Hydradrives - why the sudden increase in interest
 

I guess the question is in the title but I'd like to know the advantages from those who have tried them. I seem to remember them going out of fashion post Kinwald's Worlds 97 win as they never were fitted on the XXX series (although I understand you can). Now they seem to be cropping up all over the place. Is this a brushless thing, a mid motor thing or just a 90s throwback?

Cheers

Graeme

Back when they came out you really had to fight to make the batteries last 5 minutes with them on because they increased rotating mass by so much.
With lipo and brushles we now have insane amounts of power, speed and duration, so that hydras have become viable to use again. They really do smooth out a cars throttle response and make bump handling so much better, especially on slippy surfaces. Schumacher used to make a visco-drive back in the day as well, which worked similarly.

they where awesome and yes we need them now for bumpy tracks as power and endurance not a problem so someone make some money:thumbsup:

I found a mint one in my attic when searching through my old racing gear :p

I've got four of the little devils :p

And selling one of them too? :)

I think someone just ran out of double slipper spurs, xD.
Dual pads slippers were faster on 4x2, maybe we should give a try to the Hydra on a 4WD. Anyway, i think i have one somewhere, but don´t know how to try it on a B4.

I've got about 8 hydra drives in my garage.

Couldn't believe a gearbox and hydra drive for a XX went for £55+ the other night.

Funny people mention it as I've been looking at fitting the hydra drive to my XXCR which will be running brushless again this year.

I prefered the Viscous Drive from Schumacher, no need for weird oils, just shock oil, and it was adjustable.

I've got a few rebuild kits, so I may have to get one up and running.

What 3rd party oil do people use with them?

I only ran the standard slipper on my XXCR last summer and I'm not running the XXCR at the moment. During the summer it's a high grip bumpy track.

if I remember there were different thickness of oils, which oils did people run with modified motors?

Exactly what I was going to ask. You'd need and oil with good shear properties. A heavy silicone oil would be worth trying - don't know what weight or viscosity though.

Maybe this 1000 centistoke diff oil would be worth testing?

http://www.losipartshouse.com/servle...-1000CS/Detail

If memory serves correctly, the "buggy" version came with the middle weight oil (medium), trucks came with the heaviest and there was an optional 'light' oil aimed at buggies rather than truck.

Bugger as I have heavy and light :(

may be heavey is the way to go mike??now we have brushless and lipo

from what i could find, the hyrda drive costs about £80 to build up from parts. I cant find any new, so to see them go on ebay for £55 isnt really suprising to be honest.

Indeeed, I did think this as I was running a 7.5 last year with trakpower 3600s

Not Silicone oil then.....

G

Silicone oil has relatively good shear break-down properties.

Not when you get to high viscosities.....

G

Any recommendations on oils and viscosities to try?

When I used to calibrate viscometers we used a different oil for the higher viscosities, silicone is the best for temperature stability, but does shear thin. I can't however remember the other type of oil! I do know it was a bugger to clean off though.

I'd suggest trying some high viscosity 8th silicone diff fluids first - not 100% sure where to start though, I have hydra fluid at home so may be able to try and match it up by eye to my 8th oils?

IF you think the drive is changing during the run, then the silicone oil is probably shear thinning. However, thinking about it, another type of oil would probably be more affected by the temperature from the slipper part... :eh?: mmmmmmm

Perhaps the Schumacher one was better as it could use lower viscosity silicone oil, that wouldn't be as prone to shear thinning..... :eh?: I'm sort of thinking out loud here! :woot:

G

Custard

Fill your slipper with custard.

Its shear thickening!


We used silicone oils for our viscometer calibration too, but given that two different brands of viscometer could produce wildly different results with the same supposedly high grade calibration standard depending on what spindle and rpm you used I came to the conclusion that is all a bit made up really........

Wouldn't it be nice if someone at Losi was reading this and it inspired a new production run! I couldn't find any on Ebay - I'm sure a shop mut have one somewhere but finding one could be a long process.

For the fluid maybe an email to Losi would uncover the mystery of what to use - I'm sure they would just have bought some off the shelf stuff which was then re-branded and sold at 10 times the price.

For the science lovers out there here's a link to the patent

http://v3.espacenet.com/publicationD...=5178251A&KC=A

Are poeple needing the layshaft and slipper bits too?

when i emailed horizon UK about the hydra drive they said all the parts were still in production and they could get stock if need be, so might be worth getting your LHS to contact them to see what they can get you.

Ooh now that sounds good. Nice new one for my XX.

Hello,

Can someone advise me if you need a different layshaft to put the hydra drive on a CR??

Regards
Gareth

the xx and xxcr used the same gearbox so no need for new layshaft.

If you mean a xxx cr then I'm not certain but I'm 99% sure you'd still use the standard layshaft. - The reason being that the double slipper first appeared on the xx cr kinwald edition and was then carried over to the xxx series of vehicles, with the same plates etc.

a guy in the losi forum told me that it ran good with 10,000 weight fluid if this helps

Me again!

The hydra drive is meant to locate on the flat part of the layshaft I presume?? i.e. it is meant to locate and spin at the same rate as the shaft?? if so mine doesnt as the flat part of the layshaft isn't long enough.

Can anyone advise? i have found the below diagram, of which i have all the parts - just need to figures the layshaft query!

http://www.offroad-cult.org/RC-Lexik...ra_Drive_1.gif

Regards
Gareth

is part 3132 nearly flush with the motor plate?

if you can post up a pic of the shaft and ill tell you if its the same as mine

good luck