Luigi PELLARINI Airtruk -- Articles & patents
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[**rexresearch1.com**](http://rexresearch1.com/)
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**Luigi PELLARINI**
**Airtruk Airdynecraft**
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[**http://www.transfield.com.au/THfirst60years/03-transfield-takes-off-transavia/129-m03-page-1**](http://www.transfield.com.au/THfirst60years/03-transfield-takes-off-transavia/129-m03-page-1)
 
 
  
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[**https://en.wikipedia.org/wiki/Transavia\_PL-12\_Airtruk**](https://en.wikipedia.org/wiki/Transavia_PL-12_Airtruk)**Transavia PL-12 Airtruk**
The Transavia
PL-12 Airtruk is a single-engine agricultural aircraft designed
and built by the Transavia Corporation in Australia. The Airtruk
is a shoulder-wing strut braced sesquiplane of all-metal
construction, with the cockpit mounted above a tractor-location
opposed-cylinder air-cooled engine and short pod fuselage with
rear door. The engine cowling, rear fuselage and top decking are
of fibreglass. It has a tricycle undercarriage, the main units
of which are carried on the lower sesquiplane wings. It has twin
tail booms with two unconnected tails. Its first flight was on
22 April 1965, and was certified on 10 February 1966.[2]
A Transavia
PL-12 featured in the 1985 movie Mad Max Beyond Thunderdome.
**Design and
development**
It was
developed from the Bennett Airtruck designed in New Zealand by
Luigi Pellarini. It has a 1 tonne capacity hopper and is able to
ferry two passengers as a topdresser. Other versions can be used
as cargo, ambulance or aerial survey aircraft, and carry one
passenger in the top deck and four in the lower deck.
The Airtruk is
also sometimes known as the Airtruck. Because the name
"Airtruck" was registered by the New Zealand companies Bennett
Aviation Ltd and Waitomo Aircraft Ltd, for their PL-11,
Transavia found another name for their PL-12 ("Airtruk").
July 1978 saw
the first flight of an improved model, the T-300 Skyfarmer,
which was powered by a Textron Lycoming IO-540-engine. This was
followed in 1981 by the T-300A with improved aerodynamics.[2]
Transavia ceased production of the T-300 in 1985.
In 1982
certification was undertaken to enable sales in the North
American market. Assistance was provided by the Aeronautical
Research Laboratories (ARL) of the Defence Science and
Technology Organisation (DSTO) and extensive tests carried out
on the ground and in subsequent flight flutter clearance trials.
ref. DSTO Structures Tech. Memo. 341
In 1985 an
extended version was produced and released as the T-400. The
engine was changed from a 6-cylinder to an 8-cylinder and the
tail booms extended by 750 millimetres (30 in). Other minor
changes were made to the aerodynamics. Flutter clearance tests
were again carried out by ARL and manufacture proceeded.[3]
An isolated
flutter incident was reported in 1986 involving violent
oscillations of the rudder and tail boom on the T-400 during a
delivery flight. Investigations were carried out by ARL and a
split mass balance arm was fitted to each rudder. Prior to this
the aircraft had relied on frictional damping provided by the
lengthy control cables. The modified aircraft was tested both on
the ground, and in flight trials in March 1988 over Port Philip
near Melbourne, Australia. All attempts to induce the
oscillations showed that there was no indication of a mode of
vibration becoming unstable. The maximum speed achieved was 160
knots (180 mph; 300 km/h) in a steep dive. Oscillations were
induced with an air operated tool fitted with an out-of-balance
rotating mass. This device had a rotational speed from 18 Hz
down to zero for each charge of the compressed air cylinder.[4]
At least 120
had been built by 1988.[2] ...
**General
characteristics**
Crew: 1
Capacity: 2 pax / 2,000 lb (910 kg) dry
chemicals or 818 L (216 US gal; 180 imp gal) liquids
Length: 21 ft 0 in (6.4 m)
Wingspan: 39 ft 4 in (11.98 m)
Height: 9 ft 0 in (2.74 m)
Wing area: 256 sq ft (23.8 m2)
Airfoil: NACA 23012
Empty weight: 1,709 lb (775 kg) :: PL-12U
1,830 lb (830 kg)
Max takeoff weight: 4,090 lb (1,855 kg)
(agricultural mission)
Fuel capacity: 181.5 L (47.9 US gal; 39.9 imp
gal) in two upper wing fuel tanks with optional second tank in
each wing for a total of 373 L (99 US gal; 82 imp gal)
Powerplant: 1 A Rolls-Royce/Continental
IO-520-D 6-cyl. air-cooled horizontally opposed piston engine,
300 hp (220 kW)
Propellers: 2-bladed McCauley D2A34C58/90AT-2
constant speed metal propeller, 7 ft 4 in (2.23 m) diameter
**Performance**
Maximum speed: 103 kn (119 mph, 191 km/h) ::
PL-12U 112 kn (129 mph; 207 km/h)
Cruise speed: 95 kn (109 mph, 176 km/h) at
75% power at Sea level ISA
PL-12U 102 kn (117
mph; 189 km/h)
Stall speed: 52 kn (60 mph, 96 km/h) flaps
down
PL-12U 50 kn (58 mph;
93 km/h)
Never exceed speed: 180 kn (210 mph, 330
km/h) :: PL-12U 150 kn (170 mph; 280 km/h)
Rate of climb: 600 ft/min (3.05 m/s) ::
PL-12U 4.066 m/s (800.4 ft/min)
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[**https://www.airliners.net/aircraft-data/transavia-airtruk-skyfarmer/379**](https://www.airliners.net/aircraft-data/transavia-airtruk-skyfarmer/379)**Transavia Airtruk & Skyfarmer**
The Airtruk
and Skyfarmer owe their origins to New Zealand's first
commercial aircraft, the Waitomo Airtruck. The original Waitomo
Airtruck was designed by Luigi Pellarini in the mid 1950s, and
used a number of components from the North American T6
Texan/Harvard series of piston engine military advanced
trainers. These components included main undercarriage wheels,
the front undercarriage assembly, fuel tanks and the 410kW
(550hp) Pratt & Whitney R1340 radial piston engine. The
Airtruck also featured a fairly tall and squat fuselage that
accommodated a pilot, two passengers and a chemical hopper,
tricycle undercarriage, a high mounted wing and boom mounted
twin tails. The unusual twin tail configuration was adopted as
it solved the problem of chemicals contaminating the rear
fuselage, while it also allowed easier loading of the chemical
hopper. The Airtruck first flew on August 2 1960. The Airtruck
was not built in New Zealand, and instead was further developed
in Australia by Transavia as the PL12 Airtruk. The Airtruk
differed from the Airtruck in having a flat six Continental
engine and additional lower stub wings. It was delivered from
December 1966. The PL12U utility seats five and has the chemical
tank deleted. It was delivered from 1971. The T300 and T300A
Skyfarmers are improved developments of the PL12 with a Textron
Lycoming IO540 engine; the T300 first flew in July 1971, the
T300A, which introduced aerodynamic improvements, first flew in
1981. The final development was the 300kW (400hp) flat eight
IO720 powered T400, four were delivered to China. Production
ceased in 1993.
Powerplants
PL12U - One
225kW (300hp) Continental IO520D fuel injected flat six piston
engine driving a two blade constant speed McCauley propeller.
T300A - One 225kW (300hp) Textron Lycoming IO540 fuel injected
flat six driving a three blade constant speed Hartzell prop.
Performance
PL12U - Max
cruising speed 188km/h (102kt). Initial rate of climb 800ft/min.
Service ceiling 10,500ft. Range with max payload 1205km (650nm),
with max fuel 1295km (700nm). T300A - Max speed 196km/h (106kt),
max cruising speed (75% power) 188km/h (102kt). Initial rate of
climb 515ft/min. Service ceiling 12,500ft.
Weights
PL12U - Empty
830kg (1830lb), max takeoff 1723kg (3800lb). T300A - Typical
empty 955kg (2100lb), max takeoff (ag category) 1925kg (4244lb).
Dimensions
PL12U - Wing
span 12.15m (39ft 11in), length 6.35m (20ft 10in), height 2.79m
(9ft 2in). Wing area 23.5m2 (252.7sq ft). T300A - Wing span
11.98m (39ft 4in), length 6.35m (20ft 10in), height 2.79m (9ft
2in). Wing area (including lower stub wing) 24.5m2 (264.0sq ft).
Capacity
Single pilot
in all versions. PL12, T300 and T400 - Seats for two passengers
and fitted with a chemical hopper. PL12U seats five with no
hopper.
Production
Total
production of 120 plus, including 18 assembled in New Zealand.
Production complete.
Related Links
Transavia
Airtruk & Skyfarmer
The backbone
of this section is from the The International Directory of Civil
Aircraft by Gerard Frawley and used with permission.
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**Patents**
****US4030688**-- IMPROVEMENTS IN AND RELATING TO AIRCRAFT STRUCTURES**
**[ [PDF](http://rexresearch.com/PellariniAirtruk/US4030688A.pdf) ]**
This present
invention relates to subsonic aeroplanes, of any subsonic speed
potential or of any size and use, which are endowed with a much
greater economic potential than equivalent aeroplanes presently
known, of equivalent size and power. As these aeroplanes, which
form the object of the present invention, are endowed also with
a different configuration as compared to known aeroplanes, they
are called airdynecrafts, for distinction. The airdynecraft's
new configurations and high economic potential are obtained by
using known components most of which perhaps are common to any
other existing aircraft, which components however are assembled
in one final unit according to a new design pattern so as
ultimately to obtain a flying craft capable to exploit more
efficiently the potential energy that it carries and able also
to comply more accurately with the first degree of flexibility
of the atmospheric environment than the already known aircraft
types The main advantages of the airdynecraft of the present
invention, as compared to the same category of payload
capability aircraft of current standard design, ares (1) Total
utilisation of fuselage volume; (2) Less structural penalty (due
to aero-elastic fatigue); (3) Embodiment throughout of fail-safe
concepts at no weight penalty (4) Greater safety in emergency
Take-Off-Landings (5) Comparatively much smaller overall
dimensions and empty weight and therefore manufacturing cost;
(6) More centralised thrust line with power-plant acting at rear
of the fuselage; (7) Minimum shift of centre of gravity from
empty to all up weight arrangements due to triangular
distributions of payload into the delta planform fuselage; (8)
Relatively smaller mass inertia about co-ordinates Y and Z; (9)
Less wetted area to lift area ratio therefore max. substantially
enhanced (C^ is the co-efficient of drag; and Cis the
co-efficient of lift);
(10) Smaller
wing loadings relative to wetted area and aspect ratio; (ID Less
power required relative to payload and reduced operating cost;
less noise and pollution;
(12) Intrinsic
antiauto rotation characteristic due to fuselage lift above
centre of gravity; (13) Increased payload to structural weight
ratio, (due to self lifting fuselage); (14) Softer and shorter
Take-Off-Landings due to forward wing and fuselage cushion
ground effect;
(15)
Substantial total lift gain due to fuselage in spite of the
airflow momentum losses due to tandem wings in cascade of
airfoils;
(16) Enhanced
total lift due to forward wing lift and power plant thrust
relationship; (17) Approximate spanwise eliptical distribution
of overall lift; Less yawing and rolling unbalanced moments
inthe event of engine failure; (19 Minimum structural damage in
emergency landings; (20 Multiplicity of common and
interchangeable components of comparably small size (economy);
(21 Sectional fuselage in smaller size aircraft (manufacturing
economy); (22 Larger useful floor areas for payload (passengers
and/or cargo); (23 Versatility of use; (24 Panoramic vision
(small size aircraft)? (25 Clean lifting surfaces free from
engine presence (lower wing drag); (26 Shorter undercarriages;
(27 Protection of engines from birds and debris - fire hazard
greatly reduced; (28) Life saving factor unparallelingly high
even in the event of landings on water. In one broad form the
invention comprises an airdynecraft provided with a streamlined
delta planform shaped fuselage, longitudinal airfoil sections
which c&n vary their camber, two shoulder wings, in tandem
and cascade at negative angles of incidence in respect of the
zero lift angle of the fuselage, and a power plant system,
located wholly or partly on top of the rear section of the
fuselage^ said fuselage also carries internal compartments for
payloads which are devised and arranged in accordance with both
the planform tapering and the flying attitude (angle of attack)
of the airdynecraft. In another form the airdynecraft comprises
a narrow delta or approximately delta planform fuselage with a
parabolically streamlined nose whose longitudinal section
contours form low drag high lift aerodynamic airfoils of
variable camber (and therefore of variable aerodynamic
characteristics), said delta planform fuselage carrying two
comparatively small-span shoulder type wings, in a close tandem
set and in a narrow cascade of airfoils, whose mean aerodynamic
chords form small positive angles, or even negative angles of
incidence in respect to the zero-lift incidence of the fuselage
mean aerodynamic chord and said delta fuselage carries the full
power plant system or a portion of it above its upper skin, and
as far as possible rearward in respectto its centre of gravity.
In the accompanying drawings which are shown merely by way of
example and illustration, two preferred forms of embodiments of
the present invention approximately at the beginning and at the
end of a vast range of intermediate practical applications in
accordance with payloads and speeds are shown. The invention and
its advantages shall become clearer from the following
description with reference to the accompanying drawings in
which: Figures 1, 2 and 3 represent basic views of an embodiment
of the present invention? Figure 4 is a floor view of the above
embodimentFigure 5 shows a longitudinal section of the above
embodiment in taxiiing attitude and/or in emergency landing
attitude?Figure 6 shows a fuselage according to this invention
made by component parts; Figure 7 shows a schematic view of an
embodiment of the airdynecraft showing relative forces produced
by the thrust of the power plant located at the rear of the
fuselage; Figure 8 represents a partial longitudinal section of
a common leading edge slot as it is found in both wings; Figures
9, 10 and 11 are three orthogonal views of another embodiment of
the invention showing a larger airdyne- craft of high subsonic
speeds, with 400 to 450 passengers capacity and two jet engines
as the power plant; Figure 12 is a floor view of the
airdynecraft of Figures 9 to 11; and Figure 13 is a longitudinal
section of the rear portion of the larger airdynecraft. The
airdynecraft as envisaged herein is endowed with the highest
possible speed potential, appropriate to its use and magnitude
of power installed, so as to achieve maximum flying efficiency
and at the same time is endowed also with the design
characteristics essential for the attainment of the lowest
possible take-off and landing speeds, as desirable for the
attainment of the highest safety factor possible. Both these
high and low speed potentialsalthough in contrast to each other,
are coexisting, in the airdynecraft, to an unparalleled degree
of efficiency, since its total wetted area to usable volume
and/or floor area ratios are the minimum and its usable lifting
area to total wetted area ratio is the maximum that are
attainable, relatively to aspect ratio adopted, irrespective of
whether these ratios are comacent pared against those pertaining to
known aircraft of low orhigh subsonic speed,characteristics; and
these fundamentally important ratios characterising any aircraft
type, together with the ratios C/Cand C3/C2 (which are also
partially dependent from them) essentially represent the basic
factors from which, ultimately, flight economy strictly depends.
In its frontal view, the airdynecraft may appear to be
associated with an excess of air resistance, in spite of its
well streamlined frame components; however its frontal view
misleads grossly if it is being evaluated as a drag producing
factor. In fact provided that the aircraft fuselage 1, and its
wings 2, 3 (forming a single body) change very gradually in
cross-sectional area and longitudinal profile and provided that
the longitudinal rates of change of the width and depth of the
fuselage, occurring under the wings (in a cascade of airfoils),
balance each other appropriately so as to blend gently with the
gradually increasing or decreasing rates of change superimposed
by the wings (thus minimising the losses in the airflow momentum
for vorticity and swirl which may be induced by any abrupt
acceleration of local masses of fluid), then the aerodynamic
drag of the aircraft would be zero, if it were invested by a
fluid hypothetically inviscid and incompres ible and its
attitude were such of producing neither positive nor negative
lift. This zero drag condition (relative to the above- mentioned
assumptions) would persist, irrespective of its cumbersome
frontal appearancesince the airdynecraft, characterised by the
streamlined features above described, conforms strictly to the
geometric rule embodied in the equation of fluid motion, due to
Laplace, i.e.3a4JjLf--f = o; This invention
relaces to aircraft of any speed, size and use, which are
endowed with enhanced safety and performance, as compared to
conventional existing aircraft of equivalent payload and
power, in virtue of the herein described features. As these aircraft look
different, they will be called airsymbiocraft; but within this
description they are called symbiocrafts, for short.
2) Prior Philosophy This invention,
basically, is an amelioration of the symbiotic philosophy
that the ght Brothers have embodied in their canard-biplane.
They must have thought that mechanical flight does net
necessarily have to simulate the flight of living beings
(which are bestowed with limited velocity) and consequently
they devised a truly revolutionary aircraft whose
configuration had enabled them to fly safely before ii I\_
anyone else. However, since this application consists of a
number of complementary new ideas that improve consistently
the basic concept of the Wright Brothers, then even this
application should form zn invention in its own right.
It may seem paradoxical to pursue substantial improvements
through a recourse, for inspiration, to biplane philosophy
(long ago discarded in favour of the monoplane philosophy,
which has become so familiar) nevertheless the fact is that,
if the aircraft engines of the sixties were made available
in the thirties, to enable the biplanes to fly efficiently
at high tropospheric altitude, then the aircraft C
development would have occurred in accordance with the
canard biplane concept, which, at very high altitude, S g\*
is more aerodynamically convenient than the monoplane \*e
concept.
C Many experts share the conviction that the present
conventional monoplanes have reached their top limits of
safety, performance and economy and do not foresee any
substantial economic advantage in their further development
as monoplanes.
Even large aeronautical companies are involved in research
for alternative solutions more advantageous than those of
the present conventional monoplanes, J -3since even them
judge that these monoplanes have reached a stumbling block,
from the performance and economy viewpoint, despite the
great achievements in propulsion, aerodynamics, structures
and systems, made in the U.S. in the last fifty years.
Thus, by representing one of the most advantageous
alternatives, the symbiocrafts should find a worthwhile area
of application, in both civil and military aircraft fields
as, in reality, nothing wrong has emerged by adapting to the
symbiocraft the inspired concept of the canard biplane of
Orville and Wilbur Wright, who have invented the mechanical
means more convenient to fly safely and more eccnomically.
3) References and Experimental Findings in Unconventional
Art:
0 0 a) FLYING WING AIRCRAFT characterised
by: Simplicity, but low operating efficiency; low volumetric
efficiency;
lack of rotational angle of incidence
in take-offe 5 landing; small wing loading; mediocre
potential of development.
b) MULTIPLE FUSELAGE AIRCRAFT characterised by:
Sufficient operational efficiency and good development
potential but Jack of speed potential; excessive spanwise
mass inertia; absence or difficult intercommunication.
7 -4c) LIFTING BODY AIRCRAFT characterised by: Insignificant
operational efficienty; very low empty weight but of no use
at subsonic speeds, if it is exploited alone.
d) SPANLOADER AIRCRAFT characterised by: Mediocre
operational efficiency; lack of speed potential;
mediocre volumetric efficiency; excessive lateral intertia;
poor flying performance especially in takeoff/ andings; only
apparent both simplicity and small empty weight.
15 e) AIRDYNECRAFT (as per above U.S. Patent 4 030 0 68)
characterised by: Good operational efficiency;
good volumetric efficiency; low empty weight, acceptable
mass inertia on all three orthogonal axis; good flying 5
performance.
However: a large scale radio controlled model of the
airdynecraft, during it reiterated flights in performing
take-off/landings has manifested a 20 degree of potential
danger, which was not evident in the wing-tunnel testings
previously made with smaller mcdels. Such potential danger
was due to adverse effects of the ground air-cushion,
because of rotational peculiarities at take-off stage, since
above a height of 2-3 times its wing m.g,c. from the ground,
the model behaviour was very good and and comparatively
competitive.
To get rid of such serious handicap were required various
design alterations, starting from a gradual reduction of the
main-plane aspect ratio of the model, and arriving to a
stage in which the above mentioned U.S. Patent 4 030 688,
was definitely superseded by the present concept embodied in
this invention for which application now is made under the
name of "Symbiocrafts".
\*4 30 4) Comprehensive Principa Advantages of the U.
Invention:
A new configuration and a particular
type of structure providing greater and more chances of
safety in general (and in particular during S\* emergency
landings on rough grounds or water).
0 U A configuration more suitable to carry simultaneously 35
passengers and more luggage (if the carrier is small), or a
greater number of passengers and large or heavy cargo, (if
the carrier is comparatively large), while providing maximum
volumetric and structural efficiency for both types of
payloads.
A configuration more suitable to cruise at higher jl I
-6altitude, hence more economical cruising.
A configuration comparatively shorter and packed;
which leads to symbiocrafts of comparatively small weight
and mass inertia; therefore more suitable for further
development in size and payload capacity; without imposing,
for many years ahead, extensions or additional airport
tarmacs or runways. In fact, the symbiocrafts can perform
take-off/landings from runways no longer than those needed
for conventional ~aircrafts capable of carrying only half
the maximum payload carried by symbiocrafts of equal o\*9
length. Therefore, the present airport runways S could
remain adequate until the volume of airo traffic is much
greater, (should the symbiocrafts be used).
f 10 5) Clarification concerning the description of the
Symbiocrafts
Having found that the present invention is consistent and
useful even if it applies to very small and slow
symbiocrafts flying at relatively low altitude as well as it
applies also to supersonic aircraft in general, wherein the
velocity becomes imperative in determining their
configuration and type of structure, the description of the
invention IJ -7that follows will refer separately to small,
large and supersonic symbiocrafts, so as to simplify the
task of explaining them.
B) SUMMARY OF THE INVENTION Various short-comings of the
known aircraft designs have been resolved by the present
invention by providing new arrangements of aircraft
components and new configurations which suit most of the
civil S\* and military aircraft, irrespective of whether they
Are small or large, subsonic or supersonic.
The subsonic symbiocrafts, in fact, comprise a a lower and
an upper-mainplane which are held together a by a pair of
fins and rudders and a central air-streamlined pilon in
manner to form an aircraft with rolling, directional 25 and
pitching stability and maneuvrability; wherein the
lower-mainplane is similar to a blunt wedge, whose
longitudinal sections form thick contours of low drag
airfoils; while the upper-mainplane is more or less similar
to a conventional wing of fast characteristics and great
aspect ratio; hence of great lifting potential.
Therefore the main function of the lower-mainplane in the
context of this invention, is to provide larte amounts of
useful space for payload and fuel and also to provide an
efficient basic structure for the whole symbiocraft; while
the main function of the upper-mainplane -8is the generation
of economical lift and good performance.
The supersonic symbiocrafts, has a configuration broadly
similar to that above described, except that ooth its
mainplanes, in this case, are endowed with supersonic
characteristics; hence both of them are endowed with small
span and small thickness ratio; thereby the payload is
carried by a slander fuselage which is supported by either
the upper or the lower mainplane; but preferably by the
upper-mainplane, so as to make the lower-mainplane housing
the power plant and undercarriage away from a a a the
fuselage.
e S\* The invention, especially when it refers to large
symbiocrafts, may also include two approximately horizontal
winglets protruding from the top-rearsides of the
lowermainplane and extending outwardly to receive and
structurally connect at their tips two fin and rudder units,
which C extend upwards until they reach, or surpass, the
bottom skin of the upper-mainplane sides so as to
structurally connect them with the lower-mainplane sides;
and may S extend also downwards, so as to support an engine
on each side of the lower-mainplane; thus forming part of
the main central power-plant system of the symbiocrafts,
when so it is preferred or necessary. Besides, such winglets
would increase the aspect ratio of the lowermainplane.
The invention, furthermore, includes a power-plant system
formed by a single, or a group of propulsive engines
concentrated in proximity of the vertical plane of symmetry
of the lower-mainplane, near its trailing edge, and may be
fully exposed or housed into the body thickness of the
trailing edge of the central portion ot the lower-mainplane.
The power-plant, or portion ot it, may also hang trom the
upper-mainplane; especially an small symbiocrafts or on
supersonic ones.
S\* The invention also comprises a canard surface, protruding
from the sides of the nose of the lower-mainplane,
preferably attached to its bottom; said surface being
characterised by its relative smallness in span and area;
hence lightness and simplicity.
20 The invention also includes symbiocrafts with a main
under-carriage at a rearward station behind the
symbiocrafts' centre of gravity and located underneath of
the lower-mainplane, and inwardly from its leading edges and
trailing edges, at a sufficient distance from them so as to
allow its full retraction into the two sides of the
lower-mainplane body; the said under-carriage comprising a
train of two or more legs each side, which carry two or more
coaxial wheels endowed with trailing deflection and
retraction.
Another part of the present invention is a set of two
mainplanes forming the lifting surface of the large
symbiocrafts one high above the other and staggered in
respect of the symbiocraft C. of G. according to their
different sweep-backs, which are complemented by two slender
components laying longitudinally between them, in their
symmetrical plane, and structurally holding two central
pilons, instead of one, in order to increase the strength
and stiffness of the symbiocraft and make it more suitable
as a two or more stages air-space vehicle as shown by the
attached drawings.
The invention also includes a lower-mainplane, 35 for large
subsonic symbiocrafts, whose body is formed by two
swept-back symmetrical side bodies plus one or more central
interbodies; all of which, in their turn, 0 can be
subdivided in adjacent compartments or lobbies for
passengers or cargo so that, the compartments for passengers
are fully inter-communicating, while the 0, compartments for
cargo are endowed with the unique feature of a continuous
and simultaneous loading and unloading of a cargo (without
reverse motion) and yet both entry and exit are being
located At the very end of the two sides of the
airsymbiocrafts; thereby making the symbiocrafts \*000 more
suitable for carrying many very large roadable vehicles, (if
so required), or more cargo each fiiynt.
Still another aspect of the invention is a lower mainplane
of great thickness ratio sufficient to obtain a blunt
leading edge for the application of powerful forward slats
so as to enhance its lifting effect due 1- 11-to the ground
cushion of air in take-off or landing stages; thereby
reducing the take-off run or sot teninq the landing impact
of the symbiocraft; hence ;tro i I(ng 1 k reliet tor its
structure and its under-carriage.
A further part of the invention consists; in a lower
mainplane whose relevant thickness ratio allows exploitation
of most ot the internal partition walls as, S;tructural
members; furthermore provides the high torsional stiffne;s
and strength required for holding the upper-mainplane at the
best level required for having the two mainplanes producing
and transferring to one another the best of the aerodynamic
and stressing effects that are appropriate to each of the
two mainplanes.
And again a part of the invention consists in two mainplanes
forming a biplane wherein the upper-mainplane generates lift
and drag nearly at the rate fitting a two dimensional
airflow shile, instead, the lower-mainplane generates lift
and drag at the rate of a strong three dimensional, (or
vertical) airflow; hence insignificant aerodynamic
interference and well rounded lifting curve of the
symbiocraft (particularly important at take-offlanding
speeds).
In conclusion, this invention represents the result of
research carried out with the flying model made in
accordance with the previous U.S. Patent 4 030 688, -122 now
abandoned, as mentioned above...
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