Kyosho Ferias: How to mount a sp380 on a firewall? - RC Groups
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Jul 02, 2001, 01:23 AM
Registered User

Kyosho Ferias: How to mount a sp380 on a firewall?

Folks, I have the remnants of a Kyosho
Ferias that I'm repairing after a crash
due to a radio glitch. The sp380 motor
was held in an aluminum hose-clamp like structure mounted on a couple of plywood
arms that stuck out from the firewall. The
arms broke off in the crash and I'm
wondering how mount it witn some 'give'
in the mount so that minor contact of the
prop with the ground on landings wont
rip off the motor. The original mount wasnt
bad but its hard to repair without taking
off the firewall and i'd like to patch up
the firewall with some plywood and mount
the motor on it.

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Jul 02, 2001, 01:54 AM
Registered User
The original Ferias Motor mounts were notoriously weak anyway... A simple hard landing without prop contact would be enough to snap the two pieces of wood.

I have seen several "fixes".

1. Run 2 1/4" dowels about 8" into the fuselage, use rubber bands to hold down the motor.

2. Replace and reinforce the original mounts. This time the motor was mounted on 1/2 of the clam-shell mount and rubber bands were used.

3. Bolt up a nylon/glass motor mount for a .15 size engine to a plywood firewall, again, rubber bands were used...

All 3 of these methods worked, but 2 seemed to work the best. This method kept the original downthrust. The reinforcement was 2 triangular pieces of 1/8" ply glued under the existing mount. This brace finally broke when the aircraft thought it would be fun to emulate a lawn dart, and its wing snapped in half... All I heard was a CRACK, a loud "Oh C**P" and 5 seconds later a smash...

At least the radio gear survived...
Jul 06, 2001, 01:58 AM
Registered User
Thanks for the info spam! All good
suggestions. I'm also considering replacing
the plywood arms with carbon fibre 'cept not
having dealt with CF very much, I
have no idea if a strip of carbon would be
suitable or not. I need it to be strong
enough to support the 280 while being able to bend in a mild crash and spring back into shape. I'm not sure what thickness
to get or if I should go for a CF tube.
Are CF tubes available in rectangular cross-
sections? If so, those might be more suitable.