From: Joseph F Baugher <jfb@ihlpl.att.com>
Subject: Re: Horten-9
Summary: Horten Ho.IX/Gotha Go 229 flying wing fighter
Organization: AT&T Bell Laboratories -  Naperville, Illinois
Date: Thu, 12 Nov 1992 17:36:00 GMT


From Joseph F Baugher <jfb@ihlpl.att.com>

In article <BxID0J.LC3@law7.DaytonOH.NCR.COM>, Stig-Lennart Soerensen <stigs@stud.cs.uit.no> writes:
> 
> 
> Last saturday, 7 september, I saw a science-show called Equnix, with the title:
> The Art of Deception, on the european Discovery channel.
> 
> In this very interesting program, they showed several examples of the technology
> and history connected to the development of radar-evading airplanes, or
> stealth as it called today.
> 
> One of the earliest examples of trying to construct a plane which would render
> itself virtually invisible to a radar, was the german fighter-bomber (?) Horten-9.
> 
> The Horten-9 airplane was a revolutionary design, buildt by nazi scientist in the
> last months of the second world war.
> 
> It was a delta-shaped aircraft, with its two jet-engines hidden inside the wings
> to prevent radar-detection. It was buildt primarly of wood, and used a glue which
> according to rumours was less detectable to radar. Its shape was not unlike the
> american B-1 (the stealth plane of today), with a very low flat shape and the
> cockpit hidden inside the 'wing' shape of the plane.
> 
> The germans buildt two prototypes, one which chrashed test-flying, and the other
> one ended up in the Washington aerospace museum (I belive), where it is stored
> today.
> 
> According to the program, the germans planned to build a large, six engine bomber
> model, which could deliver an (if the germans won the bomb-race) atomic bomb over
> the USA. This plane was also delta-shaped.
> 
> Now I would like to know if there is anyone who has some more data on this plane
> which surely could have changed the history if put in production early and
> produced in large numbers.

Speaking of the Ho.IX/Go 229......Here's a copy of an article I posted
a few months back about this interesting fighter.    Hope that this is
still interesting.

The Gotha Go 229 was the first turbojet-driven warplane of pure flying
wing  configuration.   Although  flown for the first time in 1945, the
aircraft looks surprisingly modern--almost like a small version of the
Northrop B-2 stalth bomber.

The Go 229 was initially designed by the brothers  Reimar  and  Walter
Horten,  pioneers  in  early flying wing aircraft designs.  The Horten
brothers were attempting to figure out ways to eliminate every  sourse
of  parasitic  drag.  They believed that the flying wing configuration
offered the  best  way  to  achieve  this  feat.   Their  flying  wing
proposals  had  no  fuselage  as  such, and they looked a lot like the
Northrop flying wing designs produced in the USA during the 1940s  and
later.  The chord of the wing center section increased sufficiently to
enable pilot and powerplants to be housed  entirely  within  the  wing
itself  without  any drastic increase of thickness/chord ratio.  There
were  no  vertical  surfaces--lateral  and  directional  control  were
provided by a set of spoilers.

The Horten brothers' interest in flying wings dates back to the Horten
I  wooden  sailplane  of  1931.   The  brothers  produced  a number of
experimental powered and unpowered flying wings throughout the  1930s.
In  1943,  they  began  to  envisage a jet fighter flying wing design,
designated Ho IX.  The Ho IX was to be powered by a pair  of  BMW  003
turbojets.    The Ho IX was what was later to be known colloquially as
a "skunked" project-- it went forward initially  without  the  support
(or  even the knowledge) of the all-powerful Reichluftfahrtministerium
(RLM, the State Ministry of Aviation).  Work  on  a  single  prototype
(designated Ho IX V1) was begun at Gottingen.

The Horten brothers planned that their Ho IX  V1  was  to  undergo  an
extensive series of gliding tests before any attempt was to be made to
install the pair of BMW 003 turbojets.  However, in  early  1944,  RLM
became  aware  of  the existence of the Ho IX V1. The project captured
the imagination of Reichsmarschall Hermann Goering  who  gave  it  his
enthusiastic  backing.  In addition, intelligence reports from the USA
indicated that the Northrop Corporation  was  thinking  along  similar
lines.   The  Ho  IX  project  was  to  move forward to powered flight
testing with all deliberate speed.

With official backing now present, the Ho IX project gained  momentum.
The first gliding trials began in spring of 1944.   Gliding tests were
highly satisfactory.  The planned installation of the BMW 003 turbojet
engines  in  the Ho IX V1 prototype was deemed impractical, and it was
decided to install a pair of Jumo 004 engines in the second  prototype
(Ho IX V2).

The Ho IX V2 was designed for a  7g  safe  load  factor.   The  center
section of the wing housed the engines and the cockpit and was made of
conventional welded steel-tube construction.  The center  section  was
covered  with plywood skinning except in the immediate vicinity of the
engine exhausts, where metal was  used.  The  outer  wings  were  made
entirely  of wood.  The outer wing leading edges were constructed of a
special molded wood (wood shavings compressed  with  resin),  but  the
rest  of  the  wing  was  covered  with plywood.  A special coating of
lacquer was applied to give a smooth finish to the entire aircraft.  I
think   that   the   idea  of  the  lacquer  finish  was  to  give  an
aerodynamically smooth surface rather than to  provide  any  "stealth"
characteristics--that was still many, many years in the future.

Two Jumo 004B turbojets were mounted side-by-side close inboard in the
center  section.   The  jet  tailpipes  protruded  above the wing rear
surfaces.    A  tricycle  undercarriage  was  fitted.    Lateral   and
longitudinal  control  was  provided  by  elevons which, together with
plain flaps, occupied the trailing edges of  the  outer  wing  panels.
Spoiler  flaps  extended  across  most  of  the  wing  center  section
immediately aft of the  mainwheel  wheels.   Directional  control  was
achieved  by  spoilers  located near the wingtips just aft of the main
spar.

Glide tests with the Ho IX V1 were sufficiently encouraging  that  the
RLM  decided  that  the  Horten  design was worthy of production as an
operational  combat  aircraft.   In  early   summer   of   1944,   the
Friedrichsroda  facility  of  the  Gothaer  Waggonfabrik  was  given a
contract for the production of the design  under  the  designation  Go
229.  Control of the adaptation of the design for production was taken
away from the Horten brothers, but the brothers continued to  work  on
the testing of their Ho IX prototype.

Gotha immediately began work on the  production  of  the  flying  wing
fighter.    The  initial  production  version  was  to  be  given  the
designation Go 229A. The Gotha team found it  necessary  to  introduce
some  changes  in  order  to  adapt  the  Ho  IX  for production. They
redesigned the cockpit, enlarged the turbojet  housings,  revised  the
air  intake  geometry  and  modified the undercarriage.  Provision was
made for four 30 mm MK  103  or  MK  108  cannon  mounted  immediately
outboard  of  the engines.  Hardpoints were to be provided beneath the
center section for two 2205-lb bombs or for  two  275  Imp  gall  fuel
tanks.   A  two seat radar-equipped all-weather version (designated Go
229B) was also envisaged.

In the meantime, the Ho IX V2  was  transferred  in  January  1945  to
Oranienberg for powered flight testing.  Flight tests went quite well.
Handling characteristics were much better than  expected.   A  maximum
level  speed  of 497 mph was attained during the tests. Unfortunately,
the Ho IX  V2  crashed  during  a  landing  attempt  and  was  totally
destroyed.

Gotha's  first  production  prototype  for  the  Go  229A  single-seat
fighter-bomber  series was given the designation Go 229 V3.  V4 and V5
were to be the prototypes for the Go 229B alweather fighter,  and  V-6
was  to  be a second A-series prototype with MK 103 cannon in place of
MK 108s.  V7 was to be a prototype for a two-seat training version.

All through the spring of 1945, work proceeded  at  Friedrichsroda  on
these  prototypes.   However,  late in April, the Friedrichsroda plant
was finally occupied by American troops and developmenent came  to  an
abrupt end.  At that time,  the Go 229 V3 prototype was being prepared
for flight testing, and  the  V4  and  V6  prototypes  were  in  final
assembly.   Component  manufacture for the 20 pre-production Go 229A-0
fighter bombers was well advanced, and various  component  parts  were
found strewn about the factory.

The Go 229A-0 pre-production fighters were to be powered by a pair  of
Junkers  Jumo  004B-1,  -2,  or  -3  turbojets of 1962  lb. st.  each.
Estimated maximum speed was 590 mph at sea level and 607 mph at 39,370
feet.   Maximum ceiling was to be 52,500 feet (!!!  Remember, this was
only 1945, folks!).  Maximum range was estimated  at 1180  miles,  and
initial  climb  rate was to be 4330 ft/min.  Weights were estimated at
10,140 lb empty, 16,550 lbs. normal loaded.

[note added: I was recently at the Paul Garber Restoration Facility in
Suitland, Maryland.  The Go 229 airframe wasn't there,  or at least it
wasn't in any of the buildings we were  allowed  to see.   However, it 
could very  well be  tucked away  in some  forgotten corner in another
building.  Anyone know for sure?]

  Source: Warplanes of the Third Reich, William Green.  Doubleday, 
         New York, 1970.
 
Joe Baugher       AT&T Bell Laboratories   Naperville, Illinois