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Robert Reynolds

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Jun 30, 2008, 5:36:13 PM6/30/08
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I posted a couple of new articles on my website at
www.balsaworkbench.com. One of them involves propeller guides for 2
stroke and 4 stroke engines. I don't know the original source for these
charts, and I don't have a lot of experience with engines larger than a
.91 four stroke. I welcome any suggestions or corrections that might
improve the usefulness of the charts.

Robbie

Bob Cowell

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Jul 2, 2008, 11:41:42 AM7/2/08
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Your charts look pretty "normal" to me ;-)

I would add a disclaimer that props from different manufacturers vary widely in
their performance.

THE single BEST 16x8 I ever laid hands on was an ancient "RevUp"
I have been buying and trying different brands and styles ever since I broke it.

For the .40 size, PLAIN BEARING ENGINE, a 10x5 APC seems to be a pretty good
match for those big draggy trainers.

for the .91 size four strokes, a nice 13x8 or 13x9 gives more speed
{for those who like more speed ;-) }
without lugging or losing too much in the low speed thrust department.

My OPINIONS
YMMV

bob

Robert Reynolds

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Jul 2, 2008, 2:21:51 PM7/2/08
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Bob Cowell wrote:
> On Mon, 30 Jun 2008 15:3

> Your charts look pretty "normal" to me ;-)
>
> I would add a disclaimer that props from different manufacturers vary widely in
> their performance.
>
> THE single BEST 16x8 I ever laid hands on was an ancient "RevUp"
> I have been buying and trying different brands and styles ever since I broke it.
>
> For the .40 size, PLAIN BEARING ENGINE, a 10x5 APC seems to be a pretty good
> match for those big draggy trainers.

> bob


It's funny you say that, because I use those plain bearing 40 engines
all the time, and the 10x6 is about as much prop as you would ever put
on one. 9x6 or 10x5 would be better, depending on the plane you're
powering. I have a Cloud Dancer with a 40FP and a 10x5, and it's just
right.

When I was punching in all those numbers for the charts my mind started
to wander. I should have thought of that one myself.

The Natural Philosopher

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Jul 3, 2008, 3:46:55 PM7/3/08
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Robert Reynolds wrote:
>
>
> Bob Cowell wrote:
>> On Mon, 30 Jun 2008 15:3
>> Your charts look pretty "normal" to me ;-)
>>
>> I would add a disclaimer that props from different manufacturers vary
>> widely in
>> their performance.
>>
>> THE single BEST 16x8 I ever laid hands on was an ancient "RevUp"
>> I have been buying and trying different brands and styles ever since I
>> broke it.
>>
>> For the .40 size, PLAIN BEARING ENGINE, a 10x5 APC seems to be a
>> pretty good
>> match for those big draggy trainers.
>
>> bob
>
>
> It's funny you say that, because I use those plain bearing 40 engines
> all the time, and the 10x6 is about as much prop as you would ever put
> on one. 9x6 or 10x5 would be better, depending on the plane you're
> powering. I have a Cloud Dancer with a 40FP and a 10x5, and it's just
> right.
>

I had a 40 cub and it flew great on a PB os40 on an 11x4...

If I were to do it again it would be on about half that power and
electric and a 12x8 or 13x10.

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