hornet rear suspension

[shenlonco]

Reason why what ever you do to a hornet rear suspension it won't ever work.... Oil shocks , wieghts....

The suspension was made so wrong that when you go farward it literly forces the rear shocks to extend to thire full limits because the chassis wants to go up and the rear down from the angle the rear is held on to the chassis fom farward tourque of the motor.

THE TEST

get your car with a hornet type suspension set up

put the front up against a wall and give it a little gass you will see the rear shocks naturally are forced to pull out and lifts the car now when doing this try pushing the rear down you will find it can't go down as its locked and you would need alot of force to push it down ...that's why they always bounce no matter what you do because the supspension only works when you are not giving it farward gas and when you are and there is resistance on the car going farward the rear suspension is locked up.

rear shocks are actually holding your rear on if they where off and you floored it the rear would flip under and try to go farward under the chassis !!

[TA-Mark]

The problem with your theory is:

When, under normal driving conditions, is there resistance to the front wheels or front of the buggy similar to parking the buggy against a wall? The front has no brakes, no drive, and little rolling resistance. Only under hard take offs, in very good traction situations (like my wheelstand video) does the rear suspension 'lock up' under normal use.

Most times with this type of buggy you are off the throttle, or holding the throttle steady as you head over severe bumps or jumps. Admittedly, it's not the best suspension setup out there and the use of soft springs, soft damper oil, and weighting rear of the main chassis is making the best of a bad situation. In real world driving situations this helps it keep it's rear wheels touching the ground emmensely over the stock setup.

[WelshHornet]

Hi,

Does this happen with both stock friction dampers from the early hornets and the oil filled hopups / re re standard part?

I've always thought (please no one from nasa come on and bash me to death here ) that the lifting of the front that starts the wheelie, would negate most the other forces on the back? I doubt that wing causes any true aero as well. When i was a kid i used to park the hornet against my foot and floor it to get a huge burnout going, are you trying to do the same thing?

[shenlonco]

Tried weights and lighter springs and oil with weights it's not making the rear suspension work any better (shocks compressing ) it still stays locked up when running and your just weighing down the car it hops around still just that it don't go off the ground as hight because it's just heavy now...not because suspension is working.

Sure it will work better when letting off the gas just coasting since that's the only time it can work.... but when giving the car gass seeing dirt flying from the rear tires all the time that's putting so much pressure on the car the gear box stays lifted in the hight point of the swing position.

You can put your car in sand or low grass or dirt or even going up any slight incline give it a little gass and you will still see the rear stays pushed up in the chassis slots... just from the weight of the car makes it tourqe up in that position.

Funniest thing if you lock it down like in a grasshopper the rears angle point like this actually makes the suspension work better it don't get nearly as much as that pop and pull to the shocks pulling them open... my brother in law has a grasshopper we raced them in a baseball field on a track we put up and the hornet looked like it bounced and hopped more than the grasshopper?

It's that pivot point when it pops the gearbox where it connects on the chassis upward this makes the rear suspension lock and not be abale to compress...and in the down position it don't do it to much.

The problem with your theory is:

When, under normal driving conditions, is there resistance to the front wheels or front of the buggy similar to parking the buggy against a wall? The front has no brakes, no drive, and little rolling resistance. Only under hard take offs, in very good traction situations (like my wheelstand video) does the rear suspension 'lock up' under normal use.

Most times with this type of buggy you are off the throttle, or holding the throttle steady as you head over severe bumps or jumps. Admittedly, it's not the best suspension setup out there and the use of soft springs, soft damper oil, and weighting rear of the main chassis is making the best of a bad situation. In real world driving situations this helps it keep it's rear wheels touching the ground emmensely over the stock setup.

[WelshHornet]

Theres a bloke on ebay who sells the axle lower shock mounts but they're for placing the suspension further back. Have you considered something like that over Tamiya standard mountings?

I know its not totally curing the problem but these things can be tweaked to death and back with huge differences. I'll get a link and PM you if interested.

[shenlonco]

Theres a bloke on ebay who sells the axle lower shock mounts but they're for placing the suspension further back. Have you considered something like that over Tamiya standard mountings?

I know its not totally curing the problem but these things can be tweaked to death and back with huge differences. I'll get a link and PM you if interested.

That may help a little because it would make the angle different.

[WelshHornet]

That may help a little because it would make the angle different.

hornet mounts on ebay

A friend and i are currently rebuilding one of my spare hornets using these, no running report yet but when its finished i'll let you know. If they work i'll add them to my basher.

They're delrin tyre material when they arrived and seem to be very high quality.

[matman]

You could try these as there is more adjustment's to be made for the rear shock . junfac .

http://www.junfac.com/shop/index.php?main_...products_id=418

Hope this may help , I saw it a few days ago & had to remember where i saw it . Big head strain trying to remember

[TA-Mark]

The Hornet has always had oil dampers on the rear and friction dampers on the front as far as I've ever known.

I'm not running Hornet dampers, which may very well be why mine works. My rear suspension is very smooth and light, with about 100grams of lead above the dampers inside the spare tyre.

You can see in this photo that I'm on the power, with roost coming off the rear tyres, and the rear suspension is more compressed on one side than the other (rolling diff centre), and the rear suspension is not locked at full extent. The body is Grasshopper, but the chassis is Hornet. The Hornet chassis now runs a Roadrunner II body.

[tonysmini]

you could try placing some small springs inside the shock on the shocks shaft to counter-act the shock bottoming out in it's fully extended state under acceleration. (Like a shock spacer but with a bit of give in it) I have heard of people using click top pen springs for this, but they'd have to be pretty strong ones.

As for the gearbox front springs, I made a set for my Pumpkin years ago from nappy pins, cut and bent to fit. They worked much better than the original tiny things until I did my 3rd shock mod.

[HunterZero]

Bear in mind that if you are using the soft kit tires on the Hornet, these absorb a good amount of the bumps before the shocks compress. I'm pretty sure it was designed to work this way.

If you get the Frog hex wheel adapters and swap to more modern lower profile rubber, you'll work the rear shocks harder.

- James

[B.M.T.]

I've put some thought into this subject, and it comes down to this:

Torque twist / reaction.

When you accelerate, the front of the tyres want to go down, and equal and opposite, the front of the gearbox goes up. When it can't go up any more, the energy is redirected to forcing the rear of the gearbox down, a. forcefully full extending the shocks and b, fully extending the rear suspension, resulting in the suspension being "locked" by this reaction to the wheels trying to drive the car forward.

This now solid suspension causes a flow on... The sudden downward smacking of the rear wheels and jamming of the shocks causes the back of the car to bounce off the ground, but the instant the rear wheels touch the earth there is the need to push forward, the gearbox twists back again causing the rear wheels to hop again.. and the circle continues until power to the motor is turned off.

So, you could theoretically drive a Hornet without rear springs. The opposing reaction to the rear wheels spinning forwards would jack up the rear end. So, no matter how much you try to soften the rear springs, it won't help.

One of the biggest flaws in this design is mounting the shocks behind the axle. short stiffer shocks mounted closer to the chassis pivot would of controlled this a little better, but not much and the suspension would not work much better than a Marui Super Wheelie or Big Bear. They do actually seem to absorb bumps to a degree.

The way to fully fix it? Fit parallel 4 link suspension with a panhard rod, much like the rear of an old Carlton or Mk4 Cortina so all the torque reaction is absorbed in the geometry of the linkages and it allows the axle to freely float like a real Hochkiss drive suspension.

[shenlonco]

I've put some thought into this subject, and it comes down to this:

Torque twist / reaction.

When you accelerate, the front of the tyres want to go down, and equal and opposite, the front of the gearbox goes up. When it can't go up any more, the energy is redirected to forcing the rear of the gearbox down, a. forcefully full extending the shocks and b, fully extending the rear suspension, resulting in the suspension being "locked" by this reaction to the wheels trying to drive the car forward.

This now solid suspension causes a flow on... The sudden downward smacking of the rear wheels and jamming of the shocks causes the back of the car to bounce off the ground, but the instant the rear wheels touch the earth there is the need to push forward, the gearbox twists back again causing the rear wheels to hop again.. and the circle continues until power to the motor is turned off.

So, you could theoretically drive a Hornet without rear springs. The opposing reaction to the rear wheels spinning forwards would jack up the rear end. So, no matter how much you try to soften the rear springs, it won't help.

One of the biggest flaws in this design is mounting the shocks behind the axle. short stiffer shocks mounted closer to the chassis pivot would of controlled this a little better, but not much and the suspension would not work much better than a Marui Super Wheelie or Big Bear. They do actually seem to absorb bumps to a degree.

The way to fully fix it? Fit parallel 4 link suspension with a panhard rod, much like the rear of an old Carlton or Mk4 Cortina so all the torque reaction is absorbed in the geometry of the linkages and it allows the axle to freely float like a real Hochkiss drive suspension.

well said and me and my brother in law proved this with using light springs stiff springs thin oil thick oil just springs no oil and even did the weights nothing works at all like you said it's the nature of how the suspension just naturally works ...

[TA-Mark]

The way to fully fix it? Fit parallel 4 link suspension with a panhard rod, much like the rear of an old Carlton or Mk4 Cortina so all the torque reaction is absorbed in the geometry of the linkages and it allows the axle to freely float like a real Hochkiss drive suspension.

Mk4 (TE) Cortina does NOT use a panhard rod, that's a GM thing. Look again, it's a Watts linkage like that under an XE Falcon ( and later models until Falcon went IRS). V8Supercars still use live axle, 4 link with a Watts linkage. This type of suspension suffers severe torque twist when large power is pushed out through the diff. CC01 will lift one front wheel off the ground on hard take off even with the standard motor fitted, just the same as my 5.0L TE Cortina will.

[B.M.T.]

Mk4 (TE) Cortina does NOT use a panhard rod, that's a GM thing. Look again, it's a Watts linkage like that under an XE Falcon ( and later models until Falcon went IRS). V8Supercars still use live axle, 4 link with a Watts linkage. This type of suspension suffers severe torque twist when large power is pushed out through the diff. CC01 will lift one front wheel off the ground on hard take off even with the standard motor fitted, just the same as my 5.0L TE Cortina will.

I am aware of Ford's use of Watts linkages, I just abbreviated the description in the post above to simplify the example. Panard or Watts, that has no effect on the torque twist that lifts a wheel. Any full size car with a live rear axle that is suspended and has enough torque will twist against the direction of the drive shaft. All that a Watts does keep the axle centred while it's moving through it's suspension range, the Panhard forces the axle to track through a radius. So for the example in my post it's a moot point. Someone could fit unparallel 4 link like a CC01 to a Hornet but it would be impractical with the space available.

[WelshHornet]

The Hornet has always had oil dampers on the rear and friction dampers on the front as far as I've ever known.

I'm not running Hornet dampers, which may very well be why mine works. My rear suspension is very smooth and light, with about 100grams of lead above the dampers inside the spare tyre.

You can see in this photo that I'm on the power, with roost coming off the rear tyres, and the rear suspension is more compressed on one side than the other (rolling diff centre), and the rear suspension is not locked at full extent. The body is Grasshopper, but the chassis is Hornet. The Hornet chassis now runs a Roadrunner II body.

my mistake then, i got my early hornets 2nd hand a long time ago from a guy who used to race them. and they both had friction dampers, was that one of the differences between hornet and grasshopper then?

[TA-Mark]

my mistake then, i got my early hornets 2nd hand a long time ago from a guy who used to race them. and they both had friction dampers, was that one of the differences between hornet and grasshopper then?

Grasshopper has only springs on the front, friction dampers on the rear and a fixed pivot rear diff. Hornet has friction dampers front, oil dampers rear and a rolling rear diff.

If you find the rear suspension so bad, convert it to IRS (which has been done before). IMO this mod removes the characteristic that makes a GH/Hornet what it is.

[shenlonco]

Grasshopper has only springs on the front, friction dampers on the rear and a fixed pivot rear diff. Hornet has friction dampers front, oil dampers rear and a rolling rear diff.

If you find the rear suspension so bad, convert it to IRS (which has been done before). IMO this mod removes the characteristic that makes a GH/Hornet what it is.

No i like the way they drive that's what makes them fun to run but i always see and hear guy's going nuts trying to make the rear suspension work better and i went thought it also that's why i posted this as i feel it's a waste of time because of it's faulty desighn so leave it as is for what it was and just go out and have FUN with it.

[Sayer]

*never mind, I can't read apparently.

[Coopdevil]

This got me thinking during the afternoon in the office about whether this applied to my Rising Fighter as well.

I recently put oil dampers on it and on the grippy tarmac in my cul-de-sac the front was planting itself to the point whereby the rear would hop up and down until the car built up some momentum and then started rolling. Absolute rubbish. Anyway, following on from the train of thought in this thread, I swopped out the front wheels for some spare DT-01 fronts off a dead Fighter Buggy. The original Rising Fighter wheels are quite wide and effectively slicks with three shallow grooves in them, the replacement fronts are blade-types for loose surfaces. Much less contact patch. The front-end-stays-still-rear-end-jumps behaviour immediately ceased. So yeah, perhaps rolling resistance at the front is a big factor. Certainly the RF seems to handle a lot better now.

Coop

[TA-Mark]

Rising Fighter and the DT01 chassis series have the same suspension issues as the GH/Hornet based models. Single wishbone front with odd camber angles and massive bumpsteer, and a rear suspension that works badly at the best of times.

[taliesin]

Rising Fighter and the DT01 chassis series have the same suspension issues as the GH/Hornet based models. Single wishbone front with odd camber angles and massive bumpsteer, and a rear suspension that works badly at the best of times.

What is this "suspension" thing you speak of on the DT-01 and Hornet?

[WillyChang]

biggest improvement to our Hornet has been modern grippy rubber at rear

front doesn't really matter; if its really rough then 2.2" wheels are better

using GH's pixed pivot makes it more predictable too imho

prior had bought a pile of Hornet pivot springs to experiment with, but they all don't do much good

also make sure your ESC to motor wires aren't hindering the suspension movement

[andy_t]

What is this "suspension" thing you speak of on the DT-01 and Hornet?

I have no idea - but it didn't stop me trying to turn it into a drift racer

Stable as you like, despite chattering from inside rear wheel under power, as it bounces up and down.

(BTW this is an excerpt from a 10 min video of me flattening the battery in a disused open car park. The rear tyres are already worn down to slicks.)

[matman]

Mk4 (TE) Cortina does NOT use a panhard rod, that's a GM thing. Look again, it's a Watts linkage like that under an XE Falcon ( and later models until Falcon went IRS). V8Supercars still use live axle, 4 link with a Watts linkage. This type of suspension suffers severe torque twist when large power is pushed out through the diff. CC01 will lift one front wheel off the ground on hard take off even with the standard motor fitted, just the same as my 5.0L TE Cortina will.

You got a pic or the 5l TE , Always wanted one of them . But all i got is a 5l MK1 Escort .

Build it my self , was going to put the 4 link in , but was cheaper to use the leaf spring with 9in .