On Some AT-802F specifications

Referring to these AT-802F specifications from the Queen Bee webpage, I want to spend a few moments describing some of the specifications in a little more detail. Queen Bee is an authorized Air Tractor dealer and has a SEAT contract with the Bureau of Land Management (BLM). A complete listing of BLM SEAT contracts as of July 1, 2008 may is listed in this pdf document.

A word on the weight and useful load specifications. The aircraft has a maximum rated weight for take-off and landing. This would be a fully loaded aircraft including pilot, fuel, and payload (water/retardant, additional cargo and equipment, etc.). Useful load is difference between the maximum weight of the aircraft and the empty weight. So, the useful load includes pilot and crew (if any), cargo, water/retardant, and fuel. It also includes anything attached to an airframe that was not installed at the factory as factory installed equipment.

Water or retardant is carried in the 820 gallon hopper.

The AT-802F has an 18 gallon foam tank. This is for the foam agent that can be mixed with water. When water is loaded into the hopper on the aircraft, the foam agent is mixed in at the specified ration.

The final specification that I want to write about is something called stall speed. I ran across this spec on the Air Tractor Company’s page for the AT-802F. Click on performance, note the three stall speeds. As I understand it from my correspondence with TL Stein, stall speed for an aircraft is the speed where the forward speed of the aircraft is not producing enough air flow over the wings to produce lift or support the airplane at its altitude.

When a pilot is landing an aircraft, the plane is just over stall speed.

If you have used the link above to look at Airtractor’s performance numbers for the AT-802F, you will note the following numbers:

Stall Speed, Flaps up: 105 mph (169 kph) at 16,000 lbs (7 257 kg)

Stall Speed, Flaps Down: 91 mph (146 kph) at 16,000 lbs (7 257 kg)

Flaps are usually on the trailing edge of the wings. If you fly on a commercial airliner and are seated at a window seat near the wings, you may have noticed that the flaps are in the down or extended position when the pilot is landing the plane. This reduces the stall speed allowing the aircraft to approach landing more slowly. In some aircraft, flaps may be partially extended for take-off. Conversely, if flaps are in the up or retracted position, stall speed is higher. For a discussion on flaps with pictures, see this wikipedia article .

I will be writing more about stall speed in my next post.