Orenda Iroquois Single Engine Fighter application theory

I

ItalianAFDFail

ACCESS: Restricted
Joined
10 January 2021
Messages
47
Reaction score
69
Good Afternoon everyone, hope you are all doing well
Lately i have been having a lot of thoughts about engine capabilities and i thought long and hard in regards to Orenda and other smaller engine manifacturers of the 50s and 60s, i thought about the Iroquois engine a lot and not only because of the Arrow project but also it's potential for other fighter applications, more specifically for a single engine design for either an interceptor or a fully fledged fighter for use by nations that phisically cannot afford something like the arrow but would have been more than willing to pay top dollar for the engines to use in their fighter aircraft, regardless of the likelyhood of this occourance i would like to ask you how designers of the era would utilize the engines for their aircraft, i don't have a lot of insight about the engine itself and how good it would be or not be in a single engine design but i hoped the forum could help in this and also what ideas the era's designers could come up with, i had some ideas myself to use it in a speculative design but i hoped this would be interesting.

I hope the thread isn't incorrect and i apologize for possible spelling mistakes
 
ItalianAFDFail said:
i thought about the Iroquois engine a lot and not only because of the Arrow project but also it's potential for other fighter applications, more specifically for a single engine design for either an interceptor or a fully fledged fighter for use by nations that phisically cannot afford something like the arrow
Click to expand...
Hm. The Iroquois looks a bit too heavy and overpowered for a single-engine fighter. It's weight is over two tons, and it's fuel consumption is rather high. Not to mention that it is rather costly due to use of cutting age alloys. Hardly an engine that third-world or even second-world customers would like.
 
I'd look at what the J75 was used for, and go from there. The Iroquois is in the same weight and thrust class as the J75, hence why the early Arrow prototypes used it. Other contemporary engines in this class were the advanced Olympus variants, the Gyron, and the RB.122.

Put another way, a single-engine Iroquois fighter would look a lot like the F-105, F-106, and Viggen.
 
the idea for me was mostly the use of the engine by some nations alligned with NATO or similarly equipped like Spain, France, Italy, maybe Sweden and maybe even Germany
 
Archibald said:
Well, before the CF-105 project was the CF-104/1, circa 1952-53. It looked very much like a F-106. Can't remember whether the PS.13 Iroquois was on the drawing board back then.
Click to expand...
Was Treasury Board willing to finance a CF-104/1 single-seat, delta-winged fighter made by Avro of Canada?
 
Last edited:
Archibald said:
Well, before the CF-105 project was the CF-104/1, circa 1952-53. It looked very much like a F-106. Can't remember whether the PS.13 Iroquois was on the drawing board back then.
Click to expand...

Both the single-engined C104/1 and twin-engined C104/2 were planned with Orenda TR.9 Waconda engine. Back-up engine type was the Bristol BOl.3 Olympus (or its Curtiss-Wright J67 copy).

TR.9 development ended later in 1953, having been eclipsed by the P.S.13 Super Orenda ... which matures into the P.S.13 Iroquois (replacing the Rolls-Royce RB.106 in Avro Canada planned C105).
 
riggerrob said:
Was Treasury Board willing to finance a CF-104/! single-seat, delta-winged fighter made by Avro of Canada?
Click to expand...

We'll never know ... because the RCAF chose to write its AIR 7-3 requirement around the twin-engined C105 proposal.

Since we're in the AltHist section, we can image a scenario where the AIR 7-3 requirement is abandoned for a more economical CF-100 interceptor replacement - a budget CF-105, if you will. Then, a developed C104/1 with maximum commonality with the CF-105 might have a chance as a dedicated Sabre replacement.
 
apparition13 said:
I'm pretty sure I've said this before, but it would work well in the F8U-3 Super Crusader. The planned upgrades to the engine would take the thrust above 1:1 for the aircraft.
Click to expand...

Sure, and pretty much anything else powered by a reheated J75 - so F-105, F-106, or YF-107.

Ditto for anything powered by a Rolls-Royce Olympus/Wright J76.
 
As apparition said, stuff an Iroquois inside the F8U3 and you'd have a winner. Of course, under the assumption that the Cru3 won over the Phantom, in the first place. And the titanium build would sell well, I believe. Durability and resistance to weather.

Still, mass-producing titanium turbines would be a hassle. Maybe it could have displaced some of the material resources needed for the Blackbird and Oxcart. Maybe a steel version would have been developed. And how about the viability of the J75 later on? Remember, NIH and domestic industry first.
Could PW push the FT4 as a matured naval GT design to compensate for their aero division losses? Mass influx of FT4-powered Knoxes/Brookes by 1970 eliminating OHP entirely would have a massive consequence on the fleet composition.
 
Last edited:
apparition13 said:
I'm pretty sure I've said this before, but it would work well in the F8U-3 Super Crusader. The planned upgrades to the engine would take the thrust above 1:1 for the aircraft.
Click to expand...
Yowza, that would be a spicy plane for the 1960s! (where's the "mind blown" emoji on this forum?)

Let's go ahead and run with the Twosader version, for reduced pilot workload.
 
Some further pondering on my part

A 2-seater Cru3, pulling circles around ( and utterly embarrasing) Phantoms, could have almost certainly been adopted. Mind you though, regardless of whatever it would have become, a Cru3 is always an air superiority beast with meager ATS capability at best. The Phantom, meanwhile, could always lug around a boatload of bombs, tanks AND Sparrows/Sidewinders. I'm thinking of giving the Cru3 a fixed supercritical wing, plumbed and wired, with hardpoints pulled from an A-7, and a side-by-side seating arrangement. How does all of that, powered by an uprated Iroquois sound? Still, something has to be done wrt the AOA issues that the variable-incidence wing previously addressed. Maybe some novel lifting surfaces or thrust management?

And now the fleet impact:
  • With no J79 orders from the Navy, PW gets aggresive and lobbies hard for the Super Tiger-J79 pairing. Throwback to the Super Cru/Tiger thread!
  • Would Vought still win VA(L) in this TL? If not, who else? Or could the adoption of a multirole supersonic Super Tiger eventually supplant the A-4 (and hence, VAL)?
  • The Cru3 could be anything but a proper Missileer. In this TL, knowing the Cru3's outstanding performance, would there be the greater drive to make VFAX more dogfight-able that OTL had? Or would something in the vein of F-111B remerge, centered on BARCAP endurance, speed to intercept point and the AWG-9/Phoenix pairing?
  • Already mentioned above is my idea of earlier GT ships for the USN, in the form of FT4-powered Knoxes/Brookes, though most probable is the Hamilton-class, which is already serving by 1967. GE picks up the challenge and offers a TF39 based design. With two competing naval GTs coming right up, there would be alot of prospect for small carriers, C14, and earlier DX/DXG. An earlier switch to GTs would also have a massive effect on older, steam ships like the Leahys and WW2 cruisers/FRAMcans. Eventual fossile fuel GT powered CSGs, CVLs and LHAs later on is a though-provoking prospect. Additionally, adopting Cru3 and old Cru's training regime could lead to a more successful USN air campaign over Vietnam, which could lead to more budget for the navy. Could we see accelerated SS(B)N and surface ship production in that scenario?
 
asVAL said:
Some further pondering on my part

A 2-seater Cru3, pulling circles around ( and utterly embarrasing) Phantoms, could have almost certainly been adopted. Mind you though, regardless of whatever it would have become, a Cru3 is always an air superiority beast with meager ATS capability at best. The Phantom, meanwhile, could always lug around a boatload of bombs, tanks AND Sparrows/Sidewinders. I'm thinking of giving the Cru3 a fixed supercritical wing, plumbed and wired, with hardpoints pulled from an A-7, and a side-by-side seating arrangement. How does all of that, powered by an uprated Iroquois sound? Still, something has to be done wrt the AOA issues that the variable-incidence wing previously addressed. Maybe some novel lifting surfaces or thrust management?
Click to expand...
Side by side would cause a real performance hit as could be seen in the TF-102 vs. the F-102. Besides, Vought had already started looking into a tandem two seat model. And the only think holding the Cru3 back as an attack aircraft was a lack of pylons, which is a comparatively easy fix. Removing the VI wing mechanism would help with weight and complexity, but I'm not sure how carrier operations could be preserved without it. A taller nosewheel would need taller main gear to maintain deck clearance, so it might not end up worth it.
asVAL said:
And now the fleet impact:
  • With no J79 orders from the Navy, PW gets aggresive and lobbies hard for the Super Tiger-J79 pairing. Throwback to the Super Cru/Tiger thread!
Click to expand...
J79 is GE, but
asVAL said:
  • Would Vought still win VA(L) in this TL? If not, who else? Or could the adoption of a multirole supersonic Super Tiger eventually supplant the A-4 (and hence, VAL)?
Click to expand...
I like this idea, as evidenced in the F8U-3/Super Tiger thread. Although the F11F-2 wouldn't have the bomb load of the A-7.
asVAL said:
  • The Cru3 could be anything but a proper Missileer. In this TL, knowing the Cru3's outstanding performance, would there be the greater drive to make VFAX more dogfight-able that OTL had? Or would something in the vein of F-111B remerge, centered on BARCAP endurance, speed to intercept point and the AWG-9/Phoenix pairing?
Click to expand...
The advanced crusader mentioned in Thomson's book carried two Eagle class missiles. If you add wind pylons, it could carry more, and fuel tanks as well. I don't know if it would have the time on station to be effective in the role, but the F-14 and F-111B were both under two hours whereas the Missileer was around four hours on station. The only thing that could really do the missileer job was the Missileer. Everything else had too little time on station or needed constant tanker support.
asVAL said:
  • Already mentioned above is my idea of earlier GT ships for the USN, in the form of FT4-powered Knoxes/Brookes, though most probable is the Hamilton-class, which is already serving by 1967. GE picks up the challenge and offers a TF39 based design. With two competing naval GTs coming right up, there would be alot of prospect for small carriers, C14, and earlier DX/DXG. An earlier switch to GTs would also have a massive effect on older, steam ships like the Leahys and WW2 cruisers/FRAMcans. Eventual fossile fuel GT powered CSGs, CVLs and LHAs later on is a though-provoking prospect. Additionally, adopting Cru3 and old Cru's training regime could lead to a more successful USN air campaign over Vietnam, which could lead to more budget for the navy. Could we see accelerated SS(B)N and surface ship production in that scenario?
Click to expand...
Here are a couple of interesting numbers for you. Max surface warship production (by commissioning date) post war in the US was in 1961 with 14, which is also the tonnage max by a long shot. Three carriers, two Kitty Hawks and Enterprise, Long Beach, and 10 DDGs, four Farragut/Coontz and six Charles F. Adams. Max SS(B)N production was 1964 with seventeen boats commissioning, 13 SSBNs (3 Lafayette and 10 Madison) and four Permit/Thresher class SSNs. I don't think GTs have anything to do with reduced naval production since.

Incidentally, max amphibious ship production was 1970 with 14, one Blue Ridge LCC, one Iwo Jima LPH, three Austin LPDs, one Anchorage LSD, seven Newport class LSTs, and one Charleston class AKA. I haven't gone through to figure out what year was the max for auxiliaries yet since there are so many more types and classes to deal with.
 
asVAL said:
Some further pondering on my part
.....
  • Already mentioned above is my idea of earlier GT ships for the USN, in the form of FT4-powered Knoxes/Brookes, though most probable is the Hamilton-class, which is already serving by 1967. GE picks up the challenge and offers a TF39 based design. With two competing naval GTs coming right up, there would be alot of prospect for small carriers, C14, and earlier DX/DXG. An earlier switch to GTs would also have a massive effect on older, steam ships like the Leahys and WW2 cruisers/FRAMcans. Eventual fossile fuel GT powered CSGs, CVLs and LHAs later on is a though-provoking prospect. Additionally, adopting Cru3 and old Cru's training regime could lead to a more successful USN air campaign over Vietnam, which could lead to more budget for the navy. Could we see accelerated SS(B)N and surface ship production in that scenario?
Click to expand...
FT4A - yes, design work initiated in 1961*, in production by 1965** for the USCG's Hamilton class (14,000-18,000 shp)... and in an improved version by 1968 (22,000 shp) and 1970 (25,000 shp) (for merchant use.

The FT9 (40,000 shp) was available by 1988. It was developed from the civil JT9D (B747), which was developed from P&W's JTF14, its competitor to the TF39.


The LM2500 used all over the world now was developed in the last half of the 1960s to compete with the FT4A, it was operational and installed in its first hull by 1969 (full production was approved in 1972).
As the engine it was developed from, the TF39, was only first run in 1964, I can't see this being sped up much at all - the TF39 was still being debugged when the first LM2500s were installed, and they encountered similar problems requiring similar design fixes at the same time.
Later, higher-powered LM2500s were developed from the CF-6 (itself a civil improved TF39) in the 1990s.

The smaller LM1500 (based on the J79) WAS in operation from 1964 (13,000 shp) and had achieved 18,000 shp by 1973.




* at the request of the USN for its proposed hydrofoil patrol craft. The USN eventually chose LM2500s instead. {EDIT: The FT4A was based on the J75.}

** as well as a variant designated GG-4A in 1964 for Denmark's Peder Skram-class frigates (had the FT4A's gas generator and a Danish free-turbine section).

FT4A:


LM2500:
 
Last edited:
Somehow we went from Iroquois-powered fighters to USN Phantom alternatives before wandering off onto marine turbines. :rolleyes:
 
Cjc said:
I wonder if you could fit a Iroquois on a kfir.

​

Click to expand...

In theory, yes.

Published turbojet diameters are always tricky - what, exactly, was being measured? Some sources list the PS.13 Iroquois diameter as 39 inches (around 1.0 m) ... so closer to the Mirage's original Atar 9 than to the Kfir's J79. But other sources give the Iroquois diameter as 42 inches (1.10 m) or about the same as the J79.
 
Apophenia said:
In theory, yes.

Published turbojet diameters are always tricky - what, exactly, was being measured? Some sources list the PS.13 Iroquois diameter as 39 inches (around 1.0 m) ... so closer to the Mirage's original Atar 9 than to the Kfir's J79. But other sources give the Iroquois diameter as 42 inches (1.10 m) or about the same as the J79.
Click to expand...
The diameter of the Atar 9 was 36.2" for the main engine body and 40.2" for the afterburner module.

The J79 diameter was 30.4" - 31.6" for the main engine body (depending on model) and 38.3" - 39.1" for the afterburner module.

The J75 was 43" for the main engine body and 58.5" for the afterburner module.
 
I have serious doubts Canada could build, let alone sustain, a substantial number of Iroquois engines. And its producer would end of ended up to be absorbed by a larger company simply out of an inability to sustain a company on maintenance contracts.
 
MadRat said:
I have serious doubts Canada could build, let alone sustain, a substantial number of Iroquois engines. And its producer would end of ended up to be absorbed by a larger company simply out of an inability to sustain a company on maintenance contracts.
Click to expand...
the point of the idea was for some other nations being interested in the engine and maybe have the opportunity to start production of the engines under licence, the first nation that came to my mind initially was Italy with FIAT Aviazione having the competency of the production of the engine, at least locally, most likely under licence, it was just a thought exercise for alternative history, i can see France or even Israel trying to study the engine further so i wanted to see what people came up with
 
ItalianAFDFail said:
the point of the idea was for some other nations being interested in the engine and maybe have the opportunity to start production of the engines under licence, the first nation that came to my mind initially was Italy with FIAT Aviazione having the competency of the production of the engine, at least locally, most likely under licence, it was just a thought exercise for alternative history, i can see France or even Israel trying to study the engine further so i wanted to see what people came up with
Click to expand...

Exactly. FIAT Aviazione's long connections with Rolls-Royce suggest another interesting possibility for global Iroquois support.
 
personally i was looking into the feasability of the Iroquois in some of Italy's fighter projects i evaluated the attept of using the engine in a possible conventional version of the FIAT G-95, maybe /4 or /6 with a different wing layout reminiscent of the Lancer or other planes and i belive i can make it into a decent plane with this powerplant
 
But we are talking Italy who literally puckered their collective butts to afford a single 1,000 lb st thrust fighter bomber in the late 60s to early 70s. History was not kind to their economic position.

The UK and France had their own designs without the titanium issues. People forget that titanium was rare outside the CCCP.
 
MadRat said:
But we are talking Italy who literally puckered their collective butts to afford a single 1,000 lb st thrust fighter bomber in the late 60s to early 70s. History was not kind to their economic position.

The UK and France had their own designs without the titanium issues. People forget that titanium was rare outside the CCCP.
Click to expand...
sure thing, again it's just a thought and wanted to share, and of course it's always the "but it's italy" argument.
 
Scott Kenny said:
Yep. My favorite Cold War shenanigans story is how the CIA created enough shell companies to buy enough titanium from the USSR to build the Blackbirds.
Click to expand...

Remember the legend that the Soviets fired 4000 missiles at the SR-71 and never damaged it ? Well, they were kinda firing at their own titanium, flying above their heads. :p:p:p:p:D:D:D:D
 
MadRat said:
... The UK and France had their own designs without the titanium issues. People forget that titanium was rare outside the CCCP.
Click to expand...

Indeed they did. We know why Rolls-Royce lost interest in the Rb.106 but, with their own designs and all, why were the French interested in those titanium-crippled Iroquois?

Ti is more than rare - it doesn't exist as a metal in nature. But ilmenite is fairly common in Canadian Shield rocks. True, getting from crushed ilmenite to reducing rutile TiO2 to metallic Ti is very energy-intensive. But, remember, that ilmenite is mined in Québec or neighbouring Eastern Ontario - and Québec has a vast amounts of hydro-electric power.

Obviously, Orenda was confident that it could procure sufficient locally-refined Ti metal for Iroquois production. So, one OT question is: Why did the CIA go to all the trouble of buying Soviet titanium covertly? Was it to ensure cheap imports of Hydro-Québec power to the US grid via HQUS? Or were US allies like Canada, Australia, and New Zealand just not able to compete with bargain prices springing from the use of Soviet slave labour?
 
Apophenia said:
Indeed they did. We know why Rolls-Royce lost interest in the Rb.106 but, with their own designs and all, why were the French interested in those titanium-crippled Iroquois?
Click to expand...
Because to be blunt the French were behind in engine tech, with the Atar line being progressive iterations of the WW2-era BMW 003. It took two tech transfers from American engine makers to catch the French up in engine technology. They outright couldn't make something in the Iroquois thrust class without outside help.
 
CV12Hornet said:
I'd look at what the J75 was used for, and go from there. The Iroquois is in the same weight and thrust class as the J75, hence why the early Arrow prototypes used it. Other contemporary engines in this class were the advanced Olympus variants, the Gyron, and the RB.122.

Put another way, a single-engine Iroquois fighter would look a lot like the F-105, F-106, and Viggen.
Click to expand...
By way of comparison to give some idea of fighters that might be able to handle or more so to give an idea of where the Iroquois fits against other engines:

Engine
Orenda Iroquois​
P&W J75-P-17​
Snecma Atar 9C​
RR Avon Mk48A/RM6B​
GE J79-GE-3​
P&W J57-P-20​
Length
5.9 m​
6.035 m​
5.9 m​
3.23 m​
5.269 m​
6.197​
Diameter
110 cm​
112 cm​
100 cm​
107 cm​
97.3 cm​
99 cm​
Dry Weight
2110 kg​
2665 kg​
1456 kg​
1310 kg​
1508 kg​
2155 kg​
Thrust (Dry)
89 kN​
72 kN​
42 kN​
48.04 kN​
43.6 kN​
47.6 kN​
Thrust (Afterburning)
130 kN​
109 kN​
58.9 kN​
67.7 kN​
66.7 kN​
83.2 kN​
SFC
0.85/1.9​
?/2.15​
1.01/2.03​
0.93/1.85​
0.85/2.04​
0.77/2.1​
Sample Acft
??​
F-106​
Mirage III​
Saab J 35A/B/C Draken​
F-104A/B​
F-8E​
 
Apophenia said:
Indeed they did. We know why Rolls-Royce lost interest in the Rb.106 but, with their own designs and all, why were the French interested in those titanium-crippled Iroquois?

Ti is more than rare - it doesn't exist as a metal in nature. But ilmenite is fairly common in Canadian Shield rocks. True, getting from crushed ilmenite to reducing rutile TiO2 to metallic Ti is very energy-intensive. But, remember, that ilmenite is mined in Québec or neighbouring Eastern Ontario - and Québec has a vast amounts of hydro-electric power.

Obviously, Orenda was confident that it could procure sufficient locally-refined Ti metal for Iroquois production.
Click to expand...
Which honestly measures in at maybe 1000lbs per engine. Let's be generous and bump that to 1000kg per engine. I don't think the Iroquois was fully titanium, just a titanium hot section. Today, it'd be titanium last couple of compressor stages and turbines/housing.


Apophenia said:
So, one OT question is: Why did the CIA go to all the trouble of buying Soviet titanium covertly? Was it to ensure cheap imports of Hydro-Québec power to the US grid via HQUS? Or were US allies like Canada, Australia, and New Zealand just not able to compete with bargain prices springing from the use of Soviet slave labour?
Click to expand...
A blackbird needs on the order of 30-60 tonnes of Titanium per airframe, and that's assuming minimal machining losses. 30 tonnes is no machining losses at all, the bare airframe is 30 tonnes. And I've seen some items that have turned 15lbs of metal into 2.5lbs of finished product, so machining losses of up to 10:1 are not unreasonable. 300 tonnes of titanium per plane.
 
aim9xray said:
And wastage from QA failures (chlorine in the Burbank water supply). And 100% test coupons + traceability.
Click to expand...
I'm pretty sure the 300 tonnes per plane would include all that. Rolling bars into sheets is not particularly wasteful of materials, neither is forging.
 
Soviet titanium for Blackbird reconnaisance planes delays American build up of titanium industry for Blackbird (tactical) bombers. It is comforting in many ways that one fools the enemy; but be wary that the enemy might not be a fool.
 
One path out of the morass is to fund the Iroquois in scaled form to replace Avon, J57, and Atar sized engines.
Huge market there if you can get your foot in the door.

Canada is probably the one country that could achieve it too.
 
Scott Kenny said:
I'm pretty sure the 300 tonnes per plane would include all that. Rolling bars into sheets is not particularly wasteful of materials, neither is forging.
Click to expand...
How much of that 'wasteage' can be reclaimed and put back into the process?
 
zen said:
One path out of the morass is to fund the Iroquois in scaled form to replace Avon, J57, and Atar sized engines.
Huge market there if you can get your foot in the door.

Canada is probably the one country that could achieve it too.
Click to expand...

Yes. On Avon, Greg's table makes them look pretty close already. That's not really a surprise since RB.106 was meant to be a drop-in replacement for Avon ... and Orenda's owner, Avro Canada, was already very familiar with the RB.106.

If the Iroquois was to be scaled down, 97.3 cm diameter would seem to be the magic number (thus covering Avon, Atar, J57, and J79 options). If Rolls-Royce wasn't interested in co-development, Westinghouse in the US might have been.
 

Similar threads

Please donate to support the forum.

Back
Top Bottom