Stronger Bottom shaft for Winters Extremeliner.

[Gman]

You beat me to it Mike, but oh so true. Cue the Karen Carpenter, Bob.

[Interested Observer]

Rob,
Although you have probably already done it, calculating the torque required on the shaft to take it fully plastic, as it appears has happened on the failed shaft, I get 1800 lb-ft for the 1.06" section and 2740 lb-ft for the 1.22" section, assuming a material yield of 120,000 psi.  This is still less than the 1300 x 2.48 = 3224 lb-ft that you cited as possibly being available.  Perhaps some attention would be needed to the heat treatment, if any, and the resulting strength and ductility. 
I agree with the need to get at least a hardness test of the failed shaft to establish a baseline for what Winters is supplying.  They are clearly not utilizing the capability of the material, and may just be using 300M so they can say they are using this (more exotic and high-falutin') material as a sales point or to justify a price.  And, it is doubtful that they would want to really heat treat it up very far because then they have to machine the splines in a hard, tough material.
I also agree with Rex' and Fordboy's comments with possible exception to the surface roughness.  Until the material becomes markedly less ductile, the surface condition has little to do with the failure.  It has just been overloaded and suffered gross plastic deformation.  Surface condition plays a more important part in fatigue loading and/or more fracture prone materials.

[manta22]

In instances where there are shafts that take considerable torque, I like to paint a black line along their length so that any permanent deformation can be clearly seen. If the line is still straight the shaft didn't twist into its yield (plastic) region.


Regards, Neil Tucson, AZ

[fordboy628]

In instances where there are shafts that take considerable torque, I like to paint a black line along their length so that any permanent deformation can be clearly seen. If the line is still straight the shaft didn't twist into its yield (plastic) region.


Regards, Neil Tucson, AZ

x2

We used to paint a white line on the black drive axles of the enduro cars.     Same idea, different color scheme.


Fordboy

[robfrey]

We settled on C300 Vasco material. It appears the maraging steels are the way to go for this application. We can expect a minimum of 275ksi yield. The stuff is over $20 a pound. I bought enough to to make 3 shafts plus a setup piece.
Delta Gear / Delta Research will be manufacturing the shafts. These guys are really good and their shop and equipment are top notch. The shop is so clean,  not only could you eat off the floors, you could eat off floors anywhere in the whole facility.
You can see more at their website. I visited the both facilities in Livonia, MI.  I left speechless.
www.delta-gear.com

[manta22]

Rob;

The maraging steels also have an advantage in that they undergo very little heat- treating distortion.

Regards, Neil  Tucson, AZ

[robfrey]

We received the new shafts from Delta Gear yesterday and they look FABULOUS!

The quality of Aerospace work usually surpasses the quality of work done for the average racer. There is a reason why aerospace parts are so expensive.
The pictures show a comparison between the Hobbes original and the ground aerospace version.

Rob Freyvogel

[robfrey]

Painted black stripe on shaft and we got it installed last night. We also developed and documented the shaft change procedure.

Notes to replace bottom shaft.
1) loosen parachute mount and remove bottom bolts. Lift out of the way.
2) Remove button head cap screws for flap pivots.7/32 Allen and 9/16 wrench
3) disconnect parachute cable from latch.
4) remove the five 3/8 bolts from the stinger to the rear end.
5) lift stinger up and out.
6) remove rear end quick change gear cover (catch oil)
7) remove driveshaft
Remove yolk
9) Remove shaft through back of rear end. (Knock out from front)
10) using the extend a magnet. Fish magnet through from front of rent all the way through the rear bearing.
11) slide snap ring retaining ring through the rear bearing over top of the magnet stick.
12) stick a magnet to center of new bottom shaft.
13) slide shaft into rear end from rear keeping magnet on end of shaft.
14) as shaft approaches bearing. Person in front of rear-ended will need to finish the ring on to the end of the shaft.
15) finish sliding shaft home.
16) reinstall yolk using sealant.



Rob Freyvogel

[ronnieroadster]

Painted black stripe on shaft and we got it installed last night. We also developed and documented the shaft change procedure.

Notes to replace bottom shaft.
1) loosen parachute mount and remove bottom bolts. Lift out of the way.
2) Remove button head cap screws for flap pivots.7/32 Allen and 9/16 wrench
3) disconnect parachute cable from latch.
4) remove the five 3/8 bolts from the stinger to the rear end.
5) lift stinger up and out.
6) remove rear end quick change gear cover (catch oil)
7) remove driveshaft
Remove yolk
9) Remove shaft through back of rear end. (Knock out from front)
10) using the extend a magnet. Fish magnet through from front of rent all the way through the rear bearing.
11) slide snap ring retaining ring through the rear bearing over top of the magnet stick.
12) stick a magnet to center of new bottom shaft.
13) slide shaft into rear end from rear keeping magnet on end of shaft.
14) as shaft approaches bearing. Person in front of rear-ended will need to finish the ring on to the end of the shaft.
15) finish sliding shaft home.
16) reinstall yolk using sealan


Rob Freyvogel

  Very similar to the steps I took a number of times when I broke the Halibrand lower shaft on my street roadster. After reading of your adventures with the shaft failure I now carry a spare with the race car parts just in case.   

[robfrey]

We went to the dyno to test a bunch of new stuff on the car. It was a good thing we did as we had a boost controller failure. We got to the bottom of the problem but not before we made 28 psi of boost at about 5000 rpms in first gear. I'm conservatively figuring we subjected the new Delta Gear bottom shaft to 4500-5000 ft/lbs of torque. Worst part is we were stupid enough to do it twice before we figured out what was wrong. The shaft hung in there fine but will confirm continue of shaft sometime over the weekend as I will remove it for inspection.


Rob Freyvogel

[Rex Schimmer]

Well that is one hell of a test especially when it was not intended and then to do twice just to make sure!!!

Rex

[jl222]

We went to the dyno to test a bunch of new stuff on the car. It was a good thing we did as we had a boost controller failure. We got to the bottom of the problem but not before we made 28 psi of boost at about 5000 rpms in first gear. I'm conservatively figuring we subjected the new Delta Gear bottom shaft to 4500-5000 ft/lbs of torque. Worst part is we were stupid enough to do it twice before we figured out what was wrong. The shaft hung in there fine but will confirm continue of shaft sometime over the weekend as I will remove it for inspection.


Rob Freyvogel

  Rob...How do you keep the tires from spinning on the chassis dyno?

                     JL222

[WOODY@DDLLC]

Well that is one hell of a test especially when it was not intended and then to do twice just to make sure!!!

Rex

Once an accident, twice a coincidence -third time they're doing it on purpose! 

[robfrey]

We went to the dyno to test a bunch of new stuff on the car. It was a good thing we did as we had a boost controller failure. We got to the bottom of the problem but not before we made 28 psi of boost at about 5000 rpms in first gear. I'm conservatively figuring we subjected the new Delta Gear bottom shaft to 4500-5000 ft/lbs of torque. Worst part is we were stupid enough to do it twice before we figured out what was wrong. The shaft hung in there fine but will confirm continue of shaft sometime over the weekend as I will remove it for inspection.


Rob Freyvogel

  Rob...How do you keep the tires from spinning on the chassis dyno?

                     JL222

We Carbinite the rollers. In fact we are doing two dynos for Ford on July.

[Tman]

Well, Rob. What parts blew in the rear end this time around? Bummer