If you want your plane to loop tighter, try adding some washout. Here's how:

Apply twist to the wing so that the wing panel tip is twisted down at the LE and the TE twists up. Take a covering iron and iron out wrinkles that appear in the covering while holding the twist -- especially from the center of the panel to the outer third section. Don't heat the other wing half yet. Remove heat and smooth covering while it cools. Don't forget the wing bottom covering either. Now repeat for other wing half.

Fly the plane and make sure you have not introduced roll trim imbalance. If so, then twist again and heat only one wing panel to add more wash out to the panel that produces the correct roll direction to even out the aileron trim. Fly again to check roll trim and then check how tightly you can loop without snapping. Within a few iterations you'll have a tighter looping plane.

1. Not enough 3M77 spray used to adhere covering.
2. Incorrect hinge and/or TE shape causing flutter.

What you're seeing is the onset of full wing flutter. If left unchecked, the hinges will probably separate, and you may break something which will leave the plane uncontrollable. Land the plane immediately, and examine the hinges for tightness and make sure they pivot only along the thin hingeline, and the covering is not lifting away. If it is, you'll need to re-iron it down or maybe replace the covering if it's fuel soaked. If our hinging directions are followed, with strips of covering to locate the hinges, it's nearly impossible for the hinges to come unstuck. What may have happened is some 3M77 may have been applied between the covering in the stages where the covering is supposed to stick to itself. We do outline where it's important to guard against 3M77 getting where it's not supposed to be, so please follow the instructions and detailed pictures. If done correctly, you will have no problems.

Mark has several Predators that have absolutely no high speed "red line" and he often will perform a "flutter check" by entering a dive at full speed to see if his plane flutters as part of his maiden trim flight. Some actually do start to oscillate, but many do not. By all means, if you detect flutter, be wary of this speed and don't attempt to exceed it. If you did a good hinge job, you won't need to worry about flutter separating them.

In combat, it's very rare to need to do full speed dives anyway, because everyone is constantly looping and turning. If someone is diving, they are running away! Perhaps the only time you'll need to really dive your plane during combat is just after the "begin combat" signal is given, after you've been waiting for all planes to get airborne. After this, you'll be doing lots of "furball flying" in which case you'll be turning tight, and the plane will be slower.

If you're worried about flutter, be sure to use a very wet joint on the main brace assembly (don't let it dry!) don't cut any lightening holes, be sure to sand the TE and elevon shapes we outline, use plenty of 3M77 for the covering, and be careful to follow our directions when hinging and you'll have no trouble.

Version 5.0 of the Predator uses a main brace doubler, and longer front brace than previous versions. The resulting wing is noticeably stiffer, and this makes building skill less critical -- so you won't need to worry about this problem any longer.

To bend the mounts back into a straight position, simply dis-assemble them from the plane and engine, then bend them back using a vise and pliers. You can do this at the field with two sets of pliers also.

Note: The engine angle is really not all that critical, as you should be able to fly your plane well even with engine offsets of 10 degrees or more. Joe has personally survived several mid air collisions during combat that has broken one bolt, leaving the engine cocked to the left or right, at a strange up or down angle, and continued to fly the entire round! Of course, the plane was not optimum in this condition, but this illustrates that even thrust angles of 30 degrees left up or down can be handled in flight.

The best choice to save weight in a 5 cell pack is a "2/3 AA battery often called "AAC" battery. You can solder your own cells together, or if you prefer, Electro Dynamic (734-422-5420) offers this pack (6V, 350 mAH) ready to use. Its model number is 5N-350AAC for $18. It has five cells and has the same height as the 270 mAH packs we recommend for the Panther and Predator. Be sure to charge your pack every 2 or 3 flights as we're saving weight here, and you do get less air time with 5 cells.

Incidentally, this is really THE ONLY way we know to break one of our airplanes which has been built correctly. It's next to impossible to render one of our designs unrepairable at the field with a plane vs tree, plane vs ground type of impact. It takes two planes for this type of impact damage, and the "T-Bone" collision finds the only achilles heel. (no plane out there can survive this type of collision, BTW). Some "T-Bone" impact damage can be repaired with splints of plastic or thin plywood gooped in place across the separation.

Also note : If you have the "single elevator" version (with no transmitter elevon mix used), 30 to 45 degrees of elevator travel may be used for the elevator. Adjust aileron travel to your taste.