My cooling flaps have been a huge project. I never wanted to do it, but this was the only real solution I could come up with that would solve the ground cooling problem. It has been 100’s of hours of work. I’m not adding these to the build total, it just gets embarrassing.

Version 2 for the locks is here. Test flying proved they didn’t work. The flaps still creep open despite the solenoid locks. I think when unpowered the airframe vibrations shake the little units and they open enough to unlock and then the problem is back, I had to cycle the switches to get them to close again…and a little later they would open.

I needed a better solution. Ideally the whole system would just be a simple over centre setup in the first place, not needing locks at the opening end of the flaps.

This is after many many tries and a lot of thought. Yeah a whole new set up, simple, less weight, fool proof right?

Lets try another way….

Capturing the RHS end didn’t work and all other iterations had forces that would back drive the flap door actuator, which was the original problem. So, regrettably, back to a latching solution.

I needed an overcenter catch that was strong, lite and small. Eventually one was found which you see above. Then I figured out mounting and a catch on the flap. Then it needed something to reset the latch. The microswitch at the back is to tell the circuit the catch is ‘unlocked’ before the linear actuator can move the flap.

These are close to the final design. One challenge was to build something that could use the holes I put in the cowls from the solenoid catch that didn’t work out.

A lot went into this final version and then the challenge of getting them working. Each flap was a little different and positioning needs to be millimetre perfect

Another factor was a linear actuator, small and lightweight to reset the catch. Of course I had to make a little holder to match as well.

Here’s how the flap locks.

This is the ‘unlock’

Here we are with one of the units in place. Its complex and heavy and the best I can do right now.

Here’s the whole thing in motion. A flaplocking system.

This is yet to be test flown, I still need to add a lot more heat protection as well. If you don’t see a version 4 in this blog later on, lets say it worked.