FT Racer (Slinger) Power System

[jsut210]

So, I'm planning on building a FT Slinger soon. I chose this one because I want to go fast . When I say I want to go fast I want to be able to really scream across the sky. So I was looking into what prop-motor-esc-battery to use in it. I'm thinking around a 9inch with a high pitch for speed. I was also hoping to put up a 2200 3 cell for the battery. Also I have a few 30A ESCs handy so I would like to use them. All this being said, what's the best motor for the money that will work for this plane? I was hoping to not spend more than 20$ for a motor too. I looked at the GT2215/09 or "The Beef" from lazertoys and saw that they bundled that with a 9x6 prop for the swappable. But it looks like the next step up is the GT2218/09. If I got this motor, what prop should I use for the best speed? They used an 11x3.8 in their tests but I don't think that a slow fly prop would give me what I'm looking for.

 

[jsut210]

OOPS! I think this should go in the swappable thread..Sorry! Not sure if I can move it?

 

[xuzme720]

For speed you'll want a smaller diameter prop and a higher Kv motor. The big diameters are more for pulling and end up being pretty slow (relative) but get moving really fast from a dead start. For top speed you'll want less of the low end power, so you want a prop with a smaller bite and a faster spinning motor. It seems backwards but it's like gearing in a car. Big diameter props/low Kv motors are like first or second gear and smaller props/high Kv motors are 4th or 5th gear.
Does that help? I know I haven't given you an exact combination but I haven't built the Slinger yet so I'd be guessing at what will give you top speed on it...

 

[chaos23]

would this work for you? the user comments below have guys running 11" and 10" props. not recommended, like xuzme720 said smaller means faster spin and usually more thrust. tunigy motors are good strong motors and like the user comments say people are running props far beyond the motors rec specs

https://www.hobbyking.com/hobbyking...K3_3530_1460kv_Brushless_Outrunner_Motor.html

 

[jsut210]

I think that a 10 inch prop might be a little large for this application... Also, that motor is just a bit out of my price range. Does anyone know what motor they used in the video? Those are the speeds I am looking for.

 

[jsut210]

How do you think this motor would do with a 8x6 or even a 9x6 prop and a 50A esc? http://www.hobbyking.com/hobbyking/...Series_35_30A_1400kv_560w_USA_Warehouse_.html

Would it be better to go to say an 8x8 rather then a 9x6?

 

[chaos23]

Thats a good motor, but 50a esc would be to much. As for props grab one of each and do some trial and error. I order 11x4.7 and 12x4.5 for my quad to see the dif. But a 9x6 is good and an 8x8 is a safe bet.

 

[jsut210]

Hmm, the only prop with a bigger pitch like that in the US warehouse is this 9x8 http://www.hobbyking.com/hobbyking/store/__20294__Master_Airscrew_propeller_9x8_USA_Warehouse_.html
Do you think this is pushing it too hard? Should I just stick with the 9x6 or 8x6? I also found this: http://www.hobbyking.com/hobbyking/store/__20265__Master_Airscrew_propeller_8x7_USA_Warehouse_.html

 

[Foam Addict]

Use the 50a ESC, don't go smaller. That is a seriously powerful motor. Try a 9x6 first to get a feel for the plane, then try an 8x8 after a flight or two, those 8x8s take some speed to start producing thrust, and need a really good launch.

 

[Flat4]

I'm running that motor in a bloody wonder with an APC 9x6 on a 2200 3S, and a dynam 60amp esc, and it def pulls it along nicely. I've even been reckless and tried a 2200 4s on it, just with bursts of full throttle, and it surprisingly didn't smoke on me. In fact it only came down warm, the esc however wasn't to thrilled with my antics, as it was quite hot.

It however is only a smidge faster than the bloody wonder I made for my friend that runs http://www.hobbyking.com/hobbyking/store/__26483__NTM_Prop_Drive_28_36_1800KV_438W_USA_Warehouse_.html on a 40amp turnigy plush esc, and an APC 6x4 prop on a 4S battery. Mind you that's with me running on a 3s and him on a 4.

I would imagine to get the most speed out of that motor safely, you'd want to use a high pitch 8inch prop on a 4s setup.

Also as far as sourcing 8x8 props go, I snagged these http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LX1521&P=7. They also qualify for their parts saver shipping, so you can have them shipped for only 1.99.