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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 »'+.«« 



CSCL 01C 



G3/02 



N7i4-324U0 



Unclas 
4 8550 




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. 



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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