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Old 12-29-2006, 08:16 AM
jamesrd is offline
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ONE BLADE PROP!!!!

I know this might sound dumb to ask, but I will ask anyway. Has anyone heard of where I can find information on the efficiency of a one blade prop vs 2 or more blades? I have done some searching and can't find anything. I have heard rumor of a one blade being most efficient. But I am not sure of that. Thank you for your help!!!!!!!!!!

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Old 12-29-2006, 08:22 AM
SleepyC is offline
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Re: ONE BLADE PROP!!!!

A one blade prop?

The vibration would blow the plane apart!

Do you mean a 2 - blade prop vs. a 3 blade?
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Old 12-29-2006, 08:25 AM
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Re: ONE BLADE PROP!!!!

HI pilon races use them props & from what i have seen there are realy only for that type of plane.a aerobatic plane would not work that great with a 1 blade prop,
if you search google for that type of plane you might have some luck
hope this helps
cheers glen
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Old 12-29-2006, 08:26 AM
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Re: ONE BLADE PROP!!!!

Years ago , the free flighter's were using one bladed props for just that reason, One blade and a weight on the other side for balance. They may still be using them, check out old "Model Aviation " mags from AMA.
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Old 12-29-2006, 08:30 AM
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Re: ONE BLADE PROP!!!!

Quote:
One blade and a weight on the other side for balance.
Ahhhhhhhhhh. Ok that makes more sense.
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Old 12-29-2006, 08:31 AM
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Re: ONE BLADE PROP!!!!

CL speed folks will use one blade props as well.


JSI,
50%
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Old 12-29-2006, 08:40 AM
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Re: ONE BLADE PROP!!!!

Propellers have one, two, three or four blades. Single blade propellers are counter-balanced and used on extremely high rpm racing motors. I've never seen these sold anywhere and suspect they are built by the user. You don't need to even think about these props unless you're building control line speed aircraft. In fact, they may not even be used any more. I haven't been paying attention.
In our realm, the most efficient propellers are two bladed. Because the diameter of our propellers is so small, multiple blade propellers disturb the air that the trailing blade is entering. Therefore, 3 and 4 blade propellers are less efficient.
In general, the only time a 3 or 4 blade propeller should be used is for a more scale appearance or when a smaller propeller disk is necessary.
For example, a scale, twin-engine aircraft may not be able to swing a 2-blade propeller of a small enough diameter to clear the sides of the fuselage. A three and four blade prop can be used here because it can be a smaller diameter and present the same load on the engine. For best performance with sport aircraft, stick to 2-blade propellers.


I have only seen a handfull of these myself but if you look at the record holder for control line alot of them use this style of prop.
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Old 12-29-2006, 08:40 AM
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Re: ONE BLADE PROP!!!!

well, you heard right a one blade prop is the most efficient and used by the hand controlled speed racers - the prop is counter balanced - the excact theory behind it I am not sure - now with our planes I have tested two blade and three blades on my 150 and there is a definate power diff with the two blade being much stronger - I am sure you will get some input from some of the big guys related.

i found this on google -

The most efficient propeller is one blade with a counterweight on the other side. Next most efficient is two blades, followed by three, then four, etc.

The real reasons to go to more blades are two:

1) There comes a point where the diameter of the propeller at the RPM in question approaches the sound barrier. You thenm opt for more blades at a lesser diameter to slow the prop tips.

2) There comes a point where the power to be absorbed by the propeller requires more blades or an increase in diameter that causes a) supersonic or transonic tips or b) unacceptable loss of ground clearance. (It is WAY easier to design a shorter prop than to fit longer landing gear)
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Old 12-29-2006, 08:43 AM
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Re: ONE BLADE PROP!!!!

sailplanes also use one blade props for the retractable pylon type of self launch systems...
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Old 12-29-2006, 08:52 AM
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Re: ONE BLADE PROP!!!!

Quote:
Originally Posted by Toro View Post
sailplanes also use one blade props for the retractable pylon type of self launch systems...
Thats kind of a buzzz kill Toro, go from SPEED planes using them to sailplanes.......wth?

do you pee in the punch at parties too?






bahahahaha
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Old 12-29-2006, 08:56 AM
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Re: ONE BLADE PROP!!!!

yes there is a group of guys in aus that make there own i was just told by a mate thats siting next to me,i have seen there planes go only a few weeks ago & were doing 300kmh+ rosi motors there nuts & love speed.
cg
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Old 12-29-2006, 08:58 AM
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Re: ONE BLADE PROP!!!!

here a pic of a one blade bolly CF prop
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Old 12-29-2006, 09:00 AM
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Re: ONE BLADE PROP!!!!

I think there were some pictures of CL planes in one of the last Model Aviation issues with one blade props. Might have even been the last issue, but I forget.

Jay
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Old 12-29-2006, 09:02 AM
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Re: ONE BLADE PROP!!!!

Quote:
Originally Posted by adrian View Post
here a pic of a one blade bolly CF prop

lol adrian aka mr avater thats the pic i just got funny that & pt props make them & dbl props to 1 in front of the other for electric set ups
cheers glen
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Old 12-29-2006, 09:11 AM
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Re: ONE BLADE PROP!!!!

lol - sorry bro - i am searching the net on one bladed prop theory - all the stuff is on ww2 planes
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