Vespa Dry Lake Racer lives...

[ChrisACT]

Can't see any blowers but there does seem to be a lot of top end transplants in this lot.


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.... and don't they just sound wonderful? TURN IT UP!!

[internetscooter]

"A" turbo has been done before and yes a lot of top-end conversions - mine will be the first with both


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On the build diary front I had a set back - crunched my CNC machine making the first prototype mounting bracket. Should be easy to fix (new gear in the head I suspect), so more annoying than anything else as it is diverting my effort. On the good news front the interest rate drop pushed up the dollar and I am closer to buying the supercharger

[harky]

so ---the 14minutes of a million bees noise --- where is that ( france?) and what distance are they running ? some seem to have some serious power !! the technique for take off is interesting ------- could be painfull to the boys bits !!!
still ---- yep loved it ------even the dying bees noise
harky

[AuotonomousRX]

So that would be Top Vespa and Pro Stock Vespa!!!

Fantastic I wonder what Mr Piaggio would make of that

Pete

[internetscooter]

Fantastic I wonder what Mr Piaggio would make of that

Pete

Mr Piaggio hates it - they love people who buy new shiny Vespa's yearly and distance themselves from scooterists that keep old scoots going for years (and going faster)

[AuotonomousRX]

LOL

[RGV]

Where is it?? Im selling up and moving. What a great noise. I want to live in the house on the start line.

Here in Aust. we shut the roads for Lycra clad people to ride on our roads. There they shut roads for Leather clad people to ride their motor bikes as fast as they can go in what 200 meters?

Dave

[internetscooter]

Where is it?? Im selling up and moving. What a great noise. I want to live in the house on the start line.

Dave

Dave just move anywhere in Italy


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[AuotonomousRX]

...viva l'Italia!

[internetscooter]

...viva l'Italia!

My wife and I toured Europe on Vespa's for our honeymoon. When we entered Italy, scooters just did whatever they wanted - at one stage we were in a bunch of about 30 filtering up through traffic with oncoming cars having to give way. We said to each other "What do the cops think of this!?". Just then 2 motorcycle cops pulled out of a side street... we thought they were going to pull everyone over... No... one just pulled a wheelie half way down the street showing off and they disappeared (probably to the pub

[David Leikvold]

They're all racers at heart. Back in the 80's when I was a Contiki driver in Europe I spent a lot of time in Italy. The city traffic was amazing. At any set of lights it didn't matter how far back from the lights you were, you stepped off the clutch when the lights went green, the cars in front of you were already moving as one, albeit not much faster than the bus as most of them were Fiat 500 Bambinos! It was also a very crowded part of the world, the road back to Seven Hills Camping near Rome was narrow and twisty and people would often park with scant regard for other motorists. This was often a problem for our bus so I'd get 8 or so of the guys onboard to hop off and bounce little cars out of the way. One night we were moving a Citroen 2CV out of the way and one of the mudguards was ripped clean off by the enthusiastic bouncing. Serves him right for buying such an automotive abomination!

Another day I was somewhere in Italy when I was stopped by the cops so they could read my tachograph card to check if I had been speeding that day. The speed limit was 100km/h but the bus company only allowed us to do 90km/h, which was all I was doing. The cops were flabbergasted and hugely disappointed that any man would drive under the speed limit!

[internetscooter]

Ok a lot of stuff going in the background - so an update is due I think…

Firstly on Computation Fluid Dynamics (CFD) modelling:

The book "Aerodynamics of Road Vehicles (4th Edition) - Hucho, Wolf-Heinrich" has helped me understand a lot. The state of the art (even now) is that CFD can predict drag coefficient (Cd) to about +/-5%, however we need a resolution of <0.5% to do useful measurements (i.e. make small changes and say they improve overall Cd) - so CFD is more about predicting/analysing where problems might be so that further tests can be carried out (i.e. wind tunnel or real life riding).

I was getting carried away with trying to model the scooter as it is now and then measure the incremental changes. Now I can just jump in and start changing stuff, then look for problem areas without worrying too much about Cd (though it will help in the overall prediction for gearing and power requirements). This also means I can avoid wasting time filling holes in meshes I am going to cover up anyway, to make them suitable for CFD and I can make new aerodynamic parts which will by default come hole free (as they weren't produced by a 3D scanner).

So I have finished my first cut of a CFD pipeline and the first test with a subset of model bits shows that removing the front indicators made a huge improvement. With indicators I had huge negative pressure regions either side of the scooter near the glovebox. Removing them has removed these regions entirely and the run now shows the next problem area is the lip around the leg shields (the pink colour which contours similar pressure values). This lip can easily cut off but I will throw the rest of the model together before I do anything physical



Then on the Physical side - I have sorted out a lot of problems with the CNC machine - experimental cuts showed I had "issues". After a long learning exercise it is now centred correctly, backlash correctly compensated for, correct clamps purchased, tolerances in mill bits known and everything shielded to prevent electrical noise… now I can cut a circle and it looks like a circle

Hopefully the next post will either be something concrete produced from the process (i.e. aerodynamics parts) or a picture of the new addition to the project that I am expecting in a few weeks

[DLRA]

Amazing Paul, just amazing!

[RGV]

Looking good Paul.

Dave

[internetscooter]

Thanks - Greg (and others reading with a computer background) - I should point out that I am using open source software for this and making all the stuff I produce also open source https://github.com/internetscooter/Vespa-Labs

The hardest part is getting the model to run the simulations on, if anyone has this, then the next hardest part is setting up all the software. If anyone has a model and is interested in trying this out then I am happy to put together a VM with everything pre-configured. I am running on a super computer but the only unique bit I am using (at the moment) which is hard to come by is RAM. I have 192G available, which means I can do higher resolution simulations, however lower res simulations will still tell you something and it is easy (now I know) to tweak a few parameters to make it use less memory.