Rex, as usual, you are on the money.
From DEAN in LA:
While we are anxiously awaiting today's post, I have a question.
On a vehicle that goes this fast, rear end alignment is critical.
What method was used to align the front and rear end in yaw and roll?
Comment from PETER JACK who is ruled by a dog:
These guys are way too good on the mill to have the splines ending at random distances. I'm thinking that the reason has to do with not providing any sort of a straight path for fractures or twisting. How's my thinking?
From INTERESTED OBSERVER:
Since the Greek couplers still interface with the original splined shafts, what was the point of replacing the original sleeves?
Although it is more of an issue in a fatigue application, the raw-cut spline grooves without surface treatment and shafts without stress relief grooves at the spline ends would be a concern. Hard to say without knowing the stress levels.
Here is the reply from Marlo regarding these recent questions.
In a nutshell, there is a straight line from the center line of the front and rear drives that was established with a machined line up bar. It went through the main bearing bores on the blocks and supports. The side shafts are parallel with that line and the pillow blocks are shimmed to keep that alignment. Yes, the Greek couplers are still on the original shafts but, the shafts are multi piece and to compensate for any twist or yaw in the chassis, the Greek couples have several degrees of latitude and are self centering. The coupler sleeves that I had made originally have NO ability to allow any misalignment without binding on the splines. There would have been no reason to have the Greek couplers in all of the joint locations, but, by doing all locations, no matter where twist or torque may effect the shaft position, the Greek coupler can take the mis-alignment and not bind on the splines. It acts like a very small direction change compensator. The Greek couplers that did not fit the splines were machining anomalies (from Mark Williams) and not a reflection on the splines that were cut on the shafts. The ones Strasburgs made fit fine. All of the shafts that Mike Swick made for me,( refer to Unsung Heros section from the front page. editor) I personally put couplers on before I took them to Jim. The reason that the shaft had to be straightened was that the material was heat treated and had some bow in it from the heat treat that we were not aware of. Mike just cuts the shaft to length, puts centers in both ends and machined the splines with an indexing head, so the shaft never is rotated other than a few degrees at a time. There was NO reason to suspect that the shafts had runout or we would have corrected that here. The runout in the middle of a 36 inch shaft translates to a few thousanths at the end after it is put in pillow blocks. Until all the pillow blocks were in their final location, that was not an issue. I built the belt drive boxes with identical center lines but, the shafts that connect them are multi lengths. No shaft is over 34" long without supports. 36" is the longest that size shaft can be and not have harmonics at 7000 rpm. By using shorter shafts and supporting them in the middle we run the harmonic rate up to 10,000 rpm+.
The pillow block, shaft, and coupler alignment could not be completed until all of the welding on the chassis hard parts was finished. That is why it is being done now. There are no large welds remaining to complete the chassis.
More than likely, we will have to address the side shaft alignment again after the car has some cycle time. There is no way that is will stay in perfect alignment. It will stress relieve itself somewhat. However, the center line of the car will not be effected as much as the sides. The motors are mounted to bulkheads and the drive mechanisms are also well mounted. However, even though the motors and drive components should not move, by using the Greek couplers on those joints as well, we just buy insurance. Misalignment with a sleeve coupler would allow the end of the coupler to gouge the shaft and could lead to failure.
That is also why the body panels have adjustments, we will be able to correct the body alignment if and when the chassis decides what its final shape will be.
I don't know if that answers the questions. I think I may have gone overboard somewhat. We are just doing our best to be right the first time it runs and so the changes are being made to avoid premature ejaculation.
Yes, the splines on the shaft do not all end up the same length. That is another one of those things that makes the shaft not break at the end of the spline. Remember when a rear axle used to break in a Chevy? The break was always circular at the end of the machine area. It had created a stress line that became the fracture.
In the lakester, I used a Greek coupler between the output shaft and the rear end. That is a very short distance and there was NO drive shaft. The coupler gets worked somewhat, but the splines on the output shaft show no damage.
THANKS for the questions. When I don't have a definitive answer, I'll ask until I get one.
Things to look forward to:
The method of shaping the windshields.
The opening in the canopy for the windshield.
The completed torque tubes with the tops bolted in place.
The rear wheel fairings.
Finish welding on the chassis and the air test for leaks.
Rolling the chassis over to get access to some needed welding.
Building the outside tent so the chassis can be sand blasted. Winter is coming here and it rains every day.
Building the inside tent so the chassis can be painted. A retired fireman from the railroad will stoke the wood stove to keep
the heat correct: 24/7
Hume Cad v3.9 We have spies within Granite Falls HS Manufacturing Class. We will soon have access to their design software.
FREUD