Charles « Chuck » YEAGER – 71 years ago !


Supersonic aircraft X-1 in flight
Photo: NASA

Captain Charles « Chuck » YEAGER broke the sound barrier with the help of his friend Jack RIDLEY on a 14th of October 1947 – He did it 71 years ago!

Brigadier General Charles Chuck Yeager next to his X-1 aircraft

(U. S. Air Force illustration/Mike Carabajal)

Supersonic aircraft X-1
Photo: NASA

Supersonic aircraft X-1 pre-flight inspection

Photo: U.S.Air Force Link


Birth of Manned Rocket Research Airplanes: 1946 to 1975

The first reliable, effective rocket engine that would provide boost for experimental research aircraft was produced by four members of the American Rocket Society (ARS) who combined forces to form Reaction Motors Incorporated (RMI) (Rockaway, New Jersey) for developing the Experimental Liquid Rocket (XLR-11) rocket motor. The XLR-11 engine had four separate rocket chambers. Each chamber provided 1500 lb of rated thrust and could be operated independently as a means of throttling thrust in quarters, up to 6000 pounds. The XLR-11 possessed remarkable longevity, powering an impressive fleet of rocket aircraft for more than a quarter of a century (1946 to 1975). This fleet of vehicles were the first rocket aircraft devoted solely to high performance experimental flight research. They were not constrained by military or commercial demands and ranged from being the first to break the sound barrier (XS-1), to the first to reach Mach 2.0 (D-558-II [fig. 5]), to the first to exceed the X-2 Mach 3.2 record (X-15 with two XLR-11 engines).

D-558-II airplane on Rogers lakebed

Figure 5. The D-558-II airplane on Rogers lakebed.

The X-1E – Early Development of Energy Management

Design efforts to extend aircraft performance produced increased wing loadings, W/S, and decreased lift-to-drag ratios, L/D. These design changes were beneficial in reducing drag to achieve supersonic and hypersonic speeds, but were also detrimental in that they reduced the area of the maneuvering footprint and presented difficulties in the approach and landing.

As L/D values decreased, the glide slope angle and the rate of descent increased, making it more difficult for pilots to estimate distances and times required for acceptable landings. The X-1E (fig. 6) was modified with a low-aspect-ratio wing having a thickness-to-chord ratio of four percent – the only aircraft of the X-1/D-558 series to have sufficiently low L/D values to require unique energy management techniques. This X-1E was the first to experiment with approach patterns designed to give
the pilot more time in the traffic pattern to manage energy.

The landing pattern was approached in a conventional manner except that altitudes and speeds were somewhat higher than for
powered aircraft. The initial reference point was established at 12,000 ft (mean sea level) on a downwind heading (180 deg remaining to turn). The downwind leg was offset some four miles from the centerline of the landing runway. On downwind, abeam the touchdown point, landing gear and partial flaps were deployed at a speed of 240 knots. Full flaps were usually deployed on the final approach. At the initial reference point the pilot had almost three minutes until touchdown – additional time for handling increased speeds and sink rates.7,8

X-1 supersonic aircraft on Lakebed

Figure 6. The X-1E airplane on Rogers lakebed.

X-1E supersonic aircraft under B-29 Mothership

Secret declassified USAF pilot Charles Chuck Yeager after breaking the sound barrier on X-1

Report from

X-1 supersonic aircraft instrument panel

(Text from the NASA at:



I had already written about that in my book UNE AUTRE HISTOIRE DE L’AVIATION, on pages 12; 13; 71; and others – Bernoulli’s principle does not explain everything. We know that aircraft fly. Strange as it may seem, Bernoulli’s principle has often been taught for decades as the explanation of the phenomenon.

Je l’avais déjà évoqué dans mon livre « Une autre histoire de l’aviation » aux pages 12, 13, 71, et d’autres: Le théorème de Bernoulli n’explique pas tout. Nous savons que les avions volent. Depuis des décennies, aussi bizarre que cela puisse paraître, on enseigne souvent le théorème de Bernoulli comme l’explication principale au phénomène.

This explanation would make sense if the air particles split at the leading edge of the wing and come together at the trailing edge. However, Cambridge researchers had debunked this flying myth in 2012, and have recently confirmed that Bernoulli’s principle cannot explain everything in wing lift. As you can see on the video above, the upper wing air stream travels much faster than the lower wing one. Last but not least, these air streams do not come together at the trailing edge since the upper wing air stream reaches the trailing edge well before the lower wing airflow. Isn’t this amazing?

Cette explication tiendrait si les particules d’air se séparaient au bord d’attaque de l’aile et se rejoignaient au bord de fuite. Cependant, des chercheurs de Cambridge avaient démonté ce mythe du vol en 2012 et viennent de confirmer que le principe de de Bernoulli ne peut pas tout expliquer dans la portance de l’aile. Comme vous pouvez le voir sur la vidéo ci-dessus, le flux d’air en extrados voyage beaucoup plus vite que celui d’intrados. Enfin et surtout, ces flux d’air ne se rejoignent pas au bord de fuite puisque le flux d’air d’extrados atteint le bord de fuite bien avant le flux d’intrados. Étonnant, n’est-ce pas?



GREAT VIDEO – Watch for pleasure, first. Listen carefully to the figures and phrases uttered and compare with the various texts that are enforced in the world, and in Europe. In such an extreme situation, you may understand that the procedures are turned into a faster phraseology. So, why not adopt it in GAT (General Air Traffic), after all? 😉

SUPERBE VIDÉO: Regardez d’abord pour le plaisir. Écoutez attentivement les chiffres et expressions et comparez les avec les textes en vigueur dans le monde et en Europe. Dans une situation aussi extrême, on peut comprendre que les procédures se fassent plus rapidement dans la phraséologie. Alors pourquoi ne pas l’adopter dans la CAG (Circulation Aérienne Générale), après tout? 😉


Mach-3 SR-71 Blackbird’s HOT COCKPIT

Blackbird onboard USS Intrepid – Photo © Xavier Cotton

As you may have heard, the mythical Lockheed SR-71 Blackbird was a strategic reconnaissance aircraft able to fly at more than Mach 3 – Mach 3.3 ie around 3,500 km/h; or 1,900 kts; and at a maximum flight level of… FL 850 or 26 kilometers high!

The Blackbird indeed had a unique flight envelope with a particular doghouse plot (since she could not exceed 3.5 G), and an exceptionnal coffin corner limited by her CIT – Compressor Inlet Temperature of 427°C maximum.

This aircraft was also unique for her engines were two J58 ramjets fuelled by JP-7 especially refined for extreme flying purpose. This special fuel could drip and leak abundantly as the airframe made up of titanium was retracted while taxiing, and became airtight only when it got its operating shape while flying very fast and very high because of the air density, and surrounding pressure plus the heating caused by the air friction at such speeds. In short, the whole structure considerably expanded when airborne.

The irony – I heard it on the grapevine, or read it somewhere on the web – that titanium which turned into dark blue while flying (SR-71s probably deserved those unofficial other nicknames « Bluebird », or « Habu » viper) was « imported » from… USSR!

Pilots must have taken significant risks inherent in flying such an aircraft as mentioned in this previous post. These pilots used to fly over the USSR to take strategic reconnaissance photographs during the Cold war. They wore pressurized spacesuits so that their blood could not boil in case of decompression or ejection at such altitudes.

The Blackbird travelled faster than a rifle bullet, and the air friction could have melt aluminum-skinned aircraft. At Mach 3.2, fuel cycled behind the chine surface in order to cool the aircraft! The inner windshield temperature could reach 120°C even though a heavy-duty cooling system was on a full function. On landing, the outside temperature of the canopy could reach 300°C, and it must have been far beyond on the fuselage, and wing surfaces while flying at high speeds. The pilot could feel the heat behind his protective gloves!

Special thanks to Xavier Cotton for the Blackbird photos. Please, visit his website on



Felix Baumgartner, the famous Austrian skydiver, is still waiting for better meteorological conditions to make a new attempt in the Red Bull Stratos project to break the sound barrier while freefalling. This new feat might happen within the next few days as it has already been scheduled on October 14.

According to the video below, Felix BAUMGARTNER’s top 5 jumps are:

  1. Wingsuit Channel Crossing
  2. Taipei 101 BASE Jump
  3. Petronas Towers BASE Jump
  4. Seating of the Spirits Cave Jump
  5. Man vs. Plane


Felix BAUMGARTNER was to jump on the 9th of October 2012. However, this jump which could have become the highest skydive in the aerospace history has been put off due to gusty winds.

In this new record attempt Felix BAUMGARTNER will be so high up – 120,000 ft, or 36.6 km – that if his suit leaks, his blood will boil. When he jumps, he will fall so fast that he will break the sound barrier as explained in this video:



A 3-hour ascent is expected to reach such an altitude, and it could take him more than a quarter of an hour to fall down back to the earth, and land… And now the animation on how it could unfold from the stratosphere right over Roswell, New Mexico, USA: (Click on the link below – MUST SEE!)