Canopy causes cockpit fire

BllFs6 wrote:

5% of the sun's energy is a big problem



Do the cals and get back to me....

And dont say the but the canopy is HUGE....because size in this case doesnt
matter

Within reason, the ONLY parameter that makes a difference in melting/burning
something using the sun and a lens or a mirror is the F ratio.....ie the focal
length of the lens/mirror divided by effective diameter....

The focal ratio of my canopy is about 1 when it is reflecting light onto
my glare shield



And to get stuff hot enough that number needs to be around 2...give or take
...and that assumes a very high transmission/reflection number....drop that
number to 5 percent and no real problem...unless your target is a dark
chocolate bar....

Now bring that number back up to MOSTLY transmitting or reflecting and
poof.....hence worrying about grazing reflections....

Now, you may not believe me....but the "hotness" of the "burn spot" doesnt
really matter (to first order) whether I have a lens/mirror 2 inches across or
60 inches across....only the f ratio matters...

take care

Blll

The focal ratio of my canopy is about 1 when it is reflecting light onto
my glare shield

okay,

thats a number I can play with...

whats the focal length or effective diameter?

take care

Blll

Well,
Friday, at the end of the flight around % 0'clock on a sunny Central Texas
day I put my canopy on the ground and my Garmin GPS down beside it for not
more tha 15 minutes.
Now I've got black spot the size of a dime ont he screen.
Don't know what it's gonna cot to get fixed.
Be careful out there!
Cheers!, Pete (sun power believer now!)

"BllFs6" wrote in message
...
The focal ratio of my canopy is about 1 when it is reflecting light onto
my glare shield

okay,

thats a number I can play with...

whats the focal length or effective diameter?

take care

Blll