Dehavilland beaver performance

[MTpilot]

A friend of mine is a geologist and will be going to a lot of backcountry lakes in Alaska. He needs to figure out which ones will require a helicopter and which ones can be gotten into with a beaver. Anyone have a good idea of the criteria a beaver pilot would use to determine what is acceptable? Thanks in advance, Bill

P.S. He is doing cost analysis.

 

[imacdog]

The Beaver's performance varies widely based on its load. A lightly loaded Beaver departing with a few people on board and a couple hours of gas can take off in 500-600 feet at sea level during light winds and standard temperatures. A fully loaded Beaver can easily top 3000 feet just to get off the water. I have had a few takeoffs during a warm, calm day with a full load that were around 5000 water run. Once off the water, angle of climb is poor so consideration must be taken for obstacles. It can take an extra 1000 feet just to get above tree height. Wind, temperature, engine and float condition, load, and pilot technique will make a big difference in performance. Fortunately the Beaver's engine is supercharged so takeoff power is not reduced up to about 3000 feet. The Beaver will land in a much shorter distance than it can take off so landing is usually not a consideration.

 

[MTpilot]

Imacdog, Thanks for the quick response. Should I tell my friend the lakes need to be at least a half mile long or is it something the pilot would just have to see, I'm just looking for a general rule of thumb, Thanks again, Bill

 

[imacdog]

Chances are the pilot will have experience flying into or around the lakes that your friend will be going to. If your friend can show the pilot a map of intended lakes the pilot would probably be able to offer which lakes he can go into. A half mile lake should be doable in a Beaver with a light load as long as there isn't a considerable climb requirement after takeoff. Even with a lightly loaded Beaver I have rarely seen north of a 500fpm climb.