Will this airplane fly?

Think I would have made it a 24" wing span.

You didn't mention the weight. I'll assume it weighs in at 14 ounces or so.

It'll go like a bat out of hell when the engine's running. If it's a "trainer" it's certainly not a primary trainer! If you cut the weight down to 10-12 ounces it may make a good trainer with an .020, however.

For a primary trainer with a Cox .049 reed valve engine I'd go with something that weighs in at about 16 ounces, has a wing area of between

200 and 300 square inches, and a span between 36 and 42 inches.

On Sat, 10 Mar 2007 14:49:59 -0800, I said, "Pick a card, any card" and "Ook" instead replied:

So then you weren't really asking for advice or opinions. You just want affirmation. Fair enough.

Go build it. It will fly.

Feel better?

-- Ray

There are certainly plenty of .049 powered planes with 24" wing and more. I made this one smaller on purpose. I have another plane with a 28" wingspan that is the same style as this plane - it's big brother so to speak. I'm going to put my teedee 049 or 051 on that one.

No no no no no. There are people here with far more knowledge and experience then I. I've stated what I'm doing, and others offer advice and opinions. I read, I learn. I don't always follow their advice, but I still read it and think about it.

This much I know. What I don't know for sure is how well it will fly, because it's been a long time since I've built and flown airplanes, and I've never put an .049 on a plane that is this small and this heavy.

Much :-)

I'm not sure, really. I am making it a bit on the heavy side, it may be as much as 16-18 ounces when I'm done. I'll be sure to weigh it to see exactly what I ended up with, I don't think I could even guess at this point.

And with a wing that small it might have the glide ratio of a brick if it's too heavy. Hmm. I was aiming for less maneuverability, maybe I went too far lol.

Judging from some of your previous posts, I'm assuming that you're talking about a control line plane. Is that right?

For an RC, Tim has the numbers about right. For control line, I don't know.

On Sat, 10 Mar 2007 15:17:09 -0800, "Ook" wrote in :

You can guess a lot about flight characteristics by looking at wing loading.

Except that I've forgotten the units. :o(

OK, Tower Hobbies says it's ounces per square foot:

"Wing Area/Wing Loading: Wing area is the amount of wing surface available to create lift. Wing loading is the weight that a given area of the wing has to lift and is usually measured in ounces per square foot. Generally, a light wing loading is best for beginners. The plane will perform better and be easier to control."

Floaters are under 20 oz. per sq. foot.

Trainers usually are in the 20-25 oz/ft^2.

Nasty, hard-to-fly, scale warbirds are rumored to go

35 oz/ft^2 and up.

Fly it and let us know what happens!

"One observation is worth 10,000 expert opinions."

Marty

Yes, my apologies for not clarifying that. I know, this is models.rc.air - but it's the only newsgroup I've found on the topic that has any traffic, so I hope you don't mind my control line topics.

Oh. You should have said.

That sounds a bit big for a reed valve .049, and way way too heavy. That size, at about 1/4 to 1/2 that weight, with a honkin' .061 may work, though.

If you can get it to weigh in at about 11-12 ounces, it sounds okay. At 16 ounces the wing loading is quite high for a small aircraft. Wing loading is the key element. Wing loadings that work fine on larger aircraft do not translate well to smaller sizes - Reynold's numbers rear their head. You have 0.73 square feet of wing area, I would strongly recommend you aim for

12 ounces all up weight or less, but a little bit more may be okay depending on factors you haven't even told us about yet like airfoil, tail volume, yada yada.

For reference I have an original design R/C sport model with 180 squares that weighs in at 11 ounces ready to go, and it is light and agile and flies like stink. I also have a CG JR Falcon that weighs in at about 20 ounces wet, and flies fine. I think it has a wing loading in the rough area of your project. I wouldn't want it much heavier but it's good where it is.

If this is a C/L aircraft, there is no reason it should weigh more than 8-10 ounces with a wing that size.

I'll be sure to watch the weight. It's up to about 3.75 ounces right now, but it still needs to be covered. Does the weight include engine? The engine weighs about 2 ounces. I need to add elevator, stab, rudder, cover it, paint it. I think I can get it done at about 12 ounces depending on how much weight paint (dope) adds to it.

This pic is the current state, and it weighs in at 5.75 ounces, including engine, fueltank, belcrank and wires.

Hello from a long time CL flyer (40 years or so) from the look and the weight I think you will have a fine flying CL plane. Dont use too much up and down elevator (maybe 30 degrees max) and make sure the balance is fairly far forward for the first few flights (usually small CL models like this can balance about 10 to 20% back from the leading edge. Make sure to put a couple pennys of tipweight in the outboard wing to offset the weght of the lines. If you have other questions drop me a line at snipped-for-privacy@aol.com. Cute plane and it looks like it will fly fine with that high lift airfoil. Just dont try to fly it inverted. Bob Furr

Hi, Bob, thanks for the input :). I loosely patterned it after the old Scientific Zipper, which had a built up wing and fuselage, 19" wing, and flew like a bat of hell. It was very light, and unfortunately flimsy. In the background, you can see a wing on my desk, it has a double airfoil and a 28" wing. I'm going to put a teedee 049/051 on that one and see what it does. In all my years of flying, I've never flown inverted. I'm afraid I'd get confused and splat the thing into the ground :(. For some reason, I'm better at building them I am at flying...