CA1059487A - Minimum weight and high strength framed structure - Google Patents
Minimum weight and high strength framed structureInfo
- Publication number
- CA1059487A CA1059487A CA252,815A CA252815A CA1059487A CA 1059487 A CA1059487 A CA 1059487A CA 252815 A CA252815 A CA 252815A CA 1059487 A CA1059487 A CA 1059487A
- Authority
- CA
- Canada
- Prior art keywords
- control
- plastic
- framework
- mold
- aircraft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229920003023 plastic Polymers 0.000 claims abstract description 33
- 239000004033 plastic Substances 0.000 claims abstract description 31
- 239000003381 stabilizer Substances 0.000 claims abstract description 14
- 239000011248 coating agent Substances 0.000 claims abstract description 11
- 238000000576 coating method Methods 0.000 claims abstract description 11
- 239000000835 fiber Substances 0.000 claims abstract description 9
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910052796 boron Inorganic materials 0.000 claims abstract description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 4
- 239000010439 graphite Substances 0.000 claims abstract description 4
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 4
- 239000011777 magnesium Substances 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 22
- 238000011065 in-situ storage Methods 0.000 claims description 16
- 239000003822 epoxy resin Substances 0.000 claims description 14
- 229920000647 polyepoxide Polymers 0.000 claims description 14
- 239000006260 foam Substances 0.000 claims description 12
- 239000008261 styrofoam Substances 0.000 claims description 7
- 229920006328 Styrofoam Polymers 0.000 claims description 6
- 239000004744 fabric Substances 0.000 claims description 6
- 239000003365 glass fiber Substances 0.000 claims description 6
- 229910000831 Steel Inorganic materials 0.000 claims description 5
- 229920005989 resin Polymers 0.000 claims description 5
- 239000011347 resin Substances 0.000 claims description 5
- 239000010959 steel Substances 0.000 claims description 5
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims description 4
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 claims description 4
- 238000005470 impregnation Methods 0.000 claims description 4
- 229920001228 polyisocyanate Polymers 0.000 claims description 4
- 239000005056 polyisocyanate Substances 0.000 claims description 4
- 229920001577 copolymer Polymers 0.000 claims description 3
- 229920000271 Kevlar® Polymers 0.000 claims description 2
- 229910000861 Mg alloy Inorganic materials 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 239000004761 kevlar Substances 0.000 claims description 2
- 239000002984 plastic foam Substances 0.000 claims description 2
- 239000000088 plastic resin Substances 0.000 claims description 2
- 239000004814 polyurethane Substances 0.000 claims description 2
- 229910000838 Al alloy Inorganic materials 0.000 claims 1
- 238000005187 foaming Methods 0.000 claims 1
- 229910052751 metal Inorganic materials 0.000 abstract description 4
- 239000002184 metal Substances 0.000 abstract description 4
- 238000010276 construction Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 229920002466 Dynel Polymers 0.000 description 5
- 239000002131 composite material Substances 0.000 description 5
- 235000011890 sandwich Nutrition 0.000 description 5
- 239000004593 Epoxy Substances 0.000 description 3
- 239000006096 absorbing agent Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000035939 shock Effects 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 2
- 239000006223 plastic coating Substances 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000011496 polyurethane foam Substances 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- GHPYJLCQYMAXGG-WCCKRBBISA-N (2R)-2-amino-3-(2-boronoethylsulfanyl)propanoic acid hydrochloride Chemical compound Cl.N[C@@H](CSCCB(O)O)C(O)=O GHPYJLCQYMAXGG-WCCKRBBISA-N 0.000 description 1
- 229920002972 Acrylic fiber Polymers 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 229920005830 Polyurethane Foam Polymers 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 210000003298 dental enamel Anatomy 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 229920006335 epoxy glue Polymers 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000004021 metal welding Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/12—Incorporating or moulding on preformed parts, e.g. inserts or reinforcements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
- B64C1/06—Frames; Stringers; Longerons ; Fuselage sections
- B64C1/061—Frames
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Aviation & Aerospace Engineering (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Light-weight aircraft are provided by a light-weight tubular frame-work of metal, e.g. aluminum or magnesium or boron or graphite fibers, includingcables or rods for aileron control, for spoiler aileron control, for flap control, or horizontal stabilizer control, for vertical stabilizer control, for retractorcontrol, for steering control and for landing gear assembly control in selected ones thereof and a foamed plastic adhered to the framework with a smooth hard coating over the foamed plastic. The controls are provided in a protected environment and are placed within the tubular superstructure to provide a more simplified unitary structure. The foamed plastic and the smoother hard coating may be built up in layers at certain stress points.
Light-weight aircraft are provided by a light-weight tubular frame-work of metal, e.g. aluminum or magnesium or boron or graphite fibers, includingcables or rods for aileron control, for spoiler aileron control, for flap control, or horizontal stabilizer control, for vertical stabilizer control, for retractorcontrol, for steering control and for landing gear assembly control in selected ones thereof and a foamed plastic adhered to the framework with a smooth hard coating over the foamed plastic. The controls are provided in a protected environment and are placed within the tubular superstructure to provide a more simplified unitary structure. The foamed plastic and the smoother hard coating may be built up in layers at certain stress points.
Description
~05~4~7 '' This invention relates to minimum weight, high strength structures. More specifically, it relates to a method for constructing a rapidly assembled, high strength, and light-weight airplane.
Conventional aircraft construction, while it may provide optimization between low weight and high strength, suffers tBe disadvan-tage of being highly labour intensive. In other words, a significant part of the cost is labour, and a major portion of such labour costs are for metal welding, bending and riveting. Thus, Canadian Patent No.
233,368 issued August 7, 1923 to G.S. Carr provides a production line technique for producing a fuselage embodying longerons comprising steel tubing rectangular in crogs-section, each longeron being composed of a plurality of sections having varying diameters welded together and having a telescoping ~oint, the larger section being reduced ad~acent to the ~oint to provide a tight fit.
Canadian Patent No. 291,474 issued July 23, 1929 to B. Bart provides a production line procedure for forming thin steel, hollow metallic reinforced structural units by a number of steps involving the use of formers and electrolytic deposition to provide an homogeneous continuous~ tllin film of metal over a skeletal framework.
Canadian Patent No. 305,131 issued October 28, 1930 to the Boeing Aircraft of Canada Ltd. provides a production line procedure for providing a metallic framework for aircraft. The framework includes a series of structural members and end ~oints for securely fastening the tubular members in end-to-end, parallel or angular relatlonship.
Canadian Patent No. 444,917 issued November 11, 1947 to A.A.
Kucher provideg a production line procedure for forming a composite wall.
The composite wall includes a grill having a mesh of substantial depth.
On the back of the grill is a hardened plastic coating, while on the other face of the grill is another hardened plastic coating, also bonded to the first coating.
Canadian Patent No. 928,696 issued June 19, 1973 to United Aircraft Corporation provides a production line procedure for forming an - 1 - ~ ..
. ., ~487 elongated composite stringer for reinforcing an aircraft fuselage. The stringer includes a plurality of tapes extending longitudinally, each consisting of an epoxy matrix having boron filaments embedded therein running lengthwise of the tape. Cross-direction plies of fiberglass scrim are provided on both sides of the intermediate boron filament tapes.
Aircraft made up of a "sandwich" of light-weight, but strong material, have now been provided. One such aircraft, known as the "RR-l" uses, as a basic material of construction, a foam/fabric~epoxy resin sandwich. In its construction, foam, preferably polyurethane foam, is formed into the desired shape; then a sheet of Dynel fabric is spread over the foam. Epoxy resin is then spread over the Dynel, bond-ing everything together in a light, strong sandwich structure. (Dynel is the Trade Mark of Union Carbide for a copolymer of vinyl chloride and acrylonitrile).
However, this structure, for aircraft, suffers the deficiency that the basic load-carrying structure, i.e. wing spars, empennage spars and most of the fuselage are made of wood. Moreover, the control cables are labouriously and awkwardly installed after virtual completion of the ,~
aircraft.
Moreover, there ls an alrcraft known as El Grlngo whlch has a tubular alrframe and wing spars. Styrofoam sections are individually cut to shape and glued to the airframe and between the wing spars. The styrofoam is covered with Dynel cloth and epoxy resin, and is painted with acrylic enamel.
While such aircraft is of goot design, it suffers the disadvan- -tage that shaping of the fuselage and wings to achieve the required symmetry is time-consuming. Because not all the foam is bonded to the metal, the strength of the composite is lower than it might otherwise be and each section of styrofoam must be individually cut and formed to provide an acceptably smooth exterior and to maintain symmetry. Also, the control rods and/or cables are installed after virtual completion .. . .
. . . :. :.
`~ ~059487 .
of the alrcraft.
~, It would be advantageous to provide such an aircraft in which the excess weight resulting from the use of wood as a load-carrying structure ' would be minimized or even avoided. Furthermore, the difficult and labour lnten~lve task of cutting and shaping all the foam sections should be avoided.
It would also be desirable to have the control rods and/or cables accurately and easily placed within the superstructure during the construction of the S actual superstructure. It would also be an advantage to have the foam cast about the frame so that the structure is symmetrical and integral. r t 8y one broad aspect of this invention, the process is provided for the formation of minimum weight, high strength aircraft, the process comprising:
forming a framework for the desired shape with light-weight, structural tubes of metal or fiber epoxy composites; providing cables or rods for aileron control, for spoiler aileron control, for flap control, for horizontal stabilizer control, for vertical stabilizer control, for retractor control, for steering control ' snd for landing gear assembly control within selected ones of said tubular members;
!~ provlded at least a portion of the exterior surface of the aircraft of approximately or exactly the desired shape by foamlng a plastic in situ about a combination ofuch framework and a mold; sepsrating the molded aircraft from the mold; and ~: 20 applying a flnal costing to the molded aircraft. i~
,~ By one preferred variant thereof, the mold is an external mold, and wherein the steps comprise: placing the framework in a mold of approximately or exactly the desired shape; providing a foamet in situ plastic around and adhered to at least part of the framework, and contacting the interior surface of the mold 90 as to conform generally to the configuration of the mold; and removing i. the molded structure from the mold.
` By another variant, the mold is a hollow mandrel.
By another variant, the mold is of approximately the final shape requlred for the molded structure, and including the additional step of manuallyconfiguring the molded product to the final shape required for the molded structure.
~ ~ - 3 ~ ~ ~ ~ ~ r . ,. A . . "
1`: 1 ~' . , . ~,., ., t; , - -'~'" '"' '' ' . ' ~' `"'' ' 'i '' '`' ~' ` ' '''` '' ~os~s7 By another variant, the entire foamed structure is provided by the ~-foamed in situ plastic.
v By still another varicint, selected areas of the Framework are fllled wlth a preformed plastic foam.
; .
~ By a further variant, at least one of additional foam and layers ;
~!,' of glass fil).rs and resin are deposited at stress points of the fuselage.
By yet a further variant, the wing is formed by multi-layers of foamed plastic and epoxy resin.
By two other variants, the final coating may be applied by means of a first coating of gla~s fibers followed by an impregnation of the glass fibers vlth a resin; or it may be applied by means of a first coating of a fabric formed of a copolymer of vinyl chloride and acrylonitrile, followed by an impregnation wlth an epoxy resin.
, By a further variant, the foamed in situ plastic is molded as a -skin around at least a part of the framework, to provide a substantially hollow core.
By another aspect of this invention, a minimum weight high strength Ircraft structure is provided comprising: a framework of tubular members;
cablo~ or rods for aileron control, for sroiler aileron control, for flap control, for horlzontal stabilizer control, for vertical stabilizer control, for retractor ~t~
control, for ~teering control and for landing gear assembly control withln selected on-s of sJid tubular members; foamed in situ plastic polded around at least a part of said framework to provide a structure of the requlred shape; and a smooth ~kln over the shaped, foamed in situ plastic.
By variants thereof, the tubes may be for~ed of aluminum or an alumlnum alloy, of magnesium or a magnesium alloy, of steel, or of graphite or ~, boron fibers.
By stlll other variants, the plastlc may be polyurethane, styrofoam $;
or foamable hydrophilic polyisocyanate.
~, By still other variants, the skin may be epoxy resin impregnated ~`1 iE3~.
~ - 3a -, ! ~ , ~,:,; ' ' ' '' ''` , J
' ~: '. . . 1: 1 . .
.'~ ' ' ~' - :
.''~,,~' . , ' ' '" ,, ~Q5~,~87 .
- glass fibers, or epoxy resin impr~nated vinyl ~l~loride/~crylonitrile fibers or Kevlar.
The foamed plastic, whether it be prefoamed pl~stic or foamed in ltu plastic c~n be any of the conventional such foams. Exam~les include poly-r~;; urethane and styrofoam. Another particularly preferred foamed plastic is the '`-', foamable hydrophilic polyisocyanate known by the Trade Mark of Hypol (by W.R.
". :
Crace ~ Co.).
The skin covering the foamèd plastic or foamed in situ plastic may 1,.:, ~
'~: be sny suitable such covering. One type is resin impregnated g]nss fibers.
Another ls Dynel fabric to which epoxy resin has been applied.
In the accompanying drawings, Figure l is a plan view of the tubular framework of one fuselage of an aircraft;
' Figure 2 is a plan view of the finished aircraft derived from the ',h fuselage of Figure l;
,'~r, .. :
,~ Flgure 3 is a front elevational view of the tubular framework of the fuselage of the aircraft of Figure l;
~;' Figure 4 18 a front elevational view of the finished aircraft derived from the fuselage of Figure 3, similar to Figure 2;
Flgure 5 ls a section along line V-V of Figure l; and ;, Figure 6 is a section along line VI-VI of Figure 2.
... .
~' As seen in Figures 1 and 3, the general configur;lLion is similar .~, ~ .
'~ to a tricycle/go-cart hybrid with a tail and with an engine .. ~ , . . .
!r ' ;' ~ ' ., .. . .
~ .
~t~ .
~ , _ 4 _ ;`.' `' ' ' ''' . .
~r_, ' , , ' ' , ., , - . ,,,' ,',,,, ~' ' ' '. , - . - :,' , '~ ~ 1()59487 mounted on the front thereof. Thus~ the framework of the aircraft 10 of one embodiment of this invention includes a fuselage framework 20, front P' wing framework 120 and rear wing framework 220. To facilitate home-built construction, the framework preferably makes use of elbows, tees and epoxy glue or even brazing techniques in order to minimize welding.
The material for the framework may be aluminum, boron, steel o-r magnesium;
~: or graphite fibers in an epoxy matrix. The fuselage framework 20 includes a main framework composed of longitudinally extending, rearward-ly converging left and right spars 21, transversely extending, parallel, 10 - upper and lower forward ribs 22, a rear rib 23 and vertically extending connecting beams 24, all interconnected by elbow connectors 25 and tee connectors 30.
! Superposed on the framework 26 is a cockpit framework 31 also of generally rectangular parallelepiped configuration. Cockpit frame-work 31 also includes a pair of longirudinally extending parallel left and right ribs 32, transversely extending parallel upper and lower ribs l ;
~- 33 and vertically extending beams 34, all interconnected by elbow connec-. tors 25 and tee connectors 30.
One configuration of the wing is shown in Figure 6, to be des-crlbet hereinafter. Furthermore, the wing may be a layered foam/epoxy resin sandwich. During the manufacture thereof, rear flap control tube ~ 122, and transversely spaced-apart aileron control tubes 121 are provided.
d~`
~i~ Two pairs of port flap control hinges and two pairs of starboard flap control hinges 124, and two pairs of port and starboard spoiler aileron control hinges 125 are also provided. A landing gear support beam 128 ~ is provided and depending therefrom and from main spar 126 are a port and '~. a starboard landing gear assembly 129. Landing gear assembly includes a shock absorber mechanism 130, and a wheel 132 freely rotatable in axle .
; 133 extending fror.~ the lower end of shock absorber mechanism 130. The wheels are provided with aerodynamic boots 134 which reduce air resis-tance in the retracted position.
The rear wing structure 220 in Figures 1 and 6 is similar to ~?
't,`~:
';;
~ ~ - 5 -:: :
~ .
~;
lQ59487 ?
, , z the main win~ and includes a rear, vertical stabilizer rotatable control ~"", ~;~! tube 222 and a frame tube 224 which adds to the center section strength, as well as a pair of port and starboard hinges 223.
- Pro~ecting upwardly at the rear of the fuselage 20 to support , the rear wing is a rudder framework 250 including a pair of spaced-apart vertical spars 251 and a pair of spaced-apart horizontal t. ~.:
interconnected to each other and to the fuselage at longitudinal spar 234.
Projecting downwardly at the nose of the fuselage 20 is a steerable and retractable nosewheel assembly 275 including a shock absorber assembly 276, a wheel yoke frame 277 and a wheel 278 freely rotatably mounted on an axle 279 between the forks 280 of the wheel yoke 277. , ~' It will be observed that nose wheel 275 assembly is secured ;~i to a cross-beam 28 within which are disposed the retractor control s, cables and/or rods and the steering control cables and/or rods (not :c shown). These cables and/or rods run in the fuselage framework 21 to controls (not shown) in the cockpit 31.
Control cables and/or rods for the landing gear assemblies 127 ~`~ 20 ure dlsposed within transverse tubular rib 128 and terminate in controls in the cockpit 31.
The flap control tube 122 is rotatable to control the flaps.
Similarly, spoiler aileron control tube 123 is also rotatable to control the spoiler aileron. These tubes are provided with operation means which terminate in controls in the cockpit 31.
ij; The horizontal stabilizer is operated by a push rod inside a longitudinally extending vertical stabilizer control spar 2~.
The vertical stabilizer control for the rudder is provided by cables running inside the rearwardly extending ribs 21. The controls ;
all terminate in the cockpit 31.
Fi~ure 6 shows the construction of a typical wing, spoiler and associated tubular supports and hinge. The hinge 125 includes fixed '' ~ ~Q59487 r .
~" "
,.
tube 121 (whi~h may be tube 221), tube 123 and tube 122. Spoiler 119 is shown deployed. Rotation is achieved by either sleeve, or bearing means, and is achieved for the fla~s about tube 122 and for the spoiler r ~" 119 about tube 123.
Once the framework 10 has been assembled, thc~ molding procedure takes place. The framework is placed in a suitably shaped mold. Because the fuselage is so large, sectional molds may be used. It is necessary also to provide an inner mandrel, e.g. an inflatable upper mandrel, to provide a hollow fuselage to minimize the amount of foamed in situ ~ plastic required.
p;. As mentioned before, the foamed-on plastic could be sprayed over the framework rather than using an external mold.
Similarly, the wings and rudder may be formed the same way, although the need for a hollow internal mandrel is not so necessary.
In addition, the wings and rudder can be formed as multilayered sand-wiches of foamed plastic epoxy resin. However, even in such small parts, the exact shape i8 not required for the mold. Wing roots, tops, fillets and ~oints can be exquisitely faired to the desired shape at will with .~, . .
sandpaper.
Moreover, for larger areas, part of the plastic may be provided by preformed sheets which are secured to the framework, and to which the foamed in situ plastic adheres .f~ _ ~p, Once the plastic has been shaped to the exact shape, it is covered with a protective skin.
As mentioned before, the foamed in situ plastic can be of any of the conventional such foams. Exmaples include polyurethane and styro-foam. Another particularly preferred polyisocyanate is known by the Trade Mark of Hypol (of W.R. Grace ~ Co.).
An example of a wing section is shown in Figure 6. The frame-work includes tubes 121, 122, 123 ~oined by plate 130. The foamed in .
~` situ plastic 131 surrounds the framework and is shaped to the proper .
.
:~
. ,, ' ~. ' ' ' , .
lOS9487 aerodynamic form. The skln 132 covers the foam 131.
This provides a fnished aircraft as shown in Figures 2 ant 4 including a fuselage 420, front wing 421, flaps 422, rear wing 423, stablll~er 424, tnll 425, and rudder 426. A preformed acrylic plastic canopy 427 covers the cockplt 428. Conventional means are provided for retracting the wheels into the open area o~ the flaps.
Conventional aircraft construction, while it may provide optimization between low weight and high strength, suffers tBe disadvan-tage of being highly labour intensive. In other words, a significant part of the cost is labour, and a major portion of such labour costs are for metal welding, bending and riveting. Thus, Canadian Patent No.
233,368 issued August 7, 1923 to G.S. Carr provides a production line technique for producing a fuselage embodying longerons comprising steel tubing rectangular in crogs-section, each longeron being composed of a plurality of sections having varying diameters welded together and having a telescoping ~oint, the larger section being reduced ad~acent to the ~oint to provide a tight fit.
Canadian Patent No. 291,474 issued July 23, 1929 to B. Bart provides a production line procedure for forming thin steel, hollow metallic reinforced structural units by a number of steps involving the use of formers and electrolytic deposition to provide an homogeneous continuous~ tllin film of metal over a skeletal framework.
Canadian Patent No. 305,131 issued October 28, 1930 to the Boeing Aircraft of Canada Ltd. provides a production line procedure for providing a metallic framework for aircraft. The framework includes a series of structural members and end ~oints for securely fastening the tubular members in end-to-end, parallel or angular relatlonship.
Canadian Patent No. 444,917 issued November 11, 1947 to A.A.
Kucher provideg a production line procedure for forming a composite wall.
The composite wall includes a grill having a mesh of substantial depth.
On the back of the grill is a hardened plastic coating, while on the other face of the grill is another hardened plastic coating, also bonded to the first coating.
Canadian Patent No. 928,696 issued June 19, 1973 to United Aircraft Corporation provides a production line procedure for forming an - 1 - ~ ..
. ., ~487 elongated composite stringer for reinforcing an aircraft fuselage. The stringer includes a plurality of tapes extending longitudinally, each consisting of an epoxy matrix having boron filaments embedded therein running lengthwise of the tape. Cross-direction plies of fiberglass scrim are provided on both sides of the intermediate boron filament tapes.
Aircraft made up of a "sandwich" of light-weight, but strong material, have now been provided. One such aircraft, known as the "RR-l" uses, as a basic material of construction, a foam/fabric~epoxy resin sandwich. In its construction, foam, preferably polyurethane foam, is formed into the desired shape; then a sheet of Dynel fabric is spread over the foam. Epoxy resin is then spread over the Dynel, bond-ing everything together in a light, strong sandwich structure. (Dynel is the Trade Mark of Union Carbide for a copolymer of vinyl chloride and acrylonitrile).
However, this structure, for aircraft, suffers the deficiency that the basic load-carrying structure, i.e. wing spars, empennage spars and most of the fuselage are made of wood. Moreover, the control cables are labouriously and awkwardly installed after virtual completion of the ,~
aircraft.
Moreover, there ls an alrcraft known as El Grlngo whlch has a tubular alrframe and wing spars. Styrofoam sections are individually cut to shape and glued to the airframe and between the wing spars. The styrofoam is covered with Dynel cloth and epoxy resin, and is painted with acrylic enamel.
While such aircraft is of goot design, it suffers the disadvan- -tage that shaping of the fuselage and wings to achieve the required symmetry is time-consuming. Because not all the foam is bonded to the metal, the strength of the composite is lower than it might otherwise be and each section of styrofoam must be individually cut and formed to provide an acceptably smooth exterior and to maintain symmetry. Also, the control rods and/or cables are installed after virtual completion .. . .
. . . :. :.
`~ ~059487 .
of the alrcraft.
~, It would be advantageous to provide such an aircraft in which the excess weight resulting from the use of wood as a load-carrying structure ' would be minimized or even avoided. Furthermore, the difficult and labour lnten~lve task of cutting and shaping all the foam sections should be avoided.
It would also be desirable to have the control rods and/or cables accurately and easily placed within the superstructure during the construction of the S actual superstructure. It would also be an advantage to have the foam cast about the frame so that the structure is symmetrical and integral. r t 8y one broad aspect of this invention, the process is provided for the formation of minimum weight, high strength aircraft, the process comprising:
forming a framework for the desired shape with light-weight, structural tubes of metal or fiber epoxy composites; providing cables or rods for aileron control, for spoiler aileron control, for flap control, for horizontal stabilizer control, for vertical stabilizer control, for retractor control, for steering control ' snd for landing gear assembly control within selected ones of said tubular members;
!~ provlded at least a portion of the exterior surface of the aircraft of approximately or exactly the desired shape by foamlng a plastic in situ about a combination ofuch framework and a mold; sepsrating the molded aircraft from the mold; and ~: 20 applying a flnal costing to the molded aircraft. i~
,~ By one preferred variant thereof, the mold is an external mold, and wherein the steps comprise: placing the framework in a mold of approximately or exactly the desired shape; providing a foamet in situ plastic around and adhered to at least part of the framework, and contacting the interior surface of the mold 90 as to conform generally to the configuration of the mold; and removing i. the molded structure from the mold.
` By another variant, the mold is a hollow mandrel.
By another variant, the mold is of approximately the final shape requlred for the molded structure, and including the additional step of manuallyconfiguring the molded product to the final shape required for the molded structure.
~ ~ - 3 ~ ~ ~ ~ ~ r . ,. A . . "
1`: 1 ~' . , . ~,., ., t; , - -'~'" '"' '' ' . ' ~' `"'' ' 'i '' '`' ~' ` ' '''` '' ~os~s7 By another variant, the entire foamed structure is provided by the ~-foamed in situ plastic.
v By still another varicint, selected areas of the Framework are fllled wlth a preformed plastic foam.
; .
~ By a further variant, at least one of additional foam and layers ;
~!,' of glass fil).rs and resin are deposited at stress points of the fuselage.
By yet a further variant, the wing is formed by multi-layers of foamed plastic and epoxy resin.
By two other variants, the final coating may be applied by means of a first coating of gla~s fibers followed by an impregnation of the glass fibers vlth a resin; or it may be applied by means of a first coating of a fabric formed of a copolymer of vinyl chloride and acrylonitrile, followed by an impregnation wlth an epoxy resin.
, By a further variant, the foamed in situ plastic is molded as a -skin around at least a part of the framework, to provide a substantially hollow core.
By another aspect of this invention, a minimum weight high strength Ircraft structure is provided comprising: a framework of tubular members;
cablo~ or rods for aileron control, for sroiler aileron control, for flap control, for horlzontal stabilizer control, for vertical stabilizer control, for retractor ~t~
control, for ~teering control and for landing gear assembly control withln selected on-s of sJid tubular members; foamed in situ plastic polded around at least a part of said framework to provide a structure of the requlred shape; and a smooth ~kln over the shaped, foamed in situ plastic.
By variants thereof, the tubes may be for~ed of aluminum or an alumlnum alloy, of magnesium or a magnesium alloy, of steel, or of graphite or ~, boron fibers.
By stlll other variants, the plastlc may be polyurethane, styrofoam $;
or foamable hydrophilic polyisocyanate.
~, By still other variants, the skin may be epoxy resin impregnated ~`1 iE3~.
~ - 3a -, ! ~ , ~,:,; ' ' ' '' ''` , J
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.''~,,~' . , ' ' '" ,, ~Q5~,~87 .
- glass fibers, or epoxy resin impr~nated vinyl ~l~loride/~crylonitrile fibers or Kevlar.
The foamed plastic, whether it be prefoamed pl~stic or foamed in ltu plastic c~n be any of the conventional such foams. Exam~les include poly-r~;; urethane and styrofoam. Another particularly preferred foamed plastic is the '`-', foamable hydrophilic polyisocyanate known by the Trade Mark of Hypol (by W.R.
". :
Crace ~ Co.).
The skin covering the foamèd plastic or foamed in situ plastic may 1,.:, ~
'~: be sny suitable such covering. One type is resin impregnated g]nss fibers.
Another ls Dynel fabric to which epoxy resin has been applied.
In the accompanying drawings, Figure l is a plan view of the tubular framework of one fuselage of an aircraft;
' Figure 2 is a plan view of the finished aircraft derived from the ',h fuselage of Figure l;
,'~r, .. :
,~ Flgure 3 is a front elevational view of the tubular framework of the fuselage of the aircraft of Figure l;
~;' Figure 4 18 a front elevational view of the finished aircraft derived from the fuselage of Figure 3, similar to Figure 2;
Flgure 5 ls a section along line V-V of Figure l; and ;, Figure 6 is a section along line VI-VI of Figure 2.
... .
~' As seen in Figures 1 and 3, the general configur;lLion is similar .~, ~ .
'~ to a tricycle/go-cart hybrid with a tail and with an engine .. ~ , . . .
!r ' ;' ~ ' ., .. . .
~ .
~t~ .
~ , _ 4 _ ;`.' `' ' ' ''' . .
~r_, ' , , ' ' , ., , - . ,,,' ,',,,, ~' ' ' '. , - . - :,' , '~ ~ 1()59487 mounted on the front thereof. Thus~ the framework of the aircraft 10 of one embodiment of this invention includes a fuselage framework 20, front P' wing framework 120 and rear wing framework 220. To facilitate home-built construction, the framework preferably makes use of elbows, tees and epoxy glue or even brazing techniques in order to minimize welding.
The material for the framework may be aluminum, boron, steel o-r magnesium;
~: or graphite fibers in an epoxy matrix. The fuselage framework 20 includes a main framework composed of longitudinally extending, rearward-ly converging left and right spars 21, transversely extending, parallel, 10 - upper and lower forward ribs 22, a rear rib 23 and vertically extending connecting beams 24, all interconnected by elbow connectors 25 and tee connectors 30.
! Superposed on the framework 26 is a cockpit framework 31 also of generally rectangular parallelepiped configuration. Cockpit frame-work 31 also includes a pair of longirudinally extending parallel left and right ribs 32, transversely extending parallel upper and lower ribs l ;
~- 33 and vertically extending beams 34, all interconnected by elbow connec-. tors 25 and tee connectors 30.
One configuration of the wing is shown in Figure 6, to be des-crlbet hereinafter. Furthermore, the wing may be a layered foam/epoxy resin sandwich. During the manufacture thereof, rear flap control tube ~ 122, and transversely spaced-apart aileron control tubes 121 are provided.
d~`
~i~ Two pairs of port flap control hinges and two pairs of starboard flap control hinges 124, and two pairs of port and starboard spoiler aileron control hinges 125 are also provided. A landing gear support beam 128 ~ is provided and depending therefrom and from main spar 126 are a port and '~. a starboard landing gear assembly 129. Landing gear assembly includes a shock absorber mechanism 130, and a wheel 132 freely rotatable in axle .
; 133 extending fror.~ the lower end of shock absorber mechanism 130. The wheels are provided with aerodynamic boots 134 which reduce air resis-tance in the retracted position.
The rear wing structure 220 in Figures 1 and 6 is similar to ~?
't,`~:
';;
~ ~ - 5 -:: :
~ .
~;
lQ59487 ?
, , z the main win~ and includes a rear, vertical stabilizer rotatable control ~"", ~;~! tube 222 and a frame tube 224 which adds to the center section strength, as well as a pair of port and starboard hinges 223.
- Pro~ecting upwardly at the rear of the fuselage 20 to support , the rear wing is a rudder framework 250 including a pair of spaced-apart vertical spars 251 and a pair of spaced-apart horizontal t. ~.:
interconnected to each other and to the fuselage at longitudinal spar 234.
Projecting downwardly at the nose of the fuselage 20 is a steerable and retractable nosewheel assembly 275 including a shock absorber assembly 276, a wheel yoke frame 277 and a wheel 278 freely rotatably mounted on an axle 279 between the forks 280 of the wheel yoke 277. , ~' It will be observed that nose wheel 275 assembly is secured ;~i to a cross-beam 28 within which are disposed the retractor control s, cables and/or rods and the steering control cables and/or rods (not :c shown). These cables and/or rods run in the fuselage framework 21 to controls (not shown) in the cockpit 31.
Control cables and/or rods for the landing gear assemblies 127 ~`~ 20 ure dlsposed within transverse tubular rib 128 and terminate in controls in the cockpit 31.
The flap control tube 122 is rotatable to control the flaps.
Similarly, spoiler aileron control tube 123 is also rotatable to control the spoiler aileron. These tubes are provided with operation means which terminate in controls in the cockpit 31.
ij; The horizontal stabilizer is operated by a push rod inside a longitudinally extending vertical stabilizer control spar 2~.
The vertical stabilizer control for the rudder is provided by cables running inside the rearwardly extending ribs 21. The controls ;
all terminate in the cockpit 31.
Fi~ure 6 shows the construction of a typical wing, spoiler and associated tubular supports and hinge. The hinge 125 includes fixed '' ~ ~Q59487 r .
~" "
,.
tube 121 (whi~h may be tube 221), tube 123 and tube 122. Spoiler 119 is shown deployed. Rotation is achieved by either sleeve, or bearing means, and is achieved for the fla~s about tube 122 and for the spoiler r ~" 119 about tube 123.
Once the framework 10 has been assembled, thc~ molding procedure takes place. The framework is placed in a suitably shaped mold. Because the fuselage is so large, sectional molds may be used. It is necessary also to provide an inner mandrel, e.g. an inflatable upper mandrel, to provide a hollow fuselage to minimize the amount of foamed in situ ~ plastic required.
p;. As mentioned before, the foamed-on plastic could be sprayed over the framework rather than using an external mold.
Similarly, the wings and rudder may be formed the same way, although the need for a hollow internal mandrel is not so necessary.
In addition, the wings and rudder can be formed as multilayered sand-wiches of foamed plastic epoxy resin. However, even in such small parts, the exact shape i8 not required for the mold. Wing roots, tops, fillets and ~oints can be exquisitely faired to the desired shape at will with .~, . .
sandpaper.
Moreover, for larger areas, part of the plastic may be provided by preformed sheets which are secured to the framework, and to which the foamed in situ plastic adheres .f~ _ ~p, Once the plastic has been shaped to the exact shape, it is covered with a protective skin.
As mentioned before, the foamed in situ plastic can be of any of the conventional such foams. Exmaples include polyurethane and styro-foam. Another particularly preferred polyisocyanate is known by the Trade Mark of Hypol (of W.R. Grace ~ Co.).
An example of a wing section is shown in Figure 6. The frame-work includes tubes 121, 122, 123 ~oined by plate 130. The foamed in .
~` situ plastic 131 surrounds the framework and is shaped to the proper .
.
:~
. ,, ' ~. ' ' ' , .
lOS9487 aerodynamic form. The skln 132 covers the foam 131.
This provides a fnished aircraft as shown in Figures 2 ant 4 including a fuselage 420, front wing 421, flaps 422, rear wing 423, stablll~er 424, tnll 425, and rudder 426. A preformed acrylic plastic canopy 427 covers the cockplt 428. Conventional means are provided for retracting the wheels into the open area o~ the flaps.
Claims (22)
1. A process for the formation of a minimum weight, high strength aircraft, the process comprising: forming a framework of the desired shape from light-weight structural tubular members; providing cables or rods for aileron control, for spoiler aileron control, for flap control, for horizontal stabilizer control, for vertical stabilizer controls for retractor control, for steering control and for landing gear assembly control within selected ones of said tubular members; providing at least a portion of the exterior surface of the aircraft of approximately or exactly the desired shape by foaming a plastic in situ about a combination of such framework and a mold; separating the molded air-craft from the mold; and applying a final coating to the molded aircraft.
2. The process of claim 1 wherein the mold is an external mold, and wherein the steps comprise: placing the framework in a mold of approximately or exactly the desired shape; providing a foamed in situ plastic around and adhered to at least part of the framework, and contacting the interior surface of the molt so as to conform generally to the configuration of the mold; and removing the molded structure from the mold.
3. The process of claim 1 wherein the mold is a hollow mandrel.
4. The process of claim 1 wherein the mold is of approximately the final shape required for the molded structure, and including the additional step of manually configuring the molded product to the final shape required for the molded structure.
5. The process of claim 1 wherein the entire foamed structure is provided by the foamed in situ plastic.
6. The process of claim 1 wherein selected areas of the framework are filled with a preformed plastic foam.
7. The process of claim 1 including at least one of additional foam and layers of glass fibers and resin are deposited at stress points of the fuselage.
8. The process of claim 1 wherein the wing is formed by multi-layers of foamed plastic and epoxy resin. 9
9. The process of claim 1 wherein the final coating is applied by means of a first coating of glass fibers followed by an impregnation of the glass fibers with a resin.
10. The process of claim 1 wherein the final coating is applied by means of a first coating of a fabric formed of a copolymer of vinyl chloride and acrylonitrile, followed by an impregnation with an epoxy resin.
11. The process of claim 1 in which the foamed in situ plastic 18 molded as a skin around at least a part of the framework, to provide a substantially hollow core.
12. A minimum weight, high strength aircraft structure comprising: a framework of tubular members; cables or rods for aileron control, for spoiler aileron control, for flap control, for horizontal stabilizer control, for vertical stabilizer control. for retractor control, for steering control and for landing gear assembly control within selected ones of said tubular members; foamed in situ plastic molded around at least a part of said framework to provide a structure of the required shape; and a smooth skin over the shaped, foamed in situ plastic.
13. The aircraft structure of claim 12 in which the tubes are formed of aluminum, or an aluminum alloy.
14. The aircraft structure of claim 12 in which the tubes are formed of magnesium or magnesium alloy.
15. The aircraft structure of claim 12 wherein the tubes are formed of steel.
16. The aircraft structure of claim 12 wherein the tubes are formed of graphite of boron fibers.
17. The aircraft structure of claim 12 in which the plastic is poly-urethane.
18. The aircraft structure of claim 12 in which the plastic is styrofoam.
19. The aircraft structure of claim 12 in which the plastic is foamable hydrophilic polyisocyanate.
20. The aircraft structure of claim 12 in which the skin is epoxy resin impregnated glass fibers.
21. The aircraft structure of claim 12 in which the skin is epoxy resin impregnated vinyl chloride/acrylonitrile fibers.
22. The aircraft structure of claim 12 in which the skin is Kevlar.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA252,815A CA1059487A (en) | 1976-05-18 | 1976-05-18 | Minimum weight and high strength framed structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA252,815A CA1059487A (en) | 1976-05-18 | 1976-05-18 | Minimum weight and high strength framed structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1059487A true CA1059487A (en) | 1979-07-31 |
Family
ID=4105994
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA252,815A Expired CA1059487A (en) | 1976-05-18 | 1976-05-18 | Minimum weight and high strength framed structure |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1059487A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0846540A2 (en) * | 1996-12-06 | 1998-06-10 | British Aerospace Public Limited Company | Manufacture of composite laminates |
| WO2011131382A1 (en) * | 2010-04-19 | 2011-10-27 | Gatewing Nv | A wing for an unmanned aircraft |
| DE102015013349B4 (en) | 2015-10-15 | 2023-05-17 | Mbda Deutschland Gmbh | Method of operating a weapon system |
-
1976
- 1976-05-18 CA CA252,815A patent/CA1059487A/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0846540A2 (en) * | 1996-12-06 | 1998-06-10 | British Aerospace Public Limited Company | Manufacture of composite laminates |
| EP0846540A3 (en) * | 1996-12-06 | 1999-05-12 | British Aerospace Public Limited Company | Manufacture of composite laminates |
| US6048477A (en) * | 1996-12-06 | 2000-04-11 | British Aerospace Public Limited Company | Manufacture of composite laminates |
| WO2011131382A1 (en) * | 2010-04-19 | 2011-10-27 | Gatewing Nv | A wing for an unmanned aircraft |
| EP2377757B1 (en) * | 2010-04-19 | 2013-05-29 | Gatewing NV | Unmanned aircraft |
| US8827206B2 (en) | 2010-04-19 | 2014-09-09 | Gatewing Nv | Wing for an unmanned aircraft |
| AU2011244639B2 (en) * | 2010-04-19 | 2014-10-30 | Gatewing Nv | A wing for an unmanned aircraft |
| DE102015013349B4 (en) | 2015-10-15 | 2023-05-17 | Mbda Deutschland Gmbh | Method of operating a weapon system |
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