From: jfb200@cbnewsd.cb.att.com (joseph.f.baugher)
Subject: Re: Focke-Wulf Ta 152
Organization: AT&T Bell Laboratories -  Naperville, Illinois
Date: Mon, 28 Dec 1992 21:58:28 GMT
Summary: Blohm und Voss BV 155
Keywords: Kurt Tank's finest

In article <1992Dec28.141340.7902@cbnewsi.cb.att.com>, acura@cbnewsi.cb.att.com (james.r.feeney) writes:
>
> Joe, 
> 
> I seem to remember seeing a picture of a high altitude version of the Bf-109
> that was under development at the end of the war. Actually the plane had 
> little resemblance to a 109. It had very long wings with radiators for the
> engine mounted midway down each wing in streamlined pods. I don't think any
> versions flew. I wonder if Messerschmidt developed it in response to Kurt
> Tank's work. Do you have any info on this plane?
> 

I believe that you are  referring to the  Messerschmitt  Me 155, which
started life as a carrier-based  single-seat fighter.   The design was
handed  off to Blohm  und  Voss,  and  it  evolved  in stages until it
eventually emerged as a high-altitude interceptor. I posted an article
on the BV 155 in sci.military last June,  and here  is a  copy of that
article for those of you who are interested in this unusual aircraft.

The BV 155 high-altitude  interceptor is almost a textbook example  of  
how NOT to design a  combat  aircraft.   It  went through an agonizing 
number of  design changes,  starting off  its life  as  a  single-seat  
carrier-based  fighter, gradually  evolving into a  precision  bomber,     
then going through several incarnations as a high-altitude interceptor.  
It even went through a change of MANUFACTURERS.  Here is a summary of 
its history.

The saga of the BV 155 high altitude  interceptor  actually  began  at
Messerschmitt in the spring of 1942.  At that time, it was known under
the designation of Me 155, and was a company proposal for  a  carrier-
based single seat fighter.  The Me 155 was intended to be based aboard
the *Graf Zeppelin* aircraft carrier, then under construction.  In the
interest  of  economy and simplicity, the Me 155 was to use as many Bf
109 components as possible, being basically a navalized version of the
earlier  Messerschmitt  fighter.  The Me 155 was to be powered by a DB
605A-1 liquid-cooled engine of 1475 hp.  The fuselage was more-or-less
that  of  the  standard  Bf  109G, but with an entirely new wing.  The
undercarrage retracted inwards into wing wells,  providing  the  wider
track  required  for  safe  carrier landings. Standard naval equipment
such as folding wings, catapult spools, and arrester gear were  to  be
fitted.   Proposed  armament was an engine mounted 20-mm MG 151 cannon
and two 20-mm MG 151 cannon and two  13-mm  MG  131  machine  guns  in
wings.  Estimated maximum speed of 403 mph.

Detail design of the Me 155 was complete by Sept 1942.   However,  the
numerous  delays  in  the  *Graf Zeppelin* seemed to indicate that the
launching  of  the  carrier  would  be  at  least  two   years   away.
Messerschmitt was told to shelve the Me 155 project for the indefinite
future.  In the  event,  work  on  the  *Graf  Zeppelin*  carrier  was
abandoned in favor of more submarines.

In order that all of that work on the Me 155 project not  go  entirely
to waste, Messerschmitt adapted its design in November 1942 to fulfill
a Luftwaffe requirement for a fast single seat bomber.  A single  2205
lb  SC  1000 bomb was to be carried.  All of the carrier equipment and
most of the armament was removed from the aircraft.   Additional  fuel
cells  were  provided and an elongated, non- retractable tailwheel was
added to provide ground clearance for the large  bomb.   The  proposal
was designated Me 155A.

By the end of 1942, the increasing number of USAAF bombing  raids  and
intelligence  coming  in  about  the  new American B-29 bomber led the
Luftwaffe to envisage  a pressing need for an effective  high-altitude
interceptor.   The  Messerschmitt  outfit  adapted  its design to this
requirement under the designation Me 155B. The engine was to be the DB
628,  which  was  basically  a  DB  605A  with  a two-stage mechanical
supercharger with an induction cooler.  A pressure  cabin  was  to  be
provided.   It  was  estimated  that  a service ceiling of 46,250 feet
could be attained.

A converted Bf 109G adapted to take the DB 628 engine flew in May 1942
and  attained an altitude of 50,850 feet.  However, the Technische Amt
concluded   that   a   DB   603A   engine   with   an   exhaust-driven
turbosupercharger  was  more  promising.  The DB 603A provided 1610 hp
for takeoff and 1450 hp at 49,210 feet.  This engine  change  required
that the fuselage be elongated in order to house the turbosupercharger
aft of  the  pressure  cabin.   Exhaust  gases  were  carried  to  the
turbosupercharger  via external ducts.  Air was drawn in through via a
ventral trough aft of thw wing.  Standard Bf 109G  wings  were  to  be
fitted  outboard  of  a new, long-span, untapered wing center section.
Other parts were scavenged from  existing  Messerschmitt  designs--the
vertical  tail  was  from  the Me 209, and the horizontal tail and the
undercarriage were taken from the Bf 109G.

In August 1943, the Technische  Amt  decided  that  Messerschmitt  was
over-committed, and they decided to transfer the work on the design to
the Blohm und Voss outfit.  After some initial study,  the  Blohm  and
Voss design team deemed that the existing Messerschmitt design had too
many weaknesses.   Several  months  of  argument  and  finger-pointing
between  the  Messerschmitt  transition  team  and  the Blohm und Voss
designers followed.  Friction  between  the  two  teams  got  steadily
worse.   In  the  event, no meeting of the minds was possible, and the
Technische Amt eventually  decided  to  throw  Messerschmitt  off  the
project entirely, and turn it entirely over to Blohm und Voss.

The Blohm und Voss  team  elected  to  adopt  a  laminar-flow  airfoil
section,  and  abandoned  the idea of using standard Bf 109G wings for
the outer panels.  The wing center section was redesigned.  Two  large
radiators were mounted over the wing trailing edges at the extremeties
of the center section.  Ju 87D-6 undercarriage legs  and  wheels  used
instead  of  the  Bf 109G units.  The Bf 109G horizontal tail surfaces
were  replaced  with  larger  area  freshly-designed  units,  and  the
vertical tail surface was increased in size.

The first prototype was designated BV 155 V1, and flew for  the  first
time  Sept  1,  1944.  Tests  with  the  V1  showed  that the outboard
radiators  were  not  sufficently  effective  in  providing   cooling,
especially  at  high  angles  of  attack.   The  intakes  on  the next
prototype were enlarged and underslung beneath the  wing  rather  than
placed  over  it.   However,  the  enlarged  radiators  caused an c.g.
problem, which required moving the pressurized cockpit  forward.   The
Blohm  und  Voss team took this opportunity to replace the original Bf
109G canopy with an aft-sliding all-round vision canopy, and the  rear
fuselage  decking  was  cut down.  This in turn required that a larger
rudder be fitted.  The ventral radiator bath was also enlarged.

All these changes were incorporated into the BV 155 V2, which flew for
the  first  time  on February 8, 1945.  which was the first genuine B-
series aircraft.  The Blohm und Voss team was still not satisfied with
the  design,  and before the V-2 began its flight trials they proposed
that the  engine  be  switched  to  the  DB  603U  having  the  larger
mechanically-driven supercharger of the DB 603E.  The DB 603U promised
a power of 1660 hp for takeoff  and  1430  hp  at  49,000  feet.   The
ventral  turbosupercharger was retained.  The Technishe Amt decided to
accept this proposal, and abandoned all work on the BV 155B  in  favor
of the revised design, which was designated BV 155C.

The BV 155C was quite different in appearance from  the  BV-155B.  The
clumsy  wing-mounted radiators of the BV-155B were eliminated, and the
main landing gear leg attachment points were moved inboard to  retract
inwards.  The cooling was provided by an annular frontal radiator a la
Ta 152.  Large circular intakes were attached to  the  fuselage  sides
above the wing roots.

In the meantime, the BV 155 V2 was damaged beyond repair during a  bad
landing.  It  was to be replaced in the test program by the BV 155 V3.
The BV 155 V3 differed from the V2 in having the DB 603 U intended for
the  BV  155C.  However, the engine cowling and turbosupercharger were
unchanged.

Various armament schemes for the BV 155B were proposed.  One  proposal
had an engine-mounted 30-mm MK 108 cannon and two 20-mm MG 151 cannon.
Another had an engine- mounted MK 103 cannon and two wing-mounted  15-
mm  MG 151 cannon.  Estimated maximum speed was 404 mph at 39,370 feet
and 429 mph at 52,490 feet.  Service ceiling was to  be  55,610  feet.
Empty  weight was 10,734 lbs.  Normal loaded weight ranged from 11,300
to 12,100 lbs, depending on the armament provided.

The program was brought to an abrupt end when the Allies occupied  the
Blohm  und  Voss  factory  at  Finkenwerder in April of 1945.  At that
time, the V3 was 75 percent completed, but assembly  of  the  C-series
prototypes had not yet commenced.  The V-3 was eventually taken to the
USA for examination.  I am unaware of its  ultimate  fate.   

Source: Warplanes of the Third Reich, William Green, Doubleday, 
	New York, 1970.


Joe Baugher			**************************************
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