Technical > Jon's Wheel House

Light shields

(1/3) > >>

Guido:
Looking into light shields , are they needed? I see them on some FED's

dreracecar:
Depends,  If your car runs/has overhang in front, then no , because that is what trips the down-track timers. If there is no overhang and the front wheels trip the timers, then a wheel guard is added insurance .  Avoid polishing anything used to stage or trip the timers/beams as the reflection can mess with the signal

JrFuel Hayden:
Most of my light shield customers buy them for the starting line, to prevent red lights , the shield gives you a bit more roll-out, and of course with cars with no nose, the front wheels will click the ET stop.
But keep in mind the start line light beems are on the track [lower] and the finish lights are about 3" above the track.
For years we did not run a light shield on our JF car with 18" wheels with low profile tires , 2.00x18, but the rims had a lip , like Akront or Borrani , and we had no issues of red lighting, UNTIL we raced at a Heritage race in Phoenix, where we had a redlight for the 1'st time . When I checked the other JF teams they also had red lights with the cars that did not have light shields , but no red lights with the cars that had light shields. So yes we have been running a light shield since.
When I get a call for light shields I ask if they are having red lights because the front end is jerking the front end up at the hit, if so just add another 20 lbs on the nose, because a light shield will not help if the wheels are pulling out of the start line lights. 
I hope this helps,
Jon 

dreracecar:
Jon--- stage inferaed beams are on the deck(or close to it)and the old photo-cells were a little higher (but had shields to lower the beams) so the light guard has no influence on roll-out using a standard wheel/tire combo.  Down track timers are 6" up from the track, a 12" square foam block has the reflector in the middle, so covering the spokes of a car without O-H, increases the target area for the beam.  We had an issue at one track where the sun was at the right angle where the refection bounced off the rim and into the beam causing it not to register. The other guy was pissed at us for trying to burn him down, but it was just one of those things, we were well past the line and the stage lights never came on

JrFuel Hayden:
Bruce, then nobody needs light shields ? Then why when we raced Phoenix did ALL of the cars without shields red light and all that had light shields not red light ?
I witnessed a red light problem at a national event at Vegas with a Comp Elim A/AP when it red lighted without moving [ video] , not even tire wringle, NHRA tested and tried to doublecate, and NHRA decided that a photographer standin shooting at the startline, outside the K rail , was the cause of the flash camera reflecting off his front wheel because the photgrapher was actually shootting his competitor because they left 1'st. That's why NHRA does not allow photos at the start line now. Allan Ellis has since blacked out his wheels. 
How's Dennis Murphy car coming along ?
Jon

Navigation

[0] Message Index

[#] Next page