cabpond

Hi All !!! Please help

I'm building a plane by the "seat of my pants" so to speak.

The fuse is 40" long with a 60" wingspan 15" chord at root, 11" at wingtip with 3 1/2" dihedral. It it a low wing plane, built pretty much like the Demon, only with the longer fuse-wing and dihedral built in. I'm using a OS 91 FX for an engine.

The problem I'm having is that with the engine installed with the Hayes 12 oz. fuel tank (6" long), the wing has to be mounted approximately 7" back from the front of the fuse, which leaves the plane WAY nose heavy when balanced on the spar (1 1/2" lattice spar at roughly 75% of chord-constant). I tried moving the battery as far aft as possble, but is still nose heavy on the spar.

Should I :

1. Cut another fuse, making slightly longer to give extra weight
on the aft section (presently she weights 8.5 lb).

2. Add weight to the tail of the plane (don't like the idea).

3. Try and not "re-invent the wheel" and be happy with the
SPADs presently available.

The plane I'm trying to create is the Demon airplane, Slightly larger, with dihedral and a bigger engine up front.

Too much time on my hands.

Thanks Cary

grant-RCU

My Feedback: (10)

Since its a low wing just rubber band the tank on top of the fuse.

I wouldnt make the fuse any longer. you dont want the extra weight.

cabpond

Grant:

Thought of that, Would like to keep everything inside the fuelsalage if at all possible, but if not, that may be my only option.

Thanks for the reply and the idea

Cary

stdun

I have that problem with nearly every spad I build, which is all sizes and types. I use OS fx motors also and that seems to be part of the problem since they are heavy-ish. Mount the motor as far back in the mount as you can, mount the wing as far forward as you can and if that doesn't do the job I add the smallest amount of weight as far back on the tail as possible. Sometimes an ounce or two at the very rear does the trick. With a .91 size motor you shouldn't notice a little extra weight.

cabpond

Studan:

Thanks for the reply and the suggestions.

I have , since finding out the plane was severly nose heavy, moved the engine as far back on the motor mount as possible,

I will re-balance the plane. This should make some difference, since I was able to move it back 1", and as you suggested, might add an ounce or two to the tail to get it to balance.

Thanks again for the suggestions.

*Isn't this fun !!!

Cary

Woodsy

what you need to use is the SPAD (pat pend) wire wing hold down clip.
basicaly bend a bit of wire or ally strap in a U to fit the fuzz with a little turn back on each end to form a hook. wallah problem solved.

or just CA a bit of dowl on the opposite side of the fuzz from the wing.

i'm sure some one will post a pick of what i mean

grant-RCU

My Feedback: (10)

so is the spar getting in the way of the tank in the fuse? or is it the dowels? if its the dowels do like Woodsy suggested.
This may work also but I am not sure. I would think if you put the tank right behind the spar it would not effect the cg that much sine it will be right at it. You could also leave the plane a tad nose heavy to compensate for the fuel in the tank. you probably wont be running the tank dry any way. It will take some experimenting to get it just right but it think it just might work.

stdun

Woodsy, could you elaborate on the wing hold down clip? That sounds like a real problem solver. Mabye a pic? Thanks.

Woodsy

heres a pic of one of Tattoo's planes, theres more info on the www.spadtothebone.com tricks and tips page under build info/wing hold down

ChrisSpad

http://mywebpages.comcast.net/TipsTr...ng_holders.htm

Crash Master

Would mounting the elevator and rudder servos to the rear of the fuse give you any more tail weight to help balance it?

Just a thought,

grant-RCU

My Feedback: (10)

yep it sure will. that moves about 3.4 ounces of weight to the rear. I always mount my servos near the back. my hs 425s weight 1.7oz a peice