Belly Tank Build Diary

[Mike Brown]

Mike,
Congratulations on retirement!!! Now you have full time to work on your car! I retired 10 years ago and can tell you that I was so happy that I am, as most of us are, a "car guy" which means that we can be busy as much as we want working on our love and hobby. So much better than golf.

Enjoy!!!

Rex

Rex,

Thank you for the note of encouragement.  I have been at E.F. Bavis & Associates for 37 years.  The last 30 as VP of manufacturing.  It is just time to leave the decisions to the new guys.  I added a heater to the garage so that I can work on the belly tank this winter getting ready for the mile event in Texas.  The namesake of the car is itisforfreedom.com.  They are a Christian school in the Dominican Republic.  I support infrastructure for the school which includes their solar power system since they are off grid.  So I also have multiple projects in the works.  Neil here on landracing.com has provided electronic design support for a DC power monitoring system that they need.  What a great group of men, surrounding yourself with the brightest group of people that you can find often leads to success. 

[Mike Brown]

I received my Hoosier circuit racing slicks.  They are 27-1/2" tall which is close enough to the 28" tall drag radials that I ran previously.  The Texas event is scheduled for March so the local dragstrip will not be open to scruff in the tires.  I plan to wash them good with Dawn and mechanically scruff them in with sandpaper. 

[WOODY@DDLLC]

Mike, some CW/CCW donuts in your cul-de-sac would be lots more fun than the sandpaper! 

[ronnieroadster]

Mike your not going to a Nascar event. I'm willing to learn so where are you getting the guidance you need to scuff those tires for measured mile runs?

[Mike Brown]

Mike your not going to a Nascar event. I'm willing to learn so where are you getting the guidance you need to scuff those tires for measured mile runs?

Ron,

The tire preparation is my own guidance.  I previously raced 1/8 scale gas (nitro methane) road race cars.  During that period I did a lot of research on tires and coefficient of friction.  In the 60's it was thought that a coefficient of friction greater than 1 between tires and the track could not be achieved.  When dragsters went into sub 6 second runs scientist took another look.  Tires can wear and leave black marks or they can leave rubber through the process of expulsion.  Expulsion simplified is hot rubber adhering to both the tire and the track with subsequent shearing.  You experience this at current top fuel events where there are tiny balls of tire material floating in the air during the entire run.  The goal is to get the tire up to operating temperature quickly without exceeding the maximum operating temperature of the tire.  In racing where sanctioning bodies allow tire preparation, siping is common.  Siping is tiny slits in the surface of the tire made with razor blades.  The sipes allow the tires to achieve racing temperature quicker.  The Texas Mile has a notoriously short track.  It is very important to me to have maximum traction both for acceleration and for stopping at this event.  The hard outer layer on brand new tires form a boundary layer that resists the expulsion process.  My tire preparation plan is to mechanically abrade this outer layer to promote best adhesion, no siping, no grinding away of material to lighten the tire, no grooving or liquids that soften the tires. 

Note that as soon as Hoosier determines that you are racing landspeed they no longer offer any help.  Hoosier has a very specific break-in procedure for these tires.  As far as I can determine this is more about preserving the useful life of the tire than promoting maximum traction. 

I attached a closeup photo of a rear tire that I took off the car.  Note the ridges and "pits" in the surface of the tire.  This is from the expulsion of tire material.  It took a few passes on a prepared dragstrip to achieve this optimal tire surface as well as monitoring the tire wear, temperature and pressure at the mile events.  Unfortunately I will not have the benefit of test & tune sessions to get these new tires up to optimal traction before we go to the Texas event.  The Texas event has historically had a lot of entries which results in 2-3 passes per day.  I would really like to have a few good runs at the event. 

 

[Mike Brown]

I have started on a cockpit fairing.  When I fabricated the fairing behind the roll cage I made two bulkheads.  The second bulkhead had a 1-1/2" wide strip of `/8" thick aluminum welded to it.  I attached 1/16" aluminum sheet for the cockpit fairing to this bulkhead.  By having the fairing split I am able to remove the cockpit body panel and the engine cover independently.  I used the aluminum edging that I bought from Kirkey so the front edge of the fairing is smooth and safe.  It looks like this could be transitioned into an enclosed cockpit in the future. 

[Mike Brown]

I use a tube chute by Shroud.  The chute has worked perfectly without issue however on paved mile courses the deployment bags get worn out very quickly.  I apply gaffers tape to edges but they still get holes and torn apart.  After every event we have to repair or replace the bags.  I was able to source domestically made Aramid fiber cloth in the same thickness/weight as the canvas of the original bag.  A local shoe repair business also does leather and tack.  She was able to sew me up a new deployment bag made from this much higher abrasion resistant material.  We will see how this performs at the next event. 

[Mike Brown]

My fuel tank vent goes to the outside of the car.  I used a small air filter to keep dust, dirt, mud daubers and mice with corn out of the hose.  (I really did have mice fill an AN-10 fuel line with corn while an engine was out)  The air filter stuck out a lot and in the quest for better aero I decided to make it flush.  I contemplated welding up a "cup" to attach it with but everything is so right inside the car.  I looked for commercially produced fuel vents especially those used on boats.  The vent is to the left of the switches. 

[Mike Brown]

I found this fuel tank vent on Amazon for $13.  It is made from stainless steel and has a barb fitting for 1/2" hose.  The threads however are 3/4-16 which is the same as an AN-8 fitting.  The original vent is an AN-8 braided stainless line.  I rarely get this lucky. 

[Mike Brown]

I chucked the vent up in the lathe and machined a 37 degree taper to match the AN-8 fitting on the vent hose.  It fit perfectly. 

[Mike Brown]

The new fuel tank vent installed. 

[Mike Brown]

We haul our car on an open trailer.  I like to use a cockpit cover to protect the belts from UV and rain, etcetera.  The original cover was made by a local guy and secured with snaps.  Since the cover was made the cage has been reduced in both height and width, a rear fairing added and most recently a fairing was added to the cage.  With my wife's assistance we modified that cover to fit.  The front of the cover still fit but had to be modified to attach to the cage fairing.  The cover is secured to the cage fairing with Velcro. 

[Mike Brown]

We made it to the Texas Mile in Beeville.  The course is short, 8,000 feet so shutdown can be challenging.  The tech inspector approved the car for 230+mph however they would only issue me a "C" license good for 160 mph.  I made a licensing pass at 153 mph and talked the race director into a class "A" license.  My next run was 201.1 mph. 
With a 200+ mph time slip and $30 you can purchase a 200 club shirt.  Not to complain but the ECTA and LTA provide hats and shirts just for accomplishing a 200mph record run.  It was a long 1,240 mile drive for us so we took a few days before and after the event.  We stayed a campground in Port Aransas which is on Padre Island.  A wonderful place.  The sand packs really well and they allow vehicles and overnight camping on the beach.  The long flat beach road was tempting but I decided that I preferred the night in the RV verses jail. 

[Mike Brown]

I made a third pass on Saturday at 203.4 mph.  I believe that this was the 14th fastest pass of the day.  There may have been 200 entries.  On that pass I launched the chute early and was hard on the brakes.  The car slowed down for a safe exit off the course but there was little margin for error.  I made the 200 club and will save the car for faster passes with the ECTA (11,000 feet of runway) or LTA (14,400 feet of runway). 

[Stainless1]

Nice passes Mike... Congrats