FMS V7.5 P-51 BBD: The 1-Piece Wing!
My BBD 1-Piece Wing Mod!
I'm going to illustrate how I go about making the wings a 1-piece unit.
The first thing I always do is eliminate those 3mm philips head anchor screws. On the BBD I chose to use (2) 6-32 X 2 1/2" hex head cap screws in the rear mounts, and (2) 6-32 X 2" in the front mounts. I had no problem tapping the rear mounts as they consist of a 3mm nut encased in a plastic anchor assembly embedded in the fuse. The front mounts, on the other hand, proved to be a bit of problem! They consisted of (2) 3mm T-nuts embedded in some kind of high density foam, not plastic....foam? Needless to say, when the 6-32 tap hit those T-nuts there wasn't much securing them in place so they let go. I ended up having to cut the whole anchor assembly out. I'm kinda happy I did, as I'm not sure how long that configuration would hold up?
My solution was a piece of 9/16" X 1/2" X 85mm UHMW plastic. I drilled and tapped the two 6-32 holes 75mm apart. I then drilled several holes in the plastic anchor for the glue to penetrate and bond to. After securing the plastic mount with epoxy, letting it set for 30 min., I dripped several drops of water in the seams and applied a generous amount of GG securing the whole repair with tape to help corral the GG expansion. Once everything was dry I applied a coat of Krylon Bright Silver and I was good to go!
Before I ever glue the two wing halves together, I like to make sure I have all the mods done that I intend to do. In the case of the BBD I had several to complete.
1. The PZ-312 to PZ-514 conversion.
2. Re-wired the Nav lights to eliminate the resistor.
3. Build a set of landing light housings for the struts, and run their leads thru the wings.
4. Removed those plastic pylon mounts and built my own pylons.
5. Paint and mount all the control horns, and hook up the linkages.
6. Re-hinge the control surfaces.
7. Finally, I mark all my leads, port and starboard, so to not add any confusion when it comes time to wire up my multi-connector.
Once I had everything done, and I was ready to glue the two wing halves together. I poked numerous holes in the facing of both wings so when the GG started to expand, it would fill them and make for a more solid anchoring. I then slid the V-shaped aluminum spar in along with a Carbon Fiber spar I chose to replace the fiberglass one that comes with the plane. To insure that the wings would be lined up with the four mounting holes, I first put a strip of masking tape on the inside seam of the wings to help contain the GG, and then loosely mounted the wings on the fuse with the four 6-32 bolts leaving just enough gap to get a combination of water and GG down inside. Once the glue was applied I tightened the bolts down, which helped pull the two wing halves together, taped up the seam and then sat back and watched the glue dry. Actually I had other things to do so I let it set for a couple of hours.
Satisfied that both halves were now one, I removed the wings from the fuse, removed the masking tape, and was pleased with the results. The wings have been attached several times now, and I have had no problems. Yeah!
The second step to a 1-Piece wing design is the wiring. There's not much sense in doing so if you're going to spend time at the field plugging each lead in to the Rx. I have been making my own multi-pin connectors for some time now. FMS has followed suit, and have now made available their own version of a multi-connector which comes in 2 parts, part 1 & part 2. Using theirs or making your own, either way, it makes mantling or dismantling the plane for transport a snap!
The Drop Tank / Bomb Pylons!
I replaced the plastic drop tank pylon anchors mounted in the wings so I could use my own handmade pylons. That way I can mount either my own Drop Tanks or my 500lb. bombs.
The .50 cal Guns!
I just had to re-configure these .50 cal guns. Although they're a better design then those gawdy ones on the earlier versions, they still weren't scale, there's no off-set stagger.
First I took my saw to 'em and trimmed 'em back to create some stagger. Then I painted the housings surrounding the nozzles flat black. I wanted to add something to resemble gun barrels so I took a piece of K&S 3/16" X .049od. aluminum tubing and turned it down to 0.157od on the lathe so they would slide in the nozzles. I then added a bit of relief in each gun with a countersink (just cause it looked better), cut each piece to length and CA them in place.
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Joined May 2012
Thank you for showing us how to do this stuff.
My BBD is about six weeks old, and I'm interested in removing the wing for transport.
Perhaps I just haven't looked in the right place, but I can't tell how you make up the multi-connector. I was going to use a 3x8 header for one side and CA together the servo plugs for the other side. I'm not interested in the FMS connector because I'd like to do more lighting as you've done.