TOPIC:

GingerSpice wrote:

Looking good, the blue makes it look a lot more upto date and yet it still remains a classic.
What's the shell like you will be running on it?

Thanks - I have some non-vintage body shells for it.
A factory finished camo Humvee and a Porsche Cayenne that's still unpainted :





The body posts for the Hummer are fitted but that's all I'll need to change to fit the Cayenne shell.
And with arms and dogbones of different length, I'd be able to fit virtually any 1/10 scale body.
The great advantage of universal on road shock towers.

GingerSpice wrote:

It will be a shame to get dirty but it will be good to see how it handels

Think I don't really have a choice but to drive it. It's looking much too tempting.

Can there be a better introduction to this rebuild report than this vintage poster?



Just a fun item that came in with some other parts - I will put a frame on this one.
There's even some interesting info on it...

Coming up soon...

I've been doing some theoretical calculations to see if the set up for the Manta Ray will be suitable.
First thing is to determine the gear ratio. Of course this is not a set value since the pinion and spur gear can be varied.

It follows this calculation :

Z₁ = # teeth pinion
Z₂ = # teeth spur gear
Z₃ = # teeth idler gear (= 16)
Z₄ = # teeth differential (= 39)

Gear ratio = (Z₂/Z₁) * (Z₄/Z₃) = (Z₂/Z₁) * (39/16) = (Z₂/Z₁) * 2.4375

This translates into the following overview :



I think I will be using a 21T pinion and a 69T spur.
This will make the gear ratio (69/21) * 2.4375 = 8.0

Using an Lrp motor that can do 31000 rpm this gear ratio will give (31000/8) = 3875 rpm on the wheel axle.
This is of course the same rotation speed a the wheel will make.

I am using 30 series Pro-Line tyres which have a diameter of 100mm = 0.1m.
The circumference of this wheel is (pi * diameter) = (3,14 * 0.1) = 0.314m.

Making 3875 rotations a minute, the distance travelled (of the outer edge of the wheel) will be 3875 * 0.314 = 1218m.
Which translates to (1218m/60sec) = 20.3 m/s = 73 km/h.

So this is the theoretical top speed the Manta Ray will have with this set up.

When using a Orion motor (thank you Lars) with 40000 rpm, a 25T pinion and the 66T spur, the car would do 115 km/h.
For the sake of sanity I will stick with a more moderate set up though.

So much for theory - let's build this car!

Been building, fixing and restoring but no so much on the Manta Ray yet - soon!
The wing has been sprayed in the meantime though.

And I've finished some details on the other chassis :



- New GPM modified main drive shaft (replacing the dogbone style Yeah Racing)
- 3Racing titanium turnbuckles fitted
- New set of (slightly shorter) front shocks
- Extra blue alloy king pins ordered for steering assembly

Still on their way are some black ball ends for the steering knuckles and a turnbuckle wrench for fine adjustment.

That is one sweet Chassis, but I am surpriced to see that the drive cups and dobones are not blue

-Lars

Thanks Lars, had to temper the bling a bit - in the end it'll get the camo Humvee body.
Ready for some off road battle but even the camouflage can't hide all the shiny stuff.
Good thing there's even some blue you can't see...

It has some new ball ends in the front knuckles now that are gun metal though!

Hey Edou, quick question regarding the main shaft. I found this one locally:

www.digitalsaon...ts_id=3883

I read your Manta ray rebuild and I think 172mm is the right length. I don't want to buy the wrong one. Is it the right length?

Thanks man.

It will definitely fit the car...
Looks like it's a drive shaft from Yeah Racing btw.



Same one as the one on the pic...

oh sorry, forgot to say it was a Yeah racing part. Cool, then I'll order it. I'll strip the blue off it though.(blue doesn't match the rest of the car)

GPM also has one in silver - but the Yeah Racing is a nice part too.