It is for the 737 and 727 elevator and ailerons, as I remember. Later Boeing airplanes don't have manual reversion. The last couple don't even have cables to speak of.
I only flew 737 100 and 200. They were almost same.
Not the issue.
I was wondering about a tab in a fixed position, just would it act in the trim tab function or control tab function. After thinking about it, I knew the answer did not matter. In a CL stunter the pilot is flying negative "G" as much as positive "G" therefore a set tab would be detrimental to the flight pattern.
If your wing is really, really flexible, ...
It is NOT!
That's one reason the outer ailerons of the 727 get locked out at high speed.
Close Howard but no cigar!
The outer 727 ailerons came into full play as landing flap
selections were made. That was in normal operations 30 and 40 degree positions. Engine out position was 15 and certain control problems were position 15 or 25, but that was irregular operations.
At Flaps 5, the outer ailerons had 80% movement. At flaps 2, the outer ailerons were closed. In all cases the outboard tabs served as balance tabs, to reduce control loads.
It's been a very long time since I last set the parking brake on a 727, however about 70% of my almost 20,000 hours was in the most fantastic airplane ever built, truly THE LAST OF THE SPADS!
If you use the tab to compensate for a warp in the wing, your stunter will suck,for reasons explained here before.
Yep, I forgot that the negative G would really upset the apple cart.
One one funny about trim tabs: The old USAF T-33 was the plane I did my last 6 mo. in training. I never learned this then. When I went back as an instructor it came into play.
The T-33, originally an extended nose of the F-80, was very nose heavy. When they took the guns out, it was set up with nose weights to compensate.
It was a tad overdone, and the trim tabs on the elevator were very small, but very effective through most of the flight envelope.
On landing the relatively small stabilizer did not have enough surface with full up trim (tab rolled down) to hold up the nose for a smooth greaser unless you were 10 knots or so fast., for the weight.
To increase the effectiveness of the elevator we learned that by rolling in full down-trim, tab goes full up, it was much easier to get a grease job, and impress the student!!! HA! It took both hands on the stick as that elevator became FULLY LOADED Big Time, but it worked.
To Dick: It's been almost 40 years since I built and flew stunters. A Ringmaster and Still Stuka maybe 20 flights total in all these years but no real stuff. Looking forward to it.
This new one soon to get into a finishing stage (to me finish means it's finished - I hate sandpaper and it use
) has adjustable flaps. The pusrod off the bellcrank connects to a horn soldered to a torsion bar, in an aluminum tube, going out about 8" each side, bent straight down out of the wing, with simple connectors/pusrods to the flap horns on the bottom of each flap. Just like an aileron set up for RC. Totally able to set each flap as desired.
Well I gotta' get to work on it.
BTW Rush, my flying will "suck" and my airplane may well do same. However I am doing what I WANT to do, and not rushing behind how, what, and why, some great person that is really good at what he/she does, and I just play copy-cat or hang on to what is being done by others.
Not my style.
Topic: Trim tab vice control tab aerodynamics. (Read 1849 times)