ASW automatic tail hookup mod?

On Monday, March 2, 2015 at 4:13:11 PM UTC+2, wrote:
On Monday, March 2, 2015 at 6:49:32 AM UTC-5, wrote:
On Sunday, March 1, 2015 at 5:36:08 PM UTC+2, wrote:
On Saturday, February 28, 2015 at 10:29:06 PM UTC-6, Stu wrote:
I owned an ASW-20A for 25 years. Now have a 27. I was very careful in checking the hookups (like JJ). You will want to add to your list to check the tail bolt - yes, I flew all afternoon in mountain turbulence with the tail bolt in my pocket!! That 3M white tape holds very well!

I also know of a modification that can be done to the top of the tail so that the elevator push rod will still push the elevator up, even if the hookup is not connected. Not sure this would help unless the CG was 60%+. I never did this mod and decided it was best to double check the hookups.

Stu. 2Z

Stu,
That story of the elevator bolt in your pocket made my skin crawl. Can't believe you got away with that. 3M wingtape is the best, though.

Remember- the bolt is "just" a safety. The forces are taken up by pins and sockets in the joint itself. And yes... the safety bolt has its own safety wire/spring :-)
Uri
4XGGG

Not correct. The bolt holds the leading edge down. I know of a couple cases where the bolt was forgotten and tape held tail on, but it is more than a bit scary. No bolt- no tape- the tail is very likely to come off, especially on a bumpy field. There is no excuse for forgotten bolt of elevator connection. That is why we push the critical assembly check so hard.
UH

UH,
I beg to differ: the bolt holds the stabilizer from moving forward. In the assembly there are a couple of (horizontal) pins which engage with the sockets in the vertical stabilizer's spar. (A drawing is on the Yahoo ASW20 group. Look for a file called "200_38-37_S1_BL1.pfd"). Those pins are the ones which take the vertical loads.
Tape can eaily keep the horizontal stabilizer from moving forward under all flying conditions I can think of.
Not that I would want to fly without that bolt, of course. And if I did, I am not sure what shade my face would become 8-).
Safe landings,
Uri
4X-GGG

Remember the Ventus driver who slid the elevator in place and was just about to secure it with the little red knob, when he got a phone call (before cell phones), went to the office and answered the phone. Came back, jumped in and towed off! Elevator flipped up at something like 500 feet....................He is no longer with us!

Then there was the Genesis driver who slid the elevator on and couldn't secure it because he had given the little red knob to his wife so she could start putting water in the wings. Figured he would get it later...................He got it about 30 minutes later when the elevator fell off on the runway! Could have survived that, but he never heard the line boy calling RELEASE RELEASE RELEASE, because he was on the wrong frequency!

Rush.....Rush......Rush = Dead.....Dead.....Dead

JJ

On Sunday, March 8, 2015 at 4:55:22 PM UTC+2, JJ Sinclair wrote:
Remember the Ventus driver who slid the elevator in place and was just about to secure it with the little red knob, when he got a phone call (before cell phones), went to the office and answered the phone. Came back, jumped in and towed off! Elevator flipped up at something like 500 feet....................He is no longer with us!

Then there was the Genesis driver who slid the elevator on and couldn't secure it because he had given the little red knob to his wife so she could start putting water in the wings. Figured he would get it later...................He got it about 30 minutes later when the elevator fell off on the runway! Could have survived that, but he never heard the line boy calling RELEASE RELEASE RELEASE, because he was on the wrong frequency!

Rush.....Rush......Rush = Dead.....Dead.....Dead

JJ

JJ,
These cautionary tales are all good and true, but if you are answering my post, I am only arguing the technical side of why *on an ASW-20* the tail would stay on if the bolt is forgotten.
FWIW, there is an optional TN to add a little O-ring to the bolt so that it stays on the elevator when di-rigged, and sticks out visibly if, when rigged, it is not screwed in. This calls for machining the bolt, arguably weakening it...probably not a good idea were it not that it is not meant to take any vertical forces. (here is a link to it: http://www.alexander-schleicher.de/t...enbolzen_E.pdf ).

Uri

On Sunday, March 8, 2015 at 4:07:53 AM UTC-7, wrote:

UH,
I beg to differ: the bolt holds the stabilizer from moving forward. In the assembly there are a couple of (horizontal) pins which engage with the sockets in the vertical stabilizer's spar. (A drawing is on the Yahoo ASW20 group. Look for a file called "200_38-37_S1_BL1.pfd"). Those pins are the ones which take the vertical loads....

Well, sort of. Those pins do react the a lot of the lift loads, but don't help much with loads that try to lift the stabilizer's leading edge. In the absence of the tape, a lifting force that raises the leading edge could easily have bent the plate that anchors the spar pins and allowed the stabilizer to fly free. In most high-performance sailplanes, the tailplane does indeed lift upward when flying at low speed at anywhere but the most forward part of the CG envelope.

For the HP-24 sailplane, I chose to adopt (or "leverage," in Silicon Valley speak) the thumbwheel system used for attaching the stabilizer in Wolf Lemke's LS-series sailplanes. In that system, if the stabilizer is not secured enough to go flying, it will be so loose on the fin top that it will be clearly insecure and unsafe.

Thanks, Bob K.

On Sunday, March 8, 2015 at 6:23:37 PM UTC+2, Bob Kuykendall wrote:
On Sunday, March 8, 2015 at 4:07:53 AM UTC-7, wrote:

UH,
I beg to differ: the bolt holds the stabilizer from moving forward. In the assembly there are a couple of (horizontal) pins which engage with the sockets in the vertical stabilizer's spar. (A drawing is on the Yahoo ASW20 group. Look for a file called "200_38-37_S1_BL1.pfd"). Those pins are the ones which take the vertical loads....

Well, sort of. Those pins do react the a lot of the lift loads, but don't help much with loads that try to lift the stabilizer's leading edge. In the absence of the tape, a lifting force that raises the leading edge could easily have bent the plate that anchors the spar pins and allowed the stabilizer to fly free. In most high-performance sailplanes, the tailplane does indeed lift upward when flying at low speed at anywhere but the most forward part of the CG envelope.

For the HP-24 sailplane, I chose to adopt (or "leverage," in Silicon Valley speak) the thumbwheel system used for attaching the stabilizer in Wolf Lemke's LS-series sailplanes. In that system, if the stabilizer is not secured enough to go flying, it will be so loose on the fin top that it will be clearly insecure and unsafe.

Thanks, Bob K.

Thanks Bob, Got it.
Uri