DragracerArt

I'm thinking about partially filling my P51 with some of that spraycan foam insulation... Reason being is this...

I'm still a newbie, so the maiden voyage on my plane was made by a buddy of mine last weekend. He was complaining about the lazy nature of the plane and lack of climbing ability. We fiddled around with the wire adjustment at the tail fin, moving it up a hole or two for more response, but the reward was minimal...

Fastforward to last night...

After partially disassembling the plane for routine inspection/maintenance... I took a look at the servo/wire system that controls the rear fin... I noticed there is NO support at all between the servo and turnbuckle. The wire just passes thru empty space in the fuse... When applying very small resistance to the fin, the control wire flexes ALOT. I could see this same problem in a high speed attempt to climb.

What I was thinking of doing was covering the control wire with a piece of plastic tubing (like used in RC car antennas) then partially filling the back half of the plane with spray-foam out of a can... The foam would expand, surrounding and supporting the tube which houses the control wire... This should eliminate any control wire deflection, and probably make the plane WAY more responsive...


Any thoughts ???

AJ1202

If your only concern at this time is the control wire to the elevator you could try this, remove the wire and glue a piece of either CF rod or bamboo skewer between the stretch, I did that to mine and it totaly removed all the flex in the linkage wire. I used CF tube, I cut the wire in the middle and using 5 min epox I glued the wire into the CF tube leaving a very short part of wire out, it's like having a steel rod for linkage with no gain in weight. Others have just glued the rod to the outside using wrapped string and epox method.

ozrcboy

Foam in the tail will also make her tail heavy - you will need to add extra weight to the nose to keep her balanced - and we all hate adding weight.

DragracerArt

Any idea where the center of gravity is supposed to be on this plane ? I remember reading it somewhere, but can't remember where.

ozrcboy

Rule of thumb is 30% of the distance from leading edge to trailing edge measured against the fuselage. However, you could also just assemble the plane in strock trim, figure out where the CoG is, mark it, and then use that as a reference after you have done any modifications.