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Selby Products has a great brochure to help determine screen sizes and the most efficient placement of ramps and cars on the lot. I had originally wanted 80 foot screens on each of our two fields, but upon the advise from Jerry Selby, we have reduced the size of our screens down to 60 feet x 25 feet. Our lots will hold approximately 270 +/- cars, and the 80 foot screens were over-kill. As a slight bonus, the smaller screens should also yeild us a somewhat brighter picture.

Here's what we did:

We took the fixed dimension of the screen, and then set the projection booth the farthest "comfortable" distance away from the screen, using the currently availalbe lenses as our guide to go by.

On the site plan, we drew a line from the center point of the screen perpendicular out to the point of projection. Then we drew lines 40 degrees from perp. at the ends of the screen and extended them out into the field. We then took the 40 degree lines and the center-line of the screen and extended them BACK to the point of convergence behind the screen. This point is referenced on our site plan as the "FIELD CONTROL POINT". Using a "2 1/2 times the height of the screen" rule of thumb, we set the center point of our first ramp
on the center-line of the screen at the calcualted distance. Going back to the control point, we placed an arc with the field control point as it's center, and the center-point of the first ramp as the out edge of it's diameter.

To take the most advantage of the area of the site we have to work with, we "double-ramped" the entire lot on both fields. The field is designed where the distance between the center-line of the windshield of the first car is 27 feet in front of the center-line of the windshield of the car directly behind it. These two cars make up the first series of double-ramped spacing. The distance from the center-point of the windshield of last car in the series to the center-point of the windshield of the first car in the next series of double ramps is 42 feet. This alternates throughout the field all the way back to the rear of the lot.

Hope this helps....

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Barry Floyd
Floyd Entertainment Group
Lebanon, Tennessee

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Barry Floyd
Floyd Entertainment Group
Lebanon, Tennessee

"Ours will be constructed with the center-point of the radius BEHIND the screen. How far back it is placed is directly proportional to the size of the screen."

~I think I follow you here. Are you saying there is some kind of formula that involves the width of the screen? See if my comment below shows that I am understanding what you mean.

"We took the fixed dimension of the screen, and then set the projection booth the farthest "comfortable" distance away from the screen, using the currently availalbe lenses as our guide to go by."

~Would that be less than 320' from lens to screen?

"On the site plan, we drew a line from the center point of the screen perpendicular out to the point of projection. Then we drew lines 40 degrees from perp. at the ends of the screen and extended them out into the field. We then took the 40 degree lines and the center-line of the screen and extended them BACK to the point of convergence behind the screen. This point is referenced on our site plan as the "FIELD CONTROL POINT"."

~OK, here's where I think I follow you: you are drawing edges of the ramps 40 degrees off perpendicular FROM THE ENDS of the screentower, thus the field control point (or apex of the arc) is somewhere behind the screentower and your explanation that this location of the apex was 'proportional' to the width of the screen simply means that the apex/field control point will be farther behind the screen. Another way of looking at it would be to draw up the pie-shaped 80 degree arc on the lot, then fit the screentower within the edges emanating from the apex. Does it sound like I am with it, here, Barry?

"Using a "2 1/2 times the height of the screen" rule of thumb, we set the center point of our first ramp on the center-line of the screen at the calcualted distance."

~Hmmm, is this 2 1/2 times the 25' in your case OR, do you also include the distance between the ground and the bottom edge of the screen? In other words, say you place the screen 15' above the ground, since your screen is 25' in height, would you be multiplying 2 1/2 times 40'?

"Going back to the control point, we placed an arc with the field control point as it's center, and the center-point of the first ramp as the out edge of it's diameter."

~OK, so then if I run single-ramps 40' apart from the ramp in front, I just use the center line, spot where the center would be 40' behind the center spot in my first row, and from the field control point, draw the arc for row 2...etc.?

Thanks for the input, all!