RailGun MkII - First Post

[mgriffiths]

This is the first posting for the Build Diary for RailGun MkII

I'm already a couple of months into the build - I started pretty much right after SpeedWeek.

This bike is built with my Beam N' Ladder aluminum extrusion architecture like the MkI so lots of pieces that I've made will fit right up.

I've moved the engine to the rear because it was too inefficient to transfer power from the front engine configuration.

I'm parking my nice EX500 power plant for another day, who knows, but for now I'm moving on to the 750 class with a GSXR powerplant.

I'm also committing to Methanol for the new bike, for the usual reasons, more power and it burns so cool.

And to continue from the good performance on the MkI I'm going to design and build the EFI system (Niagara), and for this year I'm also designing and building the Ignition System (SparkNado).

I've posted a few pics of the bike, and also here is a quick video of SparkNado being tested at 14,000 RPM

https://www.youtube.com/watch?v=ZRDzuUOeFmQ

Let me know if you have any questions or comments,
Cheers, Mike

[manta22]

Mike, the torsional stiffness of your chassis looks a bit suspect.

[mgriffiths]

Mike, the torsional stiffness of your chassis looks a bit suspect.

The two 1x2 rails are tied together to the 2x8 main backbone, along with multiple bolted cross members and the engine is a stressed member.  I've done the usual stress tests on the chassis and it performed very well at Bonneville last year.

What are your specific observations?

Cheers, Mike

[manta22]

It simply looks torsionally compliant- just my observation based on experience. Did you twist the chassis or just bend it in your tests?

The SCTA has comprehensive chassis construction rules for cars but I've never looked at the rules for bikes.

[mgriffiths]

It simply looks torsionally compliant- just my observation based on experience. Did you twist the chassis or just bend it in your tests?

The SCTA has comprehensive chassis construction rules for cars but I've never looked at the rules for bikes.

I'll post a few more pics to show some of the detail, but visualize the chassis as an upside down 'T', 11 inches wide, and 10 inches tall. When boxed in, it's incredibly stiff. Mike

[Interested Observer]

Like Manta22, my immediate impression upon viewing the first photos, and before he made his comments, was to be concerned about the torsional stiffness of the chassis.  While it is unclear how much stiffness would be desirable or necessary, the only thing providing any significant stiffness is the 2x8" center beam, and its capability is unclear--not knowing what the interior dimensions are.  Is it solid?  The two lower side rails are next to worthless for contributing to the torsional stiffness.  Also, bolted connections are likely a stiffness sink.