Steen Skybolt:
The Man-Sized Biplane

Text and Photos by Budd Davisson, Sport Flying, 1971

What follows is a pilot report on the first Skybolt the late Hale Wallace ever built. The year was 1971. Years later Hale was to purchase the design rights and set up his own Steen Aerolab supplying kits and components. Hale was one of the most fantastic craftsmen I have ever known. He made “perfection” look sloppy. He was also one of my good friends and I hated it when cancer took him. However, even in dying, he set an example for everyone to follow. He faced his own death with a humor and dignity I can’t expect to duplicate. He had a little of the junkyard dog in him, a little bulldog and a whole lot of toy terrier, as he just loved having fun with airplanes. He was one of a kind.

My mind was yelling at me, "Aaahy, Dummy! That was the horizon that just went by, Do something!" So, I hammered the stick forward and punched opposite rudder, bringing the snap roll to an unbelievably sloppy halt.
"Tilt!" my brain chided again and I obediently brought the wings back to a semblance of level flight. I had been suckered! The Skybolt had played around on the corners of my consciousness at the airshows for years and I had always ignored it, passing it off as a chubby, backyard knock-off on an S-2 Pitts. But, as I yanked and pushed my way around the sky in Hale Wallace's Skybolt, I had the subliminal feeling that the airplane was getting back at me and ultimately would have the last laugh.

The lines of the Skybolt are vaguely Pitts-like in that the top wing is a swept one-piece unit, while the bottom wings are straight. It should be noted that Curtis Pitts designed a three-piece top wing for the current Steen Aerolab who offers it in their on-line catalog ( It is a much easier to build wing than the original.

I had stuffed Wallace in the front pit of his airplane so I had a two place machine that was doing what it was supposed to be doing—carrying two people, some fuel and flip-flopping around the sky. Wallace, of Binghamton, New York, had not only loaned me his Skybolt, but also volunteered to play ballast bag while I poked into the various corners of the Skybolt's soul. It was, I surmised, the worse possible situation to place the airplane in for an aerobatic evaluation. With the extra weight it wouldn't be performing at its best, so I could assume that whatever I found out about it would only be improved when flying solo. If that's the case, then as a single-place airplane the Skybolt must be a real brain breaker because even with two of us aboard it was no slouch.

The Skybolt bears more than a casual resemblance to a two-hole Pitts. It's a bunch bigger, 24 versus 20-foot span, but weighs about the same, 1100 pounds empty. Wallace uses a IO-360 solid shaft 180 Lycoming and a fixed pitched prop and weighs in at 1150 pounds, exactly what my 200 hp S-2 Pitts does with a constant speed. But, remember, the Skybolt is a sizable amount bigger. The airplane has a "feeling" of being bigger when you're walking around it, but its flat ground attitude tends to hide some of its size. I think I was most impressed by its size when I tossed my butt up over the gunwhales and settled into the seat. The flight deck is so large that it makes my Pitts seem like a chrome-moly straightjacket (which it is) by comparison. No problem getting my pointy-toed Texas wedgies past the seat to -the rudder pedals in a Skybolt.

The gestation of the Skybolt is a well known and, at this point, often told story. LaMar Steen, school teacher, wanted an aerobatic airplane. So he designed one. Students at Manual High in Denver built it. He flew it, liked it. Had the structure analyzed by engineers. Others liked it. More built.

That's where it came from, but, as I flipped the master on and wobbled up some fuel pressure, I wanted to find out where it is right now. I wanted to know what kind of bird it is in the air, not on the drawing board. So, keeping the mixture lean, I pushed the starter switch, and, as it began to light off the residual fuel in its intakes, I pushed the mixture forward and settled back to follow the Lycoming wherever it wanted to take me.

As I taxied out, making gentle "S" turns to see around the ridiculous snout all biplanes seem born with, I worked the controls, trying to get a feel of what moved what. I wished that I could have done the same thing on a number of other Skybolts because I can't believe they all feel as good as Wallace's. Slick is the only word to describe it. The only friction in the entire airplane was between my tusche and the seat because the throttle, stick, rudders, everything, felt like they were stuck in butter, with virtually nothing touching them. That's probably a credit to Hale Wallace's meticulous building techniques rather than the basic design, but it's hard to tell without checking several other airplanes. (Ed note: In later years I found that to be the case because the ailerons on Skybolts vary considerably according to the builder.)

There is also a different landing gear for the Skybolt now available that is a single leg per side, ala Marquart Charger, with internal shock system.

You sit low in a Skybolt. Or at least I do. It's traditional biplane all the way, making the pilot look like a midget in a manhole. I've always felt I looked like the caricature "Kilroy's Been Here," with my eyes and nose the only thing higher than the cockpit combing. We were working off Sussex International's runways in New Jersey and even with their adequate width, you don't see much pavement from the back of a Skybolt. So, as I picked my way through the puddles of a traditional messy East Coast spring, I carefully sized up the runway that was visible and decided to keep the sides right where they were during the takeoff and landing rolls.

We had a fairly healthy crosswind so I was cautious with everything on that first takeoff. I fed the coal to the Lycoming slowly at first, letting us pick up speed at about the same rate my brain was functioning. No reason to scare the hell out of myself by dropping the hammer too hard. The Skybolt, even with only 180 hp did its best to play fighter, and tore down the painted stripe as if it had someplace to go in a hurry. I hoisted the tail just a little and sat there, tail low and peeking at both sides of the runway at once, while we raced up to a speed where airplane thought it'd like to go flying.

At no time, not even in the crosswind, did I have to do a tap dance on the rudders. It took a little pressure one way or the other, but for the most part the airplane shot straight ahead with no tendency to ricochet off runway lights on either side. It seemed to have a surprising amount of directional stability.

For some reason or other I wasn't really aware of rocketing down the runway with the noise and wind threatening to yank my head off, my eyes clicking back and forth from side to side and all the other excitement that usually comes with taking off in a Pitts or something similar. The headsets kept out most of the racket, but otherwise, everything happened at a very easily handled, albeit sometimes fast, speed. When the airplane lifted off at about 65 IAS, it had no tendency to sag, rock, rumba or otherwise keep you busy. I did notice, with a certain amount of delight, that I was fighting the gusts with four of the smoothest, lightest ailerons I've had the fortune to run around with. They were much, much lighter than I had anticipated. The Pitt's are a fair amount heavier and a Starduster's seem set in concrete by contrast. (Ed note: this is definitely not the case with all Skybolts)

Steen Aerolab has been experimenting with an oil-damped, spring-oleo arrangement on the Skybolt, but it may or may not be available to the public yet.

At 85-90 mph climb speed, the VSI was showing about 1000 fpm which pretty well checked with what Mickey's sweep second hand was telling me. At that rate, and considering the cool temperature, the Pitts would out climb it easily. However, this is also where the constant speed prop and extra 20 horses would make itself known. I forgot to ask Hale what the pitch was on his prop, but judging from how it reacted in later akro work, I'd guess he had a fairly coarse pitched set of blades up front.

At altitude I quickly reefed it around in a series of 90-degree turns looking for traffic. Satisfied there weren't any Wichita sheet metal surprises around, I reached into a corner with the stick and watched the Skybolt turn Jersey upside down at least once, or was it twice? The silky ailerons make any kind of roll a super sexy, kinetic affair. But that was to be expected. Out of the roll I pulled around into the first quarter of an inside rolling 360 and as I pushed it around for the negative portion of the turn, got my first hint at a problem area.

Then, I pulled the nose up, hesitated and rolled over on my back, pulling the nose through into a split-S, gaining speed for a couple of loops, some rolls on a forty-five degree up line and a few things neither one of us could identify. I can name what they were supposed to be, but there's no reason to embarrass myself.

The first thing I noticed after cavorting for a while was that the Skybolt doesn't accelerate downhill nearly as fast as the Pitts, nor does it fly away from a stalled or nearly stalled situation as well. This would be expected for a bigger airplane with less horsepower. I found it difficult sometimes to get the entry speed I wanted fast enough because I had to keep the throttle well back to keep from overspeeding the engine. That's where the constant-speed prop is a neat piece of hardware to have on board.

The Skybolt is built for bigger butts because Lamar Steen was, himself, not likely to fit into a Pitts.

At one point I was diving and, as I went through 140 mph, I figured, "What the Hell, why not?" So, I whipped it over inverted and pushed for all I was worth. I heard things starting to pop in my shoulder and that was the second hint that the elevator pressures when outside were something to be reckoned with. The airplane arced gracefully upwards in an outside push-up, but believe me, spectators couldn't appreciate the amount of muscle (of which I'm in short supply) it took to push it around.

As we leveled out and stuffed our innards back into their proper positions, Hale commented through the intercom that he had never pushed the airplane outside like that before. I was entirely satisfied with the way the airplane handled, so I naturally had to take advantage of the situation by offering to take his aerobatic virginity for him. He half turned his head to give me a dirty look, so, I explained that I believed firmly in Frank Price's famous saying "If you ain't been outside, you ain't been nowhere." He smiled (grimly) and nodded his head.

It's always a kick to take a guy around in his first outside loop from the top, especially in his own airplane. So, I throttled back and waited until the speed dipped towards 70 mph. Checking the wing tips to be sure I was level, I began the gentle push followed by rapidly increasing control movements that always occur in that downhill race for the bottom. I monitored the airspeed carefully and played the G's to give me 160 mph on the bottom. The airplane had a very, very nice acceleration rate that allowed me plenty of time to level the wings as we were tucking the nose under. It was an absolutely no sweat operation and as we streaked under the bottom, both of us being cut into small sections by the various straps holding us in, I was able to open up the arc a little and play the airplane up to the top in what felt like a reasonably round loop. Of course, anybody watching would have thought we were doing an outside egg or inverted pear or something, but it felt good and only took 3 negative G's.

I had cranked in full down trim before pushing over into the outside loop but even so the stick pressures fought me all the way around. I would have preferred to see minus 3.5 or so on the G meter when we surfaced, but as it was the stick made me feel as though we were going to get a solid minus six. Apparently this is a common gripe because Steen is reportedly changing the plans to include servoed trim tabs on the elevators as well as a quick acting trim system a la Pitts S-2.

Somewhere along the line, I was watching the speed work its way back through 115 mph when I yanked the stick back into the right corner, stomping rudder at the same time. Wham! The aforementioned snap roll suddenly got my undivided attention. I guess I've snapped as many airplanes as most folks but it's seldom that I get much of a surprise. Even so, the Steen did hand me a surprise. Without doing some measuring it's dangerous to say how fast an airplane is actually going around, but I know for a fact that the Skybolt snaps faster than a Pitts S-2 and darned near as fast as a single-hole Pitts. Even better than that, it stops where you, want it to, but you'd better decide well in advance where you want to end up.

Unfortunately, the combination of its size and fixed high prop won't let it fly away from a snap as well as I'd like. It does far better than any other two-place homebuilt I've flown (I haven't had a chance at the two-place Acroduster). Interestingly enough, the airplane snaps very well, although slower, to the left, something you just can't get a two-hole Pitts to do.

It spins extremely well and both the going-in and the coming-out are clean and crisp because of the fat rudder and the big elevators. I wasn't exactly stopping it on a dime, but with a little practice I would have figured it out. It doesn't spin any faster than most airplanes of its type, none of which is appreciably faster spinning than Cessna 150 when it's really wrapped up.

When I first laid it over on its back, I was a little disappointed, because it wants a bit more forward stick/trim than a Pitts, but a lot less than a Starduster Two (which isn't really a fair comparison). Also, even a bunch of forward trim won't take all the stick pressure off, although I'm not sure I had the trim full against the stop. A Pitts will motor along upside down all day hands off with only a little forward trim. Don't, however, construe this to mean that the Steen was running around nose high when inverted. The actual flight attitude seemed about the same as a Pitts, which is about as flat as airplanes ever fly with the pilot pointed the wrong way. Controlability and pitch stability when inverted was really excellent. There was no tendency to have to fight to maintain a given nose attitude.

As we let down towards the airport I once again reminded myself that somebody somewhere has to come up with a biplane that you can see out of. To be safe in the Skybolt (or a Pitts or a Starduster, etc.) you have to jink the nose back and forth to see anything smaller than an L-1011 that's in front of you. It is quite possible to design fuselages for bipes that let you see, although the Acroduster One is the only airplane I can think of right now that is so designed. Threading your way through the fog of airplanes that surround most airports these days is no fun in an airplane with the visibility of a timid turtle.

80-85 mph was the right number on final and I had to work a little to keep the IAS needle anywhere close because of the bumps we were punching through. A little wing down and some opposite rudder kept us lined up and I had to kill the power completely to get down where I wanted. In the same situation a Pitts or Starduster would have fallen out of the sky much faster.

Closer, closer until I could see the edges of the runway where I wanted them and I began a flair to skate gently across the invisible surface of ground effect. Feeling for the ground wasn't really necessary because the airplane seemed to naturally settle into the right attitude. All I had to do was hold it as it kissed the runway with all three. I was all eyes and nerve ends waiting for the airplane to demonstrate any bad manners it had on the runway but it appeared to have none. Its gear seemed to be just soft enough (the result of a fortunate choice of bungee cords) to absorb the landing shock without being so soft that it waddled or so hard that you skipped along rather than rolling.

A little rudder one way or the other kept things reasonably close to straight until we braked to a halt. The rollout had been disappointingly uneventful considering the wind and the reputation little biplanes have. In the same situation, a Pitts S-2 or Starduster would have me doing more of a rudder bar tango to stay on the centerline.

Does Hale Wallace like Skybolts? He must because he's building another one, this one with a (are you ready for this?) IO-540 Lycoming with 260 fire breathin' horses. That will get the power-to-weight ratio down awfully close to 6 lbs./hp, which is darned close to a single-hole Pitts' ratio. What had been a spirited airplane is going to become a flaming tiger!

The Steen Skybolt will never be able to match maneuvers with a single-hole Pitts, or a Stephens Akro. But, it's not fair to expect it to. The Steen is a two-place airplane whose role in life is to offer an upside down view of the world that can be shared with a friend. It would probably do fairly well in Akro competition up through intermediate, but it will never win. That is the domain of the single place birds. However, there is something a one-hole machine can never give its owner—the satisfaction of introducing someone else to the world of biplanes and aerobatics. And, that's what two-place machines are all about

Buying a used 'Bolt?
It's hard to know how many Skybolts have been built, but it is certainly in the hundreds. Considering that it is a huge project, as any homebuilt project is, it is "huger" by virtue of the fact that it's a biplane and a big one at that. Still, many have been finished and are offered for sale. When considering this route, remember that these are homebuilt airplanes and, unless they used major components from Steen, you have to consider the craftsmanship of the individual building it: not everyone is a Hale Wallace, in that regard. Also, make sure they followed the plans rather than getting creative, when they don't have the engineering background to know what they are doing. Also give preference to airplanes that are as close to factory specs as possible, in regards to weight. If an airplane is way under priced, if you check closely, you'll find there is a reason why and you should probably walk away from it.

Thinking About Building a Skybolt?
First, go take a cold shower. When dried off, take another one! Building an airplane, any airplane is a major project and you're looking at 3,000-4,000 hours to build a Skybolt. Minimum! Nothing about it is complicated, but there is a lot of it. No different than any other airplane its size. Buying components from Steen Aerolab increases the price, but it also increases the probability that you'll finish it.

You don't need 250 hp to make the airplane fly well, but, if using a 180-200 hp Lycoming, the airplane will fly much better if you really keep it light. Weight is almost always the result of careless application of paint and carrying around interiors and instrument panels that are far more than the airplane needs. Remember, if it's not in the airplane, it can't break and if it's not in the airplane, you don't have to lift it.



For lots more pilot reports like this one go to PILOT REPORTS