Wing area
 

I am a newbie here so can someone tell me What is the difference in wing area when one is 1025 sq/in and the other is 893 sq/in what does the airplane do I am looking at two models an I want to use a 30cc gas engine and they also say wing loading

Lets say you are buying an airplane, one has 1025 sq.in. of wing area, the other has 893 sq in of wing area. Now lets say they both weigh 10 lbs. = 160 ozs. The airplane with 1025 will have a loading of around 22.5 ozs. but the airplane with 893 will have a loading of around 26 ozs. In my opinion lighter loading is better, so I always buy or build to the lower wing loading. Keep in mind that is just my own opinion and there are lots of argument about that on RCU. I hope I have answered your question.

Bob

Expanding on sensei's comments the plane with lower wing loading will take off sooner, fly more slowly and land more slowly.

To continue expanding.....everything else being equal, the plane with the lighter wing loading will be easier to fly and more suitable for a newbie.

"And further more".......Everything else is NEVER equal !! So, just the wing loading will not tell the entire story. It will be an indication, a factor, but not an absolute. If both are models of the same full size aircraft ( or if they are not scale models say they are both Sig Kadet Seniors or whatever) then the lighter wing loading will be the better (easier) flyer. However, if one is a P-51 Mustang and the other is a Kadet Senior, the kadet will still be the easier flyer. STYLE matters. What style aircraft are you comparing? Exactly what two models are you looking at? What aircraft have you flown and feel comfortable with? If they take a 30cc gas engine, they must be a good sized serious model, not normally a newbie plane (you said your were a newbie). Tell us more details please.

they are both 342 Sbach one is a 73" wing and the other is a 65.5" wing but they both weight 10lb

Ok, they are both models of the same plane, at the same flying weight so the 73" wing span with the larger 1025 sq.in. wing area will have the lighter wing loading and be the easier flyer. That's the one you want !

My quick calculations show the 73" plane to have a wing loading of 22.50 and the 65.5" plane to have a wing loading of 25.80. Do you under stand how to figure out the wing loading?

Oh, now I see that sensie already figured out the wing loading of both planes in post #2. At least we both got the same answer.:)

You are looking at 3-D capable type airframes, lighter loading=better 3-D if that is what you seek.

Bob

For a 30cc motor, go with the 73"

I'd go with the bigger plane as well - BUT - that's me! If you were looking for better wind penetration or a plane that's more sport than 3D, you might want to consider the smaller plane.

Honestly though, the 10 lb weight for a 30cc plane sounds pretty optimistic, unless the plane has been designed from the get go for 3D. This could translate into a very lightly built airframe that's not going to be very forgiving of abuse of any type. That aside, the plane should be very capable of anything you'd ever want a 3D plane to do.

Now I have another question the 65/5" airplane calls for a 1.20 I have a thunder tiger 1.20 with a Pitts muffler and I have a 30cc gas engine that weights 20g lighter could I used the 30cc instead or would I get into trouble

Converted to gas exclusively here a while back, so I'd sell the 1.20 and buy a 20cc DLE or maybe RCGF, and use that...

Either 20 in a sub 10lb plane would give you unlimited vertical. The 30 would be 8oz heavier, and have power you could only use if pointed straight up...

When comparing the weights, don't forget to include the muffler, ignition module and battery. The published weight of most gas engines does not include those. Also, the 120 size airplane may not have the ground clearance to swing the bigger prop that the 30cc will need.

the TT engine with Pitts muffler and mounting bracket weights 1435g the 30cc with Pitts muffler and all the electric weights 1356g

Not questioning your measurements, but at 3.15 pounds, that TT 1.20 is way heavy! For comparison, the OS 1.20 AX, with muffler, weighs 823g (1.81 pounds).

I guess you could use either one of your engines, but I would surely stick with the larger airplane. If the smaller one is designed for a normal 1.20 it might have a hard time carrying that super heavy TT.

We're all still wondering who the manufacturer is so help could be more accurate. Got any links?

Who manufactures the planes. More info you give the better you get helped.
Got links to the planes?

Here is a link to the airplane in question

http://www3.towerhobbies.com/cgi-bin...?&I=LXEKBF&P=7

Like I said, 10lbs with a 30 pretty optimistic. With this plane, 10lbs with a 20cc pretty optimistic........

The specs for that airplane give a weight of 10.4 to 11.4 pounds and a wing loading of 27.85 oz/sq ft. using an engine that is 1.4 pounds lighter than yours. The weight with either one of your engines would be 11.8 to 12.8 pounds and the wing loading would be 31.5 oz/sq ft.

At that weight and wing loading, 3D would be totally impossible, the airplane would takeoff, fly and land all at the same high speed and tip stalling would be very likely.

Have fun,
Jim

Gee, I thought weight was the only thing that mattered in 3D since the plane never really flies - it is just pulled around by a honkiing huge engine.

Sorry, I don't like 3D - it isn't flying.

I am strickly a sport flyer don't do 3D

Ignorance is truly bliss... Weight matters on war birds, civilian birds, and aerobatic birds including 3-D capable birds, the lighter the loading the better the airplane will stay on the wing or get back on the wing at low airspeeds without tip stalling the minute you raise the nose with the elevator. HP has little to do with staying on the wing of a truly light wing loaded airplane... If you think hanging on the prop is 3-D flying, think again.

Bob