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**hangarb7** · 01-04-2006, 11:24

Re: VASI - Anyone?

There was an airstrip here in south western Pennsylvania (West Penn Airport...gone but it's rumored that it may open some day again, improved and lengthened with an industrial park next door...Rock Airport or something) that had a mechanical, poorman's vasi. It originally probably took a little effort to set up but it worked very well on a narrow, short strip.

It was essentially two plywood boards, each about 4' X 4', painted yellow and supported by steel angle irons set in concrete. They were perpendicular with the runway, on-edge, with the closest to the approach end set to be taller than the one that was set a little farther down the runway (I'm guessing about twenty feet but that's where the experimenting comes in... memories can be dim).

The top edge of the plywood was painted black. The idea was that, on the proper glide path, the site line was across the top of the boards, with the black lines close together. When you were high, you could see too much of the second board and when low, you couldn't see the second board at all.

It worked really well. I would think a lighted vasi could be designed using the same method and the angle could be figured mathematically for placement of the four rows of lights. The only problem is that the lights would need a narrow plan of view. Maybe a shadow tube assembled over the light bulb to give a narrow exposure.

Or buy some exterior plywood ;-)

Jack Dernorsek
N44057
'46 BC12D