Belly Tank Build Diary

[Mike Brown]

Wow, the new look of the site is fantastic. 

We raced at the Spring ECTA event in Arkansas.  It was a great time.  I prefer to evaluate one change at a time, so no wing on this run.  The last race the car was handling very poorly.  I replaced the Mickey Thompson drag radials with new Mickey Thompson tires that did not have the funky patch.  This change alone and the handling was back to very good.  I bumped my record up just a bit to 210.773 mph in the standing mile.  A new track record was set by a 2009 Corvette driven by Kelly Bise at a blistering 280.025 mph. 

[Mike Brown]

After the second 210+ mph pass the windshield broke on the turn off just before the return road.  Probably 50 mph or less.  No other damage as the broken piece was still held to the car with a fastener.  The windshield was fabricated from 1/8 polycarbonate after failures from thicker acrylic.  Polycarbonate is notch sensitive so all the edges were polished to reduce the chance of cracking.  Inspection revealed that where the windshield rubbed on the body there were deep scratches.  I believe this is where the crack started.  We did not have a spare and stopped racing at this point.  I am fabricating a new windshield from polycarbonate and will use some sort of material on the edges to prevent wear/scratching.  Possibly adding some bracing to reduce deflection at high speed. 

[Stainless1]

Nice Pass Mike... just wondering why you didn't stay in if for the 2K... brakes?  running out of room after the mile to get stopped?

[Mike Brown]

Nice Pass Mike... just wondering why you didn't stay in if for the 2K... brakes?  running out of room after the mile to get stopped?

I don't have any valid reason for not running the 2K.  I have a chute and good brakes, the ECTA course in Blytheville Arkansas is 11,400 feet long.  The car was designed specifically for mile racing.  I ruined all four tires on a 1-1/2 mile 221+mph pass in Loring so there is that.  All of my other passes other than Loring have been at the mile so it makes sense from a comparison point of view.  I have not ruled it out, maybe in the future.   

[Mike Brown]

The data from the 210mph pass.  If you look at the yellow trace in the middle graph you can see that the supercharger boost remained constant in high gear.  It had been dropping off due to the blower belt slipping.  A new belt properly tensioned resolved that issue.  If you look at the white trace on the bottom graph you can see that I am still pedaling the throttle in first and second (looking for traction) but there was also a few points less than 100% in high gear.  I think that may be from bouncing around in the cockpit, the track is not very smooth at that point, something to think about and work on next time. 

[ronnieroadster]

Mike the windshield we run on our Rear Engine Roadster is similar to what yours looks like. Except around the outer edge we have an aluminum strip that supports the plastic. Overall its simply a frame similar to what one would use for a convertible windshield. Having this stable structure support around the plastic has eliminated any type of deflection.
 Ron

[Mike Brown]

Mike the windshield we run on our Rear Engine Roadster is similar to what yours looks like. Except around the outer edge we have an aluminum strip that supports the plastic. Overall its simply a frame similar to what one would use for a convertible windshield. Having this stable structure support around the plastic has eliminated any type of deflection.
 Ron

As Always thank you Ron for advice from someone that has been there done that. 

[Mike Brown]

I started fabricating a new windshield.  I purchased polycarbonate material from Amazon.  They shipped me 1/4" versus the 1/8" that I ordered.  It appeared that the 1/4" material could be satisfactorily formed so I used it. I used an old acrylic windshield that had cracks appearing for a form.  Heat from a Calrod heater was used to reduce stress as it was clamped to the form.  All the edges were polished after cutting.  I tried to post a picture but kept getting an error that the attachments directory could be located.  I will add the photo later. 

[Mike Brown]

A photo of my windshield fabrication fixture. 

[Mike Brown]

The lakester will be at the Keeneland Councours in July.  They called and asked for higher resolution photos of the car.  I asked Nancy Riley, a friend, if she could help out.  As always Nancy exceeded all my expectations.  A few photos from that session. 

[Mike Brown]

I added aluminum edging to the new 1/4" polycarbonate windshield.  The edging was some thin wall 1/2" aluminum tubing that I had in the shop.  I fixtured the tubing up on the mill so that I could reposition the tubing and mill a 1/4" slot in it the entire length. 

[Mike Brown]

The tubing was then hand formed (no annealing) around a 1/4" mandrel in my vice.  It turned out good.  I will secure it in place with a low modulas urethane adhesive.