aileron authority

zero.one.victor · Post by **zero.one.victor** » Wed Mar 30, 2005 1:15 am

While discussing STOP op's on another topic, I mentioned that my ragwing ailerons seem mushy at low speed. I had heard that they are the same as 120/140 ailerons. Well, today I had the chance to measure the ailerons on a 120, and those on my ragwing-- they're identical: 14" wide (chord) and 74" long, the outboard 14" of which tapers down to 10" chord. I calculated out the area at 1,008 square inches.
I also had a chance to measure the ailerons on a 1964 Cessna 150: 12" wide (chord) and 107.5" long, for an area of 1,290 square inches. Wow-- quite an increase in area over mine! Even allowing for the differences in arm (leverage) due to the length & therefore the location on the wing, that much extra area has to provide much more control authority.
I was hoping someone could measure an aileron on their A or B model 170 for comparison.

Eric

Post by **GAHorn** » Wed Mar 30, 2005 2:10 am

My B-model, left aileron is 8'11" long and measures 10" chord at mid point.

3958v · Post by **3958v** » Wed Mar 30, 2005 3:57 am

While you guys are making those kinds of comparisons Look at the tail of a 195 compared to a 170 and I think they are exactly the same. The other thing that you can think about is which plane has more rudder contol in a crosswind an A,B or a 48. Bill K

N170BP · Post by **N170BP** » Wed Mar 30, 2005 6:19 am

Well, not quite... the 195 has the bottom of the rudder
lopped off flush with the top of the tailcone/fuselage (there's
a "stinger" piece much like there is on a 180/185).

That being said, the rudder is very powerful in the 170.
Perhaps rudder authority is "adequate" in the 190/195.
Never flown one, can't say for sure but FWIW, a neighbor
says his 195 has plenty of rudder authority.

Post by **Bruce Fenstermacher** » Wed Mar 30, 2005 1:25 pm

Actually it has been my observation that the 190/195 vertical stabilizer and rudder except the bottom are the same. The horizontal stabilizer and elevator are bigger but the same shape. Maybe that has been an illusion

Dave Clark · Post by **Dave Clark** » Wed Mar 30, 2005 1:58 pm

Interesting on the ailerons Eric. I'd like to fly it someday to see what you're talking about.

The 195 rudder has enough authority but not as strong as the 170. The moment arm to the rudder is larger on the 195 (the tail is longer) and that seems to make a big difference also. Having owned a 195 for ten years the biggest impression is the feeling that you really don't want to let that long tail get very far out of whack on landings. There is a definite feeling that at some point you'd never get it back.

That said the 195 is really a pussycat to land. Everyone should own one for a while. Some say it's the last real airplane Cessna built!

zero.one.victor · Post by **zero.one.victor** » Wed Mar 30, 2005 5:41 pm

gahorn wrote:My B-model, left aileron is 8'11" long and measures 10" chord at mid point.

George, your aileron "measures 10" chord at mid point"-- are you saying that the aileron is chord is tapered? I seem to recall that they're constant chord, except maybe right at the very end.
Anyway, 109" X 10" works out to 1,090 square inches, an increase of 82 sq inches (8.1%) over the ragwing's aileron area. A small but perhaps significent increase. Of course, there's the arm (leverage) factor, maybe this evening when I have some time I'll calc out the moment of the two aileron, that'd give a better idea of effectiveness.

Eric

Post by **GAHorn** » Wed Mar 30, 2005 6:41 pm

Well, I shouldn't have said it like that. My aileron has the same chord all along it's length, but.....it's upper surface is 10" chord and it's lower chord is 12-1/4". (Frise type ailerons.)

3958v · Post by **3958v** » Thu Mar 31, 2005 12:19 am

According to a book I have "Standard Catalog of Cessna Single Engine Aircraft" By Jim Cavanaugh revised by Kim Shields the sizes of the vertical stabilizer and horizontal surfaces are Exactly the same sizes. The book may be wrong but I will measure the next 195 I see. I would not be surprised if the inner construction was different. Bill K

mrpibb · Post by **mrpibb** » Thu Mar 31, 2005 1:44 am

I think the 170A,B model ailerons are the same as the 172's. Erics right about the ragwings 140 ailerons we ain't got what you modern 170's got. Because of such, I limit my crosswind days, on those high croswind days you run out of aileron on a ragwing while your still floating down the runway.
I got a email from micro aero last year, you see I have been bugging them to stc a set of vg's for the ragwing, mainly to gain aileron control at the lower speeds here's a copy of the email.

Hello Vic:

Yes, we have STC approval for VGs on 170A & 170B but not for the C170. Good news is that we have located a 170 here in the State of Washington that the owner will let us use for the FAA STC certification flights. We hope to do those flights next Spring. Meanwhile I have put your name on our list of 170 owners to notify as soon as we get the STC.

Charles at Micro Aero

I wonder if it's a club member? Hmm someones not talking.

Post by **GAHorn** » Thu Mar 31, 2005 3:05 am

If aileron control of a ragwing is less-than-satisfactory to you at the aircraft's present slow-flight capability.....then how can you expect it to be more authoritative at even slower speeds? (I don't think so.)

Post by **Bruce Fenstermacher** » Thu Mar 31, 2005 3:44 am

George what is it that you don't believe about VGs. You don't believe that they cause the boundary layer of air to stick to the wings surface better and at a greater angle of attack which does 2 things. It makes the wing stall at a higher angle of attack and slower speed and it makes the ailerons more effective all the time.

Now I don't want to start another discussion about how much slower you can or can not go with VGs. We are talking aileron effectiveness here.

Post by **GAHorn** » Thu Mar 31, 2005 4:21 am

I don't believe the ragwings aileron problem is boundary air separation. I believe it is lack of surface area, and slowing them down even further will not likely improve the situation. It's only my opinion, not having flown a ragwing in a test-flight program before/after VG installation. If someone can get an inflight video of yarn tufts on the aileron before/after VG's then it'd be a lot more informative/convincing to me than sales brochures, but anecdotes from someone who's spent the money on their own airplane and their subjective opinion of the results does not make for convincing (or reliable) testing. IMHO It's pretty typical that any pilot who spends more than just a few dollars modifying his airplane will praise the effort. It's sort of like asking him how he likes his wife when she's within earshot. At least that's been my experience.
(I even know a British pilot who swore he'd sooner quit the airline than fly a French airplane....until his airline shut down the 727 program and only gave him the Airbus to consider. As he went thru school he continually hated/bad-mouthed the Airbus. Now, after three years flying it, to hear him tell it...it's one of the greatest airplanes ever built. Seems to make no difference they can't keep their rudders and insults the pilot on every auto-land.*)

* Over the numbers the auto-land feature has a voice which comes over the speakers instructing the pilot to retard the throttles. Pilots of other airplanes claim it's actually commenting on the Airbus pilot's mentality when it repeatedly says, "Retard! Retard!"

zero.one.victor · Post by **zero.one.victor** » Thu Mar 31, 2005 7:17 am

gahorn wrote:If aileron control of a ragwing is less-than-satisfactory to you at the aircraft's present slow-flight capability.....then how can you expect it to be more authoritative at even slower speeds? (I don't think so.)

That's kinda my point,George: if the VG's merely make slower flight possible by lowering stall speed without increasing aileron effectiveness, then IMHO they're not really worth the trouble. I already did that by using about 50 cents worth of the handyman's best friend (duct tape) for flap gap seals. If they DO increase aileron authority, then they'd maybe be worth pursuing. That's why I'm asking about VG results.
I wonder who's airplane is the R&D platform for the ragwing VG's? Micro Aero is in Anacortes,about 35 miles from Port Townsend. In the past I'd thought about offering mine, & maybe getting a free set of VG's outa the deal (?), but I figured they'd need it for more than an afternoon so blew off the idea.

Eric

3958v · Post by **3958v** » Thu Mar 31, 2005 10:58 am

I dont really consider the ailerons to be a problem on the 170. I have always been able to get the wing down in a crosswind with a little more speed and you should be able to have more rudder authority in a ragwing without the dorsal fin. Truth of the matter is its all splitting hairs. I have flown a Pacer before and after VGs and unless they are real cheap when they become available I am still going to spend my money on gas. Sometimes airplanes are like women its just best to be happy with what you have!!!!!!!!!! Bill K.