Asymmetric Power v George Stewart's Zero Boost method

Our newest Affiliate and old friend, George E. Stewart DFC, former wartime Mosquito pilot and trainer, has generously shared with us these photographs illustrating the original asymmetric power technique that resulted in so many ground-loops and crashes on take-off, and describes the Zero Boost method he developed for making Mosquito launches safer.

George writes:

“These three photographs show the original technique (asymmetric power) taught at High Ercall, #60 O.T.U., when we first checked out on the Mosquito, September 1943, as we gingerly countered torque and crosswind, easing the port throttle ahead of the starboard (used a lot of runway)!!

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Asymmetric power made clearly visible by the single prop vortex

The second was the too often resulting ground-loop, which followed when things didn’t work out too well. These examples happened in China, when we instructed there in 1948 and we had dozens of these during our 9 months there, before the cure.

Wrecked Mossies China

Results of the all too regular ground-loop – China 1948


The third was taken by me at that time, in Shanghai, and inspired my Zero Boost method used in flying KA114.

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The Missing Link between discovery and use of the Zero Boost method – note asymmetric power

I assumed that since this was prop wash, with NO slipstream, that there would be rudder control from the moment you released your brakes, instead of at 70 MPH, when the tail would have come up, putting the rudder into the slipstream, well down the runway.

Asymmetric Power became redundant!  Balanced Power at Zero Boost on the brakes before rolling ahead, was born!

Simultaneously as you release the brakes, Power quickly to the gate; Stick full forward (we’ll get there eventually), and full right rudder to counter the resulting left turn from torque and steer straight down the runway. Takeoff power is usually achieved by the time you’d run the length of the aircraft!!

The huge bonus was that the critical Single Engine Safety Speed would easily be reached by the end of the runway!!!! (not so, the old way). In hopes to establish this as a standard, it is my recommendation that the Gate be set at 14 lbs Boost, to continue that capability.”

KA114 takeoff Hamilton

The Zero Boost method in practice as Mike Spalding launches Mosquito FB.26 KA114, June 2013

Our sincere gratitude to George for sharing these pictures with us, along with his invaluable advice which will help ensure that when we eventually get The People’s Mosquito ready to roll, she will take off safely, as has been the case with KA114.

Credits: B&W photographs © George E. Stewart, Colour photograph of KA114 © Neil Hutchinson

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