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ccurrie
02-18-2009, 10:34 PM
I am new to this site and cant find a place to search the forum, my question is. I have seen a few cubs with alerons that droop with the flaps. Is there a kit to do this like the robertson STOL for the cessna? All the cubs I've see with it were experimental so Im guessing its not STCed .

Fortysix12
02-18-2009, 11:01 PM
Try a search

"aileron droop systems"

mvivion
02-19-2009, 07:39 AM
It's stc'd by Cub Crafters. Varying opinions on it's worth and wisdom. Unfortunately, when the stc'd it, they made no provision to permit disconnecting the aileron droop from flap deflection. With that, and some other mods, it might be a good mod. As CC got it approved, I don't like it.

MTV

Steve Pierce
02-19-2009, 07:58 AM
Cub Crafters no longer sells it as far as I know. There is a search button in the upper right corner that can take you to some good threads on the subject. There is a very good experimental version that allows you to turn it on and off in a crosswind which is where the aileron effectiveness is lacking and needed. Welcome to the site.

pzinck
02-19-2009, 09:59 AM
There was a gentleman in canada that had several cubcrafter droop kits at one time. I think they had traded him for parts when they got rid of them. If interested i would try to get in touch with him and see if he has any for sale.

Dave Calkins
02-19-2009, 11:44 AM
Not all droop aileron systems are the same and some DO work well in a crosswind.

When Steve Pierce talks, people listen. Steve, note my above statement.

Steve Pierce
02-19-2009, 01:18 PM
Dave, I was referring to the CC version with the lack of aileron effectiveness in crosswinds. This has been told to me by a few people that have flown it. I have not. I know Jerry burr has a system that can be turned on and off and seems to work well. Is that what you used in the 12 you built?

Dave Calkins
02-19-2009, 10:56 PM
Steve, thanks for the clarification.

The system I designed for the -12 uses the same principle as Jerry Burr's system (take up on the balance cable/give on the direct cables) but the execution is very different as the -12 has a -12 aileron system. When I do it again I'll simplify it greatly. What makes it work so well is that I introduced a lot of differential into the system by changing the geometry of the -12 aileron belcranks. When full flaps is commanded with flaperon selected, moving the control stick over to one side will not increase the down aileron/flaperon, and the 'up' flaperon/aileron actually goes up above neutral. Also, I have a roll spoiler interrupting lift on the 'up' aileron side in the last 1/3rd of stick throw. It works very well............I lucked-out again!

At first I would remove 'flaperon' for landings and especially crosswinds. Now I leave 20 degrees of flaperon droop selected, and actuate it when I command 'flaps' for maneuvering or landing, even in crosswinds.

Anyway, I mention this all in order that everyone in the world reading this doesn't ascribe to a blanket statement like we so often hear on weblogs. Mauleguy Greg had called droopy's a 'crutch' in another thread, and I'm sure guys everywhere are repeating it, so I'm a bit sensitive.

Thanks again for your clarification, Steve. You're a class act and folks listen to you and enjoy your advice. DAVE

Wayne Mackey
02-20-2009, 08:03 PM
The first cub I put slats on had CC droop system on the ailerons and they work fine. The plane has years of use and hundreds of hours on it and no problems that I know of.* I have flown it and been very comfortable with the system. But I do think Dave has the right idea with the differential
system he uses. My next personal plane will have something close to
it. Wayne

Mauleguy
02-20-2009, 10:39 PM
Dave, I would definitely be interested in a system that could be used in all conditions i.e. turbulent air, crosswind landings. Do you have a system that will work on a stock PA-18 wing.

Greg

Dave Calkins
02-21-2009, 01:38 AM
Greg, I am looking at how to make a system with differential go on an -18 control system.

I've been looking at doing a -12 control system on an exp -18 because it's simple to do the differential belcrank.

I need to get my head wrapped around this and make a decision, as that's what is holding up my personal exp. -18 project right now.

BC-12
02-28-2009, 06:40 PM
If a person just changed the stops so the bell crank had more up aileron authority would this get the aileron up enough to help in slow flight with the droop selected at full? Would it be dangerous to have more up aileron then stock for normal flight without droop. I am wondering if it would easily cause a roll if too much aileron was given, or could it cause the aileron section of the wing to stall? Obviously I have no idea the effects and wonder if anyone has tried it?
Thanks,
Rhett

Dave Calkins
02-28-2009, 11:45 PM
If a person just changed the stops so the bell crank had more up aileron authority would this get the aileron up enough to help in slow flight with the droop selected at full? Rhett
It would take more than just changing the stops. The rest of the problem is the 'down' aileron and the adverse yaw it creates.


Would it be dangerous to have more up aileron then stock for normal flight without droop. I am wondering if it would easily cause a roll if too much aileron was given, or could it cause the aileron section of the wing to stall? Obviously I have no idea the effects and wonder if anyone has tried it Do you mean flying around in cruise with both ailerons tipped up? I'm not sure that's a good way to go.

If, however, you mean 'differential' (more up aileron than down aileron for 'normal', undrooped flight), I have tried it. In cruise, the aileron travel on the 'Custom Cruiser' is about 36 degrees 'up' aileron and about 20 degrees down 'aileron' with full roll commanded. It is no problem at all. In fact, it works wonderfully, another positive (lucky) outcome to an experiment :D

DAVE

skywagon8a
03-01-2009, 09:33 AM
If a person just changed the stops so the bell crank had more up aileron authority would this get the aileron up enough to help in slow flight with the droop selected at full?

The problem is in a strong crosswind landing. With less up aileron available you have less down force on the wing to hold it down into the wind.

Changing the up stops won't help as it is the neutral point that is moved downward. The total travel remains unchanged.

I rigged the electrical powered droop system on my 185 so that I could experiment with different neutrals in flight. I found that in any position other than Cessna's neutral, whether up or down, by any amount, the cruise speed suffered.

It would be an extremely complicated mechanism that would allow a droop with out sacrificing up travel. I doubt that you could get enough extra stick throw in the cockpit, unless you could extend the bell crank below the torque tube further. This would require moving the stringer on the belly lower to maintain clearance. This would reduce stick travel (make the ailerons more sensitive) and increase stick force. Maybe that is not a bad idea?

The Helio has a spoiler (interceptor) ahead of the aileron for cross wind assistance at low speeds. Maybe something along those lines would work? It could be rigged to work all of the time not just during droop operation, thereby making it a little less complicated.

Just some thoughts.

Dave Calkins
03-01-2009, 03:52 PM
skywagon8A, please tell us more about your electrically operated droop system.

Thanks. DAVE

skywagon8a
03-01-2009, 07:03 PM
Dave- My drooping system is essentially the same as a Robertson except that there is no connection to the flap system. The aileron bell crank is changed to a three piece unit with a center movable arm which when moved in relation to the other two parts changes the neutral point that the aileron push rod attaches to. This arm is connected with a 6" push rod forward to a direction changing bell crank then with a longer push rod to a bell crank/cable quadrant which is controlled by a 172 flap actuator drive which is mounted just outboard of the left fuel tank. The quadrant is connected via two cables through the fuselage to identical linkage in the right wing. There are micro switches which limit travel. Control is by a momentary SPDT switch on the yoke. There is also a micro switch on the flaps which automatically powers the ailerons up when the flaps are not extended.

This is approved under STC SA1148SW.

This type of system should work on any airplane that has a bell crank in the wing that moves the ailerons.

I do not have any pictures. I hope that this helps you. If not , I will try to make it clearer.

Dave Calkins
03-02-2009, 02:06 AM
Thanks.

I'll check into the STC.

Do you have any info on the STC? Is it still available, etc.?

Thanks again. DAVE

skywagon8a
03-02-2009, 08:31 AM
Dave - I purchased the rights to use the STC on my airplane from Galen Means in 1982. At the time he was retired and I suspect, that by now, he has gone west. I had a difficult time locating him then and it took a few calls before he felt that I was serious. I was considering putting the kit into production but decided that I could not be competitive with the Robertson and dropped the idea. He sold me permission to use two different drooping designs on one airplane. The other one used a gear arraignment connected to the flaps. That one appears to be associated with Wren Aircraft in Ft. Worth. The SA1148SW has Aerostol, Co., Ft. Worth on the drawings. It also mentions the 172.
If you like I will PM his address in 1982.

BC-12
03-02-2009, 11:19 PM
Thanks