Vespa Dry Lake Racer lives...

See cars and bikes being built for the salt

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momec3
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Re: Vespa Dry Lake Racer lives...

Post by momec3 » Thu Mar 20, 2014 10:08 pm

Enzo Ferrari said "Aerodynamics is for those who can't build horsepower" :lol:
Chris

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dplecko
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Re: Vespa Dry Lake Racer lives...

Post by dplecko » Fri Mar 21, 2014 12:37 am

With respect to everybody; this frontal area is quite differant to other pics posted by green hornet...(we all kwnow the the v formula)

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internetscooter
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Fri Mar 21, 2014 8:13 am

Yes - I need to hit the dyno - from last measurement if I put my engine in JP's bike it should have done 100mph ;)

dplecko I'll also be blowing the dust off my homemade data logging kit (shelved after a long long exercise in discovering how to accurately measure wheel rotation speed). You have a pretty good set-up - all you need to do to work out the forces you are fighting is to pull the clutch in :) The only thing that will change your velocity is the air and rolling resistance and therefore your measuring deceleration and mass will enable it to be measure the forces.

Ferraris are for those who can't build horsepower ;)
Paul
---
DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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Lynchy
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Re: Vespa Dry Lake Racer lives...

Post by Lynchy » Fri Mar 21, 2014 9:03 am

One of my team came back in the office yesterday grinning and then told us about how he was walking back to the office via the Ferrari/Lamborghini dealership in Fortitude Valley. Some clown out front was revving up his Faz ready to make a scenic departure and pulled off with intent - only to run into a bus.... :oops:

Bus 1 - Ferrari 0

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RGV
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Re: Vespa Dry Lake Racer lives...

Post by RGV » Fri Mar 21, 2014 9:41 am

Lynchy wrote:One of my team came back in the office yesterday grinning and then told us about how he was walking back to the office via the Ferrari/Lamborghini dealership in Fortitude Valley. Some clown out front was revving up his Faz ready to make a scenic departure and pulled off with intent - only to run into a bus.... :oops:

Bus 1 - Ferrari 0

Where's the LIKE button?

Dave

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2010 MPS/G 250 118 MPH:)
2011 Washed Out:(
2012 Washed Out:(
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dplecko
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Re: Vespa Dry Lake Racer lives...

Post by dplecko » Fri Mar 21, 2014 10:56 am

I cobbled together some electronics for an intertial dyno over 20 years ago (quite an achievment at the time - took minutes to compute then draw the graph), it is trully amazing how accurate they can be.

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RGV
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Re: Vespa Dry Lake Racer lives...

Post by RGV » Fri Mar 21, 2014 11:11 am

I was talking to a guy at the canteen one night about dyno's. He had built one using a load cell like this. Easy conversion from ft/lbs to HP.

http://www.ebay.com.au/itm/221386078007 ... 1423.l2649

Last Minute Racing "its a 2-stroke ya twit - Its supposed to smoke"
DLRA #928
SATA #10

2010 MPS/G 250 118 MPH:)
2011 Washed Out:(
2012 Washed Out:(
2013 MPS/G 250 131 MPH (RECORD):)
2014 MPS/G 250 140 MPH (RECORD):)
2015 MPS/F 250 DNF:(

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internetscooter
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Fri Mar 21, 2014 12:25 pm

RGV wrote:I was talking to a guy at the canteen one night about dyno's. He had built one using a load cell like this. Easy conversion from ft/lbs to HP.

http://www.ebay.com.au/itm/221386078007 ... 1423.l2649
Very nice! - just added to my list of sensors to include - I can read any value so I will go for a more sensitive one without the display. Thanks!

I did spend a lunch break looking at torque sensors, that would be very very nice to read the Hp straight from the wheel strain!

A quick google gives one overview:
http://www.testing-expo.com/europe/12tx ... _Novak.pdf
Paul
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Vespa Labs [url]http://www.vespalabs.org[/url]

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dplecko
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Re: Vespa Dry Lake Racer lives...

Post by dplecko » Fri Mar 21, 2014 1:22 pm

AEM have an interesting load cell in the tailshaft:
http://www.google.com.au/search?q=AEM+t ... s&tbm=isch

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internetscooter
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Sun Mar 23, 2014 7:18 pm

Actually I just found that I noted down my googling result and found a motorcycle version :) http://www.vespalabs.org/Projects/Scoot ... que_Sensor but that is about as far as I got. Don't know where you get them or how much: http://www.gtme.co.uk/Torque.aspx?id=14 but it wouldn't fit on my Vespa anyway :( Someone else can try :)

I am concentrating on a hall effect sensor for accurate wheel rotation measurement - should be able to achieve the same result :) Will try an get it working this week so I can compare it to the dyno result (booked in for Sat).
Paul
---
DLRA #647
89.664 mph (aiming for 100mph+)
Vespa Labs [url]http://www.vespalabs.org[/url]

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internetscooter
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Sat Mar 29, 2014 1:01 pm

Good news?! The dyno run today shows me quite a few horses have bolted and I only have 22Hp (down from 32Hp) - this explains a lot!

1-2Hp is due to the side panel alone! This is probably even more at higher speeds due to even more restricted air flow - though I tried measuring a pressure drop on my road scoot and couldn't see anything of note.

I suspect the other Hp's may be due to seals not handling the intermittent starting (i.e. many months sitting still and then being thrashed - I did note oil after the first few starts but then it stopped).

Next step rebuild the engine without changing anything and see if I can get back to 32Hp (there were a few splutters which might indicate electrical problems also).

I'll process the dyno graphs for more detailed info.

Lesson learnt - if my mates dyno is not functioning before the salt, pay for a dyno beforehand and get 100mph+ rather than pay for one after to work out what went wrong!

edit: adding dyno result...

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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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gennyshovel
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Re: Vespa Dry Lake Racer lives...

Post by gennyshovel » Sat Mar 29, 2014 4:41 pm

You might need this Paul

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Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

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Greg Watters
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Re: Vespa Dry Lake Racer lives...

Post by Greg Watters » Sat Mar 29, 2014 7:01 pm

How does the lower hp look with your achieved speeds , does it correct the calculations ?

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internetscooter
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Sat Mar 29, 2014 9:07 pm

Greg Watters wrote:How does the lower hp look with your achieved speeds , does it correct the calculations ?
I'll need to do some more scribbling on the chalk board - I suspect the RPM on the chart is wrong as it is based on my rev counter and I don't trust it to be correct. The rear wheel speedometer reading showed max speed of just under 100mph, which suggests that I am not only fighting with lost power but short RPM range.

My mates dyno should be online in another few weeks so I can do further testing and compare. I have dyno'd the scoot on this other dyno before so I am comparing apples with apples (just the rpm has always be suss due to the way he runs the dyno).

I'll keep the thread updated.

Tiny I'll try the power band out in your private race track ;)
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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internetscooter
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Re: Vespa Dry Lake Racer lives...

Post by internetscooter » Mon Mar 31, 2014 12:43 pm

OK more info...

Added the "Bad" Hp results (mapped against the 4 gears) and left the old good results (dotted lines) and then tweaked the Hp to overcome drag (red line) to emulate what happened at the lake. To fit the Hp to overcome drag I just added more frontal area (as I was not sitting as low) and guesstimated the rest in Cd till 4th maxed out at 90mph (red became more than green). The Cd should be lower but rolling resistance would account for some of the extra I had to add.

So I have to get the red line down and regain my power. I will redo the dyno on my mates one (where the good results were taken) so I have an additional data reference to go by. I'll also redo the CFD simulations with me sitting in a more upright position.

http://files.internetscooter.com/dlra/2 ... alysis.jpg (click here is the image is too big for your forum view)

Image
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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