NASA TECHNICAL TRANSLATION
NASA TT F-15920
A NEW TYPE OF SAIL PLANE
R. Platz
Translation of "Zeitschrift fuer Flugtechnik
u.Motcrluftschiffahrt," Volume 15, Number 1^2,
26 January 1924, pp. 1-2.
/Hi^i-TT-P-15920) A NE8 TYPE OF SAli
PLASE (Techtran Corp.) 7 p hc »'+.««
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NATIONAL AERONAUTICS AND SPACE Al
WASHINGTON, D. C. 20546 SEP'
TRATION
:MBER 1974
STANDARD TITLE PAGE
1. Report No.
NASA TT F- 15920
2. Gavernment Acctstion No.
3. Recipient's CQlalog No.
4, Title 4nd Subtitle
A NEW TYPE OF SAIL PLANE
5, Report Dole
SEPTEMBER 1974
6, Parferming Orgonriolion Code
7. Aolhor(j)
R. Platz
B. Parforming Orgoniiaiien Report No.
10. Work Unit No.
9. Performirtg Organization Noma ond Addreis
Techtran Corporation
P.O. Box 729, Glen Burnie, Md. 21061
1 1 . Contract or Grant No.
NASW-2485
13. Typo of Report and Period Covered
Translation
12. Sponioring Agency Nome arid Address
National Aeronautics and Space Administration
Washington, D. C. 20546
14. Spontortng Agoncy Cod*
15. Supplomentory Notes
Translation of "Zeitschrift fuer Flugtechnik u.Motorluftschiffahrt/'
Volume 15, Number 1 5 2, 26 January 1924, pp. 1-2.
1&. Abitract
This is a report from a newspaper article on' some early attempts
to construct sail planes. The authors are examining some new designs
and new concepts for the flight control of such craft. They note that
the prospects for the construction of a light weight, durable, easily
disassembled plane of this type are good.
17. Key Word* (SelBCted by Author(s))
18. Distribution Statement
Unclassified-Unlimited
19. Security Claiiif. (of this report)
Unclassified
20. Security Clat*l{. (of this poge)
Unclassified
21. No. of Page*
6
22. Price
11
NASA-HQ
A NEW TYPE OF SAIL PLANE ^
R. Platz
The great interest, which has been exhibited in the sport of sail planes, [V
has given rise to attempts to construct a sail plane that even in these times
can be purchased by any and all lovers of the sport. The following are pre-
requisites for this:
1. Very low retail price; not appreciably more than the cost of a good
bicycle.
2. Pieces that can be put together in a relatively small package so that
it can be transported even in an automobile.
3. Durability of all points so that it will not be harmed when seized with
force or when struck.
4. Quick and easy assembly.
5. All parts must be easily replaced or substituted.
6. The sail plane must be able to be carried by one man.
Until now these conditions had not been fulfilled, in the making of sail
planes. We have here, then, a real advance.
The basic concept was inspired by the memory of a sail on a sailboat rigged
up as a sloop; by proper adjustment of the sails and proper agreement of the
center of gravity of the sail with the lateral center of gravity, one can sail
for a long time without steering: the sails are "stable". A boat positioned
in this manner can be guided to a limited extent by hauling in or letting loose
the jib.
Let us now take two such sails and place their surfaces along side one
another. We shall view the lateral center of gravity as the critical. We shall
^This study had already gone to the editorial staff on' February 16, 1973, at the
wish of the author, it is now being made available] to the public for the first time.
*Numbers in the margin indicate pagination in the foreign text.
1
turn 90° about the longitudinal axis. From this, as one can see from Figure 1,
we have a sail plane with which we can fly straight ahead and can adjust for
ascent or descent. In keeping with the intended simplicity and low purchase
price J we should seek to avoid any other steering and further mechanisms. We
need to test to see if what we have already proposed provides sufficient steering
as it is. Transverse stability could be achieved through the proper V-positioning
of the crossbeams, or masts. Then, the only thing missing is the side-rudder.
_ The jibs can assume this function,
A paper model, as Figure 2
shows, served as the first model.
It is weighed down with a paper
clip. The transverse stability,
because of the V-positioning, is
good. The rudders for ascent and
descent work fine. Completely
adequate steering toward the right
side was achieved by activating
the right jib. This was the case
at all wind speeds and even when
By activating the left jib, the
Sailboat L .■ i,- •/ '' '4: -^ Sail planeL- .-Ci^?,
■:^- ■:'■•?■
Lateral center" of gravity^
[Direction of travel/flight!'
1»
■^Center of gravity t? -;: - ci^
;te.ff
X\
>■ ;[ Direction of travel/flight i
■ .i rM ii n-^ ., , ~ . °
Figure 1.
we let the paper model fall perpendicularly,
same results were attained on that side.
Now the final form was decided on and in four hours of work a model 1.3
meters wide and 0.4 square meters in surface was fabricated. The first trial
flights took place in dunes of about 6 to 8 meters in height at the beginning
of November, 1922. The lack of wind on the first day made it unsuitable for
flying. The precise positioning of the jib and of the weight, since it consisted
of a vice, whose position could be varied, could be worked out that much the
better. On the following day, the first success was achieved. The "model"
'sailed" in a light wind with a surface weight of 2 1/2 kilograms per square meter. /2_
Repeatedly, it was able to ascend. Headed into the wind, it moved along the
ridge of the dune without loss of elevation, just as this has so often been
observed and described of seagulls. From this model it was now to apparent that
all the conditions previously mentioned could be met. A large-scale plane could
present difficulties only with non-rigid wings or a (the wings') changeable profile.
2
Figure 2.
To study this question, which was now of
primary importance, another model was built in a
few hours. It had a span of 2.5 meters and a
surface of 1.3 square meters. In test runs, it
exhibited no appreciable variation from the
performance of the smaller model.
On the basis of these findings, a sail plane
of about 16 square meters surface was constructed
in a few days .
It consists of a curved skid made of steel
pipe. The rear mast of wood is inserted into its back end. This mast has a
soldered joint on either side for the insertion of the masts, which likewise
are of wood. The other main parts are the "main sail," which is sewed together,
and the jibs, their necessary mountings, and three tin fittings.
The "rotary parts" consist of but a single screw, which holds the jibs
together, jibs that can be turned forward.
In ten minutes the whole plane can be tied up, ready for carrying. It has
the following dimensions: 3.3 x 0.35 x 0.25 meters and weighs about 40 kilograms.
A means of transporting it may be seen in Figure 3.
One man can put the plane
together for sailing in fifteen
minutes.
As with the smaller models,
tests were usually run in a
mild wind and with a small
weight. Flexing of the sails,
steering, and landing worked
well, just as with the models.
Further tests in the
following days were undertaken
in strong winds. A sand ballast
Figure 3.
of up to 7S kilograms was used on dunes 25 meters high. About fifty test flights
were undertaken without a pilot and with the rudder fixed. Often the sail plane
landed in the sea or behind the dunes without the slightest damage.
The next tests were carried out with pilots. The plane was held by four
ropes and began with a pilot weighing 55 kilograms. Ten more pilots, weighing
up to 100 kilograms, established that the rudder for ascending is easy to operate.
Because the cliffs of the dunces were, In places, vertical, it was too dangerous
to cut the plane losse without further practice.
The first free flight took place on the next flying day in February, 1923,
in a mild wind and from a 10 to 12 meter high dune.
Now tacking must be tried in the dunes, which really are not suited to this,
and the testing may be considered concluded.
Even though the aerodynamic qualities of this sail plane are not the same
as those of a well-rigged sail plane, still, the advantages noted at the beginning
are of great significance.
It will be interesting to hear the views and opinions of experts and of
practitioners of plane sailing concerning the problem we have described and this
first attempt at a solution.
/''-f*..
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Figure 5.
Translated for the National Aeronautics and Space Administration under contract
No, NASW-24S5 by Techtran Corporation, P. 0, Box 729, Glen Buxnie, Maryland,
21061, translator: Dr. Guy Hollyday
