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Old Sep 10, 2013, 12:07 AM
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i dont get much replies on the fuel jet so i posted here with a question

MY F-15 now has a 32 pound thrust engine and is repainted with gear doors and the works. Please see picture below. MY total flying weight is coming in at 45-46lbs now. THE jet is 15lbs over its natural flying weight. IT will be about 37 as the flight comes near its end because I have 150oz of fuel in there which will get burned off. I think for the size of the plane the weight is okay but not sure about the internals. SO if you have more weight it only seems natural with speed and weight it creates more stress on the frame. I am worried the wings will fold on it. So it has two aluminum spars which are solid not hollow that go into the fuse via plywood formers. THE front of the wing has like a nylon screw that holds the front of the wings and the back aluminum spar gets wedged in with a large hex screw. I have flown it fine at 34 pounds with the smaller engine, I have also flown it with the larger engine but it was a very short flight as the fuel got low and flamed out with in 5 mins. SO to extend the time I went with another 50oz tank to have total of 150oz. Before with the VT-80 I was getting about 12 mins flight on 100z tank. NOW with the kingtech 140g im getting less than 6mins on 100oz. SO I was like I have a lot of room and added another 50oz tank to get few more mins. SO do you guys think with the extra paint and fuel weight it may be a problem? OR will it still fly like a kite even with the extra thrust? I was pushing 17 average out of the tail now im getting about 30lbs coming out, but also the jet is 10-13 pounds heavier
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Old Sep 10, 2013, 12:08 AM
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picture

man its nice.
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Old Sep 10, 2013, 12:20 AM
deltas are cool
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Joined Apr 2006
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yikes that is a big weight gain and speed will go up too ,which will add more G load. so you are saying your alum spars are solid aluim. or they are tubes? i would beef up spars and carry throughs /bulkheads and take it easy onb g's your way passed what it was intened to fly with
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Old Sep 10, 2013, 03:48 AM
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solid

solid, two of them, they are rectangular shape. HERE is the back of the jet by the way. I was thinking having a spar go through but the fuel tanks are in the way. I think xps Byron f-15 weight is near mine as well, not sure what they did on the inside of the fuse though. Im thinking about taking the aeroepoxy and going over all the formers inside the jet on top of the glass work that is there, not sure if that would help or just add more weight.
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Old Sep 10, 2013, 03:49 AM
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picture

picture
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Old Sep 10, 2013, 12:04 PM
SoCal, Year Round Flying!
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Most of the turbine crowd are on rcuniverse....
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Old Sep 10, 2013, 06:31 PM
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upland CA
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The weight gain is not what will kill your jet..it will just stall at a higher speed...the higher top speed that you will get may be a problem..but if you dont yank it around too hard it may not be a problem also..But a hard laning will add a lot more stress at this weight
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Old Sep 10, 2013, 10:35 PM
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If its built like a typical byron with aluminum blade spars embedded in foam cores and then just glassed over the top with 1oz glass, you'll probably pull the wings off the aluminum spars.
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Old Sep 11, 2013, 07:23 AM
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Yea going to have to take it easy

the turbine puts out about 32 pounds. WITH a split pipe will lose some power but will mainly use it to climb. I don't think I will be doing full speed passes with it. Will add power on climb outs and into turns.
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Old Sep 11, 2013, 08:56 AM
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United States, OH, Columbus
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Quote:
Originally Posted by invertmast View Post
If its built like a typical byron with aluminum blade spars embedded in foam cores and then just glassed over the top with 1oz glass, you'll probably pull the wings off the aluminum spars.

Thats my fear with my Byron F16 as its nice aluminum spars in foam.

Im getting read to skin my wings and was thinking in a few locations adding little 3 in strips of light ply going from nose - tail of the bird to help spreed the load over the spar in the foam
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Old Sep 16, 2013, 06:22 PM
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Should be fine, go fly and video. Please
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Old Sep 16, 2013, 06:55 PM
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we are making the new formers in the jet to be thicker

Wednesday, that should hold the wings in good. Maiden flight should be sometime this week.
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