Scratch building an EPP DSer. Got a few Q's
 

I've just finished cutting my cores and my TE are drying as we speak (or type).

It's a 60" plank wing using an MH45 airfoil and it looks like a Hershey bar right now. I've also made a little fuse to put the receiver, battery and vertical fin in as well.

Since this is a constant LE and TE rectangle, where do you think the CG should be? Logic tells me that 20-25% of the chord would be a good start as I base this on the Nitro powered combat wings that I've scratch built.

However, I've read planes such as the M60 can see a bunch more tail weight than seems logical.

I plan on using Ultracote to cover it, burying the elevon servos and fabbing a couple cute little fairings to cover the linkage and make it a bit slicker.

For DSing I've seen some planes get kinda heavy (like 3-5lbs). Can anyone clue me in to why so much ballast is needed? And, do I put it on the CG for the best results?

Thanks for the help. NAES

RE: Scratch building an EPP DSer. Got a few Q's
 

Not sure on the cg thing, although I have flown wings too and that does not sound like a bad starting point.


I think the amount of ballast you need is dependent on many factors and does not need to be perfect unless you are trying to break records. Wind speed would be the primary factor. Adding ballast causes the plane to fly faster at a given glide angle. It will also increase its sink rate. If you over ballast, then you will not be able to stay up easily. If you under ballast, you may have a wind penetration issue ( I doubt this on a real slope machine though).