Author Topic: Westland Wyvern S.6c - Mid-Engine (take 2)  (Read 810 times)

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #25 on: June 22, 2020, 11:24:36 PM »
Thanks again buzzbomb.

I've decided to revise the fixed armament arrangement, I'm sticking with the Oerlikon 35mm cannons but moving them into the forward fuselage, they would be synchronized to fire through the propeller arc. Then I'll have a single 30mm ADEN in each of the outer wing gun bays. Should be enough to ruin any ground target's day ---

I'm now leaning towards the XDSG --- I think overall XDSG, with a red on the spinners much like how it's painted now, front spinner mostly red, the rear spinner mostly XDSG. I've got some Harrier decals with an option for NAS 800 which has a larger red flash for the fin (called a 'speed bird' I think). That should work ----
« Last Edit: June 22, 2020, 11:29:38 PM by kitnut617 »

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #26 on: June 28, 2020, 12:51:20 AM »
I've been plugging away at this, got it on it's wheels now.

Offline apophenia

  • Patterns? What patterns?
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #27 on: June 28, 2020, 10:38:59 AM »
Noice!  :)

Out of curiosity, why 35 mm Oerlikons instead of ADENs? Were your alternative RN ships kitted out with GDF-001s?
"And loot some for the old folks, Can't loot for themselves"

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #28 on: June 28, 2020, 10:24:37 PM »
Hi Stephen,

I took this below out of my thread about the Eagle engined Wyvern on the What-If Forum.

The loadout for this has been an evolutionary process as I built the model. The idea being this is an SF-1 (A.S.), Strike Fighter.1 (Anti-Ship) Originally, I was going with the four Hispano 20mm's, the 200 Gal drop tank on the centerline, and a full sixteen RP3's with 60lb warheads. That changed with me adding Firefly slipper tanks under the outer wings which have AN/APS-4 radar scanners in them, and then the RP's became eight Triplex RP's and two Vickers 'S' 40mm cannons in underwing pods. I decided against using the Vickers cannons and thought maybe the internal wing cannon could be ADEN 30mm's, but after reading up on the ADEN and learning they are 'revolver' cannons, I then started investigating if there was a larger revolver cannon made. Turns out Oerlikon has a line of anti-aircraft cannons of 35mm and are also revolver cannons. One type was the KDB, which was a 'light-weight' version of the KDA, but for use as armoured vehicle turret guns. This led to me having a what-if development of the KDB made specifically to mount in aircraft, I've added modified gun bay access panels which have bulges top and bottom of the wing, then I had to come up with a story of where the ammo gets stored, but not many rounds I think, maybe be lucky if 160 rounds per gun even though it has a rate of fire of 1000 rnds.p.m. So about 10 seconds worth of firing time. I read that the Oerlikon anti-aircraft cannons fire in 28 round bursts so my thinking is this would be the same.

Then I was re-reading the 4+Productions bookazine on the Wyvern, and came to the part which had photos of various loadouts the Wyvern was tested with. One type was an enormous FFAR RP of 11.25" diameter and weighed 1000lb. It was code named Red Angel. As it was tested on a Wyvern and I wanted to find out more about it, so out came the BSP, Hypersonics, Ramjets & Missiles book to see what was in there. Quite a bit apparently and pleased to see it was earmarked as an anti-ship missile too, there was also a 4-View drawing of it which I scanned and scaled.


So I just continued with the 35mm in this build. What I was looking for is a 'modern' 40mm and the closest I could find was the Oerlikon (it had to be a western gun too, not something soviet made). Mind you, your suggestion about the GDF's would make a lot of sense if the rounds were the same. But I'm thinking the 35mm's in the Wyvern would have mostly armour-piercing rounds.
« Last Edit: June 28, 2020, 10:45:57 PM by kitnut617 »

Offline apophenia

  • Patterns? What patterns?
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #29 on: June 29, 2020, 09:12:52 AM »
Cheers Robert. Okay, so the KDB ... which is the individual component for some of the GDF-series twined AA guns.

BTW, your quoted rof of "1000 rnds.p.m." is for the twin-gunned GDF series. The single-bbl KDB would be 550 rpm. You also mentioned "160 rounds per gun" but, FWIW, the standard RW KDB belt-length is 56 rounds (though easily changed, of course).

Some other numbers (just in case they are of interest):

Weights, Gun Only : KDB = 1,532 lbs; 2 x Hispano V = ~180 lbs; 1 x ADEN = 176 lbs.

Weights, per Round: KDB = 3.45 lbs ; Hispano V = 0.56 lbs ; ADEN = 0.97 lbs

Ammunition Size : KDB = 35 x 228 mm; Hispano V = 20 x 110 mm ; ADEN = 30 x 113 mm

A RW Wyvern carried 400 rounds per wing weighing ~224 lbs (less links, boxes, etc.) plus gun weights of ~180 lbs for a total of about 405 lbs (less links, mounting hardware, and other ancillary bits) per wing.

With no increase of weight, each wing could handle one ADEN plus 230 lbs of ammo and hardware. (To get an idea of complete weights, 30 rounds of boxed and linked 30 x 113 mm weighs about 48.5 lbs - of which, only 29 lbs is actually ammo weight. So, maybe ~140 rds of 30 mm per wing?)

So, each KDB weighs roughly 8.5 times as much as the original pair of Hispanos. Mounted, a standard belt of 56 x 35 mm rounds will weigh another 320 lbs (193 lbs of actual ammo). Add to that, you need to brace for recoil forces of 5,840 lbs per gun (vs 880 lbs for each of the Hispanos).

Anyway, your Tyne variant should have huge power reserves. With enough structural strengthening, I don't thank any of these weight numbers are deal-killers. And that KDB mount does suggest a handy Bofors replacement for shipboard use as well  ;)
"And loot some for the old folks, Can't loot for themselves"

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #30 on: June 29, 2020, 10:34:22 PM »
Nice Stephen,  :) :) :)

I think I'll stay with 1000 r.p.m., ** mainly because the 30mm ADEN's rate of fire was 1300 r.p.m. (early ones) and the Oerlikon shell is only 5mm bigger although admittedly, the cartridge is quite a bit bigger. But as I wrote, the aircraft mounted version is a what-if scenario, modified somewhat for the application. But you're right, it is still a big gun, mine measures at least 11 feet long, mostly in the barrel.

How do the numbers compare to the Vickers S 40mm ?

** EDIT; I'll revise that, keep it more realistic. The rate of fire will be 550 rnds.p.m
« Last Edit: June 29, 2020, 11:30:08 PM by kitnut617 »

Offline apophenia

  • Patterns? What patterns?
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #31 on: June 30, 2020, 05:05:10 AM »
... How do the numbers compare to the Vickers S 40mm ?...

Robert: Here's a few numbers together comparing the 'S' Gun with KDB. I've added in the COW Gun (OQF, 1 1/2 pdr, Mk III) for comparison - since the 'S' was effectively a short-barrelled version of the long-recoil COW Gun re-designed to take Vickers' 2-pounder 'Pom-Pom' ammunition in place of Coventry's longer rounds.

Weights, Gun Only : KDB = 1,532 lbs; COW = ~200 lbs; 'S' Gun = 320 lbs

Weights, per Round: KDB = 3.45 lbs ; COW = 1.43 lbs; 'S' Gun = 3.97 lbs

Ammunition Size mm: KDB = 35 x 228B; COW = 37 x 190R; 'S' Gun = 40 x 158R

Length, Total Gun : KDB = 15.55 ft ; COW = 7.64 ft ; 'S' Gun = 9.74 ft

Length, Gun Barrel: KDB = 10.33 ft ; COW = 6.23 ft ; 'S' Gun = 5.57 ft

Cyclic Rate of Fire: KDB = 550 rpm ; COW = 90 rpm ; 'S' Gun = 100 rpm

Magazine Capacity : KDB = 56-rd belt; COW = 5-rd clip; 'S' Gun = 15-rd drum

Muzzle velocity : KDB = 3,855 ft/s ; COW =  ft/s ; 'S' Gun = 1,870 ft/s

A few anal-retentive notes:

The 200 lbs usually quoted as COW Gun weight included the mount (I haven't been able to find a 'gun only' weight for the COW Gun).

In the suffixes on ammunition, 'R' is for Rimmed, 'B' is for Banded (referring to the copper driving-band which surrounds the steel projectile).

Cyclic rof are a bit of a nonsense. Obviously, no-one ever got 90 rpm out of a COW Gun using 5-rd clips!

On ammunition capacity, the 'S' Gun began with a 12-round drum but service types had 15 rounds. There were unrealized plans to ditch the drum in favour of belt-feed.

You will see muzzle velocities for the KD series of up to 4,725 ft/s ... but that's for APDS ... and you don't really need your turboprop hoovering up discarded sabots  :o  Muzzle velocity listed for the 'S' Gun is for AP Mk.VI (m/v for the lighter AP Mk.I rounds would be higher).
"And loot some for the old folks, Can't loot for themselves"

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #32 on: June 30, 2020, 05:54:48 AM »
Thanks again Stephen.   :)

Even though the Triple AAA KDB weighs quite a bit, I'm sure a version for installation in aircraft could be quite a bit lighter, plus the overall length of it shorter as the distances from firing to target could/would be much closer that what a anti-aircraft gun has to be able to shoot at. As you mentioned further up the thread, the KDB is a twin gun, does that mean a single gun is half that weight, so about 766lb per gun ?

EDIT:  Ok just found a spec sheet for the KDB, 959lbs --- that's a bit more like it

https://weaponsystems.net/system/283-35mm+Oerlikon+KDA

So one modified for aviation installations could be lighter.
« Last Edit: June 30, 2020, 06:02:01 AM by kitnut617 »

Offline apophenia

  • Patterns? What patterns?
Re: Westland Wyvern S.6c - Mid-Engine (take 2)
« Reply #33 on: June 30, 2020, 08:21:57 AM »
Certainly it could be reworked for aircraft use. A RW lightweight version of KD series already exists - it is the KDG (formerly the 35/1000) revolver cannon component of the Millennium Gun CIWS (now Rheinmetall GDM-008). It has since been offered in a SPAAG turret (but no airborne version AFAIK).

KDG compares with KDB as follows:

Gun Weight: KDB = 1,532 lbs; KDG = 992 lbs
O/A Length : KDB = 15.55 ft ; KDG = 13.48 feet
Barrel Length: KDB = 10.33 ft ; KDG = 9.074 feet
"And loot some for the old folks, Can't loot for themselves"