356 Engine Dynometer

[Jbrooks]

Started winding coils, such joy, probably should have contracted this out to a motor shop. Anyway the math worked the coils came out the right size and resistance. They fit the hexagon like just like they were designed to fit. I have about 3mm clearance above and below for the rotors and cooling air. From the first pair mock-up, it inside of the coil carrier is going to be full of copper. Tested one at 12v under a sheet of paper covered in band saw dust, the magnetic field is larger that a sheet of paper.



I coated wire with liquid electrical tape as I wound the coils to help bond the coils as they were wrapped, ugly but effective. I will wrap them with KAPTON tape after I get them all complete and fit the hoders to the hexagon.

[Jbrooks]

Got the octagon welded up today, worked well came out within .004.




After that we checked the clearances for the rotors, right now that's about .300 from the magnet coils to he rotor, So I am OK here. Two coils laying in the bottom so I can measure the outside diameter to make sure I can get the most wire and retain clearance. Shows 8 degree right list, for the pivot point , the hexagon will be pulled down with rotation into the load cell.






image.jpg

Here is a mock-up of the mounting, There are two coils per section, I will fabricate the end caps for the coils. Here is just a pair of cores hanging on some scrap angle with a couple magnets to hole them in spot.



So far it all fits together like we planned. The Octagon is 1/2" fat bar, cutting and welding it, with out any distortion and keeping it square even surprised me. I was sure it would need to go on the mill for clearances, But some how the math worked.

Thanks for looking..

[Jbrooks]

Wednesday update. Wound the first coil 1.2 ohms about a pound of 18 AWG wire. Coil works as expected. Did a design change to the load. The original concept was to put a octagon coil holder around the IDA of the rotors, mount the could on top of some 1/2" thick flat bar. Mocked it up with wood, and decided to but the flat bar outside and hang the magnets under the hexagon frame. (Examples in the photo.) That makes it easier to mount and keeps the center of the magnetic fields inside the rotor, The outside steel flat bar will also help focus the fields. Since this part try's to rotate into the load cell it will have more clearance with the coil pack on the inside





I made the mock up hexagon from wood, thought it would be easier. Ever try cutting wood to +- .001, but it worked.

Here is a side view of the rotor with a coil core inside. This core will be wound with magnet wire, then a hanger bracket will be screwed to the ends that will attach to the octagon. The hexagon will need to pivot and I ma trying to keep a max of 0.250 clearances on the rotation and fixed components.

thanks for looking

[JTR70]

That is Fantastic, Thank you for your service! WOW, heavy duty tube sections you're using there; coming along nicely.

[Jbrooks]

JR

I am still out on Whidbey, did you not see the photo above your ameiia island photo. I posted of my 49GMC with the dead whale in the back? I have had mine sine 66.

[JR]

Thanks Roy for the 'heads Up'.
OK John where are you located now??
I am in Chester, VA just South of Richmond.
I have had 88971 for 56 years as of this October.
It is part of the family.
I was in VA-35 1968-70 witha WestPac cruise on Coral Sea 69-70.
Dick

[roy mawbey]

John, I have been following this and wow you are doing something quite special with the kit and money you are spending. Like most of us reading this, its principle is to a degree understandable but the manufacture and getting this to work is beyond me. I see you were involved on A6, a friend of mine Dick Pitman a friend of mine living in Virginia and the owner of a lovely 356 Roadster and who also posts on here, flew in the Navy A6 planes. He is a clever guy too and I will tell him to have a look on. I hazard to guess what a new dynometer would cost to buy but its got to be lot I reckon.

Thanks for the story so far and the photos! Hope it all works when finished!

Roy

[Jbrooks]

Got the strand frame glued together today . Everything still measures OK and the shaft spins easy. I can slide the engine in and out easy even with the extra rod going through to the rear bearing pocket So far so good. Back to the machine shop to fab the rotor carrier and the square up bearing holding blocks. Probably the first guy to ever make a test rig based on an" engine jack".

The load section is to the right of the engine. overall 22' wide and 24' long. It will probably get a little shorter after I get the coil pack located.






Here is a 911 run in stand that belongs to Chuck Allard, the inspiration for this DYNO. Chuck has a couple stands like this for different engines and races old porsches. . He just acquired an old Stu ska VW dyno, We are trying to see who get finished first.




Thanks for watching

[Jbrooks]

JR I am a retired Naval Officer and then ran a Fire Research LAB for a few years. I was an A-6 intruder guy, you learn allot keeping things in the air. This drag rotor load system will work similar to the EMALS catapult on the USS Ford. I just pick stuff easy and have no responsibilities or measurable goals.

Got all the alignment numbers dialed in. The pillow blocks are sitting on some 3/8" wall, 6" square tubing. I need to get them on the milling machine and parallel the top and bottom surfaces but it came out with in 0.0004 run out in alignment.

This photo is with C clamps in place for measuring. The shaft extends through all 5 of the carrier bearings. These will carry all he loads. The magnetic breaking disc will mount between the 4 pillow blocks. The aluminum disc shown on the shaft are the No#1 and #3 main bearings simulators. These allow me to shoot the center of rotation of the crank through the bell housing and into the pillow block carriers. The shaft spins easy with everything locked down,




Here it is rotating section with the engine case installed, drill Rod is through the case into the third member, its going to be pretty small overall, I think it will be about 3.5-4.0" shorter when I am done.. I need to place the coil pack and load cell in the center, then get the rotors attached to the main shaft. The shaft will be turned down with splines into a clutch disc. The rotor carrier is 3" in diameter 6" long and has a 1/4 broached and key to the shaft. Balancing this entire thing is going to be interesting, But I have a plan

[JTR70]

Are you an electrical engineer by trade John? I can't imagine putting all this together and actually having it work. Impressive to say the least.

[Jbrooks]

Thanks Scott, I hate math with Greek Letters in it, but it could be cheesiness arithmetic, you can do too, it its just hard.


Started the power supply and control units. I found a scrapped diode pack from an old welder. So I have a 0-60VDC power supply that should supply plenty of current. If it will weld it should drive a electromagnet. I an using up a bunch of left over stuff in the process. Also built a crazy complicated relay control for the coils. Since I am always over complicating things , this in addition to varying the voltages and the current for the load. I can change the number of energized coils and their clock locations. The theory says i need to pull on the disc equally to avoid trying to flex the shaft, I can control the loads so I should be able to program the dyno to climb hills and accelerate and decelerate, just like driving the car on a brake in.




Thanks for watching

[Scott B]

Some real fancy engineering going on here my friend - putting me to shame with all the slide-rule and math calculations and figures.

My math is getting rusty.

With the current pandemic situation - eating out is not an option - so I have not had to figure out a 15 or 20 percent tip in the last month.

[Jbrooks]

Got some parts in and more measuring. Turned down a tool to fit in the No# 4 main bearing in the third piece. It fits the case and the drill rod is centered in to to locate the rotational plane through the crank. Worked out pretty well. The height gauge say it good.




The tool holds the rod centered and let's me locate the center of the first pillow block on the bell housing. Fits up fine probably with in 0.001th" the height gauge.


Have the block located, the carrier plate made and the bell housing bolted together. So far it seems to fit. Next is to turn a carrier for the disc, cut a key way in the shaft and build up the carriers for the other bearing blocks. The shaft needs to be turned down and spline to match the input shaft on the transmission. I am debating using the clutch to drive the shaft, or making a plate that bolts up to the flywheel and extends into the pilot bearing.
If I use a disc bolts to the flywheel, i can use a simpler spline but will still need to extend it into the gland nut to reduce the vibration induced into the shaft

[Jbrooks]

Still awaiting parts, but I have been looking a commercial units and their specifications. Doing some math

I am building this based on a Telma retarder used on a F450 or MB Sprinter application. This Telma unit uses 6 coils in three stages , their coils are turned on in pairs, Mine has 16 coils in 8 stages, but I can change that after I get it together. The math says I may have over built it as usual. The numbers look good. All you need to insure is that you pair up the coils 180 degrees across the rotor, and stage them next to each other so the fields and interact. The below curves are adjustable by adding or re-configuring the coil packs at full voltage. I should also be able to adjust the torque curves and changing the voltage to vary the current, changing the magnetic fields, changing the loads. .

After it done I should be able to program the retarder control unit for each type engine. Say for a 616/xx I should be able to dial in the load specifically for the engine configuration. I may not be able to do a 930 turbo but who cares, this is good enough for what I expect to see.

[Phil Planck]

Impressive John. Hope it works as planned.