US3801052A - Sailplane - Google Patents

Sailplane Download PDF

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Publication number
US3801052A
US3801052A US00301805A US3801052DA US3801052A US 3801052 A US3801052 A US 3801052A US 00301805 A US00301805 A US 00301805A US 3801052D A US3801052D A US 3801052DA US 3801052 A US3801052 A US 3801052A
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United States
Prior art keywords
sailplane
central rod
sail
framework
set forth
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Expired - Lifetime
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US00301805A
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English (en)
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A Quercetti
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Individual
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Individual
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    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63H—TOYS, e.g. TOPS, DOLLS, HOOPS OR BUILDING BLOCKS
    • A63H27/00—Toy aircraft; Other flying toys
    • A63H27/08—Kites

Definitions

  • ABSTRACT A sailplane wherein a flexible sail is loosely connected [52] U.S. Cl 244/153 R at its corners to the ends of a rigid framework com- [51] Int. Cl. B64c 31/06 prising a central longitudinal rod and a pair of oblique [58] Field of Search 244/153 R, 154, 155 R, rods directed laterally and backwards, whereby during 244/DIG.
  • This invention relates to a sailplane whose construction is unexpensive and whose performance is good.
  • the sailplanes having stability features and especially aerodynamic efficiency features such as to assure a long lasting flight, an efficacious height elevation by traction effect and a good utilization of the ascending currents encountered, do not lend themselves to economical industrial manufacture.
  • the first object of the invention is to provide a sailplane suitable to be used either as a toy or for sporting objects, for meteorologic observations and for the transport of suspended objects, which due to a particular configuration of its active aerodynamic surfaces presents marked features of longitudinal, transverse and heading stability, together with a remarkably high aerodynamic efficiency, so that its performances are clearly more satisfactory than those of the known analogous sailplanes.
  • Another object of the invention is to provide a sailplane suitable to plane with a good efficiency while still engaged to the tow cable, so that it may switch from the free flight to the towed flight and vice versa, simply by actuating or interrupting the towing action, to permit a control from ground at least concerning the distance from the operator and some simple manipulations, these features being particularly intended to permit the use of the sailplane within a limited space as well as to facilitate its use which, in the versions having a toy character, is also suitable for school-children.
  • a sailplane of the type comprising a framework and a sail formed by a sheet of a flexible material connected at its vertices to said framework, characterized in that said framework comprises a central rod located along a longitudinal central line of the sailplane, a rigid connecting element along said central rod in its front half, and a pair of oblique rods rigidly connected to said connecting element and extending towards the backward section of the sailplane forming an acute angle with respect to said central rod, and in that the sheet of flexible material forming the sail is connected to the ends of said rods forming the framework and its dimensions exceed the framework dimensions so that it is loose or flabby at rest and assumes when flying, due to the effect of the air pressure, a configuration including two forward portions located in front of the oblique rods and having a general positive incidence, and two rear portions located behind the oblique rods, having a general negative incidence and forming a pair of channels which diverge with respect to the longitudinal central rod
  • the plan view shape of the sail substantially derives from a square or a rhombus located with a diagonal along said longitudinal center line, the rear vertex of said square or rhombus being cut off along a line nearly perpendicular to said longitudinal center line, and said oblique lines terminate at the side vertices of said square or rhombus.
  • each of said oblique rods and the rear part of the longitudinal center line is preferably comprised between 40 and (preferably 55) BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a plan view, on a very reduced scaple, of a sailplane according to the invention
  • FIG. 2 is a cross section along line B-E of FIG. I, viewed in the direction of arrow II;
  • FIG. 3 is a cross section along line IIIIIIIII of FIG. 1 and viewed from the rear; FIGS. 2 and 3 showing the sailplane in flight conditions;
  • FIG. 4 illustrates on cross section and in a larger scale the detail of an orientable member connecting the wing ends
  • FIG. 5 illustrates a longitudinal cross section of a member for the coupling of the tow cable
  • FIG. 6 is a view of the front part of the coupling DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
  • the sail of the sailplane is symmetrical with respect to a longitudinal center line a and is delimited by two front sides b, b which extend between the forward end A and the side vertices B,B, by two inclined rear sides c,c extending between the lateral vertices 13,8 and rear vertices C,C, and by a rear transverse side d extending between the rear 'vertices C,C and passing through the after end D of the sail.
  • Each of the right hand and the left hand parts ABCD of the sail which are symmetrical with respect to line a, is subdivided in two portions: 1 the forward and 2 the rear, by an oblique line e extending from a point E, located in the forward half of line a, to the lateral vertex B.
  • lateral vertices B lie in a same plane with the central line a.
  • the sail is formed by a sheet of a substantially flexible material which may preferably be a thin rolled polyester, and cooperates with a substantially rigid framework formed, e.g., by rods of wood or other suitable and relatively light material.
  • a longitudinal rod 3 materializes the longitudinal center line a
  • two oblique bars 4 materialize the oblique lines e and a junction member 5 materializes point E
  • the dimensions of the sail are slightly greater with respect to the lengths of the rods, so that in the rest condition (F IG. 5) the sail is applied loosely to the underside of the framework.
  • the whole lift and resistance effects applied to the sail include pressures which are perpendicular to the same sail and put it in tension with respect to the framework but, due to the greater dimensions of the sail, this assumes an arcuate configuration, with respect to the framework, with the concavity facing downward and, precisely, the forward portions I assume a positive incidence and the rear portions 2 assume a negative incidence and divergent channel shapes with respect to the central rod 3.
  • the aerodynamic efficiency of the sail assembly so formed is remarkably high and, ensures the capability of the sailplane to plane with a stable trim and heading, with a slight gliding angle,in calm air, to rise rapidly by traction effect obtained by means of a cable 9 dragged with respect to the calm air or retained withrespect to the wind, and to keep at height under the effect of even the slightest ascensional currents encountered.
  • the efficiency and the stability of the sailplane may be increased by providing some orientability, relative to the framework, for the wing ends of the sail, so that under the stresses applied by theair during flight, the ends of the sail forward portions displace slightly downward.
  • This displacement is due to the prevalent forces acting on the sail rear portions giving them a negative incidence, and to the fact that this negative incidence is transmitted to the sail forward portions as the effect of the orientability of the wing ends.
  • This causes a displacement of the pressure centers on the sail forward portions and it is thought this is the principal reason of the ascertained increase of stability and aerodynamic efficiency.
  • Blade 8' which is provided with an adhesive layer on its lower face, is an excellent means for the fastening of the connecting members 8-8 onto the wing ends, that is, in correspondence with the lateral vertices of the synthetic material sheet forming the sail.
  • Cap 8 is rotatingly inserted, that is' not forced, onto the end of the corresponding lateral rod 4.
  • the wing ends so sustained with mobility orientate, in flight, as indicated in FIGS.
  • a connecting member 7-7 substantially similar to member 8-8 described, may be opportunely used for the connection of the longitudinal rod 3 to the tail D of the sail, contributing thereby to the forward displacement of the barycenter. ln this case, some elastic flexibility of blade 7 becomes important, as has been ascertained, because it favors particularly the Sailplane stability during towing.
  • an analogous connecting member 6-6 having the blade 6' on the open side of cap 6 instead of the closed side, may be used to connect the sail forward end A to the central rod 3'.
  • the general shape of the sail preferably derives from a square ABFBA located with a diagonal AF along the longitudinal central line a, and from which a triangular rear part CFC has been cut off with a transverse cut d passing through the after point D.
  • the sailplane has been provided with a member for the coupling of the traction cable 9, substantially as represented in FIGS. 5 and 6. It comprises a sleeve shaped part to be firmly connected to the rods located along the median axis a of the framework, and a lower flange 11 which is provided with a plurality of connection pins 12 arranged side by side of one another so that one of them lies on the center line while the others are more or less laterally displaced, to the right hand and left hand respectively.
  • This arrangement permits also improving the behaviour of the sailplane, by the introduction of a wilful] lack of alignment between said centers, in case the sailplane is to be towed, for its lift, along a direction which is transverse to the direction of the wind, namely in conditions of lateral wind.
  • the coupling member 10 must not be allowed to rotate around the center line a, said member is suitably connected to the junction member 5 by means of a rod 3 which is not round, which may be advantageously formed by a structural shape, for example H shaped, of a rigid synthetic material.
  • a rod 3 which is not round, which may be advantageously formed by a structural shape, for example H shaped, of a rigid synthetic material.
  • the longitudinal rod of the framework is formed by three sections, forward 3', median 3" and rear 3, whose extreme sections 3 and 3 are advantageously wood rods having a circular cross section, While the intermediate section is a non circular structural shape of a synthetic material.
  • the length of the wing span being indicated by BB
  • the length from prow to stern AD is about 82% of the wing span
  • the distance AE between the prow and the point from which the oblique lines e start is 15% of the wing span
  • the length of the rear side a' is about 38% of the wing span.
  • the angle BED formed by the oblique lines 2 with respect to the rear portion of the longitudinal center line a is about 55.
  • the distance prow-stern may be preferably comprised between 65% and 90% of the wing span
  • the distance between the prow and the point from which the oblique lines 2 start may be preferably comprised between 10% and 25% of the wing span
  • the length of the rear transverse side may be preferably comprised between 25% and 50% of the wing span
  • the angle BED may be generally and preferably comprised between 40 and 75+.
  • the angles ABC and BAB are not necessarily right angles but they may be generally comprised between 60 and 120, that is, the ideal square ABFB may be replaced by a widened or lengthened rhombus, or generally by a quadrilateral.
  • the rectilinear segments b, c, d, 2 represent the scheme of the sailplane construction, but that in practice they may be replaced by curves or by sinuous or broken lines either for technical or for aesthetical reasons. Therefore, as an example, the forward sides b may present a slightly concave line while the sides c, d may be replaced by a single curve, and lines e may present central sections perpendicular or nearly perpendicular to the central line a. Further, in correspondence of the prow and stem points A, D, the sail may have extensions which are of no efficacy for aerodynamic purposes but serve e.g. to simulate the shape of a cockpit.
  • Rods 3, 4 may be connected one to another by a junction member 5 which presents short tubular branches intended to receive the ends of the rods, in a manner well known eg in the construction of kites.
  • the sailplane does not require a lateral V shape, and hence said junction member may be planar. It must yet be understood that no technical reason prevents one from giving to the sailplane a V configuration if considered preferable, as for example for aesthetical reasons.
  • a sailplane comprising a substantially rigid framework and a flexible sail
  • said framework comprising a central rod extending in the longitudinal direction of the sailplane, along said central rod in the forward portion thereof, a
  • connection member and a pair of oblique rods fixedly connected to said connection member and extending towards the rear portion of the sailplane forming an acute angle with respect to said central longitudinal rod,
  • said sail comprising a sheet of a flexible material having corners connected to the ends of said rods of the framework;
  • said sheet has from edges which are substantially longer than the distances between the forward end of said central rod and the free ends of said oblique rods, and has rear edges which are substantially longer than the distances between the rear end of said central rod and the free ends of said oblique rods whereby said sail is loose on said framework at rest and assumes during flight, due to the effect of air pressure, a configuration including two forward portions located in front of said oblique rods and on the right and the left respectively of the forward portion of said central rod, said forward portions of the sail having a positive aerodynamical incidence, and two rear portions located behind said oblique rods and on the right and the left respectively of the rear portion of said central rod, said rear portions of the sail having a negative aerodynamical incidence, and forming a pair of channels which diverge with respect to said central longitudinal rod of the framework of the sailplane.
  • each connecting cap having a sleeve portion and an extension integral with said sleeve portion
  • a rear connecting cap having a sleeve portion and an extension integral with said sleeve portion, said extension being resiliently flexible and being joined to the flexible sheet forming the sail at the rear end thereof, and the sleeve portion of said rear connecting cap being inserted upon the rear end of said central rod of the framework.

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  • Toys (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
US00301805A 1971-11-16 1972-10-30 Sailplane Expired - Lifetime US3801052A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT70739/71A IT942855B (it) 1971-11-16 1971-11-16 Veleggiatore

Publications (1)

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US3801052A true US3801052A (en) 1974-04-02

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Application Number Title Priority Date Filing Date
US00301805A Expired - Lifetime US3801052A (en) 1971-11-16 1972-10-30 Sailplane

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US (1) US3801052A (show.php)
DE (1) DE2201168A1 (show.php)
ES (1) ES185589Y (show.php)
FR (1) FR2160470B1 (show.php)
GB (1) GB1357058A (show.php)
IT (1) IT942855B (show.php)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2815516A1 (de) * 1978-04-11 1979-10-18 Schenk Spielwaren Franz Spielflugkoerper nach art eines gleitdrachens
US4807832A (en) * 1987-07-16 1989-02-28 Tabor Donald C Two-string delta-style kite with sail curvature control
US4815681A (en) * 1986-11-03 1989-03-28 Crowell Robert L Stunt kite dihedral wing
DE9015092U1 (de) * 1990-11-02 1991-01-17 Schmitz, Raimund, 4100 Duisburg Lenkdrachen
DE4022245A1 (de) * 1990-04-02 1991-10-10 Hoffrei Drachenladen Drachenwe Lenkdrachen
US20030192993A1 (en) * 2001-03-12 2003-10-16 Don Tabor Aircraft kite
US20110072745A1 (en) * 2008-06-12 2011-03-31 Pantelides Chris P Anchoring, splicing and tensioning elongated reinforcement members
US20110197540A1 (en) * 2008-06-12 2011-08-18 Pantelides Chris P Anchoring, splicing and tensioning elongated reinforcement members
WO2011130298A1 (en) * 2010-04-13 2011-10-20 The University Of Utach Research Foundation Sheet and rod attachment apparatus and system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2290724A (en) * 1994-07-01 1996-01-10 Peter Bernard Shaw Luckman A wind propelled model control line aeroplane

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2463135A (en) * 1947-05-29 1949-03-01 Robert F Bach Flying wing kite
US2537560A (en) * 1948-01-29 1951-01-09 George D Wanner Kite
US3018075A (en) * 1958-09-08 1962-01-23 James C Bowers Kite frame assembly
US3276730A (en) * 1964-07-23 1966-10-04 Charles H Cleveland Tailless kite
US3305198A (en) * 1965-08-03 1967-02-21 Jr Harvey A Sellers Glider kite
US3347500A (en) * 1966-06-30 1967-10-17 Alfred E Hartig Kite

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2463135A (en) * 1947-05-29 1949-03-01 Robert F Bach Flying wing kite
US2537560A (en) * 1948-01-29 1951-01-09 George D Wanner Kite
US3018075A (en) * 1958-09-08 1962-01-23 James C Bowers Kite frame assembly
US3276730A (en) * 1964-07-23 1966-10-04 Charles H Cleveland Tailless kite
US3305198A (en) * 1965-08-03 1967-02-21 Jr Harvey A Sellers Glider kite
US3347500A (en) * 1966-06-30 1967-10-17 Alfred E Hartig Kite

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2815516A1 (de) * 1978-04-11 1979-10-18 Schenk Spielwaren Franz Spielflugkoerper nach art eines gleitdrachens
US4815681A (en) * 1986-11-03 1989-03-28 Crowell Robert L Stunt kite dihedral wing
US4807832A (en) * 1987-07-16 1989-02-28 Tabor Donald C Two-string delta-style kite with sail curvature control
DE4022245A1 (de) * 1990-04-02 1991-10-10 Hoffrei Drachenladen Drachenwe Lenkdrachen
DE9015092U1 (de) * 1990-11-02 1991-01-17 Schmitz, Raimund, 4100 Duisburg Lenkdrachen
US6854690B2 (en) * 2001-03-12 2005-02-15 Don Tabor Aircraft kite
US20030192993A1 (en) * 2001-03-12 2003-10-16 Don Tabor Aircraft kite
US20110072745A1 (en) * 2008-06-12 2011-03-31 Pantelides Chris P Anchoring, splicing and tensioning elongated reinforcement members
US20110197540A1 (en) * 2008-06-12 2011-08-18 Pantelides Chris P Anchoring, splicing and tensioning elongated reinforcement members
US8904721B2 (en) 2008-06-12 2014-12-09 University Of Utah Research Foundation Anchoring, splicing and tensioning elongated reinforcement members
US8925279B2 (en) 2008-06-12 2015-01-06 The University Of Utah Research Foundation Anchoring, splicing and tensioning elongated reinforcement members
WO2011130298A1 (en) * 2010-04-13 2011-10-20 The University Of Utach Research Foundation Sheet and rod attachment apparatus and system
US10006477B2 (en) 2010-04-13 2018-06-26 University Of Utah Research Foundation Sheet and rod attachment apparatus and system

Also Published As

Publication number Publication date
DE2201168A1 (de) 1973-05-17
IT942855B (it) 1973-04-02
ES185589U (es) 1973-10-01
ES185589Y (es) 1974-07-01
FR2160470B1 (show.php) 1976-08-20
FR2160470A1 (show.php) 1973-06-29
GB1357058A (en) 1974-06-19

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