Hey guys,

On my F-15 and my T-45 at half throttle my jets are flying level anything above half they start to climb on there own. They have to be balanced some what right because I have many flights on both of them. They might be off a little but not enough to crash the jet for being off balance. Is this common with all jets or are my jets just unique. I have been planning on mixing elevator to thottle but just havent....

Thanks

David

David try putting a washer or two under the front of the engine mounts. This will apply a little down thrust to the engine. I have had to do this also. Pretty common.....easy fix.

Won't adding downthrust with washers just create a hot spot in the tailpipe? I've done the washer trick on externally mounted turbines, but does it really work with a tailpipe? I would think you would need to reposition the angle of the turbine and tailpipe, but I've never tried it. My Fury climbs a bit at full throttle, so I'd like to fix it, too.

make up a couple of shims out of thin alum and put under front of turbine sound like a thrust angle prob mine did it as well

I do a combination of the two for whatever makes the most sense. If I need to carry a little mix on elevator to throttle I do it. Washers, that too!

David,

There's nothing wrong with your plane. An aircraft is supposed to climb at full throttle, if its been trimmed to fly straight and level at half throttle. The increased airspeed creates increased lift. That energy has to be accounted for by either climbing or, retrimming the surfaces to redirect the energy. The reverse is also true, If you trim the aircraft to fly straight and level at full throttle it will want to dive at anything less than full throttle.

David S

I I like trimming mine to fly straight and level at full throttle. Like David said, all planes will want to climb with more airspeed. Some worse than others. I like a little down attitude on landing. Trimming the elevator down on full throttle Helps keep the nose down on landing and you don't have to worry as much trying to keep the nose from pitching up on its own. Just my personal preference. Everyone has their own. Shims would do the same thing I guess but you loose some of your trim authority.

I suggest trimming at what is your regular flying speed. So if you normally fly at 3/4 throttle, trim in that point. That way you will be very confortable when flying most of the time.
I normally use full power only for verticals or other manouvers that require more power.

Michel

What he said,
Wings and Most jet fuse's are designed to produce lift. the faster they go the more lift they produce. unless they are fully symetrical.