How many of you remember the ROT for DA. I didn't so I looked it up.

Standard temp sea level 15C 59F

Standard temp drop per 1000' -2 C -3.5 F

Every degree Centigrade above standard add 100'

Every degree Fahrenheit above standard add 60'

Example: Smiley Creek 7100' Standard temp 34F

Say it is 80 F that is 46 F above standard or 2760'

2760+7100= 9860

Landing at Big Creek good, Landing on a PU truck at Big Creek bad.

Rob,

Now I guess I am going to have to forget (hold my beer and watch this)

I figure if I am not off on the first 1/4 of the runway Its hot out

I am glad you looked that up though cuz I have to change jets on the Banshee now that its hot out again.

Another "ROT" that I have aways liked is, (ref.Sparky/Mountain Flying Bible).

You need to have 3/4 of your rotational speed by the time you meet the 1/2 point of the runway you are on. If you can't do that, abort and wait for, or create better conditions.

Gary

Bingo. That is the one I use.

After a recent trip to Smiley Creek, and feeling the vast difference from DA, I made an Excel spreadsheet that not only does my weight and balance, but figures my take off roll and climb using altitude and temp. I even added a spot for the added roll for grass. Seems to be pretty accurate, within a few hundred feet anyway. Nothing fancy but I will send to whoever wants it.
Erick

Erick, hi. I want to try yout Excel spread sheet.

I'm in Coeur d'Alene.,Id now. Glacier NP tomorrow.

Rob

Actually Sparky's rule is

71% of rotation speed by 50% of the runway.


I use this one often always worked for me. I very much like sparky's rules

Spreadsheet sent to all who asked. Let me know if I missed someone.
Tail winds
Erick

Offered for what it might be worth ~ DA calculator:

http://thenativepress.com/aviation/takeoff.html

If, ya have a tranponder with encoder,
Then, simply install a neat little DAVTRON instrument.

Gives ya: Battery voltage, Temp F, Temp C. Pressure Alt. AND DENSITY Alt.

NO math, just read the result.
TOOO simple
Extremely quick
Just takes a glance.

Chris C.