Quote from: Weaver on April 24, 2021, 12:51:11 PM
Found these extracts from contemporary articles on the Avon-Mirage here: https://www.key.aero/forum/modern-military-aviation/79024-dassault-avon-powered-mirage-iiio-prototype


Article 1 (during Le Bourget 1961)

"The civil engine being shown is the RA.29/6 turbojet of 12,725 lb. of thrust. This version of the civil Avon powers the Caravelle 6. The company is also showing an RB.146 military Avon of 12,220 lb. of thrust with a reheat system that gives it an augmented thrust of 16,000 lb. In this form the engine is installed in the Dassault Avon Mirage IIIO. The same engine also powers the latest version of the Saab Draken, but in this case it has a Swedish reheat system."

"The Avon Mirage, as we showed in a special article in our issue for Dec. 2 1960, has been developed as an export version and the 16,000 lb.s.t. (with reheat) Avon 67 engine makes it one of the most potent weapons in development in Europe. An SEPR 841 rocket pack is an optional extra to obtain optimal performance at altitudes above 60,000ft., but even without this aid the Avon Mirage takes only a fraction over six minutes to reach 50,000 ft."

Source: "The Aeroplane and Astronautics, May 25, 1961", compiled in The Aeroplane and Commercial Aviation News, 1966, pp. 586-587



Article 2 (the Dec. 2 1960 article mentioned above)

Rolls Royce Power
For export, a prototype Mirage III is being built, powered by a Rolls-Royce Avon Mk. 67 or R.B.146, which is similar to some Lightning powerplants. The R.B.146 delivers 12,500 lbs static thrust and 16000 lb. with reheat, compared to the 9370/13200 Ib. of the Atar 9B in the Mirage IIIC. With an assumed intake efficiency of 85%, the British engine will maintain 12600 Ib. thrust at M=2 and 36000 ft. Installation of the R.B.146 involves virtually no modification, and this engine has a considerably better specific fuel consumption than the Atar.

The engine compartment remains unchanged, the turbojets being almost identical in diameter except for the Avon's slimmer afterburner. The R.B.146 slides forward on the same two lateral rails for installation as the Atar, after removal of the double-skinned rear fuselage. Rear fuselage doors give additional access, although the engine continues to be reached principally through the fuselage mainwheel wells for servicing. No change in intake configuration is needed despite the 3% increase in mass flow of the Avon, except for the alteration of the shock-cone supersonic movement ratio. Weight increase with the Avon is about 640 lb., which causes a slight aft CG movement. Time for an engine change is quoted by Dassault as two hours.

As the other component of the intercepter powerplant, the SEPR 841 rocket pack is completely self-contained, with an integral 69 gal. tank for the nitric acid propellent, and a six- bolt attachment to the rear-fuselage recess. A telescopic spline-shaft picks-up via a pneumatic clutch with the separate turbojet accessory gearbox to drive the rocket pack pumps, which feed TX Furaline from a 32-gal. tank in the gun bay and the acid propellent to the combustion chamber. Rocket operation is controlled by a three-position switch in the cockpit which permits almost instantaneous election of half or full thrust (1,654 or 3,374 lb. at sea level). At full power, which reaches 3.704 Ib. at 52459 ft., there is a continuous output of 80 sec., which is naturally doubled at half-thrust.

The specific consumption of the SEPR 841, which is manufactured by Hispano-Suiza, is 0.0048 Ib./lb./sec. at sea-level, and 0.00435 at 52500 ft Through the widespread use of light-alloy parts, stainless steel being limited to the turbine and some parts of the oxidizer circuit, the unit has a total dry weight of only 452 Ib. From the maintenance viewpoint, it is cleared for 50 flights between major checks. It is jettisonable for safety in a belly landing, and when not required, is replaced by a finned fuel tank of up to 130 Imp. gal. capacity.

Source: The Aeroplane and Astronautics, Volume 99, Number 2563, Dec 2. 1960", compiled in The Aeroplane and Commercial Aviation News, 1966, pp. 709




Article 3 (exact publication details unknown)

Currently shopping in the international fighter market are Australia, Israel and Switzerland, the main contenders being the F-104, and the Mirage III of Generale Aeronautique Marcel Dassault. There is also the excellent SAAB Draken, which is something of a dark horse, except in Switzerland, where the choice has narrowed between it or the Mirage.

On purely a technical basis, the "export" Mirage III, powered by a Rolls-Royce R.B.146 turbojet, seems in a strong position. It is the only M = 2 interceptor which has shown a take-off and landing performance, with a full operational load, of less than 1,000 yd., plus a grass field capability. It is also a more recent design than the F-104, and is therefore that much further from obsolescence, the F-104 having originated from design studies in 1950, when Korea showed the need for more advanced American military aircraft."

Source: The Aeroplane and Commercial Aviation News, 1966, pp. 707

Very interesting and thanks for sharing this information Weaver.
So does this means the prototype Avon Mirage IIIO Spirit of Hobart is in fact fitted with a the

QuoteSwedish reheat system

, which if is the case, it explains the seemingly ungainly bulk at the rear of the Avon Mirage IIIO prototype, and so if fitted with the R.B.146 and British afterburn, the rear of a production Avon Mirage IIIO would be somewhat more aerodynamic, lighter, more attractive and purposeful 🤔

MAD

An Avon-Mirage may be technically "special" but visually it is not sexy, I prefer my Double-Avon Mirage:

= link http://www.kristofmeunier.fr/Mirage8_ar.jpg

The 3-surface 3-delta Mirage had no main wing, weird!

= link http://www.kristofmeunier.fr/Mirage8_as.jpg

Some Mirages were inspired by the Jumbo Jet silhouette, it seems, it was difficult for them to be supersonic:

= link http://www.kristofmeunier.fr/Mirage8_at.jpg

Quote from: Tophe on December 01, 2021, 09:33:29 AM
Some Mirages were inspired by the Jumbo Jet silhouette, it seems, it was difficult for them to be supersonic:

They just need a bigger engine, then the area ruling would be perfect

Besides, just having a rounded nose as in the first picture does not prevent a vehicle from being hypersonic even, some of the early spaceplane concepts such as Northrop HL-10, Martin X-24A, Northrop M2-F2/F3 were round-nosed because they were lifting body designs (and the Space Shuttle that was actually built had quite a round nose as well). Also, in supersonic flight regime pointed nose will produce less drag, but once speeds move up to the hypersonic range, sharp nose might just melt away whereas blunted nose will produce more drag but spreads the heat from atmospheric friction over a larger area, lowering the temperature to something more manageable.

Perhaps the first (or both) is actually a concept of a Mirage-based spaceplane with a jet engine for atmospheric flight?

Thanks a lot to have found a (good) reason for my delirium!

Thanks to comrade harp's model (nice!) and explanations (useful!) at https://www.whatifmodellers.com/index.php?topic=50051.0 here are Atar Mirages 5 with small canards on jet air intakes:

= link http://www.kristofmeunier.fr/Mirage8_au.jpg

Quote from: Tophe on December 01, 2021, 09:33:29 AM
Some Mirages were inspired by the Jumbo Jet silhouette, it seems, it was difficult for them to be supersonic:

= link http://www.kristofmeunier.fr/Mirage8_at.jpg

The top one must be the two seat side by side trainer version like the TF-102!

Quote from: Tophe on December 28, 2021, 09:32:39 PM
Thanks to comrade harp's model (nice!) and explanations (useful!) at https://www.whatifmodellers.com/index.php?topic=50051.0 here are Atar Mirages 5 with small canards on jet air intakes:

= link http://www.kristofmeunier.fr/Mirage8_au.jpg

Looking good.
How about the wiskers of the Milan?
https://www.dassault-aviation.com/en/passion/aircraft/military-dassault-aircraft/milan/

Quote from: kerick on December 28, 2021, 10:38:42 PM
The top one must be the two seat side by side trainer version like the TF-102!

Thanks doctor! So I am not crazy, that's good news!

Quote from: comrade harps on December 28, 2021, 11:54:45 PM
How about the wiskers of the Milan?
https://www.dassault-aviation.com/en/passion/aircraft/military-dassault-aircraft/milan/

Thanks for this proposal, with a whif addition of course:

= link http://www.kristofmeunier.fr/Mirage8_av.jpg

While I was surfing the Web in search of the Milan 3-view drawing, I found also the Mirage 3 NG one, and this could be the basis for another delirium

= link http://www.kristofmeunier.fr/Mirage8_aw.jpg

Quote from: Tophe on December 29, 2021, 10:53:53 AM
While I was surfing the Web in search of the Milan 3-view drawing, I found also the Mirage 3 NG one, and this could be the basis for another delirium

= link http://www.kristofmeunier.fr/Mirage8_aw.jpg

the 5VNG.

Thanks a lot!

Good, like the very top of the Mirage family...
Uh, apart of colours, I did not know what was the difference with the regular Mirage 4000 (that would be ordered by the French Navy) and I had to require Google's help. The result seems to be: mainly the 4-wheels main undercarriage is specific to this Aéronavale version, and the big height of the nose landing gear (drawing below mainly). Yes ? Or have I missed other details?
Great anyway!