Can-Am Round #1 - The River Run

[Audi1]

Today is qualification day for the first Round in this series.

It's a beautiful, sunny day, the crowds are gathering and there's a lot of action in the pits after last night's Tech Inspection. All cars passed Tech; although some needed a part glued back on or firmed up in some cases prior to racing The clearance spec was the one that got the most attention. I use a 1.0mm piece of piano wire and if it will pass under the chassis of the car without causing it to move, then it's a pass. Clearances actually ran between 3.0mm and 1.0mm, so different tuners have different ideas on where to locate their COG with respect to the bottom of the tires and how best handle this particular spec.

Bob Bianchi can't make it today; due to an unexpected illness in his family, so yours truly will be running the cars. Stay "tuned" for results and comments and maybe some pics tonight.

I'm away all of next week so the race itself is booked for Sunday, May 20th.

Good luck to everyone in the qualy!

Allan

[cj74]

Looking forward to seeing how the MRRC stacks up to the souped up cars out there. :)

[Audi1]

Here are the results from today's qualy.

But first, here are some pics of the car before today's session:







It's a good looking field of cars!

And here are the cars on track, alphabetically, by marque:

The Alfa Tipo 33/3's:



The new BRW 154P:



The Chaparral 2E's:



The various Ferrari's; looking very much like a team:



The Holman & Moody "Honker" MRollingThunder comemmorative car:



The Lola "armada"; spyders and GTs:



The McLaren M6's and M8's:



The McKee "wedge":



The Porsche "army":



And the brand new Vanquish DN4:




And when the engines stopped and the dust settled, here's how they stacked up against each other today at the River Run:

Prior to the qualy, the track was washed, vac'd and tack clothed to remove dust. All cars were run for 10 practice laps to get the braids working optimally, to check out any driving issues and to get the controller dialed into the car. That was followed by another 10 laps for fastest lap time. The tires of each car were cleaned on a sticky pad prior to entry into the practices session, each time that they desloted and again when they entered into the qualy session. They were all run in the white (middle) lane and I did all of the driving.

A total of 34 cars were qualified. Two more are known to be in transit; one from Radarek and one from Mark. Both should be here before the start of the first race on May 20th, but will miss the qualy and will start the first race from the bottom of the qualy list.

Qualy Position / Car # / Racer / Car Type / Qualification 10-lap Fastest / 10-lap Average / Comments

34. / #19 / BARC-1 / Ferrari 350 / 7.703 / 20.00 / Very small guide, gearing tight, can brake traction on the straights
33. / #25 / glasshorsevh /McKee Mk10 / 7.628 / 7.71 / Shallow guide, deslots without warning, good straight line speed
32. / #47 / fc47 / Chaparral 2E / 7.321 / 7.43 / Tire chatter / very light / good brakes
31. / #20 / Duke7777 / Porsche 917PA / 7.071 / 7.22 / smooth, easy driver, a little loose in the rear
30. / #31 / Z-carfan / Lola Mk 3b / 6.980 / 7.14 / Great brakes, some tire chatter, stays in the slot
29. / #11 / cj47 / McLaren M6B / 6.974 / 7.15 / Little loose in the rear, some chatter, possible gear noise, easy driver
28. / #6 / Dogsbody / Lola T70 / 6.928 / 6.97 / Very noisy, spur gear likely rubbing against the chassis, predictable handling
27. / #7 / Pappy / Ferrari 512S / 6.890 / 7.04 / Nice car, very smooth, some chatter, can be pushed
26. / #12 / bov / McLaren M8D / 6.817 / 6.99 / Predictable handling, some chatter, easy driver
25. / #21 / Doubl-B / Porsche 917/30 / 6.812 / 6.97 / Big! some chatter, predictable, handles well
24. / #51 / pzooc / Lola T70, MkII / 6.745 / 6.83 / Good handing, some gear noise, easy driver
23. / #61 / Austin / Porsche 911 RSR / 6.742 / 6.94 / Plenty of power from the long can IL, predictable handling, some chatter
22. / #28 / arroldn / Ferrari 512S / 6.725 / 6.93 / Good brakes, some gear noise, can be pushed
21. / #1 / Changing-gearz / BRM 154P / 6.723 / 7.21 / Fast a straight line, some chatter, slight spurts and starts, predictable handling
20. / #9 / Mitch58 / Alfa T33/3 / 6.646 / 6.76 / Nice car, good speed, good brakes
19. / #13 / Beast Lee / Autocoast Ti-22 / 6.624 . 6.71 / Very smooth and quiet, easy driver
18. / #66 / ALS / Autocoast Ti-22 / 6.582 / 6.64 / Nice car, smooth handling, easy driver
17. / #32 / Alfa T33/3 / 6.500 / 6.60 / Good straight line speed, some chatter, can be pushed
16. / #33 / BrumosRSR / Porsche 911 RSR / 6.487 / 6.71 / Smooth, a little tippy, doesn't like to be pushed
15. / #17 / MRollingThunder / Holman & Moody "Honker" / 6.446 / 6.51 / Good car, good brakes, easy driver
14. / #99 / Billy boy / Lola T7- MkII / 6.388 / 6.43 / Great brakes! handles well, easy driver
13. / #16 / Alexis in Greece / Ferrari 612 / 6.359 / 6.59 / Good car, very fast, handles well
12. / #22 / rleog / Autocoast Ti-22 / 6.301 / 6.35 / Nice car, predictable handling, well balanced, easy driver
11. / #4 / cgingras / Lola t70 / 6.281 / 6.45 / Nice car, easy driver, very good brakes
10. / #23 / old23 / Lola T70 MkIII / 6.277 / 6.39 / Nice car, easy driver, can be pushed
9. / #65 / steeveew / Lola T70 / 6.131 / 6.18 / Good car, very smooth, fast, easy driver
8. / #5 / aloha / McLaren M8D / 6.097 / 6.13 / Nice car, good all-around performer, easy driver
7. / #30 / mether05 / Chaparral 2E / 6.092 / 6.21 / Very nice car, smooth, good brakes, easy driver
6. / #8 / Oscar Racing / McLaren M8D / 6.060 / 6.17 / Nice car, very fast, smooth, handles well
5. / #80 / Superslab / Lola T70 / 6.058 / 6.14 / Nice car, easy driver, can be pushed
4. / #3 / redlynr / Porsche 917k / 5.965 / 6.10 / Nice car, very smooth, just a little chatter, easy driver
3. / #10 / jscot111 / Porsche 917k / 5.857 / 5.97 / Nice car, very smooth, easy driver
2. / #2 / Audi1 / McLaren M8D / 5.777 / 5.87 / Home track advantage
1. #70 / Smokeio / Shadow DN4 / 5.591 / 5.69 / Amazing car! So easy to drive fast............

And there you have it; the first results from the 2018 MRollingThunder Can-Am series.

As you can see from the results, there are a lot of closely matched cars in this series. I added the 10-lap average in this time because it gives you an indication of how easy a car is to drive. If the average lap number is not too much higher than the fastest lap number, then the car is a very consistent performer. If there is more of a spread between the two, then the car tends to be a little harder to drive consistently.

One point that I'd like to make is that this qualy has demonstrated beyond a "Shadow" of a doubt in my mind, the 3DP cars have come of age. To have a 3DP car outperform some of the best performing injection molded plastic cars, like the NSR Porsche 917k's and the Slot.It McLaren M8D's is quite an achievement. Hats off to CG Slotcars for designing the Shadow DN4; simply a great running car.

Here's your qualy podium:



The first race is Sunday, May 20th. Stay tuned for the action!

Allan

[arroldn]

Wow Allan what a teaser!!!!!!!!!!!!!!!!!!!!!! 8-)

Hopefully the #28 had a respectable showing.

OK I'll give you a break. You just posted that post at 1:56. Maybe you are still posting. OK got to run to the grocery store. Maybe when I get back it will be complete.

[SuperSlab]

Shees Allan, this is very cruel! Are you just going to leave us dangling??

[Austin]

Can't wait to see if you can handle that motor in my Porsche.

[arroldn]

41 minutes and counting :|

We have results :D So I am at the bottom of the second third. Right on the bottom of the 2/3 mark :|

[alexis in greece]

Thanks Allan for the qualy ,photos and feedback,congrats to the podiumites.I am happy with 13th as having no time to setup the car i feared the worse

[Aloha]

Allan....great job as you always do. Mr. Smokeio what a great job. J Scott that is a great performance as well. Allan you are entitled to the home track advantage. I found especially interesting the 10 lap average times and how they play out to show car consistency. I was worried about only using a 20K motor so will see how it plays out.
Would love to see what the underside of the chassis look like.
Aloha
Dale

[Austin]

23. / #61 / Porsche 911 RSR / 6.742 / 6.94 / Plenty of power from the long can IL, predictable handling, some chatter

All my cars in all the proxies have tire chatter, Why is this and what do I need to do better ?

[bov]

Hi Allan,

Thanks for the update. Looks like I shouldn't have so diligent in honouring the due date, and spent the time trying to find some speed.....

I could be in trouble compared to the mighty impressive 'Cast of the Fast'... :violin:

[Z-carfan]

Great report, thanks for the rundown.

30. / #31 / Lola Mk 3b / 6.980 / 7.14 / Great brakes, some tire chatter, stays in the slot

Very good input on the car, I’m curious if you think the chatter is due to the finish in the rears? I didn’t get time to do a fine grit sanding. With the brakes maybe she’ll be good on twisty tracks. :text-thankyouyellow:

[BARC 1]

Hi Allan

Were their issues with the #19 Ferrari. Looks like it didn't finish the 10 lap qualifying run.

The guide issues are something that is a problem on all my builds. Got to get this sorted out for the SCCA entry.

[Audi1]

Hi Austin and Z-carfan. I'm not an expert, but, in general, I've found the chatter comes from not matching the truing/finish on the tires with the characteristics (flex/stiffness) of the chassis.

Chatter comes from the tires making and breaking contact with the track; a sort of micro-slippage (traction-no traction-traction, etc.) that's heard by us as chatter. I've found three things that can, under the right situations, help to limit chatter:

1. Truing the tires so that the contact patch on the rears is flat with respect to the horizontal plane of the chassis. All truing is actually "ripping" since you're using some form of abrasive to effect the truing. Courses grit sand paper rips bigger chunks of material off the tires. Finer grit rips small chunks. Having smaller chunks ripped out of your tire; smaller depressions in your tire surface, brings you closer to a flat surface. There are also tire cleaning solvents that tend to smooth out a tire surface; lighter fluid works to do this on rubber tires and isopropyl alcohol works to do this with urethane. Having a flat tire contact patch helps a lot with reducing chatter (this is also true with silicone tires - which are not allowed in this proxy).

2. Radiusing the rear tires (profiling) is also important in reducing chatter. If a tire has a sharp edge, or a non-radiused edge where the contact patch meets the sidewall, then there is no "boundary effect" or buffer layer and when the car starts to roll onto the sidewall in a turn, there's nothing to provide some form of grip transition. As a result of that, the tire looses traction and slips on it's "edge" (again, traction-no traction-traction, etc.), over and over again and that's also heard as chatter. Most all tires; regardless of the compound, will benefit from some type of radiusing and the faster the track, the more radiusing is useful. In producing the radius, you also want the radiused sides to be as smooth as the contact patch of the tire, since you want the same tire surface finish to be presented to the track whether the tire is flat or whether it's tilted and running mainly on the radius.

3. If your tires are well trued and radiused and you still have chatter, then the place to look next is likely the interaction between the rear and the front axles and that is, generally, a function of the pliability of the two; the way that they act together to provide enough overall chassis twist to accommodate changes in track conditions and grip as sensed by the rear and front tires. Podded cars make it easier to see this effect. Now, there are exceptions to every rule and what I'm about to say is, first of all, not a rule, it's just my observation. I find that when I'm running a podded car and the chassis is stiff, if I tighten down the pod at all 4 points (or 3 points; depending on the pod), then I increase tire chatter, because I don't allow any flex; or at least I minimize the flex, between the front and rear tires. As I loosen up the pod screws; as long as I keep a piece of tape across the chassis and pod to help maintain their relative positions, the looser I run them, the less chatter I get. On chassis that are somewhat flexible in the rear, it's become more common, recently, to have the front screws looser and the rear screws tighter; again, factoring in the natural flex that you get with thinner sections of the chassis. This aspect of tuning and reducing chatter is a lot of trial and error. But, in general, a chassis that is set up in such a way that it inhibits good traction "communication" between the front and rear tires and inhibits the ability of the chassis to absorb differences in traction, leads to more chatter.

So, those three places are where I'd start if I were looking to reduce chatter.

I hope that others who have more experience than I do will add their own observations about reducing chatter to this thread. In general, the quieter the car is on the track, the better the traction and the faster the car.

This is also true for the mechanicals of the drivetrain. I have seen very few "whisper quiet" cars that weren't also fast.

Sorry for the threadjack............. :text-threadjacked:

Allan

[Audi1]