Does frost alter the shape of airfoil?
- Thread starter ZUKO
- Start date
Which question are you asking:
"Does frost alter the shape of the airfoil?"
or
"Does frost alter the flow of air across the airfoil?"
NASA Aircraft Icing Programs.
"A Pilot's Guide to Ground Icing" has some pretty good information on frost and its affects.
"Does frost alter the shape of the airfoil?"
or
"Does frost alter the flow of air across the airfoil?"
NASA Aircraft Icing Programs.
"A Pilot's Guide to Ground Icing" has some pretty good information on frost and its affects.
the_dmn8tr
New Member
The frost disrupts the smooth flow of air across the airfoil. In the Gleim Private Pilot, Page 26, section 1.5.
casey
Well-Known Member
frost does disrupt an airfoil, esp in laminar flow.
leardriver
New Member
Yes, even small amounts of frost can change the shape and airflow over an aircraft's surfaces. Frost reduces performance and changes flight characteristics by increasing drag and reducing max lift.
ZUKO
Well-Known Member
Yes, even small amounts of frost can change the shape and airflow over an aircraft's surfaces. Frost reduces performance and changes flight characteristics by increasing drag and reducing max lift.
How ever, the airfoil shape stays the same? I think I got my words mixed up on the test. :argue:
tgrayson
New Member
From AC 00-06A Aviation Weather
Frost does not change the basic aerodynamic shape of the wing, but the roughness of its surface spoils the smooth flow of air thus causing a slowing of the airflow. This slowing of the air causes early air flow separation over the affected airfoil resulting in a loss of lift. A heavy coat of hard frost will cause a 5 to 10 percent increase in stall speed. Even a small amount of frost on airfoils may prevent an aircraft from becoming airborne at normal takeoff speed. Also possible is that, once airborne, an aircraft could have insufficient margin of airspeed above stall so that moderate gusts or turning flight could produce incipient or complete stalling.
B767Driver
New Member
An interesting sidebar to this conversation is FAA SAFO 06014 (Safety Alert for Operators) and how it expands upon FAR 91.527.
The FAR states that you can takeoff with frost on your wings if it has been polished smooth. However the SAFO states that you should only peform this procedure in accordance with an aircraft manufacturer's recommended procedure. A review of various manufacturers shows that none have an approved procedure for frost polishing.
A SAFO is a safety recommendation and is not regulatory...but verbage in the SAFO hints that regulatory changes may be in the works.
You can view these at www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/safo.
The FAR states that you can takeoff with frost on your wings if it has been polished smooth. However the SAFO states that you should only peform this procedure in accordance with an aircraft manufacturer's recommended procedure. A review of various manufacturers shows that none have an approved procedure for frost polishing.
A SAFO is a safety recommendation and is not regulatory...but verbage in the SAFO hints that regulatory changes may be in the works.
You can view these at www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/safo.