Ola Fremming's homepage


Hyde-mount for builders

For optimal soft mounting of the engine in a competition model, nothing beats the mount designed by Merle Hyde, Chip's father.  In addition to being a very good mount, it is easy to make by each and everyone, from low-cost parts.  The mounts are available from Merle via several suppliers, but the price is high.  The cost emerges from the labor, not the materials.  I first saw this mount in Chip's Jecyll at  world-champ's in Austria 1993, and Merle kindly explained the details in how to make one for myself.  Since the 1994 season I have used my own made mounts exclusively, both on YS 4-stroke, OS 'Hanno', Webra 120/145 and OS 140RX, with excellent results in vibration damping.  Even though the materials involved are plywood, balsa and rubber tubing glued together with CA, the durability has not been an issue for me.  They lasts for more than one season of active flying, and then my needs are fulfilled. A short description of how to make one for yourself can be downloaded here (in Norwegian) : HydeFeste.pdf.  To further help those who want to try themselves, I have added some pictures taken during the building process of the one used in my Alliance (2000 season).  

The 4mm plywood disc's are finished, with blind-nuts for mounting. 10mm balsa is glued to both and cut down to almost same size as plywood.  Each assembly are the going to be sanded as circular as possible.  The sander is home-made from a DC-motor, a box and sanding disc. A hole for the tube of a vacuum cleaner avoids a hell of a lot of dust in the air.

Both halves are sanded circular and the balsa edge is rounded. By applying dope, with light sanding after each coat, the surface becomes smoother and more durable.

 

 A disk of rubber is glued to one piece. This disk generates friction damping when engine is at idle, and saves the balsa when electric starter is used

 

All parts, ready for assembly.

 

Thread is applied tight to press rubber onto plywood.

 

Thread is glued to rubber tube, take care to avoid spill of glue on other parts of the rubber tube.

 

After the thread is applied and glued, the rubber can be glued to the plywood.

 

When rubber is glued to plywood, cut the rubber flush with plywood surface using a sharp knife.  Then seal the surface with thin fiberglass cloth and thin CA.  This helps to keep the plywood and rubber together.

 

Excess material can be removed from the Dave Brown FS120 engine mount, this to reduce weight as much as possible.

 

To remove even more weight, most of the plywood is removed with a Dremel sanding drum mounted in a drill-press.  A weight reduction of 30- 40gram can be achieved by doing this.

 

Finished, with engine and nose-ring.

 

Aluminum nose-ring with fuel-tubing as O-ring.  Total weight with tubing is 13 g (less than 1/2 oz).  The cutout is made to make it fit in the Alliance.