Nord Griffon

[Archibald]

Thread to discuss operational variants of the mighty Griffon turboramjet-powered aircraft of the late 50's.
Some pics from "prototypes.com" (no longer updated since two years   )
http://jpcolliat.free.fr/griffon/images/griffon_12.jpg

http://jpcolliat.free.fr/griffon/images/griffon_16.jpg
http://jpcolliat.free.fr/griffon/images/gr...griffon_16b.jpg

These two are mach 3 variant made of stainless steel. The first is a straightforward derivative of the Griffon, the second is a fallback in case of failure, taking its inspiration from the CT-41 target drone.

The plane had an Atar -101 housed in a bigger ramjet, and the system worked rather well. The plane reached mach 2 three days after the Mirage IIIA, on 27th october 1958.

Enlarged radome and R-530 underwings, drop tanks (fuel consumption was a bit high).

Better engine (british design, olympus for an enlarged variant, this would give a
F-103 - like machine).

British variant with Avon to replace F-155T circa 1959 ?
ADC / F-106 markings ? 318th FIS    

Cranked wing ala Drakken ?

Tailed delta ? T-tail (this would please Baz)

[dy031101]

Guess you beat me to it.  

Is the Super Griffon a single- or two-seater?

British variant with Avon to replace F-155T circa 1959 ?

I was wondering how cool it would have looked if Hawker worked with Nord to modify their P.1103 design with tailess delta wing and the mixed-power propulsion scheme......    

[Archibald]

The three are single-seaters.

What an idea! P.1121 / Griffon kitbash ...    

[dy031101]

P.1121 / Griffon kitbash ...

Hehe, my thought exactly.

Actually a two-seater would be stand more of a chance for F.155T...... which is why I mentioned P.1103.

But of course, P.1121 forward fuselage could perhaps be turned into one for P.1103 with modification.

[elmayerle]

And for those looking for v/stol efforts, I've seen drawings of a tail-sitter version of the Griffon.  *wicked chuckle* I think the Merlin kit might be perfect for modelling that one.

[dy031101]

Speaking of kitbashing...... how about a Eurofighter Typhoon (or BAe EAP, if a kit for it is available) with Griffon propulsion scheme?

[Maverick]

I've always thought the post war French experimentals were bloody good looking ships, (Griffon, Gerfaut, Baroudeur, Leduc, et al.) and love 'em or loathe 'em Mach 2 has seen fit to kit quite a large number of the aircraft.

Mav

[Archibald]

I've always thought the post war French experimentals were bloody good looking ships, (Griffon, Gerfaut, Baroudeur, Leduc, et al.) and love 'em or loathe 'em Mach 2 has seen fit to kit quite a large number of the aircraft.

Mav

Mav', can I hope  to see some two-seat Griffon interceptors in the next future ? Wink wink...

If you want some nice profiles of french types/ projects Maverick, drop me a mail...

[dy031101]

After some browsing through the Wikipedia, I still feel unclear as to the differences between the ramjet-Atar combo of the Griffon and Pratt & Whitney J58 of the SR-71...... or if they are any different at all in terms of arrangement schemes......

Any clarification would be greatly appreciated......

[Archibald]

Ok, here's a try.

Griffon/ Leduc engine were basically large-diameter ramjets with a small turbojet inside.
It was found that the Atar resisted quite well to heat and flow of the ramjet surrounding it.

J-58 was another matter.

From what I've understand, the huge shock cone you can see in the intake masked the front fan/compressor at mach 3.

It seems the cone moved backward as speed rose.

Thus the J-58 sucked its air
- via side intakes,
- via the small interstice left between the engine nacelle and the shock cone.

Then the combustion chamber+afterburner were used as a ramjet !

In short
- the front compressor was masked/ protected by the shock cone
- thus it was simply bypassed after mach 3, because the fan could't resist mach 3 speeds
- So the engine had to suck its air avoiding the compressor;
- thus the compressor/ fan part of the J-58 was not used,
- leaving only the combustion chamber and reheat at work; well, that's a ramjet!

At mach 3 around 80 - 90% of the thrust came from the combustion chamber/reheat rather than the compressor; the J-58 was no longer a turbojet but a ramjet.

Btw when the J-58 was extracted of the SR-71 engine nacelle for maintenance, it was nothing more than an Olympus or J-75-like engine.
The "ramjet part" of the J-58 laid in the intake and nacelles, not in the engine itself.

Hope it's clear enough.

[Jeffry Fontaine]

Google Image Search Results for J58
Google Search Results for J58

Archibald,

The J58 was a very complicated engine and it was kept under wraps for a very long time as to what it really looked like.  Now that the aircraft has been retired you can see the engines in some aviation museums.  The Seattle Museum of Flight has an M12 Ox Cart on display with a J58 displayed near it.  Some of the images in the search link above will give you a good idea of what the engine looks like without the aircraft attached to it.

The moving shock cone design was not new.  A slightly less complicated shock cone was used on the J79 engines that powered the B-58 Hustler.

Here is a good diagram from Wikipedia that shows the shock cone operation in some detail (note that this page was originally part of a classified technical manual on the SR-71).  Thanks to the general declassification schedule it is now available for viewing by normal people. 

[dy031101]

In anticipation of having some time to spare next week, I started modelling the Ramjet Typhoon in 3D Studio Max.

(Only got the external shape of the "barrel" that is supposed to house the intake and the engines done so far......)

I don't know how it looks like if I look into the Griffon's jet exhaust though.  Does anyone have a picture?

[ElectrikBlue]

In anticipation of having some time to spare next week, I started modelling the Ramjet Typhoon in 3D Studio Max.
(Only got the external shape of the "barrel" that is supposed to house the intake and the engines done so far......)
I don't know how it looks like if I look into the Griffon's jet exhaust though.  Does anyone have a picture?

This may help!

[dy031101]

Will see what I can make out of it.  Thanks.