I see this phrase brought up almost any time anyone mentions a CAP of any model...could some one please tell me what is the emfamous CAP snap

Most scale versions of the CAP tend to Snap-roll all on their own when they get slowed down and the nose is raised a little. Can be VERY un-nerving 5-10 feet off the ground, and expensive. Wing tips stall.

I will add that this can be a desirable flight characteristic when performing extreme aerobatics. If the airplane is not flown out of its intended flight envelope there really shouldn't be much problem with unintended snapping.

All the full scale aerobatic airplanes are designed with enough elevator authority to easily stall the wing. They need it to perform the manuevers in their competition. And the models wind up having very much the same flight characteristics.

The Edge, Extra, Ultimate, Pitts, CAP, Sukhoi, etc all will stall easily when you've got the wing at high AOAs. It's their design.

What most modelers do is trim the elevator throw so that there is little excess throw. They often set dual rates such that the low rate is very forgiving on the elevator throw, while the high rate gives just enough more to stall the wing. And then they have full stick movement on low rate with some comfort, knowing that the elevator deflection isn't going to surprise them. And after awhile they've developed the feel for the airplane, and learned the speeds they need to fly to deal with that snappy airplane. And it ain't a snappy airplane no more.

This is not a bad plane design. It is the pilots that don't fly the plane within the design. The Cap is one of the best 3-d planes on the market. Any plane falls is it is too slow. Ask these people and you'll find that very few have even owned a Cap or even flown one. Those of us that have had Caps will tell you to watch the air speed on landing and nothing about it being bad. I see them flown every week-end without a problem. It's always the pilot not the plane. Dennis

Precisely!

My CAP 232 is a snappy little bird (GP Cap 232 kit). It took me a couple crashes to learn how to handle it. It needs to fly fast and land fast to be predictable. I'm not a 3D flyer yet, and haven't tried to set it up as such. My preference is precision pattern flying, and the Cap is a lot of fun for this type flying. If you don't like to make fast approaches, stay away from the CAP!

Brad

A snap roll is when ONE WING STALLS before the other. [ Usually at the tip. ]This produces an unbalanced lift condition and the model rolls very quickly through 90 to 180 degrees.

This is a desireable characteristic if you are a full size competiton / disply piolot but not for a low air time modeller.

Some of the ARTF Caps can be heavy and are prone to doing this on the landing approach and on high G turns.

Been flying my little Kyosho Cap232 for about 7 years now. It is a snappy little bird. Which is to say it is particularly not an honest airplane. Most aerobats are designed to have very honest characteristics, ie a shallow stall which result in a pulse or recoverable momentary loss of authority. Cap's , with a sharper and more swept leading edge tend to stall very deeply and quite easily. Pull just a little too hard in a loop and you are doing snap rolls. Unnerving ! I don't really see it as an advantage as I prefer to do my thing as low as possible. With the Cap, the whole show moves upward about 30 feet. I don't really expect to recover from a snap that low, but at least I have room to relax the elevator when I feel I'm up against the plane's limits.
Now, my Chipmunk, on the other hand is a perfectly "honest" airplane. Its just as capable as the Cap232. But deep stalls are preceeded by skidding and then a shallow stall pulse. You really need to abuse the elevator to induce an accidental snap roll. Recoveries can be made just overhead resulting in level off at eye level with complete confidence. Both planes thrill. But one thrills higher up.

just as I stated. If you know the plane and fly it the right way no problems. Now the question of liking the way it flys or handles is completely different. I've found that the smaller Caps are the more they snap. I've never seen a H-9 33% show bad flying habits. Dennis

I have a 1/4 scale Matt Chapman Cap 232 (73 in wing span) replica by Hanger 9. I fly it with an Evolution GT-35 Gasoline engine. While it does not provide 3D power it flies pretty scale. I have been able to slow this plane quite a bit and not have the infamous "Cap Snap" I will disagree with da Rock in his statement that they are all pretty much the same. I use "digital mixing" for all of my maneuvers. I mix my digits on the two sticks and try to make the plane do something that makes the spectators go OOHH and Ahhh. So I do not use any computer mixing; (read as too stubborn/lazy to read my radio's manual). Thus the Cap 232's knife edge is very difficult for me. The main wing and the horizontal stabilizer are dramatically separated and I believe this causes my hard pull to the belly in knife edge flight. Where as my FuntanaX 100 and Funtana 40, with the mid-wing design putting the main wing and horizontal stabilizer more or less in-line, performs beautiful knife edge flight. So I have my first and last Cap but it has nothing to do with any Snap tendency... Ya know, they say the same thing about P-51's... probably BS too.

They all are not "pretty much the same." All the full scale aerobatic airplanes are designed with enough elevator authority to easily stall the wing. That doesn't result in them all flying "pretty much the same" or even having the same sensitivity to "too much elevator". Sensitivity to the elevator throw also includes how each model has been setup for CG and elevator throw, and how large the tail is and how far back it is from the wing.

You can luck out and place your CG well, and rig the elevator sensibly to begin with and your model will fly better than some earlier aerobatic type. But all the aerobatic types will be able to stall the wing easier than non-competition designs. Will they all do it the same? Nope. Nor will they all fly the same.

A Chipmunk is a perfect example. It's an earlier aerobatic design. It's elevator will stall the wing easier than a Cessna 182's elevator will stall it's wing. Get the CG back and put big movement on the elevator with full TX stick movement and you'll have a nasty flying model. But do some sensible trimming and it'll be easier to fly and lose the nasty.

Best plane I've ever had for aerobatics, building another, is the 1/4 scale Yellow Aircraft Cap 10B . Do a high speed pass and yank the elevator and you'll see the nicest looking, fastest snap you've ever seen. But treat it like a lady and it will do whatever you ask. Will do two Lomcevacs one on top of the other, pivoting around the CG. Most planes won't do one. It has landing flaps, so landings are a piece of cake too.

What he said!

agree, to add the the smaller Caps are critical for weight; the lighter the better.