Vids of Wall MkII Cubmobile (steering demo)

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Teeeman
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Vids of Wall MkII Cubmobile (steering demo)

Post by Teeeman » Sun Apr 09, 2006 5:40 pm

Here are post-race vids of our CMB that steers, demo'ing the steering.

More vids later...
(the t-bar push/rollbar is removed in these videos, we were just playing around in the street)

http://media.putfile.com/2006-CMB-Left-turn-demo

http://media.putfile.com/2006-CMB-Turn-demo-right


-Terry

Edit: I forgot to mention, we won 1st in speed, by a large margin I think, but that was based on visual observation (myself and one other fellow)... the recorded times showed 3 cars WAY faster (like 2 seconds faster) but the car that was supposedly fastest ... I raced it myself post-race with our Pack leader on the other car... just see the video for the outcome, and I was dragging the brake (laughing!).\
The timing was done with a stopwatch, and while at the finish line post-run of a car, I overheard "hey, what was the time?... I dunno, I missed this one...! .... 12.81s!!!!... yeah, just make something up ... "
(laughing!... but they gave out a ton of trophies, with no entry fee, so I can't complain too heavily)

We also got 3rd for looks, but I felt we should NOT have gotten a looks award... a "cool design" award or something, but NOT a looks award... we did accept the trophy though...


http://media.putfile.com/2006-CMB-Wheel-Failure-Event


Incidentally, we broake a Commtech wheel on this run (with my 240lbs on the CMB)... but the wheel that broke was on the least-loaded side (the side I was not on, the weight box was empty for my run)...

here's a vid of the broken wheel (after we moved it to the front).

http://media.putfile.com/CMB-Failed-Wheel-2006


and yes, I know my kid was barefoot, no gloves, no helmet, no safety glasses, no bulletproof vest, no force-field generator, etc. when we shot the vid of him doing turns in our circle... he had proper equip on raceday though.


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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by sporty » Sun Apr 09, 2006 6:22 pm

Wow the wheel broke,

Holly cow.

And those are used for wheel chairs.

I wonder if it was a bad mold or something.

I watched the videos, pretty neat.

We enjoyed the nice weather this weekend buy working on ours and the kids riding there bikes and play on there modded power wheels.

Sporty



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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by Teeeman » Mon Apr 10, 2006 10:05 am

Commtech is concerned, we have produced their first "in field" failure.

I have to say we heavily shock-loaded the wheel, but I was very surprised it broke.

Commtech is going to replace our wheels, and I will promptly return the wheels we have for analysis.

Commtech is great to work with, and we love their wheels!

(we didn't even degrease and WD-40 the wheel bearings and still handily won the event Saturday)

We'll keep durability a forefront until we lose a race... then it is flush and spray the bearing time (grinning!).

But for now, we have used the wheels exactly as they came out of the box.

We still have a lot to do between now and our Pack race in 2 weeks... going to make the steering easier, replace the front axle with non-treated wood (the current axle has a crack developing, think it happened y-day in the street when I let the car roll, no rider, into the curb by accident)... and still want to implement the car seatbelt and pad the seat.

-Terry


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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by sporty » Mon Apr 10, 2006 10:15 am

Commtech is a very nice group of people.

It's great to ehre they are not only gonna replace the one but all four and do some testing on it.

I also want to add a mention, that the push cubmobile event is different from the hill and ramp race.

But I am also curious, you mentioned you racing it, once. How was that done ? with out a push person ? ramp ? hill ?

Sporty



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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by sporty » Mon Apr 10, 2006 10:34 am

Okay,

I went back and watched the video some more. I answered my own question.

It was a ramp. I noticed the right front wheel was off the ground.

Was that event a cubmobile event ? and 1 more to go to ?

sporty



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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by Teeeman » Mon Apr 10, 2006 12:12 pm

Commtech (Mr. Lemmon) and I talked this morning.

After talking with him about the wheel failure, and what I can remember of the run, it would appear we side-loaded the wheel with a hard impact.

The wheels aren't designed for massive side-loads (though they will take quite a bit!)... on a wheel chair, the wheels are mounted in a freely spinning caster, and side-loads simply rotate the wheel to the direction of travel and it is nearly impossible (I would think) to generate anything near the kind of side-load we did with the Cubmobile.

Just good FYI, the Commtech wheels are still a great product, and I think the failure was due to running the wheel off the edge of the ramp near the bottom.

-Terry


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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by Teeeman » Mon Apr 10, 2006 12:21 pm

sporty wrote:Okay,

I went back and watched the video some more. I answered my own question.

It was a ramp. I noticed the right front wheel was off the ground.

Was that event a cubmobile event ? and 1 more to go to ?

sporty
This was the Cubmobile District, the host (Home Depot, thanks again!) was unable to stick to the original schedule date and we had a late notification calendar bump of 5 weeks (hence we had no paint, geez, I was shooting screws in the garage at 11p.m. Friday evening while the tornado sirens were sounding for the confirmed twister 5 miles from our house, hahahah!).

We used a ramp that Home Depot constructs yearly, then tears down post-race and gives the wood away.

Army volunteers staff the event, the starting system is the volunteers simply hand-releasing the cars, and Army volunteers with stop-watches at the finish line constitute the timing system.

Our car has the right front wheel off the ground by design (PWD trickery at work) with a heavily rearward CG.

Even without flushing the bearings on our Commtech wheels, we were (I believe) the fastest car there by a reasonable margin.

I went bananas and added true steering because this car will get a lot of miles this summer in our neighborhood tooling around when we walk in the evenings usually. The weight box will become a cargo box for my son's assortment of "carry with me" toys he sometimes drags with him to playgrounds (shovels, hot wheels, etc.)


Our Pack will have their first and own CMB race in 2 weeks, at a church parking lot steep enough no ramp will be required. The original calendar had this race scheduled before the District, however our District doesn't require any sort of pre-registering much less pre-qualifying (no entry fee either)... so this is all in the name of fun and recruiting :)

The Pack race may not even be timed, and multiple runs (not just 1 run due to lack of time and huge turnout as was the District race this weekend) will be allowed, and siblings, moms, dads and potential Scout recruits are all hopefully going to get plenty of seat time :)

I'm looking forward to the Pack race with a lot of enthusiasm, wish us luck (I am helping organize it).

-Terry
Last edited by Teeeman on Mon Apr 10, 2006 12:25 pm, edited 1 time in total.


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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by sporty » Mon Apr 10, 2006 12:24 pm

wheels,


I dont see those wheels braking with a child using the cart.

I forget what the weight limit is for those wheels are off the top of my head.

But just watching the video and seeing it on 3 wheels, I noticed that sometimes there was a little jolt, where the weight shifted and caused like a hop on the right rear wheel.

But coming off the ramp, angled and alot of weight put on the wheel. Most certainly would cause a failure if there load limit was exceeded.

I am gonna start a new topic, wheels.

Sporty



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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by Teeeman » Mon Apr 10, 2006 12:29 pm

sporty wrote:wheels,


I dont see those wheels braking with a child using the cart.

I forget what the weight limit is for those wheels are off the top of my head.

But just watching the video and seeing it on 3 wheels, I noticed that sometimes there was a little jolt, where the weight shifted and caused like a hop on the right rear wheel.

But coming off the ramp, angled and alot of weight put on the wheel. Most certainly would cause a failure if there load limit was exceeded.

I am gonna start a new topic, wheels.

Sporty

No doubt we abused the wheel (subjected it to service conditions it was not designed for). The normal wheelchair application (casters) would not have subjected the wheel to the same load we hit it with.

This is not a Commtech failure in design nor testing, it is a mis-application of their design (sorta).

I still think their wheels are my choice now and in the future for CMB design.

-Terry


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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by sporty » Mon Apr 10, 2006 1:21 pm

In a open class, where you can make of the weight loss of the wheel, then they are a good wheel for you and seems you are not running into a spin problem.

Just them what the cubmobile would do with a set of 1960's steel soap box derby wheels.

But then again, price wise, Commtech, you cant beat the great price.

Sporty

I just cant use them, My testing , and times, we cant win with them. But our race is not like yours. Now if they weighed 8 pounds heavier per wheel. I would use them.

But then again, I would want 12 inch.

10 inch rolls faster off the line, but on a 150 foot long track, the 12 inch comes out at the end ahead.

This will be my sons 4th year. He is going to race in 2 cubmobile races this year.

Hes a 10 year old kid, who only weighs, 41 pounds, most 10 year old kids weigh alot more than that.

And since our rules dont allow weight, its a hard obstacle to overcome. But 2nd and 3rd place so far. In a field on average of competing against 12 to 16 riders in his class.

He has never lost buy more than 3 inches and on average about a 1 inch differance, when he looses.

Sporty



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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by Teeeman » Thu Apr 27, 2006 11:27 am

sporty wrote:In a open class, where you can make of the weight loss of the wheel, then they are a good wheel for you and seems you are not running into a spin problem.Sporty

Believe this, our rules are only concerned with the following:

1. wheel must be solid (not pneumatic, for instance)
2. wheel diameter no greater than 11"
3. wheelbase length max of 48"
4. wheelbase width max of 36"
5. overall car length not to exceed 60"

That's it!

Our car still qualifies in the standard run class... even though it is radically different in design.
With no weight limit, we kinda upset one Den leader who had struggled to meet what he thought was an imposed 45lb limit... seeing our car (especially the bricks in the weight box) actually got him a bit defensive when he learned we run in standard class, not unlimited.

Our one car with pneumatic tires that actually belongs in unlimited gets run with the standards, BTW... our event is loosely organized for fun as top priority (even more than safety at times, hahahahah!).... we're working on the safety aspects :)

We still beat the car with pneumatic tires, we have about 100' of race course. I think you are correct in that a larger wheel offers advantage in a longer race... I think the pneumatics also offer an advantage over a great distance (based on a run I saw at our fun run last weekend).

I really want to square off side-side with the pneumatic tired car... I need to track the owners down and issue a quiet challenge :) :) :)

Truthfully, no point in it... it would hurt their feelings, or ours (if we lost!)... either way that is getting psycho over something that is really meant for fun... so I won't.

But I'd still like to know how the cars compare side-side.... even if we did take the trophy from that car 2 years running now.

-Terry


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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by Teeeman » Thu Apr 27, 2006 11:30 am

One last thing, perhaps the single most obvious weak point in the '3 wheel' design (both last year and this year) is when you hit a bump or obstacle, it does tend to cause a torque on the steering slightly and make the car tend to the left...

it isn't bad, but it was there in last year's car and in this year's.

No easy way to overcome it without going back to a 4 wheel design, and the advantages of the 3 wheel for ease of alignment, no steering scrub and saved energy (by not spinning the 4th wheel) make it worth the steering jolt to me.


-Terry


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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by sporty » Thu Apr 27, 2006 11:54 am

Some of the recent videos, provide a nice insight into the ramp.

I actually feel, that it is a pretty nice ramp. The height may be a bit much or its the angle. With out actually being there and checking it out.

On some of the other mentions.

I am not exactly sure how to reply or comment on some of the issues.

It's one of those area's that can be good or bad.

The main goal is for the event to be fun for the kids. then the race was held without lane dividers worries me.

Just to have the event is a plus, Improving upon it after each event is a plus.

The reason from what I can see in the video for the tipping over.

There is a few factors, the angle and height of the ramp, the wheels being to small on them and the steering and no foot safety board.

And overloading with a adult.

In fun, I would enjoy racing our cubmobile against yours, if you were not so far away.

It would be interesting to see how the different set up and styles compared.

About that I can do is what I have done in the past and provide the info to re create the conditions of our event.

3 & 1/2 feet tall, two sheets of 4x8 ply wood (16 feet from the edge of 3.5 feet down to the ground and 150 feet long. on a 99% flat surface (not angled)

the time would be 30.22 seconds to beat. I would already asume you would with your design having more weight to the vehicle.

Or what the other option is, mark off 150 feet (flat and level) and back up to 160 feet and give it a good shove, push for 10 feet and release and see what the time is when you cross 150 feet.


sporty



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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by Teeeman » Fri Apr 28, 2006 12:36 pm

I really wish we (our Pack) had more input to the ramp construction.

I tried for a year to get a 2 way discussion going with the guys who organize the race, they almost never reply to any of my e-mail, I gave up.


Lane dividers, a more shallow ramp, and several other minor things would be major improvements IMO...

our Pack leader this year built and donated a car to the organizing Pack, and it took some very minor damage during the race, he has offered for the guys who have it to bring it back to his house for an evening of CMB repair and burgers/dogs/cokes. So far as I know he hasn't even received an answer... one of his "while we're fixing the car" ideas was to talk some about next year's race.

I've been meaning to ask on a couple of points: Seat sides, I get 100% (hold the kids in the seat).

Footboards: if they are attached to the front axle, the only benefit they offer is to keep a rider from losing their footing and having their foot get unde the car?

If the board is attached to the frame (not the moving axle) then I can see how it might offer some control by the rider planting his heel against it and using just his toes to operate the front axle...

exactly how are they supposed to benefit the rider?

Thanks!





-Terry


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Re: Vids of Wall MkII Cubmobile (steering demo)

Post by sporty » Fri Apr 28, 2006 12:42 pm

Ill send you a private message on some questions to that problem.


The foot safet board, does prevent the riders feet from coming off the steerling block. In the hopes not to get there foot caught or dragged on the ground.

I seen this happen in some of the previous years event. this happens most often just off the ramp.

The jolt or sudden bounce. they get scraped up. Seen a spranged ankle from it and cuts.

Mainly thats why it is there. as for steering aid, I dont think it helps any, but can be used to keep the heel of the sho in a proper placement.

sporty



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