Novak conversion takes shape

[Bill Maisey]

Here are a picture of the sub frame on the fixture. It is about 80% complete. Final welding this weekend or early next week. We will have it on the chassis early next week with the engine fitted by the end of the week.

For more, visit Jay's website:
http://www.novaracecars.com/fab.htm

[andyllc]

Looking at this picture makes me wonder (not good late at night on a Friday)

I see round tubing used for a chassis, also square tubing. Which is stronger? Why one versus the other? Also, this will sound odd but would triangular tubing work as well? I feel it would be strong than square tubing but I really dont know and would be interested in learning.

[RussMcB]

Andy, I slept at a Holiday Inn Express last night, so I'll take a stab (even though there are much more knowledgeable folks around).

For the same weight, round tubing is a little stronger than square tubing.

For my current F1000 conversion project, I'm using mostly square tubing, because there are a lot of places where I need or want a flat surface.

If you do a search, you'll see this has been discussed in here recently.

I don't know about triangular tubing.

[S Lathrop]

1. The weight to strengeh is a lot different when you add up the total number of feet involved.

2. It is much easier to mitter and weld round than square, especially when you have out of plane intersections.

3. Square can be dificult to attach simple brackets to and not have problems with cracking when the bracket is welded some where than on the edge.

4. Joint cracking can be worse with square because of the way the loads transfer from one tube to the other.

This is just my opinion.

[andyllc]

Cool Thanks for the info guys

[jgaither]

Andy:

I'll make sure that you and Richard get a round-tubing kart on Monday night.

jg

[formulasuper]

Looking at this picture makes me wonder (not good late at night on a Friday)

I see round tubing used for a chassis, also square tubing. Which is stronger? Why one versus the other? Also, this will sound odd but would triangular tubing work as well? I feel it would be strong than square tubing but I really dont know and would be interested in learning.

Triangular tubing? Do you have a picture?

[LJennings]

If we have a 1" square tube x .062 wall and compared it to a 1" round tube x .062 wall the square tube will be stronger.

It's all about the Momemt of Interia. The farther away the material is from the neutral axis the hight the MI.

You have to be careful when you use strength to weight. Aluminum (45 ksi tensile to 1/3 weight of ateel) has the strength to weight higher than steel (85 ksi tensile (cr)). So to build a structure out of aluminum that will take the same load as a steel structure the section thickness would need to be aleast doubled.

It all goes back to sound engineering and identifing the load paths and selecting the correct material to handle the load.

[WRD]

If we have a 1" square tube x .062 wall and compared it to a 1" round tube x .062 wall the square tube will be stronger.

It's all about the Momemt of Interia. The farther away the material is from the neutral axis the hight the MI.

This is true depending on where the neutral axis of the bending is. A square tube will have different stiffnesses depending on the orientation of the bend It is my understanding that in theory, only round tube should be used as it doesn't matter which way you load it it will always have the same stiffness in all directions, however, this is not always practical and as was mentioned above, sound engineering should be used to determine the proper tube in all instances.

[andyllc]

No I dont have a picture of the triangular tubing and dont know that it exists, doubt that it does. It was just a Friday night end of the week brain fried off the wall thought.

JG
Im going to Victory Lane Karting tonight (sorry but it is only half the distance as going to your place) to practice for Monday night. Mainly for my girlfriend to practice because she will be doing the race with us on Monday so we can see how she does. I am hoping that since she weighs half of what I do that she will be quick. Then again Richard is the size of most girls as well.

Richard was saying the pit stops were taking 30 seconds but why on earth would they take that long? I think they should be ten seconds TOPS. My races we do our driver changes in 22 to 27 seconds and that is with full belts, radio, water bottle, driver id plug, belts over the hans, window net up, everything. We will have a better strategy than last time. Basically have only 3 stops. Not necessarily equal distances apart with the drivers getting progressively faster as the race goes on and hopefully whoever is the slowest though will be able to slow the pace of the leaders to for example instead of going 5 laps down in the beginning maybe only 2 laps down. Make sense? Of course do that without blocking and getting a penalty.

We shall see, as everyone knows we can have a million plans but when the green flag drops the bull**** stops

[Wren]

Looks good. Do you have a price yet for the conversion?

[bblair77]

Any more updates? Cost info?

[Jay N]

There will be more pictures on our website later today. We bolted the subframe & the engine onto the Van Diemen chassis yesterday.

Costs will be posted next week with a complete list of all components included.

Thanks ... Jay Novak

[Jay N]

The new pictures are up on the NovaKar website:

www.novaracecars.com

Thanks ... Jay

[ianashdown]

Hi Jay,

I'm wondering if the 44.5 Lbs quoted includes the Diff assembly or not.

Thanks,

Ian

[jattus]

Jay-
The big question is how much? Please post or PM your estimated price.

[Jay N]

Ian, that is the weight of the subframe only, no diff.

The production part will be 6 lbs lighter than the prototype.

Thanks ... Jay Novak

[Jay N]

I am still working on the spreadsheet with all the parts & costs. I will be done with it next week & will post both here & on my website.

Thanks ... Jay

[GoPro]

I am still working on the spreadsheet with all the parts & costs. I will be done with it next week & will post both here & on my website.

Thanks ... Jay

I am not a mechanical engineer, but I think looking at the bicycle industry is a good place to learn about frame rigidity and strength. They are constantly searching for max rigidity out of minimal frame for weight reasons. Given that most bike frames, including hardcore downhill bikes, are round tubing...telling. Perhaps you frame engineers can learn from studying leading mt. bike frames. There's a lot of money going into frame R&D in that industry. Copy it since it's not competitve!

[Billy Wight]

I am not a mechanical engineer, but I think looking at the bicycle industry is a good place to learn about frame rigidity and strength. They are constantly searching for max rigidity out of minimal frame for weight reasons. Given that most bike frames, including hardcore downhill bikes, are round tubing...telling. Perhaps you frame engineers can learn from studying leading mt. bike frames. There's a lot of money going into frame R&D in that industry. Copy it since it's not competitve!

Round tubes have their place in certain applications and so do square tubes. In general, round tubes are preferable as they spread the material away from the neutral axis as far as possible for all loading directions and therefore also have the greatest resistance to torsional flex. Square tubes are nice for mounting certain hardpoints. The best thing to do is to determine what tradeoffs you are willing to accept and where as far as square vs. round tubing and plug everything into a beam element finite element program with proper boundary conditions. This tool can then be used to optimize tubing diameters and wall thickness to meet the stiffness and weight goals you're trying to achieve.

A properly designed bicycle frame will be stiff laterally to increase pedaling efficiency, but will be more supple longitudinally to act as a sort of suspension for the rider - this is easiest achieved with composites by varing the orientation of the fibers, but can also be acheived in metal by varying wall thickness, the tubing cross section, and using bent tubing. Take a look at most titanium road bike frames and you'll see what I mean.

Billy Wight
Luxon Engineering, LLC

[Mark H]

Looking at other race cars most have gone to round tubing. I remember when the dirt late modles went from 2+3 tubing to 2+2 that was a big breakthrough. Then I think it was Bloomquist that showed up with a round tubing car he was almost accused of cheating because of that, now every car out there is 1 1/2 round tube. But the down side is that they only get maybe a half a season out of those cars due to frame twist.

Since most major forms of auto racing have long since gone to carbon frames development of tube frame cars has stoped.And along with it any further development in different types of tubing.

[Jay N]

While tube frames may be old technology, they are still the most cost effective solution available for low cost race car chassis.

I have done extensive FEA modeling of many different chassis & it is clear that there are applications for both round & square or rectangular tubing.

A perfect example is where structural panels can legally be attached to a frame by riviting & or bonding. This is where round tube DOES NOT work well for this application. Structural bosses are also more difficult to do effectively in round tube.

Round tube is generally the most weight effective solution but both types of tube have the merits & appropriate applications.

Thanks ... Jay Novak

[Dave Harmison]

Great website, Jay. But I was a little disappoiinted. You didn't turn the engine around, or sideways, or lay it down to lower the cg, or any of the "way f'ing out of the freaking box" thinking I expect from Jay Novak. :-}

Had to say bud. Hope your enjoying "retirement".

[Jay N]

Hi Dave, yes I guess I am getting a bit conservative in my old age. But wait till you see the next project.

No time for retirement, too much race work.

Thanks ... Jay

[Bill Maisey]

New rear sub-frame is nearing completion. For more details see Jay's site www.novaracecars.com

[neildrake]

Really nice work Jay.
What year VDs will this work on?
Do all the newer VDs have bolt on rear subframes?
Do you retain all the same A-arm and pushrod lengths?
Thanks,
Neil

[neildrake]

Another couple questions for you:

Will the stock diffuser work?
Are you bonding a belly pan on the rear subframe?

Neil

[Jay N]

All the STOCK arms, push rods & rockers are used. Very careful analysis of all the various geometry has allowed me to move the bits around to solve the package problems. The resulting suspension/shock geometry is the same as the stock Van Diemen.

yes there will be a rivited & bonded belly pan on the entire rear subframe.

We will use the stock difusser to start but will do our own difusser over the winter or sooner if possible.

We are sure it will fit on all 98 & later Van Diemens. I have heard that there are some 97s with the same chassis.

We will definatley be doing a kit for earlier chassis.

Thanks ... Jay Novak

[Messenger Racing]

Jay,
Are you leaving the motor square in the chassis or are you missaligning it some to get your chain position for the rear gear? Are you running stock half shafts or are the different lengths side to side?

JM

[Jay N]

Jay, the engine & the diff are in the car on a very slight angle. This is the only way to be able to use the stock arms. This is the same solution as used in the Speads race cars with zero problems.

The car uses a stock Quaife diff. This diff is wider than the stock LD200 diff & thus the axles will not be stock length. We are looking for other CV hubs that may be shorter but have not found any yet.

In my opinion a Quaife or similar diff will be needed to run at the front because these cars will have 180 hp and be about 200 lbs lighter than an FC car. However just for fun we may try a spool & an open diff in a car next year.

The half shafts are very slightly different in length to accomodate the stock Quaife parts. The difference in axle length can be corrected with a spacer or a different hub on 1 side of the diff. Frankly the difference is to little to worry about.

The only way to use the stock half shafts is to make a special diff. Way to expensive.

Thanks ... Jay Novak

[John Mosteller]

Jay,
Is there a reason you don't like the ICP varilock chain drive diff that is the same flange to flange length as the LD200? Link below to the ICP announcement on the Sports Racer Forum.

John

http://p081.ezboard.com/fdsrforumcar...icID=796.topic

[Jay N]

No reason at all John, just not enough time to get one & design it into the package. It may actually be a better package. I have already spoken to Richard about it & will get one when the timing pressure eases a bit.

Thanks ... Jay Novak

[R. Pare]

I'm actually going to start cutting material this weekend for the new F1000 design, as soon as I finish up a few custom BMW diffs tomorrow sometime. So much for a relaxing "holiday" weekend!

[Jay N]

Richard, please call me when you get an opportunity (Saturday is best)
313-445-4047.

Thanks ... Jay Novak

[JHandley]

Jay,
What model year of the van diemens would your conversion kit cover?
Some of my 2 wheeler biker friends and I have been talking about this at work and there is a pretty good interest in the possibilities presented.

[Jay N]

This kit can be used on 98 or later Van Diemen chassis. The 1st kit is nearly done with just the finishing touches left. Pictures after the Sprints.

We plan on doing a conversion for earlier chassis if this one takes off.

Thanks ... jay novak