*** Ultra Sport Brotherhood ***
#2702
They're the CA kind. I know I could do the re-covering with the control surfaces in place - I was hoping to not have to do that, as I've never put covering on an airplane before, and I was hoping to make this as simple as possible.
#2703
Join Date: Mar 2013
Location: Winnipeg,
MB, CANADA
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ca hinges should be easy enough to cut so that should work, you can also cut your flaps so they have a hinge close to the end so you don't have to mess with that, and you will only have to seal the flaps. It is not hard to seal the hinge gap, just deflect the control surface to the max, and with a 3/4" strip of covering iron it on. Hinge gaps should be sealed anyway, or so I have been told. Lately when I seal a hinge line I do not seal at the hinge and it makes for a much neater job, but either way with a little practice it is fairly easy to do.
Calvi
Calvi
#2705
Join Date: Mar 2013
Location: Winnipeg,
MB, CANADA
Posts: 751
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Ok, if you do cut out the flap use a razor saw if you have one and use a square to cut them at a nice 90 degree angle, no one else may notice but you will, of course you can sand them square if things do not go according to plan.
#2706
Join Date: Mar 2013
Location: Winnipeg,
MB, CANADA
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to use your aileron servo for the flaps, all you have to do it make a "y" pushrod, this is just two rods soldered together, nothing fancy wrapped with wire soldered with plumbing solder(lead stuff if you have) or electonics type solder. I can post a pic later when I get home from work if you like.
#2708
Can someone post a picture/textual description of the aileron pushrod servo and how it's mounted? I Imagine I don't want to cut through the center rib beneath where it used to be.
#2710
Doing it right now. I spent the yesterday with a bunch of sandpaper and acetone trying to get the color out of the wood. There's still some there, but it almost looks like regular wood now. I'll add a few pictures later.
#2711
I cut the ailerons out and guess what--the wing has already been rehinged! I couldn't figure out why one cut was taking so long, then I realized I was cutting through a hinge that had already been cut off (so I couldn't see it when I looked through the gap)--and it was the plastic with a fixed brass pin kind. Other than that, it went smoothly. The cuts are pretty good, and the CA hinges came off quite easily. Unfortunately, the hinges weren't at the same locations on each wing, so to get the amount of flap/aileron I wanted I had to cut in the middle of the actual hinge on one side, so now one of the flaps is still completely hinged, but the other needs another outboard hinge.
#2713
Didn't quite get it done. The control surfaces on the wing still have to be rigged and covering put on, but that's all.
I am a bit worried that I sanded too aggressively--there are a few spots where the wood is noticeably thinner than it was previously (most worryingly at the root of the horizontal stabilizer), but not by much. Should I be concerned, or is most of the sheeting wood on there only to give it shape?
I apologize for the bad quality; my cellphone camera's not the best, nor is the lighting in my dad's basement. I'll take some proper photos with my DSLR when it's done. Nevertheless, I present you with a few of the in-progress pics:
Probably the only picture we'll see of it "gear up," just after I got the tri-gear off. Took a ton of sanding and acetone to get the brown out of the wood--both before and after this photo.
I must be one of the "ham-fisted" people they mention on page 27. Put this hole in the wing with my fingers. I'm sure you can see why repair attempt #1 didn't work. I don't have any photos of the finished product, but attempt #2 went a lot better--the wing has a scar, but it's smooth.
Next up were the plywood reinforcements for the new landing gear. I forgot to put the blind nuts in place before gluing the wood in for the tailgear. Fortunately, I had a 4-40 tap handy (my favorite tool, though I'm not entirely sure why). Unfortunately, hand-drilling through a half-inch of plywood was not fun. I ended up using 3/16 ply for the main gear with 1/4 basswood CA'd to it, because I removed slightly too much wood to make it flush with 1/4 inch ply as I had hoped to use. The balsa strips on the front and back are sanded smooth against the gear, nose, and wing. Gotta minimize that parasite drag! Also took some photos to preview the new gear.
Not sure how people usually rig the aileron pushrods in these. I chose to cut the pin out of one of the brass clevises that came with the Sullivan flexible pushrod kit and put it and one other on the servo as seen here. Works pretty well! Secure, free, and no slop.
And lastly, a few preview pics. Only had time to get covering on one aileron and the rudder over break. Since then I've half-finished the second aileron. I'd hate to have to do them without taking them off--have to do it for the elevator and flaps though. Overall, I'm pretty happy. Also, what I'm most excited about: I've removed the pilot figure to make room for a GoPro mount. Should have some exciting videos once I get it back in the air!
I am a bit worried that I sanded too aggressively--there are a few spots where the wood is noticeably thinner than it was previously (most worryingly at the root of the horizontal stabilizer), but not by much. Should I be concerned, or is most of the sheeting wood on there only to give it shape?
I apologize for the bad quality; my cellphone camera's not the best, nor is the lighting in my dad's basement. I'll take some proper photos with my DSLR when it's done. Nevertheless, I present you with a few of the in-progress pics:
Probably the only picture we'll see of it "gear up," just after I got the tri-gear off. Took a ton of sanding and acetone to get the brown out of the wood--both before and after this photo.
I must be one of the "ham-fisted" people they mention on page 27. Put this hole in the wing with my fingers. I'm sure you can see why repair attempt #1 didn't work. I don't have any photos of the finished product, but attempt #2 went a lot better--the wing has a scar, but it's smooth.
Next up were the plywood reinforcements for the new landing gear. I forgot to put the blind nuts in place before gluing the wood in for the tailgear. Fortunately, I had a 4-40 tap handy (my favorite tool, though I'm not entirely sure why). Unfortunately, hand-drilling through a half-inch of plywood was not fun. I ended up using 3/16 ply for the main gear with 1/4 basswood CA'd to it, because I removed slightly too much wood to make it flush with 1/4 inch ply as I had hoped to use. The balsa strips on the front and back are sanded smooth against the gear, nose, and wing. Gotta minimize that parasite drag! Also took some photos to preview the new gear.
Not sure how people usually rig the aileron pushrods in these. I chose to cut the pin out of one of the brass clevises that came with the Sullivan flexible pushrod kit and put it and one other on the servo as seen here. Works pretty well! Secure, free, and no slop.
And lastly, a few preview pics. Only had time to get covering on one aileron and the rudder over break. Since then I've half-finished the second aileron. I'd hate to have to do them without taking them off--have to do it for the elevator and flaps though. Overall, I'm pretty happy. Also, what I'm most excited about: I've removed the pilot figure to make room for a GoPro mount. Should have some exciting videos once I get it back in the air!
Last edited by stankinator; 04-08-2015 at 12:07 PM.
#2716
My Feedback: (17)
I am a bit worried that I sanded too aggressively--there are a few spots where the wood is noticeably thinner than it was previously (most worryingly at the root of the horizontal stabilizer), but not by much. Should I be concerned, or is most of the sheeting wood on there only to give it shape?
This part of your comment jumps out at me. The sheeting on the tail surfaces is where they get their strength. If memory serves me the sheeting on the tail surfaces is 1/16", easily sanded through if not careful. If you've sanded too much at the root of the stabilizer then it will need to be reinforced. Either by laminating another piece of balsa sheet over it or by laminating fiberglass in the area where it has been weakened. The horizontal stabilizer is under a great deal of stress during certain maneuvers such as pulling out at the bottom of a steep/fast dive. If it's weakened it will break sooner or later. I've taken my plane up high and dove it back down to pull out at 40 or 50 ft. If the plane is close enough you can actually see the stabilizer flex under the load.
This part of your comment jumps out at me. The sheeting on the tail surfaces is where they get their strength. If memory serves me the sheeting on the tail surfaces is 1/16", easily sanded through if not careful. If you've sanded too much at the root of the stabilizer then it will need to be reinforced. Either by laminating another piece of balsa sheet over it or by laminating fiberglass in the area where it has been weakened. The horizontal stabilizer is under a great deal of stress during certain maneuvers such as pulling out at the bottom of a steep/fast dive. If it's weakened it will break sooner or later. I've taken my plane up high and dove it back down to pull out at 40 or 50 ft. If the plane is close enough you can actually see the stabilizer flex under the load.
#2717
Yeah. That was the only part that really worried me. I don't know if it's a full sixteenth, but if you run your fingers over it you can feel a dip in it where it's been sanded too much. I'll put some fiberglass over all the roots this weekend.
#2721
My Feedback: (17)
Yes, one for ailerons and one for flaps. I can't claim credit for the idea though. I followed Minnflyer's build thread where he had several ideas to improve the Ultra Sport 60. All of which I used when I built my last US 60.
http://www.rcuniverse.com/forum/kit-...ld-thread.html
http://www.rcuniverse.com/forum/kit-...ld-thread.html
#2722
I used the same techniques, inspired by the same source. Except mine was all done after someone else did the initial construction, so the wings are remaining not sheeted among other differences.
#2725
Here's the manual. I couldn't find the acceptable CG range in it though. It says something about CG marks, so I presume they're cut into the wood or appear on the plans somewhere.
http://manuals.hobbico.com/gpm/us40-manual.pdf
http://manuals.hobbico.com/gpm/us40-manual.pdf