Torque for Adams / Ace and other pulse actuators

[ncpiperpilot]

Hi Tobe,
Oops, you answered my question while i was typing my reply. Although I really wanted to use the original Ace radio, if the actuators are weak, I may just swap to using a 2.4GHz radio i have already made. It has Phil's 1+1 encoder and I can eliminate the Motor timer and use a much lighter Rx.

I'll email you about setting me up with a clone or 2.

Thanks,
Bill

[ncpiperpilot]

After chatting with Tobe, he convinced me (rightly so) to use his Clone Actuator and move to 2.4GHz with the Sharkface. I'm not completely giving up on using the ACE Radio with the Adams Actuator though. The Sharkface is a rather small plane even though it was designed for an 049,,,its pretty fast and will put a fair load on the rudder. I am building a DMECO Kitten designed by Hal DeBolt from 1953 (also designed for a 049) for RO and I will try the Ace radio in there. It will be a much slower airplane...check out the pics of the wing size (34" 220 sq in) vs the Sharkface. Oh, BTW, I updated the data on the Actuator torques by remeasuring some and reposted in the first post.

[ncpiperpilot]

I updated sharky with one of Tobe's Adams clones and a Lemon Rx. Here it is, ready to go.

The old weight was 9.2 oz for just the fuse with everything installed. The new weight is 6.2 oz. For a 3 oz / 90g savings! Sharky with the wing is 225g, flight weight with a 500mAh 2S Lipo is 260g. Pretty close to Tobe's.

What I eliminated was the "touch and go" ESC timer/driver, the Ace Rx, a Stomper actuator and a 2 cell Nimh battery.

Bill

[ncpiperpilot]

While Sharky is done, I'm still working towards more powerful actuators that i can use directly with my Ace Rx's.

Digging thru my boxes, I found a vintage Southwestern actuator. While it seems heavier, it weighs the same as an Adams Stomper 1.8 oz). The specs on the H bridge transistors on the Ace RO Rx is actually 500mA. With both coils in parallel, running at 2.4V driven from an Ace RO Rx torque is about 7.5 g-cm. That's about inline with my Adams Actuators. Now in all fairness, this actuator is spec'd to operate from 3-9V. So.... if I was running with a higher voltage I could likely get much better torque. Can't easily do that with an Ace Rx.

I also experimented with driving an old 4 wire Kraft servo motor directly from the Ace...it won't reverse fast enough to work. I used it because the motors were designed to operate on 2.4V. I assumed it was either the motor momentum or not properly dissipating the coil energy fast enough. Looking at the Ace schematic, there really isn't what I would consider proper circuitry to clip or dissipate the coil current on a switch. Typically catch diodes to the supply and ground are implemented or back to back zeners (or a transorb) across the motor.

I put an order in for a couple Pololu DRV8838 drivers. I'll pick off a drive signal from the Ace Rx and I can use a higher supply voltage on the actuator just to see how much torque I can get. I also can play with proper energy dissipation on the servo motor to see if i can get it to reverse faster.



..Bill

Bill, I have put your video on my account on YouTube however it's unlisted and I have also resized your Sharkie pic. (Trying to save as much space as possible on the server...hope you don't mind
Cheers, Tobe