RE: Who wants good Retracts?
Hi Mike:
No - I am not in the market for retracts, but for you I have some food for thought. Like you, only it's been fifteen years, I got fed up with the retracts on the market, and decided to design my own. These were for 1/4 and 1/3 scale planes.
Like you, I started making mine like all the others - and when I was done, they were no better than the others. Then I took a completely different approach. All you want to do is to rotate a gear in some fashion about ninety degrees. One of the big problems with the gears on the market, was that the hold down platform wasn 't large enough to withstand the loads exerted on them by the longer landing gear. Thus, on any landing other than a very smooth one, the gear was likely to rip out, and most of them did.
So I came up with a completely new idea. Why not build the gear into the wing from the very beginning, on an aluminum tube that rotated between the front and rear spars. Wooden bearings securely fastened to the spars held the tube in place. Inside the tube, I machined a wooden block that was press fitted in the spot where the gear was to be located. The gear was held in place be two locking screws. If a gear bent for some reason, just pull it out, and insert a new one. It can be any wire size that you want it to be - no restrictions.
Now all that is left to do is to figure out how to rotate the aluminum tube. This was quite a challenge. First off, all the gears that I had used were pneumatic. I decided mine had to be electric. I went to K-Mart and found some real cheap battery operated screwdrivers, and these became the power source - running off 4.8 volt nicads. I devised an ingenious method of rotating the tube by turning a screw through a moveable block tied to the tube by two fixed posts. The moveable block had to stay in a fixed plane relative to the screw, and it changed planes in relation to the tube as the tube was rotated. The amount of rotation was controlled by two limit switches, that were completely variable. For instance, if your plane had 5 degrees of dihedral, and you therefore wanted your gear to only rotate 85 degrees, all you needed to do is to set the switches that way.
We installed these gears on some racing AT-6's with G-62's, and they worked flawless. The electric provided about a seven second cycle from down to up, and vice versa. We built the gear tube right into the fiberglass wing section, and it was stronger than - you know what.
One of the biggest advantages of this design is the fact that the gear is always locked, in any position, either up, down, or half-way. You needn't worry about a gear collapsing when a side load was applied.
The planes that these gears were in are long gone - Have no idea where they ended up. Also have no photos of the actual installation, but I still have the prototype box that I used to prove that the design would work. Consequently, I dug it out of the "old stuff", and took three photos for you to look at. I didn't have a gear and wheel to install, so I just stuck a piece of brass tube in where the gear would go.
Photo one is the gear in the retract position. Photo two is the gear as it moves from the retract position to the down position. Photo three shows the gear in the down position.
I only show you all this to get you to imagine other ways of doing the job. I agree that the whole industry needs better retracts, but it isn't going to happen if we continue to copy the designs that are already out there. So, put on your thinking cap; start with a clean sheet of paper; and see what you can come up with.
Can you figure out a better way to rotate the tube? That was my biggest hurdle. The rest was easy.