Beyond The Sprues
Current and Finished Projects => Physical Models => Aero-space => Topic started by: kitnut617 on June 03, 2020, 06:43:53 AM
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In my other mid-engine Wyvern thread I mentioned I'd do a turbo-prop variant which would be powered by a RR Tyne. I had thought about using one of the other CMR TF.1 kits I have, but I recently got hold of a Trumpeter 1/72 Wyvern S.4 which made the partly built old Frog kit redundant.
Until I started thinking about what I needed to do to make a S.6.
So here's the idea ---- as it's will be designated a S.6c, I'm saying the Tyne was one of the most powerful version, say around 6800hp ---- to absorb that power a pair of De Havilland wide chord 3-blade props in contra-prop form were used.
I put this together over the last couple of days so I can get a real idea what it's about. Because the engine is mid mounted, the exhaust pipe will be moved further to the rear, one photo here shows I've cut the starboard side one out and filled it in with styrene card, while the port side one still has to have the work done.
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Looking good Robert! :smiley:
And that forward-placed cockpit really does make sense for a carrier aircraft.
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Thanks Stephen
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Almost requires a nose wheel... ;)
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I've been refining it, I've shortened the nose by 6mm ;)
The idea is that the RN didn't can their carriers and the Wyvern's swan song was the Falklands --- going to be XDSG over white, still armed with the Oerlikon 35mm revolver cannon, but with four of them and four Martel/Sea Eagles on pylons (maybe a pair of each)
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I've been refining it, I've shortened the nose by 6mm ...
Was that by pushing the white/beige bits aft into the blue bits? (Sorry for all that technical lingo.)
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I've been refining it, I've shortened the nose by 6mm ...
Was that by pushing the white/beige bits aft into the blue bits? (Sorry for all that technical lingo.)
Yes, I trimmed off 6mm from the white part where it joins the blue bit, that's up the sides, over the top and also under the fuselage. I thought that there was too much overhang which put the prop way out in front.
At first I was trying to make it so that I would use a Python engine, but with the air intake for that engine being right at the back end, meant it would have to have some sort on intake/duct at the rear end of the fuselage, just in front of the exhaust. So then I thought about it would be Clyde powered, but in the end, changed my mind and went with the Tyne. The Clyde/Tyne route makes for a much tidier looking aircraft with the intake under the spinner, which also gives it a similar appearance as the TF.1/SF.4 has.
The tail surfaces on the original S.4 Wyvern are massive, way bigger that the TF.1 tail surfaces. But I did re-profile the fin slightly at the top to make it look like the TF.1 fin, but still keeping it quite a bit bigger. Once I get it a bit further advanced, I'll take some comparison pics.
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Here's some updated pics
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Good call on shortening the front. That looks much more practical - you can imagine this aircraft taking the wire without chewing up the decking :smiley:
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Thanks.
The forward fuselage is now the same length as my first Wyvern, measured from the rear of the spinner to the wing root leading edge. The difference now is the longer spinner the wide blades need but then the prop center line has moved up about 3mm because of what I used for the new forward fuselage, which is a F-86K nose conversion off an Air Model sheet. The cockpit has been suitable moved forward though --- ;)
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I've got it mostly glued together and a coat of undercoat so I can see what I need to fix up. I'm also thinking of a different camo scheme, especially after looking at the light grey finish the undercoat has --- how about in Barley Grey ?
Still working on the exhaust positioning though ---
I've also revised what the loadout will be, first, the wing pods will have AN/APG-53A Air to Air/Air to Ground targeting radar with its associated ground avoidance and weather radars, it will have an AN/ALQ-131 ECM pod on one of the outer pylons, with the other outer pylon having a twin launch rail with Sidewinders, the inner pylons will have one MARTEL on each one, and for fixed armament, a single Oerlikon 35mm revolver cannon in each outer cannon bay, the inner cannon bays being deleted and the space used for wing tanks. The center pylon has a 450 Gal drop tank.
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That looks the business! Very nice :smiley:
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:smiley:
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Thanks Stephen, Greg ---
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Lookin' very cool so far! 8) A British Skyshark, sorta. :smiley:
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It's got the look hasn't it Moritz , cheers -----
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I've been playing with camo schemes, I gave the S.6c a coat of Barley Grey just so I could see what it might look like. I've also played with an idea for the spinner.
These two pics show what I did, plus it shows how the exhaust nozzle is orientated --
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It's got the look hasn't it Moritz , cheers -----
Well, maybe Skyshark's better-looking sister ;)
Liking the exhaust position :smiley:
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Cheers Stephen ----
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Still getting my head around the different lines of a Wyvern, but terrific work getting it to meld so well
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Thanks buzzbomb
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Can see Wyvern S.6c and Skyshark competing in RAN flyoff. Has look where can be on model show table with RW type paint and fool some as being the real deal. :smiley:
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An evil plan is forming in the little grey cells ----- >:D >:D >:D
Thanks Bill ----- I need to find another Frog Wyvern (although I could use a Trumpeter kit)
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After a lot of PSR and getting the exhaust to look right, the model got really tatty so I gave it another quick coat of paint ---- and just so I could get my head around it --- in overall XDSG
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Well the engine move certainly changed the lines, but it does work and has a mean look around it
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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 ----
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I've been plugging away at this, got it on it's wheels now.
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Noice! :)
Out of curiosity, why 35 mm Oerlikons instead of ADENs? Were your alternative RN ships kitted out with GDF-001s?
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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.
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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 ;)
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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
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... 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).
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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.
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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