
and never EVER try to back up!


I've seen the Raven belt setup and was impressed.
http://www.raven-rotor.com/html/redrive.html

Might want to explore the planetary gear boxes as the parts are
smaller and generally available off the shelf.
http://www.rotorcraft.com/ads/nhc.html
http://www.wingsforum.com/viewtopic.php?p=22031
http://www.rotaryaviation.com/Aviation_Prod.htm

Excess weight on the nose of a very light airplane is a real killer.
The airplane MUST balance properly to be at all controllable.
Ballast on the tail may be necessary.
Call it Static Stability Augmentation if anybody objects to "ballast".


But my heart-felt bottom-line advice would be to politely RUN (not walk)
away
from this kind of project.

Beyond the research and development (R&D = ReDo)
is the legal liability in the event of a catastrophic failure.

As we have found out over the years, it's a no win situation...

Build your own if you want.

But be careful of the ramifications of building for others...


Respects,

Richard Lamb



Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I tought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.


--

Richard Lamb

Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

Is the engine using a flywheel or is it using the prop. for a flywheel?
A belt would take up the
slack from a "driven and drive" vibration situation. A gear reducer has
to stand up to that
vibration

Bill K7NOM.

On Thu, 08 Jul 2010 18:42:13 -0500, cavelamb
wrote:

My friend Chuck and I built a (roughly) 3/4 scale SE-5A (many years ago)
that had a 3 cylinder Geo on it.

Chuck adapted a Rotax "B" box for it. That involved making a mount plate
that fit the motor on one side and bossed in the box on the other.
I recall a spacer on the box side to get the gears to mate up right,
but no details now.


But he also turned down the flywheel to reduce weight.
That's a common task on VWs and Subarus and can really help.
But the Geo flywheel weight is directly proportional to engine life.
It HAS to have the whole flywheel or the crank shaft breaks in 10 to 12 hours.
It's a resonance issue related to 3 hole motors.
And, yes, it broke in flight! Of course.

On a couple of other (2 and 4 cylinder) projects we used belts.

Don't bother with multiple V belts - it's not possible to get several
close enough to the same size to work reliably. And when one goes, the
rest are immediately overloaded and let go as well.

We never found a single V belt arrangement that worked well or was at all
reliable. This on motors in the 50 to 80 hp range.

The best belt solution was the Gates PolyChain set up.

Home made wheels of aluminum worked ok, but hard anodizing is recommended.
Chuck made a cutter for that odd rounded tooth pattern, and with a bit of
practice, made some serviceable wheels.

One of the problem areas is the bottom (engine side) drive pulley.
It needs to be as small as possible to keep the driven wheel from being too
large, but small wheels cause higher tooth loads and wear rapidly.

Harmonic resonance issues require staying away from even numbered ratios.
IE: 2:1 is horrible for resonance. 2.58:1 is much better!
(Guitar players can explain this real well)

Hard learned lesson - don't loose your count on the gear cutter,
and never EVER try to back up!


I've seen the Raven belt setup and was impressed.
http://www.raven-rotor.com/html/redrive.html

Might want to explore the planetary gear boxes as the parts are
smaller and generally available off the shelf.
http://www.rotorcraft.com/ads/nhc.html
http://www.wingsforum.com/viewtopic.php?p=22031
http://www.rotaryaviation.com/Aviation_Prod.htm

Excess weight on the nose of a very light airplane is a real killer.
The airplane MUST balance properly to be at all controllable.
Ballast on the tail may be necessary.
Call it Static Stability Augmentation if anybody objects to "ballast".


But my heart-felt bottom-line advice would be to politely RUN (not walk)
away
from this kind of project.

Beyond the research and development (R&D = ReDo)
is the legal liability in the event of a catastrophic failure.

As we have found out over the years, it's a no win situation...

Build your own if you want.

But be careful of the ramifications of building for others...


Respects,

Richard Lamb




Hold the presses, we've got a great come back.

One of the first things I asked this guy was how big the back main
journal is. I have ground aircraft cranks in a past life time.

Oh well thanks

Sounds like very good advice all around.









Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I tought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

On Thu, 08 Jul 2010 16:29:39 -0500, Sunworshipper
wrote:

Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.


Wasn't there someone in this N.G. building an air boat, a while back,
with exactly the same problems? Apparently successfully accomplished.

Cheers,

John D. Slocomb
(jdslocombatgmail)

On 7/8/2010 5:29 PM, Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane.

Ted Edwards put pictures of an aircraft speed reducer he fabricated
(with a Smithy)in the dropbox.

http://www.metalworking.com/dropbox/_2004_retired_files/Prop_speed_reducer.pdf

Kevin Gallimore

Tim Wescott fired this volley in news:-
:


Not just because it's for a plane -- if I knew the guy already I might
make a part or two. It's the fact that a couple of grooves in a pulley
morphed into a design/engineering task -- that means that the guy is
clueless, which means that you can't trust him to build the rest of the
plane right.

You don't have to trust him to build the plane; it's an experimental.
The _instant_ he puts a non-STC'd part on any aircraft, commercial or
otherwise, it becomes an experimental aircraft.

I, too, would turn down the task because the guy didn't have
specifications -- only hopes. But the liability risk is actually pretty
small. NTSC doesn't have jurisdiction over experimental craft, and
experimental pilots crack up all the time.

Of course, owners do all sorts of "custom" minor modifications to their
commercial craft: instruments, decorations, minor fittings like latches
and knobs. But the moment you modify the controls, the airframe, or the
powerplant (this pulley) you're off the chart, and on your own. And this
doesn't even seem to be a modification, but a build.

Mostly, I'd turn him down because he doesn't really know what he wants,
and not being an A&P mechanic myself, _I_ don't know what he wants,
either.

LLoyd (SEL pilot with about 1000 hours)

On Thu, 08 Jul 2010 21:23:29 -0400, axolotl
wrote:

On 7/8/2010 5:29 PM, Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane.

Ted Edwards put pictures of an aircraft speed reducer he fabricated
(with a Smithy)in the dropbox.

http://www.metalworking.com/dropbox/_2004_retired_files/Prop_speed_reducer.pdf

Kevin Gallimore

Great find, looks like they had the same problems I was thinking of.

SW

On Thu, 08 Jul 2010 16:29:39 -0500, Sunworshipper
wrote:

Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.
Recommend the airtrike gear-box. It is quality engineered - even if
it IS made in Russia.
The guy selling them knows his stuff and is very helpfull as well.

3 or 4 cyl Geo??
The 3 cyl needs the heavy flywheel, the 4 doesn't - making them the
same weight over-all and the 4 is 30% more powerfull. - and a LOT
smoother.

On Thu, 8 Jul 2010 18:09:15 -0400, "Buerste"
wrote:


"Sunworshipper" wrote in message
.. .
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

The liability would scare me!


I woudn't use V belts - a properly set up toothed belt perhaps on a 4
cyl - but the gearbox with the BMW cush-drive is the best setup.

On Thu, 08 Jul 2010 20:34:52 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tim Wescott fired this volley in news:-
:


Not just because it's for a plane -- if I knew the guy already I might
make a part or two. It's the fact that a couple of grooves in a pulley
morphed into a design/engineering task -- that means that the guy is
clueless, which means that you can't trust him to build the rest of the
plane right.

You don't have to trust him to build the plane; it's an experimental.
The _instant_ he puts a non-STC'd part on any aircraft, commercial or
otherwise, it becomes an experimental aircraft.


Not strictly true.

If it is on a certified plane, it becomes an ILLEGAL plane - but not
an experimental.
I, too, would turn down the task because the guy didn't have
specifications -- only hopes. But the liability risk is actually pretty
small. NTSC doesn't have jurisdiction over experimental craft, and
experimental pilots crack up all the time.

Of course, owners do all sorts of "custom" minor modifications to their
commercial craft: instruments, decorations, minor fittings like latches
and knobs. But the moment you modify the controls, the airframe, or the
powerplant (this pulley) you're off the chart, and on your own. And this
doesn't even seem to be a modification, but a build.

Mostly, I'd turn him down because he doesn't really know what he wants,
and not being an A&P mechanic myself, _I_ don't know what he wants,
either.

LLoyd (SEL pilot with about 1000 hours)

On Thu, 8 Jul 2010 16:19:44 -0700 (PDT), Dave__67
wrote:

On Jul 8, 5:29Â*pm, Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. Â*I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

They should have used a corvair engine- no speed reduction needed
(apparently)!

http://www.hainesengineering.com/rha...vair.htm#hubon


Dave
Correct - but with starter, alternator, exhaust and intake 265 lbs is
about "it"

On 07/08/2010 06:34 PM, Lloyd E. Sponenburgh wrote:
Tim fired this volley in news:-
:


Not just because it's for a plane -- if I knew the guy already I might
make a part or two. It's the fact that a couple of grooves in a pulley
morphed into a design/engineering task -- that means that the guy is
clueless, which means that you can't trust him to build the rest of the
plane right.

You don't have to trust him to build the plane; it's an experimental.
The _instant_ he puts a non-STC'd part on any aircraft, commercial or
otherwise, it becomes an experimental aircraft.

I, too, would turn down the task because the guy didn't have
specifications -- only hopes. But the liability risk is actually pretty
small. NTSC doesn't have jurisdiction over experimental craft, and
experimental pilots crack up all the time.

But it's not the NTSC that brings liability suits. It's the relatives
of the deceased, and the ambulance-chasers who find them.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

Dave__67 wrote:

They should have used a corvair engine- no speed reduction needed
(apparently)!

http://www.hainesengineering.com/rha...vair.htm#hubon

My goodness, I feel like such a slacker now!

Jon

Tim Wescott fired this volley in
news
But it's not the NTSC that brings liability suits. It's the relatives
of the deceased, and the ambulance-chasers who find them.

True enough, but it's already a precedent that anyone who (yes,
illegally, Clare) modifies a certified plane or builds an experimental is
entirely responsible for any ill that befalls him/her in that aircraft.
The courts have taken the stance over and over that if you jump off that
roof, I'm not responsible just because I built the roof you decided to
commit suicide from.

And Clare... if you modify a certified aircraft, you aren't illegal if
you pull its certification and have it re-inspected as an experimental
(or have the modifications subsequently certified). Had a friend who
used to modify DC-3s and C-47s for a ten foot cargo door in the side.
(which was a MAJOR chop-job to the airframe) Since he was selling them to
Columbians (for _cargo_... now, what were you thinking!), he just had
them re-listed as privately-owned experimentals, and let the Columbian
aviation officials worry about certification matters.

LLoyd

On Thu, 08 Jul 2010 23:19:36 -0400, wrote:


I woudn't use V belts - a properly set up toothed belt perhaps on a 4
cyl - but the gearbox with the BMW cush-drive is the best setup.

V belts seem to be time-tested on the Rotorway. Some info here
http://www.epi-eng.com/rotorway_heli...belt_drive.htm.
I didn't realize that the belts were tied together in pairs. Anyway,
it seems like most use toothed belts. Harder for an amateur to
machine, but lighter and less friction than V belts I presume.

Wayne

On Fri, 09 Jul 2010 09:02:05 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tim Wescott fired this volley in
news
But it's not the NTSC that brings liability suits. It's the relatives
of the deceased, and the ambulance-chasers who find them.

True enough, but it's already a precedent that anyone who (yes,
illegally, Clare) modifies a certified plane or builds an experimental is
entirely responsible for any ill that befalls him/her in that aircraft.
The courts have taken the stance over and over that if you jump off that
roof, I'm not responsible just because I built the roof you decided to
commit suicide from.

And Clare... if you modify a certified aircraft, you aren't illegal if
you pull its certification and have it re-inspected as an experimental
(or have the modifications subsequently certified). Had a friend who
used to modify DC-3s and C-47s for a ten foot cargo door in the side.
(which was a MAJOR chop-job to the airframe) Since he was selling them to
Columbians (for _cargo_... now, what were you thinking!), he just had
them re-listed as privately-owned experimentals, and let the Columbian
aviation officials worry about certification matters.

LLoyd

Cannot be done any more LLoyd. Can't even rebuild a certified doing
51% and get it passed as experimental any more - in Canada due to
interference by the US FAA who won't let such a plane fly in US
airspace.

Even the V6 STOL, which was a modified TriPacer with a Ford (Javelin)
V6 is a stretch under current regulations as an experimental.

An STC (Supplimental Type Certiificate) is required for any such mods
- and THOSE do not come cheap.

Selling into Columbia is definitely a different situation.

On Jul 8, 5:29*pm, Sunworshipper wrote:
Well, got myself in a pickle this time. I answered an ad with some guy
wanting lathe work done, he said it was a couple of groves in pulleys.
Come to find out he wants me to design, engineer, and build a speed
reducer for a Geo Metro engine powered hmmm plane. I'm not sure, but
I'm starting to think that my Atlas lathe won't be able to turn 8"
dia. V groves.

Anyhow, I've been searching the net to the point of getting a
headache. Seems this kind of stuff is hush hush. *I assume they run
off a spindle somehow bolted to the block and then an extension is
bolted on to get the prop past the distributor.

The cheapest I can find is $269.38 for the 5 belt 8" pulley and
$123.70 for the 5 belt 3" pulley.

Has anyone done this kind of thing before? The more I think about it
the more I should decline. I'm afraid I might miss something
important, like the vibration between the engine and air turbulence
affecting the triple prop. with aluminum between. Maybe it is just me,
I grew up around aircraft that were build by companies from J-3's to
DC-3's

While searching I see something that looks a lot more safe, an
Airtrike gear box for $2G. The cog ones seem safer than multiple belts
to me cause if ya loose one belt it's gonna take out the distributor
or the coil wire, what's the difference? The other names I have are
J bird and Raven. I see they use cog drives on super chargers, but
nothing 8" dia.

Anybody have any ideas I can help this guy out with? BTW, he's
computer illiterate, I thought I could help at least in that area, but
running into brick walls.

SW wishing he was making his own plane. 31 years since solo.

Just google General Aviation Product Liability and you will run, not
walk, to the nearest exit.

wrote:
On Thu, 08 Jul 2010 23:19:36 -0400, wrote:


I woudn't use V belts - a properly set up toothed belt perhaps on a 4
cyl - but the gearbox with the BMW cush-drive is the best setup.

V belts seem to be time-tested on the Rotorway. Some info here
http://www.epi-eng.com/rotorway_heli...belt_drive.htm.
I didn't realize that the belts were tied together in pairs. Anyway,
it seems like most use toothed belts. Harder for an amateur to
machine, but lighter and less friction than V belts I presume.

The one Robinson R-22 that I got a close look at
many years ago used 2 parallel V-belts to couple
the engine to transmission.

fired this volley in
:

Cannot be done any more LLoyd. Can't even rebuild a certified doing
51% and get it passed as experimental any more - in Canada due to
interference by the US FAA who won't let such a plane fly in US
airspace.

I haven't tracked that sort of stuff in years, since I'm not flying much
anymore, and only rental planes. Are you saying it's illegal in Canada,
or by virtue of being illegal in the US, Canadians can't do it too?

It used to be possible to privately modify pretty much _anything_ without
STC'ing the changes, then re-inspect as experimental.

(Yeah... I know about the costs of STCs. I have one of those famous #2
yellow pencils from PanAm in my flight bag. They're said to have been
worth almost $400 each the first few years they were issued to flight
crews).

LLoyd

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On Friday, July 9, 2010 at 10:02:05 AM UTC-4, Lloyd E. Sponenburgh wrote:
Tim Wescott fired this volley in
news
But it's not the NTSC that brings liability suits. It's the relatives
of the deceased, and the ambulance-chasers who find them.

True enough, but it's already a precedent that anyone who (yes,
illegally, Clare) modifies a certified plane or builds an experimental is
entirely responsible for any ill that befalls him/her in that aircraft.
The courts have taken the stance over and over that if you jump off that
roof, I'm not responsible just because I built the roof you decided to
commit suicide from.

And Clare... if you modify a certified aircraft, you aren't illegal if
you pull its certification and have it re-inspected as an experimental
(or have the modifications subsequently certified). Had a friend who
used to modify DC-3s and C-47s for a ten foot cargo door in the side.
(which was a MAJOR chop-job to the airframe) Since he was selling them
to Columbians (for _cargo_... now, what were you thinking!) ...

Well, I'm sure they say the same thing about pilots in Florida too, now don't they?