Trim & Fly

There are few people who know more about flying indoor duration models than Bob Bailey, when he speaks I listen!

Here’s a new short article, Part 1 of 2 on how to get the best from your model in a low ceiling. Trimming.

Here’s Part 2 covering how to match your rubber to the model and conditions. Trimming2.

Need to get on better terms with your CG position? Try this article, once again thanks to Bob Bailey.

Keep a flight record using this little spreadsheet.

Below is a summary of a short article by Bernie Hunt in 2002 covering the initial trimming of the then new 55cm F1Ds, its still totally current.

“The new 55cm models fly with a much wider range of power than the old 65cm class. This can cause problems in trimming so I have attempted to set out my own understanding.

A stiff F1D model will fly at almost a constant speed throughout its flight, you should always try to launch at the correct attitude and speed, so that on high power the model does not set off too fast and potentially cause airframe distortion.
For the easiest trimming model initially choose a conservative prop. diameter and pitch. A nice rigid 18″ x 26″ FP prop. is easy to fly, will not return fantastic times but allow you to become familiar with the model’s overall performance and handling”.

Here are Bernie’s suggested steps that still look good to me:-

1) Assemble the model with 1/2″ tail tilt a little left fin offset and 0.2″ negative on the tailplane. The wing is at 0 degrees, no warps 2-3 degrees left sidethrust and a touch of washin on the port tailplane panel.
2) Fly the model on low power, say 10 gm. cm torque, and adjust tail tilt, fin and tail incidence until you get a nose up attitude without stalls and a 30 -40′ circle. The model should have about 0.25″ of wing wash in at this torque level.
3) Apply more power, about, and check that the circle does not open up. It may require more washin or sidethrust. The model should climb sedately.
4) Now fly on full power, on a 1/4 or 1/3 motor. If the model stalls whilst climbing and turn is still OK then shorten the bracing post by .030″, if it goes flat then increase the bracing tension by a similar amount.
5) Finally fine tune the trim by altering elevation, wing warps and stick bow until the model is in good trim in climb and descent.

6) Have fun, oh, there is never enough good flying time available……..

……and next comes setting up the VP prop. to maximise duration from Tony Hebb. Lots more fun to be had here and when you get to dreaming about what changes to make you know that you are finally getting somewhere close…..normally it just comes to you as you are driving away from the venue!