Salt flats?

[ClineDesign]

Anyone heard what's going on with George at the salt flats?

[John H]

George should be back tomorrow. The salt gremlins won this year. Bolts holding the cylinder down failed, maybe from the added boost. With that repaired, the ignition module failed and George was unable to find another one.
His friends from Australia, AAA racing was successful in taking Georges 100cc record so there was some celebration.
My friends from Sweden had a lot of teething problems with the new streamliner so will have to wait til next year for another attempt.
I traded a cargo trailer to the Swedes in exchange for their old Jawa powered land speed bike. It is officially retired after setting records in 350cc vintage class and 650cc vintage class.
I had a mishap while unloading the bike and now have a torn acl shoulder. That's the end of riding for this year.

Swedish Thunder.jpg (185.59 KiB) Viewed 33034 times

[ClineDesign]

Australian racing team Afflick - Afflick & Afflick - AAA Land Speed Racing Team set a 100cc Bonneville record 111.34 mph!



https://www.facebook.com/AAALandSpeedRa ... 310891781/

[salt-racer]

Hi Guys
Yes, the gremlins won this year!
During my second run, the bike went sour before mile marker #1. The rear two fasteners failed (again) on my cylinder adapter plate. I had thought slightly larger and higher quality bolts would have solved the problem, but I did raise the boost pressure significantly and that may have a major effect....hmmmm!
The final blow was ignition failure, and not having enough time to get parts (the nearest replacement CDI was in Connecticut)!

My Friends from Australia had a much better time. They successfully captured my 100cc record of 91mph and raised it to 111mph!! They steadily raised their speed as well as nitro content in their fuel until the motor started showing signs of strain. They did everything right! Congrats to their team, AAA Racing!

Next year..... the wheels are already turning!

George

[salt-racer]

Yes Jay, JP remembered that you wanted an authentic AAA Racing t-shirt and I brought it back with me with your name on it!

Ill catch-up with you at our next meeting!

George

[John H]

George asked me to post these photos. He will comment on them.

George BV.jpg

George Bv1.jpg

[salt-racer]

Well, here are a couple Pics from Speed Week 2017, thanks for posting for me John!
Top photo shows that although broke in the pits, we were still having fun!

Lower photo shows one of the fastener heads (we snapped off two) in the grasp of my fingers...... our plan for next year is to go to a larger fastener, 3/8"-24 vs. the 5/16"-24 we tried this season. The photo shows the steel adapter plate which allows the YZ top-end to bolt-up to my vintage KX125 cases (Kawa-Yama blown 125cc).

I firmly believe the motor was producing enough power to take me to my target goal of 130mph. Now, if I can only harness it?!

George

[ATinkerer]

Socket head cap screws are fairly brittle. Wonder if it failed in bending rather than tension?
Would think the aluminum case would flex enough to keep the forces axial, but if the failure is at the top thread interface it is a possibility. Slight misalignment between the cone centerline of the flathead and the threads can induce quite a bending moment if the fit is tight.

Gordon

[salt-racer]

Yes Gordon, you brought up a couple of very credible points. Misalignment and side load....and generally, flush head fasteners should not be used in critical areas because of the stress concentration on the first thread (says this right in the machinery handbook).
The cylinder adapter plate mount holes and the existing Kawasaki case threaded holes have to be in alignment otherwise a side load would be generated when the flush head screws where tightened. This misalignment would create a bending/shear at the intersection of the fastener taper and the first thread. Sure DEATH!
After the first failure of the bolt/screw heads, I setup the entire engine in my milling machine a drilled-tapped-helicoiled-kissed the countersink surface in one operation to ensure alignment. This should have verified the alignment of the plate bores to the case bores. Also, the Holo-Krome (USA) fasteners specify/guaranty the concentricity of the threaded shank and the tapered head.
After all this preparation, the new fasteners failed with less than two runs. It's also weird that its always the two rear fasteners that fail.

Flexing of the plate is the next possibility we are considering.... but I don't know of any way to stiffen-up the plate. I can't thicken it without machining/weakening the mounting ears on the cast aluminum cylinder.

So without any other bright ideas, I plan on going to bigger screws, and hoping that they will survive in this less than perfect design. The fasteners are certified high strength aircraft hardware NAS 1102 CRES, stress relieved and special round rooted threads (UNJF) and a bargain at $10 each delivered.
Wish me luck....
I hope SIZE matters!
George

[ATinkerer]

You already thought of every thing I came up with. The answer has to be somewhere in the alignment and fastener elastic deformation curves. Larger, but not as high a tensile strength (more elastic) may be the answer as you suggest.

Gordon