Wheel brake effectiveness standards

On Saturday, October 17, 2020 at 5:51:58 PM UTC-4, Martin Gregorie wrote:
On Sat, 17 Oct 2020 13:51:16 -0700, AS wrote:

Hi Kenn - not sure I understand! In the B4 and any other glider I am
familiar with, the spoiler handle is on the left side and there is no
brake actuation via the spoiler handle - not by pulling it back fully or
by a brake lever on that handle. The right hand is on the stick and the
brake handle is mounted on it to the front of it. It does not take a lot
of dexterity of the hand to wrap two or three fingers around the brake
handle and squeeze it while continuing to hold the stick back.

Most of the single seaters I've flown (Libelle, Discus 1, Pegase 90 use
that arrangement, but I flown a few fairly common types that don't:

- ASK-21: the wheel-brake is applied by pulling the air-brake handle back
past the (spring-loaded) fully air-brake stop. Both brakes work well.

- SZD Puchacz: the air-brake handle is too far back which makes it
awkward enough that some people can't get full air-brake, not that this
is a problem because the air-brakes and HUGE, fully speed-limiting and
tend to stay where you leave them. Just as well because the wheel brake
is a black knob on the left just in front of the air-brake handle's
forward position. Both brakes work well.

- the SZD Junior originally has a bicycle handbrake type wheel-brake but
it was on the air-brake handle rather than the stick, where its pivot
severely weakened the air-brake control assembly. There was an AD to fix
this by deleting the bicycle handbrake control and connecting the wheel
brake to the air-brake handle so that pulling against the stop with the
brakes fully out applies the wheel-brake.

- IIRC the Grop G.103 Acro also has the wheel-brake connected to the
air-brake lever but its been a long time since I flew a G.103 and our
club no longer has one so I can't check.

And lets not forget the much older gliders with nose skids (Slingsby
T.21, Schweitzer 2-33, unmodified ASK-13s*) which don't have a wheel-
brake: you just put the nose skid on the ground and maybe push on the
stick a bit to make them stop quicker.

* most of the K-13s I've flown were retro-fitted with a nose-wheel and
wheel-brake.


--
Martin | martin at
Gregorie | gregorie dot org

IIRC the Grop G.103 Acro also has the wheel-brake connected to the
air-brake lever but its been a long time since I flew a G.103 and our
club no longer has one so I can't check.
You are correct, Martin! That's how our G103 - III-Acro os set up.
To add to the list of strange brake systems: the Blechnik L13 has a lever on the floor-board next to the seat. The brake itself worked well; probably due to the great leverage one has by pulling up on a handle.

Uli
'AS'

Folks,
I'm former USAF and have really enjoyed flying gliders. I love this topic as it has mystified me and I've heard some amazing things..."if you fly a glider properly you don't need brakes." I also saw a 1-26 brake that was a flexible piece of metal that rubbed against the tread. Personally, I expect a fully applied brake to stop wheel rotation and cause a skid. Clearly the FAA does not feel that is essential in a glider....

Best regards!
John Murtari

@On Saturday, October 17, 2020 at 7:35:10 PM UTC-6, wrote:
Folks,
I'm former USAF and have really enjoyed flying gliders. I love this topic as it has mystified me and I've heard some amazing things..."if you fly a glider properly you don't need brakes." I also saw a 1-26 brake that was a flexible piece of metal that rubbed against the tread. Personally, I expect a fully applied brake to stop wheel rotation and cause a skid. Clearly the FAA does not feel that is essential in a glider....

Best regards!
John Murtari

When I did my glider transition training the Blanik L-13 i was using was waiting for brake parts from the factory and as a result did not have a working wheel brake. I did all my dual flights, most of my solo flights and my check ride in this glider with no working wheel brake.
Definitely possible to fly without a wheel brake in many, maybe even most situations, but a good wheel brake is a great safety device.

Brian

I think the summary so far is that there's an amazing range of brake effectiveness. One takeaway is that we like having brakes, but so far there are no stories about why having highly effective brakes saved the day, or alternatively why having no brakes led to an unpleasant outcome. This is a not altogether surprising result, considering that my experience mirrors the accounts here.

I'm unsure what conclusion to draw here. It certainly seems that, arguably, effective wheel brakes are seen as a nice-to-have and great wheel brakes are an unneeded luxury. As unsettling as that is to me, if after all these years there's no data to support their need, and even CS-22 barely pays them lip service, then it doesn't seem wholly unjustifiable.

I'd love some hard numbers, if they're out there.

I consider that a very peculiar conclusion. No you don't "need" a brake. You don't "need" 50:1 glide either, though it's nice to have. You don't need a parachute, except every once in a great while. You really don't "need" a glider at all.

There are plenty fo gliderports where it is expected that you will roll clear of the active runway, without hitting parked gliders, cars, spectators - for that you need a brake. If a motorglider that does any taxiing, you need a brake. If there is ever a chance of landing off field, you need a brake..

I would not own a glider without a brake. And I am quite happy to own one with a very effective brake. And most especially if designing a glider or a brake system for one, I would consider it abject incompetence in this day and age to design an ineffective one. Would you skimp on the brake to save a pound, so you can add a pound of water ballast? What exactly is the point?

On Saturday, October 17, 2020 at 7:54:28 PM UTC-7, Kenn Sebesta wrote:
I think the summary so far is that there's an amazing range of brake effectiveness. One takeaway is that we like having brakes, but so far there are no stories about why having highly effective brakes saved the day, or alternatively why having no brakes led to an unpleasant outcome. This is a not altogether surprising result, considering that my experience mirrors the accounts here.

I'm unsure what conclusion to draw here. It certainly seems that, arguably, effective wheel brakes are seen as a nice-to-have and great wheel brakes are an unneeded luxury. As unsettling as that is to me, if after all these years there's no data to support their need, and even CS-22 barely pays them lip service, then it doesn't seem wholly unjustifiable.

I'd love some hard numbers, if they're out there.

Originally Posted by jmurtari

Folks,
I'm former USAF and have really enjoyed flying gliders. I love this topic as it has mystified me and I've heard some amazing things..."if you fly a glider properly you don't need brakes." I also saw a 1-26 brake that was a flexible piece of metal that rubbed against the tread. Personally, I expect a fully applied brake to stop wheel rotation and cause a skid. Clearly the FAA does not feel that is essential in a glider....

Best regards!
John Murtari

I have a lot of time in 1-26's , they have the effective brake system you mentioned .
But I had the most longest and terrifying off field landing roll in a 1-26.
I had a failed ridge transition and picked a very long field ,it had some rolls but pretty much level. After touchdown I kept going ,and going ,and going.
I pulled and puled on the brake but Nothing! Coming to a stop 50' from the trees after what seemed like a quarter mile I exited the canopy and got down on my knees to check the brake and found the main wheel off the ground by 4"!!
Apparently the crop was not soy beans like I thought it was Alfalfa . Very dense and when crushed produces water and a slimy substance .
I guess 1-26s are not very ground loop prone in high crops LOL .