Ultra flash out of trim at full throttle.
#28
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Join Date: Feb 2005
Location: Hahifax, NS, CANADA
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I flew my flash all last summer without any trouble and then all of a sudden I noticed the same problem.
For me it turned out to be the little centering tabs in the back of the exhaust tube kind of flatten out a small amount.
You really didn't noticed it on the ground but I pulled the tube and bent then a little more and presto the problem went away.
Hope this helps
Al Coolen
For me it turned out to be the little centering tabs in the back of the exhaust tube kind of flatten out a small amount.
You really didn't noticed it on the ground but I pulled the tube and bent then a little more and presto the problem went away.
Hope this helps
Al Coolen
#30
If your plane is climbing with increased airspeed and the incidence is set right it's probably just a little nose heavy ... regardless of the manual CG. For good reason manuals would prefer you error toward a nose heavy CG.
A stable plane is designed so that when it starts loosing airspeed the nose will drop a little and pick up airspeed. The down-force on the horizontal stabilized reduces with the decrease in airspeed and causes this to happen balancing at the CG.
If the CG is too far forward you are trimmed straight and level you are flying with excessive down-force in the horizontal stabilizer. As the airspeed increases this becomes greater and greater and causes the nose to climb. It is much better to have this, than too far aft CG.
Too far aft, the nose will drop with excessive speed but when you are flying slow the nose will start to climb, slowing the plane and causing the nose to climb even higher causing an imminent stall.
That is why it's better to be too nose heavy rather than too tail heavy.
So a healthy stable airplane will climb very slightly with increased speed, also very true with full sized aircraft. If it's climbing too much, move the CG aft a little. If it ever has a tendency to descend at higher speeds .. the CG is too far aft and will be unstable at low air speeds.
A stable plane is designed so that when it starts loosing airspeed the nose will drop a little and pick up airspeed. The down-force on the horizontal stabilized reduces with the decrease in airspeed and causes this to happen balancing at the CG.
If the CG is too far forward you are trimmed straight and level you are flying with excessive down-force in the horizontal stabilizer. As the airspeed increases this becomes greater and greater and causes the nose to climb. It is much better to have this, than too far aft CG.
Too far aft, the nose will drop with excessive speed but when you are flying slow the nose will start to climb, slowing the plane and causing the nose to climb even higher causing an imminent stall.
That is why it's better to be too nose heavy rather than too tail heavy.
So a healthy stable airplane will climb very slightly with increased speed, also very true with full sized aircraft. If it's climbing too much, move the CG aft a little. If it ever has a tendency to descend at higher speeds .. the CG is too far aft and will be unstable at low air speeds.
#31
My Feedback: (3)
That's an excellent way to describe what is happening. Particularly with the UF, it has a huge speed range. While straight and level at all speeds and thrust settings would be great, we do not enjoy flying planes that "tuck" or dive at speed or with power. Better to err on the stable/safe side.
#32
My Feedback: (7)
Yes, thanks to SteveKott for a great explanation. I set all my aerobatic aircraft up on the verge of tail heavy to minimize unwanted deviations during aerobatics. As a result I have to live with aircraft that want to "float" in the landing pattern and require careful attention to keep them from slowing themselves down too much. Planes set up this way don't want to glide. But during a nice low slow roll the length of the field, close to the ground and hauling *ss, I would not have it any other way