Airplane inventions wing grooves,folding wings, stabilizers
&c

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**Airplanes # 3**

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***NASA Tech Briefs* (Summer 1980)**



**Grooves Reduce Aircraft Drag**

Langley Research Center, Hampton, VA

Aerodynamic drag can be reduced by may small longitudinal
grooves machined in the aircraft skin. Experiments show that
grooves parallel to the airflow reduce drag by 4 to 7 percent.
The reduced drag translates into reduced engine power required
to overcome the drag and ultimately to lower fuel consumption.

The grooves confine incipient bursts of turbulence so that they
cannot expand and disrupt the boundary layer surrounding a
moving craft. Most are V-shaped, but they may take a variety of
dimensions (see figure). For example, they may have rounded or
sharp peaks and symmetrical or asymmetrical cross sections.
Asymmetrical grooves of various cross-sectional geometries may
be arranged in some regular sequences to optimize the
aerodynamic performance.

The most effective dimensions for reducing drag are indicated
in the figure. The dimensions for reducing drag are indicated in
the figure. The dimsnetions are small in comparison with those
tested in previous experiments. In terms of law-of-the-wall
(turbulent flow) coordinates, the heights are less than 30 and
the spacings are less than 40.

This work was done by Michael J. Walsh of Langley Research
Center.

![](grooves.jpg)

**USP # 4,706,910**   
**Combined Riblet and Lebu Drag Reduction
System**   
**(11-17-1987)**   
**WALSH, Michael, et al.**

Classification: - international: B64C21/10; B64C21/00;
(IPC1-7): B64C21/10;- European: B64C21/10   
Abstract --- The invention is a system of flow control devices
which result in reduced skin friction on aerodynamic and
hydrodynamic surfaces. The devices cause a breakup of
large-scale disturbances in the boundary layer of the flow
field. Referring to FIGS. 1 and 2, the riblet device 10 acts to
reduce disturbances near the boundary layer wall by the use of
longitudinal striations forming vee-shaped grooves. These
grooves are dimensional on the order of the wall vortices and
turbulent burst dimensions 31 depicted in FIG. 3. The large-eddy
breakup device 41, depicted in FIGS. 4 and 5, is a small strip
or airfoil which is suspended in the upper region of the
boundary layer. Various physical mechanisms cause a disruption
of the large-scale vortices. The combination of the devices of
this invention result in a substantial reduction in skin
friction drag.

![](us4706-1.jpg)![](us4706-2.jpg)![](us4706-3.jpg)

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***Scientific American* (7 Feb. 1920)**

**Collapsible Wings for Airplanes -- Why
Not?**

There is no doubt that the bird is a better machine than any
that man has made for the purpose of flying, at least so far.
The moment a bird lands its wings are contracted, thereby
enabling the bird to settle quietly on land or sea. It would be
impossible for the bird to shoot straight down and alight on the
chosen spot, were it compelled to do so with its wings fully
extended. Yet it is for that very reason that our powerful
flying amchines so often meet with accidents when landing. In
addition to this, the present ever-rigid wing causes great
inconvenience in connection with the housing with the housing
problem and makes transportation very difficult.

If a gull should attempt to remain floating with wings
stretched out on the sea, it would soon lose its balance and
share the fate of the hydroplanes which in the recent attempt to
cross the ocean had their wings badly battered when compelled to
descend and alight on the rough sea.

We know that wings swinging back on hinges will reduce the
original span of the plane to some extent, and partially solve
this problem. It has remained for someone to design a practical
and properly constructed practical wing for present-day types of
airplanes.

A New York inventor, John  Arthur Weis, has recently come
forward with an ingenious contractable airplane wing, for which
he claims ample strength, reliability and convenience. In fact,
a British manufacturer has begun construction on a machine with
this type of contractable wing. In order to produce a wing that
may be folded automatically and almost instantaneously, this
inventor has replaced the usual rigid spars with a collapsible
construction, similar to the well-known lazy tong telephone
holer but provided with suitable stop locks. In extending the
wing fully the links of the lazy tong construction lie parallel
to each other and are prevented from moving in the opposite
direction by the aforementioned stop locks. At this point the
lazy tong action ceases, and the construction becomes rigid.
Since there are no folds or pockets in the airfoil or wing
surfaces, each section of the wing can be covered independently
with fabric or sheet aluminum. Provisions are made for having
the airfoils airtight, despite the many sectons.

All important and vital members, such as distance bars, ribs,
struts, stabilizers, and so on, remain intact and undisturbed.
When the spars are brought into a straight line, the ailerons
are in position to work on hinges just like those of any present
rigid standard types, according to the inventor. The pilot can
expand or contract the wings by means of a crank or lever in the
cockpit. If desirable, a very simple device in the form of a
little ratchet drum, worm-driven, in conenction with a handwheel
and dial, enables the pilot to apply the necessary tension to
the interplane bracings as soon as the wings are fully extended
and locked.

According to the invnetor, the span of  60-foot machine
can be reduced by the contraction of the wings to about 8 feet.
The extra weight on a two-seater 110-horsepower biplane is about
100 pounds, consequently the loss in velocity is hardly more
than 2 or 3 percent. When the wings are fully contracted the
outlines of the machine resemble somewhat those of a
grasshopper. All in all, the construction is most ingenious, but
one must hesitate to pass on the practicality of this
construction until it has undergone actual application to
full-sized planes.

![](foldwing.jpg)

**US Patent # 1,392,669**   
**Expansible and Contrable Structure**

![](us1392-1.jpg)![](us1392-3.jpg)  
![](us1427-4.jpg)

**US Patent # 1,427,669**   
**Airplane**

![](us1427-1.jpg)![](us1427-2.jpg)

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**Vicompte de Rouge**

**Stabilizer**

***Popular Science* (April 1934)**

**"Vanes On Mast Keep Glider Level"**

Successful in its first test flights, a glider with an
unconventional stabilizing device has been introduced by a
French inventor. The stabilizer, carried on a mast above the
wing, is used to correct any tendency to pitch forward or
sideslip in flight. Its two hinged vanes are so wired that they
may be folded flat or spread sideways by a control in the hands
of the pilot, and thus stabilize the plane.

![](0vico1.gif)

***Popular Science* (May 1932)**

**"Something New For Flying"**

Below, Vicomte de Rouge, a French engineer and inventor, seated
in his strange tailless plane. Opening the hexagonal control on
the mast directs the plane upward and closing it guides it down.
The rudders on the wing tips are used to steer the queer craft.

![](0vico2.gif)  
 

**French Patent # 42286E**

![](fr42286-1.jpg)![](fr42286-2.jpg)  
![](fr42286-3.jpg)

**US Patent # 1,919,831**   
**Stabilizing Device for Airplanes**

![](us1919-1.jpg)

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