Stronger alternative to Beckman Concealed actuators?

[rparigoris]

I need a stronger alternative to Beckman concealed actuators.

I am using 1 Beckman concealed actuator on each side of my 5 pound Slope Slayer to articulate the NASA Lead Edge droop.

Articulating the Lead Edge is well worth the effort. It slows the model nice, and reduces stall speed.

The problem is with the Lead Edge drooped full, it tends to break the control rods in the device on landings.

I purchased these from hobby lobby, and are far superior to the similar all plastic hidden control horns.

There is a fair amount of load if the grass is not mowed real short.

Anyway it seems that Beckman went to the trouble of selecting some not too strong steel for the control rods, and made the hinge pin hole very large, which causes this to be a real weak link. My feelings are they did this on purpose to be the weak link and perhaps not break the control surface? Either that or they had a fairly large amount of old orange juce cans and hangars laying they wanted to get rid of.

Anyone know of a stronger alternative?

If can't find stronger, alternative is to machine some rods out of stronger material, and or install 2 or more per side set up in parallel.

The first option is i will make up some mild steel replacements and try and retract LE Droop full up prior to touchdown. This way the droop is against a stop and there is no load on the device.

Any ideas?

Ron Parigoris

[RMihara]

Although I am unfamiliar with the Beckman actuators I think the KISS method here (retract the droop prior to touchdown) is your best bet. Reinforcing the control rods would only place the high stress onto another part...would you want to re-build a control surface after it breaks?

The only other thing I could think of is to have some sort of skid plate on the leading edge to prevent it from 'digging' into the ground upon landing.

Regards,
Roger

[bobthenuke]

Regarding these actuators, is there any mechanical advantage? For example, If I require 10 ounce inches of torque to move a surface, will I require a servo with less torque or more? Also, how much movement of the control rod is there per degree of movement. Again, for example if I move the rod 1/2 inch will the deflection be equal to 30º? I'm just using round numbers, I have no information about these actuators other than what I've read in this thread.

Thanks!

...bob

[Purdue Aero Man]

Can you give us some pics?

[Ollie]

http://www.irfmachineworks.com/rds.
http://www.servocity.com/html/servo_shaft_adaptors.html
http://www.genie.rchomepage.com/
Download File 06, RDS

[bobthenuke]

Olllie,

Thanks for that information. The IRF system appears to be different than the Beckman Actuators, but I now have an idea that will allow me to eliminate the Beckmans.

...bob