Just remembered this...so I'll ask, another trimming question

[Matt Colan]

My grandfather's F-14 is powered by a PA .40 pipe and weighs 70 ounces.  The plane has a chipmunk airfoil with the wing extended 2 inches on both wing panels.  This plane he flies very well and turns a good corner for an overweight plane.  On the square 8s, I noticed it went soft on the top half of the inside square.  I asked him if it did go soft and he said yes.  What could he do to eliminate that problem?

[Richard Oliver]

Matt,the outboard wing is probably ridding up a bit. Tweak the flap or tape on a small tab to check if this is the problem and then tweak the flap.
RO

[Brett Buck]

My grandfather's F-14 is powered by a PA .40 pipe and weighs 70 ounces.  The plane has a chipmunk airfoil with the wing extended 2 inches on both wing panels.  This plane he flies very well and turns a good corner for an overweight plane.  On the square 8s, I noticed it went soft on the top half of the inside square.  I asked him if it did go soft and he said yes.  What could he do to eliminate that problem?

   I am not sure what you mean by "soft". Less tight corner, or light on line tension (or both)?

    Brett

[Howard Rush]

When we're on the ground or when aloft,
The JCT does not go soft.

[Matt Colan]

   I am not sure what you mean by "soft". Less tight corner, or light on line tension (or both)?

    Brett

Light on line tension is what I meant Brett

[Joe Yau]

On the square 8s, I noticed it went soft on the top half of the inside square.

Would that be just after the 2nd corner or the 9th corner?

[Matt Colan]

Would that be just after the 2nd corner or the 9th corner?

Just after the 9th corner.

[Joe Yau]

What it sounds like is the engine running out of steam after the 9th corner, and then the 10th and 11th corner will be very light on line tension, make it hard to do a tight corner (due to the drop in engine power).  It should recover on the 12th though. I guess you could try flying the Square-8 a bit bigger and corners slightly softer, or go to a bigger engine without adding too much weight.. 70oz is a bit heavy.

Edit: in some case, finding some way to cool the engine more helps too (more oil etc).

[Matt Colan]

What it sounds like is the engine running out of steam after the 9th corner, and then the 10th and 11th corner will be very light on line tension, make it hard to do a tight corner (due to the drop in engine power).  It should recover on the 12th though. I guess you could try flying the Square-8 a bit bigger and corners slightly softer, or go to a bigger engine without adding too much weight.. 70oz is a bit heavy.

Edit: in some case, finding some way to cool the engine more helps too (more oil etc).

The PA does not miss a beat that I can tell during the flight.  This plane is a semi scale F-14 and the really is no cowl.  The motor and pipe are exposed and nothing is concealed.  He is thinking of refinishing this plane to lose some weight and get a PA 40UL for more weight loss.  The plane is a bit draggy because of the air intakes and the twin tails.  Also there is no fuselage taper.

Grandpa does have to nurse this plane in some spots because of the weight.  He has to start the corner early because if it is too tight, the plane sags and it could just pancake into the ground and that almost happened once.  But the plane looks rock steady and he does fly a good pattern with it.