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Old May 08, 2012, 01:16 PM
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Gemini2's Avatar
United States, NJ
Joined Aug 2011
190 Posts
Question
Folding Prop Substitution for Fixed - Questions

I first posted this over at NoFlyZone's blog a week or so back, but it looks like he really is on vacation, so I will try my luck here.


I will be building an Old Time converted FF rubber model with a direct drive & folding prop for slow stooging around & now & then heading way up, cutting the motor & letting the thermals take over.

I have run the data through Webocalc 1.5.2 & got to the magic '1.00 Approx gear ratio', for 2 fixed props.

I haven't figured how to get the Webocalc image up here, so I have the core left hand side data [imperial] from Webocalc, as follows:

RTF Weight: 28 oz; WS: 64"; WA: 464; MPS: 15, FM: Gentle; DTS: 36, DT: 21, ME: Avge Outr, 75%; Batt: L 3S 20C; BV: 10.8, DCM: 8.7; KV: 570

This pops out the APC-TE 12.0 x 8.0 & the GWS-HD 12.0 x 8.0 with the "1.00" AGR.

Now, I am looking at the Aeronaut Cam folding prop range & wonder if I can put a pair of 12.0 x 8.0 blades (AN-7234-50), on a 52mm yoke & that will be the best I can do??

Or whether using a 52mm yoke means I need to tweak the blades away from the 12.0 x 8.0's to compensate for yoke size??

Or, are there any other factors associated with using a folding prop ilo of a non folder I should consider in prop choice??

Thank you

G2
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Old May 08, 2012, 08:32 PM
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Bruce Abbott's Avatar
Hastings, New Zealand
Joined Jan 2001
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Using a 52mm yoke increases prop diameter by 0.4 inches (compared to a 42mm yoke) which will cause about 8% higher current draw. If your motor and ESC can handle this then it shouldn't be a problem, otherwise use 12x6.5 blades.
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Old May 09, 2012, 08:40 AM
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United States, NJ
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Quote:
Originally Posted by Bruce Abbott View Post
Using a 52mm yoke increases prop diameter by 0.4 inches (compared to a 42mm yoke) which will cause about 8% higher current draw. If your motor and ESC can handle this then it shouldn't be a problem, otherwise use 12x6.5 blades.
Thanks Bruce, exactly what I was looking for.

G2
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