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Old 07-24-2007, 05:49 PM   #1681
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Originally Posted by yyhayyim View Post
Ran a pack today before getting rained out, w/ the front 5 deg blocks. The car seemed a bit twitchy on power, especially at higher speeds, but had less turn in than w/ the 10deg blocks...I dont like the twitchyness...so I'll be going back to the 10 deg and wait for the .20 springs comming in this week.

One problem: the Spur gear stripped. Very strange, its the 2nd Spur gear that strips on 3 runs...I'm using 64P 100T spur gear and Robinson alum pinions...any clues as why this could be happening?

I'm going to try 48P gears now...any one know the 48P equivalent in size(or closest) to 100t 64P Spur?
use this quick formula to convert gear pitch sizes...

(spur size / current pitch) * desired pitch = spur size of desired pitch

(100 / 64) * 48 = 75

you would need a 75t 48p spur
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Old 07-24-2007, 06:51 PM   #1682
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RUssB- thanks for the tip...now to order some Spur gears..
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Old 07-24-2007, 06:54 PM   #1683
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Originally Posted by yyhayyim View Post
Ran a pack today before getting rained out, w/ the front 5 deg blocks. The car seemed a bit twitchy on power, especially at higher speeds, but had less turn in than w/ the 10deg blocks...I dont like the twitchyness...so I'll be going back to the 10 deg and wait for the .20 springs comming in this week.

One problem: the Spur gear stripped. Very strange, its the 2nd Spur gear that strips on 3 runs...I'm using 64P 100T spur gear and Robinson alum pinions...any clues as why this could be happening?

I'm going to try 48P gears now...any one know the 48P equivalent in size(or closest) to 100t 64P Spur?
there is nothing wrong with 64 pitch
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Old 07-24-2007, 07:51 PM   #1684
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there is nothing wrong with 64 pitch
I know...I prefer 48P though
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Old 07-24-2007, 08:00 PM   #1685
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there is nothing wrong with 64 pitch
till you get a love tap in hte rear.. then your running no pitch...
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Old 07-24-2007, 09:33 PM   #1686
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Originally Posted by John Stranahan View Post
Pan Car Speed Run 63 mph! (Using Track Gearing)

We finally had a dry day and went out to Houston Raceway park which is a multi million dollar 1/4 mile dragstrip. 1/4 mile of grandstands on both sides of the track. 5 story VIP motel right behind the starting line. The race cars all pass through a tunnel in this building this is where we pitted in the shade.
The track is concrete. It is covered with a layer of thick rubber and VHT traction additive. When you walk on it you stick to the ground. For the pan car it was another story. The top surface has no real texture too it, that the foam tires rely on for traction. I had a lot of trouble driving straight from poor traction. I had the Novak 3.5 R geared 13/90 which is suitable for use on our track. I got my best speed of 63 mph. The body was very similar to what the guys use in Europe at this point.
I had much better luck with the blowovers. I tested two items, front corner winglets and front corner diffusers. With both of these on board the car was very squirrely. I could not drive it well (I can't drive from the ground anyway) I crashed it. I took the winglets off and the car was better. It did not go airborne unless I hit an expansion joint that was not even. The reason for the improvement was a pair of front diffussers like on the Toyota Eagle MK III. Pic below. The theory here is that the front tires pull considerable air under the front bumper from their rotation. The air expands under the diffuser and creates a little vacuum there. This is worth a test on the track. Now I will just say that the car was not really topped out on this 63 mph run. More gains are possible. With the lack of traction and lack of a drivers stand my Radio range limited things again.
Radio range was 130 yards on the ground. 150 yards about 3 feet up on the concrete K-rails. Old Spectrum receiver with long antenna.
What a cool place to drive your speed run car. Nick might post a video or two we will see.
John
Here are the pics and video from our testing:










Video here
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Old 07-25-2007, 03:30 PM   #1687
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Here's an interesting recent video of a pan car at indoor track being tested with mamba max a nd 700 motor w/ 3s lipo...

http://www.youtube.com/watch?v=ANaIqQxKqqU
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Old 07-25-2007, 07:02 PM   #1688
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i wonder if capps would hook better on that dragstrip...
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Old 07-25-2007, 09:11 PM   #1689
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i've not heard anyone else having problems on a drag strip.. they did the fast speed runs at one last year. somebody must have figured it out.
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Old 07-26-2007, 04:00 AM   #1690
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..I personally would be testing with CAPS - not FOAMS simply for rolling resistance if nothing else. (BSR is now designing a NEW cap to be used with LIPO MOD racing on VELODROMES to better handle the speeds)

BUT - I don't understand how you guys are driving these things with SOOOOOOOOOOO much steering or Why? They are freakin SQUIRRLEY~

Crank up the CASTER - dial down the Dual Rate - make it so you can NOT make a U-TURN on the track w/o using a OPPPS Button (if the radio is equipped) You are not trying to run a road course...you don't want/need steering.

Make the car track straight - and NOT want to turn (which is why I always tell guys doing insane cars...NOT to use HD front end bodies) TOO much HIGH SPEED Steering.

Since you guys appear to have a TON of power - a little TOE OUT along with a TON (12-15 degrees) of caster would help keep the car straight. The SCRUB you will get from the TOE OUT will be outweighed by the STRAIGHT LINE stability of the car (don't go too wild...just a little) I would use OFF CENTER Steering blocks too - to take away steering sensitivity.
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Old 07-26-2007, 09:39 AM   #1691
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The speed runs are not their primary deal (except for the monster) - John runs road course with it.

Caster is not very adjustable (usually derived from a dynamic AE kingpin front end) and toe-out is a recipe for disaster on these - stability is from toe in, not toe out on our cars.

All that said - he's likely squirrelly on that run because the surface is dusty - it looks like he can't get rear traction.
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Old 07-26-2007, 10:13 AM   #1692
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Caster on the AE dynamic front ends can be be adusted. The guys at the swtour are running up to 10 degree caster to keep the thing tracking. Go talk to Nick Case about setting the front ends up. the optional tower can converted the dynamic action to fixed. you can move the little washers to make more caster, also spacers under the mounting plate can increase it more.

caps are the way to go. foams will probably chunk or explode at over 100 mph. Super hard foams may work. however with caps it is difficult to launch the car off the line. it takes a throuttle finess to get it off the line. this all can be done and has been done.

I expect a lot of spin outs from what I've been hearing. listen to SWT for tips for high speed handling, areo and suspension set ups. this is all totally different than road course set ups. you want to go straight as opposed to corning. those swoopy noses on the gtp bodies look deceivingly fast, but create way to much downforce. I still think a pan car chassis with a body designed for Velo racing is the way to go. these body shapes have been proven stable at hi speeds. for example mccallister makes a hi speed dodge body with a blunt nose and very low roof line. further, I have witnessed nick case doing 8 second lap times at the Velodrome with a velo body, the car was perfectly stable.

I wish the best of luck for all of you, and I hope all of your ideas pan out.
I'll be taking notes this year, next year i'll throw a couple of battery packs into my velo car and give it a run.

by the way we run on a dusty bicycle track with no VHt nor tractiion compound of any kind. in addition it is concrete with expansion strip bumps.

One last thing tow out will make the car stable on the straight. straight line handling set up and pan car set ups go against every on road rule.

Joe Myers knows what he is talking about on straight line handling, we are not just blowing smoke out of our tail pipes.
wn

Last edited by nagatahawk; 07-26-2007 at 10:26 AM.
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Old 07-26-2007, 11:23 AM   #1693
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There's a Pantoura for sale on RCTECH.NET if anyone is interested...
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Old 07-26-2007, 11:58 AM   #1694
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Boomer has described my situation dead on. The lack of rear traction made the car squirrely. Every time I slip a tire just a little it will drive the car crooked.

I think caps would be the way to go at the dragstrip. The rubber relies more on molecular adhesion for grip than the foam. I think the rubber tires would have had good traction on this VHT treated rubber surface.

I am just the support crew. I bring my car with very few mods just for fun. No serious speed attempt with me. Same gearing I have used on the track occasionally.

I do think that my car was not topped out due to traction problems.

If the front of my pan body had serious front downforce it would not tend to fly at high speeds. The wind tunnel told the same tale. Not much front downforce. Plenty of rear downforce in the back for the stock body GTP. I think you guys are mistaken here.

I did run a Gurney strip which Drew Pioneered here. I did not do as neet a job constructing it as he did.

I might test one more time in front of my house when Nick gets through with the radar.

I am getting a pair of spectrum lap timing equipment modules to do further tests on the Powell wide chassis as well as on my own.

I have also had an interesting new development. I will be doing some Prototype testing for Novak. You will not be able to read the results here though.

64 pitch gears just don't hold up on a 1/10 pan outdoors. Neither will an Aluminum pinion. Get some hardened steel pinions, preferably hardcoated ones. Use 48 pitch spurs.

John
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Old 07-27-2007, 10:04 AM   #1695
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John - hmmm, well I'll go back through and cover up my vents, then, and see what comes of it.

In any case, you've found what we've found around here - that 48p is the way to go outside, oval notwithstanding.


btw - Nagata - on road course, toe out increases turnin and decreases stability; toe in decreases turnin and increases stability. This is because of ackerman angles and we do find it to be true. Toe out the front and we wander, toe in and we're stable but we don't have the responsiveness. Most that I know use 0deg.

Obviously you're an oval guy. Welcome to Right Turns!
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