The Rockwell STS
Seats seven, and bring all the luggage you want in the big compartment on top. There's even a baggage loading and unloading arm for the lazy among you. Fuel burn? Block to block fuel burn is about the same as an A36 ... an amazing MPG for such a big, multi-engine aircraft. If you can manage the high CHTs (Cylindrical Hot Tail), you're in business. The only downside is the 747 you need to get it back to your hangar. Walter Atkinson took the Space Shuttle simulator for a test flight, and filed this report.
We all dream of owning an unusual aircraft that garners respect and awe on the ramp, but this one may be the end-all. If you long to trade in the Cherokee for a bigger, roomier, multi-engine load-hauler with that Winnebago-traveler feel, forget the Twin Beech. This one has a gross weight of 4.5 million pounds and a useful load with full fuel of 90,000 pounds. If what you're looking for is maximum takeoff performance without that pesky missed approach, the Rockwell STS could be your dream come true. STS stands for Space Transportation System, and you will have the only one at the airport if you and your banker step up to the plate. If you do, you also will have the most impressive VSI on the market.
History & Basics
Any step up can be daunting and I've had more than my share of new, wonderful experiences in aviation, including a couple of big multi-engine tail draggers, but believe me, it took a few days of advanced study for this transition. The sheer size is humbling, and even though her wingspan is a full 30 feet less than the Curtis C-46 Commando or Consolidated B-24 I've flown, she's a biggun.
The STS takes off like a rocket -- Flash Gordon style; maneuvers in Earth orbit like a spacecraft -- Jules Verne style; and lands like a very crummy glider -- Brinks truck style. The production run was rather small for a company like Rockwell, producing a paltry six, delivered to a single customer. I'm not sure who their demographics expert was in deciding to market this thing, but it seems to have made sense to somebody. Enterprise, Challenger, Columbia, Discovery, Atlantis and Endeavor are the fleet. They are all named after naval ships of scientific exploration, although for some reason they never named one after the very first such vessel -- Sir Edmund Halley's Paramour. The only one to never be used past the initial testing was Enterprise, and as a result, it may be your best bet on the used-big-trigear-multi market (we do revere the low-time craft in aviation don't we?) It does need some aftermarket motors and avionics, however, as well as an orbital flight test, because it has never been above 26,000 feet. There is but a single accident report in all of their flights -- a very impressive safety record.
The production runs were sporadic, with one model produced in each of 1977, '79, '82, '83, '85 and '91. With that kind of production, one would think that maintenance and technical support would be an issue to any owner on the used market, and you would be right. Choose your model carefully and be sure and take the time to have your A&P/IA do a thorough pre-purchase inspection. These birds are getting a little long in the tooth, and even though the TT in service on the Hobbs seems low -- don't let that fool you; these can make a C-131 look like a J-3 at Annual time. The design lifetime is 100 flights. I'd suggest a progressive inspection program.
The STS consists of three major components: the orbiter, which houses the Commander (pilot), Pilot (co-pilot), crew and luggage; a large external fuel tank (ET), which holds fuel for the main engines; and two solid rocket boosters (SRBs), which provide most of the lift during the first two minutes after wheels up (which are already up when you climb aboard). All of the components are reused except for the ET, which burns up in the atmosphere after each trip around the pattern, so a good source for ETs is a must on the used market. NASA has made literally thousands of major and minor modifications to the original design, which makes it safer, more reliable, and more capable today than ever before. There is a galley for serving hot food and you won't believe the potty! There are no 337s or STCs listed in OK City, as all of the modifications are OEM; the manufacturer provides a complete list of upgrades.
Rockwell International STS
Base Sticker Price: $2B (billion) for the orbiter, give or take a buck
Add-Ons: external fuel tank, solid-rocket boosters, fuel and insurance: $5B.
The entire shuttle program yearly budget is around $6B for 6 missions, so these add-on items are probably closer to $1B. Figure on your insurance premium to be $4B or so.
Powerplants: Internal liquid-propellant rockets, 3 each
Normal = 488,800 lb of thrust each
METO = 513,250 lb each (Maximum Except Take Off -- emergency use only)
I sorta wonder what would constitute an emergency? Getting to orbit when you lose two engines late in the launch? Or losing one after the last Return To Launch Site (RTLS)?
Length: 122 ft - 2 in
Height: 56 ft - 8 in
Wingspan: 78 ft - 1 in
Wing area: 2,690 sq ft
Wing loading (landing): 95.2 lb/sq ft
Crew (minimum): 5
Crew (maximum): 7
Empty weight: 175,000 lb
Max. gross t.o. weight: 4,500,000 lb
Max. gross t.o. weight, orbiter only: 265,000 lb
Max. gross weight in on-orbit configuration: 0 lb
Max landing weight: 256,000 lb
Useful load: 90,000 lb
Still interested? Check out the performance, airspeeds, and more!
To make this one pay, leaving home with just you and the spouse is a little on the showy side. It will seat seven for a duration of 17 days from FL 5300 to FL 21000 (that's right, about 100 - 400 miles up there). That beats anything out there on the new or used market for payload and range. You will need a Multi-IFR rating to get down into Class A airspace, and then an IFR-Glider rating to get below FL500, but ratings are a mere picayune in the grand scheme of things.
In the last decade, the current owners have made engine and systems improvements that are estimated to have tripled the safety of flying the Space Shuttle, and the number of problems experienced while a shuttle is in flight has decreased by 70 percent. During the same period, the cost of operating the shuttle has decreased by one and a quarter billion dollars annually -- a reduction of more than 40 percent, and a reduction of more than a factor of 12 over the expendable Saturn-class rockets. What other multi-engine aircraft can boast operational cost decreases? At the same time, because of weight reductions and other improvements, the luggage you can carry has increased to 7.3 metric tons (8 tons). No other manufacturer can boast such improvements and savings!
For more information than your A&P/IA can digest, try the Shuttle Reference Manual.
When I arrived the aircraft had already been preflighted and was ready to go. Heck, I felt like I was an airline pilot. If you think the post-9/11 airport security is tough, let me put your mind at ease. I arrived at the Johnson Space Center and was escorted everywhere. You can't get in without an escort. Our escort was a delightful young lady from News Services, Kacy Kossum. She accompanied us to meet Col. Charles Precourt, Chief Astronaut, and Mr. Charlie Spencer, our Director of Mission Control for the flight.
The departure runway is pretty short and not very wide but since the takeoff roll is zero and the distance to clear a 50' object is zero, I wasn't too concerned. We kicked the tires and loaded up to light the fires. (That one has taken on new meaning.)
Getting into this beast is not easy. It sits vertically and the best way to prepare yourself for the entry into the cockpit is to spend a week climbing around the monkey bars at the local elementary school. You'll feel at home. All of the buttons and switches on the center console are recessed so you can step/bump into/crawl across the center console as you move around the cockpit.
Once in place, flat on your back, you adjust the seat height, back angle and rudder pedals. The five-point harness is strapped on and you begin to question your sanity. Out of my left window I can see the tower standing next to us and the Everglades to the west, both cocked 90 degrees to my flat-on-my-back position.
The radio comes alive with, "Mission Control clears SMS-1 to Canaveral via thrust vectors, Up, Hold Earth, right turns, expect further clearance in ten days."
The Terminal Count (sheeesh, I hate that description) lasts from T minus 20 minutes to SRB ignition. This is the time where you had better make sure your toothbrush is on board and you have already gone to the bathroom for the last time before flipping on the mags. After the terminal count, there's little time for afterthoughts or woulda/coulda/shouldas. I hear Mission Control advise, "Two minutes." With six seconds to go we can hear and feel the main engines fire up.
The first-stage ascent extends from SRB ignition through SRB separation and includes the sequences of major guidance, navigation, and control events. There is a lot more going on than this country boy could keep up with, and I'm thanking my lucky stars (well, I'm hoping they're lucky today) that there is an autopilot in charge because this is the point at which you feel like a 600-pound gorilla has grabbed you by the shoulders and is really, really mad. The shaking is violent. No, that's not exactly correct. It's worse. It's an 800-pound GO-rilla. I'm thinking, "This will definitely not get by the noise abatement rules at my local airport." The shaking is coming from the SRBs, where the solid fuel is burning in uneven pulses.
(Click photos for hi-res versions)
During the first 90 seconds of flight when the gorilla is his maddest, the flight control system provides load relief by making adjustments to reduce vehicle loads (mostly on the control surface hinges) at the expense of maintaining a precise trajectory profile. So much for the precise tracking outbound on the 090 radial of the Vero Beach VOR. You needn't worry, it's hard enough just to read the instruments -- the gorilla is shaking them, too. Just as thrust is approaching a critical stress on the airframe, it is automatically reduced for about 30 seconds before it is again applied at max. This has become known as the "thrust bucket." That's a good name because here's where a bucket might come in handy. No, not airsickness -- stress. Maybe "Depends" would have been a good idea; and I'm only 53.
Thrust vector control is the hub of flight control. In the ascent phase, the four ascent thrust vector control drivers are busy responding to commands from the guidance system. I'm happy about that because one particular comment in The Right Stuff comes to mind. Something about "Spam in a can."
At this point, in answer to my query, "What the hell is going on?" Col. Precourt calmly explained to me that the thrust vector control closes the acceleration and rate loops within the outer attitude loops to generate body axis attitude error rates, which eventually are nulled out by the main engines and SRBs. What this really means to Mrs. Atkinson's little boy is that we are doing one hell of an outside loop -- only we're now upside down, so it's an inside loop that doesn't feel exactly right.
First-stage guidance is active from SRB ignition through SRB separation plus four seconds. Navigation during the first stage propagates the vehicle state vector through use of inertial measurement unit data and a gravity model. Okay, this means that a guy on the ground with a bunch of pens in his pocket protector has decided where I'm going. Hey, I'm comfortable with that.
Boost guidance is a neat concept that keeps track of thrust and trajectory vectors, and if we "lose one on takeoff," the guidance automatically recognizes the failure and lofts the trajectory, commanding the remaining two engines to a higher thrust percent. I'll bet you'd like to have that on the Twin Comanche, wouldn't you?
No crew actions are planned during this phase of flight unless there is an abort. Now, that's something to think about ... but I'd rather not. Mostly what we're doing at this point is monitoring the correct pitch attitude on the attitude director indicator and altitude rate via the altitude/vertical velocity indicator at each of five designated times during first-stage ascent. ("Hey, Arlo, check out that VSI" -- or where I'm from, "Hey, y'all, watch dis!"). We are monitoring the main engines to make sure they correctly throttle down and up. We must also ensure that the Pc-50 message (SRB chamber pressure less than than 50 psi) correctly appears on the CRT display before SRB separation and that SRB separation occurs on time. In other words, we can still breathe as long as Scotty's matter-anti-matter doesn't blow ("She's holding together, Captain.") Manual intervention by the crew is required if these events are not automatically accomplished. In other words, we ain't doin' nothin', but we're really, really busy. Go figure?
In the automatic mode, flight control during first-stage ascent uses commands sent to it from guidance. Believe it or not, the guys who fly this thing can actually hand fly an acsent if they need to do so. I wanted to try one but they value the product.
(Look closely under Walt's elbow: no thrust on the right-hand column!)
We continue the ascent and the sky turns darker as we climb. "Uhh, Houston, We've got a problem!" was something I had thought about joking, but at this point it was real. At 1:45 into the flight the red lights are blinking and the alarm is sounding. (this one is not nearly as loud as the C-46 fire bell, by the way.) True to the form of every flight instructor I've ever had, Mr. Spencer back in Mission Control had killed one on take-off. "Just wait till I get back on the ground and catch up with him," I'm thinking. The engine control display confirms #3 has shut down. ("What happened to all that matter-anti-matter, Scotty?") The vector control system has already sensed the failure and has pushed our trajectory higher. We must do three things if we are not to swim back to the Cape. First we have to let the SRBs burn out and get rid of them -- that's going to take another 24 seconds. Then we have to slow down, stop, and "re-thrust" back toward Canaveral (you read that right), and just as important, we must get rid of all that fuel in the main tank before we can jettison it.
While looking up the engine failure checklist and flipping to the RTLS page (Return To Launch Site), the next major event is SRB separation, which occurs six seconds after sensors detect both SRB chamber pressures below 50 psi and about 2:09 into the flight. In other words, we're out of nitro at the drag strip. There is a flash, a jolt, and away they fall as the flight becomes silky smooth. The main engines are as smooth as electric motors and the change is welcome. I can see the SRB on my side arc away from us. Usually this is an automatic action but it can be done manually by flipping the switch to manual and pressing the SRB sep button. Flip a switch, punch the button and boom go the SRBs. I wanted to do that, too, but they value the product.
Here's the point where Col. Precourt asked me, "How are your aerobatic skills?" I guess my blank stare was answer enough. "We've got to swing us around, tail first," he says as he points over his shoulder and adds, "the Cape's back that way." As soon as the ET is down to 40% fuel, we start the flip-flop. For all you aerobatic guys, this was a piece of cake... the computer did it.
With the tail pointing first we are continuing to rise toward Europe and the remaining two engines are slowing us down. We reach an apogee at about 225,000 feet and we begin to descend -- much like a Brinks truck. Thankfully, the VSI looks fairly normal. I check it and we show about 1000 down ... Oh wait, that's 1000 feet per second! Sheesh! Our path toward Europe stops as we fall to about 180,000 feet. The engines are still pushing, this time westward and back up! The AI shows 50 degrees nose up.
After a few more seconds, I can hear the main engines throttling down. "Thank you for your service." As soon as the main engine shutdown is confirmed, ET separation begins and the retraction of the 17-inch disconnects within the orbiter aft fuselage is accomplished. How's that for fuel line size? Some other stuff happens really fast, and the ET separation is performed automatically. Another "boom and jolt." This time instead of falling into the Indian Ocean or the Pacific, the huge tank will end up very nearly where we left the SRBs.
"Please be seated, fasten your seat belts, and be sure that your seats and tray tables are in their full up-right and locked position." Basically that's what's going on in preparation for the upcoming E-ticket ride back. We are coasting quietly back toward the Cape somewhat like a manhole cover falling on edge. Glide control is through roll. If you're level, your sink rate is the least; as you increase bank angle, the descent steepens. OK, I've got that.
The orbiter attains subsonic velocity at an altitude of approximately 49,000 feet about 22 nm from the runway. How's that for a pattern altitude? "Lieutenant, enter the pattern at 49,000 feet, descending."
Col. Precourt was bound to get a sinking feeling in his stomach as we hear the computer say, "Manual Stick Control Engaged." Aarrrgh! I am flying this thing -- by hand! His calm voice begins to explain how to line up the trajectory vector diamond in the nav control box. He further explains, "keep those in line with the two sets of carrots" and I think, "they're off and running at Hialea!" Hey, nothing for a Sky-pilot, right? He asks if I can see anything yet?
"Yes, there's Andros Island and Miami further off to our left," I answer.
"That's a good sign," he encourages me. "Now don't look away again ... remember, a 360 will cost us 38,000 feet and you only have 35,000 left." ("Hmmmm? When he started that sentence we were at 49,000.")
The HUD is really neat. All of the info you need is right there. Air speed, Alt., Nav data, VSI, and even the runway centerline shows up on the HUD (not bad for something designed 30 years ago). You can toggle through the HUD to have it display as much or as little information as you are comfortable looking at. At 35,000 feet, we are basically on the downwind. The approach is not a square pattern but a circle to land around a point offset from the runway. As you circle, the runway will line up. The Final Approach Fix is 6.9 miles from the touchdown zone, and you are at 10,000 feet.
O.K., sports fans, we're talking about an ILS with an initial glide slope capture at the final approach fix at 10,000 feet, at 290 knots, and 6.9 nm from the runway. The glide slope angle is -20 degrees (nothing like the -3 degrees you've become accustomed to) and is aiming at a point 1.5-nm short of the runway. The descent rate is about 11,000 feet per minute (200 fps). "Wow, look at that VSI." Nothing for a sky-pilot, right? At approximately 1,750 feet AGL, a preflare maneuver is started to position the orbiter on a shallow 1.5-degree glide slope in preparation for landing (and to eat up that last mile to the runway). "Gear down, please, Colonel." A gear-up at the Cape would be incredibly bad form -- ten demerits.
The final flare is begun at approximately 80 feet to reduce the sink rate to less than 9 feet per second. This is done by bringing the force vector in the HUD up to the horizon. Duhhhhh, we do want to stop going down as the wheels touch, right? To over-rotate here would be very bad. A quick pitch rotation around the CG would push the aft-mounted main wheels down toward the concrete too quickly, so think "eggs" on the pitch control as you get close. The landing attitude is maintained and I feel the mains as they screech on. We hit a little harder than I thought we would, and then the chute was deployed. As we slow, full down trim is applied to the trim button and the nose gear slaps down. At that point brakes are applied and the chute is cut loose so it stays behind the Spacecraft.
The Shuttle has toe brakes and nose gear steering like most GA aircraft with a minor difference: you don't have to hold the brakes after you stop and you are not taxiing back to the hangar.
The ride wasn't over. Mission Control (actually, this is the "Instructor Station" in NASA parlance -- Mission Control is the real deal on the other side of Johnson Space Center) gave me two more high-altitude approaches, starting at 50,000 feet. The one we had just completed after the aborted launch touched down with a vertical velocity of -7 fps (-9 is max), slightly off the centerline. The second was much better, with the centerline between the mains (ATP standards) with a sink rate of -6 fps, and we didn't hit the concrete quite as hard. As with most any aircraft, flying the numbers are the key to a good landing. On the third landing, I kept the trajectory vector in the Nav box during the entire approach, and the landing was dead on the centerline with a touchdown of -1 fps -- a true greaser. In the video of the last landing you can hear one main tire screech, then the next, then the nose gear without any bouncing. "It felt good," is a ridiculous understatement.
-- Walter Atkinson
Special thanks to Colonel Charles Precourt, Mr. Charlie Spencer, and Ms. Kacy Kossum of NASA, and most especially to Dr. Jay Apt, former NASA Astronaut and my dear friend, for making this one of the most exciting and mind-expanding days of my flying career.
Walter Atkinson is a contributing author and a practicing general dentist in Baton Rouge. He has over 3000 flight hours and holds the ATP-multi and a Commercial with SEL, MES, and SES ratings. He also holds instrument- and multi-instructor certificates and is an A&P. Walter and his wife, Pat, have owned a J-3 and an aerobatic Bonanza, and currently own and fly a C45H Twin Beech. He has time in C-47, C-46, and B-24 warbirds. He has authored both historical and humorous novels, and has been published in both aviation and dental journals.