Author Topic: Avro CF-100 Variants  (Read 684 times)

Offline kitnut617

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Avro CF-100 Variants
« on: July 18, 2018, 11:31:47 PM »
This is a subject I had started to build. I'd built a Mk.4B and thought I would make the other variants. I was lucky when someone on The Airfix Tribute Forum was selling another Mk.4 and a Mk.5 because I was having trouble finding them on the internet.

First off I started to convert the Mk.4 back into a Mk.3, and I found CanMilAir does a couple of sheets for the Mk.3. I found a side view drawing of the different variants, and scaled the drawing to match the Mk.4 kit. To my amazement after I did that, I found all the panel lines matched. Now whether the drawing is highly accurate is not what I'm worried about, I'm just converting the Mk.4 back into the Mk.3 using it. Next was to find out what the Mk.3 wing tips looked like (because they originally didn't have the wing tanks)

Top pic shows the drawing I found on the internet. Second pic is of a drawing I found which shows the Mk.3 wing tips
« Last Edit: July 19, 2018, 04:06:41 AM by kitnut617 »

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #1 on: July 18, 2018, 11:36:14 PM »
The Mk.3 is progressing quite well, there's a lot of cutting and shortening, but not everything is shortened the same amount, the fuselage has to shortened the most, but the engine nacelles not nearly the same amount. Then the intakes have to be reprofiled.

In this pic you can see the difference between the Mk.3 engine pod and the Mk.4 one. The fuselage gets reduced in length by the amount of the RP bay which is behind the gun bay. But you still have to move the canopy running rail differently to what is moved on the lower side.
« Last Edit: July 19, 2018, 04:07:26 AM by kitnut617 »

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #2 on: July 18, 2018, 11:51:47 PM »
I started the Mk.5 build at the same time with the plan to build OOB. The plan quickly collapsed ----

While I was building my Twin Fury I was looking for P-51H type wings and as I was building the CF-100 Mk.3 around the same time I notice the outline of the Mk.3 wing looked very familiar. It has the same outline as the P-51H, actually it's more a scaled up F-82 outer wing.

So while laying the P-51H and F-82 wings over the Mk.4 wing, one of them sort of ended up near the wing tip ---- and then I thought "whoa!" that would work for an extended wing. I had an abandoned Beechnut P-51H in the spares box (it's undersized for 1/72, more like 1/75) so after thinning the wings from it to get it down to the CF-100 thickness, I found that the outline kept getting smaller as I thinned the chord thickness. Which worked out for what I wanted to do, because it meant I could move the P-51H wing further out towards the wing tip, making the wing even more extended.

The next part was what to use for a recce nose, and couldn't find what I thought I had in the spares box. But there sitting on my work bench shelf was this recce pannier from a TSR2 conversion. Then an idea started to seed itself into my mind.

To get the pannier to fit under the fuselage meant I had to move the main gear bays further out, which would be very difficult to do because the undercarriage doesn't fit in the wing, they are all under the engine pods and fuselage. So I thought I would just move the engine pods further out, but then had another thought, I'll re-engine it with high bypass turbofans at the same time.

The Mk.5 is a good choice to do an high altitude recce bird, the tail plane is quite a bit wider than the tail planes on the other versions.

Then after I had made my fuselage changes --- I found the recce nose I knew I had. It's from an RF-101C which I've converted back into an F-101A. So I thought 'what the heck! I'll stick that on too'  >:D

So these pics show where I'm at with this one.
« Last Edit: July 19, 2018, 12:08:06 AM by kitnut617 »

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #3 on: July 18, 2018, 11:52:44 PM »
This is a pic of the three together

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #4 on: July 19, 2018, 12:15:47 AM »
I'm not going to put wing tip tanks on the recce bird, I'll put them on pylons which are closer to the fuselage. Like this Mk.5D below. Only I'll have two pylons under each wing. I've found some photos of the CF-100 that was trialed for ground attack, it had four pylons for carrying bombs. The drop tanks will go on the inner pylons, and the outer ones will carry jamming pods like in the photo here. You can see the type I'm going to use in the bottom pic in reply #3
« Last Edit: July 19, 2018, 12:22:14 AM by kitnut617 »

Offline tankmodeler

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Re: Avro CF-100 Variants
« Reply #5 on: July 19, 2018, 01:57:24 AM »
I've found some photos of the CF-100 that was trialed for ground attack,
I like the idea of a more dedicated ground attack CF-100.
Stronger wings with the capability of taking TERs with 3x 1000 lb Mk 83 Snakeye bombs or, late in life, a laser designator pod on one pylon and GBUs  on the outer pylons.

Replace the outdated MX radar and guidance system with a smaller target radar, an IRST ball and maybe, later a LLTV or laser designator under the nose. Replace the MGs in the under-fuselage pod with a semi-recessed M-61 Vulcan or a couple of 20mm or 30mm cannon.

Retain the tip tanks or substitute them for Sidewinders for self defence.

That's not a horrible medium strike aircraft for the later 50s through mid 70s period.

Quote
and the outer ones will carry jamming pods like in the photo here.
Technically, these aren't "jamming" pods. they are chaff pods that dispense packets of precut chaff to blind intercept radars.

A jamming pod would have at least a couple of dielectric panels for the radiating and receiving antennas and, if not using airframe power (if it was a powerful pod) probably a small turbine in front to provide power through a RAM generator.

For photo recce, a chaff pod is a perfectly good fit, though.

Actually, this gives me the alternate idea of a Clunk Wild Weasel with a couple of high powered jamming and receiving pods and a couple of Shrikes/HARMs under the wings. That'd be kinda cool.

Paul

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #6 on: July 19, 2018, 02:18:53 AM »
For some reason, the trials for the ground attack showed that the CF-100 wasn't up to it.

The pylons though look like early AD-1 pylons
« Last Edit: July 19, 2018, 02:21:44 AM by kitnut617 »

Offline pigflyer

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Re: Avro CF-100 Variants
« Reply #7 on: July 19, 2018, 03:24:23 AM »
Cool looking work. And of course as a what if, you can't get it wrong.  Great idea.
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Offline The Big Gimper

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Re: Avro CF-100 Variants
« Reply #8 on: July 19, 2018, 03:47:38 AM »
These are awesome Robert. At some I will provide an update on my Mk.6 build.
Work in progress ::

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Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #9 on: July 19, 2018, 04:13:35 AM »
Cheers guys ---

The nose on the Mk.3 comes from an F-15  -----   slightly re-profiled   ;)

Offline tankmodeler

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Re: Avro CF-100 Variants
« Reply #10 on: July 25, 2018, 05:27:02 AM »
For some reason, the trials for the ground attack showed that the CF-100 wasn't up to it.
The wing structure was never rated for high loads or for a lot of aerobatics. It really was supposed to fly an intercept course for a slow bomber and blast it with guns or rockets. No real manoeuverability or high G loading required.

Strike fighter bombing usually involved a level of diving and pulling out that the CF-100 was never designed for.

Paul

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #11 on: July 25, 2018, 07:22:55 AM »
For some reason, the trials for the ground attack showed that the CF-100 wasn't up to it.
The wing structure was never rated for high loads or for a lot of aerobatics. It really was supposed to fly an intercept course for a slow bomber and blast it with guns or rockets. No real manoeuverability or high G loading required.

Strike fighter bombing usually involved a level of diving and pulling out that the CF-100 was never designed for.

Paul

I think they should've given it another try when they built the Mk.5. That's because the wing was strengthened. The Hobbycraft kits actually have different wing structures/panel lines between their Mk.4 and the Mk.5 kits

Offline tankmodeler

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Re: Avro CF-100 Variants
« Reply #12 on: July 31, 2018, 04:28:10 AM »
I think they should've given it another try when they built the Mk.5. That's because the wing was strengthened. The Hobbycraft kits actually have different wing structures/panel lines between their Mk.4 and the Mk.5 kits
Yeah, it was strengthened, but still not to the point where the repeated load cycles and low level aerobatics would not have caused serious fatigue issues early in its career.

Not to say that they could not have done so, but there was no need seen. The CF-100 was a dedicated subsonic interceptor and was supposed to be anything else. Modifications during production were to enhance its interceptor role, not change roles. This was the cold war. Wars of the future were going to short and nuclear, ground attack/CAS/conventional strike was not something that was envisioned on the "Nuclear Battlefield of the Future (tm)".

10 years later Vietnam and the various Arab Israeli wars showed that low level hell was still a relevant proposition, but by then the CF-100 was outdated and Canadian budgets were being slashed.

Still, a strengthened CF-100 with afterburning Orendas, or non-afterburning JT-3s (J52), some armour plate and an M-61 in the weapons bay, could have been very potent as it's low level handling was considered excellent and the straight wing would have provided ample space for weapons pylons and additional fuel tankage to extend loiter. The second crewman could be deleted from a straight up attack version with further increases in fuel tankage.

Coulda been a contenda'!

Paul

Offline elmayerle

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Re: Avro CF-100 Variants
« Reply #13 on: July 31, 2018, 09:25:09 AM »
Well, for night/bad weather operations, I could see the second crewman being very useful, particularly if suitable sensor fit was made.

Offline Brian da Basher

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Re: Avro CF-100 Variants
« Reply #14 on: August 01, 2018, 01:00:53 AM »
This is some fascinating stuff and you've got some very well-thought out ideas, Robert!

Will watch with interest as I've got a swept-wing Clunk planned inspired by the CF-103.

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Offline tankmodeler

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Re: Avro CF-100 Variants
« Reply #15 on: August 02, 2018, 09:11:51 AM »
Well, for night/bad weather operations, I could see the second crewman being very useful, particularly if suitable sensor fit was made.
The CF-100 was a dedicated night/all weather interceptor. The second crewman operated the state of the art collision course intercept system and radar.

In the twilight of its career the last operational Clunks were flown by 414 Sqdn who were an Electronic warfare squadron which, in peacetime, were tasked with simulating enemy attacks on North America to exercise NORAD while pretending to be Bears and Blinders. A lot of US and Canadian cities were "bombed" by these aircraft when they managed to elude or spoof the defending NORAD fighters.

Online finsrin

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Re: Avro CF-100 Variants
« Reply #16 on: August 03, 2018, 04:10:07 PM »
Extended wing recon version is nifty.

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #17 on: August 04, 2018, 11:04:45 PM »
Thanks Bill ---

The nice thing about using the Mk.5 wing is that the bottom part (yes it has two parts even though the wing is ultra thin) has an extension for the four foot wing extension moulded in. I'm going to use it to support my even longer extension top part and then cut a slot into the bottom half of my extension to suit it. My extension adds another seven feet to the wing tips of each wing, that's over and above the four feet the Mk.5 had..
« Last Edit: August 04, 2018, 11:06:24 PM by kitnut617 »

Offline tankmodeler

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Re: Avro CF-100 Variants
« Reply #18 on: August 14, 2018, 01:12:33 AM »
With the fan nacelle modifications it certainly looks like a Canadian RB-57 Canberra/Clunk cross, doesn't it?

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #19 on: August 14, 2018, 07:56:31 AM »
With the fan nacelle modifications it certainly looks like a Canadian RB-57 Canberra/Clunk cross, doesn't it?

Well I have an RB-57F build ongoing ---- It did give me the idea for this one, especially after I had moved the engine nacelles outwards so I could fit the recon pannier between the u/c bays. Just seemed a natural progression --- 

Offline tankmodeler

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Re: Avro CF-100 Variants
« Reply #20 on: August 14, 2018, 11:32:56 PM »
Just seemed a natural progression ---
Yep, certainly does.

Producing a TF-33 -like turbofan version of the Canuck's Orenda engine could easily have seen the thrust increase from the 7400 lbf of the Orenda-9, dry, to something like 11,000 lbf, dry, an exceptionally healthy increase, along with an increase in range as well.

Perfect for a recce version, as you show, and also useful if the wings were strengthened and the aircraft turned into a single-seater bomb truck. Actually, if the second seat was retained and precision bombing aids added, it could have been a precision strike aircraft along the lines of the A-6 or Buccaneer. That would have been cool to see in Europe in the early 60s in the grey/green camo pattern, no?

I think I've got a Clunk in the stash somewhere...

Paul

Offline elmayerle

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Re: Avro CF-100 Variants
« Reply #21 on: August 17, 2018, 12:41:43 PM »
How easy the Orenda could be converted to a turbofan is another question.  If it's a single-spool engine, it's going to be difficult without adding another spool (much like what GE did in converting the CJ610 to the CF700).  If it was a twin-spool engine, the conversion is much simpler, involving a redesign of the first few compressor stages to fans (JT3C --> JT3D, JT8B (J52) --> JT8D, etc.).  Not trying to throw cold water on the idea, just pointing a few things out.  Perhaps use an intermediate stage between Orenda and Iroquois that fits the Orenda envelope, but is twin-spool, as a basis for the turbofan; it could've been a proof-of-concept effort that went into production.

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #22 on: August 17, 2018, 08:21:00 PM »
For my project the idea is in typical Canadian Government fashion, something was 'picked-off-the-shelf'   :P  Of course it took years to develop    ;D ;D ;D

Offline tankmodeler

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Re: Avro CF-100 Variants
« Reply #23 on: August 18, 2018, 01:29:06 AM »
How easy the Orenda could be converted to a turbofan is another question.  If it's a single-spool engine
It was, indeed, a single spool engine. And, yes, it's really not possible to convert it to a turbofan without adding a second spool, the mass flow and speed requirements pretty much demand a second spool.

As a WHIF, we can imagine that after the Orenda 11 a new engine was created that used many Orenda parts and stages, but was designed around 2 spools and was a forward-mounted, low bypass turbofan.

In a more real-life game of what if, one could take an Orenda engine and do what GE did for the J-79, add a separate fan and turbine stage at the back of the engine, "simply" lengthening the whole thing by the added turbine stages and fan stage. This does work and was in service on the Convair 990 with CJ805-23 engines.

For the model it would reverse the short fan cowl, putting it at the aft end of the engine.

Paul

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Re: Avro CF-100 Variants
« Reply #24 on: August 18, 2018, 07:18:02 AM »
What about shifting to the two-spool Orenda PS.13 Iroquois for the basis for your turbofan derivative? Diameters for the Iroquois and Orenda 14 are the same - 42 inches.
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Offline elmayerle

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Re: Avro CF-100 Variants
« Reply #25 on: August 18, 2018, 11:26:26 AM »
How easy the Orenda could be converted to a turbofan is another question.  If it's a single-spool engine
It was, indeed, a single spool engine. And, yes, it's really not possible to convert it to a turbofan without adding a second spool, the mass flow and speed requirements pretty much demand a second spool.

As a WHIF, we can imagine that after the Orenda 11 a new engine was created that used many Orenda parts and stages, but was designed around 2 spools and was a forward-mounted, low bypass turbofan.

In a more real-life game of what if, one could take an Orenda engine and do what GE did for the J-79, add a separate fan and turbine stage at the back of the engine, "simply" lengthening the whole thing by the added turbine stages and fan stage. This does work and was in service on the Convair 990 with CJ805-23 engines.

For the model it would reverse the short fan cowl, putting it at the aft end of the engine.

Paul
That could be done, but I admit to still being partial to my idea of an intermediate stage between Orenda and Iroquois that initially served as a two-spool testbed and was later put into production for "special" CF-100 variants and other special projects.  Basically the Orenda 11 that tankmodeler described.  I could see a later variant of the high-altitude CF-100 getting powered by a dry turbofan version of the Iroquois (after all, P&W did scheme, and did component testing on, a JT4D turbofan version of the J75; just never got any sales so didn't build any).

Offline kitnut617

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Re: Avro CF-100 Variants
« Reply #26 on: Today at 06:51:05 AM »
How easy the Orenda could be converted to a turbofan is another question.  If it's a single-spool engine
It was, indeed, a single spool engine. And, yes, it's really not possible to convert it to a turbofan without adding a second spool, the mass flow and speed requirements pretty much demand a second spool.

As a WHIF, we can imagine that after the Orenda 11 a new engine was created that used many Orenda parts and stages, but was designed around 2 spools and was a forward-mounted, low bypass turbofan.

In a more real-life game of what if, one could take an Orenda engine and do what GE did for the J-79, add a separate fan and turbine stage at the back of the engine, "simply" lengthening the whole thing by the added turbine stages and fan stage. This does work and was in service on the Convair 990 with CJ805-23 engines.

For the model it would reverse the short fan cowl, putting it at the aft end of the engine.

Paul
That could be done, but I admit to still being partial to my idea of an intermediate stage between Orenda and Iroquois that initially served as a two-spool testbed and was later put into production for "special" CF-100 variants and other special projects.  Basically the Orenda 11 that tankmodeler described.  I could see a later variant of the high-altitude CF-100 getting powered by a dry turbofan version of the Iroquois (after all, P&W did scheme, and did component testing on, a JT4D turbofan version of the J75; just never got any sales so didn't build any).

Interesting twist to the thread this, because for my Avro Atlantic which in my alt-history world, was built by Avro Canada for Avro GB and also supplied it to the RCAF as the CC-137 Husky instead of the Boeing 707. My story has it powered by four Iroquois without afterburners.  This could fit in here.
« Last Edit: Today at 07:06:13 AM by kitnut617 »