NjBasher

well i was in class thinking and i had this idea. what if the chassis was part of the suspension like literally. like make thew chassis absorbable per say. and each wheel would have its own suspension too i would have to draw a picture to be more clear but would this be a good idea?

Chris_RC

You need to actually listen in class!!! I have no idea what your saying. I think you have had TOO much time to think about this...

t-max97

My Feedback: (9)

+1

olkleaf

you mean something with this kind of suspension? [link=http://www.redrc.net/2009/01/motonica-p8c-classic-2wd-chassis/]motonica rc[/link]

other then that you make no seance

Access

With 'independent' suspension, each wheel already has its own suspension.
Anyways the idea of a suspension is to isolate any movement of the wheels from the main chassis, not the other way around.

SAVAGEJIM

I pondered this concept many times also, particularly in materials science class (And yes, I wasnt listening to the TA beecause got bored; I had already read the material the night before and alreay understood it, I could have just skipped class that day and slept in a little longer).

My concept was to actually have the chassis in two parts. The lower part would be made of elastic matrial that flexed. The upper part would be the regid part that containe all the essential components of the vehicle to make it go (engine, drivetrain, etc.).

The lower part of my concept would still have some sembelence of a classical suspension, but the shape of the lower part would have been a double wish-bone shape arched down with the dome-peak at the center of the belly of the RC. The arms of the wishbone would be the elastic part that has a moderate Hooke's constant, and to augment their functioning, each arm would have a conventional shock absorber.

The problem I foresaw is the arms could be hard to control, I mean as their movement path as they absorbed energy from bumps and hits and dips, etc. So, I began to daydream about the shape of each arm. The placement of material (making it thicker in the right places) can dictate how the amrs will move when absorbing energy, but then I began to daydream further and the next problem I foresaw is the performance of the material due to fatigue. I began asking myself, will the arms move in exactly the same motions it did when new? I know they will not absorb the same amount of energy anymore, fatigue reduces their Hooke's constant.

And in line with material fatigue, I als began to ask myself, just how long will such an integrated chassis-suspension would last? Well, as far as my design that is. If there are materials that are highly resistent to fatigue and can matain their mechanical performance over a long time, then the integrated chassis-suspension would possibly a feasible design, and not just in RCs, but possibly full sized cars as well. Oh, the money potential for inveting a successful prototype and selling that to the auto companies! And cars could actually be lighter too if the right materials are chosen.

Then I was shaken back to reality. The TA made us take a stupid quiz on stress curves.

NjBasher

ill draw up a picture on word or something as you can see the tranny is in the middle and the black circles are joints. then on each side will be a differential. then each wheel will have its own suspension

DaveG55

Jim, what's "TA"? Teachers Assistant??

SAVAGEJIM

Ah! MS Word! MS Word was my very first "CAD" program as I devised all sorts of gadgets in my head. I even turned in some physics homework drawn in Word (I was supposed to have used AutoDesk, but I was out late on the night before I had turn it in, was locked out of the student lab, so I resorted to drawing the vectors and objects in Word on my home 'puter, printed it up, and turned in he hard copy. I think I got an "A", mwybe a "B", I expressed everything I needed to get credit for the homwork!)

I am definitely interested in seeing what concept you have come up with. If you want to protect your idea, I understand, but if you are willing to share, just a very crude diagram will do.

BTW, here is a drawing I did in MS Word (My tribute to Keven Smith)

SAVAGEJIM

Yeah, I just called him the lackey for the professor when he was to lazy to teach the calss himself

K4neX

How about having suspension system like the ones on some rear sus*****on on real cars, separate damper and spring. That means the spring can be positioned at different locations on the suspension arms which provide more fine tuning on spring stiffness.

SAVAGEJIM

That is something I also daydreamed about too. But I was actually thinking about a variable geometry suspension even while the RC is in motion. But as for actually sensing initial forces such that the vehicle can predict which position to move the shocks to offer the best absorption, that unfortunately would require an on-board computer.

As for a variable geometry suspension while the RC is moving, I guess rigging up a servo on a free channel to actuate where the suspension components are moved to can be done, it's just you would have to vary the suspension geometry manually.

HJJFFFAA

^ To OP: Que?
< Is wondering why Silent Bob is so yellow.
V Gets what the OP said?

sheograth

That's exactly the same principle as any any independent suspension RC car works on already. Imagine that what you labeled as the tranny is actually a differential - that's a front or rear end. You have a control arm, joints, and a coil over shock.

The chassis is still separate from the suspension components, which are the control arms and the coil over shocks.

What you described has been done though, some pan cars and things have the rear mounted aft of a thinner section of chassis that literally flexes and absorbs vertical impact, this can be used with or without a shock absorber.

As others have said, you'd be best off listening to the teacher in school instead of trying to reinvent the wheel - unless you actually have an idea that's better....

SAVAGEJIM

^ Oh Yeah!
< Silent Bob is yellow cos MS word color slection pallet sucks
V More on the integrated Chasis-suspension

As for the axles on a pivoting comonent, it as actually been done. This mega-cheap go-cart is an example:
http://www.powersportsmax.com/produc...ign=Go%20Karts

The rear component is such a design, but the engine and drivetrain are actually integrated into that movable component.
MX dirt bikes also have a similar concept, a rear pivoting member and shocks to dampen.

I guess to make your idea work and be more in line of a chassis-suspension, make bothe the front and rear pivoting members just like in your drawing, but also install horizontally laid shocks as well that are parallel to the centerline of the vehicle. Add pivoting rocker arms to actuate those horizontally laid shocks.

See this link of what I mean by horizontal shocks (Traxxas Revo)
http://www.thebarnfloor.com/catalog/...roducts_id=679

But also, include you angles shocks as well.

NjBasher

actually i do have better ideas but i dont like to share cause others might steal my idea. and we were doing anything in class i finished a test and i was allowed to draw so i came up with that.

hands without shadows

Thats a terible idea for the front wheels. Anytime you hit a bump at speed the force will be almost parallel with the "suspension." It wont absorb much and it will probably break something. Thats why you dont see it used anywhere. The rear is ok and is used in things like four wheelers.

SAVAGEJIM

Good point! As the front compnenet pivots up, it will have a forward vector component, and that is a bad thing. A reaward component is desired, so rigging to forward component sich that it is reversed?

MadManAndrew

Hey Jim, you vever thought abou becoming an RC innovation engineer for hpi or Traxxas or something?

NjBasher

but that is going to be in the middle of the chassis

sheograth

So you're design calls for a rear solid trailing arm and a front solid leading arm - still nothing new.

NjBasher

no in the front and back are differentials that power the wheels

sheograth

Right, on their respective solid arms. It's nothing new, it's just different geometry.

EDIT - Do you mean there will still be A-arms perpendicular to the front - back axis? So basically the front and rear bulkheads can move relative to the center of the car? If so I can see how that's a bit new but I don't think it will be beneficial in anyway.

Chameleon1204

I actually have an idea of what he's talking about... IE: offroad, and coming into the turns, you want more steer in... more caster... when slowing for the turn, the weight is transferred forward:
conventional: caster is lessened due to body roll forward.
New idea: caster is increased due to weight and flex of chassis pushed forward.

When accelerating out of the turn:
conventional: caster is increased due to body roll backward with acceleration
New idea: caster is decreased due to same response of body roll.

the front bulkhead is attached at the top with a hinge pin, and at the bottom with a flexible joint that, with weight, lets the front drop slightly and increases the caster. the only problem I see with this is your steering links and ackerman. all these will change with relative movement of bulkhead with chassis.

good idea though. keep thinking!

SAVAGEJIM

I did, but I dont know if they would like my ideas, some are really out there.

Personally, I would like to have worked for one of the RC companies, but I wish they were still here in the US. They all wnet overseas to China and Taiwan.