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[email protected] March 7th 05 03:28 AM

prop test engine- cheap
 
What have folks found to be the cheapest engine to swing a prop for
function and reliability testing? Needs about 100 hp at 2500rpm with
maybe a little extra up to 2800rpm. I would rather not go direct drive
if I can help it but that might be the cheapest way.

I thought about jacking my truck up and using a shaft off of the
driveline in some sort of big steel fixture. Now that would be
interesting. Heck, I could make a barge for my truck and "drive" it
around the lake like a big airboat :)

Seriously though, what's the cheapest option out there?

Joa


MikeR March 7th 05 03:36 AM


wrote in message
oups.com...
What have folks found to be the cheapest engine to swing a prop for
function and reliability testing? Needs about 100 hp at 2500rpm with
maybe a little extra up to 2800rpm. I would rather not go direct drive
if I can help it but that might be the cheapest way.

I thought about jacking my truck up and using a shaft off of the
driveline in some sort of big steel fixture. Now that would be
interesting. Heck, I could make a barge for my truck and "drive" it
around the lake like a big airboat :)

Seriously though, what's the cheapest option out there?

Joa


How about a junkyard motor?



Jan Carlsson March 7th 05 07:18 AM

If you want to test a prop, for reliability, you must test it with that sort
of engine it is supposed to be on, for vibration reasons.

Jan Carlsson
www.jcpropellerdesign.com

skrev i meddelandet
oups.com...
What have folks found to be the cheapest engine to swing a prop for
function and reliability testing? Needs about 100 hp at 2500rpm with
maybe a little extra up to 2800rpm. I would rather not go direct drive
if I can help it but that might be the cheapest way.

I thought about jacking my truck up and using a shaft off of the
driveline in some sort of big steel fixture. Now that would be
interesting. Heck, I could make a barge for my truck and "drive" it
around the lake like a big airboat :)

Seriously though, what's the cheapest option out there?

Joa




[email protected] March 8th 05 06:27 PM

Yes, it will definitely get tested later on the correct engine. I want
to do an initial run to veryify a few things first though.

What 100hp junk-yard engine could be readily adapted to a prop but not
have nasty torsional issues?

Joa


Jan Carlsson wrote:
If you want to test a prop, for reliability, you must test it with

that sort
of engine it is supposed to be on, for vibration reasons.

Jan Carlsson
www.jcpropellerdesign.com



Corky Scott March 8th 05 07:14 PM

On 8 Mar 2005 10:27:24 -0800, wrote:

Yes, it will definitely get tested later on the correct engine. I want
to do an initial run to veryify a few things first though.

What 100hp junk-yard engine could be readily adapted to a prop but not
have nasty torsional issues?

Joa


Think about it Joa, a four stroke cycle flat four produces a power
stroke every 180 degrees of crankshaft rotation. On a V8 the power
stroke occurs every 90 degrees of crankshaft revolution.

Now add to the mix the size of the cylinders. The O-360 is 90 cubic
inches of impulse for each combustion. The 350 cid V8 is 43.75 cubic
inches per cylinder, less than half the per cylinder cid of the big 4.
Bigger cylinders make bigger impulses.

You'll be running direct drive so PSRU reduction ratios aren't a
factor.

Which of the above engines do you think will produce the biggest
tortional impulse to the propeller? 360 cid four, or 350 cid V8?

Corky Scott

[email protected] March 9th 05 12:35 AM

On 8 Mar 2005 10:27:24 -0800, wrote:

Yes, it will definitely get tested later on the correct engine. I want
to do an initial run to veryify a few things first though.

What 100hp junk-yard engine could be readily adapted to a prop but not
have nasty torsional issues?

Joa


Jan Carlsson wrote:
If you want to test a prop, for reliability, you must test it with

that sort
of engine it is supposed to be on, for vibration reasons.

Jan Carlsson
www.jcpropellerdesign.com

An old smallblock chevie, or an old slant six, or even an old 230
chevy - they are still a dime a dozen in some areas.


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