Heinkel HE 100
On the 30th of March 1939
a prototype of the new Heinkel He 100 fighter design streaked into the
record books at 746.6km/h — the new world absolute speed record.
Surprisingly it took the record away from a plane with well over twice the
horsepower, and beat it by over 40km/h. Lessons learned from earlier
Heinkel projects had been put to good use and its advanced aerodynamics
resulted in a plane that was the best performing fighter in the air, even
in its less slippery production line model.
Little information on the
plane is available, and what there is often contradictory. All we know for
sure is that Heinkel built the world's fastest plane, and it was suitable
for use as a fighter (unlike many racing planes). We also know that after
being built and proving itself in testing, the production line only built
twelve planes before shutting down. The rest of the He 100 story is
clouded in mystery, which makes it all the more interesting.
Basic specifications
Company: |
Ernst Heinkel
Flugzeugwerke GmbH |
Designer: |
Walter and Siegfried
Günther |
Year:
|
1938 |
Type:
|
Single seat day fighter
|
Description: |
Low wing monoplane
fighter with conventional control surface layout. |
Fuselage: |
Egg shaped cross section
with flattened sides, particularly around the engine. The front of the
plane is largely flat horizontally, sloping down sharply behind the
spinner. The rear of the plane slopes down toward the rear, starting at
a high point at eye level behind the cockpit and ending up roughly level
with the bottom of the canopy at the tail. |
Wings:
|
The wings are largely
rectangular, with rounded tips. The inner portion of the wing is flat on
the bottom and then bends up about 1/3rd along the span, but due to the
thinning of the wing it appears to have a slight reverse gull-wing bend.
The portion inboard of the bend is thicker with parallel leading and
trailing edges, outside of the bend the leading edge tapers back
slightly, and the trailing edge forward more strongly. Flaps span the
area inside of the bend, and ailerons start at the half way point and
run to the tips. |
Other
details: |
The canopy is similar to
the Malcolm hood from later Spitfires, in which a rounded center section
slides to the rear over smaller windows set into the fuselage. The
windscreen at the front is well rounded and the flat plate in front of
the gunsight is small and well faired. Fully retractable tail–dragger
landing gear were used, with the main gear retracting inward towards the
fuselage, the wheels laying in the thick inner portion of the wing.
|
Background
The Heinkel He 100 story
starts in 1933 with the Reichsluftsfahrtministerium
(Reich Air Ministry, or RLM) competition to
produce the first modern fighter for the re-forming
Luftwaffe. Four designs were submitted; Arado's Ar 80, Focke–Wulf's
Fw 159, Heinkel's He 112 and the Messerschmitt Bf 109. All four planes
were tested competitively in early 1936 with interim engines, and the Ar
80 and Fw 159 were quickly eliminated. Both the 112 and 109 were
considered worthy of further testing, and orders were sent out for 15
additional aircraft from both companies.
Although Heinkel was
considered the favorite to win the contract, the more modern and better
performing 109 won over the Flight Acceptance Commission. By late March of
1936 the 109 was considered the favorite. At that point Heinkel was
allowed to redesign the 112, which resulted in the largely all–new 112B.
The 112B was considerably improved and was as good or better than the 109,
but the 109 won anyway.
The 112 had a few problems
that lost it the competition. The first was that the airframe was rather
complex; it included a large number of compound curves and its elliptical
wing was labor intensive. The RLM was looking
to produced hundreds of planes, so cost in both dollars and manhours was a
factor. The prototypes also suffered from a series of accidents, even if
they weren't related to problems with the plane they still left a bad
taste in the mouth.
But the biggest problem
for the 112 was that after learning that Supermarine had started series
production of the Spitfire, the Luftwaffe was
desperate to get a modern fighter into squadron hands. Heinkel might have
won the competition had the B model been available in early 1936, but by
the time they were ready in the second half of the year the 109 was
already in series production.
Nevertheless some small
scale contracts for the plane were finally secured with a variety of air
forces in Europe and Japan. Thirty were bought by Japan, but twelve of
these were used briefly by the Luftwaffe during the
Sudetenland Crisis. Another nineteen were then sold to Spain where they
served long careers. Thirty were sold to Romania, they served in combat in
1941 but were quickly worn out. Finally three more B's were sold to
Hungary as the vanguard of a license production series that never took
place.
By 1939 production of the
He 112 ended, and it appeared that Heinkel was out of the fighter
business.
Development history
Even by early 1936 the
RLM became interested in a new fighter that
would leap beyond the performance of the Bf 109 as much as the 109 had
over the biplanes it replaced. There was never an official project on the
part of the RLM, but Roluf Lucht felt that
new designs were important enough to ask both Focke–Wulf and Heinkel to
provide "super–pursuit" designs for evaluation.
Since the super–pursuit
type was not an official recommendation, it was possible that Heinkel
would be told to stop work on the project. Thus the work was kept secret,
in a company Memo No.3657 on January 31st this was made clear; "The mockup
is to be completed by us... as of the beginning of May... and be ready to
present to the RLM... and prior to that no
one at the RLMis to know of the existence of
the mockup."
Walter Günter —one of
Heinkel's most talented designers— looked at the 112 and decided that
nothing more could be done with it. He started over with a completely new
design known as "Projekt
1035". Learning from past mistakes on the 112 project, the design was to
be as easy to build as possible while still offering good performance.
That good performance was set at an astounding 700km/h (435mph). Keep in
mind that fighters with this sort of performance didn't appear on the
battlefield until 1944.
To ease production the new
design had considerably fewer parts than the 112, and those that remained
contained considerably few compound curves. In part count the 100 was made
of 969 unique parts and was held together with 11543 rivets, in comparison
the 112 had 2885 parts and 26864 rivets. The new straight-edged wing was a
source of much of the savings, after building the first wings Otto Butter
reported that the reduction in complexity and rivet count (along with the
Butter brothers's own explosive rivet system) saved an astonishing 1150
man hours per wing.
In order to get the
promised performance out of the plane, the design included a number of
drag reducing features. On the simple end was a well–faired cockpit, the
absence of struts and other draggy supports on the tail, and fully
retractable gear (including the tailwheel) which were completely enclosed
in flight. These and similar changes applied to the 109 for the F model
would boost performance of that plane 50km/h. The engine was mounted
directly to a strong forward fuselage as opposed to internal struts, so
the cowling was very tight fitting and as a result the plane has something
of a slab sided appearance. The design used a shorter wing than the 109,
trading altitude and turn performance for speed.
In order to provide as
much power as possible from the DB 601 engine, the 100 used exhaust
ejectors for a small amount of additional thrust. In addition the
supercharger inlet was moved from the normal position on the side of the
cowling to a location in the leading edge of the left wing, where the
clean airflow improved the ram-air effect and increased boost.
For the rest of the
designed performance increase, Walter turned to the risky method of
cooling the engine via surface evaporation. Inside the engine the fluid is
kept under pressure which stops it from boiling even though it's allowed
to heat above its normal boiling point, the fluid is then run to cavity
with lower pressure where it quickly starts to boil and releases steam.
Since steam contains considerably more energy than the same temperature
water, if you can remove the steam you can remove a lot of heat. The
stream can be cooled by allowing it to condense in a series of pipes
inside the plane. With no external openings at all, it's basically a
zero-drag cooling system.
On the down side the
system is complex and hard to maintain. Worse, it greatly increases the
chance of killing the engine in combat due to a "radiator hit" on the now
much larger cooling system. Other designs would attempt to use the same
sort of design, but invariably returned to conventional radiators due to
the complexity. A number of people had already tried the system and given
up on it, but Heinkel had good experiences with it on their He 119 high
speed bomber project and decided to press ahead.
In the Heinkel system
—designed by Jahn and Jahnke— the engine was run at 110 Celsius and the
superheated fluid was then sprayed into the interior of a centrifugal
compressor, allowing the pressure to drop and steam to form. The water,
being heavier, was forced to the outside of the pump by centrifugal force
and returned to the engine. The weight of the water forced the steam into
the only available space, the inside of the pump, where it was removed.
The steam was then allowed to flow into a series of tubes running on the
inside surface of the leading edges of the wings, where it would condense
back into water and be pumped back to the engine. A number of pumping
systems were tried, and eventually a system of no less than 22 small
electric pumps (all with their own failure indicator lamp in the cockpit)
was settled on.
Unlike the cooling fluid,
oil cannot be allowed to boil. This presents a particular problem with the
DB 601 series of engines, because of a particular design technique that
results in a considerable amount of heat being transfered to the oil as
opposed to the coolant. To cool the oil a small semi-retractible radiator
was fitted under the wing.
This radiator was later
replaced on some of the prototypes with a system in which the oil was sent
to a heat exchanger where it boiled methyl alcohol to carry away the heat.
The alcohol was then cooled in a similar fashion to the engine fluid, by
running it to tubes on the top surface of the rear fuselage and leading
edge of the vertical stabilizer.
Walter was killed in a car
accident on May 25th, 1937, and the design work was taken over by his twin
brother Siegfried, who finished the final draft of the design later that
year. The wing started out flat and then bent upwards about 1/3rd along
the span, and the portions inboard of the bend were thicker to hold the
wheels. The gear retracted inward and thus were wide set when opened,
resulting in a significant improvement in ground handling over the 109.
The rear of the fuselage sloped down to the tail from a point at about eye
level at the rear of the cockpit, so while it didn't have the visibility
of the 112's bubble, it was still significantly better than the 109. A
small retractable radiator was added for running on the ground where the
surface cooling system wouldn't work. The plane was small, slightly
smaller than the 112 that spawned it, and considerably lighter.
At the end of October the
design was submitted to the RLM, complete
with details on prototypes, delivery dates, and prices for three planes
delivered to the Rechlin test center. At this point the plane was being
referred to as the He 113, but the "13" in the name was apparently enough
to prompt Ernst Heinkel to ask for it to be changed to the He 100 (even
though it had previously been given to Feiseler).
In November Messerschmitt
took the speed record for landplanes in a modified 109. In response Ernst
Heinkel made plans to use the He 100 design as a record setting plane
(less serious plans for this appear to have been in the works all along).
Much of the fuselage was as smooth as it could get, so the modifications
were limited to the canopy and a newer set of much shorter wings. The
racing version would need another airframe, so a fourth prototype was
added to the series.
In a December meeting at
the Heinkel factory with Ernst Udet and Roluf Lucht the plans were changed
slightly. V1 through V3 were to be used for testing and record attempts,
V3 sporting the clipped wings. V4 was to a testbed for series production.
The RLM went ahead with the plan, due in no
small part to Udet's (Generalluftzeugmeister,
Minister for Aircraft Production in the RLM)
plans to fly the plane in a series of record attempts.
Prototypes
The first prototype He 100
V1 flew on January 22nd, 1938, only a week after it's promised delivery
date. The plane proved to be outstandingly fast. However it continued to
share a number of problems with the 112, notably a lack of directional
stability. In addition the Luftwaffe test pilots disliked the high wing
loading, which resulted in landing speeds so great that they often had to
use breaks right up to the last 100m of the runway. The ground crews
disliked the design too, complaining about the tight cowling which made
servicing the engine difficult. But the big problem turned out to be the
cooling system, largely to no one's surprise. After a series of test
flights V1 was sent to Rechlin in March.
The second prototype
addressed the stability problems by changing the vertical stabilizer from
a triangular form to a larger and more rectangular form. The oil cooling
system continued to be problematic so it was removed and replaced with a
small semi-retractible radiator below the wing. It also received the
still–experimental DB 601M engine which the plane was originally designed
for. The M version was modified to run on "C3" fuel at 96 octane, which
would allow it to run at higher power ratings in the future.
V2 was completed in March,
but instead of moving to Rechlin it was kept at the factory for an attempt
on the 100km closed-circuit speed record. A course was marked out on the
Baltic coast between Wustrow and Müritz, 50km apart, and the attempt was
to be made at the plane's best altitude of 18000ft. After some time
cleaning out the bugs the record attempt was set to be flown by Captain
Herting, who had previously flown the plane serveral times. At this point
Ernst Udet showed up and asked to fly V2, after pointing out he had flown
the V1 at Rechlin. He took over from Hertingand flew the V2 to a new world
100km closed circuit record on the 5th of June, 1938, at 634.73km/h
(394.6mph). Several of the cooling pumps failed on this flight as well,
but Udet wasn't sure what the lights meant and simply ignored them.
The record was heavily
publicized, but in the press the plane was referred to as the "He 112U".
Apparently the "U" stands for "Udet". At the time the 112 was still in
production and looking for customers, so this was one way to boost sales
of the older design. V2 was then moved to Rechlin for continued testing.
Later in October the plane was damaged on landing when the tail wheel
didn't extend, and it's unclear if the damage was repaired.
The V3 prototype received
the clipped racing wings, which reduced span and area from 30ft 10in and
155sq ft, to 24ft 11in and 118.4sq ft. The canopy was replaced with a much
smaller and more rounded version, and all of the bumps and joints were
puttied over and sanded down. The plane was equipped with the 601M and
flown at the factory.
In August the DB 601R
engine arrived from Daimler-Benz and was installed. This version increased
the maximum RPM from 2200 to 3000, and added methyl alcohol to the fuel
mixture to improve cooling in the supercharger and thus increase boost. As
a result the output was boosted to 1776hp, although it required constant
maintenance and the fuel had to be drained completely after every flight.
The plane was then moved to Warnemünde for the record attempt in
September.
On one of the pre-record
test flights by the Heinkel chief pilot, Gerhard Nitschke, the main gear
failed to extend and ended up stuck half open. Seeing as the plane could
not be safely landed it was decided to have Nitschke bail out and let the
plane crash in a safe spot on the airfield. Gerhard was injured when he
hit the tail on the way out, and made no further record attempts.
V4 was to have been the
only "production" prototype and was referred to as the "100B" model (V1
through V3 being "A" models). It was completed in the summer and delivered
to Rechlin, so it wasn't available for modification into racing trim when
V3 crashed. Although the plane was unarmed it was otherwise a service
model with the 601M, and in testing over the summer it proved to be
considerably faster than the 109. At sea level the plane could reach
348mph, faster than the 109E's speed at its best altitude! At 6560ft it
improved to 379mph, topping out at 416mph at 16400ft before falling again
to 398mph at 26250ft. The plane had flown a number of times before its
landing gear collapsed while standing on the pad on the 22nd of October.
The plane was later rebuilt and flying by March of 1939.
Although V4 was to have
been the last of the prototypes in the original plans, production was
allowed to continue with a new series of six planes. One of the airframes
was selected to replace V3, and as luck would have it V8 was at the "right
point" in its construction and was completed out of turn. It first flew on
the 1st of December, but this was with a standard DB 601Aa engine. The
601R was then put in the plane on the 8th of January 1939, and moved to a
new course at Oranienberg. After several shakedown flights, Hans Dieterle
flew to a new record on March 30th, 1939, at 746.6km/h (463.9mph). Once
again the plane was referred to as the He 112U in the press. It's unclear
when happened to V8 in the end, it may have been used for crash testing.
V5 was completed like V4,
and first flew on November 16th. It was later used in a film about V8's
record attempt, in order to protect the record breaking plane. At this
point a number of changes were made to the design resulting in the "100C"
model, and with the exception of V8 the rest of the prototypes were all
delivered as the C standard.
V6 was first flown in
February 1939, and after some test flights at the factory it was flown to
Rechlin on the 25th of April. There it spent most of its time as an engine
test-bed. On the 9th of June the gear failed in-flight, but the pilot
managed to land the plane with little damage and it was returned to flying
condition in six days.
V7 was completed on the
24th of May with a change to the oil cooling system. It was the first to
be delivered with armament, consisting of two 20mm MG/FF in the wings and
four 7.92mm MG17's arranged around the engine cowling. This made the 100
the most heavily armed fighter of its day. V7 was then flown to Rechlin
where the armament was removed and the plane was used for a series of high
speed test flights.
V9 was also completed and
armed, but was used solely for crash testing and was "tested to
destruction". V10 was originally to suffer a similar fate, but instead
ended up being given the racing wings and canopy of the V8 and displayed
in the German Museum in Munich as the record–setting "He 112U". It was
later destroyed in a bombing attack.
Overheating problems and
general failures with the cooling system motors continued to be a problem.
Throughout the testing period failures of the pumps ended flights early,
although some of the test pilots simply starting ignoring them. In March
Kleinemeyer wrote a memo to Ernst Heinkel about the continuing problems,
stating that Schwärzler had asked to be put on the problem.
Another problem that was
never cured during the prototype stage was a rash of landing gear
problems. Although the wide-set gear should have eliminated the gear
failures that plagued the 109, the 100's were built very thin and as a
result they were no improvement. V2, 3, 4, and 6 were all damaged to
various degrees due to various gear failures, a full half of the
prototypes.
He 100D-0
Throughout the prototype
period the various models were given series designations (as noted above),
and presented to the RLM as the basis for
series production. The Luftwaffe never took them up on the offer. Heinkel
had decided to build a total of 25 of the planes one way or the other, so
with 10 down there were another 15 of the latest model to go. In keeping
with general practice, any series production is started with a limited run
of "zero-series" machines, and this resulted in the He 100D-0.
The D-0 was similar to the
earlier C models, with a few notable changes. Primary among these was a
larger vertical tail in order to finally solve the stability issues. In
addition the cockpit and canopy were slightly redesigned, with the pilot
sitting high in a large canopy with excellent vision in all directions.
The armament was reduced from the C model to one 20mm MG/FF-M in the
engine V firing through the propeller spinner, and two 7.92mm MG17's in
the wings close to the fuselage.
The three D-0 planes were
completed by the summer of 1939 and stayed at the Heinkel Marienehe plant
for testing.
He 100D-1
The final evolution of the
short He 100 history is the D-1 model. As the name suggests the design was
supposed to be very similar to the pre-production D-0's, the main planned
change was to enlarge the horizontal stabilizer
But the big change was the
eventual abandonment of the surface cooling system, which proved to be too
complex and failure prone. Instead an even larger version of the
retractable radiator was installed, and this appeared to completely cure
the problems. The radiator was inserted in a "plug" below the cockpit, and
as a result the wings were widened slightly.
While the plane didn't
match it's design goal of 700km/h once it was loaded down with weapons,
the larger canopy and the radiator, it was still capable of speeds in the
400mph range. A low drag airframe is good for both speed and range, and as
a result the He 100 had a combat radius between 900 and 1000km compared to
the 109's 600km. While not in the same league as the later escort
fighters, this was at the time a superb range and may have offset the need
for the 110 to some degree.
By this point the war was
underway, and as the Luftwaffe would not purchase the plane in its current
form, the production line was shut down.
Specifications for the He
100D-1c
Engine: |
1,175hp (876kW)
Daimler-Benz DB 601M liquid–cooled inverted V12 |
Dimensions: |
span 9.42m (30ft 10
3/4in)
length 8.20m (26ft 10 3/4in)
height 3.60m (11ft 9 3/4 in) |
Weights: |
empty 2070kg (4,563lb)
max loaded 2500kg (5,512lb) |
Wing
Area: |
14.5m2
(156ft2)
|
Wing
Loading: |
29.25lbs/ft2
|
Performance: |
maximum speed 668km/h at
6400m (416mph at 21,000ft)
560km/h (348mph) at sea level
cruise speed unknown
service ceiling 11000m (36,090ft)
range 900km (559miles) |
Armament: |
one 20mm MG/FF-M firing
through the propeller spinner
two 7.92mm MG17 in the wings |
He 100 in service
In 1940 the He 100's were
publicized by Goebbels in a propaganda effort aimed at convincing people
that a new fighter was entering service with the Luftwaffe. The plan
involved taking pictures of the remaining D-1's at different air bases
around Germany, each time sporting a new paint job for various fictional
fighter groups. The pictures were then published in the press with the He
113 name, sometimes billed as night fighters (rather silly since you could
see they didn't even have a landing light).
The plane also appeared in
a series of "action shot" photographs in various magazines like
Der Alder, including claims that it had proven
itself in combat in Denmark and Norway. One source claims that the planes
were on loan to the one Luftwaffe staffel in Norway for a time, but this
might be a case of the same misinformation working many years later.
It's unclear even today
exactly who this effort was intended to impress —foreign air forces or
Germany's public— but it seems to have been a successful deception.
British intelligence featured the plane in AIR 40/237, a report on the
Luftwaffe that was completed in 1940. There the top speed was listed as
390mph (interesting that it also states the wing was 167 square feet) and
it noted that the plane was in production. Reports of 113's encountered
and shot down were listed throughout the early years of the war.
The remaining twelve He
100D-1c fighters were used to form Heinkel's Marienehe factory defense
unit, flown by factory test pilots. They replaced the earlier He 112's
that were used for the same purpose, and the 112's were later sold off. At
this early stage in the war there were no bombers venturing that far into
Germany, and it appears that the unit never saw action. The eventual fate
of the D-1's remains unknown.
Foreign use
When the war opened in
1939 Heinkel was allowed to look for foreign licensees for the design.
Japanese and Soviet delegations visited the Marienehe factory in late
October, and were both impressed with what they saw. Thus it was in
foreign hands that the 100 finally saw use, although only in terms of
adopted design features.
The Soviets were
particularly interested in the surface cooling system, and in order to
gain experience with it they purchased the six surviving prototypes (V1,
V2, V4, V5, V6 and V7). After arriving in the USSR they were passed onto
the ZAGI institute for study, there they were analyzed and its features
influenced a number of Soviet designs, notably the LaGG-3. Although the
surface cooling system wasn't copied, the addition of larger Soviet
engines made up for the difference and the LaGG-3 was a reasonably good
performer. It's perhaps ironic that German planes would later be shot down
by German inspired planes.
The Japanese were also
looking for new designs, notably those using inline engines where they had
little experience. They purchased the three D-0's for 1.2 million DM, as
well as a license for production and a set of jigs for another 1.8 million
DM. The three D-0's arrived in Japan in May 1940 and were re-assembled at
Kasumigaura. They were then delivered to the Japanese Naval Air Force
where they were re-named AXHei, for "Experimental Heinkel Fighter". When
referring to the German design the plane is called both the He 100 and He
113, with at least one set of plans bearing the later name.
In tests the Navy was so
impressed that they planned to put the plane into production as soon as
possible as their land-based interceptor — unlike every other forces in
the world, the Army and Navy both fielded complete land-based air forces.
Hitachi won the contract for the plane and started construction of a
factory in Chiba for its production. With the war in full swing in Europe
however, the jigs and plans never arrived. Why this wasn't sorted out is
something of a mystery, and it appears there isn't enough information in
the common sources to say for sure what happened.
The DB 601 engine design
was far more advanced than any indigenous Japanese design, which tended to
concentrate on air cooled radials. To get a jump into the inline field,
Kawasaki had already purchased the license for the 601A from Daimler Benz
in 1938. The adoption process went smoothly, they adapted it to Japanese
tooling and had it in production by late 1940 as the Ha-40.
At the same time Kawasaki
was working on two parallel fighter efforts, the Ki-60 heavy fighter and
the Ki-61. The former was abandoned after poor test results (the test
pilots disliked the high wing loading, as they always did) but work
continued on the lightened Ki-61 with the Ha-40 engine. The Ki-61 was
clearly influenced by the He 100.
Like the D's it lost the
surface cooling system (although an early prototype may have included it),
but is otherwise largely similar in design except for changes to the wing
and vertical stabilizer. Since the Ki-61 was supposed to be lighter and
offer better range than the Ki-60, the design had a longer and more
tapered wing for better altitude performance. This also improved the
handling to the delight of the test pilots, and the plane was put into
production. The Hien would prove to be the first of the Japanese planes
that was truly equal to the contemporary US fighters.
Further developments
In late 1944 the
RLM went shopping for a new high altitude
fighter with excellent performance. It's unclear exactly why this
happened, as the Ta 152H version of the Fw 190 was currently in limited
production for just this task. Nevertheless Heinkel was contracted to
design such a plane, and Siegfried Günter was placed in charge of the new
"Projekt 1076".
The resulting design was
similar to the He 100, but many detail changes resulted in a plane that
looked all-new. It sported a new and longer wing for high altitude work,
which lost the gull-wing bend and was swept forward slightly at eight
degrees. Flaps or ailerons spanned the entire trailing edge of the wing
giving it a rather modern appearance. The cockpit was pressurized for high
altitude flying, and covered with a small bubble canopy that was hinged to
the side instead of sliding to the rear. Other changes that seem odd in
retrospect is that the gear now retracted outward like the original 109,
and he re-introduced the surface cooling system. Planned armament was one
30mm MK 103 cannon firing through the propeller hub, and two wing-mounted
30mm MK 108 cannons.
The use of one of three
different engines was planned: the DB 603M with 1825hp, the DB 603N with
2750hp or the Jumo 213E with 1750hp (the 603M and 213E both supplied
2100hp using MW-50 water injection). Performance with the 603N was
projected to be a shocking 880km/h (546mph), which would have stood as a
record for many years even when faced with dedicated racing machines.
Performance would still be excellent even with the far more likely 2000hp
class engines, the 603M was projected to give it the equally amazing speed
of 855km/h (532mph).
These figures are somewhat
suspect though, and are likely just optimistic guesses that could not have
been met — something Heinkel was famous for. Propellers loose efficiency
as they approach the speed of sound, and eventually they no longer provide
an increase in thrust for an increase in engine power. Even the advanced
counter-rotating VDM design is unlikely to have been able to effect this
problem too much.
The design apparently
received low priority, and it was not completed by the end of the war.
Siegfried Günter later completed the detailed drawings and plans for the
Americans in mid-1945.
Conclusions
In 1939 the He 100 was
clearly the most advanced fighter in the world. It was even faster than
the Fw 190, and wouldn't be bested until the introduction of the F4U in
1943. Nevertheless the plane was not ordered into production. The reason
the He 100 wasn't put into service seems to vary depending on the person
telling the story, and picking any one version results in a firestorm of
protest.
Some say it was politics
that killed the He 100. However this seems to stem primarily from
Heinkel's own telling of the story, which in turn seems to be based on
some general malaise over the He 112 debacle. The fact is that Heinkel was
well respected within the establishment regardless of Messerschmitt's
success with the 109 and 110, and this argument seems particularly weak.
Others blame the bizarre
production line philosophy of the RLM, which
valued huge numbers of single designs over a mix of different planes. This
too seems somewhat suspect considering that the Fw 190 was purchased
shortly after this story ends.
For these reasons I have
chosen to accept the RLM version of the story
largely at face value; that the production problems with the DB series of
engines was so acute that all other designs based on the engine were
canceled. At the time the DB 601 engines were being used in both the 109
and 110 aircraft, and Daimler couldn't keep up with those demands alone.
The RLM eventually forbade anyone but
Messerschmitt to receive any DB 601's, leading to the shelving of many
designs from a number of vendors. After all, the 109 and 110 were better
than anything out there, so another plane that was even better
didn't seem important at all.
The only option open to
Heinkel was a switch to another engine, and the RLM
expressed some interest in purchasing such a version. At the tim the only
other useful inline was the (inferior) Junkers Jumo 211, and even that was
in short supply. However the design of the He 100 made adaptation to the
211 difficult. Both the cooling system and the engine mounts were designed
for the 601, and a switch to the 211 would have required a redesign.
Heinkel felt it wasn't worth the effort considering the plane would end up
with inferior performance, and so the He 100 production ends on that sour
note.
For this reason more than
any other the Fw 190 became the next great plane of the Luftwaffe, as it
was based around the otherwise unused BMW 139 (and later BMW801) radial
engine. Although production of the engines was only starting, the lines
for the airframes and planes could be geared up in parallel without
interrupting production of any existing design. And that's exactly what
happened.
Notes
Another chapter about the
operational use of the He 100 is referred to in Len Deighton's fictional
work Bomber. In the book he tells the story of an RAF
Mosquito pathfinder/marker being shot down by a nitrous-oxide (GM-1
presumably) equipped He 100. The use of laughing gas on the Heinkel
suggested the plane's nickname, the plane was referred to as the "he he".
This account entirely fictional, but still, one wonders where the idea
came from.
[A reader noted that in
his version of the book the plane in question is a Ju 88S. My recollection
might be faulty. Interestingly the 88S was a bomber-only version, and
could not have been used in this role!]
There is some disagreement
on various measures depending on the source, this appears to be due to the
limited number of records left for the plane. Common disagreements are on
the service ceiling, and the empty weight is also often listed at 1810kg
(3,990lb). Another issue is the overall height of the plane which is
sometimes listed at 2.5m. I believe this is in error in this case, the
other common figure of 3.6m is used because that is likely correct for the
enlarged tail of the D-1 models.
Most importantly it should
be noted that almost all of the planes underwent engine modifications and
tweaking during their lifespan. The 650km/h speed is almost universally
quoted for the D-1 models, but it may be the case that this is the speed
of the earlier and more slippery V4 "A" model.
After reading the earlier
versions of this article, a number of people expressed their concerns with
this figure, and suggested further research. In the meantime it is quite
likely that the AIR 40/237 number in the 390mph range is accurate for the
production plane.
All measures and
performance data in the table are for the D-1 production model, and taken
from the primary source listed in the Sources section. I have used metric
values as the primary form of measurement in most cases, with the
exception of engine power. This might seem arbitrary, but it appears this
is the way most people prefer to see them. Conversions for power use 1 hp
= 550 ft.lbs/s = 745.6W.
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