Ply Frame For Blue Bird BMS-125, BMS-126 & BMS127 (Pair)

These HyperFlight CNC cut ply servo frames make fitting a BMS-125WV, BMS-126WV or BMS-127WV servo to a molded wing very easy. No thickness is added to the installation, and the servo is mounted securely, yet can be removed easily if required.

Two servo frames supplied in the pack.

How To Mount Wing Servos Using Ply Frames

1. Glue a strip of 3mm (or 1/8”) balsa to the leading edge of the mount (width dependant on the distance the mount is likely to be behind the main spar).
2. Place the mount with the servo in-situ in the wing and abut it against the rear of the main spar.
3. Slide the mount sideways until it is in the correct position laterally and determine how much the width of the 3mm balsa needs to be adjusted for the mount to be in the correct position fore and aft.
4. Trim balsa to size. Reposition servo mount in wing and when happy with position draw a pencil line around the outside of the mount.
5. Remove servo from mount and epoxy mount into wing taking care not to get any epoxy in the inside of the mount which will prevent servo sitting properly in the mount.
6. Set up and adjust servo control rods as required. When satisfied glue servo in position using silicon / bath sealer and allow to set overnight.

To remove servo gently lever out with a suitable small screwdriver, allowing time for the sealer to break its bond between the servo and the wing.

Do not epoxy the mount in place with the servo in-situ for two reasons. A) It gets in the way when trying to place the mount. B) It introduces side loads which have a tendency to move the mount out of position whilst the epoxy is setting.

To minimise control surface slop the servo must be mounted as rigidly as possible. In molded wings this is greatly assisted by bonding the servo to the bottom wing surface, using a suitably shaped wooden block. Similarly attaching false ribs to the inner and outer edges of the servo bay will mechanically connect the upper and lower wing skins, increasing rigidity.