THRL-CKER

I just bought a Great Planes Rifle and am looking for the right motor set up for it any suggestions.

Jim

David Jackson

My Feedback: (15)

I got the Ammo 24-33-4040kv in mine. Not sure what kind of performance to expect, but since the airframe is smaller than my Evader, I will be satisfied to achieve a speed of 110mph. However, I would also be interested in the motor/battery combination others are using in the Rifle, and the speed performance.[8D]

krproton

Hi guys.

I have a couple of my own Rifles I’ve flown at different Watts outputs. The Rifle is rated for up to 300 Watts which should get you in the 100mph range, but I know it can withstand 350W if you are also under the recommended max. weight (19.2 oz) (but you may void your warranty if flying over 300W). Much over that and you should consider reinforcing the wing and/or executing your turnarounds with a little care (throttling back and/or not pulling full elevator immediately) so as not to overstress the wing.

Here are my descriptions on how the Rifle flies at these Watts:

250W (28-35-2700 Ammo): 100 - 110mph, good speed, but at this power keep the plane normally light—no modifications are required, just stay away from oversize servos, batteries and ESC. A good toss with the wings level is also important. Headwind helps—DO NOT launch with the wind!

300W (24-33-3180 Ammo, ARC 28-37-2.5): A very nice setup. Easily 120+mph speed. Launch conditions and technique a little less critical, but still use headwinds if present.

350W (ARC 28-37-2, 1500mAh 25C battery): Now we're stepping it up. Not for beginners. Don't try this unless you've already flown with 300W or are a darn good pilot to begin with. Less thinking, more reacting (which means, in order to react without thinking you better already know what you're doing because there's not enough time to think!). This is when being skilled and confident enough to turn hard and fast helps to keep the plane closer. Otherwise, the Rifle can get away. At this power (and beyond), you still want a nice toss, but launches will be a non-event because the plane gains speed and altitude immediately.

Here’s a nice video flying my Rifle with the 350W setup:
http://www.youtube.com/watch?v=gOxi61oxfnM

450W (ARC 28-37-2, 1800mAh - 2200mah 25/30C battery): Now we're getting really serious – only for those already experienced with this type of plane. 140 - 150mph. To accommodate larger batteries you may have to grind out the bottom of the plywood front former and reinforce the bottom of the fuselage with Dave Brown carbon fiber tape http://www3.towerhobbies.com/cgi-bin...&I=LXB964&P=ML . Heavier batteries put more stress on the wing, so now you should fly a little larger, more carefully, but you can still fly with the throttle "firewalled." Without any tail weight, your C.G. will be ahead of the recommended range (about 3/16" behind the wing TE), but the Rifle doesn't seem to care. But you may want to increase your up elevator throw by about 1/32" to 1/16" (but use high rates only for landing).

Here’s a link to a 480W flight:
http://www.youtube.com/watch?v=YAOzm...eature=related

600W (MEGA 16/15/2, Hyperion 1800 35C battery): Now you're off the grid. My Rifle with this setup was "dopplered" at around 165mph – and that was on the first/second flight of brand new batteries. The most important thing is to remember to turn it in time, otherwise you'll lose sight of it. Also, to keep your Rifle close, rather than doing banked turns, perform a “humpty bump� with a pull over the top: Pull to a vertical up line, half roll, then pull over the top making a gigantic ¼ loop returning to level flight—this all happens within seconds! It keeps your turnarounds and all your passes on the same line.

600W video:
http://www.youtube.com/watch?v=33lz1NbFITk

You can also have a nice time with a 2S setup. 2S is slower, but still fast enough to definitely get a rush and lighter making it a little more maneuverable so you can "flick" it around faster until you get your timing down. You need a motor with around 5000kV for a 2S setup and around a 1800mAh battery to keep it light.

JohnRC

I'm going to order a GP Rifle. It seems to me that the AMMO 24-33-4040 (KV 4040) would bring this plane to higher speeds than the ARC 28-37-2 since the KV is 3750.
Running the same APC prop 4.75 X 4.75.
Please let me know if I'm wrong about this.

Thanks
John

David Jackson

My Feedback: (15)

I installed the Ammo 24-33 -4040KV in my first Rifle assuming that I could get higher speed with that setup. I used the APC 4.75x4.75 prop with the 3s 1600 mah 30c battery. Unfortunately, smoked the motor on the fourth flight. Had a couple of Ammo 24-45-3790 KV that I used in my Evaders, so installed one in the Rifle. Performance is not bad. If you don't presently have the motor for the plane and you are wanting max speed from your set up, read through KrProton's posts for suggestions on powerplants. IMO the info he has provided does seem to eliminate a lot of the trial and error when selecting a motor for the Rifle.

bigbri

My Feedback: (287)

KrProton i am going with the ARC 28-37-2 motor and 3 cell 1600 mah batts. and a 35 amp speed controller. what props do you think i should start with?

Best
brian

krproton

Sorry guys. Haven't been over here in a long time. Looks like the thread is dead, but I'll answer anyway...

Yes, the 4040 has a higher kV than the recommended 3180, but the 3180 is already being pushed to its limit (over the limit?) on 3S with a 4.75 x 4.75. Even with that motor you can't fly full-throttle the whole flight or you will cook the motor eventually. If you jump to a 4040 and use the same prop and battery, you're DEFINITELY going to smoke the motor. What you need to do is run it for a second or two with a Watt meter and read the current its drawing and compare that to what's the limit for the motor. I've found that for most motor and prop combinations one woud run in a plane like this you can shave about 30% from the static current to predict what you will get in flight. In the case of the 3180 it draws about 28A staitc which, less 30% (to find out what it's actually going to draw in-flight) = about 20A (in flight). But the 3180 is rated for 17A constant current/20A bursts, so as you can see she's right at the edge already.

Now, if you step up to a higher kV (4040 as suggested) it's going to draw even MORE current with the same prop and battery because the motor is going to TRY to spin the prop faster, thus working harder (and drawing more current).

Actually though, this motor makes a WONDERFUL 2S setup. But you need to step up to a 5.0 x 5.0 prop. With this prop and a 2S, 1800mAh 25C I get 30A static @ 19,700rpm off the initial battery charge. History tells me current drops about 30% in flight putting it at about 21A in the air (in-flight Eagle Tree data proves I am at about 21A or less in-flight). The motor is rated for 18A constant current, 28A surge.

You'll need to add about 1/4 oz. of led in the nose to get it to balance though.

Tim

krproton

Hi David.

You beat me to the punch on this one. I ran the same motor (24-45-3790) the other day, but I used a 4.1 x 4.1 prop which puts it right at the top of its suggested current draw. I think you're overpropping it with that 4.75 x 4.75 and I doubt she'll last very long. Anyway, with the 3790 and 4.1 x 4.1 it flies great. The motor is a little heavier than most good 28mm motors and I don't like the flat spot on the motor shaft, but it does work well none-the-less.

Captain Terrific

My Feedback: (2)

Tim, Ijust ordered one of these with the stock set up. If I'm pushing the 3180 with a 4.75 X 4.75 should I drop down some. Say to a4.7 X 4.2?

Dave