by BarryL » Tue Sep 20, 2022 8:20 am
Last Sunday I noticed that the wheelbrake was coming on too early in the travel of the airbrake control.
This has the effects of restricting the amount of available airbrake and making it more likely that the wheelbrake will be on at touchdown.
This requires a minor adjustment to the wheelbrake linkage which I intend to do on Friday. However, I can't be there until the afternoon. JAD may be flown in the morning provided the pilots are aware of the issue. It was flown on Sunday with no difficulties.
Barry L
TLDR bit: Near the end of its travel, the airbrake control engages a pushrod to the wheel brake master cylinder. The point at which the wheelbrake comes on is adjusted by a screw arrangement beneath the rear seat pan.
When the brake fluid is replaced there usually seems to be some residual air left in the mechanism that works its way out over time, so there is less slack in the travel before the brake starts to engage and consequently the brake comes on earlier in the travel.
While JAD was in Poland, we asked for a better brake reservoir to be fitted, an optional modification to improve the brake system. When we got the glider back, the wheelbrake was not working properly and seemed to have air in the system, so we backflushed with fresh fluid and readjusted it. The brake has worked properly since, but now the residual air has worked itself out again and so a further adjustment is needed.
There should be 25 to 35 mm of gap between the bottom of the airbrake blades and the wing surface at full airbrake.
Last Sunday I noticed that the wheelbrake was coming on too early in the travel of the airbrake control.
This has the effects of restricting the amount of available airbrake and making it more likely that the wheelbrake will be on at touchdown.
This requires a minor adjustment to the wheelbrake linkage which I intend to do on Friday. However, I can't be there until the afternoon. JAD may be flown in the morning provided the pilots are aware of the issue. It was flown on Sunday with no difficulties.
Barry L
TLDR bit: Near the end of its travel, the airbrake control engages a pushrod to the wheel brake master cylinder. The point at which the wheelbrake comes on is adjusted by a screw arrangement beneath the rear seat pan.
When the brake fluid is replaced there usually seems to be some residual air left in the mechanism that works its way out over time, so there is less slack in the travel before the brake starts to engage and consequently the brake comes on earlier in the travel.
While JAD was in Poland, we asked for a better brake reservoir to be fitted, an optional modification to improve the brake system. When we got the glider back, the wheelbrake was not working properly and seemed to have air in the system, so we backflushed with fresh fluid and readjusted it. The brake has worked properly since, but now the residual air has worked itself out again and so a further adjustment is needed.
There should be 25 to 35 mm of gap between the bottom of the airbrake blades and the wing surface at full airbrake.