Avro CF-105 Arrow and its variants

[fortrena]

From the looks of it, the RCAF initially planned to acquire 500 to 600 CF-105s. These aircraft were to be delivered both to regular and reserve squadrons, twenty or so units in all. For a variety of reasons (rising costs, complexity of the aircraft, etc.), the number of aircraft dropped to 100 to 150, which were to be delivered to regular units only. The unit cost of the Arrow went through the proverbial roof as a result of that reduction in the number of aircraft on order.

 

[riggerrob]

From the looks of it, the RCAF initially planned to acquire 500 to 600 CF-105s. These aircraft were to be delivered both to regular and reserve squadrons, twenty or so units in all. For a variety of reasons (rising costs, complexity of the aircraft, etc.), the number of aircraft dropped to 100 to 150, which were to be delivered to regular units only. The unit cost of the Arrow went through the proverbial roof as a result of that reduction in the number of aircraft on order.

Yes.
Also consider that senior RCAF staff officers had unrealistic opinions about how many airplanes the Treasury was willing to finance.

 

[Darthtabby]

Fact was that Arrow combat range was short, very short... 200 to 300 miles... no more. A bit surprising for an aircraft this size, yet the Iroquois and delta wing drag may explain part of it (even with primitive analog FBW, surface of that wing was colossal: 114 m2). For the sake of comparison a Mirage IVA was barely 75 m2, and so was the Mirage 4000.

Some documents about the Arrow use the word range when they should use radius. Performance of the Arrow 2: periodic performance report no. 15 published in November 1958 estimated a combat radius from 338nmi to 589nmi depending on profile (the 338nmi was for a Mach 1.8 mission while the 589nmi figure was for a completely subsonic mission). It also included estimates of of what each 1000lbs of extra fuel or weight reduction would affect each profile (the report stated that the Operational Empty Weight used was "conservative and approximate only" though it did assume 2180lbs of fuel in the weapons pack in addition to 19,433lbs).

A post cancellation document published in 1961 titled A Limited Technical Evaluation of the Avro Arrow Interceptor System includes details about the mission profiles used for the estimates such as cruise speed and length of combat though it is one of the documents that says range where it should say radius (it uses the estimated figures from the 1958 Performance Report but lists them as range instead of radius).

 

[Yellow Palace]

Some documents about the Arrow use the word range when they should use radius. Performance of the Arrow 2: periodic performance report no. 15 published in November 1958 estimated a combat radius from 338nmi to 589nmi depending on profile (the 338nmi was for a Mach 1.8 mission while the 589nmi figure was for a completely subsonic mission).

By way of comparison, the F-106A had a combat radius of 477 nautical miles for a completely subsonic mission under comparable (maximum internal fuel) conditions.

 

[Archibald]

Please reassure me, "combat range" is twice "combat radius" ? or not at all ? plus nautical miles, as if imperial units weren't annoying enough...

 

[Darthtabby]

Please reassure me, "combat range" is twice "combat radius" ? or not at all ? plus nautical miles, as if imperial units weren't annoying enough...

Range is how far an aircraft can fly, radius is how far it can fly and then return to its starting point. Both can vary considerably depending on assumptions made such as mission altitude and how much is put aside for combat maneuvering and emergency reserves. Range isn't necessarily twice radius: from what I've been told that for WWII carrier planes radius was about a third of range, I suspect in large part because of the practice of massing large groups of aircraft.

Edit: Looking at how many posts you have I wonder if I might have misinterpreted your question.

A mile is 1.609 kilometers and a nautical mile is 1.852 kilometers.

Some documents about the Arrow use the word range when they should use radius. Performance of the Arrow 2: periodic performance report no. 15 published in November 1958 estimated a combat radius from 338nmi to 589nmi depending on profile (the 338nmi was for a Mach 1.8 mission while the 589nmi figure was for a completely subsonic mission).

By way of comparison, the F-106A had a combat radius of 477 nautical miles for a completely subsonic mission under comparable (maximum internal fuel) conditions.

The F-106 could extend its range considerably with a pair of underwing tanks though. Not sure how much of a radius boost one could expect from the Arrow with an external tank. The external tank the Arrow was supposed to be able to carry was fairly large (500 Imperial gallons; note that imperial Gallons are slightly larger then US gallons) but it was only designed to carry one and it had two engines to feed from it versus one on the F-106.

Today I discovered a document titled RCAF engineering study request on Arrow 2: increased combat radius. It projected that an extended range version of the Arrow with an additional 9300lbs of internal fuel would have a 40-90% increase in radius over the basic Arrow 2 depending on the mission profile being flown. Though in order for a radius of 439nmi for the supersonic (Mach 1.5) mission and 639nmi for an internal fuel subsonic mission (with mach 1.5 combat) to be 90% and 80% higher then the basic aircraft the base aircraft's radii with those mission profiles would have to be 231nmi and 355nmi: both much lower then estimates for similar missions (358nmi and 509nmi) in the periodic performance report I linked to in a previous post. The periodic performance report was published a few months later and added 2180lbs of fuel in the weapons bay but that doesn't seem like enough to boost the basic airframe (without the extra 9300lbs) radius that much.

 

[royabulgaf]

Fact was that Arrow combat range was short, very short... 200 to 300 miles... no more. A bit surprising for an aircraft this size, yet the Iroquois and delta wing drag may explain part of it (even with primitive analog FBW, surface of that wing was colossal: 114 m2). For the sake of comparison a Mirage IVA was barely 75 m2, and so was the Mirage 4000.

Some documents about the Arrow use the word range when they should use radius. Performance of the Arrow 2: periodic performance report no. 15 published in November 1958 estimated a combat radius from 338nmi to 589nmi depending on profile (the 338nmi was for a Mach 1.8 mission while the 589nmi figure was for a completely subsonic mission). It also included estimates of of what each 1000lbs of extra fuel or weight reduction would affect each profile (the report stated that the Operational Empty Weight used was "conservative and approximate only" though it did assume 2180lbs of fuel in the weapons pack in addition to 19,433lbs).

A post cancellation document published in 1961 titled A Limited Technical Evaluation of the Avro Arrow Interceptor System includes details about the mission profiles used for the estimates such as cruise speed and length of combat though it is one of the documents that says range where it should say radius (it uses the estimated figures from the 1958 Performance Report but lists them as range instead of radius).

Sounds to me like they were using the most optimistic estimates they could get away with .

 

[Scott Kenny]

Please reassure me, "combat range" is twice "combat radius" ? or not at all ? plus nautical miles, as if imperial units weren't annoying enough...

Radius can include a period of maneuver, so isn't necessarily simply half the combat range.

And Nautical Miles are simple: 1 minute of latitude, 1/60th of a degree. Very convenient for navigation. And also now defined as 1852m.

 

[NMaude]

And also now defined as 1852m.

Or 6076 Ft.

 

[JFC Fuller]

Reconnaissance version of the Mk.3, with wingtip ramjets and canards, in the attached images. The design target was Mach 2.5 at 90,000ft with a reconnaissance pack. These are from the report here, that I have also uploaded in case the link dies.

 

[riggerrob]

Pilots and air traffic controllers prefer nautical miles for time-and-distance calculations. They just abbreviate nautical miles to “6000 feet” and it becomes much easier to do mental math related to 60 seconds. Also consider how many different ways you can divide 6,000 mentally: 1, 2, 3, 4, 5, 6, 10, 15, 20, 25, 30, 40, 50, 60, etc.

 

[iverson]

Reconnaissance version of the Mk.3 with wingtip ramjets and canards in the attached images. The design target was Mach 2.5 at 90,000ft with a reconnaissance pack. These are from the report here, that I have also uploaded in case the link dies.

Sounds to me like they were using the most optimistic estimates they could get away with .

The whole thing looks a bit Rube Goldberg. Was there a serious requirement for such an aircraft or was this proposal just another attempt at justifying the sunken costs of the Arrow program?

 

[Yellow Palace]

The F-106 could extend its range considerably with a pair of underwing tanks though.

705 nautical miles radius for the all-subsonic mission with two 220 US gallon tanks, just shy of a 50% increase in radius. The CF-105 seems (as per Engineering Study SS.119 you've cited) to have been planned for a single 500 gallon tank, which is about the same amount of fuel as two 220 US gallon tanks. Almost certainly less overall improvement there.

Today I discovered a document titled RCAF engineering study request on Arrow 2: increased combat radius. It projected that an extended range version of the Arrow with an additional 9300lbs of internal fuel would have a 40-90% increase in radius over the basic Arrow 2 depending on the mission profile being flown. Though in order for a radius of 439nmi for the supersonic (Mach 1.5) mission and 639nmi for an internal fuel subsonic mission (with mach 1.5 combat) to be 90% and 80% higher then the basic aircraft the base aircraft's radii with those mission profiles would have to be 231nmi and 355nmi: both much lower then estimates for similar missions (358nmi and 509nmi) in the periodic performance report I linked to in a previous post. The periodic performance report was published a few months later and added 2180lbs of fuel in the weapons bay but that doesn't seem like enough to boost the basic airframe (without the extra 9300lbs) radius that much.

The figures in Periodic Performance Report 15 take into account revised drag and engine performance data since Periodic Performance Report 14, for which no date is given. Given the time elapsed between the two reports, it's likely that SS.119 uses the earlier data. The mission profiles do appear to be identical for the two reports.

Performance Report 15 gives figures for range improvement for additional internal fuel; it's certainly optimistic to assume that this improvement is linear for such a large increase in fuel, but that can define an upper bound. SS.119 also doesn't appear to include the effect of a weapons bay tank, so the two are cumulative (i.e. 11,480 lbs fuel above the design baseline).

The operating empty weight is also reduced by 461 pounds in Performance Report 15, which further improves radius, though only by 5-10 miles - though some of that is going to be swallowed back up by the alterations to accomodate the extra fuel, so I've not taken it into account.

Combining the two, we get an upper bound of:

• 831 nautical miles radius for subsonic cruise/supersonic combat
• 603 nautical miles radius for Mach 1.5 cruise & combat

Real performance would, presumably, lie between these and the corresponding fucures in SS.119.

 

[JFC Fuller]

This document gives performance figures for the Mk.2A (image also attached), that would have resulted from the implementation of the range increase measures described in SS119, linked to by @Darthtabby , it references back to other official documents. It also gives performance figures for the Mk.3 and seems to confirm that the ultimate Mk.3 would have been the Mk.2A with the uprated Orenda Iroquois 3 engines fed through variable geometry intakes with additional insulation applied to the aircraft to withstand the greater heat associated with Mach 2.5-3 speeds. The reliance of the Mk.3 proposal on insulation is confirmed by this letter from A.V. Roe engineer William Kusyk dated August 28th 1958, image also attached.

The RAF considered the CF-105 Mk.2 as an interim aircraft to it's OR.329 interceptor, the CF-105 Mk.3 had intended performance in the range required of O.329. A fun alternative history could be the RCAF and RAF jointly developing the CF-105 for their interceptor needs and jointly developing the Hawker P.1121, with the Iroquois engine, to replace the Canadir Sabres in the Canadian Air Division in Europe and the Venom FB.4s the RAF ultimately replaced with the Hunter FGA.9/FR.10 (in turn, later, intended to be replaced by the P1154). The Iroquois was a candidate for the P.1121, the below is from a talk to the Hawker Association, covering the life of Charles Plantin by his son-in-law, David Hassard, emphasis mine:

The same year, with Frank Cross, the Chief Experimental Draughtsman, he crossed the Atlantic by BOAC Stratocruiser to visit Avro Canada, Orenda Engines and the US Bendix Corporation to study North American design and production methods and to assess the ill-fated supersonic CF105 Arrow all-weather fighter with its 25,000 lb static thrust Iroquois reheated turbojet, the latter being a contender for Hawker’s equally ill-fated P.1121, both eventually being cancelled. Charles and Frank concluded that Hawker needed to double the size of its design and R&D organisations to keep up in fighter development.

 

[Archibald]

The RAF considered the CF-105 Mk.2 as an interim aircraft to it's OR.329 interceptor, the CF-105 Mk.3 had intended performance in the range required of O.329. A fun alternative history could be the RCAF and RAF jointly developing the CF-105 for their interceptor needs and jointly developing the Hawker P.1121, with the Iroquois engine, to replace the Canadir Sabres in the Canadian Air Division in Europe and the Venom FB.4s the RAF ultimately replaced with the Hunter FGA.9/FR.10 (in turn, later, intended to be replaced by the P1154).

Amen to that, bro !

Oh crap, that would be totally awesome. In a sense, it would be like UK passing the aerospace torch to Canada. Not sure if british aircraft industry (or what was left of it after Sandys) would appreciate.

Tony Buttler mentions that the interim fighter before F.155T IOC in '62 was, first, the Thin Wing Javelin (which ended as an enormous monster with Olympus engines) and then the CF.105 buried it performance wise. Still, the 1957 Arrow seemingly was not good enough for F.155T, not even as an interim type. As you note, Mk.3 may change that opinion.

 

[NMaude]

The UK blew a big opportunity in dropping the P.1121.

 

[hesham]

From Air Pictorial 1965.

 

[NMaude]

I always use 7-Zip for that: https://www.7-zip.org/

I use a MacIntosh, are there any equivalents for a Mac?

 

[Hobbes]

Stuffit Expander can open 7zip files.
The .zip format can be opened by the built-in Archive utility on the Mac.

 

[Photon440]

I hope that one day someone will using the Arrow-1 blueprints to build a flying full-scale replica of RL-201 (There should still J-75 turbojets lying around too).

There is the 2/3 flying replica project currently under construction: https://www.avromuseum.com/arrow-ii-project.html

 

[hesham]

From, Avro Aircraft and Cold War Aviation