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Oct 02, 2019, 09:36 PM
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radfordc's Avatar
Which warbird? I use the similar Tacon 160 motor in a couple of 80" span fighters...Corsair and P-40. I run 8s 5000 packs and get 6-7 min of good performance. The Corsair uses a two blade 20x10 cut down to 18".

Corsair with HVAR rockets mounted (7 min 12 sec)
Latest blog entry: Assembling a Spandau kit.
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Oct 02, 2019, 09:39 PM
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radfordc's Avatar
P-40 uses the same setup but with a Ramoser 3 blade Varioprop

P 40 first flight (4 min 48 sec)
Latest blog entry: Assembling a Spandau kit.
Oct 03, 2019, 04:10 AM
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Phoenix P-40. Should weigh about 15lbs on the ground. I do not want it to be a speed demon or have a super high RPM prop, I want it to fly scale and sound good.

I'm really just scrambling to get it together for the warbird fly in 3 weeks right now after our club's VP asked if I'd have it done since we don't really have any "giant scale" warbirds at our small Spanish club.

Webocalc has this 6S, 21x13 combo making 235oz of thrust with a 62.8mph vpitch. If I were to prop it at 20x15 it would be 211oz of thrust and 70mph vpitch. That gets me close to 75mph vpitch but I lose like a pound and a half of thrust.

I'll see how it flies. First flights are going to be lazy maidens anyway if it sucks and is severely underpowered I'll put this ESC in a new EDF I'm getting and buy the YEP 120v high voltage ESC and prop it at 18x10 on 10S. That'll put it at 280oz of thrust with a 73mph vpitch.
Oct 03, 2019, 04:13 AM
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Quote:
Originally Posted by scirocco
Power and static thrust might look OK, but at the low max rpm you're going to get with 6S and only 290 rpm/V your pitch speed will be on the low side, especially for a warbird.

You'd want at least 15" pitch on 6s and 12" on 8S to get about 75mph pitch speed. Much less and the model will feel sluggish in flight.
I could try a 21x15 prop if I can find one that doens't cost an arm and a leg. Doesn't seem like a very common size...
Oct 03, 2019, 07:39 AM
Registered User
Nevermind, I educated myself a little. RPM divided by 1080 then multiplied by pitch=vpitch mph. 21x13 actually comes out to like 59mph math wise... I don't want the plane to fall out of the sky... Motion only had one 20x15 prop so I ordered that and hopefully I don't faceplant the plane on the maiden lol. vpitch for that is 70.2mph.


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