N1EDM

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Take pictures & vids!!

Mustang Fever

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Here's some more thoughts on strengthening the main gear retract mount area:

1. I added laminated strips of 1/8 x 1/4 spruce to the front and rear edges of the plywood mounts. This after seeing how little material is left around the bolt and blind nut holes once the blinds are installed, and how the plywood is weakened by the "spears" on the nuts. Next time, no blind nuts.

2. 1/4 x 1/2 aluminum angle is easily fitted around the top and edges of the mounting wood, glued with Elmer's poly glue and clamped in place by 6-32 self locking nuts. As the nuts will have to be reinstalled after sheeting the wing and replanting the gear, I'm planning on a hatch above the gear assembly. This will also allow access to the side mounted air fitting on the retracts.
From an earlier post, one can see the 1/4" birch ply "cage" for the landing gear mounts.

3. I put 1/16 ply shear webs on both sides of the main spars, from W2 to W6. Holes are drilled through the centers to allow for air tube routing.

I'm quite convinced that this is the minimum reinforcement necessary if one is using oleo struts that mount directly into the retract blocks, as opposed to bendable pins, or wire struts. With nothing to give and absorb bending loads, the mount area must be really bulletproof, as Topflite alludes to in the instructions.

Mustang Fever

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What you see represented here, timewise, is 90% cutting/pasting/fitting (for the retracts), and 10% assembly time. I really like this kit. Topflite did a great job in the design, and everything fits together really nicely.

I B BUCK

Hey guys i picked a BCMA spe 26 for a P-47 . I'm going to put one in my P-51 when I get to that point.
Here is a clip of the break in. can't wait to fly with it.http://www.rcuvideos.com/item/QVZYTB6MW3TJXVFM

Mustang Fever

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Buck:

Is that a 26cc gas?

I keep thinking about that. Don't know if I want to try it or not.

bigtim

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I B BUCK,I was thinking along those lines myself when I fitted a BCMA26 to my TF P-47 the actual engine fit well and the weight was perfect the only problem for me was when it came time to fit the cowl,I also had a custom muffler made for it from Brillelli engines,there was just so much engine that was going to be hanging outside of the cowl,and the electronic spacing required(keeping the reciever and servos from the elec.ign.) that it became more trouble than it was worth and I ended up selling it,and putting a OS 120fs in the nose.
I think the 26 might be a bit big for the mustang,I have a TF Spitfire and the nose is pretty lean,as well as a Mustang in the box to build,I have been following the KMP FW 190 thread and the author is installing a BCMA26 in that if his works out well I would consider installing one in that airframe there's alot more room in the fuse and cowl..
some shots of my fitting the 26 in my JUG its close but when its time for the cover up theres alot of material to remove to get the cowl to fit.
the OS 120 is a nice match

I B BUCK

Yes it is Bob. The clip doesn't do it justice. It sounds awsome . I can put an 18" prop on it.

Big tim I was looking at a pitts style muffler to go in the stang with the engine. Your right it will be tight. I still have to build the fuse
then I'll test fit the one I have to see how everything looks

Mustang Fever

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I'm probably gonna chicken out and stick with the inverted Magnum 91. I'm hoping the Slimline inverted, wraparound Pitts muffler will fit in there with it. If the Magnum doesn't work out, an OS 91FX is a drop in replacement. I'd love to E power this thing, with an Astro 120 turning an 18 or 20" prop, but the math says that would cost an extra 23 ounces, as well as about $900. I think she'll be heavy enough, and I'm already broke enough. The wing prior to sheeting weighed 43 oz, 20 of which is landing gear, wheels, and plumbing. If she comes out even a little bit nose heavy, I'm going to have to chuck the pretty Robart wheels and go with good old Dave.

Finally reached the point of "Sheet the Wing", page 21. This was after seeing, way back on page 18, "when you are totally ready to join the wings, trim off all the jig tabs except those on W-2 and W-12." No way Jose. I've built my share of warped wings, and this aint gonna be one of them. I left all the tabs on, and as you can see, one panel is totally pinned down to the board and the other is hanging in the air during the sheeting process.

I'm really tickled with the way the landing gear turned out. With the gear extended and the wing propped up in back so it sits on the wheels, there is only 1/16" difference in the height of the wingtips above the board and the axles are way out in front of the CG. Still don't know about inner doors, but outers will work ok. The only way I can get inner doors is to cheat a little- maybe some 1/4" or even 3/8" balsa added to the wheel well area sheeting that I can taper into the wing. More on that later.

saramos

Hi Bob

I just wanted to give you a Thanks! The work you've done has really been a big fast forward for me as I plan out the retracts for my build. I just finished up my mockup and it looks like the only change I'll have to make from my original plan is to subsitute the 4" wheels with 3 3/4" wheels. It's not too bad a change. At 1/7 scale, the scale size wheel is just a smigen under 3 7/8" so the 3 3/4 is actually closer to scale (barely). But the 4" wheels look better on the struts I'm using. As for added thickness, Since I'm covering my wings with FliteSkin instead of glassed balsa sheets, I had to add 1/16" cap strips to the ribs and spars so the skin will properly meet the leading edge. As a result, I gained 1/8" of space. I am tempted to go with 3/32" capstrips for just a bit more space.

I don't have a wing up on two main gears, but I've got one gear on a stub ...

Scott

Mustang Fever

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Lookin' good, Scott

Keep at it.

Mustang Fever

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I read about problems with the flaps warping on another build thread, so I made a tapered balsa support to go under the TE of the flap during sheeting.

Note high tech weight system used while glue cures.

I'm now thinking about trimming it like "Speed Ball Alice", that competed at Reno last year.

Mustang Fever

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The sheeting on the lower, right hand wing panel is almost finished.

I decided to take a shot at gear doors, and started by making a one piece, 3/32" balsa template of both doors. I used the plywood outer door supplied in the kit, plus a drawing of the inner that someone posted on another thread. When I printed it out, it exactly matched the outer door.

I wet the outside surface of the template real good, so it would warp and follow the contour of the wing, more or less.

As you can see, I'll have to glue some 3/8" balsa sticks around the door opening on the aft edge toward the center, and on the centerline edge near the rear. Should be able to blend everything in real nice. Once this side is completely sheeted, I'll do the other panel, then start hinging, fitting, and linkaging the gear doors. I plan to use a single retract servo mounted on the upper wing surface to haul back and forth on two cables (from throttle cable kits) to actuate the inner doors.

If any of you guys see me at a scale meet, feel free to rat me out.

hornetcv64

Well, she went on her mayden voyage yesterday. Needed a lot of nose down on the stick to keep her on the ground but flew very nice. Very touchy on the sticks for the elevator and alomost lost it at one point. I could not get over how sensitve it was to stick movement. After the first flight we reset the throws on the elev. and it flew like a dream. To finally get it into the air and fly like that was unbelievable. We did some high speed machine gun runs and it was hummin. I could not have been more proud of it. Especially being my first build. On the 3rd landing we did hit a hole and broke the other main this time. I guess I have not beefed it up like the other side but will fix that this week and have it flying by next weekend. If I get some pitures at the field I will get them posted. All ready looking for my next build! LOL

Mustang1964

Hornetcv64:
Sounds like it was a great time. How do you have your throws set? My fear is that the sticks will be over sensitive for me as well and I will end up putting it down hard.
Please let us know how the next flight goes.
Mustang1964

hornetcv64

Mustang64 I will check the throws this week on everything and let you know where they are set. The ailerons were near perfect with the rudder. Can't wait for next weekend!!!!!

Mustang Fever

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Finally got the bottom of the left wing panel sheeted, so started work on the LG doors.

I'm cheating in two ways to get the doors to fit properly: 1) raised the center and aft edges of the wheel well opening by about 3/32, using balsa, tapered into the wing shape.
2.) My door is of 3/32 balsa, held in place and thoroughly wet on the outside so it will mold a little to the wing curvature. When it's dry, I'll use some light fiberglass and 30 minute epoxy (thinned) to cover the outside. Then, after removing it and extending the gear, I'll glass it on the inside. This will result in very light, very thin doors that will fit and not be too flexible. I hope.

I made two additional "W1A" ribs, shortened to fit between the main spar assembly and the back of the LE joiner. These will serve as mounts for the inner door hinges.

manolomartin

HI EVERYONE,

LOOK WHAT I`VE FOUND... NOT FOR A SCALE CONTEST BUT IT WILL SHURELY PUT MORE THAN ONE INTO WORK TO IMPROVE THE IDEA...

MANOLO MARTIN
MEXICO

Riddle4U

Mustang Fever; excellent craftsmanship from looking at your photo. Thanks for that. I hesitate to recommend differently since you are well into your chosen method. My method will be to Monokote the entire gear area, spray it with PVA mold release, and then lay-up a little fiberglass over the entire gear area. After that you cut out the openings, transfer pencil lines through the fiberglass(you can see your cut out through the glass), cut out your doors with the scroll saw, and then you are flush with the whole deal. I will try to carve and sand a better profile than most on the inner surfaces of the gear doors. This is where I see most fail. The expensive Aerotech Mustang is poor in this area as well, but it provides an oportunity for a good eye to improve. LOOK at photos! Good luck! As an edit, I complement you on the outline of your inner doors, and I notice that it looks like you brought the innermost ribs closer together than the plan (as I did). I should have narrowed that structure even more, like you did. By the way, I used my enlarged inner wheel well to place the wing mounting bolts within the wheel well. I think this is maybe too annal for this model but it is all practice..right?

Mustang Fever

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Thanks, Riddle.

If I ever do another one, I'll use your method. I got in trouble with the 4" wheels on this one, and angling the lower ends of the struts forward didn't help any.

Mustang Fever

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Three days and here's all I have to show for it: sometimes I think I'm not building an airplane, just a flying landing gear mounting system, OR "How long did it take to build it?" Reply: "A year for the landing gear, and a month for the rest of it."

Had to do some shimming on both retract assemblies to get the wheels a little deeper into the wells, and taking out some toe in (I had way too much) helped get the trailing edges of the tires into the wells better. Here it is, the left door is hinged, and only gravity is holding it closed. I'll need to add a little "cheater" balsa around the front of the opening. Otherwise, it looks like this might work OK.

There appears to be enuff room between the door and the tire to add the inner panel like the real one, I'll just have to keep it very skinny. If all this works, I guess I'll have to go ahead and build a cockpit for it, along with some other detailing.

saramos

That's looking pretty good there. It gives me a lot of encouragement. I think your idea of a little balsa buildup on the front will be just the trick. I think I'll use a little thicker cap strips from the gear mount inward and gain the extra space that way.

Scott

Mustang Fever

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Scott:

I thought about putting capstrips on the ribs before sheeting, and somewhere that idea got lost.

saramos

I'll be covering my wing with .010" G10 (Flite Skin) instead of balsa and glass, and I need to make up the difference in thickness with capstrips anyway. I was originally planning on using 1/16" thick capstrips, but will probably use 1/16" on the outer portion of the wing, and 3/32" around the strut area and maybe even 1/8" over the wheel well. I'd feel better with a little more room than what I have in the mockup.

I picked up some Hitec wing servos at the convention over the weekend. I may look into using one buried inside the tail for the rudder with a rotory drive setup to eliminate all exposed linkages.

Scott

Mustang Fever

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Scott:

Now, that wing servo in the fin sounds like a good idea. I bought two of the same ones for the ailerons, as I don't like the idea of complex linkages that are so buried one cannot work on them without cutting the airplane apart. One of those should be plenty for the rudder, as you'll obviously have a separate tail wheel steering servo.

Flying Beagle

Bob
your doors are looking really great, I have gotten all caught up in another build and had to hang my Mustang wing up for a while

totally agree with your comment: "just a flying landing gear mounting system"

Beagle