ThrustHP a Little Optimistic?  
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All Forums >> RC Airplanes >> Scratch Building, Aircraft Design, 3D/CAD >> ThrustHP a Little Optimistic?
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ThrustHP a Little Optimistic? - 4/17/2002 9:05:22 AM   
Joe Petro


 

Posts: 264
Joined: 2/24/2002
From: Utica, NY, USA
Status: offline 		I have been using the ThrustHP program for some time now, and I think it's just a little unrealistic when it comes to estimating thrust.

Maybe it figures 100% (prop) efficiency?
It seems to get worse as prop size increases. I have found that the .46 size planes need about 1.3 times thrust/weight to even "hang" on the prop, and at least 1.5 to hover.

That seems just a bit high, don't you think?

I know, there are too many variables, etc. But when I am planning a new design, I would rather be a little low on thrust estimates than high.

Nit picking? You tell me...

Anyone else?

Thanks,
Joe

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       Post #: 1

Seems close to me. - 4/17/2002 12:57:28 PM   
JohnW



Posts: 1770
Joined: 3/22/2002
From: Lincoln, NE, USA
Status: offline 		I have used the ThrustHP Version 2.0d and it seems to get pretty close. For example, I have a 11lb plane spinning a APC 16x12 at ~9000, Thrust HP claims 16lbs of static thrust. The plane has unlimited vert and I have enough thrust to punch out windmils and waterfalls. It "feels" like about 1.5:1 which is what Thrust HP claims. Have a 28lb plane spinning a 28x10 at 6K which gives me 66lbs of thrust, or about 2:1 thrust/weight which also seems about right for that plane.

However, I have never measured the actual static thrust (other than flying) so I don't really know.

I would agree that you really need about 1.5:1 to hover easily. If it was me, I would error on the side of caution, i.e. figure that the Thrust HP is a bit optimistic.

(in reply to Joe Petro)
       Post #: 2

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All Forums >> RC Airplanes >> Scratch Building, Aircraft Design, 3D/CAD >> ThrustHP a Little Optimistic?
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