Vespa Dry Lake Racer lives...

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zork
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Re: Vespa Dry Lake Racer lives...

Post by zork »

Photo of the year GP, last weekend at PI
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internetscooter
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter »

That's why I have 30kg of lead for the glove box ;)
Paul
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DLRA #647
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter »

A few updates :)

Progressing with the CFD and getting to play with some major research tools at Monash University so I could submit the visualisations to the supercomputing conference I am going to in Nov... submitted the following and it was accepted to display on their vis wall during the event :)


Click here to learn how to add YouTube Videos to your phpBB forum

I will also be displaying the real Vespa here this weekend in Melbourne at the Oil Stained Brain motorcycle exhibition http://oilstainedbrain.com.au/

And supercharger is coming along...

Image

Image

The process now is measure and align things (I designed the bracket so it is tweakable) and finish the pulleys to suit.

I have a few more goodies hopefully arriving in the mail box this week, including an inline BOV (which should work a treat and look pretty cool too), air filter and negative pressure sensor for validating the CFD model (measuring that negative pressure zones appear where the simulation says it should).
Paul
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DLRA #647
89.664 mph (aiming for 100mph+)
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Johno Senior
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Re: Vespa Dry Lake Racer lives...

Post by Johno Senior »

Gooday scooterman,
Groovy work man ! BUT what I really rang for is You seem to have your head around this aerodynamic stuff, let me run a scenario past you for your thoughts on the matter.
I am running im MG or MF 750 so naked bike. I am well down the track of setting the bike up based on a chat witha US Bonny record holder in a smaller 250 class. he is saying everybody is going the wrong way by dumping the bikes ultra low when aero wise he has raised the hell out of his bike on 21 inch wheels , clean under motor etc.

it kinda made sense to me so I am giving it a go. Reason let the air go past all around the bike not just 3 sides meaning less overall resistance. I done some sketchs and it looked good to me so thats been my plan, then talking to my main class competitor and current record holder Finny about a front fender or not and he was saying he felt the airtech fender was priceless, so I contact air tech and they done do a front LSR fender for 19 inch wheels which I was going to use Z rated etc.
They only make them for 18 inch or 17 inch...........................so noone in the whole universe runs up high, big diam wheels with aero front fenders...............................Do you think I'm heading down the right track or up the creek with out a paddle .................................Scooter man or is that captain Aero ? .... talk to me.
cheers Johno
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter »

Unfortunately I am not an aero expert :( What I do know is that stuff I am doing only narrows down what I should be looking at - so far it has told me not to worry too much about aero this year as my limitation is my power curve not getting into the higher RPMs.

What my model is also missing is spinning wheels and that has an influence on things which I am not tracking.

What I do know is if you take an teardrop shape (which has low Cd) and stick it near the ground it Cd increases, so in that case being higher off the ground is better. So taller tyres "might" introduce a slight increase in frontal area but drop the Cd more. This change would be so small that I doubt a CFD model would predict accurately the difference (especially if it is not rotating the wheels as part of the simulation).

I dump some knowledge on Vespa Labs http://www.vespalabs.org/Projects/Vespa ... 2F3D_Model which may or may not help ;)

edit: Just to give some context - my background is in complex computer systems and visualisation, I am very weak on the mathematical modelling side and the CFD is a learning exercise to take me from very weak to just weak :)

Cheers,
Paul
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DLRA #647
89.664 mph (aiming for 100mph+)
www.vespalabs.org
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter »

Bugger :( I thought I was being really tricky sourcing an inline blow of valve which fitted straight to the carb... WAY too big though and I can not get the side panel on... back to the drawing board and I have a 2.5 inch inline BOV for sale if any is interested...

Image
Paul
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DLRA #647
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Team Waterbottle
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Re: Vespa Dry Lake Racer lives...

Post by Team Waterbottle »

Hi Johno
The best thing about Aussie LSR is doing it your own way. With a faired bike I feel ground effects are worthwhile considering to lessen the bike's uplift & this mainly comes belly pan design, low ground clearance & attitude. Also, ballast is an obvious consideration, but with an unfaired bike, frontal area is king. Standing the bike up will increase fronal area that's for certain. But it doesn't manner... do it your way & have a crack. I think you should put your bike high as possible... because I think it's wrong :wink: 8)

I'm still running with a Airtech front mudguard, but want to make my own as Airtech design doesn't take full advantage of the rules. We can discuss this further at Lushy.

I'm putting #1 engine together this weekend, I'll post some pictures for your dart board ! :lol:

Finny
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AuotonomousRX
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Re: Vespa Dry Lake Racer lives...

Post by AuotonomousRX »

Hey Paul

Even more intrigued with your build now that it's going to be a forced induction 2 Stroke. 8) 8)

It's been in the back of my mind for a while, but using a Turbo.

Are you going to maintain the Expansion Chamber?

Great Stuff

Pete :D
Still trying to decide if I am a procrastinator

Pete :?
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gennyshovel
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Re: Vespa Dry Lake Racer lives...

Post by gennyshovel »

internetscooter wrote:Bugger :( I thought I was being really tricky sourcing an inline blow of valve which fitted straight to the carb... WAY too big though and I can not get the side panel on... back to the drawing board and I have a 2.5 inch inline BOV for sale if any is interested...
It would make a GREAT ashtray :oops:
Tiny
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter »

Actually I am going to try and trim the BOV down :)

Induction 2-stroke only works with an expansion chamber - you get a bigger bang and the bigger bang produces a bigger shockwave to counter everything trying to escape.
Paul
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AuotonomousRX
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Re: Vespa Dry Lake Racer lives...

Post by AuotonomousRX »

Sorry Paul of course you are keeping the Expansion Chamber as it's Supercharging not Turbo, so it has to be used.

I asked because I have seen Turbo 2 Strokes with and without an Expansion Chamber mmm.

Pete
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter »

The trouble is that you have the inlet and outlet port open at the same time. So you have one side with higher pressure than the other and more fuel mixture would want to head straight out without contributing to the bang. This would be the same for a turbocharger as for a supercharger, in fact my knowledge is based on reading up on the turbo Vespa.

You'd probably get more power without an expansion chamber but my understanding is that you really want something to counter the effect of unbalanced pressure.
Paul
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DLRA #647
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter »

A bit of whittling with the lathe and it now fits :)

Image
Paul
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jpbyron
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Re: Vespa Dry Lake Racer lives...

Post by jpbyron »

Looking good mate. Not sure about those turbo or blown two strokes, how do you keep the crankcase seals in them .

Anyways blown fuel 100 is coming along nicely as is your build. 100mph here we come!
Motorcycle Racer Lake Gairdner & Bonneville.

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AuotonomousRX
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Re: Vespa Dry Lake Racer lives...

Post by AuotonomousRX »

That is what I thought JP but the Snowmobile, Grass Sled and Sand Racing mob have been forcing air into to Smokers for a while now, it can be done.

No doubt as with most things getting it to work involves a lot of development time and parts.

Both of these Blown Builds are looking fantastic.

Pete :D
Still trying to decide if I am a procrastinator

Pete :?
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