HPV Fairing Construction

[MetroMPG]

When we get results from scale tunnel testing - I'll let you know what our Cd is

Cool!

And can you fit the Jetta in the tunnel afterwards?

Even with the tadpole design, wouldn't the faired, but exposed front wheels permit a lower frontal area? A la Aptera hybrid design?

(Obviously I can't comment on how it would affect Cd though...)

[trebuchet03]

Originally Posted by MetroMPG

Cool!

And can you fit the Jetta in the tunnel afterwards?

Even with the tadpole design, wouldn't the faired, but exposed front wheels permit a lower frontal area? A la Aptera hybrid design?

(Obviously I can't comment on how it would affect Cd though...)

I wish I could fit the car in there :P We fit a 1/12 scale model of the fairing in the tunnel - the tunnel is capable of around 100mph wind speed. So scaled, that's ~8mph :P Not too fantastic, but we can extrapolate data from it.

I don't think it's going to happen - but the idea of putting it into a water tunnel for flow visualization was thrown around for awhile... Which reminds me -- I have some pictures from when we were allowed to fill the water tunnel. Want to compare apples to oranges? Literally? I'll have to dig those up and post

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As for frontal area.... No, because of width - remember, you still need to be able to peddle in there For non HPV, I think the tadpole design is better (based on the vehicles that win fuel economy records). The Varna HPV design has proven to be the most aerodynamic at the moment - that design currently holds the iHPVA speed record of 81mph (DiabloII).

[trebuchet03]

Instructables (includes another time lapse video):

http://www.instructables.com/id/EFPZ1HN4FWEZ439XF9/

Tomorrow we Vacuum Bag

[MetroMPG]

FYI - there's a piece up at ABG today that shows the foam shaping process for making a fiberglass kit car body. The car is being touted as a 3-wheel diesel plug-in hybrid:

http://www.autobloggreen.com/2007/04...r3-hybrid-fro/

[MetroMPG]

Did you ride the '06 HPV? I'm curious what it was like.

[trebuchet03]

Originally Posted by MetroMPG

FYI - there's a piece up at ABG today that shows the foam shaping process for making a fiberglass kit car body. The car is being touted as a 3-wheel diesel plug-in hybrid:

http://www.autobloggreen.com/2007/04...r3-hybrid-fro/

Very cool - reminds me of the T-rex recumbent motortrike Their manufacturing process is pretty similar - except they are making a part off of their foam before making their tool. That works well when you want to make a prototype before going into mass production (saves quite a bit of money ). I also like how they are shaping their plug -- that's a much easier way to get organic lines

Did you ride the '06 HPV? I'm curious what it was like.

You bet I did We had a flaw in our steering though -- a castor angle of 15 degrees -- which made the steering "floppy." The result was a VERY steep learning curve (with a lot of fall over type crashes). But once you got it - you got it. Kinda like re-learning how to ride a bike, only harder. Because of this defect, the vehicle is retired.

The fairing was really cool. All of the comments said "SpaceshipOne" due to our window layout. Why? Well, those circular windows allow very good visibility without needing to manufacture a window with difficult compound curves. Honestly, the window design started off as a joke :P We also painted the inside of the fairing top black to help with visibility. That fairing also surved some rather nasty crashes (especially one 30'+ slide on oval track pavement). It was designed using either S or E glass with K-mat (a fiberglass backed scored foam core).

[MetroMPG]

I don't know what you'd compare it to, but could you discern any reduction in pedal effort to ride the thing because of the fairing?

[trebuchet03]

Originally Posted by MetroMPG

I don't know what you'd compare it to, but could you discern any reduction in pedal effort to ride the thing because of the fairing?

Very much so. Especially when you get above the 15-20mph range.

That fairing has a removable bottom section to allow your feet to come down.

(Sorry for size) Note battle scars on fairing.

In the 100m trap, we shaved off about a second when the fairing had that bottom piece mounted (making it fully "sealed"). That could be due to fluxations in the human engine :P But because they wouldn't time us without some sort of fairing (as per ASME rules), I can't give you anything better for comparison. Oh yeah, the average speed was 35mph through the trap

Try riding a bike faster than 20mph... Even with no wind, you can feel a significant amount of resistance. Our CFD model showed about 5lbs of wind resistance at 30mph (I think it was 30). Our tunnel testing confirmed that the model was pretty damn close. Oh, and the models didn't include the rear wheel fairing bit (couldn't get it to mesh).

Sorry for these longwinded posts :P I just don't want to leave out some of these details :P

[trebuchet03]

Just a sneak peak

[zpiloto]

Originally Posted by trebuchet03

Very much so. Especially when you get above the 15-20mph range.

That fairing has a removable bottom section to allow your feet to come down.

(Sorry for size) Note battle scars on fairing.

In the 100m trap, we shaved off about a second when the fairing had that bottom piece mounted (making it fully "sealed"). That could be due to fluxations in the human engine :P But because they wouldn't time us without some sort of fairing (as per ASME rules), I can't give you anything better for comparison. Oh yeah, the average speed was 35mph through the trap

Try riding a bike faster than 20mph... Even with no wind, you can feel a significant amount of resistance. Our CFD model showed about 5lbs of wind resistance at 30mph (I think it was 30). Our tunnel testing confirmed that the model was pretty damn close. Oh, and the models didn't include the rear wheel fairing bit (couldn't get it to mesh).

Sorry for these longwinded posts :P I just don't want to leave out some of these details :P

To cool. Couple of questions. Sorry to rapid fire them at ya:
How heavy is the shell and total weight of HPV?

What's the size (teeth) of the big change ring? Is it set up with a single speed hub? If so what the gear ratio?

I guess you have 300m to speed before the trap. Do you know what kind of wattage is required to reach that speed?

Does it heat up pretty quickly inside when your working hard?

And last for now. Has anyone tried the superman postion instead of the recumbent for the HPV? I would thing that you might be able to develope more power that way or does it require a bigger shell?

Sorry for the 20 questions but this really is cool.