Sichelflieger (oz15393)


Sichelflieger (oz15393) by Josef Wimmer 1993 - plan thumbnail

About this Plan

Sichelflieger (AKA Sif). Radio control slope soarer model. Flying wing layout. Wingspan 1720 mm.

Direct submission to Outerzone.

Cleanup by RogerB.

Update 5/7/2024: Added article, thanks to Rennfahrer.

Quote (google-translated): "SIF (Sickle plane). An experimental flying wing, by Josef Wimmer.

Motto: Progress is only possible if you intelligently break the rules. Boleslaw Bavlog

It seems to me that the Horten brothers already knew this saying, as they proved with their flying wing designs, which at that time (from 1933) were considered a revolutionary new type of aircraft, that their idea violated the applicable rules of aircraft construction. Bell-shaped lift distribution - well, what a thing! The performance of their designs does not need to be emphasized here, but one thing seems remarkable to me: I read: To conclude the slow flight interpretations, the Horten parabola should be mentioned, an aircraft with a very small surface load of 6 kg/m2, which with a wingspan of 12 m, a curve radius of only 14 m could be flown.

As early as 1911, Alois Wolfm├╝ller, who lived in Munich, applied for a patent for an 'aircraft with sickle-like, wind-slanted wings'. In Russia, in 1924, Tschevanowski built a motorized two-seater as a parabolic aircraft.

Alexander Lippisch also worked with the parabola and built the experimental aircraft 'Delta V' DFS 40 in 1937. Then things went quiet around parabolic flying and the only activity in this species seemed to be noticed by our swallows.

Why is that? I can put it bluntly: the economic thinking of our industrial society and the nonsense that everything has to happen quickly.

Reason: From a purely technical point of view, it is not difficult to create curved wings, i.e. parabolic or sickle shapes, even today using modern materials. The cost of molds, tools, heling and templates is of course much higher than for a straight wing with possible kinks, sweeps and double sweeps. Much higher, which means: more time-consuming and therefore more costly. In addition, there is far less recourse to semi-finished products such as profiles, sheets and other construction elements, since the industry only offers these straight and flat, as desired. Deforming and reshaping these elements is of course more expensive than using them as they are. Trees also grow straight and strips have to be bent; no problem - but too expensive, and besides, wings made of wood, how unfashionable.

Us model airplane pilots? God save us from the many excuses why so many of us really can't build our own and therefore have to buy ready-made standard models.

So we're only left with the swallows and the swifts?

No, there are still some model airplane pilots here and there who haven't forgotten that model flying was always preceded by model building; and that it's no different today if you expect the best from the hobby: the joy of building your own..."

Supplementary file notes



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Sichelflieger (oz15393) by Josef Wimmer 1993 - model pic

  • (oz15393)
    by Josef Wimmer
    from FMT
    August 1993 
    67in span
    Glider R/C
    clean :)
    all formers complete :)
    got article :)
  • Submitted: 16/06/2024
    Filesize: 478KB
    Format: • PDFbitmap
    Credit*: KaoruKiyose, RogerB
    Downloads: 468

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User comments

Have renamed this one now from 'SIF' to 'Sichelflieger'. Although SIF is the title that appeared on the plan drawing, the sub-title from the article of 'Sickle-winged flyer' seems more useful, and will show up better in searches.
SteveWMD - 05/07/2024
In the article it mentions the name of the model in the background (main pic) is "Mr Stringfellow's flying maschine", also from FMT.
SteveWMD - 05/07/2024
blog at:
Pit - 05/07/2024
more on Joseph Wimmer models:
pit - 05/07/2024
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