Inexpensive Electrical Flap Actuator/Sensor Idea

[MikeBFlyer]

I've got an idea for a very simple and inexpensive electric flap system and would like to gauge interest. Seems that the electric flap setup from Vans is a bit pricy and I'm not aware of a good quality but inexpensive alternative. Here's the concept:

Electric flap actuator, position indicator and all hardware
Weight: 2-3 lbs
Cost: less than $300 for everything.
Two control options and indicator options
Three position (move up, move down, stop) switch and LED bar graph position indicator
OR
Four position (retract, 10 deg, 20 deg, full down) switch with LED status/position indicator.

This type of system from Vans as far as I can tell is around $600 if you want the indicator and actuator.

Would this be of interest to anyone?

[TX7A]

Hi Mike.

RV builders are always up for a new gadget especially if it is more cost-effective. I think you need to build a prototype of your idea & have a proof of concept. There'll be interest if you can get some pics or drawings together along with some basic install instructions. Builders will need to know what's involved.

Good luck.

[MikeBFlyer]

Thanks! Good advice. Wish I had an airplane to test it on. Ill see if any RV friends want to try it.

On a side note (and probably in the wrong category) feel free to check out my LSA design I'm working on. www.jbm.aero/airplane

Mike

[kjlpdx]

square-edged tabs on your elevator rib seem they could cause problems with the skin. expected to see radius. ?

[JanRV6UK]

Another point regarding the flap actuator thing you are working on ... do not just focus on how it works .. it is equally important (maybe more important) to know how it fails .. :-)

[Pdtofly]

If you are looking for a better flap motor than what Vans sells, and is only $124, plus shipping. You can get with or without a position pot for flap position. All actuators come with built in limit switches. Vans needs the 4 in throw, but they come in different lengths. Whole thing less that $145 with shipping and works great with SkyView.

http://www.aeicomp.com/Detail.asp?Pr...2IP65+Rated%22

To make it easier, get the little mounting bracket for $7 and you are on your way.

http://www.aeicomp.com/Detail.asp?Pr...ries+Actuators

The only thing you would have to do is unscrew the outside of the pushrod, put in a lathe, drill a center hole and tap for the rod end.

These people are nice and will help you out.

Brian

[MikeBFlyer]

Thanks for all of the feedback. Those actuators are exactly what I was thinking of using, except you can get them from www.surpluscenter.com for $92. The tricky part is not the actuator or mounting. It's the control. You can rig it for a simple "move up, move down, stop" three position switch and then use the potentiometer for feedback to an instrument for position indication, but that's not what I would prefer. I would prefer to use the feed back to position the flaps at a preset angle (retract, 10 down, 20 down, full down). That way, you have a 4 position switch on the panel and you simply select the flap deflection angle desired. Pitot pressure could even be incorporated to warn you if your airspeed is too high for flap deflection. This is slightly more tricky, but doable. The idea was to offer a kit with all of this ready to install.

kjlpdx - These ribs are prototypes and should probably include features like radii on corners in the production version, you're right. I still need to make the forming dies to stamp them properly, the ones you see were just bent by hand. Thanks for the feedback!

[David Paule]

Originally Posted by MikeBFlyer

....On a side note (and probably in the wrong category) feel free to check out my LSA design I'm working on. www.jbm.aero/airplane....

You might want to investigate the results of the similar spars on the early RV-3. There's a reason why the spar caps are now machined bars.

Dave

[MikeBFlyer]

Originally Posted by David Paule

You might want to investigate the results of the similar spars on the early RV-3. There's a reason why the spar caps are now machined bars.

Dave

Thanks for the heads up.... from an engineering stand point I want to say that no two spar designs are created equal and they should all be thoroughly tested in a way which will allow the designer to be sure they will perform as expected. In my opinion, there is nothing wrong with a stacked and riveted spar as long as the design loads are correct. Lots of things go on in a stacked riveted spar assembly that are difficult to estimate, but with a large enough factor of safety a spar can be built this way which will perform completely fine for a long time. A machined spar is simply easier to design such that it's behavior is more predictable and so you can get a very light and reliable spar. Machining it is a bit more difficult, but you make a good point. There is a reason they changed. I think in Van's case it was probably that the cost of having the spars machined was worth the warm fuzzy of being able to more accurately calculate the allowable loads and the fatigue properties.

For my structural test prototype wings which will not ever fly, I'm planning to do a stacked spar and then depending on the test results, both static and cyclical tests, I will decide how to proceed with the flying prototype. The idea with this airplane is to keep the cost very very low, so that is a major factor.

[JonJay]

Originally Posted by David Paule

You might want to investigate the results of the similar spars on the early RV-3. There's a reason why the spar caps are now machined bars.

Dave

All of the 4's and 6's are built the same way as the 3. Machined spars took some of the builder variance out of the equation but many will argue that the original design to be actually stronger.