Cars-Stars 2019 "Rodd-E-Liminator"

Marleysky wrote:

Roddie, keep an eyeout for that barbell weight, but also keep a watchful eye out for discarded floor lamps. They usually have a heavy weight in the base, and the upright pole just threads off, and they have a electric insulated tube for the lamp wire which can be made to hold the thether string or wire on a washer and nut.

Another great tip Rene.. Thank you! You and I should brainstorm together on a Cox engine powered "Pod-Racer"..

CEF member Marleysky (Rene) offered an idea for anchoring the tire onto the wheel that I'm using on the Rodd-E-Liminator.. While I "do" have contact-cement somewhere.. I chose to try adhering the Butyl-rubber tire to the PVC wheel using some double-sided "film-tape" from my old remnant sign-shop stock. Rene's "method" for its' application however; was adopted..





One half of the wheel-width set-up..




I needed to re-paint the wheel after all the poking/prodding.. and tonight; I decided to add a 2nd tire-wrap.. although without any type of adhesive. The 2nd tire-wrap seemed very tight; when stretched-over the first. We shall see if it blows-off when the engine comes alive. The tires are made from Butyl-rubber "bicycle-tire inner-tube sections" from 26" tubes. I'd like to source a 27" inner-tube.. because it would be a smaller diameter.. and hence; a tighter-fit on my wheel...

Thanks for that advice Frizzen. That would be a "new-to-me" type of CA.. I'll keep an eye out for it.

Mark Diedrichs wrote:Mr. Roddie, I think you are very innovative. Just putting this out here...This stuff called Walthers Goo, Might help. Once it sticks it sticks. Works great for me! All the best, Mark

Hey Mark D.!! Thanks for the suggestion. I don't know if what I've done (the TESA double-sided film-tape) will work to keep the rubber on the wheel. I haven't had time to bench-run the engine, since that change was made.

I don't even know how much time I have to get this model running for a video. I'm thinking on setting-up a short tether-circuit in my driveway. That would be an 8-9ft. tether.. for a 16-18ft. diameter circle. My driveway is relatively smooth.. and it would save me from having to set-up at a remote-location.

I've been thinking on some designs which would provide the most accurate data.

I'd been thinking about how-to build a tether-post for this model. The model weighs 5.6oz. I decided on a 5gal. pail weighted with dirt/gravel. A snap-on pail-lid is center-drilled for a 1" dia. wooden dowel-post. The post has provisions for both; anchoring it in the pail.. and also to contain the tether from slipping-off the top.

Here's a preliminary-photo..



The pail is out in the driveway.. (one that had a tomato-plant in it last Summer..) My plan is to use some old .018" stranded SS control-line for the tether.

Oldenginerod wrote:

For what it's worth Roddie,    I'd suggest something different from what you're proposing. The tether connection is way too high and as centrifugal force increases it will cause the car to lift, making it lose drive.  The closer to the ground the tether is the better.  Because your car is so light it won't take much to break traction.  The best scenario would be to have the pivot point lower than your bridle, causing downforce to increase as centrifugal force increases, although in your configuration that's not possible.  You may need to add ballast to your car.

Hey Rod, Yea.. I didn't think about that.. but you're right. I'm hoping to run the car today. I suppose I could use a hardened masonry-nail with a small fender-washer driven into the asphalt. That would be as close to ground-zero as I could get.

Here's some other photos that I shot this morning for the contest.





I didn't take any from the outboard-side.. because there's not a lot to see..

maybe there's still time????






I'm using two crimp-ferrules for added safety.. (both ends of the tether)



Gardening "and" tether-car set-up..







Getting the "pit" ready.. 6:16 pm EST..

CEF C.A.T.S. contest-night (cont.)






I'd forgotten; with less resistance on the crankshaft.. the mixture needs to be leaned-out substantially. Only after closing the needle (almost fully..) the engine started to pop..

I had x2 layers of tire (inner-tube) on my drive-wheel. The 1st layer was adhered using double-sided film-tape.. and the 2nd layer was just wrapped-over the 1st. When I "cold-started" the engine.. the 2nd layer "blew-off" (out of sight..  ) but the 1st layer stayed-put.

The first "tether-run" showed promise. The engine was screaming.. I pulled the glow-clip off and let the car go. It took-off like a shot..  and completed  x1 lap (12 foot tether) before I could move the the support-gear out of the way. The outboard wheel snagged the electric starter wire.. and fouled the run.



That incident "yanked" the bridle hard-enough to pull one leg out of its' 1/64" ply disc-retainer.



I made a field-repair.. but the second tether-run "ate" the tire.. and stalled the engine.





I should have applied "Marlysky's" (Rene) advice on adhering the rubber to the wheel using rubber-cement..

Hey gang. The C.A.T.S. contest has been a lot of fun! I never thought that I would have ever tried designing/building a wheel-driven/Cox engine-powered land-vehicle. I had my doubts as to whether a "direct-drive" would even work..

Well.. even if I'm tearing the rubber off-of the drive-wheel..  .. the current-configuration seems to hold promise.

Earlier this evening.. I set-up to mount "two new layers" of rubber onto my 1"w. PVC wheel. I'm using the TESA-brand "film-tape" to mount the inner-tube rubber again.. because I believe that it will hold-up. I used rubbing-alcohol to keep all of the mounting surfaces squeaky-clean.. for the best adhesion possible.





My car only completed x1 lap before becoming entangled in my electric-starter wire. It was that-fast.. that I didn't have time after releasing the car; to move the support-gear back out of the way. The cars' tether-bridle was also ripped-out as a result..  

Being a "direct-drive" design.. this tether-car may not achieve a 1:1 traction-coefficient during its' run. The tether is 12 ft. long (24' diameter circuit) and the cars' weight is 5.5oz. The direct-drive wheel might burn the rubber right-off the wheel.. but I plan to run the car again tomorrow (Saturday)

Tonight I'm going to do a little work to "sure-up" the bridle. Once that's secure.. the car should be ready to run.

Cribbs74 wrote:It started out well. Always keep kit boxes away from the circle!

Looking forward to a video.

Oh yea.. I know that all too well now.. SoOo.. I re-worked the bridle-mount tonight. I had originally fashioned a pair of  1/64" ply discs (3/4" diameter) center-drilled for the 1/16" music-wire. Retaining them with only "spring-collar"s was foolhardy. The first run which fouled on support-gear proved that.



I tried bushing the thin ply-discs with plastic flat-washers.. but the drive-tire was too far gone for another run.



Tonight I replaced the 3/4" diameter plywood discs with plastic ones.. and reinstalled the smaller 1/4" dia. plastic flat-washers over them, for safety.




I then re-mounted the drive-wheel. Tomorrow I will set-up some video-cameras and try to capture a run, from more than one angle.

The car should be ready to run.

getback wrote:Shoot man i was just Happy to see you out there having FUN !! Looked like it was going to haul some butt and take NO passengers Bee watching for the next run !!

Ha! .. those two vids were shot via the "dash-cam" in my Trailblazer, which I always back into the driveway. The trouble is; I'd never tried uploading files from that cam to Youtube. The audio is in sync.. but the video frames are too fast. (I don't actually walk that way...  ) The vids play correctly through the player on my laptop.

I'll use the Sony camcorder for the next trials.. and maybe ask Lynne to capture some vid with her android phone.

aspeed wrote:Is the bridle supposed to be at or slightly behind the C of G like a plane, or does that not matter?  I am wondering for mine too... some day.  I tried getting it to run last week but ... lots of luck, all of it bad.

Hello aspeed. I'm not sure where the optimal position should be.. and I haven't ran the car enough to experiment. What sort of trouble are you having?

My bridle-design permits toe-in/out via the spring-collars if necessary.. but I would assume the best position would place the car perpendicular to the tether.

I actually (just now) checked the lengths of the front/rear bridle-legs (toe angle) and found the front to be slightly longer than the rear. I adjusted the front spring-collar to equalize the lengths. This should theoretically position the car perpendicular to the tether.