Gravity Racer, take III

Doug S.

The protoplasm may be 70, but the spirit is 32!
Lifetime Supporter
Waiting with ‘bated breath for your race results. You should be a shoe-in with speeds like you achieved in your test runs.
I’d say “break a leg...”, but that’s another event, altogether.
Wishing you a safe and rapid descent to the finish line!!!
CHEERS!!!...from Doug
 

Chris Kouba

Supporter
So... get out the brooms, we swept the podium:


L to R: 3rd place - Andreas Gute in the Mk V, 1st place - me in the Mk VII, 2nd place - Alyssa Hanson in the Mk I

What a day! Most everything went right to plan until it didn't... From slowest of our entries to the fastest:

The Mk III - Never planned to be an overall contender but more of an enjoyment ride down the hill, this was piloted by Sean Doran who got connected with the team as part of a fundraiser for a local school. The bodywork was themed and painted by the third grade class of the school and he went out testing and karting with the team for a number of sessions prior to the big day on the hill. The car was running in the mid- to high 30's in testing and topped out in the low 30's on race day (the race course isn't quite as steep as our test hill), and qualified with an average ET of 104.7 seconds. Car ran well down the mountain and Sean was very happy with his entire experience on the team. He was truly a competitive spirit (see below), a great fit with the whole group and a pleasure to have represent the Scuderia.



The Mk VI - This was a new build for this year, designed by Jeff Burns for his wife (and last year's 3rd place winner), Jenny, to drive with Alyssa and Jodi down the hill. Based on its size, we knew going in that it would be a challenge to get this car through to the final heat- it would have the mass to overcome the drag, but it might just have a little too much drag to overcome. Regardless, it was a beautiful and well constructed entry, complete with disc brakes on the BMX wheels which I had the pleasure of precision machining and welding (no pressure, right?). It also sported fantastically constructed aluminum fenders which Jeff beat into shape himself. On race day, Jenny qualified 13th with an average pass of 88.6 seconds but was knocked out of the fight in the first round of the finals.

The Mk VI in the staging lanes:

Jenny behind the wheel, Alyssa riding shotgun, Jodi backseat driving

The Mk V (2018 winner) - Dusted off and re-entered (you know, because we could...), this car was basically right off the podium from last year's event. It made ~half a dozen testing passes one day in June for the driver line up to get familiar with the car, then it went back on the stands until getting loaded up for the event yesterday. Really the only thing we did to it was replace the tube which tore its valve stem when we were checking tire pressures. That's it. This year it was capably piloted by friend and supporter of the team, Andreas Gute, who was dumb enough to think that snuggling into 170 pounds of steel, plastic, rubber, and duct tape to run downhill over 45 mph was a good idea. He qualified the car #2 with a 76.2 second average pass and won his two prelim rounds to make it to the final.

The Mk V on course at speed:


The Mk I (2017 winner, 2018 3rd) - This was a substitute entry for the Mk II but was also pretty much as-raced and off the podium from last year. It went to testing this year strictly as entertainment for the other drivers who were sharing rides just to make passes and get seat time, not for race development and was literally a last minute car swap. Last Thurs, I made my first pass in the car since 2017 (before we had decided to make the swap, purely for nostalgic reasons) and when I stepped out of it, I was still blown away by how sweet and forgiving the car is. It just had no bad habits. A few things aligned to make running it the right thing to do, and the driving duties would be shared by the whole crew of drivers- Jenny, Alyssa, Jeff (formerly Chief Mechanic), and Sean. On race day, most everything went to plan, until it didn't during Sean's heat in qualifying. When trying to overtake someone with a reputation for foul play, Sean made a move around the outside and they drifted out into him. He kept it on the road but sustained some wheel skirt damage in the skirmish. The nemesis didn't fare as well, having a handful of his spokes broken and a tire which went flat by the finish line. Upon return to the pits we had some work to do, but nothing insurmountable. Sean was ripped though and primed for a grudge match, which proved unnecessary due to how we were already qualified 1-2-3, with the Mk I averaging a 75.9 second pass.

The Mk I wrapping up the semi-final run, Jeff behind the wheel and with right front wheel skirt damage/repair visible:


More details to follow because I am apparently over 10000 characters in this post. Stay tuned!
 

Chris Kouba

Supporter
The Mk VII (this year's winner, new build for 2019) - I burned the midnight oil on this car this year. We were a bit behind our preferred development schedule and I wasn't completely happy with how it was shaking down. Tues-Weds this week, I completely rebuilt the front end, trued and balanced the wheels, realigned everything, plus performed some other magic. After being burned last year making last minute changes, I gathered the team for one more session and made some passes. All the work paid off in smoothness and quietness, but it wasn't until the testing data started coming back in that I had any confidence that the new car was any faster than last year's- it showed we were making passes which were consistently just slightly faster than last year (~1-2 mph). I hadn't completely mentally committed to driving the new car (but knew I needed to) so I was glad when the data started playing out.

The Mk VII staging for its first heat of the day:



On race day, qualifying went reasonably well, until it didn't...

First pass was a respectable 72.3 seconds, with the car handling exceptionally well. I was worried about it being able to handle the lateral g's (we have recorded >1g laterally) and I was really wanting to push hard this year. Seeing as I hadn't even broken into the 71's, I tried to carry more speed on my second pass. As a result, I took a tighter line onto the finish straight and had a massive moment bucking over a manhole cover/asphalt patch. I went lock to lock saving it and quite honestly am not sure exactly how I did... but I did, and I also managed to still pull down a 72.8 second pass.

But wait, it's not over yet... Qualy pass 3 will never be forgotten. There is another one of those manhole covers just past the turn in to the "Learning Curve" (big tight right-hand decreasing radius sweeper near the bottom of the course). Yes, I knew about it and I'm not sure how it happened, but I set up wide, like I should, but didn't turn in quickly enough, and at least one wheel ran over the cover and completely upset the car. The tail started coming left around the front and I went full opposite lock, steering into it with all I had. I was able to save it enough to only drag the right front through the inside (right side) gutter and get re-launched across the track to the left, with the tail end actually coming around on the right side, leaving me pointed back uphill but still rolling downhill- just facing backward at this point (~.2m from the finish line).

Everyone scoffs at rules, right? I give every effort to comply with them as when/if I win, I don't want it to be because we cheated or did something sneaky. We built the cars in total compliance with the very reasonable rules. Well, part of the rules of this event includes we need functional horns and mirrors. In the moment, this actually left me an option: turn the car around with a 934-point u-turn, or use my fully functional mirrors to simply coast backwards the last stretch to the finish. Guess what I did? That's right, brought it home in reverse, using 3" convex mirrors. I really hope footage surfaces on facebook or youtube. I'd love to see it!

Also, I still won the heat!

It wasn't without cost though. I had plowed a pylon in the gutter mid-spin and crushed the right side axle airfoil and knocked the right wheel pant out of alignment as well. Thankfully we had time in hand to repair it with a teardown and reconstruction in the pits before the finals started.

So we qualified 1-2-3 and swept the prelim's and semi's. Now it's the payoff round!

Staging for the final round:


I lined up on the inside lane, Andreas in the middle, and Alyssa on the outside. We all got off to decent starts but I think Alyssa and I had a small edge over Andreas. I slipped marginally ahead into the first left hand corner, only putting about half a car length on Alyssa. Moving into the right corner, she clawed back the distance and put me about even with her cockpit. As we moved into the next left hand sweeper and picked up speed, I was able to close that distance back up and as we continued to gain speed, I was able to slowly walk away from her down the main straight. After my prior experience, I was able to appropriately manage my line through the big corner and finish straight to cross the line first, with fast time of the day- 71.9 seconds. Alyssa held on to second with a time of 76.6 seconds, and Andreas pulled a 79.0 second pass. Turns out when Alyssa and I closed up, we pinched Andreas a bit and he tapped his brakes.

The race as seen from the #3 car (third place):


And the finish from outside the cars:


The podium:


I'll have more pics to post in time, I had little time to take them myself and they are only now just trickling in over the internet.

What a fleet:
 
Last edited:

Alan Lofurno

GT40s Supporter
The Mk VII (this year's winner, new build for 2019) - I burned the midnight oil on this car this year. We were a bit behind our preferred development schedule and I wasn't completely happy with how it was shaking down. Tues-Weds this week, I completely rebuilt the front end, trued and balanced the wheels, realigned everything, plus performed some other magic. After being burned last year making last minute changes, I gathered the team for one more session and made some passes. All the work paid off in smoothness and quietness, but it wasn't until the testing data started coming back in that I had any confidence that the new car was any faster than last year's- it showed we were making passes which were consistently just slightly faster than last year (~1-2 mph). I hadn't completely mentally committed to driving the new car (but knew I needed to) so I was glad when the data started playing out.

The Mk VII staging for its first heat of the day:



On race day, qualifying went reasonably well, until it didn't...

First pass was a respectable 72.3 seconds, with the car handling exceptionally well. I was worried about it being able to handle the lateral g's (we have recorded >1g laterally) and I was really wanting to push hard this year. Seeing as I hadn't even broken into the 71's, I tried to carry more speed on my second pass. As a result, I took a tighter line onto the finish straight and had a massive moment bucking over a manhole cover/asphalt patch. I went lock to lock saving it and quite honestly am not sure exactly how I did... but I did, and I also managed to still pull down a 72.8 second pass.

But wait, it's not over yet... Qualy pass 3 will never be forgotten. There is another one of those manhole covers just past the turn in to the "Learning Curve" (big tight right-hand decreasing radius sweeper near the bottom of the course). Yes, I knew about it and I'm not sure how it happened, but I set up wide, like I should, but didn't turn in quickly enough, and at least one wheel ran over the cover and completely upset the car. The tail started coming left around the front and I went full opposite lock, steering into it with all I had. I was able to save it enough to only drag the right front through the inside (right side) gutter and get re-launched across the track to the left, with the tail end actually coming around on the right side, leaving me pointed back uphill but still rolling downhill- just facing backward at this point (~.2m from the finish line).

Everyone scoffs at rules, right? I give every effort to comply with them as when/if I win, I don't want it to be because we cheated or did something sneaky. We built the cars in total compliance with the very reasonable rules. Well, part of the rules of this event includes we need functional horns and mirrors. In the moment, this actually left me an option: turn the car around with a 934-point u-turn, or use my fully functional mirrors to simply coast backwards the last stretch to the finish. Guess what I did? That's right, brought it home in reverse, using 3" convex mirrors. I really hope footage surfaces on facebook or youtube. I'd love to see it!

Also, I still won the heat!

It wasn't without cost though. I had plowed a pylon in the gutter mid-spin and crushed the right side axle airfoil and knocked the right wheel pant out of alignment as well. Thankfully we time in hand to repair it with a teardown and reconstruction in the pits before the finals started.

So we qualified 1-2-3 and swept the prelim's and semi's. Now it's the payoff round!

Staging for the final round:


I lined up on the inside lane, Andreas in the middle, and Alyssa on the outside. We all got off to decent starts but I think Alyssa and I had a small edge over Andreas. I slipped marginally ahead into the first left hand corner, only putting about half a car length on Alyssa. Moving into the right corner, she clawed back the distance and put me about even with her cockpit. As we moved into the next left hand sweeper and picked up speed, I was able to close that distance back up and as we continued to gain speed, I was able to slowly walk away from her down the main straight. After my prior experience, I was able to appropriately manage my line through the big corner and finish straight to cross the line first, with fast time of the day- 71.9 seconds. Alyssa held on to second with a time of 76.6 seconds, and Andreas pulled a 79.0 second pass. Turns out when Alyssa and I closed up, we pinched Andreas a bit and he tapped his brakes.

The finish:


The podium:


I'll have more pics to post in time, I had little time to take them myself and they are only now just trickling in over the internet.

What a fleet:
Crossed the finish line backwards.... just like Talledega nights!
 

Ian Anderson

Lifetime Supporter
Supporter
Brilliant result and well done on all the design and fabrication

Will it be 4 times winner next year?
 

Doug S.

The protoplasm may be 70, but the spirit is 32!
Lifetime Supporter
The third place car had a camera on the roof and got some good video:


FUN RACE!!!
WOW!!! Great video, Chris! Team Kouba ROCKS!!!!!

just curious what kind of brakes you use....if you used bicycle wheels and tires, perhaps you took advantage of the proliferation of hydraulic disc brakes that are appearing on all sorts of bicycles...my mountain bike has hydraulic discs and they are absolutely "...the bee's knees!"

This reminds me of a failed attempt at "Soapbox" style racing...the rules said "NO lubricants" on the wheels and axles. My dad insisted on using graphite and I thought that was cheating, so I withdrew from the races.

I missed a lot of fun, your great video proves that!

Cheers from Doug.....what a great thread!.....and I'm sure the races must have been exhilarating!

GO TEAM KOUBA...looks like you're well on the way to establishing a "dynasty" :cool:
 

Chris Kouba

Supporter
Thanks guys, it is a blast and yes- we have pushed the boundaries of what is possible. I love it!

As for the brakes, they are... woefully inadequate. They are simple rim brakes from a BMX bike used with the best shoes we could find. They are still horrible. The reason we haven't stepped up to discs is twofold- budget and budget. We are allowed $500 to spend on the car. Decent hydraulic discs would cost a bit with custom length lines and such. Second, we have empirically arrived at 20" wheel being "best" and there aren't many 20" disc wheels we can find which don't blow our budget. So yeah, it's a $'s thing- would LOVE to have them.

We got around that on the Mk I and II with mountain bike wheels with disc hubs and I machined a rotor adapter for a 1 liter sport bike (looks KILLER!). That brake, even on just the rear axle, works great. On the Mk VI I machined up some more parts and welded a disc flange onto the wheel hub. That was a challenge, but FUN.

It's too bad you missed on the fun as a kid. I never did scouts or anything but would get super jealous when I saw stuff like that. Never did I think I'd be this into it as a "kid-ult". I do know exactly what you mean about the cheating thing. I didn't want a Mark Maguire asterisk by my name in the record books, so I worked my ass off to make sure that we did everything by the book. We are legit!
 
Last edited:

Randy V

Admin
Lifetime Supporter
Simply amazing!!!!
Congratulations to you and your team on such great accomplishments!!!

Is there a link to the rules for this? I wonder if they have these competitions anywhere near me?
 

Chris Kouba

Supporter
It's all buried in this link:


And specifically the rules are here:


There are other events around the country but the rules tend to vary quite a bit- max dimensions, weight, required # of wheels, etc... I haven't found another event which has the type of course we do though. It appears to be a rather unique event.

You've got the RV, Randy. Get to building and drag it out for a visit. You won't regret it!
 

Chris Kouba

Supporter
The event's official photographer posted his pics for this year:


Some pretty nice ones in there and they certainly give a feel for the whole circus. The tooth fairy car won crowd favorite, best art car, and one other award as well. The guy was suspended by a big piece of surgical tubing while the car ran down the mountain. CRAZY!!

 
Top