Closed loop ailerons

[Richard Wicker]

Hi people.

When building a WW1 type with scale wing section, is there a fool proof way of rigging up a closed loop system (or a dummy one) without having an unsightly push rod showing under the wing to the control horn?

Richard.

[Former Member]

[This posting has been removed]

[Tony Patman]

In David Boddington's book there is a diagram of a hidden aileron mechanism which I think is different from Eric's suggestion as I don't think it involves sliders. A hinge is fixed in the leading edge of the aileron at an angle off the plane of the aileron. A rod is attached to the other flap of the hinge, which protrudes inside the wing. As the rod is moved side-to-side, the aileron, by virtue of the angle at which the hinge is fixed, pivots up and down. The rod can therefore be actuated by a push-rod at right angles to it down the wing, either from a central servo or from a dedicated one closer to save a long rod run. I suppose you'd use a ball-link to connect them, as I think the rod attached to the hinge would need to pivot relative to the main push-rod.  Anyway, the mechanism shouldn't be any fatter than the aileron itself, and can be concealed entirely within the wing without the need for any horns or push-rods protruding outside.

It was a challenge to figure out the spacial transformations involved. After a period of waving my hands around in strange configurations, I kind-of succeeded in visualising the motion, but I have a vague intention to build a mock-up at some point just to see how it works before trying it in a model. If anyone beats me to this, or has an implementation already, I'd be interested to see some pictures.

[Evan Pimm]

Or else you could just use cables from the servo hidden in the wing, these cables exiting the wing in the scale position and operating the aileron in the usual 'pull-pull' fashion...bit like a rudder on its side, if you get the drift...

Evan. 

[Bob Cotsford]

servo in the bottom wing pulling on the lower wing ailerons via bottom mounted horns, top and bottom wing ailerons connected as per full size, and another cable joining the top wing ailerons via top mounted horns to complete the closed loop.  Use a spring in the top wing run to take up any slack. Depending on scale you could even run the cables through scale pullies to go from spanwise to chordwise runs.

[Richard Wicker]

Thanks to everyone for the advise on this one.

With regard to scale, it would be 1/4 but all information i have about scale pulleys report problems with slop. Has this problem now been solved with up to date materials etc, as i do admit a lot of my books, magazines etc are a bit dated.

[Bob Cotsford]

a spring in the top wing run, to eliminate slop?  A bit of trial and error would be needed to get the right strength spring and the right amount of pre-tensioning.

[Former Member]

[This posting has been removed]

[Rob Cope]

Hi All,

No experience here, but perhaps a tensioner spring pulling the line out of straight between two hard points would be good - similar to a car engine cam chain tensioner sprocket. Then you can provide various anchor points and use the appropriate one rather than having to tie off the line at exactly the right length on the spring. Maybe even tie the far end of the spring - but with far better tension control owing to the angles.  Pulleys or beeswax may be needed to provide for smooth running.  Any good?

Regards, Rob

[Yorkman]

Tony Patman wrote (see)

In David Boddington's book there is a diagram of a hidden aileron mechanism which I think is different from Eric's suggestion as I don't think it involves sliders. A hinge is fixed in the leading edge of the aileron at an angle off the plane of the aileron. A rod is attached to the other flap of the hinge, which protrudes inside the wing. As the rod is moved side-to-side, the aileron, by virtue of the angle at which the hinge is fixed, pivots up and down. The rod can therefore be actuated by a push-rod at right angles to it down the wing, either from a central servo or from a dedicated one closer to save a long rod run. I suppose you'd use a ball-link to connect them, as I think the rod attached to the hinge would need to pivot relative to the main push-rod.  Anyway, the mechanism shouldn't be any fatter than the aileron itself, and can be concealed entirely within the wing without the need for any horns or push-rods protruding outside.

It was a challenge to figure out the spacial transformations involved. After a period of waving my hands around in strange configurations, I kind-of succeeded in visualising the motion, but I have a vague intention to build a mock-up at some point just to see how it works before trying it in a model. If anyone beats me to this, or has an implementation already, I'd be interested to see some pictures.

first seen (by me) operating the ailerons of the HP Victor-which had a fairly substantial ball-with-a-hole-in sliding in a block in the t/e driving a hefty rod into the angled hinge-worked on that!

My York has a variation on the theme-pushrod parallel to the t/e bent in an open 'z' with a split pin head riding over it-as it moves from the bottom to the top of the 'z' it pivots the aileron down,and vice versa.

[Terence Lynock]

Small 4mm brass pully's are available from www.model-dockyard.com, they are usually used for rigging ships masts but could be used to rig hayleyrons etc,

regards.