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. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Pawnee Tow Hook STC
Greetings,
Does anybody have any information about Tost or Schweizer tow hook STCs for a Pawnee? Our A&P hasn't found any info. Does it require a field approval or is their an STC out there? Thanks, Shawn |
#2
|
|||
|
|||
I know nothing at all about the regulations, paperwork etc. required for
fitting tow hooks in the USA. However, if you fit a Schweizer hook PLEASE make sure that it is modified to make it easier to release under load. Remember that it is a banner towing hook, and no-one gets killed if you can't release the banner! There is a modification to the Schweizer hook in the U.K., this was done after we killed a few tug pilots. The modification to Schweizer type banner towing hooks is approved and highly recommended by the BGA. It may be found at: British Gliding Association. http://www.gliding.co.uk/ Go to: Info for Clubs & Members. http://www.gliding.co.uk/bgainfo/news.htm Go to: Technical. http://www.gliding.co.uk/bgainfo/technical/news.htm Go to: Airworthiness Directives. http://www.gliding.co.uk/bgainfo/technical/ads.htm Go to: Motor Glider and Tug issues. http://www.gliding.co.uk/bgainfo/tec...iderandtug.pdf See: Page 2 - item 14. Schweitzer type banner towing hooks. You will not be able to view the mod. on-line, or download it; but I am sure they will mail it to you (let me know if you have problems). The release wire is attached to a double flat bar which pivots on a bolt at the bottom through the fixed part of the hook. Half way along the bar is a round stud which has to slide forward on the upward releasing fitting in order to release. It is high friction between this stud and the releasing fitting which causes the problem (high release loads when the towrope is under high tension). The fix is to put in a roller bearing instead of the round stud, so that it rolls off the releasing fitting instead of sliding. W.J. (Bill) Dean (U.K.). Remove "ic" to reply. "Shawn Curry" wrote in message link.net... Greetings, Does anybody have any information about Tost or Schweizer tow hook STCs for a Pawnee? Our A&P hasn't found any info. Does it require a field approval or is their an STC out there? Thanks, Shawn |
#3
|
|||
|
|||
Shawn,
The only STC I have found is one Schweizer owns for the Piper PA-18. It appears the FAA is going to stop field approvals for tow hooks. Their latest statement," there must be an STC or be listed in the Type Certification Data Sheet for the aircraft". This could be costly. Sam Fly Texas Soaring Association Shawn Curry wrote: Greetings, Does anybody have any information about Tost or Schweizer tow hook STCs for a Pawnee? Our A&P hasn't found any info. Does it require a field approval or is their an STC out there? Thanks, Shawn |
#4
|
|||
|
|||
I can remember the people at Turf talking about getting
FAA approval for modifing the Schweizer tow hook by inverting it and other improvements. I suggest you contact Turf directly for this info. Roy would surely be able to steer you in the right direction. Turf Soaring School 602-439-3621. At 13:30 21 January 2004, Sam Fly wrote: Shawn, The only STC I have found is one Schweizer owns for the Piper PA-18. It appears the FAA is going to stop field approvals for tow hooks. Their latest statement,' there must be an STC or be listed in the Type Certification Data Sheet for the aircraft'. This could be costly. Sam Fly Texas Soaring Association Shawn Curry wrote: Greetings, Does anybody have any information about Tost or Schweizer tow hook STCs for a Pawnee? Our A&P hasn't found any info. Does it require a field approval or is their an STC out there? Thanks, Shawn |
#5
|
|||
|
|||
Thanks for the posts,
If anyone has some digital images of Schweitzer or Tost hook installations on a Pawnee, they would be greatly appreciated. Also any comments on how the paperwork was processed. It appears no STC exists. This is for a US aircraft. At 16:00 21 January 2004, Cliff Hilty wrote: I can remember the people at Turf talking about getting FAA approval for modifing the Schweizer tow hook by inverting it and other improvements. I suggest you contact Turf directly for this info. Roy would surely be able to steer you in the right direction. Turf Soaring School 602-439-3621. At 13:30 21 January 2004, Sam Fly wrote: Shawn, The only STC I have found is one Schweizer owns for the Piper PA-18. It appears the FAA is going to stop field approvals for tow hooks. Their latest statement,' there must be an STC or be listed in the Type Certification Data Sheet for the aircraft'. This could be costly. Sam Fly Texas Soaring Association Shawn Curry wrote: Greetings, Does anybody have any information about Tost or Schweizer tow hook STCs for a Pawnee? Our A&P hasn't found any info. Does it require a field approval or is their an STC out there? Thanks, Shawn |
#6
|
|||
|
|||
Shawn
These links address the problem- Much thanks to Jim Burch and his contributuon to soaring. http://home.att.net/~jdburch/index.htm http://home.att.net/~jdburch/towhook.htm http://home.att.net/~jdburch/Form337.htm http://home.att.net/~jdburch/Towstudy.htm This applys to the Schweizer hooks: "On rare occasions it is possible for a glider on aerotow takeoff to get so high that the tow plane tail is lifted even with full up elevator by the tow pilot. It is also possible in this situation for the tow plane release to jam and prevent release by the tow pilot. One solution to ensure that the tow pilot can release when this happens is to invert the release hook. To review an article on this subject from the May 1996 issue of Soaring, select Towhook Article. Select FAA Form 337 for documentation of such a modification to a Pawnee tow plane, and Towing Analysis for the study upon which the article is based." In my opinion the TOST hooks by far are the better answer although initial cost and maintainence costs are a factor. Good Luck. Rod |
#7
|
|||
|
|||
"W.J. \(Bill\) Dean \(U.K.\)." wrote in message ...
There is a modification to the Schweizer hook in the U.K., this was done after we killed a few tug pilots. There is also a modification to the Schweizer hook (actually, a mod to the mount) that is approved in the US, it consists of turning the release assembly upside down, so that any upward load is taken against the fixed part of the release and not the hinged arm. This prevents an excessive upward load from jamming the release. Contact Turf Soaring at http://www.turfsoaring.com/ for more info on this mod (it was apparently invented by one of Turf's tow pilots). All of Turf's Pawnees have this mod installed. Kirk |
#8
|
|||
|
|||
Shawn Curry wrote in message hlink.net...
Greetings, Does anybody have any information about Tost or Schweizer tow hook STCs for a Pawnee? Our A&P hasn't found any info. Does it require a field approval or is their an STC out there? Thanks, Shawn FAA form 337 for installing an inverted Schweizer hook can be found at http://home.att.net/~jdburch/Form337.htm The site also contains related links. Andy |
#9
|
|||
|
|||
"W.J. \(Bill\) Dean \(U.K.\)." wrote in message ...
I know nothing at all about the regulations, paperwork etc. required for fitting tow hooks in the USA. However, if you fit a Schweizer hook PLEASE make sure that it is modified to make it easier to release under load. Remember that it is a banner towing hook, and no-one gets killed if you can't release the banner! There is a modification to the Schweizer hook in the U.K., this was done after we killed a few tug pilots. The modification to Schweizer type banner towing hooks is approved and highly recommended by the BGA. It may be found at: British Gliding Association. http://www.gliding.co.uk/ Go to: Info for Clubs & Members. http://www.gliding.co.uk/bgainfo/news.htm Go to: Technical. http://www.gliding.co.uk/bgainfo/technical/news.htm Go to: Airworthiness Directives. http://www.gliding.co.uk/bgainfo/technical/ads.htm Go to: Motor Glider and Tug issues. http://www.gliding.co.uk/bgainfo/tec...iderandtug.pdf See: Page 2 - item 14. Schweitzer type banner towing hooks. You will not be able to view the mod. on-line, or download it; but I am sure they will mail it to you (let me know if you have problems). The release wire is attached to a double flat bar which pivots on a bolt at the bottom through the fixed part of the hook. Half way along the bar is a round stud which has to slide forward on the upward releasing fitting in order to release. It is high friction between this stud and the releasing fitting which causes the problem (high release loads when the towrope is under high tension). The fix is to put in a roller bearing instead of the round stud, so that it rolls off the releasing fitting instead of sliding. W.J. (Bill) Dean (U.K.). Remove "ic" to reply. "Shawn Curry" wrote in message link.net... Greetings, Does anybody have any information about Tost or Schweizer tow hook STCs for a Pawnee? Our A&P hasn't found any info. Does it require a field approval or is their an STC out there? Thanks, Shawn Phila. Glider has installed Tost on Pawnee, contact me for details |
#10
|
|||
|
|||
PGC got field approvals in 2003 for the installation of Tost hooks on both a
Pawnee and a Cessna L-19. From a safety standpoint the Tost installation is the way to go. Bob |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Tow Hook on Cessna 180 - Update | Stuart Grant | Soaring | 13 | April 10th 20 10:48 AM |
CG hook on aero tows?? | Ted Wagner | Soaring | 130 | January 12th 04 11:04 PM |
Tow Hook on Cessna 180? | Stuart Grant | Soaring | 3 | October 2nd 03 12:50 AM |
FS Pawnee tugs | Robert Danewid | Soaring | 0 | August 9th 03 09:51 AM |
CG hook & Low Tow | Ray Lovinggood | Soaring | 2 | July 25th 03 06:20 AM |