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Feb 02, 2008, 08:46 PM
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Profile F-107 ultra sabre


Well, no motors in the mail, snow on the ground, and rainy all day, so I sat down to do my last profile build for a while, used up my depron and carbon. This is another one of my childhood favorites, an Ultra Sabre. This has a 23.5" wingspan, and 39" length. AUW for the dry airframe is 4 oz so far, 4 or so for motor and electronics, and then we'll see what battery it needs, I'm hoping I can get by with a 1320 pack, for a RTF weight of 12 oz. The wing is short so I'm going to us a full flying tail on this one, as I've got the thrust line and surfaces pretty much on the same line. Wing area is 174 sq inches, so loading should be still pretty light.

Enjoy.

Frank
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Feb 05, 2008, 12:33 PM
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Maiden flight!


I got my grayson 2212-06 motor(came with a free apc 6x4) and the towerpro 9gm servos last night and finished up the ultra-sabre, before painting. The tower pro servos seemed pretty nice, I've been using almost exclusively HS-55's, and these seem a little bit nicer and smoother for a little less $$. I was concerned that due to the weight of the grayson motor I'd need to run a 2100 pack, but being extremely careful in cutting out some lightening holes I was able to get the 1320 to work fine. I do think the grayson website needs to change their weight for this motor, don't get me wrong, I think it's a great motor, but 47 grams, it is not, the bare motor with leads as it comes came out 78 grams on my reloading digital scale. This can make a huge difference in a pusher parkjet for balance. As long as I know up front that's ok, but 47 grams it isn't.

AUW was 12 oz, right where I wanted it to be. I put the CG right where the glide tests said it would be a bit nose heavy.

Anyway, It was pretty gusty this morning, but no rain, so I fired it up, and away it went, just three clicks of aileron and two clicks of up was all. It really penetrated the wind great. I was running about 1/4 throttle to close to half and it was fast, I went full throttle twice for some zooms, unlimited of course. Roll rate with the full flying tail was ok at less than half throttle, not fast, if you gave it some throttle the roll rate was pretty decent, and axial. Loops were reduculously tight even on low throttle, no signs of stalling, couldn't get a real snap, just big barrels. It would hover into the wind at very very low throttle, low speed flight even downwind was nice and controllable, no bad habits. CG was spot on. I had fun just doing medium speed zig zags crosswind back and forth.

This is a really fun plane to fly in the wind, on final I kept just a tad of throttle so it would penetrate the wind, and just chopped as it touched down at my feet at zero forward speed. The maiden was so good, I got it wrung out and landed even before my 8 minute timer went off and I didnt' even bother flying the second battery. Now off to painting It looked great in the air, has a very nice profile and looks like a jet should look, painted will be even better.

Frank
Feb 06, 2008, 09:08 PM
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Flight video


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Last edited by burkefj; Apr 24, 2008 at 08:11 PM.
Feb 08, 2008, 04:53 PM
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Photos


Here it is with the paint and trim, still no stars and bars in the mail yet...

Enjoy

Frank
Feb 10, 2008, 03:51 PM
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Very interesting design, first time I have ever seen it!! Two questions: What size carbon flat did you use in the wing, and have you ever tried the KF-airfoil to improve speed or penatration? I miscounted: What adhesives are you using for general construction and what are you using to adhere your CF spars to wing?

Thanks, Strick
Feb 10, 2008, 11:10 PM
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Strick, the flat carbon in the wing, nose and tail, are .125 by .034. I slit the foam, run the end of the flat strip in the slot to make sure it is deep enough, press in with a ruler, then put foam safe thick CA over the slot, rub it in and hit it with accelerator. For the fuselage sandwich, I use UHU POR, contact adhesive, put on both sides, let dry for 10 minutes, and press together. Epoxy on the motor mount/pivot support for the tail, and foam safe CA for the wing/body joint, the joint is quite strong, fits very tight, and is about 3/4" wide, I slide the wing in, and use CA for a fillet, it will actually stay in place without the CA. I haven't played around with any airfoil at all, if you watch the video, in high wind, there is no problem with penetration, as I'm running at 1/3 to 50% throttle and it is penetrating fine, and I'm still using pretty square edges, if I was using a smaller wing on a heavier plane, I might experiment, so far my wing loadings/power has been such that it isn't necessary. Sometimes I'll use a 1/8" round spar, kind of depends on the wing loading, and span of the wings/shape for what I need. On all my spars, I also run a strip of blenderm tape on the underside of the wing, over the spar, it is flexible and also adds some strength.

Frank


Quote:
Originally Posted by Strick
Very interesting design, first time I have ever seen it!! Two questions: What size carbon flat did you use in the wing, and have you ever tried the KF-airfoil to improve speed or penatration? I miscounted: What adhesives are you using for general construction and what are you using to adhere your CF spars to wing?

Thanks, Strick
Feb 22, 2008, 10:27 PM
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Plans are now posted in the profile plans thread.
Apr 24, 2008, 08:15 PM
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Last edited by burkefj; Feb 27, 2015 at 08:25 PM.
Apr 28, 2008, 12:26 AM
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Nice airplane and flies great. Good videoography. The only one I've ever seen is in Dayton at the USAF Museum. Interesting project.
Bob
Apr 28, 2008, 09:38 AM
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Thanks Bob, I've always liked that plane, well, most of the planes from the 60's.

Quote:
Originally Posted by Bob757FL
Nice airplane and flies great. Good videoography. The only one I've ever seen is in Dayton at the USAF Museum. Interesting project.
Bob
Apr 28, 2008, 01:18 PM
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Quote:
Originally Posted by burkefj
...most of the planes from the 60's.
Vintage supersonic jets is my interest. Of course 50-60-70's airliners too.


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