|May 09, 2010, 01:20 PM|
P-51D: Main Landing Gear Bay Doors
Main Landing Gear Bay Doors
After reading "kusunokimasahige" (I will refer to him as "KM" for obvious reasons)...After reading KM's post on his Thunder Tiger P-51 and follow-up posts on how he installed bay doors on his TT P-51, it got me to thinking!
I wanted the doors to open on their own and not rely on gravity, so using KM's actuator rod idea and some stronger torsion springs then the ones I used on the tail wheel bay doors, I set out to see what I could come up with? Along the way I discovered other ideas, one of which uses string as an actuator. I found a PDF by Phoenix Hobby Products showing a really good example of how to build Bay Doors. My only problem with these ideas was the DSR's IC system. It is designed to stop a retract if any binding is detected. So when the wheel came in contact with the rod combined with the spring tension the retract would stop as it was designed to do.
So it was back to the drawing board and figure something else out? I found a video on YouTube showing "rotccapt's" larger balsa P-51 with operating Bay Doors and after inquiring the how-to's, the term "Sequencer" arose! With this tidbit of information it set everything in motion.
Building the hinge brackets, doors and new strut skirts and all the related supports and braces wasn't that difficult, but finding a suitable servo location turned out to be somewhat comber sum! My first attempt was putting the servo in the cockpit compartment right behind the ESC, but getting the linkage to work just didn't.......work! After much apprehension, I bit the bullet and proceeded to hack a hole in the fuse. As it turned out it was the best option! Once I started the mod everything seemed to fall into place.
I tried 2 different "sequencers", the first was the RCBee. The problem with the RCBee was the 8 sec. max. delay. The DSR's take abut 10-12 sec. to fully retract and the RCBee would close the doors before the DSR's were even 50% up/closed. So it was back online to order the MicroGear from Oregon Scale Aviation. I ordered the MicroGear Sat. am and Buzz had it in my mailbox the following Tues.
As it turned out, the MicroGear is a perfect match with the P-51, as the doors close when the LG is in the down position. You can also set delays for both the doors and the retracts, although the DSR's have their own rate of decent built in.
Anyway, here is the build logs and videos! Thanks for the inspiration KM!
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