Tuesday, 31 May 2016

Old dog and new tricks?

As a result of a conversation with Peter Gunning I offered to retrofit Peter’s recently acquired Freestyler 3 with the Servorahmen drive system and fit the model out with KST High Voltage servos. These servo mounts and control mechanisms are very robust and slop-free when installed.

Getting the existing RDS out was straightforward and just needed careful pulling out with pliers taking care not to overdo it! Getting the large horns and pushrods installed required a deal of cogitation but the end result is superb. The scariest operation was Dremelling the control surfaces to fit the substantial horns without damaging the wing skins. A steady hand and eye are required. The pictures show various stages of the installation.

This picture shows the whole servorahmen assembly from one of Peter's previous installations.

Test fit of servo in mount. This allows access to the servo retaining screws but not to the pushrod/servo arm.

Control surface horn in place. Getting the horn/pushrod assembly in place was a bit of a faff because the whole assembly is quite big and there isn't a lot of space. Glass tape to try to protect wing from any wayward Dremel cutting disc!

Servo mount epoxied in place. Note the two 3mm holes for access to servo release screws. Masking tape to protect wing skins. Servo connected to aluminium pushrod but not epoxied yet.

High Voltage KST servos in fuselage and time to hand back to Peter for final installation. The KST servos are smaller than the ones they replaced so a ply adaptor plate was made up and epoxied in place. Note the 1mm glass board raising the servo height and reinforcing the servo plate.

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