453 replies to this topic

[Alan Draht]

The Neo magnet's strength was such that when you turned the rear wheels or the armature, there was a ratchet or "cog" effect.

 

The re-magnetized vintage Alnico magnet produces none of that cog effect.

 

So I asked Mike, "Is this stock Ram motor magnet that's just been zapped as strong now as it would have been after it was zapped 55 years ago?"

 

In other words, is the fully-zapped magnet in my dragster's motor as strong as Gene Husting's was after he zapped his, theoretically speaking?

 

More than that, is my re-magnetized magnet and replicated motor capable of achieving Gene Husting's record-setting times, all other things being equal, even though the magnet doesn't "feel" much stronger than before?

[Alan Draht]

When I posed those questions to Mike, he said the "cog effect" doesn't mean the motor has been further optimized.

 

It depends on the motor's design, on how the magnet's magnetic field is concentrated/ focused on the armature, among other things.

 

The ultimate test is to put the car down on the track and run it.

 

The thing is, I wasn't prepared to run the car that day.

 

I have more work to do on the tire front for the Husting replica dragster.

 

I've got one good pair of Graupner tires mounted.  By "good" I mean that the tires are mounted true on the Russkit wheels and don't wobble.  I have two more pairs of Graupners tires mounted, but they wobble and that can't be a good thing for a dragster.  So, I have to soak those tires off of their rims and start over, being careful next time to mount/ glue the Graupners on straight, not crooked.

 

When I've got four or five pairs of "good" trued tires mounted correctly, I'll return to Mike's facility to track-test the car systematically, similar to how Gene Husting developed his tire program and optimized his car's performance in 1966.

[Alan Draht]

Back to testing my Pittman-powered aluminum channel/ front suspension cars, the modern re-creations of Howie's car... on the flat track.

 

I tried gearing up to increase top speed, since the cars sounded like they were winding out 1/3rd of the way down the straight.

 

But, there was no improvement in straightway speed.

 

So, I put those cars away and instead tested a wide array of slot cars that I had brought with me, including 1970's angle-winders and modern Retro CanAm and F1 cars.

[Alan Draht]

So, what did I learn?

 

I learned that there's such a thing as a magnet that's too strong for a given motor design.

 

Both of my Pittman-powered cars have Neo magnets in them and they are slow on the straight because sheer magnetic strength kills their rpm's.  The Pittman 6-volt armatures in the open frame configuration aren't strong enough to overcome the Neo magnet's resistance to the arm's turning force.

 

Gearing up made no difference with these cars.  They ran hotter.

 

In order to optimize the Pittman motors in these two cars, I need to build another pair of Pittman motors with stock Alnico magnets installed and re-magnetize them before my next track outing.  My guess is that these cars will run faster as a result.

 

The same holds true for the dragster.

 

The Ram motor's zapped stock Alnico magnet should be at full strength now, theoretically, and the car, all things being equal, should perform as well as Gene Husting's did in 1966.

 

Time and more testing will tell.

[MSwiss]

The Neo magnet's strength was such that when you turned the rear wheels or the armature, there was a ratchet or "cog" effect.

 

The re-magnetized vintage Alnico magnet produces none of that cog effect.

 

So I asked Mike, "Is this stock Ram motor magnet that's just been zapped as strong now as it would have been after it was zapped 55 years ago?"

 

In other words, Is the fully zapped magnet in my dragster's motor as strong as Gene Husting's was after he zapped it, theoretically speaking?

 

Is my re-magnetized magnet and replicated motor capable of achieving Gene Husting's record-setting times, all other things being equal, even though the magnet doesn't "feel" much stronger than before?

I have no idea how a new motor cogged back in 1965(?).

 

2 important things.

 

The zapping resulted in a large increase.

 

Mark Mattei has exhibited a complete vintage motor is capable of those times, even on 16V.

 

He has gone 1.10 at 55mph, and has never made, IMO, anywhere a clean pass.

 

There hasn't been a reason to raise the power above 16V, because his car isn't sorted out.

 

In your case, if your car ran smoothly, but just a bit slow, there isn't any reason not to turn up the power.

 

Putting the NEO mag in , defeats the purpose.

 

Someone has gone sub 1, on 16V, with the NEO mag, and IIRC, modern tires.

 

Cool, but not nearly the same as going sub 1 with all vintage style equipment.

 

Just like if Mark goes sub 1, with the vintage motor, but a modern guide and tires.

 

Cool, but way cooler, when he switches back to a vintage guide and tires.

[Alan Draht]

I totally agree.

 

The only reason I used Neo magnets in the Pittman-powered Howie "rocketship" cars is because at the time I built them there was no answer to my call and search for a good old-fashioned slot car magnet zapper.

[Alan Draht]

About the Husting dragster's braid and guide..

 

The guide is a Corben and I think it's made for drag racing, but I'm probably wrong about that.

 

Anyway, Husting talked about using a Russkit guide in his car.  That's what the photos show.  It's typical in size to the majority of guides available to choose from in those days.

 

Gene drilled a 1/8" hole in the back of the Russkit guide and inserted the end of the swing arm's 1/8" aluminum tube into the hole and  epoxied it.  I didn't use that detail in the construction of my car's swing arm and guide attachment.

 

The braid is is specifically the "hairy" type which all mid-1960's drag racers seemed to prefer.  It comes in twisted strands like copper lamp cord wire which you cut to size and insert into the guide.

 

I haven't untwisted the braid yet in my car.  I will when I'm ready to test it on the drag strip.  I expect it will work fine since the car is built almost exactly the same as Husting's.

[Dave Crevie]

The "stranded" braid was sold by several companies, IIRC. I used it, but at voltages 24 and higher, it was really only good for one run. The fast guys used,

it and just accepted the fact that they would have to change after each all-out pass. In my town we had a radio shop that sold 14 guage silvered stranded

wire, that I just stripped the rubber insulation off of. At the time, everyone was convinced that silvered braid was the way to go. I still have some to be used

on some of my vintage resurrections. But it is real stiff by today's standards. Hard to believe that, when used with the shorter blade depths of the time, the

cars would actually stay in the slot.  

[Alan Draht]

About three weeks ago I visited Mike Swiss's Chicagoland Raceway to test three vintage Top Eliminator dragsters.

 

I brought and tested the K&B aluminum railed dragster equipped with a 6 volt Pittman motor and modern Pro-Track rear wheels/ tires.  I restored and upgraded this K&B kit chassis from the mid-1960's.  I had the parts and wanted to make the car track-worthy.

 

I primarily wanted to see if a vintage 1960's dragster weighing +/- 7 oz. it would stop before hitting the wall.  These vintage dragsters are physically larger and way heavier than today's typical scale dragster slot cars

 

In other words, this car is my "crash test dummy".  If it ends up in a wad at the end the drag strip should it hit something, it's not the end of the world.

 

I tested the car at a fairly low voltage (12 volts? I don't recall).  The modern Pro-Track rubber did not hook up well at all on the track's surface. The rear end hopped all the way.  Elapsed times were slow.

 

I ran it two or three times and then put it away.  I learned that a dragster that size and weight could stop safely, at low voltages anyway. My objective achieved, I felt comfortable about testing the Husting and Maldonado dragsters, which was my primary testing goal that day.

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[Isaac S.]

From what I know the cars have too much traction with the Pro-tracks because the car has lots of weight on the rears. Germans are regularly faster on these cars. 

[Alan Draht]

Since I have two separate classic vintage dragster build threads on Slotblog -- one for the Gene Husting car and the other for Manuel Maldonado's car -- I will post test reports for each car separately on its respective thread as well.

 

This report from that track test session is for the Husting dragster.

[Alan Draht]

So, construction of this car replicates the build process and design details of Gene Husting's 1966 sub-zero record-setting mag rail dragster, as written up that year by Gene in a series of Rod & Custom articles.

 

R&C also sponsored a series of important drag racing events on the West Coast in 1966, where many of the great Pro slot car drag racers showed up to compete, including Husting and Maldonado.

 

The build process for this car is detailed earlier in this thread.

[Alan Draht]

The test session at Mike's track facility a few weeks ago was the first time that this car had been put down on a drag strip.

 

It was equipped with a Ram 6 volt arm, new unseated Pittman brushes, and a single medium-tension spring.

 

The car used a 64 pitch, 69T spur gear with a 23T pinion, for a 3:1 drive ratio.

 

The car ran/ runs on Graupner 62-Shore hardness tires mounted on vintage Russkit dragster rims.  Just like Gene, I cleaned the tires with naptha.  In the 1960's Gene used Energine -- a product which was simply naptha sold as common household spot remover.  Dry cleaners used it, too.

 

There was a 1 oz. lead weight in the nose of the car.

 

The car had a vintage Cor-Ben drag racing pick-up guide with a double strand of "hairy" uncoiled braid on each side of the guide's mini-blade.

 

Those were the key variables, I think.

 

Oh, this is key, too:  The slot car drag strip track surfaces of the 1960's were cleaned down with naptha by Pro's like Gene before every run.

 

Today, drag strip track surfaces have glue residue from the shut-down section's glue trap.  Drag racers may roll their dragster's rear tires on a piece of cardboard at the starting line by way of cleaning excess glue from their previous run.  The track surface is not wiped down with naptha.

 

Everything on the car can be perfectly correct in terms of replicating vintage chassis construction details, tires and techniques, but the fact remains, the track conditions of the 1960's slot car drag strips, where Pro's tested/ competed in R&C's drag meets, cannot be duplicated today.

[don.siegel]

 

 

R&C also sponsored a series of important drag racing events on the West Coast in 1966, where many of the great Pro slot car drag racers showed up to compete, including Husting and Maldonado.

 

 

 

Alan, 

As far as I know, Rod & Custom covered those drag meets in 1966, but they didn't sponsor them; it was the individual raceways that organized those meets, like J&J. Rod & Custom did sponsor a few of the early one, in 1961-63 I believe, to get the ball rolling, but after that there were hobby shops/raceways that continued. In 1966, R&C did sponsor the first road race series that kicked off pro racing. 

 

Don 

[Alan Draht]

I don't remember the elapsed times exactly.  I was busy with the car and didn't photograph the digital results board.

 

The first couple of runs may have been in the 1.5 - 1.6 second range.  Brushes were not seated yet.

 

I was particularly impressed with the performance of the Graupner tires.  They seemed to hook up to the track's surface almost immediately.  (Of course, glue residue may have had something to do with that).

 

It seems that this important variable, which gave Gene Husting and his fellow Pro drag racers a lot of trouble with tuning these dragsters in the 1960's, is not going to be a problem today.

 

Times went down steadily in subsequent runs as the brushes began to seat properly, improving power delivery.  That's my theory at least.

 

By the 5th or 6th run, the car was posting 1.2 and, maybe I recall, a 1. 19 second time.  At that point, voltage was set at 15, 18 or 20 volts?  (Mike S. might remember the details).

 

I was satisfied with the car's performance in its first test ever and ended the session.  I made a mental list of the things I wanted to do with the car to optimize its performance for the next test session.

[Alan Draht]

"Hairy" braid and, to a lesser extent, vintage drag racing pick-up guides are a royal pain to deal with.

 

The braid itself is unruly and requires constant grooming/ brushing to stay put.  The guide's tiny blade cannot prevent the +/- braid strands from touching and shorting out.

 

Mike Swiss, who had a better viewing angle of the car than I did standing behind the starting line, said that there was a lot of arcing at the pick-up guide on every run.  (And still, the car's elapsed times dropped steadily).

 

Anyhow, by the end of the day, replacing the vintage pick-up guide and "hairy" braid set-up was near the top of my list of changes to make to the car before its next test session. 

[Alan Draht]

At the top of my list of changes to make to both the Husting and Maldonado dragsters, is an item to install  .... 

 

                                                "The Widow Maker"

 

 

The Ram 3 volt arm ... 

 

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[Alan Draht]

I've got two 3 volt Ram armatures, one each for the Husting and Maldonado dragsters.

 

The arm on the right hand side of the photo in post #417 shows a 3 volt Ram arm sitting next to a Ram 6 volt arm for comparison.  The winding wire size difference tells the whole story.

[Alan Draht]

I went to work on the first item on my "to do" list soon after the first test session for both dragsters.

 

Here are the two Ram 3 volt arms epoxied.

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[Alan Draht]

Prepping the epoxied armatures for lathe work...

 

Center-drilling the arm's free end; then using a "live center" in the lathe's tailstock to support the free end...

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[Alan Draht]

The outside surface of the arm's seven metal segments were trued until all metal segments were machined to the same height and made concentric... 

 

 

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[Alan Draht]

Next, it was time to balance the armature...

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[Alan Draht]

After the arm was balanced, all of the steps necessary to install it in the motor were performed, including notching the right-hand shaft stub to accommodate the Weldun pinion gear's set screw.

 

Once installed, the Pittman brushes were re-set, but this time with stiff double springs, one inside the other.  In his R&C articles, Husting makes a point of experimenting with a variety of springs to fine-tune his motor's performance.

 

The final step in motor construction is to zap the Alnico magnet on the big "self-contained magnetizer".

[Alan Draht]

With the Ram 3 volt motor squared away in the Husting car, I turned my attention next to reducing the chassis's nose weight.

 

A 1 oz. lead nose weight had been installed in the car for its first test session.

 

Since there was nary a sign during that session of the car's nose lifting with the 6 volt armature installed as tested through 18 - 20 volt power levels, I decided to reduce nose weight for the second test session in conjunction with switching to a 3 volt arm.

 

This time around I moved away from casting low temp lead alloy to create new weights.  It's a cool process for the first few castings, but it's hit-or-miss as far as casting precise weights by design -- to create fractions of an ounce -- in lead alloy.

[Alan Draht]

So, I borrowed a page from a distant cousin to slot car racing -- Pine Box Derby racing -- to use tungsten ballast.

 

Tungsten is 1.7 times denser than lead.  A cube of tungsten, one inch on all sides, would weigh 0.70 lbs -- 1.74 times more than the same sized cube of lead, so it's more compact in size than lead is.

 

Here's a set of tungsten weights which come as a kit of 3/8 inch diameter round disks.

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