TEMPORARY NOTICE: I’ve noticed today (16 September ’10) that EADS have apparently redesigned their Company History webpages and removed some of the photos I’ve linked to in this post (which now show up blank). I will try to and dig up where have they been moved to, but it may take awhile…
NOTICE NO.2: Due to my two-year-long failure to finally address the above (it really did take awhile as it turns out :D ) – and the new friendlier visual format of this blog – I’ve decided to outright rewrite and refresh the entire post, adding a bit of new information and photos, and correcting the odd mistake. This new & improved version – posted as of 21 September ’12 – can be seen here :).
When the first Bf.109s faced their German rivals in mock dogfights in the mid-30s, few observers – in any country – were left in any doubt about the potential of Messerschmitt’s first complete fighter design. International flying competitions in the years preceding WW2 had further underlined these impressions, while an all-up production run of almost 35,000 examples, spanning more than a decade in one form or another, and an impressive – though in the later stages of the war a bit diluted – combat record removed any doubt remaining.
A very advanced design by contemporary standards, the Bf.109 was not really ground-breaking per se; when all was said and done, it had not really introduced anything completely new into the rapidly advancing world of interwar aviation. What it had done however was combine all the cutting-edge technologies of the time into one airframe – the monoplane configuration with high wing loading; the powerful liquid-cooled V engine and its variable-pitch prop; retractable gear; the enclosed cockpit…
Two more of its immediately apparent trademark features were the automatic leading edge slats and – for a combat aircraft – very low weight, courtesy of a clever design philosophy that made the aircraft simple and cheap to build and quick & easy to service and maintain – not to mention making it tough, durable and reliable out in the real world. And while the big engines and retractable gear could easily be traced to some of the eminent combat aircraft of the time, these two were inherited from a far more unfighterish source – the Bf.108 tourer…
1. When I grow up I want to be a fighter!
The aircraft that would (among other things) lend most of its technical solutions and complete tail unit to the early Bf.109 started out in life as the four-seat* M.37 tourer of 1934. Designed by the young Willy Messerschmitt, Bayerische Flugzeugwerke‘s chief designer, the M.37 was intended to compete in the 4th Challenge de Tourisme Internationale being held that same year. This interesting general aviation competition – wish they held something like this today! – included categories such as “Short Takeoff”, “Short Landing”, “Fuel Consumption”, “Minimum Speed”, “Maximum Speed” and “Technical Trial”, as well as a 9500 km race across Europe and Northern Africa (that had also stopped in Zagreb! :D).
*though intended as a four-seater, the M.37s and the early 108s were operated as two-seaters, with the rear seats permanently removed to provide some storage space (with virtually all pre-Bf.108B versions having been used for races and flying competitions), giving the impression that they were outright designed for just two
Based partly on Messerschmitt’s previous M.29 – designed in a similar vein for the 1933 competition, but never taking part due to a spate of crashes – and the M.35 aerobatic trainer prototype, the M.37 was a sleek low-wing stressed-skin all metal monoplane with retractable gear, an enclosed cockpit, full-length flaps with roll control provided by roll spoilers (!) and a variable-pitch prop – just enough to make it that less inconspicuous among the wood and fabric biplane crowd :). The unorthodoxy continued under the skin as well: the wing was made around only one spar, a design that was made to work by Messerschmitt’s extensive glider building experience gained in the Versailles Treaty-limited post-WW1 period. The famous mechanical leading edge slats could be manually extended to greatly improve the airflow over the outer wing sections – which were likely to stall first – reducing the stall speed to just 61 km/h (33 kt). This in turn significantly shortened the take-off and landing rolls – not quite to STOL levels, but very close – and increased low-speed maneuverability and handling at high angles of attack.
As with the wing, the whole design philosophy was to make the aircraft as simple as possible, with the fewest realistic number of parts used to create a light and durable airframe. Functional minimalism. And it had worked – compared to other (later) metal aircraft of similar design, the M.37 was indeed among the lightest and best performing. Official flight testing prior to the competition was marked by the general enthusiasm of all the pilots that had flown it, prompting the German aviation ministry – the Reichsluftfahrtministerium, RLM – to give the aircraft a tentative green light as the Bf.108. Of note here is the oft-confused designation: “Bf” obviously stood for the initials of Bayerische Flugzeugwerke; however, when the company was renamed into Messerschmitt Flugzeugwerke in 1938, all subsequent designs were given the “Me” prefix. The designs that had been produced prior to the name change kept their old prefixes – so there never really was an “Me-108″ as can be found in some Internet sources.
However, despite all its qualities, one aspect of the aircraft raised doubts among some test pilots – the roll spoilers. With the full length of the trailing edge taken up by the flaps – increasing the wing area by a whopping 8% when extended – there was no space for any ailerons; roll control was then provided by spoilers on each wing that would create a difference in lift between the wings. For example, if you had wanted to turn left, the roll spoiler on the left wing would extend, disrupting the airflow over it and reducing lift. The right wing would now be producing more lift and sort of tip the aircraft around its center of gravity, causing the aircraft to roll to the left. This was fine in theory – and is used on a number of civil and military aircraft today – but back then it was eyed with suspicion and more than its fair share of antagonism. This came to a head when test pilot von Dungern was killed in a 108 while testing the spoilers, presumably somewhere near the edge of the envelope.
With the RLM’s well documented dislike of Messerschmitt threatening to ground the 108 – like it had the M.29 a year before – there was no other option but to revert to a conventional aileron arrangement. “Conventional” should be taken with a grain of salt though, because the resulting arrangement still managed to raise an equal number of eyebrows…
In this form the aircraft became known as the Bf.108A, the designation under which it would be entered in the competition. It’s beautiful handling and avantgarde features did not help its case there though, when the far lighter, nimbler and simpler wooden aircraft wiped the floor with it for most of the competition…
Yet, the Bf.108A did notch up several wins, all of which would steer its later development into the tourer we know today. The top three aircraft in the “Fuel Consumption” category for example were all 108s – with the winner notching up an impressive 10 kg (14 l)/100 km. This number, in many cases exceeded by today’s SUVs, was made even more impressive by the fact that the 108A was not powered by some microscopic fuel-sipping engine, but a 220 HP Hirth HM 8U inverted V8 (how’s that for a GA engine? :D). This had also helped in the “Maximum Speed” event, where the 108s again took the first three places, with the slowest – at 283 km/h – being 30 km/h faster than the next contender. The trans-Europe race was less of a success, with one 108A, flown by Theo Osterkamp, placing fifth – but the result was due more to external influences (weather and navigation) and the scoring system (points being based on the total average cruise speed, including stationary periods, which meant a weather delay for example would cause a decrease in the average) than the aircraft itself. Indeed, when everything fell into place, the 108s had regularly posted the highest flying average speeds – including the leg to and from Zagreb :).
In total, when the competition tally was done, the three 108s were ranked 5th, 6th and 10th (out of 19). But more importantly, their demonstrated low fuel consumption, high speed and beautiful handling – and comfy leather seats! – had lent them well to cross-country touring. A clean, aerodynamic airframe able to go fast on not much power – sounds very much like the Lancairs, Cirruses and Diamonds of today, doesn’t it? :)
This did not slip past the then cash-strapped BFW, where Messerschmitt had decided to capitalize on the type’s success by adapting it for series production. To this end, a batch of pre-production Bf.108B-0 models was made (though they were still commonly known as the Bf.108A) with each successive aircraft representing a slight move toward the production standard.
In 1935, these had also started making a name for themselves – quite literally. The fastest light tourer in the sky, it was chosen by famous German aviatrix Elly Beinhorn for her record-breaking flight from Berlin to Constantinopole (now Istanbul, Turkey) and back. Her little 108B-0 had more than lived up to its Taifun nickname, taking just 13 and a half hours to cover the 3,470 km trip, flying along at a respectable average groundspeed of 257 km/h (139 knots).
Success like this had opened the floodgates and the 108’s already considerable popularity skyrocketed (as much as it could have in the general aviation scene of the 30s). The full potential of the design had immediately become obvious at the BFW works, where Messerschmitt set about turning the 108B-0 into the definite four-seater, a true cross-country airplane. The result was the Bf.108B-1, now adopting Taifun as its official name :).
The idea behind this version was to make the aircraft more production- and consumer-friendly, so first to go was the A model’s powerplant. The expensive and hard-to-come-by VDM variable pitch propeller was replaced with a simpler and cheaper two-blade fixed pitch prop (though an Me P7 two-blade variable-pitch unit was offered as an option), while the HM 8U engine was swapped for the readily available 240 HP Argus Ar 10C inverted V8. The wing too was made a bit duller by the reversion to a fully conventional aileron/flap arrangement – though it had also gained a wing folding mechanism (at the root) for easier transport by road or rail. The slats were now made automatic, extending at a certain speed by air pressure. Additional minor changes included the removal of the upper tailplane bracing mentioned previously, the replacement of the next-to-useless tailskid with a tailwheel, and the shortening of the glazed canopy over the rear seats.
In this role and form, the 108B-1 had continued to participate in international competitions, rallies and fairs – most notably the 1936 Olympic Games held in Berlin – but this time under the increasingly ominous banner of Nazi propaganda. Indeed, even before WW2, the fast-growing Luftwaffe had been eying the 108 as a liaison and communications aircraft to replace the obsolete and lumbering biplanes then being used.
However, the 108’s biggest contribution to the Wermarcht’s war effort was as the basis – the parts donor if you will – for the amazing Bf.109. In a fascinating display of lateral thinking, in 1934 Messerschmitt simply took the plans for the 108A and modified them into a single-seater with a narrower fuselage, a big V12 up front – a Rolls-Royce Kestrel for the first prototype, proving that irony was alive and well back then – and some boom booms in the slightly modified wings. Apart from the changes needed to fit all of these together, the rest was all 108 :).
While the wildly differing roles of these two aircraft may have raised some doubts, the 108’s base design turned out to be just the thing for the new fighter. It’s simple construction meant the 109 was light and maneuverable – and we all know how that turned out in the early stages of the war – and it’s relatively low parts count meant it was simple to maintain and repair out in the field with facilities and tools at hand. Lacking complicated whizz-bang construction elements meant it was far more tolerant of combat damage and the chances of a disastrous “lucky” shot disabling the entire aircraft were greatly reduced. At the same time, the clean airframe did not want for performance, so the 109 could do with less power than a similar aircraft – quite a welcome feature given its notoriously short range.
2. Oh, the irony!
Having had the (mis)fortune of being the most advanced light aircraft in the world during a period of turbulent political changes, the 108B-1 had quickly accumulated its fair share of odd operators. Apart from the “usual” ones such as Bulgaria, China and Japan, there were a couple of… unexpected ones to say the least, including the Royal Yugoslav Air Force. The dozen or so examples bought in 1939 were part of a larger batch that had also included approximately 60 Bf.109Es and quantities of spare parts – all paid for not with actual money, but in strategic materials such as iron, aluminium, copper and coal, materials abundant in the lands of former Yugoslavia, but scarce and badly needed for the war buildup in Germany. While the 108s were to lead relatively uneventful lives in the training and communications roles, the 109s would enter the history books during the German invasion of 1941 as the only time Bf.109s would ever face Bf.109s in outright aerial combat :).
Next on the scale of improbable is the – the US military :D. While it wasn’t uncommon for the USAAF to fly and test captured Axis aircraft, the single Bf.108B-1 – bought by the US Military attaché to Berlin in 1939 – had never left Germany and was used as a high-speed staff transport. Designated the XC-44, this aircraft was flown all the way until 1941 when it was repossessed by the German government following the US’ formal declaration of war on the Axis powers following Pearl Harbor.
But by far the most interesting 108s were the Messerschmitt Aldons, the designation of four examples impounded by the RAF at the beginning of WW2. Used in the communications role, the 108 had proved to be the fastest type for that purpose in the UK, though its close semblance to the Bf.109 was to cause some worrying “identification problems” among defending RAF fighters…
(and for those of you who think “How can the 108 possibly be mistaken for a 109?”: the first of the long-nose RR Griffon-engined Spitfires – the Mk XIIs – were delivered with clipped wingtips, intended to improve roll rate and increase speed at low altitudes, a feature well known and seen on a number of previous marks. On the ground, the Spitfire’s famous elliptic wing planform was still more than obvious in spite of the change. Up in the air however, on their first few sorties, only their new-found speed advantage kept them from being shot out of the sky by patrolling Hawker Typhoons which had mistaken them for attacking 109s… and these are Spitfires, well removed – on the ground – in shape, form and color from any version of the 109).
The post-war period too saw its share of odd 108 operators, including Czechoslovakia (where the type was known as the K-70), Poland and the Soviet Union, all of which had flown a few aircraft captured during the final days of WW2. For the full photo history of the 108’s civilian and military service around the world, you can visit these two excellent pages, a goldmine from which I’ve linked many of the above photos:
- Pictorial Overview of the Bf.108, Part 1 @ Aeronet Aviacion
- Pictorial Overview of the Bf.108, Part 2 @ Aeronet Aviacion
- Pictorial Overview of the Bf.108, Part 3 @ Aeronet Aviacion
3. Western promises:
Unlike its armed cousin, the 108 did not go through new versions like pairs of socks. Apart from the Bs, there was only one other major production version; and aside from that there were curiously few experimental models as well. But what they lacked in quantity they had certainly made up in quality…
By far and away the most normal of these was the C-1, an ungainly looking 1936 modification that had seen the standard B airframe fitted with a Siemens Sh 14A-4 7 cylinder radial, churning out just 160 HP. Combined with the radial’s large cross-section – which necessitates more power to overcome drag – and 80 HP (33%!) less power than the Argus engine, you can imagine why this was a one-of model…
At the other end of the spectrum was a never-built version that some sources also label as a C-1 (it could entirely be possible that the designation was re-used). Diametrically opposed to the Siemens model, this C-1 was to have been a high-speed version, fitted with a Hirth HM 512 inverted V12 that would have developed a whopping 400 HP on takeoff! :) Ground testing in 1938 had shown that the airframe started experiencing noticeable vibration above 325 km/h, which progressively became so severe that it had threatened to tear the airframe apart. Given the scope of engineering changes that would have been necessary to make this work, the project was quietly dropped…
That the only way was up – literally – was demonstrated in 1939 by a specially modified high-altitude 108B-1, built to capture the altitude record for its class. Fitted with a turbocharged Hirth HM 508 inverted V8 producing 270 HP (and also providing bleed to a pressurized cabin), it had reached an impressive 9,125 m (29,930 ft) of altitude in the hands of Hirth’s boss, Hermann Illg.
The series production models were less exciting however – and were suffering from an acute case of Cessna Skyhawk-itis as well :D. If you took 10 random Skyhawks of the same model and same production year and lined them up, I guarantee that you’d be able to find at least one unique feature or option on each of them… a double landing light here, the static port moved to there, an instrument layout just that little bit tweaked… The Bf.108 was no different, with options from one version sometimes being used on another, which made sorting them by model numbers a bit difficult – but after roving the Internet far and wide I think I managed to nail it (at least in general terms):
- B-1 – the already described base model
- B-2 – generally similar, but with the wing fold system removed and the variable pitch Me P7 prop fitted as standard. These versions could easily be recognized by the thinner metal prop blades connecting within the spinner hub
- D-1 – produced from 1941, this was the first model intended outright for military use and featured a modified vertical stabilizer, improved fuel feed system, a more powerful electric system, vertical speed indicator, windscreen wiper and a constant speed propeller (whose crowned spinner became the model’s distinctive outside feature) being turned by an As 10R engine of the same output as the C model. It should be noted here that “variable pitch” and “constant speed” propellers are not quite the same thing: a constant speed propeller will automatically regulate the pitch of the propeller blades to maintain the same RPM regardless of throttle setting. The variable pitch system however will only change the pitch to a preset setting (sort of like shifting up a gear in a car), with the RPM still regulated by the throttle
The D-1 would also be the last Bf.108 version produced in Germany before production was transferred to France at the beginning of 1942. In a bid to free up domestic production capacity for badly needed Bf.109s, the Bf.108B-2 and D-1 were allotted to the Société Nationale de Constructions Aéronautique du Nord, SNCAN, just outside Paris, where they would remain till the end of the war – with interesting consequences.
Following the liberation of France, SNCAN – having produced just 170 aircraft in two years, out of the original type’s total run of about 880 – was left with a significant number of uncompleted airframes and engines. Deciding it’d be a waste to throw them all away – and desperate to gain a foothold in the country’s recovering economy – the top brass at SNCAN had decided to restart production of the aircraft, but this time as the Nord Pingouin (what an insult – demoted from a typhoon to a cute polar animal :D). The base model, the Nord 1000, was virtually identical to the Bf.108B-2, using the same German engines and systems up till now standing around in the company’s warehouses.
Once these were exhausted, it was a relatively simple matter to remanufacture the aircraft from the original plans, the production tooling being already set up and waiting. However, the engines had proved to be a bigger problem, having been imported from Germany (where the Argus factory was leveled in the mean time). To get around this, SNCAN had decided for the easiest method – using a locally built engine of similar power. The only one available was the 233 HP Renault 6Q-11 6 cylinder inverted inline, giving the new Nord 1001 Pingouin I a significantly pointier nose than the Bf.108’s. A generally similar Nord 1002 Pingouin II – the most common variant – differed only in having a slightly more powerful (and right-turning) 240 HP 6Q-10 engine, bringing the power rating up to Bf.108 levels (not that the 7 HP mattered much). In total, 286 Pingouins were produced, bringing the overall 108 total to above 1,100 examples (unfortunately I could not find the year French production ended – but with the aircraft remaining in service till the early 60s, and their low production volume, I’d wager a guess that 1950 or thereabouts could be the year).
Note: some of the surviving aircraft had later been retrofitted with “normal” Lycoming and Continental piston engines and have a shorter, broader and more oval cowling. For the sake of simplicity, I decided to represent only the original Renault engine models here…
4. A (third) leg to stand on:
In the meantime, back during 1943, SNCAN – under guidance from Messerschmitt – was working on modifying the Bf.108B-2 with tricycle gear, which was coming into vogue at the time. The two prototypes converted as such were designated the Me-208 – in line with the designation issue mentioned previously – but only one had survived the war intact, to be renamed the Nord 1100 Noralpha. Like with the base 108, SNCAN had decided to finish the design and market it – having already done 90% of the work – with the result being the Renault 6Q-10-engined Nord 1101 (known as the Ramier in French Air Force service) whose production ran to the 205 example mark.
Like the 108, the Noralpha had a knack for testing out different engines :). Along with the planned, but never built, Renault 6Q-11-engined 1102 Noralpha II, the 1104 was a one-of model equipped with a Spanish Potez 6Dba engine of identical 6 cyl configuration and the same 240 HP as the 6Q-10.
But the ultimate expression of power – indeed of the entire 108 design – were the two 1959 Nord 1110s, re-engined with not a puny piston, but a 550 HP Turbomeca Astazou II turboshaft (lifted from a helicopter)! One of the two, registered F-AZNR, is still alive and flying today :).
5. Penguins and Typhoons live longer:
Today, it is estimated that there are 25-30 flying Bf.108s remaining worldwide (though I’m not sure whether that includes the Nords as well), a number being operated – naturally – in Germany, and by no less than Lufthansa’s and Messerschmitt’s “history flights” (the Deutsche Lufthansa Berlin Stiftung, www.dlbs.de, and Messerschmitt Stiftung respectively). Lufthansa’s example, D-EBEI – quite possibly the most famous 108 today – also proves that there is some humor left in today’s straight-face corporate world: for irony doesn’t quite cover a Bf.108 Taifun named Elly Beinhorn… :D
While virtually all survivors were retrofitted with modern constant-speed prop units, one great-looking B-1 model, D-EBFW, is still proudly sporting its fixed pitch prop :).
For more modern photos – there are some beautiful ones and it wouldn’t make sense to cram them all in here – you can visit these Airliners.net “galleries” I’ve linked below, sorted by type:
6. Bf.108 Specifications:
7. Version overview:
Reading through this prior to posting it, I’ve decided it’d be a prudent move to sum up all the Bf.108/Nord versions in one place, as trying to keep track of all of them was giving me a headache :). This is only a quick list with some distinguishing features, for reference:
- M.37 – the first prototypes, used for initial flight testing, equipped with roll spoilers
- Bf.108 – the designation adopted during tests, structural identical to the M.37
- Bf.108A – 1934 competition aircraft modified with ailerons
- Bf.108B-0 – pre-production versions
- Bf.108B-1 – the first production version, with folding wings, Argus Ar 10C and fixed pitch prop
- Bf.108B-2 – B-1 with the folding wings removed and the Me P7 variable-pitch prop fitted as standard
- Bf.108C-1 – the Siemens radial model and/or the proposed HM 502 V12 model
- Bf.108D-1 – final German production version fitted with a constant-speed prop, As 10R engine, more powerful electrics and miscellaneous small changes, produced mostly in France
- Me-208 – two prototypes of the Bf.108B-2 modified with tricycle gear
- Nord 1000 Pingouin – post-liberation Bf.108B-2s produced by SNCAN from existing fuselages and Argus engines
- Nord 1001 Pingouin I – 1000s fitted with the Renault 6Q-11 233 HP engine
- Nord 1002 Pingouin II – 1000s fitted with the 240 HP, right-turning 6Q-10 engine
- Nord 1100 Noralpha – the surviving Me-208 prototype
- Nord 1101 Noralpha I/Ramier – production-standard 1100s fitted with the 6Q-10 engine
- Nord 1102 Noralpha II – 6Q-11 engine model, never built
- Nord 1104 Noralpha – Potez 6Dba testbed
- Nord 1110 – two 1101s re-engined with 550 HP Turbomeca Astazou II turboprop engines