A simple idea that shows stagnation in CART/F1/IRL chassis design

[Franklin]

Here's a way of bringing some innovation into CART/F1/IRL cars without actually changing the cars all that much. The cannons and guns in the Messerschmidt 262 jet fighter were entirely contained in a detachable nose. To re-arm a 262, all the ground crew needed to do was detach the nose and replace it with a freshly loaded one. This same concept could be applied to Indy and F1 cars by installing the entire front suspension within a detachable nose (although it might be easier to do if the front wings were above the tires so you could move the suspension farther forward). This would be a big time saver in repairing a car damaged in a qualifying crash. Teams could even be given the
option of running a pullrod system instead of a pushrod system to see whether one gives better handling. A detachable nose would also take the inconvenience out of using a pullrod system since you could simply take the
nose off and flip it over to get easy access to the springs and shocks. Also, getting the front wings higher than the front tires would eliminate the many incidents we've seen in CART where a front wing on one car comes into contact with a rear tire on another car.

[TimD]

Now that's actually a pretty neat idea, Franklin. I like it.

It's not dissimilar to the arrangement of the DTM C-Class Mercedes about 1994, which had a detachable front subframe for quick engine switches. My memory is a little vague as to whether they had a similar back end for transmission/final drive swops.

The biggest hurdle to cross, I reckon, would be the risk of fundamental damage to the mounting points on the tub after collision. If the impact is anything like heavy, then a great deal of crush AND shear will be applied to the bulkhead to which the detachable nose is fitted.

Not insurmountable, but a real consideration.

Incidentally, am I not correct in thinking that the Me262 arrangement was an in-service shortcut hit upon by fast-thinking ground crews. The original, more orthodox plan involved a pair of centrally-hinged inspection panels which made up about 60% of the sheet metal on the aircraft's nose. The crews found the ease of removing the whole unit when they found themselves confronted with a chronic spate of nosewheel replacements. A notorious weak point on the 262, the nose oleo leg could be pulled out of true by incautious towing!

[ma]

Gee, for once you aren't totally half-baked, Frank !! Only 3/4 baked this time! Congratulations !!!!!!!!!!!!!!!!!!!!!

Pullrods were tried & discarded many years ago for many reasons : hard to get high enough motion ratios in such a confined space, upper a-arm has to be much beefier ( an unsprung weight disadvantage, which adversely affects mechanical grip, as well as much more prone to damaging the tub in a crash), the lower a-arm also has to be beefier to take the cornering loads, and the shocks are almost impossible to get at for easy adjustment, and usually run hotter because of the confinement. Been there, done that, threw away the t-shirt.

While on first glance this may seen as a good idea,but implimentation would be difficult to do at best and keep the tub rigidity up at the numbers we now enjoy ( around 40K lb-ft/degree, with some higher than that by a good margin). Not impossible, maybe, but the cost would probably be horrendous. And you complain about the current car costs ????!!!!!!

Front wing height : until mandated otherwise, no reputable designer would willingly raise the front wings and lose the ground effects. I thought you supposedly knew a bit about aerodynamics !

[Franklin]

MA,

A pullrod system is being used by an F1 team RIGHT NOW.

[Franklin]

"While on first glance this may seen as a good idea,but implimentation would be difficult to do at best and keep the tub rigidity up at the numbers we now enjoy ( around 40K lb-ft/degree, with some higher than that by a good margin)."

NEWSFLASH, MA. Although the engine in CART/F1 cars serves as a structural member it unbolts from the tub -- i.e., is detachable -- and is a much heavier and denser mass to hold in position than a detachable nose would ever be.

[Peter Mallett]

Originally posted by Franklin
MA,

A pullrod system is being used by an F1 team RIGHT NOW.

Yep. Arrows but it took a long time to get right.

[KC]

Looking at the detachable front clip idea from a manufacturing point of view. I am not sure if a strong enough joining structure could be formulated. The biggest hurdle the engineer has to overcome in chassis design is torsional rigidity. The cockpit of any race car is the weakest section of the car from a pure design standpoint. The open area where the driver must be and be able to work is almost like cutting the car in two. This large opening amplifies the twisting during extreme cornering, acceleration and braking imposed on the chassis. By attaching the entire front clip (which includes front suspension and the front wing element) at one point you force the front edge of the tub to support too much force. In the event of a wreck this would most likely be the first place to fail and leave the driver terribly exposed to injury. Short of being able to replace the entire front clip in the event of damage, I think there is little to be gained from it in major forms of open wheel racing.

The wing-to-tire contact problem is one that will never be solved in CART/IRL/F1 unless the front wings are removed. The closeness of the front wing to the track surface creates more traction and downforce. Also, it keeps the tires from coming into contact. Contact between two tires, not on the sidewall, will almost always result in one of the cars being vaulted over another. All of the sanctioning bodies have instituted rules that require the teams to have blunted edges on the front wing plates, thereby limiting the number of wing induced punctures we used to see.

[Franklin]

KC,

Despite the leverage created by the distance between the rear suspension and the rear bulkhead of the tub, the rear bulkhead manages to support the vertical, torsional and lateral loads generated by the rear suspension (and in turn the vertical and lateral loads imposed on it by the mass of the engine). Given this, I see no reason at all to believe that a similarly strong coupling could not be developed for the front end of the tub (particularly as how they always seem to be increasing the footbox strength anyway). The vertical, torsional and lateral loads created by the front suspension are going to be present on the front of the tub whether or not the nose is detachable.

[TimD]

Yes, the loads are there whether or not the nose is detachable.

But not focused on one part of the tub, which will be, by necessity, close to the cockpit opening.

As to the question of strengthening, that is also feasible, but it starts to run up against every speed shop's maxim, to "add less weight". It will not take much bracing of the unorthodox structure before you lose in weight penalty what you gain in theory in ease of service.

[Peter Mallett]

From a layman's point of view it sounds quite good. however I can see a downside in that the set-up time would be just as long. So the quick change advantage gets lost because you need to spend time setting up more than one set of suspension. Nice thought though.

[Franklin]

"It will not take much bracing of the unorthodox structure before you lose in weight penalty what you gain in theory in ease of service."

That's certainly always possible, and perhaps the most difficult of the solutions that would be needed.

[KC]

The biggest obstacle to overcome, I think, would be the fact that the driver's legs and feet protrude through the front attachment bulkhead, where there is only a small series of openings in the rear of the bulkhead for wires, cables, and other hoses to engine. The opening required who seriously reduce the strength and attachment opportunities available.

[Dino IV]

Plus the rear suspension-to-tub joints have to be placed in front of the driver's main tub, to be on the switchable nosecone. That will be way to much to the front and thus create a longer wheelbase, which is an extremely critical succesfactor in F1.

But as stated there is defenitely much room for improvements in the quick change departement. A fastly replaceble rear-wing alone would be a big step forward and even that's very difficult to accomplish.

The DTM\ITC Class I Mercedes C-class was probably the most advanced car ever engineered in this aspect (and most other fields of engineering too btw ). Really a masterpiece.

[Franklin]

Although a longer wheelbase may not be a bad idea on an oval track car, the wheelbase issue is certainly number one on the list of things an F1 designer would have to look at before considering a detachable nose concept.

[Sparky]

One point worth mentioning are controls. The detachable nose concept would entail disconnection of the front brakes (obviously). This would, I assume, involve new master cylinders, linkages etc - the whole kit. How would a safe, effective, adjustable 'quick-connect' brake balance system be incorporated? Does the driver still control suspension elements - anti-roll bar, etc? How would this be achieved 'on the run'? And steering? Could a steering disconnection/reconnection be quickly, yet safely, implemented? Having a fragile steering connection cost Senna his life.

The 'new nose' idea is a good one, but if the only damage is to the front wing (as is often the case) then a new nosecone/wing is easily replaced with little effect on other components. To get involved with replacement brake, suspension and steering systems, at 'race pace' would be unnecessary. Chances are, if a car loses a front wheel, or sustains suspension damage out on the track, that is where it stays.

My two cents.

[ma]

Pullrods:

Considering that March tried & discarded it back in the '80s, Lola tried & discarded it, Ferrari, McLaren, Lotus, etc., etc., I somehow doubt that Arrows can be accused of knowing something that everyone else doesn't, especially considering their performance reletive to everyone else at the moment ! That doesn't mean that it isn't useable under certain circumstances, but most top current designers would be loath to compromise in that direction (unless there were one hell of an aero advantage somehow)!

On the nose front - auto acting quick disconnects can be employed to take care of the steering column, brake lines, data aquisition, brake bias controls, etc., but that isn't the real problem with this thought.

On most cars the engine-tub connection is structurally the weakest area of the car, and quite often the least stiff torsionally (yes - even weaker than the cockpit with its big opening). In fact, on most designs it is deamed desireable to have the car break there, AND leave the tub rear bulkhead intact, in a severe enough crash in order to dissipate a lot of energy that the tub might have to absorb in a second or third hit. To produce a design that has the potential to allow the car to break in half & expose the driver would be unacceptable to every designer out there, never mind the drivers, sanctioning bodies, and insurance companies, not withstanding the need to keep the car as stiff as possible.

Lengthening the wheelbase enough to put the entire front suspension ahead of the driver compartment is not an option unless minimum weights are raised substantially enough to allow ballasting the front enough to keep the correct percentage of weight on the front tires, never mind keep the CG/CP reletive locations at or near the ideal.

OK idea on the surface, but I doubt it'll ever happen.

[ma]

Hey Frank !

Why no snappy reply about your goof about front wing height ? Or were you hoping we'd not notice ? NEVER !!!

Come on now, let's hear something really original this time !

[Franklin]

MA,

You mean such as using airfoil sections designed to work in a freestream instead of ground effect? LIKE THEY DO ON THE REAR WING RIGHT NOW.

[THR]

rear wings are less effecient than front wings cos they have no ground effect.

pull rods are better as the centre of gravity is lower because the mass of the shocks is as low as it can be. that is the main reason for it., yea the drivers legs are a bit higher. but gains out wiegh the dissadvantages.

the arrows out handles most of the grid! **** drivers, **** engine. and still quick.

as for franklins idea.
are u lot mad even considering it?
the problems out wiegh the gains.

the location on the tub would have to be amaziling good to get the corner weights right!
bin the idea!

[THR]

oh the s word is kinda censored! hehehe

[Franklin]

THR,

At Le Mans this year, Audi demonstrated they could change out everything behind the engine in five minutes.

A front wing only slightly above the ground does have substantial disadvantages in addition to advantages. Current front wings have to be designed so that they don't disrupt air flow into the radiator inlets. This means flaps, winglets, etc have to be mounted toward the outboard end of the wing. The low height of current front wings also means they are well and truly engulfed in the turbulent wake of cars ahead.

(Carp with the a and r reversed won't make it past the software filter either.)