Torque for Adams / Ace and other pulse actuators

[ncpiperpilot]

Hi all you single channel experts

I trying to fly a Sharkface I built with a Ace Pulse Commander and a newer Ace/Dorffler Rx. It's electric powered and I use a CL type timer for ESC/Motor control. The Rx is powered by a separate 2.4V NiMH battery. The Radio has plenty of ground range (about 270 ft, antenna down). BTW, I was originally trying to use a linear regulator off the ESC BEC but found ground range dropped to 1/3 the distance...evidently too much noise coming from the BEC through the linear regulator.

When I fly, the plane will initially roll left which I can correct but as it picks up speed it seems the actuator just doesn't have the ooomph to allow control,. I started with a Adams Std and then changed to a Stomper...same result. I am suspecting weak magnets and low torque of the probably 50 year old actuators. I attached pics of the linkage on the Sharkface and it is free and really has virtually no slop. I also posted a pic of my selection of actuators

Does anyone know the torque specs of the Ace actuators?

I do have a bunch of various actuators so I did a quickie bench test using 2 wheel collars to hold a fishing leader on the actuator wire and then hang lead fishing weights up to the point the actuator stops working properly. The wheel collars/leader weigh <5g. Unfortunatley, my scale reads in 5 g resolution, so it's not very accurate. Here are the torque results in g-cm:

Stomper #1 Coil=18.3ohm w/ 100ohm parallel / <12.5g-cm RETEST WITH SHORTER ARM LENGTH 6.5 g-cm
Twin Mag #2 (this might be a testors?) Coil=16ohm w/ 100ohm parallel / 10.5g-cm
Std #1 Coil 18.4ohm / 2 wheel collars only so <12.5g-cm RETEST WITH SHORTER ARM LENGTH 6.5 g-cm
Std #2 Coil 18.4ohm / 9 g-cm
Std #3 (Mattel) Coil 16.1ohm / 8 g-cm
Std #4 Coil 18ohm <7 g-cm RETEST WITH SHORTER ARM LENGTH 5 g-cm
Baby Twin #1 Coil 12.9ohm w/ 220ohm parallel / <7.5 g-cm RETEST WITH SHORTER ARM LENGTH 4.5 g-cm
------------
Baby Twin #2 Coil 29.3ohm
Baby #1 Coil 32ohm

The last 2 won't work reliably on 2,4V, I believe they are for 3.6V operation based on the coil resistance. I could get more accurate measurements on several by shortening the location of the wheel collars/leader....but they all just seem so weak. Many wouldn't take any weight at all added to the leader (those with a < sign)

for "fun" I measured a Hitec HS-55 and I ran out of weights at 308 g-cm (specs are 1300 g-cm). It's certainly not a powerhouse, but compared to an actuator it's a monster!

So...are my actuators weak??? I couldn't find specs anywhere.
Thanks,
Bill

[JohnH]

Since the left turn tendency increases with speed, I think your issue is more related to the air-frame than the actuator. It sounds like your problem is due to a slight warp in the wings or tail surfaces. Fix that problem and I believe you will find that the actuators will have plenty of power to maneuver the airplane.

[ncpiperpilot]

It glides straight under no power, so not unusual that it will bank to the left under power from motor torque. It probably needs a bit if right thrust but the turn is not significant enough that the rudder shouldn't correct it.

[tiptipflyer]

I had a similar problem when flying my Sharkface using a Webra magnetic actuator. It was too week and when trying to fly a turn I had to reduce the power to slow the Sharkface down and then it turned.
The Webra magnetic actuator is even weaker than the Adams actuator I use in another model (Vic Smeeds Poppet), where it is working great.
I solved the problem in the Sharkface by replacing the Webra actuator by one of Tobe´s fantastic GG actuators. No problems anymore.
You can find Tobe here at the forum and he will be glad to help you out if interested.

Frank

[Spike S]

If actuator power is marginal and more coil current fails to improve matters, let the Bernoullies work for you: try adding some aerodynamic balance to the Rudder ?

[ncpiperpilot]

Thanks Frank,
Good to know someone else with a Sharkface has seen a similar problem. One issue is I don't have a controllable throttle in the air (I can only preset power level and time with the timer). I do know Tobe and have a GG actuator setup from him for a full GG system I am putting together. One problem is the GG actuator is designed to work on 4.8-5V and the Ace system drives the Ace actuator on 2.4V. However, 5V is available from the BEC output and I could design a circuit to switch that from the Ace Rx output...it might yet be the way to go. I will reach out to Tobe as maybe he has another solution.

Thanks too Spike for the balanced surface idea...although it wouldn't look like a Sharkface if I put a Cub rudder on it Actually it would be possible to use the current outline and re-design the fin/rudder to make it more aerodynamically balanced.

I would like to see if there is any data on what a Ace actuator's torque SHOULD be.

Thanks all!
...Bill

[ozrs]

Some more info here:

viewtopic.php?p=382#p382

[Tobe]

One of the big issues concerning the Adams original actuator is that it's driven by a magnetic pulse after which it's depending on the recoil to get some force , the longer the " throws " are the less power. It's practice to have stops at about half the throw to get optimal function.
The Adams " Clone " that I designed a few years ago is based on a high rate gear ratio motor set up with a centering spring and the benefit is that the output is drive thru the full cycle assuring maximum output.
Second original Adams magnets will demagnatize over time reducing the output.
Due of the designe of the Adams the installation is of essence requiring to be as smooth as possible and what normally would feel good enough is probably to stiff!
The following are a few pictures of my Sharkface with one of my R/O bricks, this Sharkface weights in below 250 gr. with a 2s LiPo ready to fly.

[Tobe]

I'm sure the Clone with a proper switcher could work from a duty cycle instead of a ppm but probably the rate would not be the same and would need to be adjusted.
The motor will require filters to suppress interfere as the radio frequency is below about 800 MHz. I know by experience that when a cycle reverse there is a lot of interference which in the recoder is addressed by having a delay, first cycle stop slightly before reverse as the next cycle starts slight afterward.
Would it be worth for one of a kind?
The new Recoder will work with any original Adams and incorporate pwm so the voltage is adjusted in the software while working from a regular modern Rx powered with 4.8 -5.2 v.
A second feature is that the rate can be adjusted from the Tx if the second lead is connected to an Aux channel on the Rx

[ncpiperpilot]

Thanks Richard for the link, excellent info.

Tobe, love the Sharkface! I didn't realize you had an Adams clone. Will it work on 2.4V from an Ace receiver pulser output or does it need 5v and a standard servo output? I think I am going to want one of the clones

Looks like i have made at least a couple, suboptimal decisions in my implementation. I am using the full actuator throw and i could increase the force at the rudder by shortening the distance where my torque rod picks up the actuator arm.