Landracing Forum
Tech Information => Steering - Suspension - Rear End => Topic started by: robfrey on March 15, 2016, 12:19:46 AM
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I have designed a new bottom shaft that will be made from 300m. It should be about 51% stronger than the 300m offered by Winters.
If you want one, let me know and I will increase the order qty. They will be about $1000 a piece. If we get more orders, they will be cheaper. I'm having (3) made for myself. The stock shafts are only 1.062" diameter in the narrowed "flex" section. Our shafts will be 1.220" diameter in the narrow section. I believe the 1.062 diameter was chosen to clear the ring gear on the 4.86 champ rears.
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Rob,
I am just curious, did you happen to break the original shaft? Reason I am asking is that by increasing the size by 51 percent will the shaft still be able to have some torsion? I was told that was the reason Q-C manufacturers sized the bottom shaft the way they do.
Tom G.
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Rob,
Are you increasing the dia because of stress? If so what is your calculated stress? I agree with Tom regarding one of the purposes of the small dia is to attenuate shock loads between the input and the change gears and the ring and pinion.
Rex
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Yes, there will still be a necked down and it will be the smallest section but not nearly as small as original. New shaft design should be 51% stronger not 51% bigger.
Yes. We did break the original shaft rather easily.(http://uploads.tapatalk-cdn.com/20160317/cf43915b63a6a57715a52b8287f95d9c.jpg)(http://uploads.tapatalk-cdn.com/20160317/d6f636e7f673404865bf88648712ecdd.jpg)
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I also have very long axles that should also help with the transient torque spikes.
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Yes, there will still be a necked down and it will be the smallest section but not nearly as small as original. New shaft design should be 51% stronger not 51% bigger.
Yes. We did break the original shaft rather easily.(http://uploads.tapatalk-cdn.com/20160317/cf43915b63a6a57715a52b8287f95d9c.jpg)(http://uploads.tapatalk-cdn.com/20160317/d6f636e7f673404865bf88648712ecdd.jpg)
Ugh...those pictures bring back memories of a long 2 days in a hot dry dusty world!
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Just for $hits and grins do you happen to know the hardness of the failed shaft? The failure is characteristic of a ductile material torsion failure, normally if the material is heat treated to a fairly high level and therefore more brittle the failure in torsion has a 45 degree failure path. Maybe the stock shaft needs a better heat treat. 300 M can certainly be taken to hardness in the 40-50 Rc area without problems of being to brittle. The difference in tensile strength between Rc30 and Rc40 is about 25%. BTW what did Winters have to say?
Obviously going to the larger shaft will probably eliminate the shaft failure but may just move it to a different spot. And you do have long axles which should help attenuate shock load for the drive train.
Rex
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Rob,
Thanks for the pictures and information. Sorry about the mistake of 51% bigger instead of stronger.
Do you know if the bottom shaft in the Extremeliner is the same as the Champ style Winters makes except for the larger diameter and more splines for the Q change gears? If not no problem as I can call Winters and ask.
Rex has some good questions.
Tom G.
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Just a comment, pictures are deceiving.
Be careful the shaft increase in size does not get larger than the root of the smaller splines.
You may have to work on that also.
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After seeing the picture of your two piece lower shaft it brought back memerys of a similar experiance I had a few decades ago in my roadster. Just for the hell of it here's the short story about my lower shaft failure. After breaking the lower shaft in my Halibrand I changed to a stronger one next failure was the ring and pinion fixed that problem with a ring gear snubber next I found the input shaft on the four speed was now twisted next point of failure after input I think would have been the crankshaft. Good times doing this back yard hot rod stuff. :-D
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With the injected Chevy in my street roadster, along with the Hydramatic/early V-8 torque tube Cyclone quick change, I kept over 30 lbs. of air in the rear tires at all times. That didn't eliminate breakage, but it cut it down. I bought a Parilla motorcycle to drive to work when I broke the roadster or when it rained. Took the front fender off, too. Just as bright today, unfortunately, as I was then.
Stan
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Just for $hits and grins do you happen to know the hardness of the failed shaft? The failure is characteristic of a ductile material torsion failure, normally if the material is heat treated to a fairly high level and therefore more brittle the failure in torsion has a 45 degree failure path. Maybe the stock shaft needs a better heat treat. 300 M can certainly be taken to hardness in the 40-50 Rc area without problems of being to brittle. The difference in tensile strength between Rc30 and Rc40 is about 25%. BTW what did Winters have to say?
Obviously going to the larger shaft will probably eliminate the shaft failure but may just move it to a different spot. And you do have long axles which should help attenuate shock load for the drive train.
Rex
I think the old shaft was only about 30Rc.
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Just a comment, pictures are deceiving.
Be careful the shaft increase in size does not get larger than the root of the smaller splines.
You may have to work on that also.
Yes. New "small diameter is 1.22" dia and minor dia of splines is right about 1.300.
Snap ring dia are about 1.286".
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Just a comment, pictures are deceiving.
Be careful the shaft increase in size does not get larger than the root of the smaller splines.
You may have to work on that also.
Yes. New "small diameter is 1.22" dia and minor dia of splines is right about 1.300.
Snap ring dia are about 1.286".
Rob, If I were you, I would talk to Winters about this first, heres why;
I am not going to dig up formulas, only share what I see.
The main shaft reduced section is to absorb the torque in a place away from the circlip grooves.
The reason for this is that the circlip groove is very short and makes a very concentrated stress riser.
The difference in size between your new shaft and the groove is only about 0.033 per side. I may be wrong, but I would expect the shaft to break there next.
Now, if there is a way to eliminate the circlip groove, you could get the larger dia to live.
Best of Luck and keep us informed, John
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John, it's obvious you know what you're talking about. I have adjusted the 1.22 diameter so that it "goes red" on FEA the same time that the snap ring grooves and the minor dia of splines do. The shaft will still torsion twist at the 1.22 dia a few degrees at max torque. I may actually adjust it to 1.20 dia to make sure it is the weak link.
Even then, 1.20" is substantially stronger than 1.062".
Vaughn Winters is convinced that the material change alone has solved the problem. He said that nobody has broken one yet. My math says the problem is not solved. We can put down way more torque than anybody else in low gear. Even with these changes, I will have to limit low gear boost to 11 psi to keep crankshaft torque under 1300ft/lbs of torque as it will be multiplied by 2.48.
Winters will not be paying the $5000 plus bill to get our car and team back in forth to the salt never mind the heartbreak and labor of fixing it or worse yet a spoiled back up run.
I offered to pay for a run of these shafts to be made with an increased torsion section and an increased relieved section behind the QC splines (increased to minor diameter). They couldn't be bothered. We are in the meat of race preparation season now so they are crazy busy. I was a little upset that they would not share the spline information so I could have someone else make them. It's not a big deal as I can reverse engineer them but why make it hard for me. It's not like I'm not buying their stuff.
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Rob it would seem to me that it would be hard to apply that much torque to the driveline without excessive wheel slip in your lower gears. If you are looking at salt or dirt, both have a low traction coefficient. Pavement venues might be a little short for you.
:cheers:
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Rob,
Since you are modeling this up, have you tried gundrilling the center out?
John
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I'll throw in my 2 cents just because I have too much experience with drive train failure.
Two common causes for failures like this is fatigue and drive train shock loads. I'll say it is unlikely fatigue in this instance based on my experience. The steady state loads (simple engine torque calculation) are seldom as high as the peak loads due to wheel slip then grab, intermittent engine misfire etc. The peak loads from these is not due to the tire to wheel friction but due to the drive trains attempt to speed up or slow down its rotating mass in a portion of a second. This torque spike breaks stuff and designing in some rotational flex is a way to stop the short duration spike from breaking things. Sizing up the broken part is a good possibility but the risk has been discussed. There is no doubt that your driver is TOP NOTCH but I would suggest to try not to run the engine at full load in lower gears. Then when the peaks happen they may not break things. Also do anything reasonable to eliminate peaks like misfires or power shifting since it first has to accelerate the drive train then the car. This going gentler on the drive train may not be a possibility when going for records.
It's great that you are able to look at this with FEA and I think your approach is spot on. Yes it might move the failure to something else but predicting this is very difficult.
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Rob,
You may want to give G-Force transmissions a call. They offered to make a custom lower quickchange shaft for my oddball application. I think they make standard winters shafts already. Very nice guys to work with, they also do REM polishing in house and make their own quick change gears.
May be worth a call.
Andy
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Rob it would seem to me that it would be hard to apply that much torque to the driveline without excessive wheel slip in your lower gears. If you are looking at salt or dirt, both have a low traction coefficient. Pavement venues might be a little short for you.
:cheers:
By the time we get to 5000 rpms and the meat of the torque curve, we are making approx 2500 lbs of down force. Our car is very different from former efforts. I don't think anybody can load (steady state torque) a rearend as hard as we can in the lower gears. Even the high hp four wheel drive cars are dividing their torque between two differentials.
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I'll throw in my 2 cents just because I have too much experience with drive train failure.
Two common causes for failures like this is fatigue and drive train shock loads. I'll say it is unlikely fatigue in this instance based on my experience. The steady state loads (simple engine torque calculation) are seldom as high as the peak loads due to wheel slip then grab, intermittent engine misfire etc. The peak loads from these is not due to the tire to wheel friction but due to the drive trains attempt to speed up or slow down its rotating mass in a portion of a second. This torque spike breaks stuff and designing in some rotational flex is a way to stop the short duration spike from breaking things. Sizing up the broken part is a good possibility but the risk has been discussed. There is no doubt that your driver is TOP NOTCH but I would suggest to try not to run the engine at full load in lower gears. Then when the peaks happen they may not break things. Also do anything reasonable to eliminate peaks like misfires or power shifting since it first has to accelerate the drive train then the car. This going gentler on the drive train may not be a possibility when going for records.
It's great that you are able to look at this with FEA and I think your approach is spot on. Yes it might move the failure to something else but predicting this is very difficult.
We do "lift to shift" to avoid transient torque spikes and our high down force that we achieve even in lower gears keeps the drive tires on the ground much better than most. Long rear axles also help to absorb transient torque spikes that occur when and if tires leave the ground.
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Rob,
Per your previous post, Winters said: "Vaughn Winters is convinced that the material change alone has solved the problem. He said that nobody has broken one yet. My math says the problem is not solved. " From this I would assume that Winters changed from some previous material ( my guess would be 4340 aircraft quality steel) to 300M. 300M is nothing more than a very high quality 4340 (it does have some additional vanadium and silicon) that has been double and sometimes triple vacuum remelted in an inert atmosphere. The strength properties are effectively the same as 4340, the advantage that 300 M brings is its purity provides extended fatigue life. which allows it to be used in smaller sections, i.e. lighter, at higher hardness levels and still provide sufficient strength and fatigue life. I my way of thinking Winters has not done a sufficient job of properly applying this material. Normal use of 300M is at tensile strength levels of around 280,000 psi which is provided by hardness of around Rc 50-52. At Rc 30 the tensile strength is approx. 140,000 psi so it is possible to literally double the strength of the shaft at the same dimensions by merely doing a correct heat treat and draw. Obviously the advantage of going to a higher heat treat it that you do not have to increase the shaft diameter to get sufficient strength and you will still have the same amount of shock attenuation (shaft wind up) as the standard shaft.
Heat treat should be done in a vacuum or inert atmosphere oven and the shaft must be hung vertically. You must use a very reparable heat treat facility with experience with 300M.
I would highly suggest you contact some one like Latrobe Steel, Latrobe,PA and discuss your application and also what they would suggest for the proper heat treat and which one of their several 300M steels they would recommend for your application.
The other option if you are not going to heat treat and just go to the increased diameter would be to use aircraft quality (vacuum melted) 4340, normalized, which will have the same tensile and yield strengths as 300M but be considerably less expensive.
Rex
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John, it's obvious you know what you're talking about. I have adjusted the 1.22 diameter so that it "goes red" on FEA the same time that the snap ring grooves and the minor dia of splines do. The shaft will still torsion twist at the 1.22 dia a few degrees at max torque. I may actually adjust it to 1.20 dia to make sure it is the weak link.
Even then, 1.20" is substantially stronger than 1.062".
Vaughn Winters is convinced that the material change alone has solved the problem. He said that nobody has broken one yet. My math says the problem is not solved. We can put down way more torque than anybody else in low gear. Even with these changes, I will have to limit low gear boost to 11 psi to keep crankshaft torque under 1300ft/lbs of torque as it will be multiplied by 2.48.
Winters will not be paying the $5000 plus bill to get our car and team back in forth to the salt never mind the heartbreak and labor of fixing it or worse yet a spoiled back up run.
I offered to pay for a run of these shafts to be made with an increased torsion section and an increased relieved section behind the QC splines (increased to minor diameter). They couldn't be bothered. We are in the meat of race preparation season now so they are crazy busy. I was a little upset that they would not share the spline information so I could have someone else make them. It's not a big deal as I can reverse engineer them but why make it hard for me. It's not like I'm not buying their stuff.
Rob,
Per your previous post, Winters said: "Vaughn Winters is convinced that the material change alone has solved the problem. He said that nobody has broken one yet. My math says the problem is not solved. " From this I would assume that Winters changed from some previous material ( my guess would be 4340 aircraft quality steel) to 300M. 300M is nothing more than a very high quality 4340 (it does have some additional vanadium and silicon) that has been double and sometimes triple vacuum remelted in an inert atmosphere. The strength properties are effectively the same as 4340, the advantage that 300 M brings is its purity provides extended fatigue life. which allows it to be used in smaller sections, i.e. lighter, at higher hardness levels and still provide sufficient strength and fatigue life. I my way of thinking Winters has not done a sufficient job of properly applying this material. Normal use of 300M is at tensile strength levels of around 280,000 psi which is provided by hardness of around Rc 50-52. At Rc 30 the tensile strength is approx. 140,000 psi so it is possible to literally double the strength of the shaft at the same dimensions by merely doing a correct heat treat and draw. Obviously the advantage of going to a higher heat treat it that you do not have to increase the shaft diameter to get sufficient strength and you will still have the same amount of shock attenuation (shaft wind up) as the standard shaft.
Heat treat should be done in a vacuum or inert atmosphere oven and the shaft must be hung vertically. You must use a very reparable heat treat facility with experience with 300M.
I would highly suggest you contact some one like Latrobe Steel, Latrobe,PA and discuss your application and also what they would suggest for the proper heat treat and which one of their several 300M steels they would recommend for your application.
The other option if you are not going to heat treat and just go to the increased diameter would be to use aircraft quality (vacuum melted) 4340, normalized, which will have the same tensile and yield strengths as 300M but be considerably less expensive.
Rex
Rob,
After meeting you @ the PRI show and inspecting the broken shaft, my opinion about the failure remains the same. I still think that the shaft was overloaded and failed due to "machining" of the OD in the small center section. Without any inspection instruments, it appeared to my naked eye that the failure precipitated on the coarsely machined outer surface, a surface so coarsely machined, that it appeared to be "finely threaded". I suggested at the time that you consider a surface treatment such as surface "micro-polishing", in an effort to remove surface defects on any replacement part. My opinion remains the same. In the photo you posted, there is an obvious defect at the surface. I suspect that is where the failure originated.
After reading through this thread, I have some further thoughts. Some of this is, to me at least, stating the obvious.
1/ Trust your own judgment and engineering. I think you are in the best position to evaluate a solution using the recommendations of specialists.
2/ You might want to have the remains of the old shaft analyzed by a good metallurgist, even if Winters has given you a specification.
That would:
A/ Define the failure.
B/ Determine the material.
C/ Determine the material condition/heat treat. In my opinion these are important issues that need resolution, and the cost would be small.
3/ A material or size change alone will not solve the issue. It needs to be a comprehensive solution that includes heat treatment and surface finishing, as Rex has
suggested.
4/ Increased shaft strength will probably reveal the next weak link, as many have pointed out. It may be impossible to predict where that next failure will occur, unless
some part is "designed" to fail. I'm uncertain of whether designing a "failure link" is a good idea for your vehicle. It would be paramount to retain control of the vehicle
in the event of a drive train failure, again stating the obvious.
5/ Since the failure of this part requires so much "down time" for repairs, you are no doubt analyzing a solution that would prevent a repeat.
6/ It is always disappointing when a supplier becomes "uncooperative". But it is the nature of this business.
I hope you can at least get some "moral support" from the rest of us following along.
:cheers:
Mark
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Re: "We do "lift to shift" to avoid transient torque spikes"
Has anyone experimented with doing this automatically, like a micro-switch on the clutch linkage that retards the spark?
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Re: "We do "lift to shift" to avoid transient torque spikes"
Has anyone experimented with doing this automatically, like a micro-switch on the clutch linkage that retards the spark?
Yes.
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I'm wrestling with the universal problem of "giant torque spike after the shift with turbo". Just killing power comes in too late, and (from what I hear, no personal experience) the BOV capacity has to be near the engine displacement to completely save traction. This is pavement use at high boost with 4L80E, the transmission will take the shock but the tires won't.
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Re: "We do "lift to shift" to avoid transient torque spikes"
Has anyone experimented with doing this automatically, like a micro-switch on the clutch linkage that retards the spark?
So I'm supposed to LIFT at the SHIFT......... I didn't know... :-D
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I know this is off track but I thought I might talk about what actually causes the torque spike when you let the motor rev between shifts.
If we shift gears and let the motor rev, when we snap the clutch out the motor has alot of kinetic energy that it gives to the transmission, driveshaft and third member because they are tuning slower. If we shift from first to second at 8000 RPM and let the motor rev it's maybe goes to 9,000 RPM, but the input shaft to the transmission is maybe turning 7,000 RPM*. If we snap the clutch out, the different RPMs have to match within a portion of a second. This causes a large torque spike in the drivetrain. One of the things that determines how much the spike is, is how much the clutch slips before the parts are at matched speed. The faster they match the higher the spike. And this analysis does not even consider the engine torque being transmitted.
Of coarse we all know this is how we could make our six cylinder Ford Comet three speed chirp the tires.
* Why is this only 7000 and not the 8000 you just shifted at. Because when you shifted, the synchronizer slowed the input shaft down.
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Rob thanks for being a good sport while we all "solved your problems" from our easy chairs :roll:.
I do want to mention what I'm sure you already know and that is the affect of a shaft that varies in diameter such as due to coarse machining like Fordboy said. If this shaft acts like a torsional spring by wrapping and unwrapping based on changes in transmitted torque, there will be adjacent areas of the shaft that flex and next to it, it is more rigid. This will cause serious stress risers. If you still have access to FEA you might see what this does to a shaft that is under high enough torque for the alloy to go into elastic (not plastic) deformation.
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Re: "We do "lift to shift" to avoid transient torque spikes"
Has anyone experimented with doing this automatically, like a micro-switch on the clutch linkage that retards the spark?
So I'm supposed to LIFT at the SHIFT......... I didn't know... :-D
No, you don't have to. You have a substantial rearend.
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Re: "We do "lift to shift" to avoid transient torque spikes"
Has anyone experimented with doing this automatically, like a micro-switch on the clutch linkage that retards the spark?
So I'm supposed to LIFT at the SHIFT......... I didn't know... :-D
No, you don't have to. You have a substantial rearend.
Some might say He Is A Substantial Rearend! :-D
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You beat me to it Mike, but oh so true. Cue the Karen Carpenter, Bob.
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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.
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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
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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.
:cheers:
Fordboy
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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
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Rob;
The maraging steels also have an advantage in that they undergo very little heat- treating distortion.
Regards, Neil Tucson, AZ
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We received the new shafts from Delta Gear yesterday and they look FABULOUS!(http://uploads.tapatalk-cdn.com/20160526/61784e3dad513e1fff67183199b20793.jpg)(http://uploads.tapatalk-cdn.com/20160526/36ebcc06f56604b854b2341441cb6860.jpg)(http://uploads.tapatalk-cdn.com/20160526/272bec9938e28597c48932508f788a27.jpg)
(http://uploads.tapatalk-cdn.com/20160526/51f38633b155da34487026a54811766f.jpg)
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
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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
8) 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
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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
8) 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. :cheers:
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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
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Well that is one hell of a test especially when it was not intended and then to do twice just to make sure!!!
Rex
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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
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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! :-D :-o :-D :-o :-D
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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.
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Well, Rob. What parts blew in the rear end this time around? Bummer