Original Posted By: Alan Swanson
Subject: Split landing gear/shock cord question....Hello Group,I used the same shock strut design the Piper J-3 uses. The dimensionbetween the spools is the same and the spools are 90 degrees to eachother when looking along the strut. The only departure from the Piper de-sign is that the lower (outboard) part is a bit shorter than the J-3 partanda universal link (as found on a Piper PA-17 Vagabond shock strut) is usedat the attachment point to the axle.If you use one 1280HD shock ring (for J-3) and one 9010HD ring ( Taylor-craft BC12D) on each side with the above setup, you will be happy with theresults. I have used this arrangement with great success for nearly thirtyyears and wouldn't change it in any way. Initially, I tried using two 9010T'Craft rings per side (far too soft). Two 1280 rings per side (as used on aJ-3 or Vagabond) is too firm for my Pietenpol (1150 lbs. max. weight).If you use the setup in the Pietenpol plans, you cannot use shock ringsbecause the spools lie in the same plane when looking down the lengthof the strut. My son once owned a Pietenpol with this shock strut styleand we used about 10 feet of 1/2 inch shock cord per side, having loopson each end. These loops are formed by "serving" the overlapping portionwith rib lacing (stitching) cord. See old aircraft mechanic books (or oldaircraft mechanics) for details. The number of wraps of shock cord aroundthe spools will give you the "ride" you desire, but it is better to haveshockcord on the tight side rather than loose and soft; shock cord cannot absorbenergy effectively if it isn't sufficiently pre-stretched. Of couse, it willbe use-less if stretched to, or nearly to, its limit. Experimentation to obtain thede-sired "give" is necessary.It is always a good plan to protect shock cord or rings from oil, grease andsunlight by using covers.I am not submitting this information with the idea that this is the only waytoset up your shock struts. Rather, it is intended to be for information only.Itmay be helpful in making your own shock absorbing system.Cheers,Graham Hansen (CF-AUN)________________________________________________________________________________Date: Sun, 13 Feb 2000 22:35:01 -0600
Pietenpol-List: Fw: Split landing gear/shock cord question....
Pietenpol-List: Fw: Split landing gear/shock cord question....
Original Posted By: Graham Hansen
-----Original Message-----
-----Original Message-----
Re: Pietenpol-List: Fw: Split landing gear/shock cord question....
Original Posted By: "Graham Hansen"
Thanks Graham! I started the original thread and this is helpful..Bert----- Original Message -----
Thanks Graham! I started the original thread and this is helpful..Bert----- Original Message -----
> Split landing gear/shock cord question....
Original Posted By: "Gary Meadows"
> Subject: Split landing gear/shock cord question....>>> Hello Group,>> I used the same shock strut design the Piper J-3 uses. The dimension> between the spools is the same and the spools are 90 degrees to each> other when looking along the strut. The only departure from the Piper de-> sign is that the lower (outboard) part is a bit shorter than the J-3 part> and> a universal link (as found on a Piper PA-17 Vagabond shock strut) is used> at the attachment point to the axle.>> If you use one 1280HD shock ring (for J-3) and one 9010HD ring ( Taylor-> craft BC12D) on each side with the above setup, you will be happy with the> results. I have used this arrangement with great success for nearly thirty> years and wouldn't change it in any way. Initially, I tried using two 9010> T'Craft rings per side (far too soft). Two 1280 rings per side (as used ona> J-3 or Vagabond) is too firm for my Pietenpol (1150 lbs. max. weight).>> If you use the setup in the Pietenpol plans, you cannot use shock rings> because the spools lie in the same plane when looking down the length> of the strut. My son once owned a Pietenpol with this shock strut style> and we used about 10 feet of 1/2 inch shock cord per side, having loops> on each end. These loops are formed by "serving" the overlapping portion> with rib lacing (stitching) cord. See old aircraft mechanic books (or old> aircraft mechanics) for details. The number of wraps of shock cord around> the spools will give you the "ride" you desire, but it is better to have> shock> cord on the tight side rather than loose and soft; shock cord cannotabsorb> energy effectively if it isn't sufficiently pre-stretched. Of couse, itwill> be use-> less if stretched to, or nearly to, its limit. Experimentation to obtainthe> de-> sired "give" is necessary.>> It is always a good plan to protect shock cord or rings from oil, greaseand> sunlight by using covers.>> I am not submitting this information with the idea that this is the onlyway> to> set up your shock struts. Rather, it is intended to be for informationonly.> It> may be helpful in making your own shock absorbing system.>> Cheers,>> Graham Hansen (CF-AUN)>>________________________________________________________________________________
> Subject: Split landing gear/shock cord question....>>> Hello Group,>> I used the same shock strut design the Piper J-3 uses. The dimension> between the spools is the same and the spools are 90 degrees to each> other when looking along the strut. The only departure from the Piper de-> sign is that the lower (outboard) part is a bit shorter than the J-3 part> and> a universal link (as found on a Piper PA-17 Vagabond shock strut) is used> at the attachment point to the axle.>> If you use one 1280HD shock ring (for J-3) and one 9010HD ring ( Taylor-> craft BC12D) on each side with the above setup, you will be happy with the> results. I have used this arrangement with great success for nearly thirty> years and wouldn't change it in any way. Initially, I tried using two 9010> T'Craft rings per side (far too soft). Two 1280 rings per side (as used ona> J-3 or Vagabond) is too firm for my Pietenpol (1150 lbs. max. weight).>> If you use the setup in the Pietenpol plans, you cannot use shock rings> because the spools lie in the same plane when looking down the length> of the strut. My son once owned a Pietenpol with this shock strut style> and we used about 10 feet of 1/2 inch shock cord per side, having loops> on each end. These loops are formed by "serving" the overlapping portion> with rib lacing (stitching) cord. See old aircraft mechanic books (or old> aircraft mechanics) for details. The number of wraps of shock cord around> the spools will give you the "ride" you desire, but it is better to have> shock> cord on the tight side rather than loose and soft; shock cord cannotabsorb> energy effectively if it isn't sufficiently pre-stretched. Of couse, itwill> be use-> less if stretched to, or nearly to, its limit. Experimentation to obtainthe> de-> sired "give" is necessary.>> It is always a good plan to protect shock cord or rings from oil, greaseand> sunlight by using covers.>> I am not submitting this information with the idea that this is the onlyway> to> set up your shock struts. Rather, it is intended to be for informationonly.> It> may be helpful in making your own shock absorbing system.>> Cheers,>> Graham Hansen (CF-AUN)>>________________________________________________________________________________