Adding Ballist

[Captain]

Hi,

I have to add a few pounds to my car to make weight. I have a really nice spot right under my seat that will work well. I planed on bolting several Bars of steel together so that if the drivers change (or my weight) it is very simple to add/remove a bar.

What do you think is the most minimaly invasive way to attach this weight to the car? I really don't like drilling holes in the main frame members. Bolting to to floor pan is a thought, but that will take up some of the smooth-ness.

Any ideas?

Thanks
Jim

[hardingfv32-1]

Is your selection of the location a compromise? How is the car handling? Generally easier and more helpful to mount ballast on either end of the car depending on how it handles.

Brian

[brian]

I use lead sheets under the fuel cell. Simple to install and remove and held in place by the cell and seat.

[VDF1]

I used lead shot put in reinforced bags and super-taped to the belly pan. It's sold in 25 pound bags to shotgun owners who want to make their own shells. The bags are moldable and cheap.

[Captain]

I really have nothing to compair handling to, as this is my first Vee. It is probably on the tail happy side, but I do like driving this way (always had RWD street cars).

The idea is that I can move these bars within the floor to play with weight. They were bandsawed a 1/4" narrower then the distance between the frame tubes, so they fit well. I just need a device to hold them from sliding front to back.

Thanks!
Jim

[robert]

Brian (harding)

How did your effort to move weight forward (50/50 distribution) work out?

[Frank]

you can even melt the lead shot with a MAAP gas torch to make whatever shape is needed to fit in the car.

[hardingfv32-1]

Robert

I built a new car to attempt 50/50 weight distribution. EVERYTHING moved forward. A 25 lb. steel nose cone to get weight beyond the normal 10" limit at the front. The oil cooler was moved to the nose and mounted at the 10" limit where it was unbelievably happy (1/2" X 6" duct opening got you 180 deg oil on a 70 deg day). Raised floor so the fire bottle and master cylinders could be under the drives feet. Very light 1"X .060 wall round tubing rear frame with the engine as a stressed member. I think I got to 52f/48r, it was the best I could do. Had 20 lbs. of lead ballast mounted right at the 10" front limit. Turned out the car was not happy that way and moved the 20 lbs of ballast all the way to the very rear to get it balanced. I was lucky to have the ballast to move.

On to a new aero car......

Brian

[brian]

Weight distribution shifting will work up to a point at which the tires are overloaded. Most front tires on zero roll cars are marginal to start with. You'll see a lot of cars using the short rears or wide fronts to compensate for the overloading.

[robert]

Brian H.



Will your "aero" car employ 50/50 or similar weight distribution?

When you say aero, are you meaning slippery, or will it be an attempt to gain downforce at the front in place of moving weight forward.

[hardingfv32-1]

I will use the same weight distribution as the last car. The fact that is that when the old car was dialed in, it was no better than other front runners. We had our poles, fast laps, and track records, but we did not stand above the competition in the corners. I will follow good practice but not lose sleep over compromises in this area.

The new car looks like the Vestal FF (2nd at Runoffs) but with a very round nose and chopped tail to fit the FV length restrictions. Michael Varacins car is pretty much the correct way to go at the front. Slick is NOT a pointed nose. I'm not sure that you can accomplish much after the roll hoop.

Putting a big effort into getting all the engine and oil cooling air from the front of the car. This does not increase frontal area and this is one of the few places to find high quality air flow. Engine cooling is fully ducted. Enters below the drivers feet (raised floor). Travels beside the drivers hips, enters from below the engine and exhausts out the top through chimneys into a low pressure area.

Waiting on CFD tests to develop the other details. My aerodynamicist has been very busy with his real job, even in this economy.

Brian

[VDF1]

Brian, I hope your guy, when he's back in the chips, recognizes that what he does after the roll hoop is most important because most drag is created at the trailing edge, not the leading edge--correct, no? What is the projected time for your latest creation to be on a track?

I like your idea of experimenting with weight distribution in a FV--poor weight distribution has been accepted as a given in FV for years--why? Innovation comes from challenging the status quo. Good luck in your mission.

[hardingfv32-1]

One end of a particular aero shape is not more important than another. They work together as a system. After the roll hoop plane of the car the air flow has a hard time staying attached to the body and is hard to work with. This is because of the poor air flow around the wheels, cockpit opening, etc. Air flow is actually becoming unsettled after the front beam. It is very unrealistic to expect to close up the air flow at the back of a FV. Just not enough length with the engine being the widest part of the car. A good aero shape has the widest point about 1/3 distance from the nose. Porsche did not drag those long tails around Le Mans because they made the cars easier to turn. IF you can keep the air flow attached, the tail of such a car will actually provide forward thrust. Helps negate the drag from the nose doing the initial penetration. That is why it is a system.

Making manifolds this season. The new car will be ready for next year.

Brian

[jpetillo]

Brian, well put. I completely agree. It has to work as a whole for exactly the reasons you say. John