Rear fenders only

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SPEEDQUEST
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Rear fenders only

Post by SPEEDQUEST » Sun Jan 04, 2015 1:33 pm

I noticed a lot of pics of cars posted on this site of cars with extended wheelbases and rear fenders only.. Are the rear only fenders found to be beneficial? I am helping my nephew build a car for his pack race. I have been out of building for a few years, since finishing runner-up to Warpspeed in Council.



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sporty
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Re: Rear fenders only

Post by sporty » Sun Jan 04, 2015 1:57 pm

Welcome back. Been awhile for you.

I think rear fenders are easier to do then the fronts. But the rears I hear are mostly done to have the air go wider and create some turbulence for the car in the next lane.
When I used a wind tunnel for testing. A professional model.
I just didn't find that there was air that far back to matter. But they look neat.
full fender cars only ever seem to show a tiny. Tiny amount of gain. It's easier to go backwards in eta. Times. Then forward.
but many use fenders because it seems to slow the car next to them. If they don't have fenders.
mostly balsa is used. Or very light material.

More so. It's the cant. Railriding. Oil/ wax that's what everyone is doing.
The grooved axled. And 92 and 93 size axles with oil. And sometimes with graphite the 91.size. even seen 92. With graphite. Sized axles.

The super thin and light cars. 5 gram bodies.
allot doing the super light. Thin bodies these days.
monokote covering.



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Vitamin K
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Re: Rear fenders only

Post by Vitamin K » Sun Jan 04, 2015 2:25 pm

sporty wrote:Welcome back. Been awhile for you.

I think rear fenders are easier to do then the fronts. But the rears I hear are mostly done to have the air go wider and create some turbulence for the car in the next lane.
Huhn, that's interesting.

My son's car, incidentally, was planned to have front and rear fenders, but he decided he didn't want the front, so it'll just have rears. No idea what that'll do performance-wise.

I would like to see some tests, though, regarding "traffic" turbulence and fenders. Both "offensively" and "defensively" speaking.



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whodathunkit
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Re: Rear fenders only

Post by whodathunkit » Sun Jan 04, 2015 6:07 pm

sporty wrote: When I used a wind tunnel for testing. A professional model.
I've seen the photos of it on DT. ;)


(If someone is looking for wind tunnels for testing PWD cars with)
The Applied Educational Systems. inc aerostream model 21 wind tunnels.

Can be found from time to time as well.
http://www.publicsurplus.com/sms/docvie ... id=6527159

However .. Hold on to your pocket book!!!
And be ready to pay the price for one.. I've been watching a few of these
aes aerostream model 21 wind tunnels sale for around $750.00 or more here lately.


What type of automobile can be spelled the same forwards & backwards?

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davet
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Re: Rear fenders only

Post by davet » Mon Jan 05, 2015 1:06 pm

For our Pack race last year we came in a very close 2nd to a full fendered, standard wheelbase car. We were extended with no fenders. For the District race we added rear fenders and had consistently faster times than the car that beat us at the Pack. Not sure if he did something that made him slow down but we also reprepped our wheel and axles.



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