Avro CF-105 Arrow

[kitnut617]

You could always say that the centre bay is deeper at the expense of some fuel, but the left and right bays are shallower with different missiles in them. IIRC, the structure between the weapon pack and the "ceiling" of it's bay consists of a series of bolt-on cross-ways tie-rods, so they could be replaced with a "cranked" structure that cuts into the fuel tank space between the intakes.

Bear in mind that although the weapon bay doors in the pack are 16' long, the actual detachable pack is 2' longer due to the missile avionics crates at the front end. Relocate and/or miniaturise those electronics and you get an extra two feet of length to play with.

Just above the weapons bay are the two air intake ducts. It's the reason why the Sparrows had their fin tips protruding through small slots in the bay doors, they couldn't go any further upwards.  I made my weapons bay following the drawings posted below which are in the Arrowhead book. 

[kitnut617]

Hmmm ... I have some scans of it at home (so maybe just PM me) ... othewise I think at the Secret-Projects-Forum is a tread for it:

Correction: Here is it ...

http://www.avroarrow.org/AvroArrow/arrowtechdrawings2.html
http://www.avroarrow.org/interactive/weapac.asp
Deino

In one of the links here it says the weapons bay was bigger than a B-29's bay.  Here's a good example of mis-information.  You can actually stack about twenty Sparrows in just the forward bay of a B-29, the rear bay holding the same.  When I built my bay I tried to get four Sparrows in there, they will --- just.  But the problem is they can't be deployed, the higher ones just don't have the clearance when the mounting frames are extended.  Also with the mounting frame style, negates being able to lie the fins flat.  I also tried to place eight Falcons using the Falcons from an F-89 which are the earlier ones, they don't fit as shown in the drawing.  I haven't been able to make it work at all, I think the drawing has the missiles underscale to what they actually are.

[Deino]

Hi ... just found this !

http://www.arcforums.com/forums/air/index.php?showtopic=174564&st=0&gopid=1628561&#entry1628561


Deino

[Sauragnmon]

Well I think the vertical size of the R-27T that I hung in the bay is actually big enough to fit inside the bay's clearance itself, the only reason the pack is bigger, was simply for ease of construction on my part, and to accomodate the pylon that the missile is suspended on - in the real aircraft, it would likely be hung on a pair of swing arms to drop it out the bay.

I don't really need more lengthwise clearance in the bay, I'm just not sure if I can get the missiles into position with the doors closed - if I can get them in and closed inside 3" with the missiles sitting with their fins at standard 45 degree angle, it's all kosher - I'm rather sure I can get them in three widthwise, it's the height question that stands at my problem.  If not, I have to recess them into the bay, which I can also then claim other benefits for it, but I'm not 100% sure at this exact moment.  Cooling systems for the missiles would also be able to be placed if I had them semirecessed.  Just ran the numbers, the wingspan on the Phoenix is 3' wide, the lateral and vertical dimensions are then 2.121' and change, so there would be plenty of space in the pack to fit them fully internal.  Seats Four Phoenixes, if it's a little widened, with the 8' wide design.  I'm not sure if I'll have to, to fit the TF30's in place.  I'll deal with that when I get there.  I could always recess two and hang two as well.  Sit the outer pair recessed and the inner two internal, relying on the smaller diameter of the missile body itself at 15" to create space inside the bay.


Kitnut, as to your commentary on the bay on the model, it could also be Hobbycraft screwing with the actual dimensions - did you measure it out, the missiles as well, and test the numbers 100% to get it right?  

[kitnut617]

A quick comment to Deino's link to the ARC build.  he's doing a very nice job on that but I notice that he is building his weapons bay straight into the fuselage and not into the removable bay.

Sauragnmon--

I have a number of 1/72 Arrow kits, three (or four) of the Hobbycraft kit (second issue with the corrected wing orientation) and I also have a box full of the Victoria Productions vacuform kits.  That's because I own the moulds to this kit and it is renown for being one of the two really good kits of the Arrow (not me trying to sell it but what's written on the internet)  One of the first things I did was to compare the VP kit to the Hobbycraft kit and in most respects they are very close to being the same, the VP kit has way better 'engraved' detail though (once again, not me trying to sell the kit but ask JHM of his opinion of it as he has one now)  The weapons bay was one area I looked at closely because I'm toying with the idea of enhancing the VP kit with some resin and this is one area I'm looking at, so everything I find about the subject is of great interest to me.

I've read the thread on Secret Projects and for the most part it's written by people who 'think' they know all about it, there are some knowledgeable people there but for the most part I don't think so.  Almost all info is of speculation as most of the relevant info was destroyed when the project was cancelled and all people have to go by is the few items saved so finding true info is very difficult.  I've also read the threads on ARC and for now I'll keep my comments to myself.

Back to the weapons bay, on both kits they are about the same dimensions and they are about correct compared to the station drawing in the Arrowhead book, if you notice on mine the front and back have a sloping part, this is to avoid the structural stays that Weaver mentions and actually should be much shallower than how I've done mine, I did it this way because the missiles wouldn't fit in (BTW I shortened the Sparrows as the earlier version was a shorter missile),  I suspect, studying the drawings, that the top of the bay would have has slots in the roof just like the doors do.  There is mention somewhere that the designer goofed on the weapons bay design size.

[Weaver]

I've read the thread on Secret Projects and for the most part it's written by people who 'think' they know all about it, there are some knowledgeable people there but for the most part I don't think so.  Almost all info is of speculation as most of the relevant info was destroyed when the project was cancelled and all people have to go by is the few items saved so finding true info is very difficult.  I've also read the threads on ARC and for now I'll keep my comments to myself.

Well I originated the thread on Secret Projects and I certainly don't claim to know all about it, inded I started it to see if anyone knew better than me, and was rather surprised to get little response. Everything I've posted on there are back-of-a-fag-packet guesstimates but based on available evidence.

Regarding the 4 x Sparrow fit, there exists a photograph of a wind-tunnel model with four Sparrow-shapes underneath it on alternate short and long carriers, which implies that they're staggered in the stowed position. There are also the diagrams that Deino linked to, who's provenance I don't know. The information I could find suggested that Sparrow III was nearly a foot shorter than Sparrow II and had an inch and a half less span, which may be what made this arrangement possible with Sparrow III when it wasn't with Sparrow II.

Slots in the roof of the bay are interesting, since the shapes above them are the two oval section intake ducts and the oval section (as far as I can tell) fuel tank, which implies that there might be space for such slots between them, at least for the 3 x Sparrow fit.

Regarding my semi-serious suggestion that the centre station of the bay on Saur's model (i.e. the middle third) could be deeper at the expense of the fuel tank, I stand by this in principle. By the time they passed over the weapon bay, the intake ducts had morphed into tall ovals with a fuel tank between them, so the ducts would only have set a hard limit on the depth of the outer thirds of the pack, not the middle third. Now to make that middle third deeper, and the tank shallower, would involve replacing the bracing struts with some kind of arched structure which would probably be heavier, but it could, inprinciple, be done. Whether it would be wise is another matter entirely, however.....

[Weaver]

Saur: I made the box around a Sparrow's fins to be 2' 4" square, so your missiles should fit inside that. However, they wern't fully inside the bay on the Arrow, so it's hard to say: maybe yours could have exposed fins too?

[kitnut617]

My thoughts Weaver are that everything is very subjective.  The Arrow head book is probably as close as you will get with details, it is supposedly written on info provided through interviews with key people who were there at the time.  In Calgary there's an RC model shop which specializes in aircraft, the owner has a dedicated area sectioned of to all things Avro Canada.  He was also the guy who built the 1/8 scale flying model (powered by ducted fans BTW) which appeared in the TV mini-series starring Dan Ackroyd, this movie had supposedly technical help from the same key people, and the shop owner used the drawings in the book to build his model.  At the moment this guy, Dan Hyslop, and some other people have a project of building a real half scale flying Arrow using the same plans.  Here's a link to his shop:
http://www.actionhobby.ca/index.php

[jcf]

Some notes on the weapons pack, with examples and coming from decades of studying the drawings in the Arrowheads book (I have two copies, my original edition purchased in 1981 suffered a binding failure and was consequently taken apart and placed in my loose files, making it perfect for scanning  ).

1) the detachable weapons pack fits from Sta. 292 to Sta. 485, a space of 193 inches making the pack approximately 16 feet long.

2) the avionics visible in the weapons drawings posted by apophenia (from the Arrowheads book) are not part of the of the detachable pack,
they are in an avionics bay forward of the pack between Sta. 255 and Sta. 292. (note the lettering just visible in the upper left hand corner of the pack photo)

3) on page 27 of the book there is a reproduction of an Avro drawing of the pack showing four Sparrows, with doors (the drawing is white line on black, I've inverted the scan for clarity)

I measured the Falcon missiles in the Revell 1/72nd F-89 kit, using a 1/72nd scale rule, and they come out a scale foot too long, measuring 7.5' instead of  6.5'... they definitely would not fit, especially as the weapons bay on the 1/72 Hobbycraft Arrow is three feet short, as is the whole airframe going by the measurements on the Avro datum and 3-view GA drawings in the Arrowheads book. I don't have the 1/48th Arrow kits so I can't check them against the data.
BTW the Falcons in the Monogram/Revell 1/48th F-102A kit are within a hair of being bang-on an exactly scale 6.5' long.

Jon

[kitnut617]

Jon, that is very revealing, I just measured the bay from the Hobbycraft kit and it scales to 13 feet    So I went and got one of the VP kits and measured that, well it measures out at 15 feet.

[Jeffry Fontaine]

Has anyone been following Pete Malaguti (K2Pete) and his attempt to build the HobbyCraft CF-105?  Not just one CF-105 mind you but two of them. 
He certainly has done wonders with those kits.  Here are the links:

HobbyCraft (original mold) CF-105 WIP by Pete Malaguti (K2Pete)
Darn nice job on opening up the weapons bay and incorporating some Sparrow missiles on launch rails with this kit. 

HobbyCraft (new mold) CF-105 WIP by Pete Malaguti (K2Pete)
He is really going out of his way on this project with the addition of the RADAR, weapons pallet, and an Iroquois engine on a maintenance dolly. 

[Sauragnmon]

I saw his extra-detailed build the other day, interesting thread that.  Quite nicely detailed stuff.

I would surmise the 16' long weapons bay would be theoretically able to support a small set of AIM-54's at that point, with some widening of the fuselage to accomodate AWG-9 radar in the nose.  Random thought.

If the arrow pack is 3' short on the Hobbycraft kit, as is the rest of the fuselage, I would be tempted, when I build my Super Arrow, to build in a plug in the bay area to fit this new adjusted length.  Again, a random thought.

[Captain Canada]

Those are both simply awesome.

[Hman]

http://www.juniorgeneral.org/donated/2009/aug14/arrow.png


Instant Arrows !

[Jeffry Fontaine]

Has anyone been following Pete Malaguti (K2Pete) and his attempt to build the HobbyCraft CF-105?  Not just one CF-105 mind you but two of them. 
He certainly has done wonders with those kits.  Here are the links:

HobbyCraft (original mold) CF-105 WIP by Pete Malaguti (K2Pete)
Darn nice job on opening up the weapons bay and incorporating some Sparrow missiles on launch rails with this kit. 

HobbyCraft (new mold) CF-105 WIP by Pete Malaguti (K2Pete)
He is really going out of his way on this project with the addition of the RADAR, weapons pallet, and an Iroquois engine on a maintenance dolly.

Looks like Pete Malaguti (K2Pete) has finished his CF-105 Arrow project as it is now a front page article on ARC