low and high speed damping
 

Hi all,
Does anyone have an interest in hi and low speed damping?
And got any ideas why manufactures have not come up with anything yet?
Apricot Slice

Our shocks at the moment have adjustable high and low speed damping... ?

err.. is that a question or a statement?

I think it's been done yet, RPM used to make "2stage dampers", and at the moment there's the popular high end brand GHEA, who makes the 'tapered pistons' for several 1/10 en 1/8 kits, for the same purpose (low in, high out)

http://www.rpmrcproducts.com/faq/pistons.htm

http://www.ghea.se/index.php

http://www.oople.com/forums/showthre...t=29087&page=5

It's a statement, the question mark was in case I had picked up the wrong end of the stick and you had meant a difference in the car speed or something like that.

Any r/c shock out there reacts differently in high speed and low speed damping due to the laminar and turbulent flow of the oil.

I have seen the rpm pistons. you can use them as they state in the instructions to give more damping on the bound stroke and less on the rebound. this will help out on landings from big jumps. It will not improve handling though.
Fitted up side down it would act like typical low speed damping on a full sized car shock.



""It's a statement, the question mark was in case I had picked up the wrong end of the stick and you had meant a difference in the car speed or something like that.
Any r/c shock out there reacts differently in high speed and low speed damping due to the laminar and turbulent flow of the oil. ""

Yes, of course. the flow of oil passing through an aperture at different speeds has different reactions.
Take for example a B4 shock, or even a Tamiya Hotshot shock absorber which has a valve in it.. its all low speed damping.
Please take a look at the link to understand better the term high and low speed damping.
http://www.blackartdesigns.com/id4.html

A few have tried staged springs also, thats never really seemed to catch on though.. yet

Nothing about at the moment that I know of that allows you to tune high and low speed damping independently.

There are pistons about that allow you to adjust bump and rebound independently, such as Ghea and RPM.

I'm just starting to work on this for the RC world starting with proper damper dyno characterisation of all the current different damper pistons out there, will take a while to get results.

I assume you are refering to something like the platform damped shocks used on mountain bikes - which actually originated on real offroaders. These use variable pressure valves on the pistons to make the shock massively stiff (due to being over damped) to slow compression forces (such as those in cornering or accelerating) , but can be very soft and smooth for fast impacts (such as a bump).
Perfected it would allow you to set the car really soft for riding over bumps, without fear of it pitching and rolling into corners.

Basically the technology is simple enough that it could be fitted into an RC sized shock, but it wouldn't be possible to fit external adjustments (as on mtb shocks) and it would have to be a sealed unit (no oil changes) so ulitimately its not as good as we have now.

What I'm talking about is shock absorbers that work as they should.
Shock absorbers that allow the wheel to ride over the bumps and dips and maintain ride height and keep the tire in contact with the ground. Shocks that will bound rapidly without pack or over resistance to cope with the big bumps at speed without launching the car skyward.
So yes. like mountain bike shocks, racing car shocks etc.

If some sealed shocks appeared, as if by magic, on your car, (shocks that perform as their larger brothers do) it would be highly likely that they would out perform the competition in all situations anyway and negate adjustment.

External adjustment and sealed units pressurized with gas would not be manufacturable and be extremely complex. not to mention wildly expensive.

But however, there is a way of doing it cost effectively and maintaining the ease of use.

This sounds very interesting. Are you testing just competition shocks. Any particular scale?
What kind of equipment do you use to test them?

I'm going to be testing an AE shock with bleed cap with a variety of pistons, AE, 1,2,3, LOSI, Ghea etc and oils to measure what the real differences are rather than any conjecture.

Will be done on a full size Roehrig damper test machine such as this:

http://www.roehrigengineering.com/Pr...r-research.htm

How about something like the British Leyland Hydro-spastic? With a single oil reservoir, it'd be nuts, crap, oh and nuts.

It is possible to create a shock absorber from magnetic fields rather than oils, and the possibility is endless. But for me some of the enjoyment comes from the tuning of things like shocks, to remove this would remove it as a tuning factor, and remove any reward for making the car handle extremely well.

I will be interested to see the results. especially the comparisons with with the larger bore shocks.

Will you be testing for durability also?

Personally I like innovations and new stuff that makes things better and faster.

You could take existing real car technology.
Put a solid piston in, have a valve (or 2 stage/twin valve set) at each end of the shock, adjust them to activate at different pressures. Run a tube from top valve(s) to bottom valve to create oil loop. This means you could have fast and slow bump and rebound. Not rocket science.

Probably more advancements to be made with the delevopment of a diff unit that could do away with the slipper assembly rather than such over engineered suspension. Micro Hydradrive that replaces idler gear????

I would like to see a diagram of that.

doesn't have to be over engineered. I think it could be done with less than half a dozen easily manufactured parts.

er.. what is a micro hydredrive?

is a viscous coupling. Actually that would have to be on the layshaft gear rather than the idler.

The easiest way to make a piston with different bump and rebound is to have a piston with 4 holes in it with a reed valve on the top covering two of the holes. Going up the valve would be forced shut so only two holes are open, going down the valve opens and all four holes are open.

Its as simple as a disk of rubber clamped to the top of the piston using the c clip with only half of the holes in it that the piston has.

Easy peasy. :lol:

Are there any racers out there that would interested in more advanced shock absorbers?
(assuming of course that they would give you an advantage over the competition)