AN ENGINE FOR HOMEBUILDERS

"Dan" wrote in message
...
vaughn wrote:
"cavelamb" wrote in message
m...
Stuart Fields wrote:
so what do I call it?
A Stuart 0320?

LycoFields 0320?

90% O320 = O288?

Dan, U.S. Air Force, retired

To Cavelamb, Dan and Vaughn, thanks you've given me a good idea. Every year
the county asks me to fill out a form with information about my aircraft so
they can assess a 1% Personal property tax, they always ask what the engine
is. I now have some new ideas how to answer that question more accurately.



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Great to hear of your improving health Bob. You helped me in the past
and I follow your blog regularly. Thanks for your help and incredible
advice.

Here's an idea I've been working on. Take 2 v-twin industrial engines
in the 20-25 hp range. Place 1 facing forward and 1 facing the rear.
Attach the props at the end of simple long belt (or motorcycle
chain?) psru's and short booms with the engines buried in the fuselage
and cooled by thier original system. The sailplane world and ppg
people have these systems now.

Counter rotating props, stock industrial engines, engines low for
crash protection on pusher UL configurations.

For direct drive applications the old Kolb UL method of 2 little
engines on short beams holds great promise.

One quick question, will a motorcycle chain system work for a prop?

One more quick thought about construction of cheap UL's in the asian
countries why not bamboo for structural material. If anyone has ever
been to the east and seen the incredible scaffolding surrounding high
rise buildings soon realizes that there is a lot of knowledge locally
on inspecting, choosing, and building structures out of bamboo. The
stuff is incredibly strong and light. It grows like a weed everywhere
and can be harvested easily. If I lived there I'd use it.

Of course I live in North America and plan on fir from a local lumber
yard, cheap luan marine plywood from a local canoe shop and mild steel
tubing with stainless cap screw fastners from reputable North American
suppliers. When I mention these plans I might as well be building
with bamboo and twine (check out Mr. Montforts ultralite boats) when
at a gathering of experimental airplane builders!

Wow!

Now that's what I was hoping to see.

Okay, maybe a PSRU using belts. But not vee-belts. There is two
examples of v-belt drives we can use to draw data from, the one on
the Headwind, another on the PL-4. Both call for some wizard
machining and both need matched sets of belts, in that v-belts stretch
and you end up with slippage. This was covered... 'way back when
sometime (and I've probably got the details wrong).

The folks at Valley Engineering (sp?) have shown us how to do it with
a cog-tooth belt... which may also apply to some sort of serpentine
arrangement.

Would a timing belt work? I usta have a Pontiac that had a belt-
driven cam...

I'm thinking more of the machining here rather than the belt, on the
assumption that a cog-tooth belt WILL work... the main question being
how LONG it will do so. Which brings to mind the mention of a rear
axel something. Turns out, the bearing used for a rear axle is NOT
suitable for any kind of prop-drive. Slow prop turns more than 1200
rpm whereas a fast rear wheel is something less than that. Kinda like
the belt problem... you have to keep changing the thing BEFORE it can
fail, which it will in fairly short order. Cost is probably another
factor that needs to be considered here, in that a bearing that WILL
hold up at prop-speeds is probably priced a lot higher than your basic
rear wheel bearing.

Then there's the problem of starting the thing. Direct-drive we can
tweak the timing so it will start at a flip of the prop. But put a
PSRU in there we've got to 'wind it up' to get it to the proper firing
point.

-----------------------------------------------------------------

I wish I had a shop full of TATA engines to play with. There may be a
combination of cam & rod-length that can give a reliable 40hp at an
rpm most suitable for a prop.

-----------------------------------------------------------------

Speaking of props, has anyone ever heard of one made from bamboo?

----------------------------------------------------------------

I've got to go. Zometa. IV. About a quart. Takes a while (drip-
drip-drip...) Then I gotta look at a faucet that is doing the same
thing (drip-drip-drip...)

-Bob

"Morgans" wrote in message
...

"Stealth Pilot" wrote

I think you're a bit pessimistic there.
arent robinson helicopters and schweitzer helicopters driven by a
stack of belts to the transmission.
surely they are more than 40Hp?

Don't know. Anyone?

How about some power transmission charts for v-belts from the
manufacturers. That might be of some help.
--
Jim in NC

Yes both the Robinson, Scweitzer and Helicycle helos have a stack of belts
in their drive train.

Stu. Experimental Helo magazine.



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Bob wrote:
Wow!

Now that's what I was hoping to see.

Okay, maybe a PSRU using belts. But not vee-belts. There is two
examples of v-belt drives we can use to draw data from, the one on
the Headwind, another on the PL-4. Both call for some wizard
machining and both need matched sets of belts, in that v-belts stretch
and you end up with slippage. This was covered... 'way back when
sometime (and I've probably got the details wrong).

The folks at Valley Engineering (sp?) have shown us how to do it with
a cog-tooth belt... which may also apply to some sort of serpentine
arrangement.

Would a timing belt work? I usta have a Pontiac that had a belt-
driven cam...


snip
According to the Valley web site, they are using a 'poly-V belt'. If you
look closely at the pics, you can see that the pulleys are multi-rib,
not cog.
http://www.valleyengineeringllc.com/big-twin.php

Charlie

"Charlie" wrote

If 40 hp will do it, the new 'industrial' engines are looking really good
at this point. I follow an email list that focuses on small 4stroke
engines for a/c, & most of the discussion lately has been about these
engines. One guy is converting a vertical shaft lawn tractor motor (~32
hp).

These engines aren't at the 40 hp level yet, but it's easy to see bigger
ones coming out in the future. The nice thing about an industrial engine
is the output shaft & bearing is usually designed to take the horrendous
side loads of a reduction drive, so an a/c reduction or prop bending load
shouldn't be too much of a problem, and they are designed for continuous
output, not intermittent or varying load like most engines.

The biggest drawback these engines seem to have is weight. The current
offerings in a two cylinder and about 25 to 30 HP go about 100 pounds,
right?
--
Jim in NC

"Stealth Pilot" wrote

I think you're a bit pessimistic there.
arent robinson helicopters and schweitzer helicopters driven by a
stack of belts to the transmission.
surely they are more than 40Hp?

Don't know. Anyone?

How about some power transmission charts for v-belts from the manufacturers.
That might be of some help.
--
Jim in NC

"Bob" wrote in message
...
Wow!

Now that's what I was hoping to see.

Okay, maybe a PSRU using belts. But not vee-belts. There is two
examples of v-belt drives we can use to draw data from, the one on
the Headwind, another on the PL-4. Both call for some wizard
machining and both need matched sets of belts, in that v-belts stretch
and you end up with slippage. This was covered... 'way back when
sometime (and I've probably got the details wrong).

I have a Gibson tractor that has 4 belts running the transmission. It is
not as much load as the 40 HP will put on the belts, but with enough belts,
the load would be close enough to work I think. I found that if 4 belts
were purchased from the same lot, it was well enough matched. The tight
belts would soon stretch to shed their load to the looser belts.

The folks at Valley Engineering (sp?) have shown us how to do it with
a cog-tooth belt... which may also apply to some sort of serpentine
arrangement.

The toothed belt has been done at high HP levels (over 200HP) and have been
shown to last well over 200 hours. My concern with a setup like this is the
expense and availability of the pulleys and belts, and the machining needed
to put the whole thing together. Not do-able, IMHO.

Would a timing belt work? I usta have a Pontiac that had a belt-
driven cam...

I think the belts on a timing belt are square profile, and the ones being
used in commercially available PSRU units are a rounded profile. I seem to
remember that the square profile belts wore badly, and got too hot to be
reliable.

I'm thinking more of the machining here rather than the belt, on the
assumption that a cog-tooth belt WILL work... the main question being
how LONG it will do so. Which brings to mind the mention of a rear
axel something. Turns out, the bearing used for a rear axle is NOT
suitable for any kind of prop-drive. Slow prop turns more than 1200
rpm whereas a fast rear wheel is something less than that. Kinda like
the belt problem... you have to keep changing the thing BEFORE it can
fail, which it will in fairly short order. Cost is probably another
factor that needs to be considered here, in that a bearing that WILL
hold up at prop-speeds is probably priced a lot higher than your basic
rear wheel bearing.

How about the wheel bearings used on those itty bitty trailer tires? They
turn a lot more RPM's. With a good oil supply (from the engine) they ought
to last for a couple hundred hours, then they are cheap enough to just
replace them.

Then there's the problem of starting the thing. Direct-drive we can
tweak the timing so it will start at a flip of the prop. But put a
PSRU in there we've got to 'wind it up' to get it to the proper firing
point.

Yep. Gotta have a starter.

I wish I had a shop full of TATA engines to play with. There may be a
combination of cam & rod-length that can give a reliable 40hp at an
rpm most suitable for a prop.

TATA?

Speaking of props, has anyone ever heard of one made from bamboo?

I can't imagine. Props need to be solid with no voids, and voids bamboo
gots plenty of! g

I've got to go. Zometa. IV. About a quart. Takes a while (drip-
drip-drip...) Then I gotta look at a faucet that is doing the same
thing (drip-drip-drip...)

You make it sound so tempting. I almost want to go out and get some for me!
;-)
--
Jim in NC

On May 21, 4:28*am, Brian Whatcott wrote:

...every four stroke has a 2:1 reduction drive built in.
One that's subject to really lumpy loads.
It's called the cam shaft drive. Beefing up this chain
or gear drive would be one way.....
-------------------------------------------------------------------------------------

Dear Brian (and the Group)

I tried this approach some years ago. I used an after-market steel
cam gear for my starting point and came up with approximately 1200
hours as the service-life, indicating a re-build would be required at
the 600 hour mark.

I began by turning the engine over. Upside down, it would require a
pair of out-board oil pumps, one for scavaging the oil from the heads
& crankcase and feeding it to a new oil sump, the second pump drawing
oil from the sump and feeding it to the engine for lubrication,
filtering, cooling and so forth.

The reason for inverting the engine was to give me full access to the
existing oil pump's location. An outboard bearing and thrust assembly
was designed for this opening. The propeller shaft was a spllined
unit, 1.25" in diameter. That part of the project was relatively
straight-forward, using a double-row ball bearing for both thrust &
prop shaft support.

I don't recall the details as to why I gave up on the project but it
had to do with the interface between the cam shaft and the cam gear.
This project was done in the early 1980's.

-R.S.Hoover