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Old Nov 24, 2012, 02:56 PM
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United States, TX, College Station
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Originally Posted by TexasAggie View Post
I've been trying to decide between two motors for my Skywalker build. I'm going to run on 4S, so I'm shooting for about 1000kv. The two I've found are:

Firepower 30 (http://www.headsuprc.com/servlet/the...h-10%29/Detail)

Power Up 15 (http://www.headsuprc.com/servlet/the...5-Sport/Detail)

The first makes about 60 oz of thrust at about 28 A with 9x6 or 9x4.5.

The second makes a bit less: 56oz @ 32A. This motor also weighs nearly an ounce less.

The data seems to indicate that the first is more efficient, at least at full throttle. Though, it weighs more so any gain will likely be burned with the extra induced drag. Anyone have any thoughts?
The second motor is 42mm in diameter. I have a hunch this is too big for the motor mount. Can someone confirm this?
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Old Nov 24, 2012, 03:52 PM
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United States, MI, Detroit
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Quote:
Originally Posted by TexasAggie View Post
I've been trying to decide between two motors for my Skywalker build. I'm going to run on 4S, so I'm shooting for about 1000kv. The two I've found are:

Firepower 30 (http://www.headsuprc.com/servlet/the...h-10%29/Detail)

Power Up 15 (http://www.headsuprc.com/servlet/the...5-Sport/Detail)

The first makes about 60 oz of thrust at about 28 A with 9x6 or 9x4.5.

The second makes a bit less: 56oz @ 32A. This motor also weighs nearly an ounce less.

The data seems to indicate that the first is more efficient, at least at full throttle. Though, it weighs more so any gain will likely be burned with the extra induced drag. Anyone have any thoughts?
Since you're just putting together a new setup. Try to get a motor that will swing a 10x6 prop and pull 30A WOT. I'm guessing a motor in the 800-900KV on 4s will do that. That'll be the most efficient setup.
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Old Nov 24, 2012, 04:26 PM
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Sorry to hear about your bird man. My skywalker did the same thing.

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Originally Posted by Efti View Post
I have the failsafe on about 60% throttle, but the RTH did not engage all the time. I pulled up all I could, but nothing happened. Also put the throttle down. It is so strange.
Full throttle is somewere about 40Amps

Anyway the plane can't be fixed.

After 120KM/H it look like this....
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Old Nov 24, 2012, 06:08 PM
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Originally Posted by Efti View Post
I have the failsafe on about 60% throttle, but the RTH did not engage all the time. I pulled up all I could, but nothing happened. Also put the throttle down. It is so strange.
Full throttle is somewere about 40Amps

Anyway the plane can't be fixed.

After 120KM/H it look like this....

Man, that's a bummer. Hope you can rebuild! I would suggest setting the FS for 0 throttle. Can be dangerous to someone on the ground otherwise..
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Old Nov 24, 2012, 07:41 PM
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Originally Posted by ashdec87 View Post
Since you're just putting together a new setup. Try to get a motor that will swing a 10x6 prop and pull 30A WOT. I'm guessing a motor in the 800-900KV on 4s will do that. That'll be the most efficient setup.
The reason being that a 6" pitch is ideal and a 10" spinning more slowly than a 9" will be more efficient for the same amount of thrust? Problem is, I don't see any electric 10x6 props. I'd rather sacrifice a bit of efficiency to have readily available parts.
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Old Nov 24, 2012, 09:00 PM
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Originally Posted by TexasAggie View Post
Problem is, I don't see any electric 10x6 props. I'd rather sacrifice a bit of efficiency to have readily available parts.
I run an APC folding 10x6, meant for electrics.

ian
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Old Nov 24, 2012, 09:27 PM
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I run an APC folding 10x6, meant for electrics.

ian
I know; I've been reading. That's just another thing that I'd rather not mess with, though.
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Old Nov 25, 2012, 07:56 AM
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What kinda deflection do you guys have on the ailerons?
Standard horns on the CS929MG seem a little short, I can only get 15mm down & 30mm up before things bind and I would like to use flaperons...
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Old Nov 25, 2012, 09:09 AM
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United States, MI, Detroit
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Originally Posted by TexasAggie View Post
The reason being that a 6" pitch is ideal and a 10" spinning more slowly than a 9" will be more efficient for the same amount of thrust? Problem is, I don't see any electric 10x6 props. I'd rather sacrifice a bit of efficiency to have readily available parts.
Found one

http://www.hobby-lobby.com/10x6_apc_...ueryId=4041446

And yes, the 6" pitch flies the plane at roughly the right speed 25-35mph, and the slower the prop spins the more efficient it is. Quieter too.
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Old Nov 25, 2012, 09:43 AM
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Originally Posted by ashdec87 View Post
Found one

http://www.hobby-lobby.com/10x6_apc_...ueryId=4041446

And yes, the 6" pitch flies the plane at roughly the right speed 25-35mph, and the slower the prop spins the more efficient it is. Quieter too.
Wow. I had no idea that existed. Nice find!
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Old Nov 25, 2012, 02:05 PM
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Originally Posted by ashdec87 View Post

And yes, the 6" pitch flies the plane at roughly the right speed 25-35mph, and the slower the prop spins the more efficient it is. Quieter too.
http://innov8tivedesigns.com/Scorpio...90%20Specs.htm

Interesting that in this case, the 10x6 is less efficient in terms of thrust / power than the 9x6.

According to the data, the 10x5 looks like a good choice for this motor. However, WebOCalc argues that the 10x6 is a slightly better fit. Nothing is cut and dry...
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Old Nov 25, 2012, 02:39 PM
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Last edited by mich75; Nov 25, 2012 at 03:03 PM.
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Old Nov 25, 2012, 06:12 PM
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Originally Posted by mich75 View Post
What kinda deflection do you guys have on the ailerons?
Standard horns on the CS929MG seem a little short, I can only get 15mm down & 30mm up before things bind and I would like to use flaperons...
That is more than enough. I have about 10mm down and 17 up and can easily do rolls with aileron only. I use flaps as flaps because my OSD won't let me have two aileron channels or flaperons.
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Old Nov 25, 2012, 06:22 PM
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United States, MI, Detroit
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Originally Posted by TexasAggie View Post
http://innov8tivedesigns.com/Scorpio...90%20Specs.htm

Interesting that in this case, the 10x6 is less efficient in terms of thrust / power than the 9x6.

According to the data, the 10x5 looks like a good choice for this motor. However, WebOCalc argues that the 10x6 is a slightly better fit. Nothing is cut and dry...
Ah but see the thing is that you would want to keep the amps roughly the same for both props. The 9x6 is drawing 24 amps, 10x6 is pulling 33. So just ball parking, you'd want a motor with 1000kv for a 9x6 prop vs. a 800kv for a 10x6. Its not necessarily more thrust, but its done more efficiently.
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Old Nov 26, 2012, 03:54 PM
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Right - bought this yesterday. Going to run 2 x 5800 4s with D3542 -1000k. Using a Aeronaut 9x7 folding prop
1 x 38mm centerpiece.
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