BT-13 Opener

Vultee's BT-13 Pilot Maker
Good vibrations from the Vultee Vibrator

Text and photos by Budd Davisson, Air Progress, August, 1972,


M043 is really pretty, inside and out. The outside is smooth and shiny, and the inside is covered with a completely intact coat of zinc chromate. Not even the rudder pedals look worn. We had occasion to open the baggage compartment, and I saw that the zippered canvas lining looked clean and fresh. It this is an unrestored airplane, I'd like to see what Riddle would do if he restored one.
He always parks with the flaps down to keep people from stepping on their fabric covering when hopping aboard. It's a sizeable step from the ground to the wing walk, and the flaps are tempting.
Once up on the wing, there is no way to step over the fuselage side and into the cockpit without planting a foot squarely in the middle of the parachute. You then let yourself down while hanging on to the windshield frame. Once inside, I was surprised first by the excellent visibility, and second by the sophistication of the panel. I don't know if all BT-13s are laid out this way, but M043's front room somehow seemed to be much more complete and well thought out than its contemporary, the AT-6. T-6 panels, especially early ones, look crude in comparison.

BT-13 Cockpit
The Vultee cockpit feels somehow better laid out than a Texan's, although I can't say exactly why. It just feels that way.

Even though it looks impressive, there really isn't very much complicated about the BT. It has the same knobs and instruments any other fixed-gear airplane with a constant-speed prop would have, only in different places. The rudder and elevator trim are both by wheels rotating fore and aft under your left arm with a long wobble pump sticking up between them. The flaps are also under your left hand and are operated by a big crank that gives two degrees of flap for every rotation. Aside from these controls and the prop pitch mounted on the quadrant, everything else is where it would be in any puddle jumper.
Bill told me to go check myself out, but vetoed that action right away. I could just see myself hanging from a tree after I'd bent his shiny toy. I don't think it's terribly smart to go charging off in air machines I know nothing about, so I tossed a friend who had lots of BT time in the hack seat, just for insurance.
Since there is no electrical boost pump, fuel pressure has to be built up with the wobble pump before you can fire it up. I pumped until the pressure was in the green and gave it a couple shots of prime. Craning my neck around both sides of the open canopy, looking to see if anybody was in position to get smacked, I yelled, "Clear." With one hand on the mag switch, I pulled the starter switch up with the other and waited until the third blade came by before I switched the mags on. Almost immediately, a dull series of explosions told is we'd been successful in lighting the fire.
There is nothing in the world like the feeling you get when taxiing a military airplane. With the canopy open, the initial burst of power it takes to get moving whips around in the cockpit, getting you mentally prepared to do some military-style aviating. Your feet are wide apart and nestled in aluminum cradles, and the throttle and stick in your hands are both man-size, like everything else around you. It’s a great feeling, even if this is only a trainer.
Even though the tailwheel is steerable, I found myself using occasional stabs of brake to keep from munching on a Cessna or something. Once rolling, especially on concrete, practically no power was needed to keep it in motion. At the end of the runway, I had to remind myself to put the prop up to full rpm before doing the mag check, because the BT Is started with the prop control all the way back to keep the prop from robbing oil from the engine during warm-up.
Traffic cleared, lined up on the runway and prepared for my usual Davisson-versus-the-airplane battle. I remembered all too clearly some of my careening takeoffs in SNJs and other similar "trainers." Bill had told me to use only 30 inches of manifold pressure to get off the ground, but I decided I'd worry first about staying on the runway, then I'd worry about power settings.
I eased the throttle forward, and as expected, the P&W started pulling us forward at a pretty good clip. I eased the stick forward to get the tail up and suddenly found I had better visibility than in anything Wichita produces. Then, long before I was ready for it, this big, hulking piece or iron wafted itself up off the runway as if it were imitating a Taylorcraft There was absolutely no effort involved! All I did was add power and raise the tail; the airplane took care of the rest. It was a totally unmilitarylike departure, to say the least
Once safely off the concrete, I checked the power and found I had used 36 inches, so I immediately brought it back to a climb setting of 28 inches. Climbing out at various airspeeds from 90 to 110 mph convinced me this thing was neither a Bearcat nor a Pitts. About the best we could get was 600 fpm. A Cherokee 180 would outclimb us.
I never know how to describe military controls: I don't know if they are light, or if the stick is so long that it is overcoming resistance through pure leverage and brute force. It doesn't take much effort, but it does take some movement.
Grumbling along in cruise at 1850 rpm (I could almost count the blades) and 23 inches, I searched for some of the famous vibration that had given the Vultee its nick-name, but I found none.