Asymmetrical airplanes

Weird airplane designs

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:

  1. Three seats
  2. Good all-round view
  3. 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.

 

BV 141

 

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.

 

Forces on a conventional airplane

 

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.

 

Forces on the BV 141

 

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.

Ares of Scales Composites (Click picture to get to site of Scaled Composites) (permission to use picture by Kaye LeFebvre of Scaled Composites Inc.)

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.

Thanks to Brandon Inks i can use this very nice picture of the Boomerang designed by Burt Rutan.

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