I opted for Hitec HS-77BB Low Profile Servos for the ailerons & flaps. They are 1 oz lighter than standard analog servos & at 77 oz-in, (6v) they have 35% more TQ than standard servos.

Even though they have considerably less depth, they are slightly longer & wider than the HS-425BB. I know they are meant to be mounted flat, (which I abhor) they still offered the best torque/weight package in a reasonably priced analog servo.

This required the servo trays to be modified slightly, but when I started working on the mount beams, I found the original construction sorely lacking in structural integrity. While the slots milled into the tray decks where 1/4", the mount beams where fabricated out of 5mm plywood & the glue appeared to be some sort of hot melt adhesive that did not achieve a good bond. Some of the mount beam could be broken free with some moderate twisting by hand & they all came free with a (very) little work with an Exacto knife.

Here are the original mount beams after removal. Note how the adhesive parted from the tray deck along with the mount beams.




If you plan on putting your Rascal 110 through high stress aileron maneuvers (as I am) you might want to have a look at the servo tray construction. Mine was one of the 1st batch from Vietnam so this issue might have been addressed by now.

I fabricated an insert for my table saw to use my 1/2" Dado blade. I sandwiched 4 layers of 1/4" poplar plywood with sacrificial layers of 1/8" birch plywood on the outside to prevent flaking of the plies.

Note the flaking on the 1/8 outer layers.




I used Scotch double sided tape (poster tape) to hold the layers together.




After finishing the shape with a disc sander & rasps, it was easy enough to use a #11 Exacto knife blade to separate the layers.

The tongue that mortised into the deck was left slightly long. After assembly with 30 minute epoxy & ample curing time this is what I had.



A quick swipe on the disc sander brought the surfaces flush





Here is the finished product with the low profile HS-77BB servo mounted and the standard size HS-425BB servo next to it for comparison.






Since I had no Transparent red Ultracote, I had to do something different for the finish color scheme. I will go into that in the next post later this evening.