Scratch build Nitro tethered car

[Roog]

Hey knowledgeable people of RC Talk, I have a question, spurred on by the partial success of my scratch build electric tethered car (thread over on the electric section) and pressure from the club to build a ‘real car’ plus if I don’t build something else the missus will find me something really worthwhile but tedious to do, I am looking to build a car based on an Irvine .20 glow engine which I just happen to have lying about.

The plan is to mount the engine sideways in the chassis.

But having taken a good look at the flywheel/clutch/gearing that came on the engine it doesn’t look like it’s going to be viable to use.

The centre of the drive shaft will clash with the flywheel

Added to this the shaft size in the larger driven gear is only 5mm which is too narrow for the fixed rear axle I normally use which is 10mm dia.

So my question is for me to use my Irvine nitro engine I could do with an alternative flywheel/clutch and drive gears.
The engine drive is via a 1/4”-28 UNF thread I think!

Any ideas of what I could use?

The final drive ratio needs to be around 1:2, slightly less might be OK.

I am open to using gears or belt drive to achieve the gearing.

This time I plan to put a bit more effort into the body shell so that it looks a bit like a 1950’s race car. Out right speed is not the main objective, it just has to look like a car, work and make a lot of noise so that I fit in!

 

[WickedFog]

Maybe @cbaker65 can point you in the right direction?

 

[Doom!]

Wayyyy out of my area of expertise, wait, I think just about everything is out of my area of expertise.

 

[Tunedfrog]

Wayyyy out of my area of expertise, wait, I think just about everything is out of my area of expertise.

Well yeah, but you are adorable so we keep you around.

 

[Roog]

I’ve been looking at alternative flywheels and the ones I’ve found claim to have 5mm threads as opposed to 1/4-28” UNF which I thought was common thread size.

I would like to keep the gear train simple but I am beginning to think that inline plain gears are likely to be a problem because of the space required between engine and wheel drive shafts to clear the body of the engine.

At a push I could justify a new engine and flywheel/clutch mech as the old Irvine needs putting back together each time I use it! :0)

Of course the cleaver old school solution to this is to make a second crank to bolt on the rear of the engine, but that is way past my skill set!

 

[TRAT]

Ohhh tether car!!!!

I got a OG TRAX tether drag car raced in late 50s early 60s. Love them

 

[Weezel]

Why not try running without a rear axle. You could mount the spur gear directly to a wheel. Then I'd use the outside wheel for the most traction.

 

[Roog]

Why not try running without a rear axle. You could mount the spur gear directly to a wheel. Then I'd use the outside wheel for the most traction.

It did cross my mind, but it feels like cheating. :0)

Ohhh tether car!!!!

I got a OG TRAX tether drag car raced in late 50s early 60s. Love them

Interesting, do you have any pictures?

 

[Weezel]

It did cross my mind, but it feels like cheating. :0)

If anything I feel it would actually be harder as only an one wheel drive. Is there guidelines that need to be followed?

I've watched the tether cars go round and round before but never seen under the hood of one. I've even watched control line planes go round and round. Lol. I was fascinated by them when I was a kid.

 

[TRAT]

It did cross my mind, but it feels like cheating. :0)



Interesting, do you have any pictures?

Here is some

 

[J’sCrawler]

Very cool

 

[Roog]

If anything I feel it would actually be harder as only an one wheel drive. Is there guidelines that need to be followed?

I've watched the tether cars go round and round before but never seen under the hood of one. I've even watched control line planes go round and round. Lol. I was fascinated by them when I was a kid.

As a kid model catalogues were full of 'interesting' free flight and control line model plans and kits, they looked interesting to me until I tried it and discovered a world of 'hoping the fuel would run out soon!'

Here is some

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I like that @TRAT the chassis looks nice. Love the chunky rear tires.

Why not try running without a rear axle. You could mount the spur gear directly to a wheel. Then I'd use the outside wheel for the most traction.

There probably are regulations but so far no one in the club seems to be upset with my efforts, I think they are just pleased that they have another member given that the hobby is struggling in the UK.

I agree that having one driven wheel would not be helpful especially as I struggle to get the power down with two. I know one person who added lead weight to their car to get better performance!

 

[Weezel]

I know and understand it's all in having fun with the experience. I was only asking about the "guidelines" as more of a helpful direction in ideas in how you want to design the vehicle.

 

[WickedFog]

Wonder if adding a differential would affect things much

 

[Roog]

I know and understand it's all in having fun with the experience. I was only asking about the "guidelines" as more of a helpful direction in ideas in how you want to design the vehicle.

Of course you are absolutely right, I am terrible at following rules. I expect most challenges have been met before and solved.

Next track day of almost upon us. Must remember to charge my battery

 

[TRAT]

I hate rules!!! As some may know here..

 

[Roog]

Wonder if adding a differential would affect things much

I did wonder this, but I have never seen a tether car with one.
I am guessing but if the inner wheel has less load might it spin?

 

[WickedFog]

I did wonder this, but I have never seen a tether car with one.
I am guessing but if the inner wheel has less load might it spin?

Maybe. You could use a really heavy diff fluid. My guess is it is scrubbing anyway. You'd have to tun the diff to compensate. Would be a fun experiment.

 

[Roog]

Maybe. You could use a really heavy diff fluid. My guess is it is scrubbing anyway. You'd have to tun the diff to compensate. Would be a fun experiment.

Limited slip diff?

 

[WickedFog]

That may be better. Anything to account for the scrub the inside tire is getting. Though it's probably not enough to even worry about.