Between the first and second world wars, aircraft development was moving apace in Europe. One of the many people pushing aircraft technology was Alexander Lippisch, the designer of the rocket powered Messerschmitt Me 163 Komet.
Lippisch proposed a triangular delta wing would reduce drag and increase lift, while its shape would make it inherently strong. At the end of WW2, Lippisch and a delta-wing glider fell in Allied hands and were transferred to the US.
Consolidated-Vultee, adapted Lippisch’s ideas into the XF-92A which took to the skies in 1948. The aircraft wasn’t the easiest to fly (later pilot by Scott Crossfield remarked “It was a miserable flying beast”). As a consequence the Consolidated civilian pilots expanded the aircraft’s envelope with painful slowness.
After a year the aircraft had only been taken to 0.85 Mach and the frustrated USAF took over flight test. Specifically, they handed it to Chuck Yeager.
Yeager agreed that the aircraft was tricky to fly, but he still pushed the aircraft to Mach 1.05 on his second flight.
More amazing were the landing characteristics. In Consolidated’s hands they had only brought the landing speed “down” to 170mph.
On that second flight Yeager decided he could do better. As he approach the Muroc lakebed he pulled back on the stick.The aircraft slowed so he pulled back further, bringing the nose up and gaining more lift from the wings. To his amazement he kept pulling back on the stick until he was at 45 degrees angle of attack, and landed at a mere 67mph – a full hundred miles an hour slower than Consolidated had achieved in a years development.
A 45 degree angle of attack means the aircraft was moving roughly horizontally through the air while the nose was pointing up by 45 degrees. At that angle he would have had no forward visibility and landed on his peripheral vision alone. Quite apart from the courage it must take to balance several tons of metal and fuel a few feet above the ground at such extremes, its got to take a massive amount of skill and experience to feel when the aircraft was at its limits and know when to stop using angle of attack to keep the aircraft airborne.
Consolidated-Vultee put out a promotional video, complete with a formal voiceover, describing the XF-92A’s benefits.
Those slippery characteristics that allowed Yeager to perform his landing feat were to catch another pilot out. After the aircraft was handed over to NACA, Scott Crossfield took the aircraft out on the Muroc lakebed for a taxi test. He’d been briefed on the aircraft’s tendency to roll a long way, but during the run he let the nose of the aircraft come down. The aircraft was now rolling on all three wheels, wings level, the minimum drag configuration. The aircraft kept rolling. He tried to bring up the power but couldn’t get the nose wheel up (and hence be able to use the drag from the wings for braking). The edge of the lakebed loomed. He had no choice but to use the wheel brakes, even though he knew he was going too fast. In his last few moments on the lake he spotted a country road and steered for it. In a cloud of dust, the aircraft bumped up the road a good hundred yards. When he came to a stop the brakes were gone, completely melted. Inevitably the road became know as the “Crossfield Pike.”
The XF-92A wasn’t loved, but it did prove the viability of delta wings. Today the US uses variations on the delta wing concept in aircraft such as the F-15 and F-22, but it is the Europeans who have gone back to Lippisch’s original idea with the current Dassault Rafale and the Eurofighter Typhoon.
The XF-92A has one last story up its sleeve, but I’m going to keep it there until next week 🙂
Yikes. Great post.
In imagining Crossfield”s road trip I had a strong sense of “Oh $#@*”. I am usually up for road trips and as long as we are well equipped for contingencies I’m happy to not have a schedule but I specifically avoid juiced jet fuels on dirt roads…or any road…or a hangar. In the spirit of cooperation and because at times it’s just too far to walk I tolerate flight and I prefer it to be uneventful.
I’m always grateful that people like Crossfield, Yeager, Glenn,Shepard et al have been willing to work out these nasty little details of flight without directly involving me in any of it. I survived my childhood enthusiasm for unmanned flight so I’m happy to quit while I’m ahead of the game.
Your series concerning things that leave the ground is very enjoyable. Eventually I would still like to see a book from you on automobiles. Maybe you could combine flight and water and just select out the hundred most interesting designs or fifty designs or whatever makes sense.
You state a preference for fiction and perhaps you will produce great fiction. I would be your least valuable fiction critic. I suspect that you could very easily write a great book about odd transportation devices.
If you do I will send an advance check for an early autographed copies for my dad, my two sons, two of my brothers-in-law, Piper Bayard’s son and myself. My small order hardly constitutes a best seller but I suspect that I am not your only potential customer.
Hi Holmes. Back from the Swiss chocolate eating competition ok, I hope.
I share your gratitude towards people who are prepared to brave the unknown (or Ughknown as Yeager called it). There is an old adage that says “don’t fly in the A-model of anything.” I sit quite happily in Bs, Cs, and Ds, comfortable in the knowledge that they’ve been doing it successfully for some time. Well, comfortable in knowledge and those tiny bottles that the stewards/stewardess bring round.
A book on automobiles combining flight and water? That pretty much covers all the bases. Who knows, perhaps by the end of this year I’ll have enough material. Though if it’s the end of this year I fear you won’t be able to get an autographed copy of any book, it’ll all be electronic by then. Rest assured though, if I do manage to publish anything you’ll be receiving a box full, or perhaps I should say an email with a link to a download.