FlyingGiants Forums - View Single Post - Powersystem Comp 12

Dumorian · 05-05-2009, 02:27 PM

I have a new Powersystem Comp 12. I'm running a 6014 receiver, two 7.4v 1400mah Lipos. I have the ignition cutoff unit separated and on another battery. The model is a Dynaflight Decatlon, 36cc which weighs in a around 20 pounds when filled with gas. It has a 89" wingspan.

Flight controls include 2 servos on ailerons, 2 servos on flaps, 2 servos on elevators, one servo on rudder, one servo on tug release, one servo on bomb bay and one servo on throttle.

On the first day out, the power was on to all systems for maybe 4 or 5 hours. The model was likely either in the air or experiencing programming on the ground for maybe 1 hour. I ran the engine for maybe another half hour. This all to let you know that after this time, the flight batteries took between 400 and 450mah when charged. So, I think I have a pretty darned efficient setup with no extra drain due to a binding servo or something.

Yesterday, during the second flight, I thought I'd try a loop. Instead it looked more like a snap roll. So, I tried it again and same results? Odd.....

Back on the ground, we noticed that it didn't take much force to override the elevator servos. These were Hitec 635s which are around 80 ounce. Surprised by this, I changed them out for a pair of 5645s last night, which have about double the torque. I seem to get about the same results in overriding the elevators with my hand? I'm thinking I should feel like something is about to break before being able to do this, but in my unscientific by hand testing... it doesn't feel like something is anywhere near a breaking force.

OK, so, I popped the cover off the bottom to watch the whole system. I made custom CF tube control rods and nothing is flexing. The servo arms are simply being overridden.

Of note, first I am on the default voltage with the Powersystem, but I have not checked the output. First, I have 12" heavy duty Hitec extensions on these servos. When I hit this override point, it's like the servo just all but totally gives up... so it goes from pretty strong to almost no power at all, then when I ease up on my force, it regains it's power.

I'm wondering if I'm missing something? I know the system has a short protection function and wondering if somehow it's reducing power to these servos at a point below where it should, seeing my load as a short? Also, I didn't ask the first simple question of whether or not you consider the (2) 7.2v 1400 mah 10C batteries to be enough power for the system? It seems I should be able to put out nearly 30A with these. 3 or 4 should be plenty when testing only just one elevator servo with everything else being at the nuetral point.

Anyway, if I've missed something or you have a suggestion, please let me know. I'm hoping to fly this model at Joe Nall next week.

05-05-2009, 02:27 PM	#1 (permalink)
Dumorian ...all in my brain Join Date: Sep 2008 Location: Goshen, VA Posts: 135 Awards Showcase Total Awards: 1	Powersystem Comp 12 - weak servos I have a new Powersystem Comp 12. I'm running a 6014 receiver, two 7.4v 1400mah Lipos. I have the ignition cutoff unit separated and on another battery. The model is a Dynaflight Decatlon, 36cc which weighs in a around 20 pounds when filled with gas. It has a 89" wingspan. Flight controls include 2 servos on ailerons, 2 servos on flaps, 2 servos on elevators, one servo on rudder, one servo on tug release, one servo on bomb bay and one servo on throttle. On the first day out, the power was on to all systems for maybe 4 or 5 hours. The model was likely either in the air or experiencing programming on the ground for maybe 1 hour. I ran the engine for maybe another half hour. This all to let you know that after this time, the flight batteries took between 400 and 450mah when charged. So, I think I have a pretty darned efficient setup with no extra drain due to a binding servo or something. Yesterday, during the second flight, I thought I'd try a loop. Instead it looked more like a snap roll. So, I tried it again and same results? Odd..... Back on the ground, we noticed that it didn't take much force to override the elevator servos. These were Hitec 635s which are around 80 ounce. Surprised by this, I changed them out for a pair of 5645s last night, which have about double the torque. I seem to get about the same results in overriding the elevators with my hand? I'm thinking I should feel like something is about to break before being able to do this, but in my unscientific by hand testing... it doesn't feel like something is anywhere near a breaking force. OK, so, I popped the cover off the bottom to watch the whole system. I made custom CF tube control rods and nothing is flexing. The servo arms are simply being overridden. Of note, first I am on the default voltage with the Powersystem, but I have not checked the output. First, I have 12" heavy duty Hitec extensions on these servos. When I hit this override point, it's like the servo just all but totally gives up... so it goes from pretty strong to almost no power at all, then when I ease up on my force, it regains it's power. I'm wondering if I'm missing something? I know the system has a short protection function and wondering if somehow it's reducing power to these servos at a point below where it should, seeing my load as a short? Also, I didn't ask the first simple question of whether or not you consider the (2) 7.2v 1400 mah 10C batteries to be enough power for the system? It seems I should be able to put out nearly 30A with these. 3 or 4 should be plenty when testing only just one elevator servo with everything else being at the nuetral point. Anyway, if I've missed something or you have a suggestion, please let me know. I'm hoping to fly this model at Joe Nall next week.