Author Topic: Electrathon Aerodynamics  (Read 5255 times)

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Offline 4stroke

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Electrathon Aerodynamics
« on: January 13, 2016, 06:52:51 PM »
Hello.

In a recent thread of mine I determined that the stability of a three wheeled streamliner will allow for better practical streamlining for on road driving.

I have since discovered electrathon in which competitors try to get the highest average speed to achieve the most laps of a course in 1 hour (lately they have been reaching 60-63mph).  This is on about 1kwh of lead acid batteries.  Some of them also entered into an electrathon category at Bonneville  Interesting stuff.

Here is a story about the Electrathon category for speed racing.
http://brucesherrydesigns.com/blog/category/electrathon/

What I'd like to learn from this thread is:

1) Aerodynamics flat bottom vs round for low drag (10cm minimum clearance for on road and lower for land racing/electrathon) (see attached picture).

2) Two wheel or one wheel up front?

3) External wheels or internal (inside the main body fairing or with their own wheel cover).

4) Are there any low rolling resistance speed rated motorcycle wheels/tires?  I am considering ct90-ct110 wheels as cheap and light weight wheels (no idea what their rolling resistance is).

5) Minimizing vehicle weight without expensive monocoque body.  Can this be done effectively?

As for what this vehicle will be used for, it will be for a commuter vehicle and it would also be interested to see how it goes in efficiency "races" and to find out what the top speed can be achieved.

Thanks.
« Last Edit: January 13, 2016, 07:04:39 PM by 4stroke »

Offline Rex Schimmer

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Re: Electrathon Aerodynamics
« Reply #1 on: January 13, 2016, 07:24:42 PM »
I think that the British Robin has proven that if you are going to drive it on the street and it only has 3 wheels the best set up is to have two in the front and the single in the rear.

Rex
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Offline manta22

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Re: Electrathon Aerodynamics
« Reply #2 on: January 13, 2016, 08:16:29 PM »
Three-wheeled vehicles have poor handling on the road. The end with one wheel has zero roll resistance. Even ATVs abandoned that configuration years ago.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline Peter Jack

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Re: Electrathon Aerodynamics
« Reply #3 on: January 13, 2016, 08:40:45 PM »
Tadpole configuration seems to work much better than tricycle. The Morgan three wheeler is a great example.

Pete

Offline 4stroke

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Re: Electrathon Aerodynamics
« Reply #4 on: January 13, 2016, 08:51:14 PM »
I think that the British Robin has proven that if you are going to drive it on the street and it only has 3 wheels the best set up is to have two in the front and the single in the rear.

Rex

I was also concerned about the roll over stability of delta trike configuration (1 wheel up front 2 in the rear).  Drift trikes are a good example of proper center of mass placement.

https://www.youtube.com/watch?time_continue=169&v=NvUAuNt1wNY

One complication that can occur with the delta trike is you cannot easily see if you have enough clearance for the back wheels.  Just like a cat's whiskers or a motorcycle's handle bars a reverse trike driver can easily gauge if they have enough clearance to move between tight spaces (filtering traffic).

For this reason and the reason I'd prefer tadpole configuration.
« Last Edit: January 13, 2016, 08:52:52 PM by 4stroke »

Offline 4stroke

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Re: Electrathon Aerodynamics
« Reply #5 on: January 13, 2016, 08:57:31 PM »
I think that the British Robin has proven that if you are going to drive it on the street and it only has 3 wheels the best set up is to have two in the front and the single in the rear.

Rex

I was also concerned about the roll over stability of delta trike configuration (1 wheel up front 2 in the rear).  Drift trikes are a good example of proper center of mass placement.

https://www.youtube.com/watch?time_continue=169&v=NvUAuNt1wNY

One complication that can occur with the delta trike is you cannot easily see if you have enough clearance for the back wheels.  Just like a cat's whiskers or a motorcycle's handle bars a reverse trike driver can easily gauge if they have enough clearance to move between tight spaces (filtering traffic).

For this reason and the reason I'd prefer tadpole configuration.

Can't use four wheels because that counts as a car, also they are less efficient.

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Re: Electrathon Aerodynamics
« Reply #6 on: February 11, 2016, 03:19:58 AM »
I think that the British Robin has proven that if you are going to drive it on the street and it only has 3 wheels the best set up is to have two in the front and the single in the rear.

Rex

I was also concerned about the roll over stability of delta trike configuration (1 wheel up front 2 in the rear).  Drift trikes are a good example of proper center of mass placement.

https://www.youtube.com/watch?time_continue=169&v=NvUAuNt1wNY

One complication that can occur with the delta trike is you cannot easily see if you have enough clearance for the back wheels.  Just like a cat's whiskers or a motorcycle's handle bars a reverse trike driver can easily gauge if they have enough clearance to move between tight spaces (filtering traffic).

For this reason and the reason I'd prefer tadpole configuration.

Can't use four wheels because that counts as a car, also they are less efficient.
For this configuration, two wheels side-by-side or in tandem up front makes it a legal "car".

Offline 4stroke

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Re: Electrathon Aerodynamics
« Reply #7 on: February 13, 2016, 08:22:56 PM »
I think that the British Robin has proven that if you are going to drive it on the street and it only has 3 wheels the best set up is to have two in the front and the single in the rear.

Rex

I was also concerned about the roll over stability of delta trike configuration (1 wheel up front 2 in the rear).  Drift trikes are a good example of proper center of mass placement.

https://www.youtube.com/watch?time_continue=169&v=NvUAuNt1wNY

One complication that can occur with the delta trike is you cannot easily see if you have enough clearance for the back wheels.  Just like a cat's whiskers or a motorcycle's handle bars a reverse trike driver can easily gauge if they have enough clearance to move between tight spaces (filtering traffic).

For this reason and the reason I'd prefer tadpole configuration.

Can't use four wheels because that counts as a car, also they are less efficient.
For this configuration, two wheels side-by-side or in tandem up front makes it a legal "car".

If it has more than 3 total wheels it is counted as a car according to Australian law.
3 wheeled vehicles are required to have two of those wheels symmetrical side by side.
In electrathon there is a minimum track width of 2", a good rule to prevent roll over.

I am now designing an efficient ebike for a competition in August which should give me some great experience with the fabrication and electronics needed for future projects such as the one in this thread.

Offline Polyhead

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Re: Electrathon Aerodynamics
« Reply #8 on: February 13, 2016, 09:04:08 PM »
Well, I'm not sure what your personal experiences are, but I took a Catrike (http://www.catrike.com/) down Mt. Tabor here in portland.  (https://en.wikipedia.org/wiki/Mount_Tabor,_Portland,_Oregon).  They are FAIRLY stable, although, you can certainly tip it over.  That said I pushed the bike to 45mph and wasn't too overly concerned.  I still want to try one down cornell road.  I've had normal bikes reach 55mph on that stretch and did fairly well right up to the end where I attempted to carry too much speed into a turn and reached the limits of traction around 25mph.  That was a good bit of road rash that one.  I had the tires down to 700x23 in size to minimize wind resistence and I should have stuck with 700x28's.

 FYI, my best speed on a gravity bike thus far is 68mph comming down the roads off of mt. hood.  Rim brakes be bad joo joo.  They keep working... but the rim gets hot under heavy breaking and softens the tube, and then the tire starts going flat.  
Ben 'Polyhead' Smith
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Offline dw230

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Re: Electrathon Aerodynamics
« Reply #9 on: February 13, 2016, 09:34:30 PM »
"If it has more than 3 total wheels it is counted as a car according to Australian law."

Well good for them. What do the rule books of FIA, DRLA and SCTA say about wheel number and configuration. We are here for records, not dreams.

DW
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