I've been flying my TufFlight Predator a lot recently in hopes of getting it ready to enter a combat event... or at least try combat with some of the guys here. One of the things that I have noticed in the trimming process is that the neutral trim condition for full throttle, level flight appears to change dramatically in a high-speed dive. If left alone, as the airspeed builds up, the Predator has a tendency to roll to the right. As long as I'm active on the sticks, it doesn't matter too much as I don't hold a vertical line or dive for very long.

My plane has had a few tough landings but is overall in good shape. I have noticed a bit more bending flex in the wing, I don't know whether the spar has delaminated or if it's just my imagination. In any case, has anyone seen this problem before?

Predator or Predator X?

If it's the origional Predator, try tightening up the covering a bit.

If that doesn't help, just don't fly that fast. I've twice seen Predators "flap" when the plastic spar manages to twist and buckle. In both cases the pilot was able to cut the throttle and land safely, but you should be aware that the spar on the Predator can buckle. In both cases, the Predator was really screaming along, easily going faster and turning harder than the design intended.

One of the two I saw was mine, btw. I am pretty sure that I had the RX and servo cutouts too close to the spar and that contributed to the problem. The OS .32F had on the nose was a factor, too, I imagine.

Montague,

Thanks for the advice. I'm flying the regular Predator. I understand that they've since made design revision to the base model, making mine two or three generations old.

The covering is pretty loose throughout the model. It looks pretty bad, although it flies well. For some reason, I could not get the bargain-brand covering to stick well to the EPP. As it stands, it's loosely draped over the wing

I have not incurred any instance of flutter or control surface buzz despite my best attempts. Perhaps this is simply because I don't have enough power. I'm running an OS 25FP turning a 9x4 prop. It launches well and is good for maneuvering, but quickly overspeeds in a dive.

Have you had to perform any maintenance on the spar or the glue joints? Also, do you have any idea how the Predator performs with a .32 compared with a mellow .25? Is it worth upgrading?

I didn't have any control flutter on my Predators either, that was never a problem for me.

You should tighten up that covering, or apply an X of tape, that should help the wing twisting. The Predator really needs that skin stiffness. (at least the older ones, I haven't seen a brand-new one, mine we bought around Feb of last year).

The .32 on the front of the Predator is awsome. I was going to fly a C class RCCA combat event, so I pulled my Mag .25 and put in the OS .32F, with a mousse can and an APC 9x5 prop. The power difference is stunning. It was easily the fastest plane at the event. However, getting ready for that contest, I did, in fact, buckle the spar really badly, the plane looked like it was flapping it's wings, really quite funny. A .32 is just too much power for a stock older Predator. I wound up "fixing" the spar by expoxying in some carbon fiber doublers on both sides of the spar. It flew ok, but I didn't get it straight, so the wing had a bit of a warp in it, and it snapped more than it used to because of the warp.

Other than fixing damage, I haven't had to do any "maintenance", but I actually didn't stay with the Predator design that long, I think I only flew them the first part of last year.

When I built mine, I was trying to keep the CG as far forward as possible so I wouldn' thave to mount the engine way out on the beams. So I put the servos, battery, and RX pretty close to the spar, and the servos were sideways. As a result, I think there wasn't enough foam on either side of the spar to stop the buckling under the loads the .32 caused.