N941WR
Legacy Member
The other day I ran across this post here on the VAF forum:
Cruising along at 8,500 MSL above the 1,000 MSL dirt and you have an engine failure. Assuming the prop stops, providing the lowest drag configuration, you should have 912 square miles in which to set the plane down in.
Here's how my math breaks down:
8500 - 1000 = 7500 feet AGL
7500 * 12 = 90,000 foot radius
90,000 / 5280 (feet in a mile) = 17 miles
3.14 * 17 ^ 2 = 912 Square miles (Pi R Sq - You do remember that formula?)
Using the same math, if you have the same engine failure at 1000 AGL, you still have a 16 theoretical sq mi circle in which to land.
Now, using that 95 MPH Best Glide speed and figuring your decent rate goes up to 700 FPM, from 7500 AGL you will be on the ground in 10.7 minutes. From 1000 AGL it will only take you 1.4 minutes.
Just some more food for thought on this Thanksgiving day.
Using the 12 to 1 Best Glide Ratio I came up with the following:JimLogajan said:The CAFE Foundation measured the following glide ratio for the RV-9A [1]:
* Best glide ratio, idle power, coarse pitch, 1738 lb, 95 mph CAS: 12 to 1
* Min. sink rate, idle power, coarse pitch, 1725 lb, 81.7 mph TAS: 664.2 fpm
Cruising along at 8,500 MSL above the 1,000 MSL dirt and you have an engine failure. Assuming the prop stops, providing the lowest drag configuration, you should have 912 square miles in which to set the plane down in.
Here's how my math breaks down:
8500 - 1000 = 7500 feet AGL
7500 * 12 = 90,000 foot radius
90,000 / 5280 (feet in a mile) = 17 miles
3.14 * 17 ^ 2 = 912 Square miles (Pi R Sq - You do remember that formula?)
Using the same math, if you have the same engine failure at 1000 AGL, you still have a 16 theoretical sq mi circle in which to land.
Now, using that 95 MPH Best Glide speed and figuring your decent rate goes up to 700 FPM, from 7500 AGL you will be on the ground in 10.7 minutes. From 1000 AGL it will only take you 1.4 minutes.
Just some more food for thought on this Thanksgiving day.
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