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Prop size, Fuselage diameter!!

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Old 09-19-2006, 07:53 AM
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ho0joker
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Default Prop size, Fuselage diameter!!

Hi.. I have a somewhat technical question..
Is it neccessary for the prop to clear the fuslage in order for the plane to fly properly?? I mean is it neccessary that the prop diameter be obviously larger than the fuselage.. I have a stong brushless motor (28-45-2700kV) which When run on a 3s lipo and a 5" prop can be handeled by my 25amp ESC.. Can I fly my 42" plane with it if the thrust is equivalent to or more that of the recomended motor with a larger prop.. They recommend a 1000kV motor, 3s lipo and 11" prop..
What do you guyz think???[&o]
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Old 09-19-2006, 09:18 AM
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Default RE: Prop size, Fuselage diameter!!

I think you are going to have a hard time flying with a 5" prop. With a 2700kv motor you should start testing props around a 10x6 or 10x8 and go from there. The best way to tell amp draw is to get a power meter or amp meter that will go up to like 40 amps. Are you trying to justify going with a smaller prop because your motor is bigger than the recommendations? Also, I am not completely sure that a 25amp ESC will handle that motor to begin with. What is the amp range of the motor, both contiuous and burst?
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Old 09-19-2006, 03:08 PM
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Default RE: Prop size, Fuselage diameter!!

Thanks for replying..
I guess I'm trying to get awya with as less cost as pssible :P
Max constant current 28amp, burst not sure!!
I think you're right.. I will get over my feeling and spend some more
I will order the GreatPlanes 45amp ESC just in case I have an even hotter motor..
Do you know where I can find an online shop that sells those ammeters for a low price..? or should I just go ahead with the 45amp ESC and that's it?
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Old 09-19-2006, 04:12 PM
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Default RE: Prop size, Fuselage diameter!!

So-called "wattmeters" are available starting at about $50. If you plan to continue with electric flight, you'll definitely want one.

Here's a good basic model:
http://www.bphobbies.com/view.asp?id...07&pid=U054250

- Jeff
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Old 09-19-2006, 04:43 PM
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Default RE: Prop size, Fuselage diameter!!

A 45amp ESC should more than cover you, but I agree witht he previous post, you really need a wattmeter or power meter. I use this one

http://www.horizonhobby.com/Products...ProdID=EFLA110
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Old 09-20-2006, 07:18 AM
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Default RE: Prop size, Fuselage diameter!!

Thanks guyz.. I will buy one.. The two sites you recommended do no accept international orders
I am used to ordering from tower hobbies but they seem not to have one.. I will double check..
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Old 09-20-2006, 07:20 AM
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Default RE: Prop size, Fuselage diameter!!

I was wrong they do have one..
http://www2.towerhobbies.com/cgi-bin...&I=LX3605&P=ML
I guess this one will do the job
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Old 09-20-2006, 10:24 AM
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Default RE: Prop size, Fuselage diameter!!

ORIGINAL: ho0joker

I was wrong they do have one..
http://www2.towerhobbies.com/cgi-bin...&I=LX3605&P=ML
I guess this one will do the job
That's the exact Whattmeter I own, and it works great. It appears that Tower supplies the unit with Astro-Flight Zero-Loss connectors, so you'll have to replace them with whatever connectors you use on your batteries and ESCs (or purchase a set of the Zero-Loss connectors and make yourself a pair of adapters).

- Jeff
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Old 09-22-2006, 05:04 AM
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Default RE: Prop size, Fuselage diameter!!

I'll just replace them withe deans I guess.. Thanks a lot JDETRAY
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