Vespa Dry Lake Racer lives...

See cars and bikes being built for the salt

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internetscooter
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Tue Dec 31, 2013 6:24 pm

The blower is a centrifugal one so it gets more efficient at higher RPM. This should in theory make the power curve more like the power to overcome drag curve, so I get power where it's missing (i.e. it keeps heading north after 95 mph). It was also to change my class as chasing 130+ is kinda hard (especially with no tyres rated that high), chasing zero is a bit more doable ;)
Paul
---
DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Wed Feb 26, 2014 8:25 pm

Still packing... heading off Saturday morning...
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Paul
---
DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Sat Mar 08, 2014 9:47 pm

Ok it's been a long drive back - I will do a full write-up and add a link - the short version is that I did 89.664 mph after lots of challenges. That time was a flying mile!!! Due to lake issues the track was moved and instead of measuring the time over 1/4 mile I had to do full throttle for a full 1 mile, through what felt like a beach which had loads of 4wd tracks through it - my arms are still aching.

The main issue was that I could not sit in the low down position I did all my calculations on as it was WAY too unstable :( When my weight went past the rear axle it felt like I was riding backwards. If I had taken the screen and the track was good and had only 1/4 mile timing I might have got 95mph (so still more work required for 100mph+)... Also I need to factor in the parasitic loss of the salt...

Thanks Tiny, Bob, Graham and Ross for the support!

It was a great week and thanks to all the organisers you have done a brilliant job!

Image

Image
Paul
---
DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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Re: Vespa Dry Lake Racer lives...

Post by momec3 » Mon Mar 10, 2014 8:39 pm

Well done Paul,
The salt is a harsh Mistress :?

Chris
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Thu Mar 13, 2014 10:12 am

Yes indeed - I still am scratching my head and need to dyno the scoot to see what is up. I went through my old dyno results and mapped it against gearing and even adding a 20% increase in frontal area (because I could not sit as low) and 20% increase in Cd I still should have seen 100mph. The way the scoot behaved (struggling to change from 3rd to 4th and keep accelerating) suggested I had half the power I thought I had. Or maybe if my chest is at a certain height, I became like a parachute directing air into the void rather than over the top?

For those that did 100mph+ what was the Hp you needed?

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Paul
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DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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Re: Vespa Dry Lake Racer lives...

Post by dplecko » Fri Mar 14, 2014 12:19 am

Hi Paul,

To answer your question, and i might sound stupid for saying this after 300 dyno runs: 'I think' I had about 35HP, but it's a very very flat curve. Still still trying to calibrate the model (which is a bit rough at best). Guessing 0.85-0.95 drag & 0.46 frontal. Was hoping to catch up with you on the salt.

1st & 2nd are short shifted

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Re: Vespa Dry Lake Racer lives...

Post by AuotonomousRX » Fri Mar 14, 2014 8:55 am

Hi Paul

It was good to finally meet you, big effort setting a PB, congratulations.

When I ran the stock RGV in 2010 in M-G-250 I discovered the importance of Aero and Frontal Area.

If I lifted my Head just the slightest little bit, my Speed dropped and I could not go over 180kph. I eventually went 119mph on the GPS track twice, so that was maxed out with about 60 Dynojet rwhp.

So I would say getting yourself as low as possible is your Big challenge.

Pete :D
Metric Target 250 on a 250 on a Red Bike

Pete :shock:
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Fri Mar 14, 2014 12:58 pm

Yes - low as possible is on my list but there are a few other things I am pursuing as the possible contributors...

I estimate that 30 Hp should be enough for 100mph and after that a rapid increase in Hp is required to make small improvements (as we all know). dplecko your results support this theory, thanks for sharing them!

One thing I am looking at is the possibility that I have generating negative pressure under my sidepanel where the carb sits. So as I get faster my power will drop.

I did a quick map of negative pressure in my simulation and indeed I see a negative pressure region developing where the carb inlet is. I have a pressure sensor which I dusted off last night and I will try an measure some real values to see what they tell me. Below is a image showing a "skin" around a negative pressure value, everything inside the "skin" is more negative than everything outside.

Image

edit: Or it could be the cowl restricting the air outright - I don't think I have dyno'd it with the cowl on!!!
Paul
---
DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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Re: Vespa Dry Lake Racer lives...

Post by Stayt`ie » Fri Mar 14, 2014 2:02 pm

Paul, dose the "closeness" of the web indicate negative pressure regions, ??,,
First Australian to ride a motorcycle over 200mph at Bonneville,,,

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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Fri Mar 14, 2014 2:36 pm

Stayt`ie wrote:Paul, dose the "closeness" of the web indicate negative pressure regions, ??,,
No that is just resolution of the mesh it was calculated with - think of it as a balloon in "opposite world" - if you could blow up a balloon with negative pressure that is the shape it would make. Hope that helps explain ;)
Paul
---
DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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Re: Vespa Dry Lake Racer lives...

Post by Stayt`ie » Fri Mar 14, 2014 4:25 pm

yep,yep, thanks,, 8) ,
First Australian to ride a motorcycle over 200mph at Bonneville,,,

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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Thu Mar 20, 2014 9:47 am

More evidence that 32Hp should be enough - Tony O'Brien just got 116.2 mph in the UK! He has approx 32Hp but a lower frontal area.

http://79.170.44.125/green-hornet.co.uk/?p=1030

Image

I need to get to a dyno...
Paul
---
DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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Re: Vespa Dry Lake Racer lives...

Post by RGV » Thu Mar 20, 2014 10:09 am

Nice result but the big white dyno seems to suck top speed. No way my bike will get to redline in the top 2 gears on the lake. No over rev. It hits max HP and stops. Get this guy out to the lake. ;)

Dave

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Re: Vespa Dry Lake Racer lives...

Post by jpbyron » Thu Mar 20, 2014 1:47 pm

Here are some numbers from our bike at Speed Week,

21 rear wheel HP - 94.8mph - with fairing, but head and shoulders still way above. Also bike 170 pounds rider 187 pounds.
Without Fairing 93.5mph bike same weight but rider 154 pounds.

I think you will need 30 plus some, its a big wall you are pushing, and for me 94.8 to 100mph is going to take a few more HP. Remember that guy who ran on the scooter in post above was top speed, its another game to hold it flat out for a mile and another mile run in. We also had wheel spin even at low HP, it like the salt just moves, so another 5% loss there.

Why bugger around, boost her up for kill and grab 40hp and blow through that 100mph .

Great meeting you at Speed Week.

JP
APS-BF 100 109.589mph
Worlds fastest 100cc motorcycle

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Re: Vespa Dry Lake Racer lives...

Post by dplecko » Thu Mar 20, 2014 9:23 pm

Agreed with JP. Unless you want to chop your bike half, HP is gold. Just make sure that it makes more HP the longer it runs (one minute @ 100%) not the other way around...

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