11 replies to this topic

[JimF]

OK.....here's a sorta catch all update on the Can Ams that I've posted on lately. This will also show how one thing led to another.

 

First.....The "No Brainer"

• This is the latest version, and still the go anywhere chassis. This is 4.050 wb X .090 gl.
• This one would go about 106 gr. all up with the center weight out. Good for flatter speedways and hillclimbs.
• The center weight adds roughly 10 gr. for flat track applications. Good also for shorter hillclimbs.

 

Next is the first "short-light"

• This is 5X .047 soldered full length. This is 3.875 wb X .875 gl.
• This goes about 92 gr. all up and is very good on a Gerding King @ Buena Park.
• This is pretty good on flatter speedway tracks. Very fast but a little edgy to drive.
• Adding some weight to this and getting it to 98-100 made it much better on most flatter speedways.

 

Next up came the 2nd "short-light"

• Following up on the above car, I built this one intentionally heavier (98 all up) so that I could leave #1 lighter.
• Dimensions are the same, rail menu is the same but the rails are not soldered full length.
• So far, this one is a little more stable exiting the bank on faster tracks. Also easier to drive.
• This has been raced once on a swoopy hillclimb and was the best car I've ever had at that track.
• Right now, this is my "go to" for our faster tracks.

 

After the two short cars, I built this with a different goal in mind (ie: flatter tracks)

• This is the "hybrid" 8 rails of .047 (2 wire > 4 brass > 2 wire) Outer wire rails are soldered, the rest not.
• This car is long (4.050 wb X .900 gl) and fairly heavy (109 gr all up)
• Boyoboy.....is this car schweet! This thing just about drives itself.
• This car is easy, smooth, handles great but is not exceptionally quick through the turns.

 

So......I thought, "what if I could combine the quickness of the short cars with the schmoove on the hybrid?

• This is the same dimensions and approx weight of the two short cars above.
• But....rail setup is 5/side (1wire .055 > 3 brass .047 > 1wire .055) All rails are soldered front and rear only.
• So.................it didn't exactly work.
• Not that didn't run well, it did. Just didn't offer the schmoove of the first hybrid.
• This car was really very good. But it wasn't any better than the first two "short-lights"

 

 

Which all brought me to this.........full on hybrid rail layup in a short car that is slightly lighter than the original.

• This is same 8 rail layup as the original but 3.875 X .875.
• This one goes 104 gr. all up.
• Haven't tried it yet so whoooooooknooooows??

[Tom Eatherly]

Well, we know the "No-Brainer" works. Anybody can just ask TJ Alba or myself how they work on BPR's flattrack.

Pretty much retired my older flattrack Can-Am.

[JimF]

Well, we know the "No-Brainer" works. Anybody can just ask TJ Alba or myself how they work on BPR's flattrack.

Pretty much retired my older flattrack Can-Am.

 

Yep....it really does work. Last time down there, I had the 8 rail as shown above and the "NB" as my main Can Am choices. It turned out that I ran an anglewinder coupe but had I chosen to run a regular Can Am.....the "NB" was better on that day than any other inline I had. Just shows to go ya that simpler can also be better sometimes. The one shown here is NB-7 and is destined for another So Cal guy.

[Tom Eatherly]

Well, whoever it may be, they're gonna really like it. Dang! More competition!

[Samiam]

Jim,

I see mounts for floating center weights. Is this for flat track use?

[JimF]

Jim,

I see mounts for floating center weights. Is this for flat track use?

 

Not primarily for flat tracks but allows the possibility for center weight pans just in case I run them on flat tracks or if I feel the need on a flatter speedway.

[JimF]

And, an additional development............

 

So this chassis, my first short-light hybrid, was very good but no better than the other two. I figured I didn't need three, so I'd sell this one. But then, I thought "why not re-purpose it?"

 

 

 

So......that one (above) became this one (below)

 

 

 

• Pushed the nosepiece forward.
• Made a new front end.
• Made new (heavier) pans.
• So it went from 3 7/8 X 7/8, 96 gr, to 4" X .925 & 104 gr.
• Should be very good on all our speedways and really good on flat tracks with a little weight on the pans.
• Yay.......a brand new car in about an hour.

 

LOTTA testing to do now..............

[Tim Neja]

So does this mean you LIKE the brass / piano wire hybrid rails?  Do they add flex and additional dampening for vibration?  Art they making more bite?  Whaddya think??

[JimF]

I do like 'em.....a lot. I think what they do specifically depends upon how they are configured. I think they can add more flex and thus make more bite but then again.....not necessarily.

 

Frinstance..........

 

• The justly famous "Samson Rail" F-1 is not necessarily a high bite frame but it's very effective, damp, and easy to drive which means a lot.
• I think a 4-5 rail of .047 or a 7 rail of .039 will make more bite in an F-1. Not necessarily as easy to drive.
• The recent hybrid rail stock car I posted on is the best stock car I've built and not real bitey (Samson rail copy)
• The 8 rail hybrid posted above (the long, heavy one) is smooth as glass. Maybe the smoothest Can Am I've built. Medium bite.
• Can't say about the short 8 rail or this stretched out one yet but will know soon enough.
• Planning a Semi-Samson rail Can Am next although it might turn out to be some kinda tripodish thing.

[Tim Neja]

Saw a couple of your "no brainer" cars today at BPR on the flat track!! They were working very nicely!! Good smooth driving cars---nice job Jim!

[JimF]

First test results..............................

 

All the above cars along with the short "No Brainer" were tested yesterday on the King Track at Eddie's Slot car World in Vallejo Ca. This is a semi- swoopy King in the older (pre Gerding) style. This is a pretty old track and is showing some age but it is still one of our fastest (relative term) tracks.

 

To recap: The goal was to take the speed of the #2 short light and combine that with the smooth and easy feel of the 8 rail hybrid.

 

Short-light no brainer: (pictured in another thread)

 

• Very good, quicker than the original long version.
• Initially, the fastest of the bunch, and the easiest in tire selection. Everything worked.
• As the bite came up over the course of the day, it became a little critical on turn exit in the donut.
• Later in the day, this car probably needed narrower tires.
• Probably a little too light @ 96 gr all up.

 

Stretched out 5 rail:

 

• Very good car as a stand alone. Drove like a longer car (which it is)
• More critical in tire choice as this car had the most bite of this batch.
• Really good but missed the mark for this narrowly targeted test.

 

Original 8 rail (long)

 

• Still very smooth, easy, and forgiving.
• Good racecar with JK 8703 or 8713 PP (or) with 8703 PT.
• Just not quite as quick through the turns as SL#2 but much easier.

 

Shorter-lighter 8 rail:

 

• This one hit the mark.
• This frame had almost all the ease and forgiveness of the long version, but was quicker.
• Tested with the same motor and body, this car was about 1 tenth faster than the original.
• It did have the characteristics of a shorter car but was more controllable on turn exit than SL#2
• Not quite as fast as SL #2 but I think it'd do more laps in 32 mins.
• This car wanted 8703 or 8713 PP, treateds were not the sweet spot for this one.

 

I guess no surprise here. I wanted the smooth of the original 8 rail and the way to get it was another 8 rail just shorter and lighter. I think this car can be built as light as maybe 100 grams or slightly less but I'm not sure that I have any need to do so. The wheelbase and guide length felt about right. (although maybe a tiny bit longer guide lead would ease the turn exit a bit)

[Mark Wampler]

Nice work Jim.  I'm sure us builders out here are def paying attention.  Your rides were pretty sweet on the Flatster this time around.