ASW-15 Spoiler Adjustment

On Wednesday, May 31, 2017 at 8:46:52 PM UTC-4, Phil Chidekel wrote:
Anyone have any experience tackling asymmetric dive-brakes on an ASW-15? The left side sticks up about 30mm more than the right side, and a mechanic and I spent the day fiddling with the adjustments (to no avail). We wrote Schleicher for the drawings, but does anyone have any insight?

Thanks.

Phil Chidekel

I have used the following process with good results:
1- With wings off, check that airbrakes close and lock correctly. When they go over center you will hear and feel a bit of a snap.
2- check for any binds or signs of interference that affect smooth operation. Also look for bad bearings or bent push rods.
3- Inspect the mechanism in the fuselage to verify that the two operating bell cranks for the brakes appear to be moving the same. Also verify that the mountings for these cranks are secure.
4- Assemble the glider.
5- Connect one airbrake push rod and lock brakes. Mark the position of the handle in the cockpit when it goes over center in the wing.
6- Disconnect first wing and repeat for second wing. This should give an indication which push rod needs adjusting. Lengthening make locking sooner. Depending upon handle position, shortening the rod on the brake that closes sooner may be the right action.
7 From recollection I believe both are supposed to lock within about 5mm.
Good hunting
UH

UH and JJ,

Thank you both for your responses.

There are two adjustments we have found: one is in the baggage compartment, and one is in the wing (accessible with the bottom spoiler removed).

The adjustment in the baggage compartment seems to be a "fine-tuning" of sorts--a way to calibrate the spoiler handle's position with the position of the pushrod. The adjustment in the wing seems to adjust the breakaway tension required to make the airbrake go over center. We have adjusted the breakaway tensions to be about equal--the brakes "pop" over-center within 5 pounds of tension of each other. This was the best we could do.

We tried lengthening the in-wing adjustment on the left (hanging out) side, and it didn't seem to change the timing of when the airbrake went over center; only the tension required. Is there another adjustment that we are missing? Or are we using what we have incorrectly.

We have checked for bent pushrods and the like... Apparently, this is a known issue on the -15. I'm almost sorry we opened the can of worms to begin with.

Thanks for your insight. Old gliders are cool--when they work.

Phil

On Thursday, June 1, 2017 at 7:38:58 AM UTC-4, wrote:
On Wednesday, May 31, 2017 at 8:46:52 PM UTC-4, Phil Chidekel wrote:
Anyone have any experience tackling asymmetric dive-brakes on an ASW-15? The left side sticks up about 30mm more than the right side, and a mechanic and I spent the day fiddling with the adjustments (to no avail). We wrote Schleicher for the drawings, but does anyone have any insight?

Thanks.

Phil Chidekel

I have used the following process with good results:
1- With wings off, check that airbrakes close and lock correctly. When they go over center you will hear and feel a bit of a snap.
2- check for any binds or signs of interference that affect smooth operation. Also look for bad bearings or bent push rods.
3- Inspect the mechanism in the fuselage to verify that the two operating bell cranks for the brakes appear to be moving the same. Also verify that the mountings for these cranks are secure.
4- Assemble the glider.
5- Connect one airbrake push rod and lock brakes. Mark the position of the handle in the cockpit when it goes over center in the wing.
6- Disconnect first wing and repeat for second wing. This should give an indication which push rod needs adjusting. Lengthening make locking sooner. Depending upon handle position, shortening the rod on the brake that closes sooner may be the right action.
7 From recollection I believe both are supposed to lock within about 5mm.
Good hunting
UH

Is the offending spoiler really hanging open 30mm...........that's a bunch, close to an inch! Did you mean 3mm? With a ship that has over-center mechanisms inside each wing, I would lock the spoiler in the bad wing and then adjust the link from the over-center to the spoiler. This rod has to effect the spoiler position. Take the bolt out and move the rod by hand to see what the spoiler does. When the spoilers in both wings are in over-center (closed & locked) and the spoiler caps are flush, put the wings back on the fuselage and adjust the rods inside the fuselage to where the Hotelier fitting easily snaps on the ball.
If one spoiler really is open 30mm.............something is bent, broken, loose somewhere.........find it before you fly it!
JJ

JJ,

The discrepancy is 9mm. Just re measured--I guess I'm a stupid American who needs to learn to speak metric.

I will fiddle with it some more.

Thanks.

Phil

Even 9mm is a lot, the DG-300 had a similar problem and it was found that the root rib was deforming under closing loads. Check the mounting of all spoiler controls.........looking for a loose rib or mounting pads, etc. Check the whole spoiler by trying to move it up-dowd, for-aft, Inboard-outboard to see if the pivot points are loose. Some sing very wong here!
JJ