Matt Mark­staller

CREW CHIEF AND TRI­UMPH IN­FOR ROCKET STREAM­LINER DE­SIGNER

Motorcycle News (UK) - - Features -

Did you pro­duce the power first?

We’ve run the tuned en­gines on a reg­u­lar dyno with them housed in a reg­u­lar Rocket, just like you would a con­ven­tional bike. Then again once on the chas­sis, with the two en­gines com­bined. We’ve run the Stream­liner on a spe­cial­ist car dyno, the long wheel­base wasn’t a prob­lem so we know the power and torque of the en­gines com­bined. We looked at chas­sis sim­u­la­tion to limit weave and wob­ble. We worked with Dynomo­tion in Italy who work with many of the Mo­togp teams. We can try dif­fer­ent sim­u­la­tions to get the bal­ance right, wheel­base and head an­gle, that way we know we have some­thing sta­ble us­ing al­go­rithms be­fore we go ahead for real.

Is it hard to bal­ance?

Balanc­ing the bike is rel­a­tively easy. We have 15lb of lead on the right side be­cause the Rocket en­gines are slightly heav­ier on one side than the other. The static bal­ance is rather easy to be hon­est. You want weight over the rear for trac­tion, but you don’t want the front to be too light as you need weight over the front for sta­bil­ity. Then it’s the aero­dy­nam­ics – which is the hard part.

So the faster you go the more sta­ble it is?

If I re­mem­ber right off the top of my head, the worst wob­ble comes in just over 100mph, then weave starts to creep in around 200mph or just be­fore. Once you are above 200mph it’s ac­tu­ally more sta­ble, ac­cord­ing to the com­puter.

So the dan­ger­ous part is run­ning at sub-200mph?

For sta­bil­ity you could say that, as once above 200mph you should have the sta­bil­ity but then once above 300mph ap­proach­ing 400mph you are then push­ing the me­chan­i­cals, tyres for ex­am­ple and the wind can be­come an is­sue – along with a thou­sand other things.

What is it like work­ing with Guy?

At first we were a lit­tle con­cerned as originally the Stream­liner was de­signed for a shorter rider and we were con­cerned he might not fit in, but he gets wedged in there. Guy is amaz­ing to work with he has no fear, he just wants to go for it. If we say ‘let’s go flat-out’ there’s no doubt he will go for it. Guy is used to road rac­ing, where you don’t have the best han­dling bike be­cause of the con­di­tions, jumps, bumps etc. Our bike isn’t the best han­dling, but Guy just jumps in and gets on with it. He is used to just go­ing for it. For some rid­ers it can take a week of prac­tice to ride past the weave and wob­ble – it took Guy 15 min­utes.

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