Interesting Item on New Chassis in Indy Star (Merged)

[bjohnsonsmith]

Originally Posted by Tim Northcutt

Let's see what they come up with at the end of the game...

That's an eclectic mix, with two of the board coming from F1/Jaguar and having worked with Ford.

Interesting how Gil de Ferran's two CART championships in 2000 and 2001 weren't mentioned.

Indeed, let's see what they do come up with. Is there a deadline?

[JagtechOhio]

HOME RUN
Touch 'em all

[bjohnsonsmith]

Originally Posted by JagtechOhio

HOME RUN
Touch 'em all

Jag, you're the best person I can think of to ask this question to. What is the difference between a stressed and un-stressed engine and what does that difference have on engine performance?

[JagtechOhio]

Working on the pictures, hang on.

[JagtechOhio]

Honda HI6R, same as today.
Mounting stud bosses clearly visible at front (left of photo)
Two each cam cover, two at base of block
Six studs at rear of block for differential housing mounting, three pictured



That's the really small flywheel, this one is goint to get plugged on the six studs sticking out of the back of the tub.

That's a stressed engine installation. The block has to be specially manufactured with the mounting bosses, and designed to take all of the torque load imparted by the rear suspension. Strong block. There isn't any frame or other support structure: Tub, engine, differential/geabox, done. Rear suspension is mounted to diff/ gearbox.


That's the back end of the car, only this is the Dyson Lola ALMS car. The differential and input shaft is facing front. You roll it up to the back of the engine, hang it on the studs sticking out of the back of the block, and start plumbing.

Photo credit: Marshall Pruett

That's the Dyson Lola with the 4 cylinder turbo AER 2.0 Liter installed.
This is a semi-stressed installation: a small aluminum block can't handle the chassis torque loads.

So the engine is mounted on studs at the rear of the tub, but it also has "A" frames either side which are essentially removable chassis rails. The left side A frame is visible here (chrome). That ties the loads from the differential mounting crossmember to the rear of the tub.

That is the setup which would be required to plug a stockblock Ecotec onto the back of a Dallara. An adapter plate bolted to the front of the block which hangs on the six studs at the back of the tub. Then A frames or X braces to tie the differential/ gearbox onto the back.

The big deal it that the chassis has to be rigid when it's complete. You can measure this, it's not magic: but torsional rigidity is essential, or your corner weights are not consistant (the late 70's and early 80's Eagles had this problem).

I think the addition of a carbon fiber undertray (above the standard undertray) could also be added to act as a tub extension, and help stiffen the engine bay as well. Mounts to the back of the tub and the bottom of the diff/gearbox housing.

One of the designers tells me you couldn't make it stiff enough to handle the loads at 4 g's at the Speedway, and also says that the structure would be insufficient for crash durability. Maybe he's right, he wants a stressed engine V6. That's very similar to the top pictures, and the current V8 installation

What the other designers think isn't clear. The Delta will look very similar to the Dyson Lola I expect, they are using the same AER 4 cylinder engine.

The Dallara numbers came out almost identical to mine, so I don't see how they are building a car as light as they plan with a V6 turbo in it.

For me, that's about as far as I can go. It will take an engine on a dyno to prove the output and durability, and there is a good chance that the job can be done reasonably. It will take an engineer to calculate the stress loads, there are guys who could do that pretty easily.

Or you bolt a 4 cylinder block on the tub, hang the rear suspension on, and measure the torsional rigidity. If you can reinforce the engine bay properly, you can do it. Flex in the entire assembly is the killer.

The Dyson Lola did, and it is a wider and heavier car. The existing Dallara chasis would be even more capable, IN MY OPINION.

A non-stressed installation is what is in your car, or in a typical Formula Ford. The chassis is build independantly, with the frame or monocoque having its own rigid structure, and the engine just drops in. That's the basics, it's a "one piece" chassis. The stressed and semi-stressed are "three pieces"...tub, engine, a$$ end.

Edit for bjohnson: stressed, semi-stressed and non-stressed has absolutely nothing to do with the performance characteristics of the engine. The only relationship would be a stressed engine installation of a block that is not strong enough to handle the chassis torque loading: then the internal dimensions of the engine are not maintained, and very bad things happen.

[Canada ALMS fan]

Thanks Jagtech, possibly your best post ever of very many good ones.
Very informative. I always thought unstressed meant an engine or block was running within the performance limits of the production version. IE. maybe better pistons, injectors, and crank but same redline, no cylinder sleeves, long life, etc.

[bjohnsonsmith]

Originally Posted by JagtechOhio

Edit for bjohnson: stressed, semi-stressed and non-stressed has absolutely nothing to do with the performance characteristics of the engine. The only relationship would be a stressed engine installation of a block that is not strong enough to handle the chassis torque loading: then the internal dimensions of the engine are not maintained, and very bad things happen.

Thanks very much and you certainly went to some trouble to explain what a stressed or semi or non stressed engine is. The pics really help and help give me a much better idea of your proposal. The edit was very helpful.

[JagtechOhio]

To Canada:

Cheers mate, I'm ciphering on it. Talked to Rhys Millen Racing today about the 500+ HP Ecotec they ran in '06, the dude was so helpful it knocked me out.

Still waiting to hear on the Ford Duratec. Maybe all the guys on the Iconic panel already had all of this stuff handled, we'll see.

You're talking about "stress" too, but those are internal stresses. Like stock connecting rods breaking at 300 HP, or valve springs breaking at 10,000 RPM. They can't handle the stress, but it's different than what bjohn was asking about.

The cool thing for me was finding the picture of the Dyson car...that's the whole package, right there. And with the redesigned engine cover, it's a new look Dallara like the blue one in the rendering back earlier in the thread.

[JagtechOhio]

Bjohn:

cheers, mate. I'm glad you asked, it helps me to tie all this stuff up into a package that is easier to understand.

And keeps me wondering why all we hear is "we're talking to the manufacturers at an engine summit".

The engine builder named to the ICONIC panel, I didn't even know about him. Big time builder. He's the perfect guy to oversee the dyno testing at his shop in Indy, if they just mail the invitations.

[Canada ALMS fan]

Originally Posted by JagtechOhio

To Canada:

Cheers mate, I'm ciphering on it. Talked to Rhys Millen Racing today about the 500+ HP Ecotec they ran in '06, the dude was so helpful it knocked me out.

Still waiting to hear on the Ford Duratec. Maybe all the guys on the Iconic panel already had all of this stuff handled, we'll see.

You're talking about "stress" too, but those are internal stresses. Like stock connecting rods breaking at 300 HP, or valve springs breaking at 10,000 RPM. They can't handle the stress, but it's different than what bjohn was asking about.

The cool thing for me was finding the picture of the Dyson car...that's the whole package, right there. And with the redesigned engine cover, it's a new look Dallara like the blue one in the rendering back earlier in the thread.

If you need photos of engine installs in LMP1/2 cars from the past 5 years let me know, while not a photographer I may be able to help as I have spent many a day in the ALMS paddock.
As for ICONIC, do you think it will really be subjective enough to get any real change? More than a couple of those appointments could be scary depending on their agenda. I really hope they get this right.

[Purist]

Jag, do we know how much ballast the Dallaras are carrying? I would think it's a safe bet that they're carrying some amount, just not sure how much.

i'd be concerned with lightening the cars too much; we saw the consequences of an F1 car hitting the wall at Indy at speed, but still not at the sort of speed they'd be doing if they ran the oval in its entirety. And yes, I checked, according to Appendix O of the FIA regulations, F1 cars ARE approved to run on banked speedway ovals.

I'm not certain whether or not the un-stressed set-up would be able to take the g-loadings of Indy or the other ovals. None of the tube framed racing cars I can think of turn more than 2.0-2.5g in all likelihood.

My greater concern in some ways is that those extra frame rails and such could prevent, or at least make more difficult, the rear-end separation that occurs in some of the most violent crashes. Having that material break away in such a harsh impact is definitely a good thing for the driver, and how much energy ends up being transferred to his or her body.

The materials themselves that were used at the time aren't exactly comparable, but I would think that Colin Chapman's data on the old Lotuses might very well give us useful information on the relative difference in torsional rigidity between the different chassis types, and of course, the Lotus 49 was the first to have a stressed engine, so the Lotus archives should shed some light on that particular aspect as well.

[JagtechOhio]

Nobody knows how much ballast a Dallara is carrying until the driver is selected for it: then an equivalency weight is added, based on the driver's weight. That's to prevent Danica from having a 50 lb weight break from Justin Wilson, as an example. The mandated amount of ballast is then placed in the bottom of the fuel cell compartment in the tub.

There won't be a specific figure available to determine weight with no ballast, unless you are weighing a new chassis. Sarah Fisher was running a tub last year that was 22 lbs. heavy, thanks to many years of crash damage repairs. Whether that means the complete car still got some ballast, or no ballast, or was overweight...don't know.

What are Mr. Dallara and Mr. Toso planning to do to reduce the current weight by 140 lbs when they design the new chassis? I have no idea. It won't be achieved by undermining the integrity of the tub, subtracting crash intrusion material from the sidepods, or deleting the attenuator.

All of the weight reduction I proposed to the current chassis would be achieved by substituting an engine that is at least 50 lbs lighter, and enabling the installation of smaller ancillaries...as mentioned, oil tank, oil cooler, and radiator would likely be sufficient at reduced capacity.

Exact comparisons are impossible without selecting the specific components to be installed, sorry to disappoint. I don't know how large an air-to-air intercooler will have to be, so I can't figure out its weight. Weight of the turbocharger required? No answer. Weight of the engine bay reinforcement required? No answer. Those are engineering determinations.

Do you need two pairs of 180 degree headers and two mufflers for a four cylinder turbo? Nope, throw them away, along with the airbox. Less weight, less drag horsepower loss.

Presuming that a 4 cylinder turbo will get significantly better than 3.5 MPG, the Dallara/ turbo now can carry a lighter fuel load:

22 gallons X 6.6 lbs/gal.= 145 lbs. That gets you 77 miles @3.5 MPG.
15.4 gallons X 6.6 lbs/gal.= 102 lbs. That gets you 77 miles @ 5.0 MPG

So if the lighter turbo engine car (with less drag) gets you 5.0 MPG, it also starts a fuel run 43 lbs. lighter than the V8 car.

Or, you start the race full (by current regulation) and go 33 miles farther than the V8 car. Now you have comparative speed differential as the fuel loads decrease at different rates, and a variety in pit stop strategies. Different acceleration rates with peak HP output matched.

Those are bad things?

Establish necessary equivalency by adding or subtracting ballast, and light 'em up. Maybe the V8 gets a ballast reduction, or the turbo four does.

I haven't recommended anything else to reduce the weight of the current car. No discussion about lightening the car is relevant to crash safety, except two immediate advatages: likely less fuel on board, and less force generated on impact by the reduced overall weight of the car.

Now we go to the issue of the cars breaking in half in crashes. There are ways to control this to some degree, and I do not know what result the current design criteria is expected to produce. Do you?

Normally, when you build a race car, you design shear points into individual components. One convenient example would be suspension mountings: either wishbones are designed to fail, or shear plates (or clevises) are used for their mounting. When wheel contact inevitably occurs it does not result in damage to the tub bulkhead mounting points. Check the bulkhead and the tub, hang a new corner on the car and go out for the next session.

So their are two ways to handle the rear bulkead mounting of the engine. If you do not want the car to break in half, you make those six mounting studs sticking out of the tub very strong indeed. And the bosses on the engine which are bolted to them, and the rear bulkhead attachment to the tub.

If that's a really strong mounting, it will take a massive crash to break the car in half. That also means that severe impact to a rear wheel will break the weakest link...the gearbox housing? The engine block? The rear bulkhead in the tub? Depends on where you want it to break.

If you want the car to break in half, the mounting studs would be designed as the shear points. Car gets hit hard, studs break. That way, in less severe incidents, the tub mountings are not damaged, or the engine mounting bosses bon't get cracked or broken off. Pull the motor, change the studs, but you didn't junk a tub. Maybe you didn't break your motor, either.

It's not a problem to design this consideration into the car, it depends on what you want to see as the result. One designer wants a stressed-engine V6 to help prevent pieces from being thrown off in a big wreck. I don't know if his thoughts on "rear-end separation" are the prevailing wisdom or not. He seemed to indicate this was a bad thing.

Adding A frames or X frames to the engine bay doesn't change any of that a bit. If you want the car to break, the frames attach to clevis brackets at the rear bulkhead which are designed to fail on severe impact, just like the engine mounting studs. If you don't want the car to break, make it all as beefy as you want. The strength of the rear bulkhead and its bonding to the tub then becomes the determining factor. You want the bulkhead to stay in the tub, it protects the driver.

None of this is comparable to tube frame cars, period. The 4 cylinder turbo would be a semi-stressed installation. That means it is just like the Dallara/ Honda, with the addition of reinforcements to compensate for the loss of the engine bay rigidity that the big V8 block provides.

You bolt the little block onto the tub studs with a mounting plate, reinforce the engine bay, and measure the chassis deflection with the rear end hung on the car, period. If you can't control the torsional rigidity without adding a massive cradle or exceptionally heavy bracing, it won't work. Chassis deflection is the killer.

Not only does it result in uneven corner weight distribution in response to changing load, but it also introduces a "snap back" effect to make the deviation even worse. Think twisting a ladder. Think tube frame. That's why tube frames don't work, unless the chassis is really light. Like an ancient Cooper, which was strong enough not to twist but not adequately strong enough to protect the driver.

Build a tube frame strong enough for the job, and it weighs a ton. That's why race cars are carbon fiber monocoques, and designs move forward from current standards to new ones. Backwards gets you backwards.

[JagtechOhio]

Stumled across this bit of history that has a little relevance:

Paul's [John Paul Jr.] ride in '90 was an ex-Kraco/Galles machine that wasn't repainted until after qualifications. Until then it still had it's original Kraco gold with blue and red stripes on a large parts of the bodywork. It was purchased after practice started and spent most of its time in surgery while the crew worked to custom rig the chassis to house a Buick V-6 where a V-8 was supposed to go. It only hit the track right before the second weekend of time trials. Paul put her in the show on Bubble Day on the car's third strike (back when you only got three chances) and with about as many laps left on the motor as it had before it was going to blow.

[JagtechOhio]

This from Facebook today:

Swift Engineering commented on your wall post:

"Right now we've designed around the engine configuration that the IRL is leaning towards (which they will announce when ready) but we'll be able to accommodate whichever engine configuration that is chosen. Sorry for the late reply, we had a busy week/weekend."

[bjohnsonsmith]

Originally Posted by JagtechOhio

This from Facebook today:

Swift Engineering commented on your wall post:

"Right now we've designed around the engine configuration that the IRL is leaning towards (which they will announce when ready) but we'll be able to accommodate whichever engine configuration that is chosen. Sorry for the late reply, we had a busy week/weekend."

At least someone's listening. That's promising.

[Juarez Jed]

Glad they responded to you Jagtech, even though the engine decision is not in Swift's hands.
Now let's hope there is some real discussion on the future powerplants of the category rather than just accepting what Honda want.

[JagtechOhio]

That was cool of Swift to respond, but it concerns me that "IRL is leaning towards" a decision and so is Honda, who have said they preferred a V6.

If I was a betting man, it seems as though they would be leaning in the same direction. If that means a "closed shop" with Honda simply supplying everyone with V6 instead of V8, I don't see how that will substantially reduce cost or raise interest in the Series.

Not much to do but wait, unless Ford or GM Racing decide to answer the mail.

[bjohnsonsmith]

Originally Posted by JagtechOhio

If I was a betting man, it seems as though they would be leaning in the same direction. If that means a "closed shop" with Honda simply supplying everyone with V6 instead of V8, I don't see how that will substantially reduce cost or raise interest in the Series.

Is this Honda V6 an Ilmor engine?

[JagtechOhio]

If anybody has information on what Honda is doing, I'm all ears.

Ryan Briscoe recently made a vague reference to Honda's proposal for a new IICS engine, without details. Eric Berkman of HPD has said they preferred a V6. I assume that has nothing to do with the 1.5 V6 they once built for F1.

That's all I got.

[Purist]

The International "Design, Build, Fly" competition between various colleges and their radio-controlled aircraft was in town this past weekend. I had some time to talk with an engineer from Swift who was working with the USC team, and who I know from AIAA meetings.

I can confirm from him about Honda's engine preference, but also that Swift isn't entirely sure on things since they don't have a concrete engine spec from the ICS. We also talked about wake turbulence, the "Mushroom Buster" (at least one of the Swift engineers plays Mario Kart), and L/D aero efficiency.

This individual mentioned in particular that he thought Road America, with its high-speed corners, would be the perfect playground for the "Mushroom Buster" to show its stuff. Of course, as I mentioned, and we both had a laugh, ICS doesn't run at Elkhart Lake. According to this engineer, the Atlantic chassis seems to have about the best L/D of any recent open-wheeler (~4.0:1). And we had another chuckle about the "Mushroom Buster" and wake turbulence, because a number of the newer road courses, that aren't designed for bike and club racing, set-up overtaking based on long straights into very slow corners. Now the outbraking part can still work, but if you have nil wake turbulence, you also have a weak slipstream down the straights, which doesn't help you get tucked up behind the guy in front going into that slow corner.

We also made some jokes about the other chassis submissions, and just had a good time, whenever he wasn't tied up back with the USC team, who spent a fair amount of time disassembling their plane to try and find the culprit behind some yaw, roll, and balance issues; they were wondering whether the batteries were perhaps moving around a bit.

[bjohnsonsmith]

Originally Posted by Purist

I can confirm from him about Honda's engine preference, but also that Swift isn't entirely sure on things since they don't have a concrete engine spec from the ICS. We also talked about wake turbulence, the "Mushroom Buster" (at least one of the Swift engineers plays Mario Kart), and L/D aero efficiency.

Sounds like you had a very interesting and fun. Better than sitting here with a broken leg.

Any idea if Ilmor are designing the Honda V6?

[JagtechOhio]

To Purist:

"I can confirm from him about Honda's engine preference..."

And did this person indicate whether that was a V6?

This one needs a little 'splainin, or is it just your interpretation:

"...but if you have nil wake turbulence, you also have a weak slipstream down the straights, which doesn't help you get tucked up behind the guy in front going into that slow corner."

The lead car is poking the hole in the air, mushroom buster or not. That reduces drag on the trailing car, until you pull out to pass. Less turbulence makes it easier to get on his tail without losing stability.

[awrb]

Originally Posted by JagtechOhio

The lead car is poking the hole in the air, mushroom buster or not. That reduces drag on the trailing car, until you pull out to pass. Less turbulence makes it easier to get on his tail without losing stability.

I think the point is that if the cars are producing less drag anyway there's less difference between the car in the slipstream and the car in front, so there's less of an advantage. The car should be closer anyway though, so it shouldn't be too much of an issue.

[Purist]

The trailing car would only be meaningfully closer coming out of a faster turn. Coming out of slower turns, which are more prevalent on newer road courses than older ones, it will make little difference. Unless you get a substantially better launch out of a slow corner, the physical distance between you and the car ahead will at least triple or quadruple before you have a chance to claw it back because of the acceleration and the fact that a given time interval will result in four times the physical gap at four times the speed.

For instance, the Long Beach hairpin is roughly 30mph. If you got an equivalent launch out of the hairpin to the guy in front, and are in his slipstream, you don't start pulling back the gap until you're getting into the flat-out right-hand curve just past start/finish. By that point, the two cars are doing up to 140mph, so if you were a car length behind at apex, you're now between four and five lengths back on the straight, plus whatever the guy in front gained from getting on the power sooner, by virtue of having negotiated the corner earlier.

This is the scenario you face prior to most of the good overtaking/outbraking zones at street circuits. It's less pronounced at the road courses ICS uses, because none of them have 30-40mph corners, except for the final hairpin at Sonoma. The trouble is, at Sonoma (using the motorcycle circuit) and Barber, even though the corners leading onto the straights generally aren't as slow, the straights aren't all that long. The overtaking difficulty in those two cases is exacerbated because, with more, quicker corners and segments of the lap overall, the gearing isn't set up for the same, high acceleration rates you would have on most of the street circuits. This means, even though the speed differential on corner exit may be less, your ability to claw back the differential that does exist is reduced.

Therefore, with higher turbulence/stronger slipstream, you want slower corners, and long straights. With the Mushroom Buster, you want quicker corners leading onto long straights. Tracks like Road America and Watkins Glen still work well with lower turbulence/downforce settings, because the longest flat-out runs at those tracks are just so long. From the exit of Turn 1 at the Glen to the braking zone for the Innerloop is probably 0.7 of a mile, and perhaps slightly more given that the back straight itself (0.5mi without the chicane) is pretty flat compared with the run between Turns 1 and 4. I'm not certain if GMaps takes elevation into account when using that measure tool, but it gives the lengths for the three main stretches at Road America of 0.76mi (pit straight), 0.67mi (Moraine Sweeps down to Turn 5), and 0.73mi (exit of Carousel to Canada Corner).

And yes, Jag, Honda V6. He talked a bit about some other engines, but most of that was for Atlantics or the Nippon cars.

[JagtechOhio]

Wow, save yourself the trouble next time.

As soon as you started talking about slow speed corners, it was evident that you were making all of this stuff up. Aero doesn't get you jack below 50 or 60 MPH, even with all the downforce hung on Dallaras for street courses.

awrb is right if in fact the higher speed drag is reduced by shape of the lead car, but you can still draft on him because or the pressure reduction behind it. And if the turbulence is reduced, you can do so quie comfortably, and quite closely.

If Swift thinks it's going to be a V6, that agrees with one of the other designers and with Honda's preference. Which means Delta is out to lunch, and there isn't much sense in looking for more 4 cyl builders.

How a spec Honda V6 is a relevant and cost-effective move, that will take some 'splainin too.