I am relatively new to control line, and have a question.  Why use flaps? My modified Ringmaster can do ten loops in the time my Chipmunk can barely execute one.  My scratchbuilt design, same story. No flaps and flies great. I intend to build a Thunderbird and a Smoothie, but if the performance is the same as the Banshee or Chipmunk, I will be afraid to fly them. Both my brother and I have had great results with the Super Tigre 51 in the non-flapped planes, but are not doing something right with the flap-type planes. Can somebody explain the principle of flapping to me? Thanks

Coupled flaps were added when additional maneuvers were added, and more fuel had to be added as well.  The older spark ignition engines ran on "white" gasoline, which allows far better fuel mileage than methanol does. 

The planes got heavier, and lines longer than about 68 feet turned out not to work well, so the aerobatics planes ended up flying more slowly.  Back when "Stunt" was a combination of speed and daredevil antics, in 1946 and 1947, fast flying was common.  By 1949, it was no longer the norm, although by today's standards, most aerobatic flying was still performed at a fast clip.  The wing flaps helped tighten the sizes of turns that no longer seemed nice enough at the old planes' larger radiuses. 

Initially, the planes' tail moments were rather short, and the flaps created as many problems as they solved.  Early attempts tended to work better if the wing flaps deflected to a proportionally smaller degree, along the lines of 15 degrees to the 45 degrees that the elevators deflected (and be sure to understand that the flaps go DOWN when the Elevators go up, and vice versa).  Eventually, we discovered that the joint between the wing and flaps needed to be closed, as did the stab to elevator joint. 

An aerobatics pioneer named George Aldrich serendipitously hit on a very usable formula of plane size, engine run, flaps to elevators relationships, etc. and named it the Nobler.  Many Noblers were flown with the flaps and elevators deflecting at a 1 to 1 ratio, instead of 3 to 1.  George also slowed his plane down further, from the 70 mph speeds then common, down to the 55- 60 mph speed zone.  The sounds his engines made while in flight caught some fellow competitors unawares.  He set them so that they were skipping every other beat while flying level, but would rev up automatically into a two stroke the moment he applied control. 

That was the "classic" breaking engine run (4-2-4) that became the standard quickly, and remained standard for twenty years or more.  You have now had far more of a history lesson than you bargained for.  Sorry about that. 

In some ways, for the simpler maneuvers, with simpler models, the pre-1951 aerobatic speeds of 65 - 70 mph are somewhat easier to deal with, but when you begin to string together four loops across almost a 45 degree arc of the circle to make a cloverleaf shape, you'll be much happier flying at 60 mph and less. 

 

Thanks, y'all that is some real info. I moved the engine back on my Chipmunk in an attempt make it rotate more, may have helped slightly. I am using  plastic hinges, but the flaps and elevator are as close as possible and not bind up. This plane looks and handles great, as long as I am prepared to abort any loop and convert to an eight. Otherwise I will have a red white and blue plow. I located the engine back a little on my modified Ringmaster when I built it, to compensate for a little different spar design, greater wingspan, and slightly fuller fuselage, but retaining the total Ringmaster look and feel. We always mount our six ounce clunk tanks on the opposite side from the engine for balance and a  visual  on fuel while in flight. Is there a reason this is not common? I also built up the landing gear, brazing together a four piece span on each side, giving a much stiffer, wider, better looking, yet slightly forgiving set-up. Because of the roughness of the field where we fly we also use three inch wheels on most everything. It does give them a "bush plane" look. On the Ringmaster I opted for thinner 2 1/2 wheels for the more classic look. From the pics i've seen of other planes, this is a departure from the norm also. Does everybody else fly on more pristine fields? Our feild is donated unofficially be the city and we maintain it. It is getting better, I must have removed a million rocks and half that many briars.
On the Chipmunk I simply made the gear heavier and longer and slanted a little more for the spring effect and rearward weight shift. The balance is about where the spars meets fuselage, maybe a little back from that to compensate for the sweep of the wing. It looks like my flying style is going to force me to stay away from flapped planes entirely. I am using 70 ft cables with laps at or under 4 seconds. I figure about  107 mph for the Chipmunk with fat wings and and a little more from the Ringmaster. I have not tried a cloverleaf, but I am sure the Ringmaster can execute them no problem.     I am a sponge for info, it cannot be too long winded. It looks like we fly outside the box a little, but when my brother releases my plane after a thumbs up, I am transported to a different reality.    Thanks for the tips on this and the open forum. I responded yesterday but I think I sent it to the Twilight Zone. Fred Shattuck

I definately have them working right, and no need to apologize. When the elevator is at 45 degrees down the flaps are at about 30 degrees up, eyeballing it. I knew Ed Alexander in Ft Worth, Of OVER EASY fame, and he was the one that planted it in my head that flaps are better, with my drooling over his old Thunderbird. He also insisted, and I have always resisted, the 2 cycle, 4 cycle concept of tuning the engine. We run a little on the lean side for consistant rpm at any angle.  Do you think a shorter span between wings would help the roation problem? Thanks.        FRED

Should we suggest a "Wow" repro kit matched to an OS Max 32 SX, perhaps?  That might provide a sufficient thrill, since I rather doubt the 100 mph speeds mentioned this far, and that combo would most certainly do that kind of performance in actuality.