BSA Car Tips

[W racing]

Derby time is aproaching so here are some tips for 2012. Hopefully others will pitch in with their favorite tips.

Properly drilled holes are the foundation of a fast car. Use the Silver Bullet.

READ and understand the rules of the race.

Ask the race officials if you have questions... (Get answers in writting if possible)

Determine the following:

Can I:

Drill holes or do I need to use slots (Holes are better, use The Block to drill them.)

If I can drill holes can I extend the wheel base (Extended faster)

Can I use any axles or only BSA axles (Most races will require BSA axles). DD4H axles are the fastest available if your rules allow them...

Can I taper the heads of the axles? This is a rule that some folks will cheat on by tapering 1-2 degrees. Not enforcable and not a good rule... However if you have the rule make sure your axles heads are not tapered.... (rare rule fortunately)

Can I raise a front wheel (3 wheels touching) recomended

ADVANCED QUESTIONS:

Can I cant rear wheels?

Can I railride (Run the rail ;D).

Maybe too advanced. Just ask if it is allowed. You can make a fast car without these.... However faster car if you can do them...

TIPS:

ALIGNMENT IS KEY TO WINNING:

If you can drill axle holes. Drill them perfect. This is the foundation of the car. and the foundation of your alignment.

The Silver Bullet allows you to drill perfect holes...

EXCESS WOOD: Cars with excess wood make it harder to get the COM right. Cars in the 0.6 - 1.2 ounce range work best. Good to have 3.5 ounces of concentrated weight if you can get it. (Lighter cars will work as well... However it is not necessary and BSA cars often run with brutal stop sections so the cars need to be a bit robust)

CAR NOSE:

You should have a 1/2 flat area on the center front of your car for the starting pin and for the finish line.

If you can extend the wheel base do so...

Rear axle back as far as possible 5/8. Front axle 7/8 back to protect against rough BSA stop sections.

If you can not extend the wheel base can you chop the rear 1/4 inch of the block off and glue to the front? Ask the race folks...

Folks sweat over COM...

Not as important as alignment. If this is your first car start at 3/4"

Build a test car to get the COM correct. Weight should be all in one place near the rear axle...

Most people make the mistake of chasing a certain COM and adding weight all over the car. Dont do this...

Once you get a working design prototype car with correct COM. Start making the real car...

If money allows use Tungsten Disc or tungsten cubes.

Place the weight near or around the rear axle.

FOR BSA races be careful to not cut the axles on your car unless the race officials allow it. Even then keep the tips of the axles as proof.

Allow 3 weeks to build car if possible.

Father / son takes more time to mesh schedules. Paint two weeks before race if possible...

Skip paint on bottom of car to save time...

Prep an extra wheel and axle or two for a crash on race day...

Use DD4H graphite and polish kit. Oil DVD if allowed.

If you railride (Run the rail ;D) Have fun. Post questions. No one will know who you are

 

[OPARENNEN]

In addition to the above posting from W Racing for BSA races:

PRIME PRIORITY = Wheel and axle prep (no matter which axles you have to use, BSA or aftermarket like DD4H). If oil prohibited, eliminate Teflon, Jigaloo, Blue Thunder, etc. from last axle preparation step. AND eliminate the polish on the wheel bores, but make them both shine like mirrors.

2nd HIGHEST = Veer (drift) towards non-dominant side. I.e. Rail Riding.
12-13 inches on aluminum tracks. 3-4 inches on Wood Tracks (less on real rough wood tracks).

3rd HIGHEST = Axle holes in body = must be super accurate. Best method, drill holes just above the slots, remove half the wood from the bottom, but leaving slot impressions. Axle angle based upon Rules, but be exact, whatever the rule. Take as much wood from the top a possible, but not more than 1/4 inch thick.

4th HIGHEST = Weight placement (just B4 & after the rear axle). Tungsten is best by far, Lead 2nd best. Stay away from Zinc, I have never tried steel.

5th HIGHEST = Body shape = aerodynamics. If all of the above done meticulously, any thing is OK, especially if Scout desires fancy stuff. Best is flat wedge, not more than 1/4 inch thick, but car will perform well even with fancy stuff.

With that being said, I have 5 grandsons, all of which want to continue to be 1st place, and all of them in different BSA councils

A couple of times I have erred badly by not reading the rules carefully from each council, and if necessary, a call to the Pinewood Director in that council. E.g. Twice I found out that using the BSA wood block was not enforced, and in one council, they specifically said they would not enforce the axle in the slot rule, only that holes must be in same relative location.

This what I found out for each of the 5 councils:

1. Any wheels OK as long as they are cut from the BSA original (such are available); Any axle distance between front and rear. Nothing about lubrication.
This boy ran away from everything by more than 18 inches. I am sure they will change their rules next year.

2. Almost identical to our Pure Stock or Street Stock rules, except they allowed the axles to be moved towards the rear, but with a 7 5/8" spread.

3. Horrible Rules. I call it "Four Flat on the Floor", i.e. all wheels must touch, and no wheel can ride on the edge. I.e. no canting on any wheel. Flat means Flat, and they really enforced this during inspection. Also only graphite. Absolute best advice: DD4H has a specially drilled block that will beat anything you try on your own, and it has slots. Earlier, I drilled four straight holes, and made sure 3 wheels were absolutely parallel to the body block. However, the NDF wheel, although it touched the track, it had very little weight on it. You could press down on that side, adn the car went down, nevertheless, the wheel still touched, even when not pressed. It passed Tech. Then I bent the DFW axle very very slightly, but enough to make the car drift. It placed first, but probably more because of the wheel bore and axle prep.

4. Identical to 3. except canting allowed. Same procedures.

5. Identical to 2. except that axle spacing exactly the same as the block slots.

A. Oil vs. Graphite. Never change over from one to the other, especially from graphite to oil. Your car will crawl. If your conscience allows, use oil sparingly according to DD4H procedures, then put graphite on the wheel bottom and outside surfaces, keeping very clear from the axles or bores.

Some councils in trying to avoid the mess, prohibit Graphite, but require a powder. No advice here, since I know of no good powder. Use Oil process from above, and put white stuff on outside wheel surfaces.

 

[quadad]

Lots of good stuff so far here to help people. One common thing that I think many people overlook however is that even if the rules say your wheels have to be "flat", you can still drill a negative cant in the rear. You can only however use an angle that is less than the 'slop' available in the axle bore (somewhere in the 1 - 1.5 degrees range). Unless they specifically say that the axles have to be flat, this is legal and I think faster than flat rear axles.

Also, while I think that "The Block" is a neat tool, its not the end all. You still need to place it on a drill press table that is perfectly square to the drill. You still need a very good drill bit (I recommend solid carbide). It does take out some of the irregularities with the wood - and that's a real plus. Besides, I don't think many Scout families are going to buy it, unless they are really serious about PWD.

 

[Quicktimederby]

Your press table does not have to be perfectly square. Get it as close as possible but does not have to be perfect. However there can not be any end play in the press, and or press table. For perfect holes you have to use a high quality press. As for the squareness of the table I will leave that for John to explain, he's much better at putting it into words than I.

Also, while I think that "The Block" is a neat tool, its not the end all. You still need to place it on a drill press table that is perfectly square to the drill.

 

[cozybldr]

I would add that using Woods' Metal is also viable. The ability to pour in the weight and not have it burn the wood is great!