Staging Beam Height
 

What is the height of the staging beams supposed to be?

Re: Staging Beam Height
 

Marty, I think the starting line is 1 1/2 in and the rest are 6 inches. Don't go to vegas with that. Jeff Foster does the elec stuff for NHRA. He should know. I think he looks over here now and then.

Re: Staging Beam Height
 

1-5/8" pre-stage/stage
330' through finish line are 5-5/8
60' is higher, but can't recall the spec off the top of my head. (It's one and a half foam blocks...)

Re: Staging Beam Height
 

Thanks Jeff and Michael

Re: Staging Beam Height
 

1 5/8" is correct for the starting line beam height, (measured at the 1/4" beam emitter hole) but ONLY if that results in the correct rollout using the correct wheel measuring device to ensure that track crown or non-level starting lines don't deviate the specified rollout......the rollout is all that matters. (NHRA spec 11 1/2" to 12" as even lane to lane as physically possible)
2 3/16" to the top of the emitter beam housing, but all that counts is the 1/4" hole in the cap.

Rollout is measured with a 22 inch O.D. wheel with a "trailer" on the track surface to ensure the correct rollout is achieved lane to lane.
We measure ours in both "wheel tracks" in both lanes....we can achieve within 1/4" rollout lane to lane.

Downtrack blocks seem to vary quite a bit.
For NHRA National events:
The 60' beam is spec'd to be 10" to 10 1/2", all other downtrack beams at 5" to 6", but that is measured at the center of the track, not at the beam emitter/receiver location, again, track crown or non-level surfaces affect the true height.

*NOTE*
All interval time beams, speed trap beams, and ET stop beams are measured from the guard beam. (Typical distance between stage beam and guard beam: 12 3/4")
I've never seen a guard beam used at any event other than Nationals or Divisionals.

Source: Section 5: Timing and Recording, of the 2006 NHRA Competition Policies and Procedures Manual.

This manual is specific to the Compulink Startrak Systems.....

This is why some tracks might show slightly quicker intervals on an identical finish ET. (TSI Systems)

The IHRA website used to contain some specifications for their system setups, seems it was the same as NHRA mostly. (Compulink Startrak systems)