Cars-Stars 2019 "Rodd-E-Liminator"

I had made some flywheels for my Cox .049 engines when I had access to a CNC router machine. Their hubs have .125" (1/8")bores.. which is the correct size for the 5-40 machine-screw which fits the Cox .049 engine's crank-shaft.

The largest of the flywheels was made from 1/2" (.500") sheet PVC.. and cut to a diameter of 1.375". Material was removed (hogged-out) from the inside.. to a diameter of 1.125" and a depth of .400".  

This size is the size for my trial drive-wheel..



I obviously needed a traction-element. I am trying some bicycle-tire type "inner-tube" rubber (Butyl-rubber) 26" wheel-size which I hand-cut 1/2" sections of.. to fit the width of my wheel, for "tires".



Then I cut some extra "tires" to experiment with stickier tread-compounds.. in case I had traction-issues.



If I still experience "wheel-spin" with the stickiest 1/2" width tread-compound.. I have the means to increase the traction-surface by 100%

Here's a 2x width version of my wheel/tire which should have been posted here.. rather than creating the "PHATT TYRE" thread..  




This is an assembly of two of my 1.437" diameter flywheels oriented with their flat-sides facing each other. Note that the engines' drive-washer fits inside the inner flywheel. I'm hoping that this will help with balancing.



If the assembly spins out-of-balance.. I can try re-mounting the tire. It fits very tightly on the wheel assembly. The wheels actually have to be assembled-together (mounted to the engine) in order to mount the tire. I doubt that I'll have any issues with the tire coming off due to centrifugal-force.

I'm using a Tee Dee style aluminum spinner for a "hub".. because it works well with my elec. starter.

I LIKE the idea of this double-wide (26mm) direct-drive set-up.. but it might not perform well on rough-pavement. The "tire-material" is thin/butyl-rubber.. which might run really well on a smooth-surface. A stray pebble on the circuit, could cause wheel-spin.. and subsequent model spin-out.





More paint-work/fuel-proofing needs to be done to the car-body, before I can even free-run this little gem.. but the free-run will be fun. I'll try to get a video of that.. I need to test this direct-drive configuration.. to see if the engine will continue to run after a "drop-launch".. or whether it will need a "push-start". The "latter" would require on-board ignition for a glow-engine.. but we can engineer that.. if need-be..

This is supposed to be a tether-car.. but I haven't devised a bridle set-up for it yet.. Other than that, I could try to free-run it...





I'm running oversize (ID) fuel-line using compression-fittings made from alloy tubing. It's an ongoing experiment to assess fuel-delivery from a remote "hard-tank" with only the suction from the engines' venturi.

getback wrote:You have got plenty of hole's there hook it up brother !! I think my pics are on my phone that i can't seem to get since my Son came home !!  Wait //

RUN THAT PUPPY BROTHER!!!!

Cribbs74 wrote:That’s a wild design Roddie. Pretty neat!

Thanks Ron. I need to put a small piece of air-filter material between the engine and firewall. The backplate/carb doesn't have a screen in it.. and it's sure to suck-in some grit if I don't.

akjgardner wrote:Lookin Good Roddie

Thanks much Joe! I've done a little more work to this creation.. over the last few days. There had been two concerns that definitely needed to be addressed. One being an air-filter.. because of the backplate/carb on this engine having had its' screen removed. I had previously made-up a few air-filters which consist of small squares of polyurethane filter material sold for portable (window) air-conditioners.



One square placed between the engine and firewall will help to keep grit from being sucked-in from the drive-wheel.

My second concern.. was similar. The #1 cylinder installed on this engine needed some sort of shield against grit finding its' way into that big/wide-open exhaust-port. I'd thought quite a bit on what to do.. and came up with something simple. It should definitely help. It's a strip of .008" Tin.. that fits between the case and the heatsink. It wraps around the cylinder in the critical-area where the drive-wheel is. A #2 machine-screw and nut fasten it the body above the engine.




She still has no bridle for a tether.. but I've got some ideas. The wide-stationary rear axle is for stability.. in case I want/need to free-run it. I have no idea how this vehicle will track.. with its' direct-drive configuration.

I added a cast acrylic internal hub to the drive-wheel.. because the drive-wheel assembly was pretty lightweight.. at .4oz. Adding the acrylic-hub upped the assembled fly-weight to .6oz.

I had envisioned an adjustable tether, for the last few days/nights.. and came up with this...




I can adjust the toe-in/out on the bridle.. via the spring-collars. I'm not sure if that will be enough to trim this model though. We'll just have to see.

I'm open to suggestions for a tether-line length..

NEW222 wrote:Woah! She is quite the low-rider! By the looks of it, it will either be a very quick car, or if it was me, I would put a wing on it cause it looks like it is ready for take-off... And great job on it!

Chancey.. you're too kind bro! I appreciate the words of praise. I've never built a model-engine-powered land-vehicle.. and this one being my own (unproven) design.. well .. it might stall-out as soon as its' direct-drive wheel hits the pavement. I don't have a back-up plan for that scenario. It's a fairly lightweight vehicle.. so I'm figuring on some "wheel-spin" when I launch it. I've made provisions to add weight to the chassis; in case the traction doesn't "hook-up" after a few laps.

I'm considering a longer tether than originally planned. It will likely be approx. 20 feet long.. for a 40 foot dia. circuit.

I tried running the engine last night.. and the "tire" (a section of bicycle inner-tube..) flew-off the wheel as soon as the engine-revs came on-song..



I captured a video.. but am having trouble getting the file from the camera. My cam has both; "memory-stick" and disc media. The test-run inadvertently got recorded on disc. My laptops' disc-drive doesn't work.. but it doesn't really matter. It's not worth watching.

I want to use this type of tire if possible.. so I need to "bond" the rubber to the wheel. Not sure how I'm going to accomplish that yet..

Marleysky wrote:Roddie, I believe you need to use “rubber cement” to adhere the inner-tube to the wheel. Put the tube on the wheel, roll 1/2 back onto itself, coat both wheel and the tube with glue, wait the required time, then roll the tube back onto the wheel, the roll back the other side and  do the same thing.  Rubber cement or contact cement will stay flexible and keep the tube from flying off the wheel.   My  worth.

Hey Rene! Thank you for this suggestion! Rolling the rubber 1/2 way back on itself is something I didn't think of.. for a no-fuss method of being able to adhere the rubber to the wheel. This gives me a few options now..