1:72 Avia NS-92A; Israeli Air Force, 119 tajeset, Tel Nov 1955

Dizzyfugu · August 13, 2019, 01:03:21 AM

In the meantime, while waiting for parts for my next "More or less engines" GB project, I tackled this interim project: the Avia NS-92 night fighter for Israel.

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

Some background:
The Messerschmitt Me 262 was the world's first jet fighter to enter production, the first to enter full squadron service, the first to score an air-to-air victory, and is easily one of the WWII Luftwaffe's most famous planes.
During WWII, Germany used the facilities of Avia in occupied Czechoslovakia to sub-contract parts for the Me 262 and planned to start full production of the fighter there. The western part of Czechoslovakia was liberated in the conflict's final 96 hours by Soviet troops, in the last battle of WWII in Europe, and the commandeered aviation production facilities were captured intact. After the end of the war, the Czechoslovak air force decided to restart production of the Me 262, designated Avia S-92 (S for Stíhač, meaning "fighter").

The S-92 was an exact clone of the Me-262 and nearly identical in all respects. Although no completed pattern plane was available, the Czechoslovaks had complete blueprints, some completed sub-assemblies and a wide variety of parts at their disposal, together with the technical manuals and, most importantly, the production jigs and tooling needed to build the Me-262. In late 1945, it was decided to have Avia commence production of the Me-262. The airframe and flight controls were manufactured in kit form by Avia, the Junkers Jumo 004 turbojet engines were re-designated M-04 and manufactured by Avia's Malesice Engine Repair division. The whole plane itself was basically hand-assembled by workers at the Letnany Research Institute, so that S-92 production was neither easy nor fast: each individual plane took about 7,000 man-hours to make.

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

The armament was the same as the WWII planes, four MK 108 30mm guns in the nose. The MK 108 was an exceptionally hard-hitting aircraft gun, in an era when most fighters were still armed mainly with .50cal machine guns. Just a few rounds were enough to take down a four-engined bomber, even though the weapon's range and accuracy were rather limited. All of the guns that were originally mounted onto the Avia S-92s were actual German WWII-manufactured MK 108s. The Me 262's optional underwing rocket racks were omitted, since the respective R4M missiles were not available anymore, but the ventral hardpoints for bombs and – more important – drop tanks were retained.

Production of the first S-92 started at the end of 1945 and ran into early 1946. After last-minute checks, Avia transferred the first S-92 to the Czechoslovak air force in June 1946 and the type first flew on 27 September 1946. The plane crashed three days later, though. The second S-92 first flew on 24 October 1946, and it was the first to enter squadron service. All of the few S-92s built for the Czechoslovak air force were assigned to a special all-jet subunit of the 5th Fighter Squadron, which was based at Kbely airbase near Prague, being tasked with air defense of the capital.

Early into the project, it became obvious that a conversion trainer would be needed, and three two-seat models were built, which were designated CS-92 (C for cvičení, meaning "exercise"). They were essentially identical to the S-92, except that a second seat replaced some of the fuel. The first CS-92 (the third airframe overall) was delivered in September 1946 and first flew on 12 October 1946. A total of three CS-92s were built for the Czechoslovak air force.

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

In general, the Czechoslovak air force's findings with the S-92 were the same as post-WWII evaluations of the Me-262 by the USA and Great Britain: It was, of course, much faster than the WWII-design propeller fighters it served alongside in the late 1940s. For example, the La-7 "Fin", the fastest Czechoslovak piston-engine fighter at the time, was almost 150 knots slower, but the S-92 was less maneuverable when going into a turn than the La-7. However, as a jet it maintained its lift through the turn, whereas a propeller-driven types tended to "bleed off" lift during the maneuver. Otherwise, once the pilot had mastered the plane, the S-92 was still, even in 1948, a very good fighter.

Nevertheless, the type's major weak point was the engine. The M-04 needed to be maintained before and after every flight and it had an overall lifespan of only 60 flight hours. This was twice as long as the German Jumo 004 in war times, but this could rather be contributed to the fact that, in peacetime, the Czechoslovak pilots could gingerly work the throttles while taxiing and during the initial climb, whereas the Luftwaffe pilots needed to get the plane into the air as fast as possible. Another factor was higher quality material. Once the engine hit its lifespan limit, it could be factory-rebuilt, but Czechoslovaks found that the M-04 suffered from a type of metal fatigue called creep, and this was inherent to the Junkers design with no fix. After roundabout 300 hours of total flight time, it was not possible to refurbish the engine anymore and it had to be scrapped.
Despite being a WWII design, two countries showed interest in the post-war Avia S-92. Yugoslavia was the first potential customer, and in 1947, a Yugoslav air force pilot was trained in Czechoslovakia on the type. The Yugoslavs were interested in having a small number of jets to back up their mixed bag of propeller-driven fighters (P-47 Thunderbolts, Yak-9s, and Ikarus S-49s), but after reconsideration they decided to stick with piston-engine designs only for a few more years, with the goal of getting a new top-line American-made jet later. This became the F-84 Thunderjet, and this type eventually entered Yugoslav service in 1953.

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

Israel was the next prospect. In 1948-1949, there was some serious interest by Israel in either placing a production order with Avia or simply buying all of the few completed planes immediately for cash. Like Yugoslavia, the IDF regarded the Me 262 clones only as a stopgap solution, but the aircraft also played an important role in a deceptive political plan, which eventually worked: In 1950, Egyptian intelligence reported that a jet fighter had crashed at Ekron airbase inside Israel (the Israeli air force was still all-piston powered at the time) and that it most likely was an S-92. Sometime later, an Egyptian transport plane reported that it was being harassed by what appeared to be "a Me-262".

Behind the scenes, the IDF had secured a secret deal to import not only the S-92 day fighter, but also the CS-92 trainer and a new, dedicated night/all-weather fighter variant called NS-92 (N for noční, meaning "night"). The latter was based on the CS-92 two-seater, similar to the German Me 262 B-1a/U1 interim night fighter, but it lacked dual controls in order to save weight. However, the NS-92 carried a more advanced radar system than the Me 262 B-1a/U1's FuG 218 Neptun radar with a draggy eight-dipole antenna array, namely a revised FuG 240 Berlin system, which was copied by America after the end of the war as the AN/APS-3, which was, among others, used on board of the North American P-82F Twin Mustang.

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

The FuG 240 was an advanced design and used a more effective and less draggy dish antenna. It operated in the 3,250–3,330MHz (~10 cm) frequency band and its power output was 15 kW, making it effective against bomber-sized targets at distances of up to 9 kilometers, or down to 0.5 kilometer, which eliminated the need for a second short-range radar system. In order to mount the rotating dish antenna under a spacious radome on the Me 262's airframe, the whole nose section had to be re-designed. A large fiberglass fairing was installed, which lengthened the fuselage by almost 3' (80cm). Since the radar equipment now occupied the whole space above the front wheel bay, the internal guns had to be relocated into a low position, with two staggered cannon on each side, flanking the front wheel well (see below). Despite the new nose's bulky shape, the new arrangement was aerodynamically far more effective than the Me 262 B-1a/U's large dipole "antlers" antenna array, and the fighter almost regained its pre-radar speed. The only major drawback was a limited field of view for the pilot, especially directly in front of the aircraft.

The S-92/Me 262's original 30mm MK 108s were not mounted anymore: while the MK 108 was basically a good weapon, its 30mm ammunition was unique to itself and this led after WWII to a supply problem. By 1949, the Czechoslovak arms industry was making a wide range of ammunitions, including shells for ex-German weapons from WWII, new Soviet guns being supplied by the USSR, and of course Czechoslovak guns. At some point, the country simply had to limit the number of different ammunition types in production, and the MK 108 shell seemed like an expendable item. In the consequence of this decision, Czech S-92s soon received four 20 mm Berezin B-20 cannons instead of the original MK 108s. While the B-20 was lighter weapon with a lower weight of fire, it offered the benefits of higher range, accuracy and rate of fire. Due to the B-20's compact size and different placement, the ammunition supply for each cannon was raised to 200 rounds (versus the former 100 or 80 30 mm rounds). The modified machines received an "A" suffix. When many of the Czech S-92s were exported to Israeli, they were delivered without guns, since the IDF wanted to mount different weapons, anyway. In order to achieve a high communality between the various IDF combat aircraft types, the Israeli S-92s were all converted to British Hispano Mk V 20mm cannons, outwardly recognizable through longer barrels that protruded visibly from the aircraft nose. The ammunition supply of 200 RPG was retained.

Only eighteen (fourteen single-seaters and four two-seaters) S-92s were ever built. The main reason for the short production run was that they all were essentially being handmade, and Avia viewed the project as an annoying distraction from the company's production license for the Soviet Yak-23 "Flora" jet fighter, which began building in Czechoslovakia in 1949. Avia was also eager to demonstrate readiness for a license to build MiG-15s (at the time, possibly the best fighter in the world) and they reasoned that hand-assembling old Luftwaffe designs would not impress the Soviets.

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

With only a small number of aircraft in existence, the total number of Czech Me 262 re-builds for Israel was low, too: six S-92s were delivered until 1951 (three of them former Czechoslovak air force machines, the fighters had been phased out by late 1950), plus three newly built NS-92s and two CS-92 trainers from air force surplus stock.
Nevertheless, the S-92s' appearance in the Levant region created a lot of buzz, which was most probably also fueled by intentional British "leaks" to Egyptian intelligence in order to distract Israel's nervous neighbors from the procurement of a more modern and reliable fighter from Great Britain, the Gloster Meteor. The IDF "officially" began receiving Meteor F.8 jet fighters in 1953, but, reportedly, had been flying at least one or two earlier-version Meteors since 1950, which might have (on purpose) been confused with S-92s, since both aircraft shared a similar layout. However, the Meteor's presence would have of course aggravated the Egyptians who were paying top-dollar for their British-made Vampire jet fighters in a bid to one-up the Israelis, and the S-92s and their uncertain number to outsiders were a welcome distraction. Therefore, it's possible that the jet which crashed in 1950 was actually a Meteor and the British allowed the Egyptians to run with their S-92 theory. It is also possible that the crash never happened at all and the Me 262 story simply was a PR stunt!

Despite their weaknesses, the IDF S-92s frequently took part in military campaigns and fired in anger. Most of the time they took actively part in some of Israel's reprisal operations (Hebrew: פעולות התגמול, Pe'ulot HaTagmul) in the early 1950s, carried out in response to frequent fedayeen attacks, in which armed Arab militants infiltrated Israel from Syria, Egypt and Jordan to carry out attacks on Israeli civilians and soldiers. The last S-92 deployments took place in 1955, during a backlash operation against an Egyptian military camp near Gaza, which culminated in September 1955 when Egypt tightened its blockade of the Straits of Tiran, closed the air space over the Gulf of Aqaba to Israeli aircraft and initiated fedayeen attacks against the Israeli population across the Lebanese and Jordanian borders.
At that time the IDF S-92s might have been good for some more years of duty, but the lack of replacement engines and spares put a natural end to the type, so that the small fleet was retired and soon scrapped.

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

General characteristics:
Crew: 2
Length: 11.37 m (37 ft 3 in)
Wingspan: 12.60 m (41 ft 6 in)
Height: 3.50 m (11 ft 6 in)
Wing area: 21.7 m² (234 ft²)
Empty weight: 3,795 kg (8,366 lb)
Loaded weight: 6,473 kg (14,272 lb)
Max. takeoff weight: 7,130 kg (15,720 lb)
Aspect ratio: 7.32

Powerplant:
2× Avia M-04 (Junkers Jumo 004 B-1) turbojets, 8.8 kN (1,980 lbf) each

Performance:
Maximum speed: 840 km/h (521 mph)
Range: 1,050 km (652 mi)
Service ceiling: 11,450 m (37,565 ft)
Rate of climb: 20 m/s (3,900 ft/min) at max weight of 7,130 kg
Thrust/weight: 0.28

Armament:
4× 20 mm Hispano Mk V cannon with 200 RPG
2× underfuselage hardpoints for a 250 kg (550 lb) bomb or a 300l drop tank each

The kit and its assembly:
This build was spawned by a friend's idea who thought about Israel not only having procured the Bf 109 derivative Avia (C)S-199 in the late Forties, but also the Czechoslovakian S-92 clone of the Me 262. While the idea was unlikely, I spun it further and even considered a night fighter version for the IDF (somewhat as a counterpart to an Egyptian Mosquito night fighter with radial engines, which I had built some years ago). This became the conceptual basis for this relatively simple build.

The kit is the venerable but IMHO still decent Heller Me 262 B-1a/U1 night fighter kit – a simple offering with raised surface details, but a nice cockpit interior (for its time). The only real weak points are IHMO the wheels, which lack detail, and the somewhat robust antennae.

The model was basically built OOB, the only change is the rhinoplasty because I did not find the idea of using the original/outdated FuG 218 with its draggy antler array after the war convincing. As an alternative and inspired by the real world FuG 240 installations that actually entered German night fighter service on board of some Ju 88Gs, I sculpted a completely new nose section from spare parts, primarily a leftover nose section from a Matchbox Meteor NF.11 night fighter and some putty.

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) - WiP by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) - WiP by dizzyfugu, on Flickr

The big Meteor radome necessitated the guns to be re-located, included hollow steel needles for the gun barrels. The "cheeks" of the Me 262's triangular fuselage were a welcome, natural fairing for them – and there even was a real world Me 262 recce version that had a pair of guns re-located into a similar low position. The original 300 l drop tanks and their respective "viking ship" pylons under the forward fuselage were retained.
Since the new nose was fully devoid of surface details and the Heller kit came with raised details, I experimentally tried to create fake panel line with white glue, "painted" against a single stripe of masking tape, so that only one hard edge (facing forward) was created. The result of this improvisation did not turn out bad at all!

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) - WiP by dizzyfugu, on Flickr

Painting and markings:
Again a rather conservative choice – and finally a good opportunity to apply the paint scheme that IDF Meteor night fighters wore in the Fifties: the brown/blue standard camouflage on the upper surfaces, but uniform dark grey undersides without roundels.

The authentic upper colors for this scheme are RAL 5008 (Blaugrau) and RAL 8000 (Grüngrau), for which I used a 1:1 mix of Humbrol 77 and 79 (77 alone comes close, but is simply too bluish/greenish) and Testors 1702 (Field Drab, FS 30118; this color comes very close to the RAL tone and is just a bit darker). About the dark grey for the underside I am uncertain, but IMHO RAL 7021 (Schwarzgrau, actually the German early WWII Panzergrau) is the most likely color, so I used Testors 2094.

The upper surfaces were, after a black ink wash, heavily sun-bleached through post-shading with considerably lighter mixes of the basic tones. Due to the kit's raised panel lines and surface details, these were emphasized through light dry-brushing with light grey and silver. The black panels around the gun muzzles emphasize the contrast between the rather murky upper colors and the dark grey underside (created with decal sheet material).

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) - WiP by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) - WiP by dizzyfugu, on Flickr

The cockpit interior was painted with Revell 9 (Tar Black), as well as the landing gear wells. The landing gear struts were painted with Humbrol 240 (RLM 02), which was also used for a replacement starboard engine, since a very similar tone was the original overall color of the S-92s in Czech service. On the portside engine, the intake section was painted in aluminum, also simulating a replacement part.
In order to emphasize the radome's material, fiber glass, the nose was painted in a sand brown tone and then heavily bleached/treated with streaky, dry-brushed lighter tones, simulation the semi-translucent material as well as wear/tear and general material deterioration under harsh desert sun. It stands out well from the dark aircraft, but a black radome did not appear plausible to me, IMHO a black nose would have reminded too much of the Meteor night fighter?

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) - WiP by dizzyfugu, on Flickr

Markings were kept minimal, just IDF roundels on the flanks and on the wings' upper surfaces, plus the tactical codes and small, red squadron badges (which is not authentic, though) on the fin. The only individual addition are two kill markings under the cockpit's port side. The red walkway markings on the inner wings were created with generic decal strips.
Some more weathering was done around the gun ports, leading edges and the cockpit opening, and finally the model was sealed with matt acrylic varnish (Italeri).

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

1:72 Avia NS-92A, aircraft "42" of the חֵיל הָאֲוִיר (Kheil Ha'Avir, Israeli Air Force) 119 tajeset; Tel Nov, August 1955 (Whif/modified Heller kit) by dizzyfugu, on Flickr

A relatively quick build, thanks to the simple kit basis and only some rhinoplasty. The Meteor radome might be a little too large for the aircraft and for what there is supposed to be hidden inside, but the overall result looks pretty plausible, though. It's weird, but the radome as well as the as the Israeli markings do not look too fantastic?

PR19_Kit · August 13, 2019, 01:05:58 AM

I thought that radome looked familiar.

Not the prettiest aircraft you've ever built Thomas, but very nicely done and VERY plausible too.

Scotaidh · August 13, 2019, 01:49:50 AM

Very nice! Well up to your usual standard.

Don't be surprized if this turns up to be another 'real' discovery by someone!

Dizzyfugu · August 13, 2019, 01:50:54 AM

Nah, it was never intended to be pretty - the radome turned out to be a little big, though, I rather envisioned a nose similar to the F-94A/B, but sometimes you just have to take what you have in the donor bank... And it does not look bad at all.

TallEng · August 13, 2019, 03:51:04 AM

Quote from: Dizzyfugu on August 13, 2019, 01:50:54 AM
Nah, it was never intended to be pretty - the radome turned out to be a little big, though, I rather envisioned a nose similar to the F-94A/B, but sometimes you just have to take what you have in the donor bank... And it does not look bad at all.

I like it

Like you I too built a Me262 nightfighter with a more modern radome instead of the Antler type, I also started with a Meteor nose radome
and found it too big. I think i cut it into quarters and cut bits out to reduce the diameter somewhat. It should be on here somewhere, but
I'll be blowed if i can find it

Regards
Keith

TomZ · August 13, 2019, 04:26:57 AM

Ouch, that looks ugly!

Good one!

TomZ

NARSES2 · August 13, 2019, 06:13:14 AM

That does look good

Dizzyfugu · August 13, 2019, 06:55:39 AM

Quote from: TomZ on August 13, 2019, 04:26:57 AM
Ouch, that looks ugly!

Good one!

TomZ

Yes, there's something phallic about it...

Glenn Gilbertson · August 13, 2019, 09:41:34 AM

Great idea splendidly modelled!

nighthunter · August 13, 2019, 02:26:40 PM

Nice!

TheChronicOne · August 13, 2019, 02:28:57 PM

Glorious!!!!!

Dizzyfugu · August 13, 2019, 11:55:31 PM

Thanks a lot!

AndrewF · August 14, 2019, 01:28:11 AM

Great work, both on the model and the photography. Very convincing.

Old Wombat · August 14, 2019, 04:35:18 AM

Phallic?

Nah!

Great build, Dizz!

Dizzyfugu · August 14, 2019, 04:43:12 AM

Quote from: TheChronicOne on August 13, 2019, 02:28:57 PM
Glorious!!!!!

Thanks a lot for the Whiffie nomination! That came unexpected!