F-1000 Rear Diffusers

[R. Pare]

Steve,


What is a sidepod anyway? Or is this one of those "we'll know it when we see it" kind of things? I'm surprise and shocked, frankly, that Richard hasn't taken up this issue, since it's a glaring one that's been staring everybody in the face for 40+ years.

Cheers,
Rennie

Rennie:

Don't think for a minute that I haven't considered bringing it up! While it would be fun to see the reactions, do you honestly think that it would be worth starting that sort of debate when guys can't even understand some of the other, more critical and obvious, rules discrepancies, such as "ground effects", Venturi", "as raced", and "from - to" ?

What, by the way, is a "nose"?

If I design an FC correctly so that it actually produces all of its downforce from the body configuration, and therefore satisfy the "airfoils" requirement as airfoils are defined, can I run without wings?

In FF it only states that such-and-such a flywheel "can" be used. Does this mean that I can use NO flywheel? How about no ring gear?

Also, no where do I see a requirement that only ONE engine is used in some of these classes.........

Naaa.... I'll stick with the stuff that has a real chance of being understood, thank you !

[carnut169]

My suggestion: FORGET IT! You ain't gonna come up with anything that won't make most cars illegal as they currently sit, and FORCING a major body reshaping on converted cars goes directly against what this class is supposedly all about, and heaven forbid that the Gloria and Speads could be forced to change their designs to fit our rules.

Forget about what?


I suppose us home-built guys can always adopt (copy) the ideas that folks more clever (Lee, Matt, you guys) come up with-

[S Lathrop]

Sean O;

Your car is what I think the rules should require. The side pod and the undertray are even at the forward edge. The undertray is no wider than the side pod. The side pod has a vertical face of at least 20 cm. Your maximum body width sets the maximum undertray width.

If that were the rule, the Stohr would have to extend the side pod out or narrow the undertray. The interplay of potential drag and down force might better equalize the performance of your car and his car. I think a mostly smooth side such as your car has or some thing like Matt proposed is the safest option and should be the rule.

The rules intend that FC be converted and run in this class. It seems that the rules writers need to think about cutting the FC cars some little brake.

Rennie;
I have spent most of my car building career in FV, FSV, FF, and FC. Those rules are much tighter than DSR/CSR. I think history will show that the tighter rules have been more successful. The loosey-goosey rules classes have no way produced the success of any of the above mentioned classes.

Competitors who buy into this class are going to want some assurance that what they buy will be competitive for several years. A 5 year life cycle seems to be the minimum, longer would be better. A cost/performance escalation like DSR has had might spell the death of this class.

I would like to see this class with 30 car grids average for a national race. It would be in everyones interest that those 30 competitors were not siphoned from other SCCA formula car classes. I would like to see this class become a real alternative to the various spec. classes and series. So should SCCA.

I think that the classes I listed had the right balance between stability and evolutionary development. Maybe you idea of formula libra is better, but history suggest to me that it is not.

[Art Smith]

while it's true the heritage FC rules include undefined terms like
"diffuser" and "venturi tunnel", it's also true that key provisions of
the heritage safety rules were not included in the current F-1000
draft. rules packages act like teams and it's my believe that
the key provisions of the heritage safey rules package not included
in the current F-1000 draft rules shielded some of the most
offensive undefined heritage terms from the bright lights and public
ridicule they so richly deserve. specificly, the heritage rule
requiring a stress bearing undertray from the front bulkhead to the
plane of the main roll hoop in combination with the heritage flat
bottom rule is most likely the reason the heritage language
wasn't the absolutely unacceptable problem it is in the F-1000 draft.

the 16+ inches from the rear of the front tire to the front bulkhead
(assuming the front bulkhead is coincident with the forward edge
of the front wheel) is an extremely effect deterent to compliant
flat bottom aerodynamic development. for equal flat thoat length,
the heritage rules force the center of pressure 16+ inches further
forward; for the same rear throat break point, the heritage rules
force a 16+ inch longer flat throat and severely limits the achievable
expansion at the forward edge of the rear tire. 16+ inches of longer
required flat bottom also significantly increases the difficulty of
controling / limiting / dealing with lateral flow under the car. see
the enclosed figure for a graphic representation of the geometry.

it's my sense that compliant (with the current draft) flat bottom
aerodynamic designs that are not level will not be very efficient
in absolute terms. aerodynamic efficency isn't a requirement at
the expected horsepower to weight ratios the current draft
severely restricts the solution space for both limitting lateral flow
under the car and for developing efficient converging geometry in
front of compliant flat bottoms. that said, there is no doubt in
my mind that a compliant flat bottom (not level) with with a crude
convergant section in front and no lateral flow control out performs
any and all compliant flat and level solutions! see enclosed figure
comparing Ralt tunnel coordinates to a quick and dirty compliant
flat bottom solution at a ride height of 1" and 2"........................

a person's character, a person's effort, and a person's results are
three very different things. most of the time I appreciate effort;
I always value results. a person's character should only be
considered if it's standing in the way of results. like the vast
majority of consumers, I purchase quality results at the
price/performance point needed for whatever I'm doing; I do not buy
anything based on the supplier's effort! a draft F-1000 rules
package with key terms undefined is unacceptable to me and a
growing number of other interested suppliers/competitors. define the
terms, use one of the already provided solutions, or get some
professional help defining the terms. anything short of a F-1000 rules
package with all the terms defined (objectively verifiable) is unacceptable.
if the terms aren't defined or a compelling explanation of why the
F-1000 community should be forced to deal with "gate keepers" forever
in lieu of definitions isn't provided, the quest for explanations is almost
certain to get sorted.


Art
artesmith@earthlink.net

[Rennie Clayton]

Steve,

Please don't misunderstand me. I have a great deal of respect for what FV, FSV, FF and FC have been able to accomplish as classes over the years. I would humbly submit, however, that if people wanted more of the same, they would be doing just that instead of flocking away from them in droves.

To abuse a phrase, F1000 is a cry for help. We don't want to be stuck with antiquated drivetrains and brakes. We want to incorporate some of the modern advances that have been spearheaded by F1 and technology in general for the past 40 years. We want new designs. We want fresh ideas. The classes you speak of, while highly successful in their day, cannot provide those things in their current guise, and competitors in those classes have proven flat out unwilling to change that guise.

Make no mistake: unless this class is clamped down to semi-spec, there will be a rat race for at least several years at the outset wherein manufacturers will leap-frog one another and obsolete each other's cars. This is just the way it's going to be until a point of maturity in design is reached when most everybody has figured out the ideal basic configuration that will work best with this HP, torque and weight regime. We can speculate all we want to about what the performance levels will be, but the bottom line is that we won't actually know for sure until some bloke comes along and does it.

I'm sure you're aware that this is the same basic situation that existed in those other classes you speak of. If I am not mistaken, early on there was a span of 10+ years in FF where each year would usher in a revolutionary leap forward in performance, instantly obsoleting cars just a year old, until we hit a cash ceiling in the performance of the cars and competitors had to start forking out metric assloads of money just to get another tenth. If you look closely at the participation history of the classes, I suspect that you will find some correlation between reaching that point, and the start of the decline of the class. Yes, the class still has good numbers at that point, but the inexorable decline has begun. It is time for another new class which is immature in its development cycle that can thrive and blossom for the next 10-15 years while competitors figure it all out, then it too will die slowly unless that equilibrium is thrown out of sorts again, allowing the competitors leeway to make their revolutionary leaps.


Art,

You keep posting those drawings, but they are well and truly red herrings. You know as well as I do that the overlay between your F1000 undertray solutions and the Ralt tunnel profile are not lined up correctly: the Ralt tunnel profile you used should end approximately 6" aft of the rear axle centreline, but you have lined them up at the same point your F1000 solutions end, at the front edge of the rear tyre. Line them up correctly, and you will see very clearly that the Cp migration of your F1000 solution is so far forward as to make such a car massively unbalanced, at best. Why not line it all up correctly, then overlay it with a raked flat-bottom with diffusor car so we can a truly accurate picture of what we're talking about?

Recently, you offered me some sage advice via email; hypocrisy does not suit you.

FWIW, though, if a manufacturer thinks they will gain an advantage by raising their Cg by 5" at the rear, and having a single Cp at 20-30% of wheelbase, then by all means have at it. I applaud their ingenuity, initiative and imagination, for whatever that gets them.


Cheers,
Rennie

[Art Smith]

enclosures to my recent posts that others refer to as "drawings and/or red herrings" have been called only figures by their author. it is hard to imagine an objective reader concluding an illustration clearly labeled as "5 minutes of thought and no testing" is something being put forward as a 'solution'. the figures were drawn to illustrate the very fundamental differences between the geometry permitted by the heritage rules and the latest draft of the F-1000 rules.

the figures underscore the need to get all of the terms used in the latest draft of the F-1000 rules defined in an objectively verifiable manner; apparently something the proprietor of the fish market would prefer to ignore. the current empassioned dialog about sidepods (just one of many undefined terms still in the latest draft of the F-1000 rulese), intent, safety, and "my car ought to be legal" is but the tip of the iceberg that will exist if all of the terms in the current draft of the F-1000 are not defined in an internally consistent and objectively verifiable manner.

if the terms aren't defined, the F-1000 community will be left with a succession of "gatekeepers" and an environment where objectivety, fairness, and motives are always in question!! definitions, like the truth, shall set the F-1000 community free................


Art
artesmith@earthlink.net

[Rick Kirchner]

unless this class is clamped down to semi-spec, there will be a rat race for at least several years at the outset wherein manufacturers will leap-frog one another and obsolete each other's cars.

Unlikely, IMHO. All of the existing classes began before easy access to CAD/CAM, rapid prototyping, affordable CFD, and on-board data acquisition. Depending on how much money a manufacturer wants to spend in the process, I'd expect designs to optimize VERY quickly.

[R. Pare]

Forget about what?

Sean:

I appreciate that your reply is tongue-in-cheek, and not meant to elicit a reply, but I'll take this opportunity to outline the problem hopefully somewhat clearer.

If the rules call for the undertray to be no wider than the sidepod skin, even if the requirement is limited to a specified minimum longitudinal length, most of the new cars are already non-compliant.

If the rules call for the undertray to be no more than XX inches wider than the sidepod skins, even if the requirement is limited to a specified minimum longitudinal length, most of the new cars and many cars eligible for conversion are already non-compliant.

If the rules call for there to be no "sharp edges capable of cutting interlocking tires", you will have to define what constitutes a "sharp edge capable of cutting interlocking tires". I doubt that that it possible in a manner that everyone will agree to and not at the same time make some car(s) non-compliant.

If you don't specify that the undertray be a maximum width, OR that it is to be considered part of the bodywork, it is then legal to make it the same as the maximum overall width, with the sidepods as narrow as the designer wants.

AND, in any of the above cases, the affected area of the undertray needs to be described - it seems that so far everyone is assuming that the affected area is only the area between the tire edges, yet that isn't stated anywhere, or even discussed, leaving the actual affected area to be the full length of the car unless stated otherwise.

The above are only a few of the problems you face as rules-writers, and you aren't going to satisfy everyone. For the designers wanting to exploit everything they can think of aero-wise, they are of paramount importance for a car designed like the traditional "flat-bottomed" FCs, and of even greater importance to those wishing to explore a raised-nose design.

Personally, I can't at the moment think of any way to satisfy all parties with all their conflicting wishes. At this point, my advise would be to leave the issue lie dormant until we see what comes of it. While some designers might want to try utilizing a wide undertray and narrow sidepods, my bet is that the majority will keep the "shelf" that is formed to something reasonable.

At the most, to address the concern that tires might be able to climb up onto the top of an exposed undertray "shelf", you might look at making sure that the exposed area where that might be possible be of a construction that insures that it breaks somewhat easily - you might specify something along the line that the outer edge of the undertay that sticks out past the bodywork be constructed of nothing more than 'glass and honeycomb or foam core, with a minimum thickness of 1/4" and a maximum of 1/2", with a blunt or rounded outer edge. Most likely, most, if not all, existing cars will pass this requirement as-is, or can be easily fixed.

Are you beginning to understand now why I was so incredulous when a new car was announced that was being built to rather non-existant rules?

Depending on how much money a manufacturer wants to spend in the process, I'd expect designs to optimize VERY quickly.

Don't bet your life on that assumption! The fact is that , and this is not stated in any disrespect to anyone here, almost no one who will be involved at this level has a real understanding as to what the ultimate level can really be, and the level that is initially reached over the next 4-5 years will be artificially low. All it will take is one guy with free access to much better minds than what we have available here, to start exploiting F1 level aero sophistication that will blow the class wide open - and the current rule set WILL allow that sort of level.

[Rennie Clayton]

Rick,

What is your definition of "VERY quickly", in a world where even the massive budgets of F1 teams expect to spend 3-4 years optimising designs and factory construction methods under very stringently defined stable rules to the point where they achieve some semblance of competitiveness? DSR is doing it well nigh every year now, and that particular bubble hasn't even been scratched yet. Has Lee already created the perfect F1000 car, or is it going to take him a couple of tries to get it right?

Have to agree with Richard on this point - this class has the capability to get very hairy, very quickly. On the other hand, taken with a fresh perspective, I tend to think that the same potential exists in FC, albeit on a more limited basis, but that's just me.


Art,

I haven't any interest in splitting hairs over whether your attachments are "drawings" or "figures" - regardless, they are inaccurate and misleading. You say that "the figures were drawn to illustrate the very fundamental differences between the geometry permitted by the heritage rules and the latest draft of the F-1000 rules" - all I see is a misleading set of drawings intended to convince the viewer that you can achieve a remarkably similar undertray profile to a Ralt RT-41 within the 1" rule. Now, the fact of the matter is that if you had actually accounted for all of the geometrical ramifications, you would know that is not even close to being the case. In any case, I don't see anything resembling a comparison to the FC heritage rules - where's the flat bottom with diffusor that it should be compared to?


Cheers,
Rennie

[Rick Kirchner]

IF someone with F1 aero experience decises to play in this class I wouldn't expect them to build a car right away. I'd expect a lot of looks at basic packaging/aero tradeoffs followed by a design that may not need a lot of work. Might take a couple of years for the car to hit the track - and in the mean time he's get to look at what a lot of the other guys were doing.

Renne - F1 rules are far from stable! Every little tweak to engine longevity, tire sets, qualification format, etc leads to a re-optimization of the aero. Yeah, the cars get quicker too, but if left to a stable set of rules I think you would see the designs plateau after a couple of years, with very minor tweaks, until a change in engine technology would bump the process again. Lather, rinse, repeat.

[Art Smith]

the first figure shows a composite of the resulting geometry from the current draft F-1000 rules, the equivalent heritage FC geometry, and a list of assumptions used in the development of the illustrations. the second figure shows five parametric solutions spanning the range from "flat & level" to "heritage FC bulkhead & a 12.5" flat throat". ALL five parametric solutions are COMPLIANT with the current draft F-1000 flat bottom rule!!! the solutions yield heights at the leading edge of the rear tires from 0.00" up to 6.98" up. if you a favorite center of pressure, I don't care. put it anywhere you want, the simple geometric relationship that flows from the +1.00"/-0.00" flat bottom rule doesn't care either.

the figures aren't the problem, the problem remains the key undefined words and phrases that are still in the latest draft of the F-1000 rules.


Art
artesmith@earthlink.net

[Rennie Clayton]

Art,

Let me be clear: showing a height of 6.98" at the leading edge of the rear tyre is not an illustration of the simple geometric relationship that flows from the +1.00/-0.00 rule. You have merely illustrated the fact that a competitor could put 7" of rake into their car. Guess what, you can tilt your FC up with 7" of rake too!!

You can tilt and skew any of the geometries to manipulate them into showing just about anything you want. But if you want to show a comparison of the geometry, then show a comparison of the geometry independent of orientation and adjustment, with the reference plane for all geometries coincident.


Cheers,
Rennie

[Art Smith]

Rennie-

open your eyes, the figure is exactly what YOU said was needed! ALL five parametric examples have a "FLAT AND LEVEL" length. ALL five parametric examples are compliant with the latest draft of the F-1000 "flat bottom" rule. if you're interested in understanding the geometry, spend a few minutes thinking about the attached figures. it's just very simple descriptive geometry, not close to rocket science...............................


Art
artesmith@earthlink.net

[Rennie Clayton]

Art,

What I said was needed was a comparison with the reference plane for all geometries coincident. What you have posted is most emphatically not that. You have "five parametric examples" in your post above, which utilize 4 different reference planes. Again, you have only illustrated that cars can have rake, which is in no way a revalation. By mixing in orientation to your illustrations, you have not created a like comparison of physical geometries.

Your illustrations attempt to lead the viewer into drawing the conclusion that the physical geometry of the undertray can result in a 7" deep "tunnel" exit at the rear of the car. Given that you have a +1.00/-0.00 tolerance, you cannot do so without at least 6" of rake in the car - which means that it's not a result of physical geometry. It's a result of ridiculous car orientation that would result in the lower a-arm pickup points on the chassis being located at approximately the same height above ground as the wheel spindle.


Cheers,
Rennie

[R. Pare]

Art:

Seems I must have missed something here: Just when and how did the term(s) "flat" and/or "horizontal" creep in here?

The use of the term 'horizontal" in reference to ride height (rake) is a setup parameter, NOT a design parameter, and the Club has ZERO right to any access to setup information for these classes. I already squashed that thought by a CRB member years ago when he insisted that "horizontal" had to be in reference to the horizon, with my retort being "just what happens then when the car is going uphill or downhill?" - measuring the cars' rake to determine compliance of the bottom shaping was quickly dropped thereafter!

Kinda makes you realise that there may be a valid and already agreed-to-by-the-CRB basis for my "as raced" wording contentions?

[Art Smith]

Rennie-

friends are expressing concern about me "wrestling with a pig in public" so this will be my final attempt.

Your illustrations attempt to lead the viewer into drawing the conclusion that the physical geometry of the undertray can result in a 7" deep "tunnel" exit at the rear of the car.

I am not attempting to do anything, I am stating as a fact that the height of the diffuser opening at the front of the rear tires can be made anything between 0.00" and 6.98" (undefined for the ridulous case of simple chassis rake) above the selected ground clearance with a flat bottom compliant with the latest draft of the F-1000 rules! the descriptive geometry construction is provided, the five parametric cases are shown schematicly, and a composite of the five cases depicted to scale on the same wheelbase and same ground clearance is also shown (apples to apples to apples to apples to apples). the "reference plane" (for verifiaction of compliance) for the top three parametric cases can be thought of as the inclined lines representing the bottom surface of the car in the figure below; the "reference plane" for the two simple cases should be thought of as the right side of the cases or the ground clearance line; they're coincident. it would be misleading to show the five cases in any other orientation than what would be seen at the track with cars with the same wheelbase and ground clearance.

Given that you have a +1.00/-0.00 tolerance, you cannot do so without at least 6" of rake in the car - which means that it's not a result of physical geometry.

ALL five parametric cases shown have a portion of the compliant "flat bottom" of the car that is PARALLEL to the ground/track. there's more going on than simply inclining/raking the bottom of the car!!

Again, you have only illustrated that cars can have rake, which is in no way a revalation.

It's a result of ridiculous car orientation that would result in the lower a-arm pickup points on the chassis being located at approximately the same height above ground as the wheel spindle.

I've made no claims of "revalation", haven't said any or all of the potentially compliant flat bottom geometries yields competitive advantage(s), or that it was my intent to employ any or all of the ideas presented here. what I have called for repeatedly over the last several months is objectively verifiable F-1000 rules with all of the terms defined!!!


Art
artesmith@earthlink.net


ps: unless you're reverting to Crossle 32F like rear uprights with the lower outboard pick-up points outside of the wheels, the centerline of your lower outboard ball joint is probably someplace between 4" and 6" up from the ground ((22" -13")/2.) gets approximate loaded tire section). assuming a small reduction in the diffuser entrance height at the front of the rear tire (from theoretical) for manufacturing tolerances, I'm guessing finding rear inboard pick-up points that yield the kinematic roll center and camber control over the required range of bump, droop, and roll to be fairly straight forward for even the most extreme of the presented geometries............................

[R. Pare]

Art:

I'll ask once again: When, how, and where did the use of the term(s) "flat" and/or "level" creep in here?

Actually, it doesn't matter as to the when/where/how - I think that you are missing the gist here.

Even IF the terms flat and/or level are used ( and THAT is a horrible idea), the bottom of the car still has a reference plane that it HAS TO COMPLY TO within the described area, no matter what - meaning that the maximum that any portion of the undersides in the controlled area can deviate is 1.0" UPWARDS & perpendicular to the plane described by that reference surface.

That means that even if you tilt the reference plane so that it is higher in the back than the front, the remainder of the undersides in the controlled area cannot be below that plane ANYWHERE.

The ONLY way you can achieve that sort of high throat at the rear of the controlled area is by rake, and there is then NO WAY any major portion could be "level". Tiny portions, yes, but they would still have to stay within that 1.0" restriction in the described area. "Flat"? Yes, for sure again - the whole undersides or any portion thereof can be "flat" (with "flat" meaning "in a single plane"), as long again as it stays within that 1.0" restriction in the described area.

And, quite frankly, while the height of the diffuser exit somewhere BEHIND the controlled area CAN come out to some of the dimensions you've illustrated, who and/or why should anyone care?

[ex-racer]

All this debate and talk over rear defusers....How about NO UNDER CAR AERODYNAMICS. Flat bottom means flat bottom. The only downforce is to come from the body work and wings.

[mtmansl]

+1 I agree completely!! Why would you even want a diffuser? The cars will have plenty of grip for the power they will have, and besides, do you really want to be replacing these things every time you run over a curb, or off the track?????

Matthew

All this debate and talk over rear defusers....How about NO UNDER CAR AERODYNAMICS. Flat bottom means flat bottom. The only downforce is to come from the body work and wings.

[RussMcB]

Keep in mind that the origin of the F1000 class is converted FC cars, and almost all of them have diffusers (I think).

+1 I agree completely!! Why would you even want a diffuser? The cars will have plenty of grip for the power they will have, and besides, do you really want to be replacing these things every time you run over a curb, or off the track?????

Matthew

[ex-racer]

Keep in mind that the origin of the F1000 class is converted FC cars, and almost all of them have diffusers (I think).

While that may be true, most of the ones I have ever seen are a seprate piece of fiber glass that ataches to the undertray of the car so it would not be a big deal to have them removed. This would do 2 things. Eliminate the need to replace another pice of the car should someone go off the road and also level the playing field even more. They have their place, but in a new class looking to control costs replacement pieces should be considered.......

[Dave Belz]

... but in a new class looking to control costs replacement pieces should be considered.......

I'm more grateful for the efforts being made to control burning up the cost of a new diffuser in fuel every weekend. "Reasonable" cost is more on target than "controlled". Another goal is to permit at least some components and technology less than 40 years old.

More seriously, an FSCCA is a 'newer' class with sequential shifters and without diffusers. Why have F1000 at all then?

Dave

[Mark Beckman]

More seriously, an FSCCA is a 'newer' class with sequential shifters and without diffusers. Why have F1000 at all then?

Dave

My retort is why does the FSCCA have to be such hi tech, hi price when its a spec racer only competing agaisnt itself. What were they thinking? If they had done it right (affordable) and used bike power units in the first place to get there 145hp and sequential gearbox, F1000 probably wouldnt exist.

Anyway, this is now, maybe you wont win but you can be competitive and have some great fun for less than 10,000 (my estimate) in F1000 in your own home built, even less depending on your skill and workload.

[Mark Beckman]

Im sorry I came late to the party, diffusers are a pain and not required for this class it just gives the knowledgable and wallets an advantage.

Flat bottom all the way to the rear wheel rear edges and from there a verticle plate say 200mm high x 500mm wide to promote a hole in the air for slipstreaming and passing.

[mtmansl]

SCCA Enterprises really screwed that whole thing up!! $50,000 and they play it off as an affordable class? The car was suppossed to have a mc engine in the first place, but they had to get fancy. The cost of replacement parts is way out of line as well. I hope that plenty of thought is given to keep this class(F1000) affordable, and it will take off. In my opinion $30,000 is starting to creep up there for the cost of a car!

Matthew

My retort is why does the FSCCA have to be such hi tech, hi price when its a spec racer only competing agaisnt itself. What were they thinking? If they had done it right (affordable) and used bike power units in the first place to get there 145hp and sequential gearbox, F1000 probably wouldnt exist.

Anyway, this is now, maybe you wont win but you can be competitive and have some great fun for less than 10,000 (my estimate) in F1000 in your own home built, even less depending on your skill and workload.

[mtmansl]

You also have to keep in mind that most FC cars are modified 1600s, which were never designed with a diffuser. Flat bottom is the way to go!

Matthew

Keep in mind that the origin of the F1000 class is converted FC cars, and almost all of them have diffusers (I think).

[RobLav]

In the F1000 rules committee, we discussed the possibilities of these cars with various sized motorcycle engines. One of those possibilities was using a 600cc engine in a formula ford type chassis with no wings nor diffusor. It sounds like that is where you are heading.

We saw Tier 1 as 1300cc engines in carbon tub chassis with lots of aero.

Tier 2 as F1000 with tube frame and some aero

Tier 3 as F600 with tube frame and little to no aero

Put yourselves together a F600 rules committee and make it happen.

[mtmansl]

I don't think I ever mentioned a ff with a 600 cc motor anywhere??? That was not where I was going. Rather, F1000 and keeping the costs down. Are you done with the smart@ss comments?

Matthew

In the F1000 rules committee, we discussed thepossibilities of these cars with various sized motorcycle engines. One of those possibilities was using a 600cc engine in a formula ford type chassis with no wings nor diffusor. It sounds like that is where you are heading.

We saw Tier 1 as 1300cc engines in carbon tub chassis with lots of aero.

Tier 2 as F1000 with tube frame and some aero

Tier 3 as F600 with tube frame and little to no aero

Put yourselves together a F600 rules committee and make it happen.

[Rennie Clayton]

Im sorry I came late to the party, diffusers are a pain and not required for this class it just gives the knowledgable and wallets an advantage.

Flat bottom all the way to the rear wheel rear edges and from there a verticle plate say 200mm high x 500mm wide to promote a hole in the air for slipstreaming and passing.

Luckily for you, the rules allow just this sort of undertray arrangement! You'll have to patiently explain to me, however, how building your contraption at the back end of the car is somehow less of a pain than a diffusor. I'm sure you'll have an answer. Anyway, build yours that way and have a ball.

With regard to the first paragraph: the knowledgeable will always have an advantage, and wallets can be overcome.


Cheers,
Rennie

[RobLav]

Matthew,

I do take slight offense at your insinuation that my comments were "smart@ss". My comments remain and are entirely serious.

Do you race a formula car in SCCA? or do you intend to?

We are happy to help new people here, but for a guy with 6 posts and that attitude... well... the odds of me helping you now in any way are slim. Perhaps others will.

[Mike B]

Matthew,
I saw nothing smarta$$ about Rob's comments. He was merely stating how we came to point we're at now. We've been discussing F1000 and it's underbody rules ad nauseum for almost a year now and we're all now in agreement that diffusers will be a part of F1000. In fact, it was never in question (to the committee, anyway). It's just a matter of wording it so people don't exploit it to the extent they have in FC (not ).
I know there is a lot of stuff here, but I politely suggest you read through the many posts regarding the aero rules and F1000 in general. It might give you a better feel for the impetus and philosophy of the class.

[Mark Beckman]

Luckily for you, the rules allow just this sort of undertray arrangement! You'll have to patiently explain to me, however, how building your contraption at the back end of the car is somehow less of a pain than a diffusor. I'm sure you'll have an answer. Anyway, build yours that way and have a ball.

With regard to the first paragraph: the knowledgeable will always have an advantage, and wallets can be overcome.


Cheers,
Rennie

The contraption at the back end is a flat plate leading to a 90 degree bend compared to a carefully designed contour crafted around clever a arm design placement requiring special uprights etc.

Now you tell me why diffusers are required at all?

My knowledgeable comment refered to those in the know about aero's, a specialised subject.

[Rennie Clayton]

Mark,

I knew you would have an answer! And yet, it doesn't really answer my question directly about why that is less of a pain, because you've casually ignored the fact that any competent designer is going to carefully design a body contour crafted around clever mechanical component packaging requiring specialized mounting hardware and aerodynamic design in order to overcome that big parachute back there. What I'm saying is that your suggestion is not the free lunch you represent it to be.

Speaking of "restrictor plates", as an aside to the greater F1000 community concerned about engine parity: why not use a fuel restrictor instead of an air restrictor to limit horsepower? Think about it...

As you are the late arrival traipsing into the party with a few "friendly" suggestions for how to make improvements to the class, I submit to you that it's incumbent upon you to convince the establishment, not the other way 'round. As with any other situation in life, if your intention is to stray significantly from an established vision, then you are going to have to make a damned better case than "because I think it will improve things." Your cars will already have a sizeable price point advantage over other manufacturers, however, so I have to wonder: as these suggestions will not make one whit of difference to the selling price of your cars, and as such the joys and agonies of automobile racing will thus supposedly be rendered available to the great masses at reasonably low cost, what motivation do you have for seeing this rule change enacted other than to hobble the performance of other cars in order to make yours more competitive?

Did your knowledgeable comment also extend to:

Metal fabrication
Composite fabrication
Mechanical drafting and design
Materials engineering
Rubber chemistry
Lubricants chemistry
Fuel chemistry
Thermodynamics
Meteorology
Damping theory
Physics theory
Suspension geometry
Internal combustion engine design
Electronics and computer programming
Physical fitness
Mental preparation

Or aerodynamics just that one facet of fast race cars which you have decided to focus upon?


Cheers,
Rennie

[Dave Belz]

...the knowledgeable will always have an advantage, and wallets can be overcome.

Rennie,

Can I use that line in my signature?

Dave

[RobLav]

Hey Rennie - that was a really good post.

[mtmansl]

Rob,

Just to back up my "credentials" to you because I am such a noob! I started racing a formula car in SCCA in 1989 after years of karting. I have also raced in ACRL, Firehawk, IT, FV, S2000 and several other classes. I was also a mechanic for North Shore Racing and Stuart Moore Racing in Pro Atlantic, and Indy Lites. In fact there are several of my former ff1600's and ff2000's for sale on this very site right now. Are my credentials good enough to offer an opinion??? Do they meet your standards, because it seems the most important factor to you is that I only have 6 posts. I simply made a statement of how diffusers were an item that was probably not needed on a car with this ammount of power, and how it was also an added expense when cost cutting is one of the main goals. By the way, I don't really think that I asked for, or that I need your help! Your arrogance is misguided!

Matthew

Matthew,

I do take slight offense at your insinuation that my comments were "smart@ss". My comments remain and are entirely serious.

Do you race a formula car in SCCA? or do you intend to?

We are happy to help new people here, but for a guy with 6 posts and that attitude... well... the odds of me helping you now in any way are slim. Perhaps others will.

[RobLav]

Whatever Matthew... take your issues up with the CRB then.

[mtmansl]

Really,

The only issue I have is your condecending attitude! You took a suggestion as a personal affront, and assumed, because I had only 6 posts that I wasn't qualified to give one. That's too bad, because I was not trying to start anything!


Matthew

Whatever Matthew... take your issues up with the CRB then.

[ex-racer]

Having raced FA and F2000 cars for over 15 years I see no reason a defuser is needed on such a low horsepowered vehicle. From everything i have read this was supposed to be a " Cost Effective " class. For those of us who have cracked them or have them driven into while being followed too close, know that they cost money to replace. Just seems to me that in a cost effective class that something that would be a luxury would help keep overall cost down.....

[VehDyn]

Just out of curiosity, what kind of hp is considered low hp to not require a diffuser. I've seen that menioned a couple times in this thread.

Thanks.

Ken