i just got a .46 size edge 540 from seagull hobbies.
i plan to put a gms 76 in it with a 14/4w apc prop.
its same wieght as the saito 72 and os 70 fs give or take an ounce.

my quess is that the top of the motor box is open, should this area be strenthened or not.
usually its enclosed or a piece is provided to cap it off.??

also want to know if the gear needs help too,due to the added wieght up front.

all this while keepin at around 6 lbs lol

any help is great
thanx

Ah... according to the Tower website, the GMS 76 weighs just about 24 ounces with the muffler. the OS 70 weighs 18.3 ounces and the Saito 72 is lighter. You are also going to need 3 ounces of tail weight to balance that extra 6 ounces up front. Let's be charitable and say that the 76 is going to make that Edge half a pound heavier than the 70 or 72.

If that doesn't bother you, go for it. It would bother me, though.

Jim

thanx jrf,

on this site is where i saw the comparison of the os fs 70 and the gms 76 were both 20.10 oz.
the saito is considerably lighter 16.56 i think.
unless the 76 number was with out muff.

so u wouldnt put this engine on this plane?

Tower knows what they are talking about. They are a branch of the importer of both OS and GMS. The GMS 76 is 19.4 ounces without the muffler. A 60-76 size muffler will weigh 4 to 6 ounces. That puts it right in the ballpark, most 61 and 75/76 2-strokes with muffler, weigh right at 24 ounces.

No, I wouldn't add that much weight to a 40 size airplane. It would make it really twitchy. I'd use an OS 55 or a Saito 82. Either one of those will give it better overall performance than the 76.

Jim

thnx for the info jim,

if i had the extra money to buy a new engine i would have went with the 82.

i just finished it and wieghed it dry and came out at 6.4722 lbs on the digital scale all up.ended up puttin a bisson pitts on it.

had a time getting the cg right though(shocker)lol.

luckily it was just a matter of relocating the batt to the rear of the servo tray instead of right behind the tank.

full it ll be a little nosey but empty its right on.

i ll let u know how it ripps lol.

At that weight you should be fine. Seagull has a reputation for being a little optimistic on their weight claims. I expected it to come out heavier. Your wing loading is around 23 oz/sq. ft. That is too high for 3D with a 40 size, but perfect for sport flying. Let us know how it flies.

Jim

i will do that jim.this engine still might be to much

if so i ll be puttin a saito or os in it. 4 st that is.

should i cap the top of the motor box for strength?never saw a motor box with no top.

also was thinkin of givin the inner wood on the gear mount a light skim of 30 min epox.

again lookin to save weight here.


thnx again

mike

Yes, I would cap the engine box. Get some "Finishing Resin" or "Finish Cure Epoxy". It is a thinner epoxy that you can paint on. Works just as well for reinforcing and weighs half as much.

Jim

thanx jim

i though soo too.

i will do that.seems i need a new servo.

least i found out on the ground lol.[:-]

thanx again

mike