Aileron Stops.

delete

TJ...

That's correct... On any airplane, if there's two sets of stops, the aileron stops are always secondary...

TJ

In advance, sorry for the added confusion !

Funny you should bring this up. I need to re-rigg my airplane (I?m real left wing heavy) and was thinking about doing it this weekend. In preparation, I read through the rigging section of the L21A manual that?s on the Northland disk.

Now, I thought I had a grip on this, until I read this thread, so I went back and re-read that section of the manual. Now I see where it leaves a sorta ?fill in the blanks? scenario. That?s were the confusion comes in.

Here?s what the manual says:

Section II, paragraph 2-75, page 42

?...adjust the aileron stops (24, figure 2-14) until the clearance between the stop bolts and torque tube aileron arm is 3/32-inch when ailerons have reached the limits of their travel.?

If you don?t have the Northland disk, I need to point out that 24, 2-14 is the torque tube stop bolts in the cockpit. Furthermore, the limits of the aileron travel is 18 deg up & down +/- 2 deg

Read that a few more times. What got me was the statement ?limits of their travel?

When I first read it, I ?wanted? it to read ?set the aileron horn stop (on the wing) (85, figure 2-1, page 14) so that the ailerons have 18 degs up & down travel?.
Otherwise, what are they talking about when they reference 3/32" at the stop bolts in the cockpit?

Without complete names, both 24 and 85 are ?aileron stops?

So, if you set the stop bolts on the torque tube at 18 degs, where do you set the aileron horn stops, +/- 2 degs??? And if you don?t set the aileron horn stops at 18 degs with 3/32" at the torque tube bolts, whats to stop the ailerons from ?flappn? in the breeze when you?ve got the stick at full deflection?

Can you imagine all the grunts in the field, looking at the L21 manual and saying UMMM... AHHH...Sarge...???

So in conclusion, sorry about the confusion but, unless I hear otherwise, I?m settn my wing stops at 18 degrees up, 18 degrees down, and puttn 3/32" at the torque tube bolts.

Thought you said aileron travel was 18 deg +/- 2 deg. Why are you setting yours at 14 deg?

You got me! Damn you guys are quick :evil: 18 up 18 down. Thanks for pointing out my SNAFU Longwing, I corrected it. Next rebuttal please.

delete

delete

Tj

Now just a cotton pickn minute. First off, I didn?t start this thing, secondly (and before SJ moves this to rants and raves) who exactly was it that prepared the L21 manual for the military? HUMMM....let me think....do the initials PIPER come to mind? Get over the ?left wing heavy thing already?!

My ruffles are all feathered...I think I need a time out!

OK, here's the theory...

If the ailerons hit the aileron stops (AS) before the torque tube stops (TTS) were reached, you would be able to put excessive strain on the control system from the stick to the aileron... By hitting the TTS first you can't stress the cables, pulleys, hangers, etc...

I meant to say ...?my feathers are all ruffled?...SHIT!!!!!...

And for all you kids out there, please pardon my language, but dang it, I?m really upset. First it was the Teflon tape"thing", now this? I?m calln my support group

I agree with you Dave. That's always been my understanding, that the stops are the bolts near the torque tube. I've always been told, that the stops at the ailerons were primarily there to prevent excessive travel and damaging the ailerons from a gust of wind.
Brian

I?m sinking. I think I?ll just take to my bed.

delete

delete

Thanks for the entertainment last night folks. It gets pretty boring around here with Mrs. Cavy working nights and all. I guess I?ll just set the stops at 18 degs. As for the compass...I got that one all figured out, first thing you need to do is take some Teflon tape and.....

Hey Cavy..........I flew my J-3 around for years without the stops on the ailerons out on the wing. (not recommended) I didn't know they were suppose to be there until one day I saw them on another cub.

What ailerons stops out on the wing. I don't think I have any. I'll look closer this afternoon but would one of you guys send a picture. I may have missed something important when I built my SC.

It ain't over yet. Gonna throw some gas on the fire.

AC65-15A reads.....

"During the checking of control surface travel, ensure that chains, cables, ect., have NOT reached the limit of their travel when the controls are against their respective stops."

I always thought that it was better to have it and not need it, than to need it and not have it. So, I let mine out until they both hit the stops at the same time. It works fine. It would seem that the cables would stretch over time, so it wouldn't be a risk of breaking the cables. Am I missing something?

murph

RMREBOB
This is what we?re talking about.


Click Link Below For the BIG Picture
http://www.supercub.org/albums/Supercubs/bcf.jpg

Sorry about the huge picture, I can?t seem to figure out how to set the stops on it. The one below is easier to look at.

http://www.supercub.org/gallery/view_photo.php?set_albumName=Supercubs&id=bcf

Seems like that answers the question. Just what I've been told all these years and what Cavy has been saying.

My last post may have been a little vage, the contol the AC references is the actual flight control, which should always hit the stop. I have never heard of, or remember seeing any rigging instructions that say that the stop should not make contact.

I can't do that cool quote thing, but Cuby wrote - "On any airplane, if there's two set's of stops, the aileron stops are always secondary." Where does that come from? Never heard it before.

Here is a little clearer explaination from AC65-15A, time to practice typing.

Adjustable and nonadjustable stops (whichever the case requires) are used to limit the throw-range or travel movement of the ailerons, elevator, and rudder. Usually there are two sets of stops for each of the three main control surfaces, one set being localed at the control surface, either in the snubber cylinders or as structural stops, and the other at the cockpit control. Either of these may serve as the actual limit stop. However, THOSE SITUATED AT THE CONTROL SURFACE USUALLY PERFORM THIS FUNCTION. THE OTHER STOPS DO NOT NORMALLY CONTACT EACH OTHER, BUT ARE ADJUSTED TO A DEFINATE CLEARANCE WHEN THE CONTROL SURFACE IS AT THE FULL EXTENT OF IT'S TRAVEL. These work as over-ride stops to prevent stretching of cables and damage to the control system during violent manuvers. When rigging control systems, refer to the applicable maintenance manual for the sequence of steps for adjusting these stops to limit the control surface travel.

I'll add why this is the way to rig Super Cub ailerons later, I'm sick of typing.

SuperCub MD said:

I can't do that cool quote thing, but Cuby wrote - "On any airplane, if there's two set's of stops, the aileron stops are always secondary." Where does that come from? Never heard it before.

Click to expand...

Mark, you caught me on that one... I should have said:

Sec. 43.13 Performance rules (general).

(a) Each person performing maintenance, alteration, or preventive
maintenance on an aircraft, engine, propeller, or appliance shall use the
methods, techniques, and practices prescribed in the current manufacturer's maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, and practices acceptable to the Administrator, except as noted in Sec. 43.16. He shall use the tools, equipment, and test apparatus necessary to assure completion of the work in accordance with accepted industry practices. If special equipment or test apparatus is recommended by the manufacturer involved, he must use that equipment or apparatus or its equivalent acceptable to the Administrator.

What I stated was opinion...

Sorry...

Stops

I've been told by my A&P, IA that the stops should go "clack" at the same time when moving the stick all the way left or right. That is the torque tube stop hitting at same time the aileron horn hits it's stop. I rig for the proper up and down travel with the turn buckles and torque tube stops and the last thing I do is bring in the aileron stop. It seems to me to be the secondary stop. Crash

aileron stops

is there any one that would have a print with the dimensions and materials so that i could build my own stops, or know where i could get or buy one? the ones on the wing.

delete

I was going to get back to this one and forgot..oops.

TJ is right, the key is cable stretch. Rigging all the stops to hit at the same time sounds wonderful, but remember, you are rigging on the ground, with no air loads on the controls. On the ground, there is no load on the cables other than there own tension, but in flight, depending on airspeed, there is considerable, and variable load on the cables when the controls are deflected.

Forget about the torque tube stops for now, in fact, when rerigging, they should be backed out all the way so they do not interfer with the system.

The ailerons (wing) stops should be positioned so that each aileron hits it's up or down stop at the correct max deflection. The cables should be rigged so that each aileron hits this stop at exactly the same time the opposite aileron hits it's corresponding up or down max limit stop with the cables correctly tensioned.

Now the torque tube stops should be brought in so that there is the correct amount of clearance between them and the torque tube when the ailerons are on there stops. This clearance is to compensate for cable stretch when the aircraft is in flight, and insures that the control surface can reach max deflection in flight, (when is really matters). On a Cub, this clearance may vary because there is no set cable tension. If you are one of those who insists your Cub flies better with the cables so sloppy they sag down off the struts, you will need more clearance to achieve the proper control surface deflection in flight. If your tension is set to where I (and most others) like the tension set, the 1/8-3/32 clearance is about right.

Aileron stops

I have a new set of Dakota Cub wings, they came with the stops that mount to the aileron hinge bracket. Contact Mark Ericson at Dakota Cub & I'm sure he would have them available!

Aileron cable tension 40 + - 2 lbs

Elevator cable tension 62 + - 2 lbs

per 1994 PA18 owners manual

I've set the tension to 30 lbs as I was told by someone years ago and that was way to tight. Took a lot of stick force to move it.