A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Soaring
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Wheel brake effectiveness standards



 
 
Thread Tools Display Modes
  #11  
Old October 17th 20, 08:14 PM posted to rec.aviation.soaring
Tango Eight
external usenet poster
 
Posts: 928
Default Wheel brake effectiveness standards

On Saturday, October 17, 2020 at 1:37:06 PM UTC-4, Tango Eight wrote:
Let me provide another perspective.


Should have included this (love those clouds!):

https://www.youtube.com/watch?v=oBexl9GfKK0

T8
Ads
  #12  
Old October 17th 20, 09:51 PM posted to rec.aviation.soaring
AS
external usenet poster
 
Posts: 570
Default Wheel brake effectiveness standards

On Saturday, October 17, 2020 at 12:01:39 PM UTC-4, Kenn Sebesta wrote:
On Saturday, October 17, 2020 at 10:29:03 AM UTC-4, AS wrote:
I flew my club's B4 a bit and as far as I remember, the wheel brake was actuated by a bike-brake type handle on the stick, so one didn't have to release the spoiler handle.


If you think about the ergonomics of that handle, you need to release pressure on the airbrake handle in order to open your hand and warp your fingers around the wheel brake lever. It's extremely unergonomic to actuate the two at the same time with any degree of precision, which is what leads me to believe that they didn't really design the system to have great braking performance. It strikes me more like an afterthought, something they threw in so that we could control how far we roll once we're below 10km/h.

The old Schleicher gliders Ka6, Ka8, etc. had a 'steel band over the tire' brake, which worked ok in dry conditions but were useless on wet grass, yet they were certified gliders. IIRC, the POH called it an 'emergency' brake, i.e. only use them if you are about to go through a fence.


This is a great data point!

I would call 'locking up the wheel at touchdown-speed and MTOW' the upper spec limits of any requirement.


Immediately on touchdown there's very little force on the wheel because most of the plane's weight is still carried by lift. Do you mean that you should be able to lock it up at any point during touchdown?


... you need to release pressure on the airbrake handle in order to open your hand and warp your fingers around the wheel brake lever. It's extremely unergonomic to actuate the two at the same time with any degree of precision, which is what leads me to believe that they didn't really design the system to have great braking performance.


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.

Do you mean that you should be able to lock it up at any point during touchdown?

No - only after the wheel(s) are firmly planted on terra firma can any meaningful brake action begin. That's why the big planes have 'squat switches', which look at the condition of the landing gear struts/dampers and only allow braking to start in earnest when they are activated, i.e. after the landing gear is 'loaded'.

Uli
'AS'
  #13  
Old October 17th 20, 10:51 PM posted to rec.aviation.soaring
Martin Gregorie[_6_]
external usenet poster
 
Posts: 561
Default Wheel brake effectiveness standards

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

  #14  
Old October 17th 20, 11:09 PM posted to rec.aviation.soaring
Dan Daly[_2_]
external usenet poster
 
Posts: 678
Default 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


and SZD-55 wheel brake is at the rear of spoiler handle travel as well.

  #15  
Old October 18th 20, 12:24 AM posted to rec.aviation.soaring
AS
external usenet poster
 
Posts: 570
Default 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'
  #16  
Old October 18th 20, 02:35 AM posted to rec.aviation.soaring
jmurtari
external usenet poster
 
Posts: 3
Default Wheel brake effectiveness standards

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
  #17  
Old October 18th 20, 03:04 AM posted to rec.aviation.soaring
Brian[_1_]
external usenet poster
 
Posts: 390
Default Wheel brake effectiveness standards

@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
  #18  
Old October 18th 20, 03:19 AM posted to rec.aviation.soaring
Kenn Sebesta
external usenet poster
 
Posts: 22
Default Wheel brake effectiveness standards

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.

Oh, that's interesting. I've only ever flown the one B-4, and its wheel brake is a separate lever on the airbrake handle. This means that you can't squeeze it at the same time as you're pulling back against the airbrake springs.

The B-4 in this video has the same setup: https://www.youtube.com/watch?v=Zws1Fy_yNGE.
  #19  
Old October 18th 20, 03:54 AM posted to rec.aviation.soaring
Kenn Sebesta
external usenet poster
 
Posts: 22
Default Wheel brake effectiveness standards

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.
  #20  
Old October 18th 20, 05:16 AM posted to rec.aviation.soaring
AS
external usenet poster
 
Posts: 570
Default Wheel brake effectiveness standards

On Saturday, October 17, 2020 at 10:19:53 PM UTC-4, Kenn Sebesta 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.


Oh, that's interesting. I've only ever flown the one B-4, and its wheel brake is a separate lever on the airbrake handle. This means that you can't squeeze it at the same time as you're pulling back against the airbrake springs.

The B-4 in this video has the same setup: https://www.youtube.com/watch?v=Zws1Fy_yNGE.


I see what you mean now! This is not the way I remember the set-up in our B4. Does your B4 have the fixed or retractable gear?

Uli
'AS'
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Beringer Disc Brake Kit for Schemm-Hirth gliders - experience and effectiveness? WaltWX[_2_] Soaring 35 October 20th 17 08:15 AM
SZD-55 Wheel Brake Adjustment WDM Soaring 2 January 20th 11 10:25 AM
looking for wheel/tire/brake Brad[_2_] Soaring 1 July 29th 10 02:56 AM
SZD-55 Wheel Brake David Pye[_2_] Soaring 4 September 19th 07 03:10 AM
SZD-55 Wheel Brake David Pye[_2_] Soaring 0 September 18th 07 06:01 PM


All times are GMT +1. The time now is 02:28 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright 2004-2020 AviationBanter.
The comments are property of their posters.