P-39N Airacobra ***FINISHED***

[PeterB]

Hi,

 

I am thinking of doing one of these.

Spot the difference! As with their Ju-87 D/G, Hobbyboss have produced two boxings with what I suspect is exactly the same plastic. They claim the Ju-87D is a D-3, but it has the long wing and cannon of the D-5, together with the 37mm cannon of the G on the sprues. Here they say they have boxed a P-39N and a P-39Q but as the boxart shows both have the twin 30cal wing guns and the 50cal gondola mounted ones! There were also a number of minor differences between the 2 models, depending on which batch they were from, for example different propellors I believe, but I will have to do a bit more research. There is also a little uncertainty with the colouring of the Russian ones. Most if not all retained the OD paint on top that they were delivered with, but if the Osprey Aces illustrations are correct many of them had the undersides repainted in a Russian Blue. Then of course the Russians modified the armament, seldom if ever using the wing 50cal on the Q, and also removing or replacing the wing guns on the N I think. As I said - more research needed but if I do have time to do one of these it will probably be the N. Both are currently on sale at £6.99 with Hannants and I suspect that they were somewhat less when I bought them getting on for 10 years ago.

 

And yes, I know Enzo would say do both - we will see. The P-39 is one of those strange planes where opinions differ considerably as to its worth, which gives me an excuse to bore you with a bit of background (as if I ever need an excuse)😆!

 

Cheers

 

Pete

[AdrianMF]

I’d say give us both and as much info as possible!

[PeterB]

Ok, I have decided to build the P-39N initially so here is the plastic.

As you can see I made a start on painting it when I bought it , but later research shows I am going to have to change the  blue to Neutral Gray - the profiles in the Osprey books do look bluish on the Russian planes but then they are the same on the US ones and the text says they did not repaint them after delivery. The interior green may have to change as well as I believe Bell used different colours - I will be relying on the info provided in an article by Dana Bell that is available on the IPMS Stockholm website which shows at the very least a mixture of chromate yellow, medium green and OD in the wheel wells, and on the legs. I rather fancy 29033 White 01 as shown on the box art as it has an interesting history, of which more later. Incidentally I have just remembered why I never built these kits - not for the first time HB have screwed up the prop, which is far too small so a bit of work is going to be needed to sort that.

 

Back in 1965 Airfix produced their P-39Q Airacobra kit which I bought as soon as I saw it, but back then I knew very little about the aircraft itself. I did know that the Americans produced a lot of them, but that the RAF had rejected it as it was considered unsuitable for use in Europe. I also knew that the US used them in the Pacific and that in the small paperback book I had on Saburo Sakai (Martin Caidin - "Samurai") the Japanese considered the Airacobra to be an easy target. As a result most of them were shipped to the Russians who seemed to like them, particularly low down for strafing. So here is a very compressed bit of background based on Detail and Scale, and also the Mushroom book.

 

The Bell P-39 had a number of unusual features for its time. The designer Robert Woods wanted to mount a large 37mm Oldsmobile cannon in the front of the plane so he went for an inline engine mounted at the centre of gravity behind the cockpit. This meant that the aircraft could be unusually streamlined with the engine in the widest part of the fuselage, and he also fitted a turbo supercharged 1150HP Allison engine which gave phenomenal performance when it first flew in April 1939 – speeds of almost 400mph, rapid climb, and high manoeuvrability due to the weight distribution – not bad for an underfunded company only founded about 4 years earlier. It also had a nosewheel undercarriage, and a form of "all round vision" canopy accessed through "car doors". None of these features were new but the combination of all of them in one design was probably a first. Unfortunately, things went downhill from there as the USAAC decided to “improve the plane” by getting NACA to make it “more streamlined” - they decided the supercharger intakes had to go, shortened the wing by 2ft, lowered the cockpit and lengthened the fuselage by 1ft. It might have reduced drag but it meant that a lower powered engine with only a single stage supercharger had to be fitted. At a stroke they significantly reduced the speed at altitude together with  the rate of climb and upset the balance making the plane harder to handle and prone to going into a flat spin. The USAAC was not bothered as they wanted a fighter which was fast at lower altitudes but it did seriously effect the aircraft's usefulness later on.

 

Both Wood and his boss Larry Bell were not happy with the changes but did not feel they could object as they needed a contract, being in the verge of bankruptcy at the time. Performance suffered further when about a ton of extra equipment such as self sealing tanks and armour were added though in fairness they were needed. The USAAC ordered 1000 P-39C/D, and both France and the UK also placed large orders, though only the latter received any, and they only equipped one Squadron for a short time as the performance was nothing like what they had expected based on the lighter and more powerful prototype. In addition they were unhappy with the armament. They replaced the single 37mm cannon (by now a Colt product) firing through the spinner, which only had 30 rounds and was prone to jamming with a Hispano 20mm with double the number of rounds, but were not impressed with the stopping power of 2x50cal mounted on the top of the nose together with 4x .303 mg mounted in the wings (which seems a little strange as the Spit Mk V only had 2x20mm and 4x.303), and noted that when the guns were fired it messed up the compass and filled the cockpit with fumes. They were soon withdrawn and many of them sent to Russia.

 

Not all of the British order was delivered however, as the Americans took over the last 200 for their own use after Pearl Harbor, calling them P-400. These could be distinguished by the longer 20mm cannon and most also had 12 exhaust stubs on each side instead of 6 on the P-39C/D, They served both in the Far East and in North Africa but were completely outclassed at anything other than low level. The P-39C was essentially the revised YP-39 after the Air Force finished “streamlining it” and never entered service as it was not combat ready, so the order was switched to the P-39D after 20 aircraft had been produced. This had the armour and self sealing tanks added and was similar initially to the RAF's Airacobra Mk I but with 4x30cal wing guns. The D1 had the 37mm cannon replaced with a 20mm one as in the P-400, though the D-2 reverted to the 37mm cannon. The P-39E was not built and the P-39F had 12 stack exhausts and a different prop but was essentially a P-39D. So far the changes were minor and the production batches small, and this pattern continued with the H, J, K, L and M versions which had different engines and props plus numerous other small changes – the G was not built.

 

More later on the main production versions. the N and Q.

 

Cheers

 

Pete

 

Edited June 4, 2021 by PeterB

[Alex Gordon]

It's always an education following one of your builds Pete,looking good so far.I finished one last year,I had to be very inventive putting in the noseweight,shaping it around the propellor insert and lining the noseleg bay in the process.Enjoy,they are fun kits and go together well.

[PeterB]

Hi Alex,

 

Yes, although the instruction sheet has an explanatory list of symbols including one for "weight" , it has not been used one the build details but I am pretty sure it is going to need some! However, as I mentioned earlier the kit prop is no use - 29033 was one of the first batch of P-39N-BE, but not one of the first 166 built and so I should have an Aeroproducts prop of 11ft 7inches diameter (the first 166 had one of 10ft 4inches diameter apparently). The kit offering scales out at a totally inadequate 9ft 6inches ie a whopping 4mm short on each blade!

The circle is the correct size. I have found a prop in my spares box from I believe a Frog B-25 which has the right sort of shape and direction of rotation and is 12ft 6inches diameter so I will modify that and replace the kit one. That means I will not be using the "sleeve" insert and metal "axle" so should have room for some lead, though it will still be a tight fit I expect. Fortunately I have 2 thicknesses of window lead strip, one of which is very thin, so I can squeeze that into some fairly tight places. I will be covering the props in more detail later but AFAIK none of them had one as small as the one HB provide - I seem to recall that props are not one of their strongest points - the rear one on their Dornier 335 was a mess with 2 blades angled the wrong way and the third was correct I think - total lack of attention by somebody! Also the one on their P-40C, or was it their Spit V was a bit wrong as well. Still I must be wrong as it is an "Authentic Kit" or so it says on the box - not impressed! Reviews/builds of some of their more recent kits suggest they are pretty good now, but they still seem to drop the odd clanger - then they are not alone in that and at least they are cheaper than some of the other "botched" kits I have bought.

 

Cheers

 

Pete

 

 

[PeterB]

Main assembly about complete. The various pins and sockets don't leave a lot of space for ballast but I have squeezed some in and it will be close - I may have to put a little more in space at the front where the prop shaft goes, but that should be easy enough.

Some filler will be needed but not a lot. On the box it says "Easy assembly authentic kit". As to the former, I would say "Yes and No". The various pins and sockets all needed easing as did the joint between fuselage and wing as they were just too tight. To make matters worse, unlike most of the HB kits I have built this one does not have a solid cockpit, but comes with a floor unit with the IP and stick built in and a seat to add. Fair enough but you also have to add the nose wheel assembly before fitting it into the fuselage section, and then fit the wing and lower fuselage over it which is a real fiddle, but I got there in the end. In terms of "authentic" then if they mean accurate then I would have to give the same answer. Dimensionally it is good, unlike the old Airfix P-39Q kit I had in my stash, which was too small as I found out when I bought this kit - it went in the bin and I bought the HB P-39Q as well. I have already mentioned the problem with the propellor - I seem to remember the Airfix kit was better but still small, possibly they thought it had the 10' 4" version. Both options for the N are Russian so they should also have provided the D/F loop (RPK-10?) that they fitted under the fuselage. Still, I have a spare from their Bf 109G-2/Trop kit I am building in the 109 STGB so no problem. There are a couple of odd things about the sprue - they include two pairs of wing guns complete with a bit of the leading edge but the guns are already moulded on the wing sections (I have cut mine off), so why? Also they include what seems to be the aerial mast that went on the spine behind the cockpit (but only on some planes and not usually on the Russian ones), but there is no hole for it and no mention of it in the instructions - they seem to have been a little confused when they designed this kit!

 

Ok, more history.

As I mentioned earlier initial production runs were quite small – 20 P39-C, 454 D, 336 D1,158 D2 and 229 F, with a further 25 J which had an automatic supercharger control I believe. However 1800 were ordered as model G/H, but in fact none were produced under that designation. Instead 210 were K, 250 L, 240 M, and the balance was produced as the P-39N together with an added batch bringing the total production of that model to 2095 in 3 batches. All the planes of the N series had an Allison V1710-85 (E19) engine of 1200HP with a modified reduction gear, and the first 166 had an Aeroproducts prop of 10' 4” diameter, the rest having an Aeroproducts prop of 11' 7” diameter. 4 fuel cells were removed to reduce weight. After 500 N had been built, production switched to the N1 of which 900 were made – this had a few minor changes and a change to the position of the Centre of Gravity which had become very touchy when the fuselage guns and cannon had fired off all their amunition apparently. The final 695 were N5 which had the armour behind the pilot reduced from 231lb to 193 lb, a different radio and modified oxygen system. I will cover the Q model if I build it but for the record 4905 were built bringing the total production of P-39 to 9558 according to my sources.

 

So, moving on to the Airacobra in Soviet use, first of all it seems to be true that the Russians did like them and that most of their combat took place at fairly low level where the P-39 had a reasonable performance. However, contrary to the impression given by numerous sources in my youth, it would seem that they did not use them very much for ground strafing as they had plenty of Il-2 Shturmoviks for that specific purpose and they were protected by a lot more armour. As to the armament, they liked the cannon, particularly the 37mm one, even though it was slow firing and only had about 30 rounds, and the 2 x.50cal mg in the nose were considered acceptable too. They were less impressed with the 4 x.30cal in the wings of all models up to an including the N, as they were too light to do much damage and I believe they also had problems with getting the correct ammunition, so they usually removed them, thus saving weight. With the arrival of the Q model the wing guns were replaced by 2x 50cal in underwing gondolas, but again there seems to be no evidence that the Russians used them. Of course Soviet designed fighter aircraft rarely had wing guns, relying on an engine mounted cannon and a couple of mg on top of the nose in for example the Lagg-3, and 2 or even 3 nose mounted cannon in later designs. I have already mentioned the D/F loop they fitted, but they also added quite a bit of strengthening to the structure as they found that it was weak in places, like around the radio access hatch - Bell did the same with some of the P-39Q models they built. One thing they did not like too much was the car doors - although they could be jettisoned to bail out, many pilots were either killed or injured by hitting the tailplane. On the plus side the low wing and clean undersurface made it relatively safe to belly-land.

 

Cheers

 

Pete

Edited June 5, 2021 by PeterB

[PeterB]

I am still debating whether or not to build the P-39Q. HB provide decs for two versions, one Russian so it will be identical to the N, and the other a US flown one in 1944, but their research has let them down again as it is one of the P-39Q-6-BE recce versions flown by 71TRS. At the very least that means it needs a small blister under the fuselage just behind the wing with a couple of cameras, and pics of this group in New Guinea show a field conversion to mount another oblique camera in the Port side radio hatch either as well as or instead of the belly ones. All easy enough to do, but if I am going to have to fart about with it I might do something a bit more radical – I have always fancied an Airacobra 1/1A/P-400! As far as I can tell it just needs a bit of brass tube to make a 20mm cannon in the spinner, 12 stack exhausts which are now available AM for under £3, and a 10' 5” diameter Curtiss Electric prop. It would give me the choice of one of the few RAF machines, one of the same in Russian service, or US ones in either Australia, New Guinea , Guadalcanal, or maybe the Western Desert - not entirely sure about that - with a wide range of colour schemes. It won't be totally accurate - the nose wheel will not quite be right for a start, but then none of my builds never are - I am tempted!

 

It will still work out below a tenner even with the aftermarket exhausts as everything else will be from the spares box/decal stash. Any suggestions will be welcome!

 

Pete

Edited June 5, 2021 by PeterB

[PeterB]

I have fettled the prop.

OK, all the previous models of P-39 and the first few P-39N had a prop with 6" (2mm) shorter blades, but even those would still have been noticeably bigger than the kit one. I may need to slim them down a little and thin the leading and trailing edges as they are a bit thick, but this is what it looks like tacked on the plane.

I mentioned earlier that the kit has a seperate cockpit floor/nose bay roof which has to be glued in the upper fuselage and was a bit of a fiddle. When I put the main undercarriage on I realised I might have mounted the "roof" too high at the front - the fit being somewhat vague. When I put the prop on it confirmed my suspicions as there was no clearance, so I managed to push the nose wheel and roof down a bit, which makes things look rather better. Don't know if I got it in the wrong place or if HB were working on the basis of their dodgy propellor!

 

The nose is packed with lead and it just (and I mean only just) sits tail up - contrary to the instructions it needs every available space used for ballast as I don't think the plastic sleeve and metal rod "axle" provided in the kit would be enough on their own!

 

You might just be able to see the blob of filler I have fitted and shaped under the rear fuselage as the base for the D/F loop the Russians added to their P-39N and Q, and maybe some of the earlier versions as well. I am not fitting the centreline drop tank so all that is left is the canopy and exhausts.

 

So here is the penultimate part of the background-

 

As to paintwork, they tended to leave them in whatever colours they were delivered in, at least until they had a major overhaul, when some may well have been repainted in contemporary Russian colours. The ex-RAF ones were Dark Green and Ocean Grey over Medium Sea Grey, and the ones received direct from the US were in OD over Medium Gray with US stars in the usual 4 places initially, so these were usually overpainted with a red star and a further 2 added – this is why 4 of the ones on the kit should have a blue circular background and 2 not, but although shown on the box art HB have provided just 6 red stars for this one so I will borrow the spares from the “Q” which do have a blue background. In other cases the blue was overpainted in a Russian green colour. The one I am building certainly entered Russian service in September 1943, maybe earlier, and I am doing it as in May 1945, and I doubt it was repainted, so rightly or wrongly I will paint it in Xtracolour "Faded OD". At some point the manufacturer started painting red stars on, so the blue backgrounds were no longer there, but apparently these so called “transit markings” from 1944 onwards appear to have been painted on a white circle, Again this was usually overpainted in green on arrival but not always, and the original Airfix P-39Q kit had the red stars on a white circle, though in later boxings the background was changed to green, and the second option provided by HB for their N has also white circles but curiously they say that it had been repainted in Soviet green/blue so logically the white circles should not be there! The Guards units painted the spinners in colours that indicated their unit – red, blue, yellow, white and so on - mine will be blue.

 

Cheers

 

Pete

Edited June 6, 2021 by PeterB

[PeterB]

A little more touching up to do but it is physically complete.

Then it will be on with the decs which could be fun on the basis of previous HB kits - they stuck like limpets and were a pain to slide into place without breaking! Speaking of decs there are 9 on the sheet which HB make no mention of whatsoever - 3 of them are to go on the prop, the rest is a mystery.

 

Finally we come to the slogans which are so apparent on a lot of photos and profiles. These can be loosely split into 3 groups. Patriotic – eg “For Stalin”, “For Russia”, “Death to the Invaders” etc. Personal – “in memory of my fallen brothers”, “For such and such a fallen pilot” etc. Lastly what in the West would be called “presentation markings”, for example “For the workers of such and such a factory”. Of course all the planes were given to Russia under lend lease terms so they were not true “presentations” but I guess they were used for morale purposes. The plane I am building using HB decs (if they work) has examples of the last 2 types of slogan. It was issued in September 1943 to the ace Captain Ivan Il'ich Babak of 100 GIAP (Guards Fighter Aviation Regiment) and he flew it until promoted to lead 16 GIAP in February 1945. It carries a “presentation” slogan on the fuselage to the rear of the cockpit which apparently reads “For the schoolchildren of Mariupol”. He personalised it with a large white winged angel with sword and trumpet on the starboard nose. When he was transferred the plane went to fellow ace Grigori Dol'nikov who initially left it as it was but he had the Angel painted out in Soviet Green, and when another pilot called Pyotr Guchyok was killed on April 18th he had a slogan “For Pyotr Guchyok” painted over the patch. Four days later Babak was also shot down and believed killed, though in fact he was a prisoner, so another slogan appeared on the Port side of the nose “For Vanya Babak”. HB have provided decs for it as it was just before the war ended.

 

Pete

Edited June 7, 2021 by PeterB

[PeterB]

Oh Dear - Hobby Boss strike again!

 

I have got some of the decs on and they are working well so far. As with previous HB kits some of them are numbered incorrectly but I can cope with that. However, there is one big mistake. This is the Port side.

The dedication to the school is behind the cockpit and the "For Vanya Babak is horizontally aligned on the nose - so far so good, but this is the Starboard side-

The dedication is correctly angled across the patch where Babak's personal insignia has been painted out( I used Colourcoats AMT-4 Green) , but when I slid it off the backing I realised that it was another "For Babak" instead of " For Pyotr Guchyok"! Somebody at HB has seen the writing angled up on the nose and has assumed it was the same inscription on both sides. Oh, well - it will have to do. I know Trumpeter are supposed to make the plastic for most if not all HB kits in Macao but what nationality are HB  - Chinese presumably so maybe their knowledge of Russian is no better than mine.

 

Cheers

 

Pete

Edited June 7, 2021 by PeterB

[PeterB]

Well that did not take long.

Just needs a coat of flat varnish and I will get it in the gallery. Waiting for some bits to arrive before I decide what the next one will be. Could be a Q as HB intended but I still rather fancy a P-400!

 

Cheers

 

Pete

[Alex Gordon]

She's looking very good old fruit,finding places for the noseweight is an exercise in ingenuity.Something that Hobbyboss do quite frequently if they don't know is mirror the colour scheme from one side to the other

 

 

 

 

To the casual builder I suppose it's not an issue,to someone more serious the benefits of a photo are readily apparent.

 

 

[PeterB]

Not quite mirror as the Port slogan is horizontal and the Starboard is diagonal which they got right, but the lettering should be rather different and of course they missed the green patch over the previous badge!

Looks like there should be a radio or something under the rear canopy which I did not spot.

 

Oh well, it's done now.

 

Pete

Edited June 8, 2021 by PeterB

[AdrianMF]

Well we are ready for our end of term exam on the Airacobra now! It looks very nice, even though it fought back a bit. And the kit is certainly better than the old Airfix attempt.

 

Regards,

Adrian

[PeterB]

Well, that is done so I will get some pics in the gallery before too long.

 

I have started another build thread for the next one as it will not be entirely OOB, not that this one was exactly either as I had to make a new prop..

 

Cheers

 

Pete

[PlaStix]

Hi Pete.......welcome to the GB.............greaat to have you here............and before I know it.............you're finished!! Wow!! Very impressive project! Very well done.

I am sorry I did'd get to your thread before you had finished and thank you very much for building it in this GB>

Kind regards,

Stix