CA2039680A1 - Winged ram pressure watercraft - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A winged, ram pressure and ground effect operated watercraft improved by laterally effective, downward pivoting blades for the plenum under the wings, causing air pressure to leak from underneath the wing when the craft has an elevation of more that about one third its wingspan; and a sealing skirt on the trailing edge bounds the plenum for elevations of the craft in a near surface elevation only, so that in cooperation with the blades the craft is prevented from attaining a free flight state and mode of operation.

Description

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:~OM ~EEilLEf~ Pfl~)lTT (111~ 04 . ~ g6 I~lu. 1 ~FIEIF ~15 BI~ J 105 WINGED RAM PRF,:~SUF~ WATERCRAF

~KC}~OI~Nl~ F THE I~VE~TIOI~

Th~ present inven~ioll relates to a ram-pressure wing, g~,ound effec~
watercraf~ which floats on water at zero ~peed or ~rery slowl speeds but ~hîch lifts out of the water with increasing speed and glidel above the surface of th~ wat~r on a dynarnically gsner~ted and mai~tained ai~
10 cushion~ as a ~round effect de~ice al:ld will ~emain, as ~ as lift is conce~ed~ within thi~ region of g~ound e~fect.

With increasing t;he li~t and concurrent reduction of re~ist~nce and dra as one win~ approache~ ~ound, it is Icnown to be tLeuretic~lly 5 ~easible to obtain ~ er2 ft in so-called win~-in-~gxound effect c~n~iguration or "wi~" for shor~, and to use ram pressure under the wi~g as a lift produci~ ~ut ~round effect de~ic~ a~ ~utlined above. It is a ~equileme~t ~o~ such ~n effec~ to tak~ place that the ~1ide number is in fa~ improved.
This mea~s a hi~hly e~fective ~rans~rmation o~ thP dyna~ic r~ pressu~
20 into a s~atic e~ces~ pre~sure is Iequi~d. For this to o~tain, ohe ~eeds ~n opeI~in~ at the fro~t a~d hi~hly eff~ctiYe la~eral and ~ar ~nd se~li~ of the wing ~o pex~nit developmen~ of ram and ~ynan~ic pressllre in a plenum undern~dth th~ cr~, (i.e. be~we~ h~ ~ra~'~ body taken ~s al wholc; and the wate~ su~ace). A ~lraft ~onceived irl such a manner shoul~ pe~ , of 25 course~ a~ ~dvanta~ s ~vnfiguratic~n ~.s a ship o~ boat,'.par~i~ularly owing tO the fa~t ~h~t ~h~ wat~r sur~ac~ is 3~eneral1y a planc s~fa~e. ~ince the cra~t i~ ~uppo~ed tc~ be airbo~ne, it mu~E b~ ~ery li~ht, ~hil~ on th~
Ij F R O M B E E H L E R P l~ u l T T ~ 3 4 ~ 0 I ~ ' g l ~ 7 ,~I O . I P ~ q E ~

~ ~3 ~ 9 ~ 8 0 ' other hand, it mu8~ resist high loads through water impact~ ~articularly ~lu~in~ the ~ake~ d landin~ phase~. ~

The ~ater resistance to be overcome du~in~ ~ake-o~f i~ ~bout 2 to 5 3 times as la~ge as th~ air ~sistan~e to be overc~me when ~he Icraft moves in an airbomo mode clo~e to the ~rouncl This is ~ue to the faft that water is 800 tirn~s as dense as air~ Con~equently, the propulsion power requireme~t is ~ominated by the requirements for tal~e-off. The prop~lsion needed on take-of~, on the other hand hand, is primarily 10 determined by the weight of ~he c~aft at the time o~ take-off, There-fore wi~h the ~ed~c~ion in weight owin~ to filel consumption or lo~ additional loads the craft will in fact e~cpe~ience dyllamic f~ee flight, ~i.ei well above the ~round effect), but still the grvund effect i~ effective a~ jlon~ as the craft is ~ot higher ~o that at leasl; o~e third of the wing spaI~ and for the I S entire win~ depth experiences ~round ~ffect. (: onsequently, lhls kind boat,particularly if actu~ controllable about 3 axes, could ju~ti~lably be termed an aircraft; ~ specti~e of the label attached to such ~ craft, free-flight oper~ting ~nodes w~uld re~uire, for ex~mple, ~rplane I el; i~ would require customa~y ~ircra~t p~opulsion ~ s aI~d, not least, ~hould it be 20 tçrmed an "aircra~", îts opçration woul~ xequire ai~ pilot clerti~lcation.
All thi~ is, of course, a decisive cost ~ac~or and not just anybody will be allowed to op~at~ ~uc~ a cr~
.
Another kind of vessel is ~nown which comes under ~he name of 2 5 tandem air~foil b~at, wh~rcin the~ is a ~round-depeIldent di~t~bu~ion of li~ o~ account of ~ ta~deln win~ss being a~anged on~ behi~d ~he other~
This a~angement, ~ effe~t~ is supposed to ~ake su~ that ¦~he distance , : ' `

R O M ~ E E H L E, :I V I T T ( 11 Cl 1~ ) 0 4 . ~ I a g~ E 4 ~
¦1 E5IS J 105 . l f~m ground remams slight. However, tbis kind o~ Yesse1 andl cra~t has ~
very limited maneuverability because ~or example, t~ey cannol bank while flying in a curve ~o~ use elevatiol1al changes under utilizatiol, of kinetic ener~y, for example, to jump over obstacl~s. Owin~ to the In~ssing 5 elevational corltrolJ it is IlOt pos~iible to guid~ the craft back lowards a ground near-flight l,evel, in case, for e~ample, the elevation lo~ the craft happens to increase as a resul~ of, for exa~ple, air flow developments or oper~tor erro$s. This is so ~ecause once g~und effect is no longer ef~ective, stability of movement is impaired and the craft is nv longer 10 ~dequately maneuve~able.. ~ ;

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: ~ It is a feature of the prese~ invention to improve r~m pressure wing-grolmd effec~ wa~e~ crafts towards avoidin~ free-fli~h~ conditions and its comn~ensurate disadvantages, by employing a rar~-wing boat co~ guration arld co~struction wherein ~he resistanc~ on ~Ibtaining ~n 0 ele~atioll in exces~ ~f one third 4f the win~ span i~ ~ar~er th~n ~he water resist~n~ to be ove~o~e durin~ take~o~, so that free ~light ls inherently avoi~ed without ~he aid of a~ificia1 means such as elevation~dependent a~tvm~ co~trol o~poYV~r reduction It i8 therefore an object of the p~esellt ~vention ~o pr~vide a craft ~5 and wing ~on~1~ur~ n, as well as ~ sealin~ ~truetu~e fo~1the plenum ILndemeath $h~ ~ra~t, which a~oids ae~vdynamic free-llight siTply th~ough : 3 .

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f R O lt~ E E E H L E R P R ~ T ~ M O ~i ~ 0 4 . ~ 1 0 a ~ , I P ~ E S / 1 ~;

increasin~ the resista~ce over the resistance found on také-o~ when the cra~ exceeds cer~ain eleva~io~lal values.
The ~biect and feature are obtained in a ver~ small ~p~n width and great wing depth w~icll are reflected in a sid~ satio ~nd whichlwill in fact S cause an increase in i~duced re~istance wheneYer the cra~t's al~itude incr~ases. Th~ particular features involved conccrll the sealing of the ram pressllr~ developin~ plenum; the t~ailin~ ed~e of the win~g is ~qunded by a yieldin~ p-like s~cirt configuratioll, and the sides of the ple I um, e 8- at the wing tips, is ~ounded by hin~edly yielding blad~s that may pivot o~
10 hori~ontal transYerse axes. C)~ the other hand, the same ~eatures actually red~ee resistance ontake-o~f.
Th~ t is thu~ controllabl& throu~h control of the lat~ral and rear sealin~ 4f the pressure plen~m beneath the cra~t, particul~rl~ the win~s~
such th~n on th~ o~e hand, hi~h li~t and low r~sistance obtain j~uring takQ-15 off but the lif~ is reduced a~d resistance as ~he cra~t movels above ~hewater su~ace are such ~hat in fact the cra* will never ~et hi~helr than about on~ third of ~e spall above ground in a self-cc)lTecting manne~ lf the craf~
were to rise fur~er, the ple~um would just lose ef~ectiYeneSS, t~e rear ski~t and lateral bla~es no longer containin~ tlne pressuri~ed air3 I d the c~af~
20 wouldo~ceagain descend.
On order the l~a~e rear water speed as ~mall as possibte, ~e wing~
should be as light as possibl~, th~ wing~, of course~ OCCUpyi~ the lar~est volume in t~e const~ctioIl, all th~ w~ile the co~truction ~aYi~ to be ~lrm ~d resista~ a~inst lo~d from w~ter impacts. Tberefq~, the rear 2 5 stmcture, parti~ula~y when th~ ~ra~t ~s a whole is sma~l? is p¦efe~ably not of t~e u~ual r~b spar con~1guration no~ covered ~vith as stiff ~ nlaterial as skin, but is, r~her, re~dered ~lastic throu~gh a flexible skin Icove~ing. In : ' .

R 011 e E E H L E R P fJ U I T T ~ ~1 b ~J ) 0 4, ~ ~ " ~3 1 2~g ~ 3 ~ P ~J r7 E ~

order to obt~in hi~h li~t, one clevia~es from p~oposals in ~;erman Patent 25 .: 47 945 which provides a on~-~ided sail; and in the present c Ise a doubLe coverage is providcd in o~der to obtain optimum p~ofile confi~uration.
O~e-sided skin coverage, of cours~, can~es with it the risk thaf water can 5 enter the win~ ~ecause the WiIlg, prior and dur~n~ take-off naturally rests ;". I
on the water, and the ensuin~ entrance of water m~y inereas~ weight and could, if not Avoided, cause an uncontrolled and par~;icularly an unsymmet~cal shift in the center of ~ravity. On the other hand7, in the case o~ a double coveringJ only dama~e can ~ive rise to ingress of ~ate~. In ~he 10 static displacemen~ state, the rear or ~railin~ ed~se of th~ wing has ~o be der the watel's su~ace prior to talce-o~ and over the entire 1~n~th o~ ~he wing, so th~ on lift of~ t~ailin~ edge sealing of the plenuL~ is in fact gua~anteed.
. i DE~I~I~OF ~ R~WI~GS

While the specifieation concludes with claims llparti~ularly poi~tin~ out and distinctly c1aiming the subject matter whi~ isl ~ga~ded as the inventio~, it i~ believed that the invention~ the objçcts and features of 20 the invention and f~r~sr objects, ~eatures and ad~Janta~es the'feo~ will b~
better understood f~om th~ followin dese~ipti4n taken in con~ection with the accompanyin~ ~awin,~s in which: li .. . .

Fi~. 1 is ~ p~rspec~ive ove~view of a cra~t in ~ çc Irdance with 2 5 the pr~ferred embodin~ent of the pre~ent inver~tion;

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: 5 :~' FROM EEEHLEI~ P~l~)ITT ~11tllJ>~q.~ tl~. I Pf/ci~ 7/1~
s 1 1~5 Figur~ ~ îllustratcs on an ~nlar ed sc~le and in ~ somewhat schematic b~sis detail~ of ~he const~uction of a ~in~; ~
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Fi~ure 3 is a cross section through the wirlg illustrating, 5parti~ularly, a rear or trailin~ edge and a skirt in a conditibn of static displacement;

~ gure 4 is a vi~w si~Pilar to Figure 3 but showing take-off and I~ndin$ pha~es with displaced trailing ed~e ski~t;
., 10 Figure S illustlates ~he fli~ht col~dition close to ~roul nd;

Pi~u~e 6 illus~rates the ~aft sho~n in Fi,~. 1 withl a particular confi~ tion of l~te~al sealiIlg;
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Fi~ure 7 illustrates the displacemen~ condition sho~ Fi~g. 6 but in a ~ront view;
!l Fi~ure 8 illustrates the flight co~dition when the ~rai~t is near 2 0 ~e water surface~ ¦

Fi~ur~ 9 ~llustrates the ~ont view of the operalio~al phase depicted in Fi~ure 8; and 2 5Fi~ajure :iO show~ a ~ont ~iew of the craf~ ~ a whlo~ showill~
p~rticularly t}~e seali~ ef~ect o~ ~nking flight w~en a cu~ve is negotiated.
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R O 11 B E E H L E R P R V ~ T T ~ M ~ IJ ~ ~i 4 . 0 1 . ~ 3 1 ~18 ~ . I P h ~i E s~ 5 r~ ~ 315 1 1ûS
.` . . 11 Prvceedin~ now to ~ detailed desc~iption of th~ drawil gs, Fig. 1 illust~ates a cra~t wi :h a body 20, a shrouded propelle~ unit 21l on top of `the fusela~ge 20 as a propulsion urlit, and elevatio~al con~rol 2~ in the rear or aft poltion of th~ craft. Of cAtical i~portance is a wing 1 ~Ivith a nose 11 bein~ of a profile-definin~ solid structure, for example, wood synthetic or even rnetal slcin. Ill addition, Fig. 1 shows flot~tion bodies g and 8aS and outer, upstanding win~lets 10 and 10a, rearwardly pivotable and defle~table blades 12 and 12~ are pi~otal~y mounted to the flotation bodies 8 a~d 8a respectively. Suppo~ structures 3 and 6; and la ~kirt 5 o~
flexible con~lguratio~ will be dcse~bed more fully below.

Fi~ure ~ shows in ~re~ter detail the structure for the ~ ing nose 1, and there is ~ skin cover 4 in the central and rear pare of ~hle wi~.The trailing ed~e is ~ormed at a ten~ioned cable 2 in ~he case of a ~exible skin cov~r 4, Y hile i~ case the trailillg win~ ed~e is defined by a si~id or sti~
~e~r edge bar, the skin cover of the win~ is ~Iso stif~. For supporting the tr~iIing e~e durin~ take-o~ and landing, particularly wherl jthe trailing ed~e is sub~e~d in water and ther~fore subiected to impac~s by the ~ate~, sti~ support bar~ 3 are provided and extend fro~ the Ibody of ~he 2 0 craft at an angle towards the rear. T~ese bal~s ~r sp~rs havel to a~oid bulgin~ of the trailing ed~e which is particul~rly possible i~ the traili~g - edge is con~l~ured a~ a cable. Thi~ buIgin~ ma~ be the resulI of head or r~m pressure in the plenum undemeath the Willg ~or~ ura$~on; but the rear ed~,e has to re~ain straight iIl o~der to maintain the prelssure in the ~5 plenum~ i.e, in o~er to prevent cxcessiv~ le~ e f~om underneath tho c~ft's body.
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, 'R4M BEEHLEI~ P~IUITT ~.llON ~4, ~ g~ Ji. I F~ 5'i~
~ 105 . . !
A flexible skirt 5 is provided along ~he trailin~ edge 2 w~ch skirt, Ln t~e cas~ of st~ic condition, simply dips into the water surface as shown in Figure ~. This sk~ is o:f a one-sided con~lgur~tion so that ~ater cannot enter into cavities, as ~rould otherwise be possible. The flexiible skirt is 5 supported and held by me~ns of resilient spars ~, thus avoidilhg vibration during flight, On the o~er hand, th~ skir~ 5, owing to thl par~icular stiffness and resilience of th~ spars ~, can yield to mo~ing wal er; ~nd this is not only pe~mitted but desirable. The sprin~ sti~fness of ~ spars 6 is d~termilled such th~t during fast moveme~t in and on water, ~~r ~xampl~, 10 durin~ take-of~ the skirt will sli~ on th~ water surface 7 wl ile ~ippin~
o~ly s1i~htly in~o the water at take off and this sig~ can~1y r~duces dra~g and resistance durin~, talce-of~. Th}s is ne~essary in order to keep ~e power requirement in the take-off phase as low as possib1e, ~nd to ~v~id the above-me~tioned ~ree~fli~he; the craft is ~hus positively prevented 15 ~om becom~n~ and being te}med ~ ai~af~

Pi~u~ 3 sho~s the ~ki~t 5 ~s well a~ ~he ~lient and sprin~g-like support bar ~ the static displa~em~nt state while Fi~. 4, ln the othcr h~d, shvw~ on talce-o~ ~ut al~o during landin~, how the skirt ~i has shi~ed O into an orientatioll p~r~llel to the w~ter surf~ce 7.
Pi u~e 5 zlow illustrates a fli~ht ~ondi~io~ close to the ~ater sur~ca 7 Yvhere ~e resilient sl~irt ~ seals the plenum $~wards the re~r.l ~n all ~ese operatin~ conditi~ns, loads on the }oad-bearin~ ture i9 alvoid~d, a~d particul~rl~ th~ case of contact with water and waves, the fi~ure shows 2 5 ~e r~ady yieldability of cn~ic~1 components which iII additio . to b~in~ a weight-reducin~ fac~or, e~hances ~a~ty F R t) ~1 E E E H L ~ R P FI U I T T ~ 1~ 0 ~ l 4 . 1~ 1 2 ,~10 . I p Fl ~ F 1 IS f 105 11l order to ~bt~i~ a low propulsion power input during take-of~ an~
close to ~round flight~ ~i.e. in order to asvOid f~ee-fli~ht in la dyn~mic sense,) ~?Se pleIlum InsUSt also b~ laterally seal~d, but such that als the craft's elevation inc~ease~ i~ a~titude above wate~, the resista~ce Idrastically 5 increas~s so that the era~t will return to near-~round conditi Ins. This is obtained by providin~g for a slowly inc~easin~ indllced resist~nce with a chose~ extremely low side ratio of span-wing-to-wi~ are~.l This ~tio exeeeds the air resist~ce of the elltire craft and thus ~imply ~reYents ~he cra~'s b~in~ able to reach an altitu~e a~o~ abou~ on~ third of the ~rin~-1 0 span.

The ~levelopment of a dynamic ~ir cushion req~,lires, accordingly~
sealin~ of t'~e plenuln not only in the rear but also la~erally ~sl lon~ ~s the ~raft moves ,^lose to the water's surface up to ~ particular eleYal ional ~evel.15 This lateral seali~ olves, pa~icul~rly, th~ wing-~ips which ar~, fo~
reasons of safety, con~l~ured as sllppo~ g flotation boclies g a~d 8a. In order ta obtain a ~tatic floating condition e~ireIl when the cFaf~ is ~ully loaded, a cer~in buoyancy displacemell~ is inevitable, which means tha~ the - fron~ of the cra~'s bod~ for example, as well as the f~otation ~odi~s 8 and 2 0 8a, ~as to be immersed to somQ exten~ in water. This i~;nmersioln shQuld be kept as low a5 possible in orde~ to minimi~e the gap betwee~ tr~iling edge of the wing and the w~ter sur~ac~ when thc cra~t moves close to the ~round. (~ he othcr hand h~wever, the ~e~ista~ee on talce-olf~ has to ~e kept as small as possible and, o~ coursç, if ~ ra~ a~ a wbl le dips too 2 ~ deeply in~o the water, ~t resistallce i~ ineYit;abl~ hi~h.
-~ Ther~ore, ~he penetra~ion of elements provided alon~g the ~railin~
ed~e is t~ b~ kept as small as possi~le, pa~ ularly dllri~ ake-of~ and .. I
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ROM 13EEHLER PhlJlTT ~Ml3N)el4~0l .912~,~ ;y3~ ~3~ ~ ' Pfll3E 1!/15 ,~ i j B1S 1 105 landillg. In o~der to ~neet this requiremen~, the outer flotation blodies 8 and 8a a~ provided with the hinged vertical blades 12 and 12a configured as follows. During floating, the blades are late~lly deflected and ~est on the water, i.e. tb~y do not dip into the wat0r and therefore do not Increase the - S water ~esistance on slow speedx, but as the craft li~ somewhai, the blades 1~ and 12a, p~ticularly in the sliding mode, will piv~t do~n and thus laterally seal the ~e~r part of the ple~um underneath the planels body and fuselage. The blades wiil pi~ot more ~r less into a vertical pOSitlO:Il as the cr~ft inc~e~ses in altitude~ ~ut once th& blade~ h~ng ~traight down, further increase in th~ c~f~'s al-~itude ope~s a ~ap betweel~ the blades alld the water surface. On the othe~ hand, ~e yieldin~ I han~in~ suspensio~ of the blades ass~res th~t as water hits the blade ~ro~ one side~ ~or examp~e owin~ ~o w~YeS, no acceleration loads a~d ~om~ts occur"
., l l S The i~ventive arrangement provi~es that in cas~ o~ a ti~ht ban~cing a~d cuNi~J the air-cushioll, p~r~icularly on Ihe side o~ the li~ted wing, is ~ot imp~ired, I~ order to p~rmlt a bankin~ position, tra~svlr~e ~dder~
a~ provided at the wing as a l~md o~ ~Ipr~gh~ wi~ t. The l¢f~ctiYeness ~ear ~rou~d is limited ~uch ~at, as a wing por~ion comes vl ~y close to the ~ound or ~ç wat~r s~rface, that wing portio~ will cause a compression of ~ aix cushion u~derneath, ~nd that comprel sion would of course a~ ~gai~st ban}ci~, but in th~ ~,se of ~ralnsverse rudde~s whieh ~e too la~7 would have ~o be compensated t~r~u~h low-we;~l;, arti~lciat resistance, and so ~orth, MoreoYer, aæ the vther win~-end par~ 1if~s, cushiion support will b~ los~ so that the ~tal lif~ is reduced, and tha~ of ~ou~se csuld lead to ~o~ t with water, which ~ain, couid I vrmally b~
- a~oided thro~h elevational cont~ol. Al1 this again provldes c~?nditio~s for ..

R011 ~3EEHLER P~IIJITT ~11CIMJ04.~ 13 ,il~, I PFlli 1~/15 2 ~ fi5 ~ ~ !
operating the cra~t which would caus~ it to bs termed ~ a~rcra~, and the - operator ~ould as a result have to meet pilo~ re4uirements, the cra~t could o lo~er be;n~ termed a boat. The structure that will be des~ribed next avoids these problems.

Fi~ure 6 illustratcs ~he cffect of lateral sealing in accoldance with the invention. ~t includ~s, as stated~ the flotation body 8, a s lep 9~ outer upstanding winglct 10, trans~erse ~dder 11~ as weJl as blas~le 12 which can be rearwardly lifted and is itsel~ prwided with a securel~ co~mected ~uoyaIlcy body 13, the blade is ~reely pivotable through a F~in 14 on a horizontal tr~ns~e~sely e7~tending axis Thes~ parts are in ~act $1ecured in a ~i~id fashion to the ~vin~ 15. The illustr~tion of Fig ~ i~ that ff t~e staiic displacement wbe~e th~ flatation body 8 is submerg~d in waterjup u~til the rear or tr~ilin~ ed~e lifts o~. Fi~,ure 7 il1ustrates this dl'splacemen~
condit~on in f~ont view as stated abov~.
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~ ow as ~r as operation is conce~ned, Fi~u~e ~ illustr~te~ the near - ground nloving where ~h~ blade 12 is pivoted down untill reachin~ a certain stap3 owin to ~e gravity, so ~hat the pte~um is and remaitls sealed 2 O agaiIlst the outside. In cas~ of conta~ with waterl for example thro~h a wa~e, t~e fl~atin~ body 13 sisnpl~ provides ~ yieldin$ Qf ~he bfade, it so to ~peal$ ~oes with the waves, thus a~oidtn~ undue loads on ~he s~ructure.
Fi~ure ~ illus~rate~ ~ same situa~ion but in front ~iew.
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P;~. 10 now illuitr~tes th~ oYerall s~alin~ e~fect of t~e i~v~ntive structure thro~h ~ one sido blade Gonff~u~ation when th 1' cra~t ba~s and flies in ~ cur~e. A particul~r eoll~agwra~ion h~vin~ ~re~Lt a~Yanta~e '' 11 , .

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'' , ' -~OM E~EEHLE~ P1JITT ~Mt~ 8, 14 NO. I PFl1~E 13/I:~

2 ~ IS I 105 ~esults frum the comblnation of the two killds of sealing.as shol~vn, namely the y~elding ~ the trailin~ edge skirt 5 ~nd the pivota~le bla!des 12 and 12a. The cont~ol of ~h~ skirt 5 i~ dependençe upon ~he blade 12~12a can be Inade p~ssible through mechallical lilllcage or through active control element becausc the blade which non:n~lly hangs down ~reely lan be used ~s distance or ~levational transducer. Th~ control of the skir~ or the blades can be carried out manua~ly throu~h the boat operato~.
., The pa~icula~ ram-win~ boat illus~rated is indeed a bo1t which can 10 be operated wi~hout ~equi~i~ any sp~cial ce~i~lcation requjrements.
~ree-flight is avoided owin~ to the reduced propulsion limited Ito the take-off and t~e confi~uration which simp1y prevellts the cIaft j~from being vperated as an aircr~t and everl in a lifted pha~e remains a b lat ow~n~ to the interAction betwee;tl the various parts and t~e water whjch remains 15 throu~houtthe fli~ht phases.

The in~ention is ~ot li~ited to the embodimen~s described above but all changes a~d modific~ion6 thereof, not corlsti~tin~ dep~tures fx~m the s~?irit and scope o~ the invention~ ~re intended to be in~luded.
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Claims (6)

1. Claim 1. Winged, ram pressure and ground effect operated watercraft, the wing having lateral tips and a trailing edge, there being a craft body and propulsion means, further comprising;
   laterally effective, yielding seals for the plenum under the wings, causing air pressure to leak from underneath the wing when the craft has an elevation of more that about one third its wingspan; and sealing skirt means on the trailing edge to bound the plenum for elevations of the craft in a near surface elevation only, so that in cooperation with the laterally effective sealing means the craft is prevented from attaining a free flight state and mode of operation.
2. Claim 2. Watercraft as in claim 1, skirt being yielding and pivotable about axis means along the rear edge of the wing.
3. Claim 3. Watercraft as in claim 2, the skirt having no hollow spaces.
4. Claim 4 Watercraft as in claim 1, the lateral sealing means being pivotable blades at the wing tips.
5. Claim 5. Watercraft as in claim 4, the blades carrying floatation bodies to prevent deep dipping into the water.
6. Claim 6. Watercraft as in claim 4, the blades pivoting on transverse axes.