The other day I landed at my strip and when I set the tail down ( gently ) the Scott tail wheel came off. No bolt to be found, I put any bolt I could find to get it in the hangar. After about 2 hours of looking I found the spacer, the bolt and the eye. I put an AN 7-23 back in there for now and fixed the rudder that was all bent up. So did I have the eye bolt to tight, to loose, or was the bolt defective? I'v had that eye bolt on there, I think about 3 years.
I would suggest discussing this with the manufacturer and getting it into a metallurgy lab ASAP. The manufacturer should be anxous to get all the facts urgently. Please keep all up to date. Regardless of the cause, you may be able to save many others some unnecessary hazzard or at minimum some expensive grief.
Last edited by highroads; 07-12-2012 at 12:09 PM.
Don
looks like it came from a garden supply store. I never had an eye bolt in my cub tail wheel. The one in my 185 is a very spendy bolt and does not look cast like yours.
Get a replacement from ABW or go to a rigging store and get a rated lifting eye. I have an eye bolt from XP Mods on the Cessna. Wrapping a rope around the tailwheel makes for a greasy mess on that plane. Never bothered on the -12. No problems tying around the leaf spring.
It appears to have been cracked about half way through for some time because of the dirty surface on the bottom of the "eye" end where about half of the surface looks clean from the fresh break and the other half is dirty/corroded.
Jason
Tim, yours is not the first eye bolt to break. Might be a good idea to keep a spare and related pieces in the plane.
Rene
-Rene
One broken is an "isolated occurance" , two broken is a trend
Don
I know of two more.......... Because of them, I took mine out of the Scout (real heavy tail) this weekend and inspected it. It still looks great and it has lots of rough landings under it's belt. I am thinking supplier/manufacture quality control issues maybe??
Those who pound their guns into plows, will plow for those who do not.
I am curious about what this bolt was torqued to. Strange as it may seem, when a bolt is used in cyclic load like the tailwheel bolt, the higher the pretensioning in the bolt (torque value), up to a point, the less likely it is to fail under an impact load. You therefore would want to pretension the bolt to it's maximum tension allowable.
According to the 43-13 page 7-6 an AN7 bolt used in tension should be torqued to 840 inch-pounds. That is 70 ft-lbs.
There was interesting article concerning this by Vance Jaqua (1929-2006). I believe it was in Vintage Airplane. At any rate I have the artlcle if anyone wants further explanation. Any good Mechanical Engineering Design book will have a mathamatical based explanation.
Before you can apply engineering of high quality bolts you need to employ one. More so with an eye bolt. The tail wheel is affixed with a tension load on the bolt and the eye puts a leveraged shear load on it. Not rocket science but not Home Depot stuff, either.
Last edited by sierra bravo; 07-11-2012 at 02:08 PM.
You mean a grade 2 eye bolt from Home Depot is not the correct bolt?Originally Posted by N5126H
It's an ABW part I got from Bush wheel Bill at New Holstien 3 or 4 years ago. I talked to Bill about it before I found the bolt and eye. I couldn't remember if it had a lock nut or a castle nut with a cotter pin, so we both thought it was a lock nut and the nut backed off. I'll take it with me to New Holstien maybe he can tell me something. I'm not knocking the part it's probably just a freak thing. I already ordered a new eye bolt from ABW. The biggest pain in the a$$ was covering the bottom 1/3 of the rudder.
Tim
Probably the 500 hard landings before it that did it in
Piper J-5A C-90 N40877
J-5 Project Pictures
Lucy you're gonna have to splain that better...
Last edited by OLDCROWE; 07-11-2012 at 07:47 PM.
"Illegitimis non carborundum"
As I recall the bolt goes through two leaves of the spring, one is slotted, which suggests to me that normal spring/reflex action is meant to occur during a landing with this slotted spring section. If it is supposed to be torqued to 70 ft lbs I have to go make an adjustment. Jim
tail_ski_crop.jpg
An alternative is to use a standard AN bolt of the correct length and an eye-nut as shown here. This is a forged and plated nut designed for lifting with a lock washer.
"They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety." Benjamin Franklin
I have a bolt that looks just like that. Broke on he way home from Lock Haven. Clean break bolt not bent. no gouging on the side showing signs of being loose.
Most embarrassed part of mine was I had just conned the waitress at the airport to go for a ride. As she walks out she said if she sees any baling wire or duct tape she wasn't going.
Taxi 10 feet and the tail wheel falls off. Up walks Patrol Guy and says I will take you for a ride while they fix that airplane. Could of swore that it was sabotage. I am going back to using the standard AN-7 bolt and replacing it yearly, as I did before.
166.JPG
167.JPG
168.JPG
169.JPG
I have that ABW eye bolt in my tailwheel. When the A/C is tied down the eye may present a bending moment on the top of the bolt if you were in a high wind situation. Other then being tied down the bolt is in tension.
Cant recall my airplane being tied down in any strong winds since I installed the bolt. Does have 800 or so landings on it. Might of been a couple of hard ones in there. Its a lot easier to replace a $1.50 every year than a $40 eye bolt. I have been greasy before.
Thats where the eye bolts in question were located
The difference is this is an eye-nut, not an eye-bolt. With an eye-nut you use standard AN bolts.
"They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety." Benjamin Franklin
Ok was just looking at the photo and missed the eye nut part.
Mr. Pierce,
I wasn't disagreeing with your statement about AN bolts. I was pointing out that it may not apply to a Home Depot quality bolt. Some bolts are excellent for tension loads and fail quickly when in shear. Some are better in shear and fail in tension. A Cub tailwheel eyebolt would need to be good for both. A Cub's tailwheel bolt is always in tension. The introduction of a lateral force from the eye is an unusual force, even for eye bolts. The only engineered eye bolts I know of are lifting eyes. I have no idea what lateral loads they test for but I know for sure they can take more than my PA-12 can dish out. High quality forged and machined convention style eye bolts are also available. I have no knowledge of what ABW sells and as I said before I really don't have any interest on my PA-12. The XP bolt on my Cessna is definitely higher quality than the average eye bolt and it was approved by the STC'd XP installation docs. It has seen plenty of wind and it's been perfect. In that installation the bolt's strength is in shear.
It probably has little bearing on the two broken bolts in this thread since I doubt either plane has seen enough wind to create enough stress to worry about. Must be something else. Spinner has shown the best solution in any case. That some won't pony up $10 to install a quality part on an airplane? That's beyond me.
Last edited by sierra bravo; 07-11-2012 at 06:22 PM.
Stewart, good point. I didn't get what you were saying in your first post. Makes perfect sense now. Never thought of that. Talked to Bill Duncan about this today and the manufacturer is being made aware and the failed bolts are going to the metallurgist. Will be interesting to see what is found.
Dan, where do you get the eye nuts? I'd like to see a more close up picture of them.
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
Good cheap insurance there!
Yes, some close ups of that and a source please!
I broke a standard AN -7 bolt in the same place. Probably was original equipment. That is a high stress application- sooner or later another one will break. I bet the BW bolt is as strong as an AN-7.
One can get MS bolts - same weight, but 167,000 psi. Changed my Decathlon over to them - cost upwards of 30 dollars per bolt. ACA offers them for over a hundred each.
Opinion.
Tim:
I had a ABW eyebolt fail while in FL this past winter. Messed up the bottom of my rudder as well, the old boy where I had it hangared fixed it while I came back to Maine. Mine pulled the nut off the threads. I did taxi thru a tortise hole I didnt see in the pasture I landed in. It wasnt a big hole, and really didnt make a huge bang. The eyebolt was 3 yrs old. I sent it back to ABW hoping for a new one, but I had to buy a new one, $40. Looks like with you and Bill T that makes 3 failures. Seems like something going on metal wise. I have a spare AN bolt in the back seat now.
Jim
Eyebolts that are used for lifting Cessna's are very strong and tough. I have seen them bent over(!!!) and not break, and still hold a load. I've heard of an old one failing.....corrosion the cause.
Love to hear what comes of the issue at hand. Bummer!!
I'm taking my Bushwheel bolt out tomorrow -- would be nice if the Bushwheels folks would post here and tell us what they know about this problem.
When a prang seems inevitable, endeavor to strike the softest, cheapest object in the vicinity, as slowly and gently as possible.— advice given to RAF pilots during W.W.II.
http://www.grainger.com/Grainger/ecatalog/N-1z0dr6z
http://www.hanessupply.com/content/c...002_200603.pdf
A couple of sources that I found for the eye nuts
Last edited by btracy; 07-11-2012 at 09:28 PM.
Bill,
Still waiting for pictures of the waitress.
The Bolts and BW eye bolts both break. Most people torque that little bolt way too loose they wear out then break.
If you never want the tail wheel bolt to break then take out that little bushing or "spacer" as they call it. Drill the tail spring hole larger or file it. Install AN-8 bolt. That sucker will NEVER break.
Daryl, I talked to Bill Duncan about this yesterday and the manufacturer is being made aware and the failed bolts are going to the metallurgist. Wup is on jury duty all week, Nicole nor Bill had heard of any other issues. They are concerned and looking into it by talking with the manufacturer and requesting the failed bolts to test.
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
Will an AN-8 bolt fit through the Scott? That sounds like a good idea
A Scott 3200 tailwheel has a 1/2" hole that uses a bushing to neck it down for a 7/16" bolt. Rallyer is talking about leaving the bushing out and enlarging the hole in the spring to 1/2" to allow a 1/2" bolt to be used.
I wonder if some of the breakage issues may be related to the bushing being omitted?
What about drilling the bushing out to 1/2 inch also, and leave it in there?
The bushing is 1/2" OD x 7/16" ID. Drilling tail springs is way fun.
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
any bets that Bushwheels WUP some bolt manufactures fanny?
(couldn't resist)
If Bushwheel guys are asking for parts back to test, my bet is that in two months or three at the outside, this conversation will be ended with the truth, and a solution. I have that much faith in their company.
I don't know where you've been me lad, but I see you won first Prize!
No worries, confident of a rapid resolution.
"Illegitimis non carborundum"
Took my tailwheel off again this morning, The Scott has a 7/16th hole, not 1/2 inch, the spacer has a 1/2 inch hole and the spring needs to be ground, filled or drilled out to get a 1/2 inch bolt in it. The Scott is aluminum that could be easily drilled to 1/2 inch. I think a 1/2 inch bolt and an eye nut would be the best you could get..
Steve what did you use to get a 1/2 inch hole in the spring? I know a torch will do it.
After rereading this thread I see there is a bushing in the Scott, I didn't look for that, I just tried to put a 1/2 inch bolt in there and it wouldn't go. Read and learn
Last edited by Tim; 07-12-2012 at 10:58 AM.
Posting Permissions
Reply With Quote
Bookmarks