CAC CA-15 original design

Antonio

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http://en.wikipedia.org/wiki/CAC_CA-15

I have discovered that CAC CA-15 initial design was different from the aircraft flown in 1946. At the begining, the selected powerplant was the radial R-2800.

Can anybody post a drawing of that configuration?

Thanks in advance :)
 
I've found only that pic:

http://www.netwings.org/library/CFS2_Planes/Other/
 

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...Think I have to purchase a copy of Unknown Number 15:

http://www.luft46.com/rd/rdreams.html

Evolution of Australian WWII fighters
 
Interesting, I think, is the shape of the fuselage underside, which shows an
distinctive kink, probably as an outlet for cooling air. I cannot remember seeing
such an installation in another R-2800 powered aircraft.
 

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It doesn't appear that the exhaust exits at the rear of the cowl, it just looks too tight, so possibly this shape not only helps with cooling, but also is where the exhaust exits. Maybe like an abbreviated version of the P-47's exhaust system.



Jemiba said:
Interesting, I think, is the shape of the fuselage underside, which shows an
distinctive kink, probably as an outlet for cooling air. I cannot remember seeing
such an installation in another R-2800 powered aircraft.
 
Comparison drawing showing R-2800 and Griffon engine designs.

Picture of mockup with R-2800 engine.

I'm afraid I can't remember the source.
 

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From
-NKR Models
-APMA 3-1995
-"The Wirraway, Boomerang &CA-15 in Australian service" by Stewart Wilson , Aerospace Publications 1991.
 

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In the last picture Justo posted it is interesting to note that the original R2800 version seems to have an eliptical trailing edge.
 
http://www.secretprojects.co.uk/forum/index.php?action=dlattach;topic=3846.0;attach=44751


it's from an early Air Enthusiast/International, can't rember offhand which one, i have it in a bound volume,IIRC either volume three, seven, ten eleven, or fourteen, can't check as my library's _still_ in store, :'( :'( :'( :'( :'( :'( :'( :'( :'(,

cheers,
Robin.
 
Red Admiral,

The two pictures you posted were ones I originally provided someone a while back - they are from "Wirraway, Boomerang and Ca-15 in Australian Service" by Stewart Wilson. The second of Justo's is from the same book.

If you want probably the best set of info on the Ca-15, get a hold of this book.

82e6_1.jpg


It has the entire development story including lots of pictures of mockups and other iterations. It also explains the reasoning behind the engine changes. It often becomes available on ebay - in fact there is a copy for sale on ebay Australia right now - see here:

http://cgi.ebay.com.au/BOOK-WIRRAWAY-BOOMERANG-CA-15-RAAF-WW2_W0QQitemZ170198417939QQihZ007QQcategoryZ4375QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Interestingly though, I believe the design shown in Justo's last picture as being the initial proposal is not. The original designs for what became the Ca-15 looked a lot more like the earlier Boomerang.

Regards,

Greg
 
Dear gentlemen, thanks a lot for that precious info

Antonio

(I'll see shipping costs for that book on eBay)
 
Member Abraham Gubler mentioned elsewhere that Commonwealth Aircraft was considering an original fighter design circa 1939. He describes this Wirraway follow-on as "an Australian-designed, highly-manoeuvrable, single-engine fighter similar to but more advanced than the ‘Zero’".

According to Abraham, a CAC designer had been personally involved with Mitsubishi's 12-shi program. An "‘Aussie Zero" would be superior to the Reisen because of presumed access to superior materials. The CAC project was rejected, the RAAF "remaining fixed on the [CA-11 Woomera] twin-engine single role aircraft".

Any other details on this fighter project?

Under "CAC CA-15 original design", Greg mentions that the initial CA-15 looked more like the Boomerang than the later R2800-powered concept. That suggests that nothing remained of the "Aussie Zero" concept by that stage.

http://www.secretprojects.co.uk/forum/index.php/topic,3846.0/

One final puzzle is designations. In the "Commonwealth aircraft" thread, Greg also covers every wartime CAC designation from the first CA-1 Wirrawy to the two-seat CA-21 Mustang. Were CA-x designations only applied to designs that had advanced fairly far along?

http://www.secretprojects.co.uk/forum/index.php/topic,1213.0.html
 
The person in question is Fred David, a German Jew who worked for Heinkel on the He 100 before being forced out by the Nazis. He then worked for Mitsubishi designing aerostructures for the Zero before finding a new home in Australia with CAC. He was later the Chief Designer on the Boomerang emergency fighter and the CA-15 fighter. The CA-15's original configuration was very much a He 100 with Pratt & Whitney R-2800s!

CAC proposed a single engine, lightweight fighter before the but was knocked back by the RAAF who didn't think single engine fighters had a future and the Government that was more interested in deals with the British Government with the Beaufort and Beaufighter. The best published source for information on this proposal is “Armed & Ready: The industrial development & defence of Australia, 1900-1945” by Andrew Ross. I haven't seen any information on the specifics of the design but they are no doubt there somewhere in the archives.
 
Apophenia said:
Under "CAC CA-15 original design", Greg mentions that the initial CA-15 looked more like the Boomerang than the later R2800-powered concept. That suggests that nothing remained of the "Aussie Zero" concept by that stage.

The CA-15 was always a start from scratch design with the R-2800 and never bore much similarity with the Boomerang which was just a fighter version of the Wirraway, itself a Texan. The design had three major stages, pre-Laminer flow wing, in which it was very much a He 100, post Laminer flow in which it was a big Mustang with a Double Wasp and final experimental stage in which it was powered by a Griffon. “Wirraway, Boomerang and Ca-15 in Australian Service” by Stewart Wilson has illustrations of the original CA-15 design.

If you look closely at the design progression below you can see on the first model you can just make out the pre laminar flow wing.

The ‘Aussie Zero’ was to be a new airframe and wing powered by the R-1830. The only similarity with the Wirraway/Boomerang was to be production techniques and some components.
 

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Boomerang/Kangaroo missing links
 

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Abraham: Many thanks for the details and clarifications. I now have a vision of an R1830-powered He-100 locked in my mind. Hopefully those archives will someday reveal detailed plans.

Justo: prolific as always! I love the P-176 especially -- very pugnacious. And those designations answered my other question, too. Obviously, the Zero-like design would have been assigned a P-xx numbers but, as it didn't get far, not a CA-xx number.

The people on this forum never cease to impress. Cheers!
 
With some luck Volume 2 of Keith Meggs' "Australian-Built Aircraft and the Industry" which is dedicated to devoted entirely to the history of The Commonwealth Aircraft Corporation ( see here might cover this a little more.

Regards,

Greg
 
Justo, do you also have a 1/72 scale drawing of the actual prototype CA-15 that was built? I've been looking for one for several years but to no avail.
 
As promised in another thread (AH R2800 fighters) here is the 17 pages of the CAC report A-102 of late 1944 into the final wartime design for the CA-15 fighter. This aircraft was to be fitted with the high power Griffon engine and differs from the flying prototype finished after the war with a much lower power Griffon engine. Performance figures are provided against the P-51H.
 

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Here are some more CAC drawings of the CA-15 design evolution from pre-laminar, Aussie FW-190 through to wartime Griffon version. Also some of the weapons options. These scans are from "Wirraway, Boomerang and CA-15 in Australian Service" by Stewart Wilson (see above) a series of books with loads of good information on RAAF aircraft (and what ifs). The book also has lots of imagery of CAC models, artwork and propriety three views which I haven't scanned.
 

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Volume 2 of Keith Meggs' "Australian-Built Aircraft and the Industry" has a few interesting tidbits on the CAC-15 that I did not know. Such as:

  • The Bristol Centaurus was also an engine option post the R2800-57W becoming unavailable
  • There was a proposal to do a Napier Nomad powered version as an entrant in the 1953 Sydney-Christchurch Air Race
  • In the 1970s there was apparently interest to build 3 R-2800 powered variants for Air racing and display purposes
 
Wow, that Nomad racer is not going to win. The Nomad was not a compact beast!

It wasn't. But frontal areas are surprising close between the Pratt and the Napier. The Nomad I had a frontal area of ~ 1.85 m2, the R-2800 about 1.80 square metres.

Now comparative lengths are another matter ... :D
 
Volume 2 of Keith Meggs' "Australian-Built Aircraft and the Industry" has a few interesting tidbits on the CAC-15 that I did not know. Such as:

  • The Bristol Centaurus was also an engine option post the R2800-57W becoming unavailable
  • There was a proposal to do a Napier Nomad powered version as an entrant in the 1953 Sydney-Christchurch Air Race
  • In the 1970s there was apparently interest to build 3 R-2800 powered variants for Air racing and display purposes
so it finally published, did it ?
 
Volume 2 of Keith Meggs' "Australian-Built Aircraft and the Industry" has a few interesting tidbits on the CAC-15 that I did not know. Such as:

  • The Bristol Centaurus was also an engine option post the R2800-57W becoming unavailable
  • There was a proposal to do a Napier Nomad powered version as an entrant in the 1953 Sydney-Christchurch Air Race
  • In the 1970s there was apparently interest to build 3 R-2800 powered variants for Air racing and display purposes
so it finally published, did it ?
In late 2020 I believe.
 
Boomerang/Kangaroo missing links
In 1942/43 the gov wanted cac to build a high altitude interceptor, "interceptor Boomerang, cac coming up with three options 1 the cac 14 boomerang with a turbo supercharger, option two with a Pratt and Whitney R-2000 wasp, or one with a wright r2600 twin cyclone. Producing 1700 HP. The Wright twin cyclone was to large and heavy for the boomerang and required a complete redesign. Thus the cac ca15 emerges, with either the wright R2600 or the Pratt and Whitney R2800 with 2000hp, so cac go with the 2000 HP r2800 which the Americans play keep away with the engine reserving it for its own fighters. CaC post war after Manny redesigns the cac ends up with the RR gryphon 61 after the UK plays keep away with the engine that cac originally wanted. So after all the redesign the cac ca15 concept ended up with a 1700 HP engine in the last days of reliance of prop fighters.
 
Packard Merlin was used in Ocker built P-51's.

Latter versions would have been close, considering the reduced weight in those engines and they did good enough service in the P-51.
 
Comparison drawing showing R-2800 and Griffon engine designs.

Picture of mockup with R-2800 engine.

I'm afraid I can't remember the source.
Not technical, but that may be the most gloriously front-heavy aircraft I have ever seen. Not counting early jet-fighters.
 
  • In the 1970s there was apparently interest to build 3 R-2800 powered variants for Air racing and display purposes
How did I miss this the first time around? I like it! Great model fodder.
 
While not a R2800 version, Damian did a fictional race version for me years ago - and despite multiple attempts to post it here it won't show. You can see it here though - go to the link and then scroll halfway down the page looking for the Strega racer.
 
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One of the E.European manufacturers was working on a 72 scale kit of the CA.15, not sure of its current status
 

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