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#1
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Tail Wheels & Tail Booms snapp'n
I was warned about the possibility of a glassed on tail wheel possibly being the deciding factor in your tail boon snapping off in a extreme ground loop incident, whereas a skid or wheel that is intended to tear off could be the deciding factor in just the opposite happening.
I've left my steel shoe, glued on rubber skid in place, and my super faired tail wheel I made, off. Any spinout or repair people care to comment on the idea of the tail boom slamming into the turf at a high rotation speed with a hard mounted TW. |
#2
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Tail Wheels & Tail Booms snapp'n
On 11/17/2011 2:02 PM, POPS wrote:
I was warned about the possibility of a glassed on tail wheel possibly being the deciding factor in your tail boon snapping off in a extreme ground loop incident, whereas a skid or wheel that is intended to tear off could be the deciding factor in just the opposite happening. I've left my steel shoe, glued on rubber skid in place, and my super faired tail wheel I made, off. Any spinout or repair people care to comment on the idea of the tail boom slamming into the turf at a high rotation speed with a hard mounted TW. Ruh roh! This sort of question is dangerously close to FUDland. (That's FearUncertaintyDoubtland.) All fans of Absolute Certainty should read no further!!! Considered from an energy dissipation perspective, any 'tailwheel mount' that happens to break away from the fuselage dissipates a finite amount of energy from what remains in the moving glider, and in that sense reduces the possibility the next sideways load on the fuselage will have sufficient energy to break the tailboom. That said, side-load-inducing events are by nature pretty much uncontrollable (once underway, dry chuckle), dynamic, and unpredictable...meaning analytical results will always be arguably applicable. The fact is, absolute answers to the posed question won't be found in reality. That said, I know of a Zuni (solidly-mounted, fixed tailwheel, albeit by original design) that has never had a broken tailboom in 2050+ hours. Make of that what you will, but I'm of the school that believes Joe Pilot can far better control the *likelihood* of a groundloop through his actions, than he can the *nature* of any J.P.-induced groundloop. YMMV Bob W. |
#3
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Tail Wheels & Tail Booms snapp'n
On Thursday, November 17, 2011 9:31:36 PM UTC-5, BobW wrote:
... That said, side-load-inducing events are by nature pretty much uncontrollable (once underway, dry chuckle), Stick forward to lift the tail as a groundloop develops will always reduce the possibility of the tail digging in (and tailboom damage). Remember to get the stick sharply forward next time you groundloop ! Best Regards, Dave PS: I wish I had a video of an ASW-22 groundlooping for the umpteenth time (failure to dump on one side). The pilot was quite accomplished - lifted the tail just as the tip hit the ground. No damage but one humongous cloud of dust... |
#4
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Tail Wheels & Tail Booms snapp'n
This is why it's very important to apply a large quantity of butter or
margarine to the circumference of your tailwheel before each flight. The butter reduces the side loads and thus prevents the tail boom from cracking. On Nov 17, 3:02*pm, POPS wrote: I was warned about the possibility of a glassed on tail wheel possibly being *the deciding factor in your tail boon snapping off in a extreme ground loop *incident, *whereas a skid or wheel that is intended to tear off could be the deciding factor in just the opposite happening. I've left my steel shoe, glued on rubber skid in place, and my super faired tail wheel I made, off. Any spinout or repair people care to comment on the idea of the tail boom slamming into the turf at a high rotation speed with a hard mounted TW. -- POPS |
#5
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Tail Wheels & Tail Booms snapp'n
On Nov 17, 4:02*pm, POPS wrote:
I was warned about the possibility of a glassed on tail wheel possibly being *the deciding factor in your tail boon snapping off in a extreme ground loop *incident, *whereas a skid or wheel that is intended to tear off could be the deciding factor in just the opposite happening. I've left my steel shoe, glued on rubber skid in place, and my super faired tail wheel I made, off. Any spinout or repair people care to comment on the idea of the tail boom slamming into the turf at a high rotation speed with a hard mounted TW. -- POPS The currently popular large tail wheels do a good job of helping keep the glider straight which seems to help avoid the problem in the first place. Once they are seriously sideways in a true ground loop, they slide reasonably well. Once the tail digs in, the boom breaks. Does a break away skid/tailhweel avoid this? maybe -sometimes. I've put a number of modern tailwheels in older skid equipped gliders and every owner has bee happy with the improvement. FWIW UH |
#6
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Tail Wheels & Tail Booms snapp'n
Hmmm,
I have repaired maybe 15 broken booms including 3 that I have cardinal knowledge of and it is my humble opinion that the tail wheel dragging sideways has little to do with snapping the boom. In all 3 of my personal recollections, the tail was off the ground during the event (2 had wheels, 1 had a skid). I watched a Discus come as close as it could to breaking its boom when it landed beside me, only a bit deeper into the barley field at Camby, Ca The left wing tip caught a clump of barley and around it came, tail off the ground, spun 180, T-tail laid over a good 30 degrees, then the boom came down and she just sat there and shook for a moment. What determines weather you break the boom or not is speed, ground loop below 40 knots and you will probably come out unscathed, do it above 40 and she's likely to break (Libells reduce by 10 knots). What's really going on is simply this, The wing can take it quite well because it has a spar, the boom doesn't and one side goes into compression while the other is held in tension, compression looses and buckles inward, do it hard enough (speed) and she snaps off, tail wheel had very little to do with it. As always, just my humble opinion, JJ |
#7
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Tail Wheels & Tail Booms snapp'n
JJ,
If I may add.... The torsional load of the T tail, especially with lead weight installed is a big factor as well. I do not believe the style of tail wheel is a factor in tail boom fractures. The style of landing, on the other hand... Rex |
#8
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Tail Wheels & Tail Booms snapp'n
Guys - Tail up prevents catching on rough ground
and reduces side-load on tailboom if in crops. Tail up if you start to groundloop ! See ya, Dave |
#9
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Tail Wheels & Tail Booms snapp'n
On Nov 20, 5:32*pm, Dave Nadler wrote:
Guys - Tail up prevents catching on rough ground and reduces side-load on tailboom if in crops. Tail up if you start to groundloop ! See ya, Dave I have to disagree here as far as suggesting some technique thet is planned. Tail up almost ensures a ground loop. Tail down reduces the likelyhood of a groundloop substantially. Very few ground loops occur as a planned event(the "I'm running out of field" event). The strong majority are surprises caused by catch a wing. I most cases, the lower energy in the event that come from a slow held off landing significantly reduces the likelyhood of a fuselage breaking event. If you lose it, you don't have much time to try to raise the tail. Just squeeze the brake hard and hope for the best. Another opinion FWIW. UH |
#10
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Tail Wheels & Tail Booms snapp'n
Sorry if I wasn't clear:
Tail up AFTER ground-loop starts or is inevitable, not first. There's plenty of time to respond. This is *after* a fully held off tail-first landing. Seen it done multiple times ;-) Do wish I had a video of the 22 going around. PS: Most of these guys have Tost brakes so squeezing won't do anything... |
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