Tie Down – How tight?
Question:
I don’t so much "haunt" as I do scan. (Don’t have time for both the newsgroups and AvSig in depth.) As for what’s next, there an accident review looking at time in type and Stupid Pilot Tricks II, The Movie for *IFR* sometime in the next couple of months, I think. – Hide quoted text — Show quoted text – David, .stuff snipped Jane Garvey, NOT the FAA Administrator. Jane, Glad to see you haunting the newsgroups. Look forward to your next contribution to IFR (or was that Aviation Consumer?). Cheers, Mike
NOT the FAA Administrator.
Response:
Makes sense to me. On the other hand, I’ve seen photos of I think it was 59 adults standing on the underside of an inverted 172 (demo by Cessa) to depict visually what the normal category safe load factor is. I’m not an expert either way, but decided a long time ago for my own purposes that I prefer good, stout, natural fiber ropes. – Hide quoted text — Show quoted text – The use of chains for tie-downs is very strongly discouraged here in Anchorage. Most light aircraft are tied down outside and subject to strong winds at certain times of the year. A few years ago, a prominent local judge was killed when his SuperCub wing came off in flight. I understand the accident investigation concluded that his use of chains contributed to the failure of the strut to wing spar fitting resulting from the non-elastic transmission of severe wind wing rocking shock to the fitting. Chains simply do not absorb much shock. Many locals do use a variety of methods to create spoilers. Some wing covers have a roll of fabric running spanwise. These help in winter storms. Others actually place boards on the top of the wing, much like a sailplane spoiler. Raising the tail to reduce the angle of attack seems to work as well for conventional geared planes to reduce the lifting force. Pete to reply delete "IHATESPAM"
NOT the FAA Administrator.
Response:
says… I have *heard*, but cannot verify, that natural fiber ropes are better in general, having more give and are therefore less likely to snap than synthetic. Obviously, if the hemp rope is thin, rotten or frayed, all bets are off.
As far as I know synthetic fibre is *much* more stretchable than hemp (and probalby most other natural fibres). qv: climbing ropes. I think you can prove this very easily too – just try it out! – stretch it by hand. So other than that we point – note also that: Most natural fibre ropes will *shrink* when wet. Synthetic will do the very opposite! So when tying down (and it’s wet) you can tie down a *wee* bit tighter with hemp type ropes, knowing that they’ll slacken as the dry. But beware the opposite for syntethic ropes, they’ll shrink upon drying. — Regards Duncan McC http://www.adrock.com http://www.imagineradio.com/mymusiclisten.asp?name=DuncanMcC
Response:
David, We had a Category 5 hurricane come inland about 150 miles a couple of years ago over my home field. The aircraft that were tied down with ropes were slewed to one side, all at the same angle (peculiar sight) and the ropes were very taut, but they held. The one plane on the entire field that broke loose was a low wing that had been secured by light weight chains. The tail chain broke, one chain pulled the ring out of one wing and it flipped over via the remaining attachment onto another aircraft. Down at our coast, when the gales are regular and strong, the "tie downs" provided are logging chains and humongous S-hooks. I have *heard*, but cannot verify, that natural fiber ropes are better in general, having more give and are therefore less likely to snap than synthetic. Obviously, if the hemp rope is thin, rotten or frayed, all bets are off. I have also heard that for extraordinary anticipated winds, some pilots will duct tape a 2×4 to the upper forward portion of the wing to "spoil" the lift. Jane Garvey, NOT the FAA Administrator.
Response:
The use of chains for tie-downs is very strongly discouraged here in Anchorage. Most light aircraft are tied down outside and subject to strong winds at certain times of the year. A few years ago, a prominent local judge was killed when his SuperCub wing came off in flight. I understand the accident investigation concluded that his use of chains contributed to the failure of the strut to wing spar fitting resulting from the non-elastic transmission of severe wind wing rocking shock to the fitting. Chains simply do not absorb much shock. Many locals do use a variety of methods to create spoilers. Some wing covers have a roll of fabric running spanwise. These help in winter storms. Others actually place boards on the top of the wing, much like a sailplane spoiler. Raising the tail to reduce the angle of attack seems to work as well for conventional geared planes to reduce the lifting force. Pete – Hide quoted text — Show quoted text – The one plane on the entire field that broke loose was a low wing that had been secured by light weight chains. The tail chain broke, one chain pulled the ring out of one wing and it flipped over via the remaining attachment onto another aircraft. Down at our coast, when the gales are regular and strong, the "tie downs" provided are logging chains and humongous S-hooks. I have *heard*, but cannot verify, that natural fiber ropes are better in general, having more give and are therefore less likely to snap than synthetic. Obviously, if the hemp rope is thin, rotten or frayed, all bets are off. I have also heard that for extraordinary anticipated winds, some pilots will duct tape a 2×4 to the upper forward portion of the wing to "spoil" the lift. Jane Garvey,
Own — Peter D. Brown 8731 Sultana Dr. Anchorage, Ak 99516 907-345-7529 (home) 907-564-0223 (fax) F to reply delete "IHATESPAM"
Response:
Unfortunately some UK airfields seem to use concrete in cans and place them
below the wings! I have often wondered if this is sufficient weight to be much use.
I do not believe using weights for tie downs does you much good. After all, the wing generates enough lift to carry the plane so surely it would drag off any deadfalls in a stiff wind? Regards, Todd
Response:
Only leave as much slack equal to the distance you are willing to walk to pick up all the pieces of what’s left of your plane. Keep them tight and don’t tie slip knots.
Response:
David, .stuff snipped Jane Garvey, NOT the FAA Administrator.
Jane, Glad to see you haunting the newsgroups. Look forward to your next contribution to IFR (or was that Aviation Consumer?). Cheers, Mike
Response:
I would be interested in any comments about how tight to make the tie down ropes when securing an aircraft. In particular I fly a PA28 and when staying overnight I always tie the aircraft down. It is not only possible but probable the winds will change direction and strength. I live on the West Coast of Scotland. Mostly the anchor points are of the corkscrew type into the ground. Unfortunately some UK airfields seem to use concrete in cans and place them below the wings! I have often wondered if this is sufficient weight to be much use. Comments appreciated on just how tight the ropes should be? Is it sufficient to simply take up the slack and accept some movement due to rope stretching and movement in the knot? Should the rope be very tight to prevent any movement or is this likely to cause distortion/damage to the wings? Whilst on the subject of ropes what type of knots do you use? Thanks, Regards, David G-BHJO Scotland, UK
