2010 Test cars

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Grubartez
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Re: 2010 Test cars

Post by Grubartez »

FatSebastian wrote:
pwrd by tungsten wrote:The track record at PDDR for standard BSA wheel base and unlightned wheels was just set by a car with rear fenders. :D
Is this the car?
...
There are very many interesting aspects to this design, especially the rear wheels with the sidewalls facing inward (presumably to deal with new double-step recess on the outer hub?). The windshield behind the (presumably non-dominant) black tire is also interesting.

The nice thing about the tire windshield and fenders in this design is that they allow for a certain level of streamlining around the wheels without increasing the cross-sectional area of the body in the direction of motion (which seems to have been minimized already).
pwrd by tungsten wrote:I think fenders will change the sport for league racing next year and BSA racing soon as well...
:thinking: Sporty, can you attach some rear fenders like this on one of your thin test bodies and report back on how many milliseconds are gained?

The wheels running on this car are not the new style BSA wheels. They are the 3.3 g Jewkes old style wheel. The outer hub has been turned down/reduced in length to allow for them to be ran this way. I should have a car ready to test this way by the weekend. The fenders are shaped, primed and ready to paint. I'm very curious how it's going to do.
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pwrd by tungsten
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Re: 2010 Test cars

Post by pwrd by tungsten »

That is the car. [no advertising for this vendor] did a nice job on the car. Thes are the old wheels. I will post more details tonight.
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FatSebastian
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Re: 2010 Test cars

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Grubartez wrote:The wheels running on this car are not the new style BSA wheels. They are the 3.3 g Jewkes old style wheel. The outer hub has been turned down/reduced in length to allow for them to be ran this way.
Thanks much for the clarification. So then, what is the supposed advantage of turning the sidewalls inward? :scratching:
Grubartez wrote: I should have a car ready to test this way by the weekend. The fenders are shaped, primed and ready to paint. I'm very curious how it's going to do.
Can you do some "before and after" runs with and without fenders and report back some numbers? :eager:
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Pinewood Daddy
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Re: 2010 Test cars

Post by Pinewood Daddy »

I like the idea of running the wheels with the inner hub out. That would eliminate having to modify the countersink on the outer side of the bore (against our rules). Does the open profile cause any extra turbulence?? I still need confirmation the new wheels will be allowed in our District.

I also like the idea of the fenders on the rear tires but I'd be afraid of them accidentally touching the rail due to some possible rear end wiggle going over rough track joints.
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Re: 2010 Test cars

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FatSebastian wrote:
Grubartez wrote:The wheels running on this car are not the new style BSA wheels. They are the 3.3 g Jewkes old style wheel. The outer hub has been turned down/reduced in length to allow for them to be ran this way.
Thanks much for the clarification. So then, what is the supposed advantage of turning the sidewalls inward? :scratching:
Grubartez wrote: I should have a car ready to test this way by the weekend. The fenders are shaped, primed and ready to paint. I'm very curious how it's going to do.
Can you do some "before and after" runs with and without fenders and report back some numbers? :eager:
What I can tell you is I sent out a car with basically the same design and shape and wheels. The front raised wheel had the wind deflector and it also had the rear fenders with the rear wheels running in the normal position. Now, on my 42' ft Best track it ran a 2.948 avg with a 2.942 fast pass. During shipment, the right rear fender was damaged and had to be repaired the best it could at the event. The car ran a 2.963 avg with a 2.959 fast pass. When the car arrived home, I ran it again to see and again it ran a 2.963 avg with a 2.960 fast pass. After I looked over the repaired fender, it was ever so slightly touching the wheel. I adjusted it and ran the car 6 more times and it ran a 2.950 avg with a 2.948 fast pass. The car has been taken apart and rear cones added. A new set of 91 SGA's will go on along with a new set of modified wheels to allow the wheels to be turned around along with a new fresh set of fenders. Hopefully, I'll be able to test it by early next week.
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psycaz
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Re: 2010 Test cars

Post by psycaz »

Would you care to share any info on the wind deflector for the raised wheel?

Curious as to what material is being used and how it is attached.

Did you make your own flares or use a preformed set?

Thanks for sharing the info.
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FatSebastian
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Re: 2010 Test cars

Post by FatSebastian »

Grubartez wrote:What I can tell you is I sent out a car with basically the same design and shape and wheels. ...
Thanks much for the data, Grubartez. Another question is whether adding fenders to an already fast car offers any advantage on final times. Sporty claims to "have tried this in the past and had no real gains," and based on your testimony there seems to be some risk associated with their use. So how does one know that fenders are providing measurable improvement? :/ I suppose the only way to test this is to run a control car with and without fenders?
psycaz wrote:Would you care to share any info on the wind deflector for the raised wheel?
:nod: Yes, psycaz is not the only one who is curious about that.
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Re: 2010 Test cars

Post by Grubartez »

FatSebastian wrote:
Grubartez wrote:What I can tell you is I sent out a car with basically the same design and shape and wheels. ...
Thanks much for the data, Grubartez. Another question is whether adding fenders to an already fast car offers any advantage on final times. Sporty claims to "have tried this in the past and had no real gains," and based on your testimony there seems to be some risk associated with their use. So how does one know that fenders are providing measurable improvement? :/ I suppose the only way to test this is to run a control car with and without fenders.
psycaz wrote:Would you care to share any info on the wind deflector for the raised wheel?
:nod: Yes, psycaz is not the only one who is curious about that.
Without the fenders, the car is about 0.01 seconds slower.

As for the wind deflector, I turned the front raised wheel around and covered the open area with clear packing tape. I don't know what LA used on his wheel.
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psycaz
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Re: 2010 Test cars

Post by psycaz »

Thanks for the info.

Not sure if I could run tape on the wheel to seal it off, but interesting none the less.
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FatSebastian
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Re: 2010 Test cars

Post by FatSebastian »

Grubartez wrote:Without the fenders, the car is about 0.01 seconds slower.
Thanks much for the quantification, Grubartez.

For anyone who knows, I'm still curious about this:
FatSebastian wrote:what is the supposed advantage of turning the sidewalls inward? :scratching:
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pwrd by tungsten
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Re: 2010 Test cars

Post by pwrd by tungsten »

FatSebastian wrote:
Grubartez wrote:Without the fenders, the car is about 0.01 seconds slower.
Thanks much for the quantification, Grubartez.

For anyone who knows, I'm still curious about this:
FatSebastian wrote:what is the supposed advantage of turning the sidewalls inward? :scratching:
I have had awhile to think about this.

1) stiffer - maybe not for unlightened wheels but for lighter ones for sure

2) rounder - when canted the tread no longer comes into play. Any variation in width would cause lack ofroundness

Just my thoughts.
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sporty
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Re: 2010 Test cars

Post by sporty »

League racing is not the same as cub scouts.

league rules are different in some ways and in many ways.

having a track and timer and knowledge is key.

I have a few faster cars now, but swith having to run 4 wheels on the ground, does not compare to a 3 wheel car.

I can get a three wheel car to go pretty darn fast. but not as fast as my 4 wheel cars.

But those guys are the best of the best that are racing in leagues.

So sporty is just a good scout comparison.

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Re: 2010 Test cars

Post by quadad »

When looking at this car (and it does look really neat :bigups: ), I am reminded of one simple question - Why do many of the cars with fenders have only rear fenders ? Aren't the front wheels causing more air to be displaced ? Aren't the rears protected by the fronts some ?
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Re: 2010 Test cars

Post by gpraceman »

If you guys wish to discuss league cars, times, records, rules, etc. then it would be best to head over to one of the league forums.
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psycaz
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Re: 2010 Test cars

Post by psycaz »

Randy,

Is it ok to continue discussing the pros and cons of the rear fenders, and possibly front, since those are allowed by most scout rules?
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