The standard model 75 Stearman has a very good control lock system which locks the forward and rear cockpit controls in a neutral position so that the flying surfaces don't bang around in the wind.

The original mechanism consists of a lever and various other bits that attach along the lower left side of the cockpit area. In the photo below, you can see part of the mechanism in the big red handle protruding just forward of the throttle quadrant.

In substituion for the control lock mechanism, many Stearman owners use the time-tested seat belt around-the-stick arrangement to hold the controls from flapping in the breeze. However, this does nothing to hold the rudder in place. As a matter of fact, when left in this condition, a strong wind can slam the rudder so hard against the stops that an upraised elevator will then puncture the fabric on the rudder! This is a bad thing.

For a variety of reasons, many 450 Stearmans cannot use the original control lock system, even when the spray equipment is removed. The number of control rods required for the constant speed propeller, as well as any extra oil lines running back to a rear-mounted oil tank or cooler, and other custom modifications, can make re-fitment of the original system impractical or impossible.

Confronted with this situation, I searched and found a solution in the York Gust Lok made especially for the Stearman. At a price of around $200, I could not design and fabricate a system on my own to compete with the York unit. You can contact York at www.gustlock.com as I did.

On initial inquiry, they sent me the drawing below.

Drawing of the Gust Lok for the Stearman model 75.

Suitably convinced that this might do the trick, I sent off for the unit. The Gust Lok was delivered quickly, and contained all the items you see below, as well as detailed instructions on fitting the unit to the airplane, and even an allen wrench with which to accomplish the fitment.
Although specifically designed for the Stearman, it must be custom fitted with a few set screws to position the stick where you want it, and provide correct tension with regard to the rudder pedals. This adjustment is necessary due to the fact that the Stearman rudder pedals are adjustable fore and aft.

Due to the way the front seat is installed in relation to the rudder pedals, the Gust Lok must be used only in the front cockpit. Duster airplanes with no front furnishings cannot use this.
After giving the instructions a brief read, and inspecting the Gust Lok, it took about 5 minutes with the allen wrench, and 2 or 3 fitments to get a good, solid fitting of the Gust Lok.
The quality of the workmanship on the Gust Lok, and the materials used are entirely acceptable and very professional. Everything fitted and worked as it should, and the paint is good, and appropriate in bright red so one cannot lose it in a dark cockpit.

The Gust Lok uses a knee joint to apply pressure between the base of the stick and the bar which stretches from the upper stick to the rudder bar. Once adjusted, the lock is installed in just a few seconds, and is easily done from outside the cockpit. A padded clamp fits around the middle portion of the stick, while forks fit to each rudder pedal, as you can see in the cockpit photo below.

The unit weighs about 3 pounds, and disassembles down using the knee joint, and a lynch pin at the rudder bar. I keep it in its plastic shipping bag, and it fits well in the baggage compartment.
It holds the controls in a neutral position, and does its job well. A lock could be incorporated to prevent theft, but would be adding needless complexity in my mind.

If I were to change anything, I'd add a nice bag for stowing, and make the forks that fit around the front pedals a bit longer to fit more closely. Otherwise, the unit it very satisfactory, and as I mentioned, I could not make one for the purchase price.
Closeup of the padded clamp which fits around the middle of the stick.

I have no problem recommending the York Gust Lok for your Stearman.

Contact me if you have any questions or comments via Stearman Email