Gretz's Force

z

Zuriel

It runs good. I fitted it with the OS tuned pipe that is designed for the motor. However I had to cut the exhaust pipe shorter by about an inch. In the pipe world that is a mile. It would turn a 10x5 apc at about 10000 and at 9800 it was really strong on that prop. It seemed much stronger than the regular 26 surpass. It has twice the exhaust pipe diameter coming off the head. At full needle it it is pretty loud not like a regular 4s. It also looks really cool being black. I put on an 8x4 apc and it went 15100 rpms! It got on the pipe and there was not looking back. I ran it on sig 25% nitro. It was really loud and cool sounding. This is where I will try some experimenting. I will try smaller props at outagous rpms and see what happens. It is now fitted with an FP 25 venturi. It is a dream to needle. Do you remember what props they tried on it. All I need is another 26 crank and I could have another motor to compare it to. Where can I get one?

DMoon

Mike Pratt

Mike (not Gretz) Pratt

I have reviewed previous threads about your plane and most of the the great "flappless" submissions. Would you compare the "Primary Force's" performance to that of a flapped ship? Your theories? 'hope I'm asking this on the right thread. Thanks.

SK

Your question about flight performance of the Primary Force compared to flapped models is a hard one. I think it is more a matter of building, trimming skills, and flying abilities. If you have all those skills then it really doesn’t matter which one you choose because they both can be made to fly really well. In my humble opinion it is much easier to build, set up, and trim a flap-less stunter than a flapped stunter, especially for pilots lacking some of the trimming skills.

I have been to many contests where I have seen models being flown that were really out of trim and the pilot has just learned to put up with all the funny zigs, zags, and wiggles that his model was performing throughout the pattern. Again, it is my opinion that a trimmed flap-less model is way better than an out of trim flapped model. The most recent advancements that helped flap-less models become more competitive is the modern high revving engines that are equipped with flat-pitched props. This engine & prop combination allows the model to fly at a constant speed with little to no wind up in consecutive maneuvers.

The design concept for the P Force started just after I finished designing the Skyray .35. I built a Fox powered Skyray .35 racer for my wife and installed a 4” bellcrank to slow the controls down. This Skyray turned out to be a really fun and good flying stunt model. It had only one problem and that was it had a tendency to wind up with the Fox .35 in consecutive maneuvers. At this time Fox had just released the new BB .25 engine and I installed it on the Skyray racer along with a 10” x 4” nylon prop. This thing turned out to be a hoot. It didn’t take long for me to start thinking about how to improve it (as it turned out Brett Buck had the same experience with his Skyray).

The design intent of the P Force was to design a simple to build and easy to trim (no flaps) model that had many if not all the aspects of a full-blown stunt model.

To sum this all up, Yes! I think a properly designed flap-less model with the right pilot can be as competitive as anything out there.

Mikey

Thanks
Mikey