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Old Dec 31, 2012, 11:49 PM
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Captain Coolite
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Meringandan, QLD , Australia
Joined Jan 2011
2,960 Posts
Flaps Fitted and Tested, Serviceable

I have posted my Build and Maiden flight review on my blogg for the PC9.

I decided that the model did need flaps to help slow her down for landing on the rough surface of my park.

Before I did anything I gathered all required materials and had a very good look at the wings, and studied some photos of PC9's landing with flaps deployed.

That done, I decided on some down and dirty Zap Flaps which are not quite scale, but I had to leave some wing at the root so that structural strength of the wing was not compromised.

I marked up all of the areas where I'd have to take the scalple to the foam, measured carefully so that each side was a mirror image of the other.

The most time consuming part was finding 2 servos in my parts drawer which would function in the same direction. (thank goodness for the HK servo tester)

Once everything was marked up, I took a brand new hobby knife and made my cuts. The first was the servo recesses, then the servo lead channels, then the flaps were cut away from the wing. I then had to cut the hinges into place. These were carfully measured so that they were the same on each side.

I found some short servo rods which were ideal for the job, and then I measured and fitted the horns so that they had maximum strength and provided maximum throw.

All glueing was done with Zap 5 min epoxy.

Before glueing anything, the flaps were dry fitted and tested with the Y lead plugged into the servo tester.

Once all was correctly fitted and glued, I programmed the radio for 3 positions. Full Up, stage 1 and Full Down.
I used the servo slowing function on the DSX9 to slow the deployment of the flaps, so that any pitch attitude changes resulting from deployment were slowed. I did, however, make the retracting of the flaps as normal so that if anything were to go wrong when the flaps were deployed, then I could get rid of them quickly and sort out any other issues immediately.

The test flight.
I did a normal flapless take off, then climbed to height (60 + feet).
I brought the model around onto a long upwind, then deployed first stage of flaps.
No noticeable pitch attitude change.
I repeated the process for full flap with the same result.

On landing, I deplyed full flap on base turn, then brought her in.
On short final I chopped the throttle then used elevator to control the nose attitude as she sank in.
I was able to conduct a very well controlled landing as the flaps allowed the model to float through nicely as the speed bled off.

SUCCESS.

The next trick was to try using flap for take off.
I used first stage of flap for take off, which brought the model off the ground much sooner, permitting a very nice , scale looking, departure.

This has been the first time I have attempted to modify a model in this way.
Thanks to posts from others on various threads on how best to install flaps on a model, I have been able to considerably enhance my flying enjoyment of this model.
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