Mid- Engine Modified Sports

[manta22]

You're welcome any time, Mike. Ditto for any other LSR guys.

Regards, Neil  Tucson, AZ

[manta22]

I flipped the chassis over (right side up) and lowered it down on wood blocks that approximate its ride height. All the Clecos are still in place, holding the bottom panel on, so I weaseled my way into the driving position and had Joline mark the center of my spine and measure the height of the tops of my shoulders. My original shoulder harness attachment points are not in the right place so I had to cut and miter two pieces of tubing (1 3/4" dia x 0.120 wall mild steel, the same as the roll cage) to add to the cage to provide attachments that meet the SCTA and HANS requirements. I've already welded on one tab, the second one will be added after the tubes are welded into the cage.

A & A Manufacturing makes a huge selection of tabs and brackets. I am using ones that are U-shaped so the belt end is in double shear as recommended.

I cut 4 pieces of 7075-T651 aluminum angle (1 1/4" x 1 1/4" x 0.095") to mount my battery box. It is a sealed polyethylene box from Speedway Motors and I'm looking at using a size 78DT battery in this box. I'd like to use a heavy nylon strap across the top to keep the box in place but I haven't found a suitable one yet; the aluminum angle will be riveted to the bottom panel and those will keep the box from sliding around in any direction.

Time to go feed the dog.

Regards, Neil  Tucson, AZ

[salt27]

Neil,
 You might want to check on the interpretation of 3.K regarding battery hold downs.

My understanding is they are to be made of metal.

  Don

[manta22]

Don;

You may be right. It says the battery must be secured with a metal framework and fasteners. To keep from causing a possible problem, I'll go with a metal hold-down... possibly one or two stainless steel straps with a tensioning latch.

Thanks for pointing that out.

Regards, Neil  Tucson, AZ

[manta22]

More welding on the chassis. I've now determined the places to attach brackets for the fire extinguisher and 'chute pull handles.

Here the chassis is sitting on two metal saw horses while being welded. This way I don't have to bend over so far but it entails crawling into the chassis.

Regards, Neil  Tucson, AZ

[tauruck]

Cool photo Neil.

Getting comfy to weld is 75% of the job.

[manta22]

Thanks to Don, who pointed out that my plan for securing my battery box didn't meet the rule book requirements-- so, plan B.

I cut a length of 16 gauge 1 1/2" x 3/4" mild steel tubing and welded a thick cap on one end. This will lay across the top of the battery box. That end cap has a 3/8" hole that matches a similar hole in the side hold-down. This piece is 0.050 6Al4V titanium with a doubler plate of 0.095" 7075-T6 riveted to the top edge. The rivets are CherryLock CR2653-4-4 which are A286 alloy. I fooled around with the rivet puller nose to see how much it changed the stem break depth so they look a little different but the stem is staked in place in all of them. The bottom edge is drilled for 3ea 1/4-28 bolts which will thread into Nutserts which I'll install into a chassis tube later.

The 3/8" holes are for stainless quick-release (pip) pins that will allow the battery box to be removed without much effort.

The zinc chromate primer is still drying on the angle that will secure the battery box laterally but I did get the holes match drilled in the bottom panel today. The Paint on the battery hold-down tube isn't dry yet either so no pictures of those pieces today.

BTW, the faint lines on the Ti sheet is a pen mark, NOT a scribed line. Never scribe layout lines on sheet metal that is going to be used in a race car or aircraft application. As Carroll Smith said, "It indicates where it will break."

Regards, Neil  Tucson, AZ

[tauruck]

Neil, that is one cool battery box lid.

Everything about it screams "pro".

I love the way you work.

I have to use pip pins on a few of my parts and finding some locally is going to be tough. I have a few but no matching sets.

[manta22]

Thanks, Mike. Actually, it's the side support for a bar that goes across the top of the battery box. If the paint is dry enough today I'll take a picture. That will better explain what my approach is. What size pins are you looking for?

Regards, Neil  Tucson, AZ

[floydjer]

Neil....You`re gas welding the entire chassis??   You are a patient man :cheers:JB

[manta22]

Yes, oxy-acetylene, JB This project was started ages ago; if I were to do it now I'd use MIG. The cost of gas has really gone up the past few years. Oxy- propane would be much cheaper but I've never tried it.

Regards, Neil  Tucson, AZ

[manta22]

The primer & paint was dry this morning so I took a picture of how it goes together; I think the picture pretty well explains what I had a hard time describing.

I'd like some advice about actuating my battery cut-off switch. Unless it was changed in the 2014 rule book (mine isn't here yet), it is legal to mount the switch control on the front or rear of the body. Does anyone have a preference? And is a push to OFF or a pull to OFF the best way to go? I modified my switch so it can be actuated by a push-pull control.

Regards, Neil  Tucson, AZ

[RidgeRunner]

     Neil,

     From the 2014 SCTA rule book.   Page 37, 3.K Batteries: 

     All batteries shall be properly secured with metal framework and faseners.  Plastic tie-downs are not allowed. Both wet cell and dry cell batteries may be mounted in the drivers compartment; however, wet cell batteries must be sealed in a spill-proof box.

     All vehicles shall be equipped with a main battery disconnect switch.  The disconnect switch or a positive mechanical control [cable or rod] for the switch shall be located on the front or rear of the vehicle, operable externally and clearly marked.

                       Ed

     

[manta22]

Thanks, Ed. That looks similar the 2013 rules. I think I'm in compliance-- the hold-down is all metal and the battery box is sealed.

I just mounted my battery cut-off switch this afternoon and I'm hoping to get recommendations regarding a push or pull shut off and whether it is better to mount the shut off at the front or rear of the car.

Regards, Neil  Tucson, AZ

[tauruck]

That looks great Neil.

Very neat solution.

I'm not sure what size pip pins I need yet but they are for holding my rear wheel towing system in place.
I'll email you for advice later. Thanks.