Eagle Climax, Al Pease

[Andrew Rowland]

My build is just starting to build momentum as it were....
I am once again putting my faith in the policar gearbox hoping that with free motor choice it's benefits will come to the fore!
I chose this car partly because it seems so Canadian, partly because I like learning about obscurity and partly because the Scaley body is a decent starting point.
I have decided to build everything in the computer and 3d Print. Just for fun and as a counter poise to other cars which will be 100% handbuilt.
I will post photos as I get them out of photobucket...

















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[Andrew Rowland]

Ok, some images of the prototype chassis, mounting in the body, the chassis with the gearbox and the body on its wheels showing the extent of hthe changes required....

[munter]

I always read your build threads, Andi and admire your techniques and construction methods.
One thing I wonder about with printed/plastic chassis is the weight or rather lack of it.
How do these builds run in comparison with a wire/brass chassis car?

Also I am interested in the Al Pease visor bubble...I did start on trying to emulate that myself a while ago but my attempt stalled.

[Andrew Rowland]

Hi John, thanks.
Well the way I see it is that it must be an advantage in terms of engineering to be able to build lighter and then add weight exactly where you want it. If indeed you want it at all.
My experience with the Policar (the Tecno even before the Lotus) is that good handling can come with very light cars. Of course some love the Policar and others find it doesn't work on their track / set up.

As you saw in the VRAA the Policar set up was a distinct disadvantage. I would argue that was at least partially down to the low powered motor not overcoming the extra friction from the gearbox. Who knows. We will see in the autumn!!

My plan with this build has been to build a car which can perform as well as the Lotus 72, using my own fettled car as the benchmark. I've done quite a bit of testing and i'm adrift by about 2 tenths but hope to improve on that over the next month. The track is very similar and I have set the guide in relation to the rear axle to be the same.

For the first time i've decided to invest in a tyre truer and have ordered one today. I can't get the fronts round and the car is therefore considerably better both handling and in terms of lap time without front tyres at all. Also the rears I'm using are too large in diameter so having a truer im expecting to make quite a difference to the performance of my build.......

Yes, the bubble is going to be tricky. I have a dental vac former but the time needed to make a decent mould might be too much. In the race I am emulating he had it very dark tinted so I am considering doing it solid and painting it gloss black.

Cheers
Andi

[munter]

Having a truer of some form is a must especially for a lighter car...the bouncing will be higher without one.
Urethane tires true beautifully on a machine. Just be careful that you dont over do it. It is possible.
I didnt notice your cars performance in the VRAA as the tears I shed over mine blurred my vision.
My bubble visor is sitting waiting for another few hours attention which I do not have available at the moment.

Regards
John

[Andrew Rowland]

John, what do you mean by 'over do it'?

I have had quite a frustrating time truing the fronts which were absolutely oval to find it makes absolutely no difference to performance. I have also trued the rears and again find that if anything the performance is worse!! Have I overdone it as you suggest? The trued tyres don't have the urethane production 'shine' anymore and seem to pick up all the dust off the track? Do I need to somehow polish them up?

Help please from those who know and are prepared to share their secrets....

Cheers
Andi

[Andrew Rowland]

I am sorely tempted to build the driver like this....



I wonder if Stewart would mind?
Andi

[David Mitcham]

Go for it, Andi - but only if you put a working video camera in there.

Best Regards

David

[munter]

Hi Andy, maybe you have over cooked the tires.
Urethanes lose their gloss during the truing process which is logical when you think about it but the surface can be sanded and polished with finer grit materials or 500 laps of your track.

I use my truer(hudy)on 5 volts and take things slowly through the process. If you apply too much pressure, too much speed or have the tire incorrectly seated then the results will be less than desirable.

My only suggestion is to try again with another set of tires.

[Andrew Rowland]

Thanks, will try again as you suggest.

[old23]

As suggested, slow and steady is the best approach to truing urethanes. However, as shocking as it may appear, after more than a dozen years of doing this I still do not own a Hudy or similar "tire truer". I use an old Ninco chassis, one that I can get a good grasp of, equipped with a Slot.it rear end (bushings, axle and crown gear) and a torquey Boxer motor. I fasten the pair of wheels/tires to be trued to the axle and gently lower it to a sheet of sandpaper on a test block with a variable power supply. I start with rough grit paper (75-100). When I get close to the desired tire diameter, I switch to something like 200 grit and then finally polish the tires with some fine 600 grit paper. Throughout the process I frequently pause to check with digital calipers that the left and right tires are of equal diameter and adjust the balance of my pressure on the paper to correct any discrepancy.

Not very scientific, I grant you, but I have managed to win a few proxies over the years.

On the other hand, I've also lost a few dozen proxies in my time. How many were due to ill-prepared tires I'll never know.

And Andi, if you want to build the Pease Camera helmet, be my guest, but good luck finding any 0.5mm film stock to load it!

Stewart

[chrisguyw]

Jun 13, 2017 1:30:07 GMT -5 Andrew Rowland said:

I have had quite a frustrating time truing the fronts which were absolutely oval to find it makes absolutely no difference to performance. I have also trued the rears and again find that if anything the performance is worse!! Have I overdone it as you suggest? The trued tyres don't have the urethane production 'shine' anymore and seem to pick up all the dust off the track? Do I need to somehow polish them up?

Help please from those who know and are prepared to share their secrets....

Cheers
Andi

Hello Andi, A couple of tips/hints/suggestions if I may.

1/ If you have trued the fronts (which as you say were "oval"), and have not noticed any performance difference, I can only conclude that your front tyres are not running on/touching the track. For these cars ( light, relatively narrow rear track, comparatively hard tyres) it is critical that both front tyres touch the track.......they will act as "outriggers" that will support the car in the bends, and add considerable stability. So you may want to recheck the front end set up...........if the front tyres do touch, you will absolutely notice a considerable difference with "round" tyres.

2/ If you have trued your rear tyres using only the drum on the Hudy, it is perfectly normal that they will not grip as well as those with a "production shine". The "tooth" that the Hudy drum leaves on the tyre will very slightly reduce the contact area of the tyre, (it will run on the tops of the teeth), and, more critically, this "tooth" will grab bits of rubbish/dust much more readily that a "smooth" surface.
So.............to regain this lost grip/performance, you must polish the tyres........(you won't get the shine back, but, you are looking for a smooth even surface)......back on to the Hudy, and wet sand starting with an 800 grit or so paper, progressing up to 1500/2000. When you change grits, give the tyres a quick wipe/rub with some Isopropyl alcohol, and another couple of "iso" cleanings when you are done.

Cheers
Chris Walker

[Andrew Rowland]

Thanks everyone for your feedback. What I think is terrific is that people on this forum (and this little 'world' of ours) are prepared to share these kind of tips despite the risk of creating harder competition...l a bit like the sort of gentlemanly behaviour which existed (to a degree at least) when they raced the real cars.....

Anyway to the points raised:
I think I have indeed cooked the rears so have two sets on order form Paul Gage. The postage is equal to the tyres themselves but that is life....
I had not realised I needed the Hudy to be at less than 12v so thanks for that tip guys. It was quite aggressive.....
I will polish the tyres using 600 and 2500 grit. Not exactly what was suggested but it is what I have and hope it approximates reasonably well!
The front tyres do touch the track (just). Before I trued them they touched for most of their circumference..... but the car was obviously going up and down on each side as the wheels turned. The fact is I have my car set up with body rock and the pod loose so while this will affect the overall stability it might not be affecting the overall performance as much as for a solid based car.

Unfortunately the cooking of the rears was simultaeous with the rounding of the fronts so while I may have gained on the front I must have got an almost exact matching loss on the rear.......

Again thanks
Andi

[Andrew Rowland]

I've been designing and printing my own decals.



Cheers
Andi

[Andrew Rowland]

The build is coming together! I got the printed engine and gearbox detail through yesterday and it is now starting to look like a car. More or less it all fits which is a relief and so a bit of tweaking and I should be able to glue it up and start some painting.
Of course the print needs a little bit of fettling to make sure everything fits and a little bit of finishing to make sure the swarf from the process is cut and sanded off but all in all I think it is going to look and work ok.







Cheers
Andi