Gary496

I,m really confused as to what , 4s will fit into what.. If you look at specs. on 2 different kit/ARFs, both with similar square in. of wing , same wing span +/- an in., Weight within 1 lb. of each other, yet one plane will take up to a .91 4s and the other will only take up to .52 4s. I realize we have a tendency to over power but, sometimes MFG spec. bewilder me. I got on the thread to Great Planes and asked if a 80 4s would be to much for a Rapture and they replied a 52 4s was the max.. Yet the max. 2s was .50. I thought the conversion from 2s to 4s was a wider difference. How does one make a decision? I want to put my new Mag. 80 into something, sport type as I am a newly soloed flyer and I already have 2 Tigers, 40 & 60 size. Someone said the 80 would be perfect in av Astro Hog Bipe, but I'm not sure I'm ready for that.... Advice anyone ?

TomCrump

Hey Gary !!!

Why don't you put that 80 in an Astro Hog? You know, like Todd's.

If you run into any constuction problems, I know a couple guys that might help you out.

cms108

what i tend to do is completely ignore the manufacturers recomendations (what would they know?) and completely build the plane as much as possible without an engine. then balance the plane with some lead weight in place of the engine and see how much weight it takes to balance propperly. then you know what size engine to go for.... you don't need to use all the power, but it's there if you need it... and you're not going to be adding much weight to either the nose or the tail.

manufacturers tend to be a bit conservative with their engine recomendations so that people don't go ripping the wings off, not because of what will actually fit in the plane.

--
cHris

DBCherry

My Feedback: (4)

A lot depends on the type of plane too. An 80" wingspan Piper Cub will fly okay with a 52 four stroke, but an 80" Extra? Ain't gonna fly worth crap IF it gets off the ground.

I generally go with the high end of the manufacturer's advice, depending on the plane. I might go over on an aerobatic plane.
Dennis-

MinnFlyer

My Feedback: (4)

An 80 is a rather odd size engine, but I think a Rapture could handle it.

Rcpilot

My Feedback: (78)

If your flying at high altitude- then the manufacturers specs go right out the window.

I have flown in Denver at 5973' for about 6 years and we put a MINIMUM .46 on a Sig LT-40 or a Kadet Senior. Better off to go with a .60 on the LT-40 and a .91 4 stroke on the Senior if you want any power at all.

My World Models 80" Patty Wagstaff Extra weighs 16 pounds with a G-62 on it and it won't hover in Denver. You follow the manufacturers recs on the engine on this plane-- and you stick a puney OS 1.60 on it-- and you better have a 2000' runway and plan on flying flat and level-- no loops or snaps-- and fly it in at 1/2 power for a landing.

Just recently moved up to higher ground and will be flying at 2 different sites. One at 8500' and the lake here is 10,175' above sea level. I'll be flying a "slightly" modified LT-40 with floats and a TH .75 2 stroke at the lake when it freezes up.

If you want to hover in Denver at 6000' then you need an engine 2.5--3 times bigger than the MAX recommended by the manuf. I had a Chief Aircraft Giles 3D 40 size with my TH .75 on it and it would hover at 1/2--5/8 throttle and it weighed 5.25 pounds dry. Ripped the firewall out after about 100 flights[]. Should have glassed and pinned it.

I agree with the lead theory. Build it and add lead to the firewall untill it balances. Buy an engine that weighs that much and give it hell. Remember, the left stick DOES go up and down. You don't have to run it full throttle all the time.

There's no such thing as too much power-- but; a greedy left thumb will kill you everytime You can fly around at 1/4 throttle or even 1/3 throttle. Just use that left stick for big vertical maneuvers or hovering.

Gary496

Hey rcpilot.. thanks for all the info,however I'm in Michgan at about 600' above sea level. I'm not sure how your info relates.