A locost style track car, Car9

[horizenjob]

Sense? Oh Geez, you went there? I'm thinking and I got nothing. I have a perfectly good Formula Ford in the garage. And it's well used to boot!

This started as an attempt to improve the Locost chassis, because I always loved Sevens. Well depending on how you look at it, it's improved plenty - but it's not so close to a Seven as I was planning when I started. It is a good 10 times stiffer and just generally stronger. Also has IRS which was very rare on Sevens.

It is likely to look something like a Locost or Seven when it first runs, but I am very fond of some of the styles of roadsters about 1960. I think I may have a picture of LoLa MK1 bodywork earlier in this thread, but here is another picture of a vintage beauty. Anyone recognize this? I got a note from a gentleman the other day wondering if I would like this bodywork…

[zchris]

Is that a Devin body. I'm not good with ID'ing that gen of cars as they all look the same to me.
Chris

[horizenjob]

Yes, they do look alike. In person they probably were easier to tell apart, the picture flattens them a good bit and these were very curvy cars. It looks pretty similar to the D-Type that Steve mcQueen owned.

This is an Aston Martin DBR1. Carrol Shelby took first place at LeMans in one of these about 1958.

Chris, I spent some more time thinking about your question. It goes back to when I campaigned a street car with COM. We had just moved up from cars that you pushed with your feet and decided to start putting floors in cars. This was good because we didn't lose so much change anymore.

I raced Showrrom Stock for a few years, which was great because nothing teaches you to drive better than being on equal footing. Then I wanted more and spent most of what my car cost new for wheels, tires, suspension and engine upgrades. It was a lot faster and in fact on long straights would go fast enough to suck open the top of the door frames by several inches. Enough to put your fist through.

One day there was a guy at an event who had his Formula Ford for sale. I had no aspirations to own such a fast car at the time and loved my street car and all the work I had done on it. He said, well take it around for a couple of laps anyway. Hmm, makes me wonder did they let me do that without Nomex? Anyway that car was sold in less than 100 feet. Only 10% of thw way down the pit lane and I was completely conscious of the fact that I was in a car that actually worked! I could tell by looking at it and listening to it that it was made from stock components. No vented rotors, no aluminum hubs, just a stock motor etc. etc. My God the steering was direct though and just a touch on the brake really did something.

The revs were about 2500 in 1st gear and I was loafing at a healthy and very effortless 35 mph down the pit lane. This car was a whole 20 seconds a lap faster than my other car and that was just my first laps. I got off the track quickly so I could go pay the owner

So this project is my take at providing people a choice that gets them that type of experiance without having to go quite so far as lying down in a tank of gas. I am hoping that providing a very strong frame and using generic parts from cars that weigh 2000 pounds more will make for a fun, strong and reliable car that can run with the best and be far more economical. Over the years I have seen that sobered look on a drivers face when they realize that that particular track day just cost them many 10's of thousands of dollars. That's what happens when you roll a street car...

Car9 should be more fun to drive because it will connect with the driver better. When a light car works it just becomes an extension of the driver - there isn't time to think about driving it. Then the day becomes about driving, not about herding a couple thousand extra pounds around in circles.We'll see, I hope I get to let a few of you folks take a spin, just the way someone did for me years ago.

[horizenjob]

I'm sorry I don't update here very often. My car is a good chunk of the way thru welding the frame. Here's a picture of another one under construction on the west coast. It appears to be passing it's early driving tests with flying colors!

I'll get some better pictures soon.


OK, I pointed at the picture where it's hosted on LocostUSA and it's a nice little picture of most of the car with a driver and passenger. On this site the same picture is huge and just a tiny portion of the dash. Anyone have any advice or help? I used the "Img" bbcode...

[horizenjob]

Don't know why the previous picture was sized wrong, let's try again with a couple of pictures of my car in progress. Here's a side shot and a shot of the rear bulkhead starting to go together. I just tacked on the rearward facing hoop that goes around the fuel cell / trunk area and am fitting the rear roll bar braces, but that photo was a bit too big so I'll take another when I get a little more done on the rear. It will be time to start buying the parts to fabricate suspension from soon.

[962porsche]

cars looking good . your making so head way i see that's a good thing .

[horizenjob]

Slowly chewing away at this. I guess I am learning the hard way how to make a simple car easier to build. Anyway did some tacking of tubes that were difficult to get too and starting some finish welding also. I am not good yet at welding out of position so I am moving the frame around so I can weld on the level mostly.

You can see the lower of two rear facing hoops around the trunk and fuel cell is put in. I am working on the diagonals that go under the roll bar rear braces now. Memo to self - it seems like a good idea to gusset a butt weld and another tube with that diagonal, but it it SO hard to notch the tube because of the 10 degree angle in the butt weld... Sigh...

[horizenjob]

Geez, I was trying to look at something during welding the other day and managed to get my head stuck between those two rearward facing hoops for the trunk. Sigh...

I did some simple modeling to look at the strength of coilover mounts and tubing where the suspension is going to bolt. Are you folks interested in seeing that kind of stuff? If so, I'll keep it up, if not I won't keep going into so much detail. I use an FEA program called Grape for this.

This model has the two frame rails of 1 3/8" x .083" tubing at the top and bottom with a vertical member of 1"x2"x .065" for the front bulkhead. This picture shows a 10" piece of 1" square tubing attached 4" behind the bulkhead. This represents the coilover mount and it has a 100 lb. load on it. I could represent this a lot more exactly, but I find this type of general and simple model more useful to me because for one thing I can remember the results and apply them in other situations, it gives me a feel for the problem. So this should be the same situation as a 1000 lb. load on a 1" stub on the frame tube.

The picture below shows the resulting bending force on the stub causes a stress of 14,000 psi at the frame rail. According to the mil test reports received with this material it should be good for over 50,000 psi.

The actual plan will not involve a single stub to mount the coilover, but two to allow for double shear on the bolt. Or perhaps a piece of rectangle tube scalloped to hold the coilover. The numbers basically look good, but we would like to mount the top of the coilover outboard a little bit more than 1". So caution and a little attention to detail and making the mount strong all seem advisable. I'm doing some more modeling.

The torsion load on the upper rail was basically negligible, around 500 psi.

[horizenjob]

Posted this in the classified area too...

Before I build a motor for my car project it makes sense to get hold of a motor and transmission to make sure the final tubes in the engine compartment actually allow the motor to be in the car. If it's a motor that runs then I get to use it while I figure out exactly what parts I should get and how much motor I should try to build.

So I'm looking for a 5.0 from a Mustang, Explorer or whatever else had them. Also a T5. Advice appreciated on good sources or yards for these things.

[962porsche]

personally I like detailed info so keep it coming .
that's way to funny getting your head stuck !

[horizenjob]

The funny thing about getting stuck was how instantly I was transported back to my childhood. It wasn't that hard to get out, I think I just had to turn my head a bit.

Big thanks to Pat McMahon for lending me a T5 core, a stock SBF oil pan and taking the time to talk with me. It's really helped me figure out some fitting and I learned a bunch too. Like I can't bash in the front driver's side corner of the oil pan to fit it - because that's where the oil pump lives! So the motor may move right an inch in the chassis. It's looking like things will fit though.

Pat, here's a link to an oil pan that comes in 6.5" and 7.5" deep. It stock width with no hump in the middle. That would work for my frame because I don't have any tubing under the motor or transmission. I don't know about Factory Five Cobra though. http://aviaid.com/shopsite_sc/store/htm ... f-ss3.html

Working on the third iteration of a mount for the rear of my diff today. Got some advice from a friend not to build the frame to match the cover, but instead build the frame to mount a plate which can then match the cover. It makes sense, the mount will be less in the way for installing and removing the diff. It will also work better not to have to have the frame match the center to center distance on the diff so perfectly. I was afariad I would weld it up and the first time I unbolted it, I would have a problem getting it back due to welding distortion. That was also maybe going to put a load on the diff cover. This way I can change my mind about the height and offset of the diff and also even change to a different model just by playing with the mounting plate.

Here's what the parts look like in the frame. You can almost image a motor in there.

[McMahonRacing]

If memory serves this is the pan on the older motor in the shop:

http://www.champpans.com/products/p/cp302lt-rr/

Their dwg. says 7" deep ?? Avaid, looks like a nice pan but would rather see inside it more than they have posted. I like to have some volume left & right to help open the trap doors in a turn, I know theirs is "centered" but would be nice to see .... volume is a bit low compared to the Canton ( 8" deep ) .... they also seem to move the dip stick provision to the block w/ a 3/8 fitting, so I guess you must need to modify the block at some point .... also the Canton - definately if you order the right pan & Champ ? have an additional 1/2" npt port we typically use for a temp sensor.

Me, for the cost I think I would stick w/ Canton or Moroso ..... mostly cause I am holding out for a Dry Sump at some point.

As a side note, the engine trans. in my FFR is off to the right 1.5" and so is my Dad's Healy .... we needed the room for pedals and big feet esp. in the FFR w/ a 90" WB, the Healy is a bit better @ 102" but with a narrow body it still got tight.

[horizenjob]

Pat that sump would be a good choice for my car at 7 inches. That's about how low I can put the motor without notching the frame at the cross tube under the dash. It might make sense to do that anyway, the motor is a good bit forward of where a Cobra has it. I was wondering about the weight balance, but I think it works out because the rear wheels are also forward of a Cobra setup. I should have looked at that more carefully on your car.

The Aviaid sums are a bit expensive, but they appear well made. They offer a lot of options for sizes and shapes for their pans, so I think that adds to the price a bit, t would cost a lot more to develop and stock so many, there must be 20 versions... THe ones I liked had a flat bottom front to back without a kickout at the front. THe baffling is the standard diamond shape with the pan also divided in half lengthwise and also a top plate that bolts on. You can see it in this picture.

[horizenjob]

I redid the work from a couple years ago on the mechanical modeling of Car9. Things tend to drift over time and with actual reality so this was an attempt to get things to line up again. Also I was watching my kids basketball game and each part of the team only plays half the time.

This time thru I know the software better and I am not starting from a blank sheet so I am trying to include more stuff. So the suspension, motor mount area and diff mounts are going to be checked. This work is a lot of fun to do. It seems counter intuitive to me that sometimes you can have a highly stressed tube and it does very little for the stiffness of the car, and others times you can make a little change which doesn't affect the stress much but makes the car %50 stiffer. So it's like herding cats and there are more goals than I expected. It's good to reduce stress and stiffness, but sometimes it's two different problems.

Here's 2 pictures, one shows the axial stress on the tubes, tension and compression. The next picture shows one of the bending stresses on tubes. The interesting thing here is that it shows a high stress on the tubes by the back of the transmission in the dash. It's the highest stress in the car. I'm not sure it's real yet and removing the tubes doesn't really affect the stiffness much.

In this model the dash has an inner hoop and an outer hoop to make a bulkhead. They are connected by little tubes because the program I use for this only models shapes like tubes not random sheetmetal. I will probably use mostly sheetmetal in the real car for this. So there is a chance I don't have something right there.

edit:

Forgot to say the stiffness numbers are looking good. it's something like 8000+ foot-lbs / degree in these pictures and around 12,000 ft.-lbs. /degree with a simple removable bar across the passenger seat. The pictures are showing a 4300 ft./lb. torque being applied to the frame and it is deflecting about 0.17" at the rear coilover mount area.

This is actually probably a good amount stiffer than it needs to be for this weight car. It seems very strong. Next will be checking of suspension loads etc.

[horizenjob]

Car9 is starting to feel more motorvated now, thank-you Pat McMahon!