WesWorld

I've mentioned this elsewhere, and decided to post it here since I've got a fairly polished drawing to show off.

Starting in late 1940, ENAER will be designing the following airplane for first flight in 1944. The FACh's RfP to ENAER requests the following traits:
- Primarily designed for ground attack and direct support of land forces (COIN)
- Capability to act as a fighter aircraft
- Need for short-field operation
- High altitude and desert operation
- At least 2,000 pounds underwing ordnance: must include options for under-wing cannon pods, torpedoes, bombs, and rockets
- Excellent visibility, particularly over the nose
- 375mph or more at altitude
- Potential for adoption as carrier-based aircraft

This aircraft will probably replace the I-01-IIB (F1E) Buchon fighter-bombers in the II Brigade and III Brigade (I Brigade will be equipped with dedicated air-superiority/interceptor types, rather than strike fighters), and probably the aircraft in the 1st and 2nd Attack Regiments as well. In this case, the FACh would probably acquire quite a large number of these aircraft; the Navy would presumably be similarly interested if a carrier-capable version was available.

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This drawing is based on other drawings by Vukovlad, Red Admiral, Hood, and myself.

[SIZE=4]ENAER Kodkod Close Air-Support Fighter[/SIZE]
[SIZE=3]Specifications[/SIZE]
Wingspan: 34.15 ft (10.4 m)
Length: 41.35 ft (12.6 m)
Height: 13.1 ft (4 m)
Wing Area: 408 ft² (37.9 m²)
Empty weight: 9,000 lbs (4,082 kg)
Loaded weight: 14,000 lb (6,350 kg)
Engine: 1 × Austral Malacara-SP3 turboprop (2,450shp) or some sort of V-frame engine
Crew: 1

[SIZE=3]Performance[/SIZE]
Max speed: 400 mph (347.6 knots / 643.7 kph)
Range: 1,000 mi (1,609.3 km)
Service ceiling: 37,500 ft (11,430 m)
Rate of climb: 5,000 fpm (25.4 mps)
Wing-loading: 22 lbs/ft² (empty); 34 lbs/ft² (loaded)

[SIZE=3]Armament[/SIZE]
- 8 × Underwing mounts for bombs, rockets, or MG pods (up to 2,250lbs).
- 1 × centerline mount for torpedo, heavy bomb, or belly fuel tank

[SIZE=3]Notes[/SIZE]
Kodkod development started in 1940 with a request for a dedicated ground attack aircraft. ENAER's senior project manager Alexander von Ahrens elected to design a "close air support fighter" equipped with a 2,450hp Malacara-SP3 turboprop engine. The first "Kodkod" flew in late 1943, and deployed operationally by early 1945.

Normal armament will probably end up being some combination of:
- 4x1.1" cannon + 4 bombs or rockets
- 2x1.1" cannon + 2x13mm MGs + 4 bombs or rockets
- 8x13mm MGs
- 2x1.1" cannon + 6 bombs or rockets
If the centerline mount has a torpedo, then I believe only 2-4 wing mounts should be used.

The specs at the moment should be referred to as probable guidelines rather than concrete dogma; I feel the performance should be acceptable but I'm willing to raise or lower the figures based on discussions.

The thought of Chile building production ready turboprops (of quite considerable SHP) by 1945 is still troubling me. That would be a good 2-3 years in advance of the Great Powers. Would Chile recognise any potential advantages in the turboprop in 1940? Would the Air Staff officers drafting this spec even have heard of a turboprop in 1940?
I could think of several piston engines of equal performance that would be ready by 1944.

Overall it looks damn mean and very powerful. FMA I think will be looking a something very similar but with a piston engine.

Hey Avalma, you sure you don't want to put my designs in production?

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Originally posted by Hood
The thought of Chile building production ready turboprops (of quite considerable SHP) by 1945 is still troubling me. That would be a good 2-3 years in advance of the Great Powers. Would Chile recognise any potential advantages in the turboprop in 1940? Would the Air Staff officers drafting this spec even have heard of a turboprop in 1940?
I could think of several piston engines of equal performance that would be ready by 1944.

As to the turboprops - historically, Jendrassik got the Cs-1 to generate approximately 400 hp on the first test run in 1940, and the Hungarians planned to put it into service on the RMI-1 fighter. Of course, that engine was supposed to generate a thousand horse, so it was somewhat disappointing; and the engine was sidelined as a result of WWII and the Hungarian purchase of the Me-210. Hungary's not exactly a Great Power, but it seems to me that the Hungarians could have gotten a working turboprop-powered heavy fighter by 1942 or so, if circumstances had gone differently.

In Wesworld, there are several factors here. First, Austral licensed the design of the Cs-1 from Rolls-Royce, and has already constructed and operated a scaled-down (300hp) version on a test stand - the Austral Babieca. The Babieca is a test engine only - it'll fly in trials on a Twin Condor, but never enter production. Second, Austral's chief engineer, Fernando Pernet-Sharpe, started researching turboprops in 1938 (I think it's in my news somewhere) and corresponds regularly with Jendrassik in Britain - and he'll be visiting him in Q3, as I've noted elsewhere. Pernet-Sharpe has already started working on designs that will eventually become the Austral Malacara. Third, Austral is substantially owned by Roth-Packard and so has access to Roth-Packard's R&D fund, as well as access to the Atlantean research into turbojets (which Roth-Packard is currently leading). Per my discussions with Wes, Roth-Packard received responsibility from the Advancing Technology Development Committee (ATDC) to take care of all turboprop-related research for Atlantis, and all of that research was assigned to their Austral division, as Pernet-Sharpe was already working on turboprop projects.

The Kodkod is not designed to be specifically matched with the Malacara turboprop - I'm open to using a more historical V-bank engine, so long as it provides similar-ish capabilities. If the widespread consensus is against deploying the Malacara SP3 for first flight in 1944 and series production in 1945, then I'll hold off a bit - but I shall not give it up, just delay it until it's more acceptable.

I'm not after a super-engine; if I was, then I'd have taken the existing 2,100hp Austral Incitatus - a licensed Roth-Packard engine - and made a four-row 28-cylinder radial out of it. Oops, 4,200shp!

Frankly, by the time this plane makes it into production, it'll be mostly outmoded as a fighter anyway; I'll probably be able to buy second-gen jet fighters from FAR or the US or the UK by then, so I'm not going to throw a fit over a second-line strike fighter.

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Originally posted by Hood
Overall it looks damn mean and very powerful. FMA I think will be looking a something very similar but with a piston engine.

Thanks!

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I'm not after a super-engine; if I was, then I'd have taken the existing 2,100hp Austral Incitatus - a licensed Roth-Packard engine - and made a four-row 28-cylinder radial out of it. Oops, 4,200shp!

Why not go a little bit further and use something like the Nakajima Ha-54? After all, 5,000 is a nice figure.

I like the Kodkod a lot. Lovely lines and a nice color scheme.

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If the centerline mount has a torpedo, then I believe only 2-4 wing mounts should be used.

I am certain you can use them all. Will it get off the ground then? Well, that is another matter.

Give it a large enough engine and I believe that it will get off the ground.

Martin Mauler

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Originally posted by BruceDuncan
Give it a large enough engine and I believe that it will get off the ground.

Martin Mauler

Oooooooh, shiny!

I think the main problems with period turboprops is that they simply won't be as good as for a piston engine. Unlike today, you don't have sufficient reduction in weight and volume to make up for the increase in sfc. A period turboprop will be quite large, heavy, and have very poor sfc (as in ~50-100% worse than a piston engine). In combination with this is simply the issue with getting the thing to work reliably, which is no small thing. From looking at the CS-1 this is really going to take some doing given the massive complexity involved. Another issue is making it; there are lots of small compressor and turbine blades to be precision made, which is rather difficult. This was still a stumbling block for the UK in Korean war times.

Altogether, I don't really see any advantages over a piston engine to make it worth the effort. For COIN/CAS, I would have thought the poor loiter performance would make it a no no straight away.

Overall, I do quite like the look of the aircraft. It should be pretty useful.

I'm not quite convinced about the performance unless there are a few typos in there. Is the wing area of 408 sq ft right? This means your aspect ratio is 2.85 which is extremely low. You'd probably want 6-7 instead. If that wing area is correct, I'd see it being considerably heavier, slower, and climbing slower. With a wing that big you're getting up into the territory of the A-1 or Blackburn Firebrand.

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Originally posted by klagldsf
Hey Avalma, you sure you don't want to put my designs in production?

I'll ofcource, I'm still working on them!!!!!


btw

Looks great Brock

At a time where the jets not jet seem powerful or reliable enough to drive a plane alone, a turboprop is an interesting option - in OTL and WWTL.

The above design reminds me a lot of the ill-fated Dougles A2D Skyshark. Probably a smaller, less powerful predecessor? ;o)

I think Hood has a valid point, questioning whether the Chileneans would really take the risk and investments or use a piston engine instead in 1940. And reading about the OTL troubles with engines like the Skysharks Allison XT-40 and its gearbox, I have doubts Chile can deploy such plane operationally in early 1045. It´s probably a bit early even though you have Atlantean support - which raises the question why Atlantis should put its money on this field of technology that early and how this could be compared to OTL.

However, I have to weaken my own argument as the era of early jets and turboprobs is grey and shady for me. Probably the Allison engine of the A2D is simply not a good example. But I can´t help but think that a piston engine aircraft like the Skyrider is a much better choise for Chile...

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Originally posted by Red Admiral
I'm not quite convinced about the performance unless there are a few typos in there. Is the wing area of 408 sq ft right? This means your aspect ratio is 2.85 which is extremely low. You'd probably want 6-7 instead. If that wing area is correct, I'd see it being considerably heavier, slower, and climbing slower. With a wing that big you're getting up into the territory of the A-1 or Blackburn Firebrand.

I went back and looked at my base aircraft more closely, and I think you're probably right - the wing area seems dramatically aberrant from normal. Obviously I used the wing from the I-02 drawing, and the I-02 wing is 197 ft²... so I think I'll have another look at the specs.

As to the engines - I presume that for this sort of aircraft layout a radial engine would be a bad choice. What sort of inline do I need to get roughly this sort of performance? I presume (again) that by 1944 Spartan will have an inline engine of approximately 2,000 - 2,500 hp that I could use.

Actually, I think a radial engine would make better sense than some sort of a buried inline - of course, it would change the CG and sit of the aircraft - but it would be the technically less complex.

As to performance - getting any sort of piston-engined strike fighter up to 400mph is going to take some doing. Something in the 3500hp class would be minimum, given the structure required to carry the ordnance loads you are looking at.

Historically, single piston strike fighters of this sort were few in numbers - the Blackburn Firebrand and the Westland wyvern being examples. Their service careers were less than stellar.

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Originally posted by BruceDuncan
Actually, I think a radial engine would make better sense than some sort of a buried inline - of course, it would change the CG and sit of the aircraft - but it would be the technically less complex.

I'm rather under the impression that inlines were always used in buried applications (as well as pusher configurations) because radials have more issues with cooling in these locations. Is that incorrect?

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Originally posted by Brockpaine

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Originally posted by BruceDuncan
Actually, I think a radial engine would make better sense than some sort of a buried inline - of course, it would change the CG and sit of the aircraft - but it would be the technically less complex.

I'm rather under the impression that inlines were always used in buried applications (as well as pusher configurations) because radials have more issues with cooling in these locations. Is that incorrect?

I'm suggesting scrapping the buried engine altogether and hang the radial at the none. Supposedly the Tupolev Tu91 design had a buried engine configuration, but I do not know if metal was ever cut on that project.

Piaggio P.119 is the best example of a buried air-cooled radial engine. It gives a very large fuselage and a prominent ventral air intake for cooling (along with a fan for forcing more airflow). Tu-91 was built in prototype form but is a turboprop.

If you're looking at an aircraft this size (from the earlier specs), i.e. rather lighter than the Firebrand/Wyvern, then ~2500hp should be fine for ~400mph at low level. With external weapon loads and pylons the speed would drop quite a bit.

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Originally posted by BruceDuncan

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Originally posted by Brockpaine

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Originally posted by BruceDuncan
Actually, I think a radial engine would make better sense than some sort of a buried inline - of course, it would change the CG and sit of the aircraft - but it would be the technically less complex.

I'm rather under the impression that inlines were always used in buried applications (as well as pusher configurations) because radials have more issues with cooling in these locations. Is that incorrect?

I'm suggesting scrapping the buried engine altogether and hang the radial at the nose.

That would pretty much require a complete re-draw of the plane and it would presumably ruin the excellent forward visibility which I wanted to start with.

Redraw with inline rather than turboprop.

The RR Eagle powered Wyvern will feature on my future carrier decks. Actually had more development occured it might have been pretty good at its job. The switch to turboprops did it no real favours though it wasn't a total dog.

An interesting and very useful aircraft. A turboprop version could be around for quite some time (ala P-51/PA-4. Gotta say, working on turboprops while condemning my own jet program, well...

The XP-56 used a buried P&W R-2800. So it is possible to used radials. Thought the mid mounted location reduces the vulnerability of a liquid cooled engine to ground fire. FW-190's could carry torpedoes and up to 4,000 lb bombs, so 2,000hp should be sufficient for this aircraft.

What is the nose scoop for? Have you considered sticking a heavy cannon in the nose (ala p-39)?. Will it have any armor (Fw-190/P-63)?

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Originally posted by Desertfox
What is the nose scoop for?

It's a semi-annular radiator; the design cue came here from a modified version by RA. While I initially hated it, it really grew on me and I modified it somewhat.

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Originally posted by Desertfox
Have you considered sticking a heavy cannon in the nose (ala p-39)?. Will it have any armor (Fw-190/P-63)?

No to the former, yes to the latter. I was planning for a potential of 4x1.1" cannon in wing pods, plus HVARs when they come out. At least at the moment, I'm not aware of any tank in South America that could laugh off strafing hits from 1.1" cannon; while this of course might eventually change, I see no reason to add anything bigger at the present time.

As to armor - yes. Chile is a firm believer in bringing back their valuable pilots safely. Therefore the plane will be armoured.