In World War 2 there was a German firm named Blohm und Voss
(BV). Under guidance of the technical director Dr.-Ing. Richard
Vogt, they produced one of the weirdest airplanes ever.
In 1937 RLM (Reichsluftfahrtministerium) asked for a short range
reconnaissance aircraft capable of fulfilling the light bomber, low
level attack and smokescreen-laying roles in an emergency.
Specifications were:
- Three seats
- Good all-round view
- 850-900 hp for take-off
The specifications were sent by RLM to Arado and Focke-Wulf.
Dr.-Ing. Richard Vogt had an unusual idea about all-round view and
single engines and made a private-venture proposal. Its name was
Blohm und Voss BV 141.
His idea was to place the fuselage and the engine off center.
When you look at the drawing of the airplane, you probably will
react with "Huh?". Yes, it looks strange. You might think that this
airplane will not be stable in flight. Sorry, you are wrong. It was
even a very stable airplane. In fact, it was even more stable than
the "normal" single engine airplanes.
To understand this you need to look at the following drawings.
There you will see what forces are created in a conventional single
engine airplane and how the design of Blohm und Voss became more
stable.
Here you see what forces are present on a conventional airplane.
There is a moment created by the rotation of the engine and prop.
The airflow that hits the tail creates a left turn.
The center of gravity, which is placed to the right of the
geometrical center, compensates the moment created to the engine
and prop. The drag of the fuselage compensates the tendency to turn
to the left created by the airflow that hits the tail. There is no
longer the tendency to turn to the left.
The plane flew well. Even the critics had to admit that. But the
project had some troubles. There were some belly landings due to
failure of the hydraulic system, which operates the landing gear.
This and the desire to ensure the production of the Focke-Wulf Fw
200 Condor (which took place on 80% of the assembly shop space at
Blohm und Voss after a bombing raid on the Focke-Wulf plant) made
the RLM choose the reliable Focke-Wulf Fw 189.
The Fw 189 was a surprise to the RLM, because it had two
engines. The specification, made by the RLM, did not mention that
the total power had to be delivered by one engine. But everybody,
except Focke-Wulf, didn't consider the choice of two engines.
It is my idea that the RLM made a right choice here due the
unreliability of the BV 141. The Fw 189 proved to be an excellent
airplane. It is still one of my favorite "normal" airplanes.
|
Data of BV 141B-02
(V10)
|
| Seats |
3 |
| Power plant (1 BMW 801-A-0) |
1560 hp at take-off |
| Maximum speed |
368 km/h |
229 mph at sea level |
| 438 km/h |
272 mph at 16400 ft |
| Range (normal) |
1.200 km |
745 mls |
| Range (maximum) |
1.900 km |
1180 mls |
| Service ceiling |
10.000 m |
32 810 ft |
| Weight (empty equipped) |
4.724 kg |
10 362 lb |
| Weight (normal loaded) |
5.728 kg |
12 566 lb |
| Weight (maximum) |
6.130 kg |
13 448 lb |
| Span |
17,45 m |
57 ft 3 1/3 in |
| Length |
13,95 m |
45 ft 9 1/4 in |
| Height |
3,60 m |
11 ft 9 3/4 in |
| Wing area |
52,90 m2 |
569.41 sq. ft |
You will see that the engine in the data is more powerful than
the specification mentioned in this page. The reason for that is
that in the development of the BV 141 more power was needed.
Luckily Dr.-Ing. Richard Vogt had foreseen this demand and made the
original design accessible for larger engines.
In my books I found an article about a
similar design, the Da-U. It is a design of
prof.-ing.-doctor M. L. Tudha (university of Grönfeldesz). It is a
double engine airplane. But here the two engines are placed behind
each other. One engine drives a tractor prop, the other a pusher
prop. Both engines are placed in the same "nacelle" (don't know if
this is the right word) on the right of the fuselage. It has the
advance that the door on the left of the fuselage is totally free
from the props. The noise level in the cockpit should be good if
you place the silencers on the right side of the nacelle.
It is not clear to me if this airplane ever flew. The article
mentions another design from the same person but this time with a
single seat. At the time of the article (1968) this last airplane
was in development.
Another airplane with an asymmetrical layout is the
Ares (Agile-Response Effective Support) from
Scaled Composites (the famous Burt Rutan is part
of this firm, probably leading part). It is describes as a
close-air-support/anti-helicopter fighter.
The turbofan and the inlet are 8° offset to the left. And the
fuselage is offset to the right of the wing centerline. The reason
is not stability. The gasses, produced by the firing General
Electric GAU-12/U 25 mm cannon (sounds like a big gun to me), may
not get into the engine. That is why the inlet is offset.
During flight there is some trim needed when applying more
thrust.
This airplane was designed as a low-cost airplane with some
low-observable features especially for export.
Interested in seeing this airplane flying. Go to your local
video store and lean the video "Aces: Iron Eagle III" (1992 by John
Glen (USA)). The Ares is shown at the end of the film. They mention
it as the Me 263 (but you need to know that this reference is just
a fantasy by the filmmakers). If you need to know more about the
real Me 263, go see www.luft46.com! Anyhow, it is a
nice view of the Ares.
Scaled Composites has a nice site. www.scaled.com
In our site there will be descriptions of some other products of
this firm soon.
I made a personal design where I try to combine the stability of
an asymmetrical design with the possible benefits of a flying wing.
Go see the section "Few of my thoughts".
There is another design, which uses an asymmetric shape. It is
the Boomerang of Burt Rutan. You can see this
airplane on several pages of the web. I include some quotes from
the nurflugelmailinglist about this airplane.
Now just look at the Boomerang. Admit ...it is a beauty. And it
flies reeeaaally good i read somewhere. I wished i could tell more
about its flying. Maybe some day the current owner will tell
me.
Later I got this reaction.
From: win@writer.win-uk.net (David) Date: Mon, 22
Feb 1999
"I was curious about the different power output
of the Boomerang's engines, but all became clear when Burt Rutan
told me it was really very simple: he already had one engine and
got a good deal on the other! David"
It sure was funny to see the rather usual reason to
create an unusual airplane.
I got this reaction after showing my idea about an asymmetric
flying wing (see section "Few thoughts")
From: Lars Mathiesen Date: Mon, 22 Feb 1999
"Hey Koen. I think there's some other approac A 2 engine
design like Burt Rutans Boomerang. He uses 2 engines with a
slightly different power output off 200hp and 210hp, this could be
a 4 solution. Burt Rutan off cource has to have an asymmetric plane
for his personal use. He has some experience in asymmetric design
from the AD-1. The scissors wing concept (a fifth solution! with a
rotating cockpit/engine nacelle) was originally designed by the
designer off the BV 141 (can't remember his name) Sez Il
PS!"
AD-1 picture can be found here:
On 14-4-2000 I got this remark from Paul Dunlop
(www.geocities.com/aerohydro):
"You might be interested to know that the first aircraft,
the Wright Brother's 1903 Flyer was also a mildly
asymmetrical craft. It's generally known that the prone pilot and
the engine were located side-by-side on the lower wing and hence
the Flyer has a tenuous claim to asymmetry due to that layout.
What's not so well known is that the starboard wings were 4 inches
longer (than the port wings) to compensate for extra weight of
engine. True, that's not very asymmetrical, but the Flyer is lop-
sided none-the-less! :-) Check out this URL for the details:
http://www.first-to-fly.com/History/1903fly.htm "
On 03-06-2001 I got this remark
from Erik Bakker:
"The A-10A
Thunderbolt is also (slightly) asymmetrical. It
was designedaround its primary weapon, the
awesome Avenger cannon in the nose. To accommodate
this gun, the nose landing gear was placed to the left side
of the aircraft. The placement of the barrel of the
cannon is slightly to the
right."
It is true that parts that are
normally centered can be placed slightly out of center. This front
wheel is one of the examples. I also know of a German WWII project
(never left the drawing board), which is sometimes called
asymmetrical because the cockpit was placed of center. It is the
Blohm & Voss Ae 607. But that surely isn't the
most spectacular asymmetrical design of Blohm & Voss. Just go
to www.luft46.com
and go see their other asymmetrical designs: BV
237, BV P111, BV P179 en
BV P 194.01. They all are worth watching. But it
needs to be said that none left the drawing
board.
Christophe Meunier has a site with
real and unreal asymetrical airplanes.
http://cmeunier.chez-alice.fr/Asymm_addition.htm