What do you get when you take any airplane and more than double its horsepower? For one thing you get much bigger grins every time you move the throttle forward for takeoff. The 450 Stearman, the so-called “Super Stearman,” is a classic case in point. Originally born with a puny 220 hp, W-670 Continental radial in the nose, when the airplane is given a noseectomy and an R-985 Pratt and Whitney with 450 fire-breathing horses is grafted on, the airplane develops an entirely different personality. What had been a leisurely school marm intent on teaching a military cadet the very basics of aviating, becomes a belligerent show-off eager to demonstrate what it can do.
The 450 Stearman HAD to happen. Right after World War Two, there were literally thousands of both Stearmans and BT-13 Vultee trainers sitting around for bargain basement prices. The Stearmans were ideal for crop dusting, although underpowered, but the Vultees were not good for much of anything. The BT-13s did, however, have a 450hp P & W and prop up front that were worth the entire price of the airplane (generally about $400). The conclusion was obvious, so ag-operators snatched many of the old BTs up, the engines were yanked off and the carcasses pushed off to the side and ignored. For years, cannibalized BT-13s littered grassroots airports nationwide.
The airshow guys were right on the heels of the dusters but they went the ag-operators one better: they wanted to improve the airplaneís roll performance as well as its ability to climb, so an extra set of ailerons were installed on the top wings and slaved to the bottom ones. Now, the old airplane could not only leap off the ground and had a modicum of vertical performance, but it could actually roll with the best of them. Sort of, anyway.
The stodgy old school teacher had been turned into a rock ‘n rollin’ circus performer.
From a pilot’s point of view, you have to have flown a stock Stearman to appreciate the dramatic improvements airshow types have made to the airplane. Flying aerobatics in a stock Stearman is a continuous, irritating cycle: nose down, down, down, wait, wait, now pull. Do one maneuver, then climb, climb climb to replace the altitude lost.
Where an original 220hp Stearman spends a lot more time diving to gain energy and then climbing for altitude than it does doing aerobatics, the 450hp bird has almost all the energy it needs bolted to its nose. It needs only a gentle nod down before it’s ready to be pulled up into whatever maneuver the pilot desires. So, when you see John Mohr doing his airshow routine in a 220hp Stearman, you are seeing one of the very best aerobatic pilots in the world, because his airplane isn’t doing a single thing to help him.
The extra ailerons do wonders for the airplane in rolls. Not only are the forces lighter (a stock Stearman is a “manly” airplane), but the roll rate is such that, although it’s not a Pitts or Extra, it lets the acrobat do point rolls or anything else around the longitudinal axis with no danger of separating a rotator cup.
The Super Stearman is known as “super” for a reason. Otherwise, it’s just another Stearman and the grin factor isn’t nearly as high. –By Budd Davisson