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Old Aug 13, 2008, 06:47 AM
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USA, MA, Longmeadow
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Builder's Oops...

JimT, the fuselage does seem very robust and sturdy. I think it will definitely handle some "less than perfect" landings. On the tailfeathers, after I built them I was a little bit concerned about the torsional strength of the elevator "joiner" area. I expressed my concern to Brian, and he agreed it might be a problem. At his suggestion I've strengthened the area by laminating a piece of 1/64" liteplay to the area. Brian has told me that he is going to look at a design change for this area. Picture attached. The piece of lite ply has removed any concerns I had about the elevator halves twisting under load.

And my oops... I got an email from Brian yesterday, after I posted up the picture of the completed fuselage. It turns out that I should have crossed the guidetubes to the rudder, rather than running it straight back. With the geometry the way I built it, the nosewheel is going to turn in the wrong direction from the rudder. I planned on using it primarily as a taildragger anyway, so it isn't much of an issue for me. This problem will be solved by noting the correct geometry in the instructions, so it shouldn't be an issue for any future builders.

Mark
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Old Aug 13, 2008, 08:15 AM
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glewis's Avatar
USA, FL, Tampa
Joined Jul 2002
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That center section does look a bit weak. I have broken similar designs by bumping the elevator while putting the model in the car .Think I'll span the center just past the control horn with a piece of 1/16 wire. The ends of the wire are bent 90deg and a holes are drilled into the edge of the wood joiner for the wire ends to insert into. A groove is cut in the wood for the wire to recess into so it is flush with the outside edge. Wick some thin ca in there to hold it all together, haven't broken one yet done this way.
Glenn
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Old Aug 13, 2008, 10:41 AM
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USA, MA, Longmeadow
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Quote:
Originally Posted by glewis
That center section does look a bit weak. I have broken similar designs by bumping the elevator while putting the model in the car .Think I'll span the center just past the control horn with a piece of 1/16 wire. The ends of the wire are bent 90deg and a holes are drilled into the edge of the wood joiner for the wire ends to insert into. A groove is cut in the wood for the wire to recess into so it is flush with the outside edge. Wick some thin ca in there to hold it all together, haven't broken one yet done this way.
Glenn
Glenn, a wire joiner would certainly be a good fix. I just took the easy way out.....

Mark
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Old Aug 13, 2008, 12:50 PM
BYOP - Build Your Own Planes
Mountain Models's Avatar
United States, WI, Appleton
Joined Mar 2001
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Quote:
Originally Posted by glewis
That center section does look a bit weak.
Yup! I just forgot to replace part of it with 1/8" basswood. I meant to, but just had a brain fart. On mine, I ended up gluing some 1/64" plwood rectangles top and bottom in the joiner spot, as a temporary fix.

Brian
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Old Aug 14, 2008, 01:34 PM
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Wing construction

The wing starts with construction of the spars, LE, TE, turbulators and spar caps. The first picture shows, from top to bottom, the forward turbulators, the spar caps (top and bottom), the trailing edge, the leading edge, the rear vertical spar and the main vertical spar. All the spars are made up of either two or three pieces which are glued together. While the turbulators in the picture are notched for the ribs, Brian thinks he might just use solid turbulators (which the rear ones are).

The second picture shows the ribs slotted onto the two vertical spars (and I apologize for taking a picture of light colored balsa on a beige rug ).

The third picture shows the leading edge, trailing edge, and cap strips installed. At this point, I still haven't glued anything together. It's all just tabs and slots. You might also notice all of the false ribs that go from the main vertical spar to the leading edge.

Because it is a symmetrical wing, Brian has put building tabs, top and bottom on all of the full ribs, so that the wing can be held flat on your building surface, whether it is rightside up or upside down.

I will admit that when it came time to get the leading edge and trailing edge into place, it took me awhile. There are a lot of tabs and slots, especially at the leading edge. I experimented with starting to put the LE on in the center, then doing all of it a bit at a time, and finally starting at one outboard rib, and going across the length of the wing to the other tip. I found that this last method was the easiest to do. On the trailing edge, the rib is slotted as well as the trailing edge piece, and the ends of the ribs get very thin, so you do need to be a bit careful when you slot the trailing edge into the ribs. A little judicious use of sandpaper can also help!

I think it probably took me about an hour and a half to get to the point of the third picture, so it is still very much a quick, painless build.

Mark
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Old Aug 16, 2008, 09:50 AM
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From my last post, the rest of the wing builds pretty much instantaneously.

The first pic is of the wing with the turbulators installed. At this point, I have glued everything up.

The next pic is of the completed wing, with the wingtips installed, the servo mounts installed, and the exit support for the aileron servo leads. This pretty much finishes up the wing. The servo mounts are mid-aileron, so servo extensions are going to be necessary. Brian is recommending HS-55's all the way around for servos.

I'm pretty sure that building the entire wing took right around two hours, so I am around five hours at this point for the total build.

I did have a slight twist in one wingtip, which I'll take care of when I cover the model. I'm pretty sure that I didn't have an even, steady weight on the spar when I was glueing it up. As it's a single piece, forty inch wing, it's big enough that I probably should have used weights along the spar and trailing edge to keep everything perfectly flat. But I just used my arm, and basically glued up half of the wing at a time, turned it around, and glued up the other half.

To complete the structure, all that's left is the ailerons. Maybe 15-20 minutes to build them both.

My last picture is of the completed wing and ailerons. Total weight of the wing and ailerons is 2 1/4 oz, so it is going to be a very lightweight airframe.

Mark
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Old Aug 16, 2008, 10:02 AM
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Ready to cover!

Finally, my two "in the bones" pictures of the plane taped together. And of course, in the first one, the tape let go on the left aileron, just as I pushed the shutter.

The bare airframe weighs exactly 5 oz, after spackling, sanding, etc. There really isn't much sanding to be done, other than shaping the leading edge of the wing, removing any glue bumps, smoothing everything out a bit, and sanding in the bevels on the control surfaces. Brian is recommending tape hinges for the control surfaces, so that's what I will do.

The whole model really is a very quick, straightforward build. I would think that anyone who has built a couple of laser cut kits could easily build the ACE, and end up with a very nice airframe. It would probably build even more quickly with instructions!

If anyone following this thread has any questions, post them up and I'll be happy to answer, to the best of my ability.

Time to make the decisions regarding my covering scheme, and get that underway.

Mark
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Old Aug 16, 2008, 01:02 PM
It's a BIG park
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Killeen/Ft. Hood
Joined Apr 2007
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Mark,
Do you have any shots of the battery hatch ? Battery placement ?
And maybe the elevator mount ?

Ric
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Old Aug 16, 2008, 01:43 PM
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Ric, the battery hatch is basically between the LE of the wing and the firewall, on the top. You can see the fingerhole in the "bones" shots. I don't have a clue yet on battery placement, but it will just go on the crutch, slid through the hatch. There is a piece that goes on the bottom of the fuselage in the tail, through which the vertical stab slides, and locks into the slots in h.stab. It's a pretty neat design, actually, as when I did the "bones" pics, it all just locks in and self-aligns.

Mark
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Old Aug 16, 2008, 01:54 PM
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PrkFlyrRic's Avatar
Killeen/Ft. Hood
Joined Apr 2007
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Mark,
Thanks.
With the battery that far forward Iím wondering if the extra nose weight of the front wheel mount will push the battery back, closer to the CG for more battery size changes without changing the CG.
Hmmmm.
Watching your progress.
Ric
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Old Aug 17, 2008, 09:04 AM
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Ric, Brian has told me that on the prototype, with the nosegear, he did indeed have to push the battery back underneath the wing a bit to get the CG correct. As I am going to initially do the ACE as a taildragger, it will be interesting to see the difference.

After building the prototype, Brian also lowered the crutch in the fuselage sides a bit, as he felt it would make it easier to use a wider variety of batteries in the plane. My beta kit has the lowered crutch. That's a good example of the design changes Brian makes as he goes through each generation of a model's development. I'm sure there will be changes between my beta kit and the production kits, like the elevator joiner area. Another example would be, if you look at the pic of the ailerons on the cutting mat, you might notice that there are no control horn slots in the LE of the ailerons. Somehow they were lost when Brian transported the design files to the cut files for the laser. They're now back in the cut files. I cut my own slots, after the picture was taken. I've often told Brian that he has me do betas because if there is a way to mess it up, I'll find it and do it. But my errors and misunderstandings can help Brian figure out how to "idiot proof" a model, making it a better, easier build. I will have to say, however, that this one is very, very good as he sent it to me. That should mean he can bring it to market that much more quickly.

Mark
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Old Aug 17, 2008, 12:56 PM
It's a BIG park
PrkFlyrRic's Avatar
Killeen/Ft. Hood
Joined Apr 2007
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Quote:
Originally Posted by buzzltyr
That should mean he can bring it to market that much more quickly.
Mark
I'm all for that !

Ric
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Old Aug 18, 2008, 12:09 PM
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USA, FL, Tampa
Joined Jul 2002
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I finally started my build of the ACE last night. I started by checking the alignment of the motor mounting holes to the 400XT Xmount. The holes were only off by less than 1/16" so I wallered the holes out a bit with the trusty Dremel and installed the blind nuts. I found that the threaded sleeve of the blind nut is a tad longer than the firewall ply is thick so the nuts didn't pull flush to the surface at the back of the firewall. While not a necessary step, I like to CA the blind nuts to the firewall and they need to be flush to the wood for this to work. I pulled the nuts out of the wood and ground about 0.20" off the end of the sleeve, reinserted and glued them in place. Iíll get the nose strut mounting done tonight then the firewall subassembly is complete.
Unfortunately the use of Titebond will alter the assembly method of the model. I wonít be able to assemble the structure then hit the joints with a drop of glue like with CA. The assembly will have to be planed to allow the proper use of this type of adhesive. This will slow the construction a bit but I like to take my time anyway. I think I now have a good assembly plan and the glue will start to flow tonight.
Glenn
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Old Aug 18, 2008, 12:43 PM
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Glenn, I guess I never looked at the blind nuts on the firewall! I just pushed mine in and put a little drop of CA on the back side of each of them.

Although I worked all weekend, I did go into "maniacal covering mode" since my last set of pictures. I'm attaching a pic of the ACE all covered, basically in "ARF" form. So my covering scheme is revealed! Nothing as fancy as Brian's curved checkerboards, but still, I think, in keeping with an aerobatic sport plane theme.

Final assembly will commence momentarily.

Mark
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Old Aug 18, 2008, 01:00 PM
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Ithaca, NY USA
Joined Mar 2001
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Buzz, looks like you are getting close to finishing the ACE. Looking forward to hearing your flight report.

Doug
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