Magnus Aerospace Corp. - hybrid spherical airshipPeter Lobner, updated 9 March 2022
1. Introduction
The LTA 20-1 was a spherical, heavy-lift, hybrid airship designed in
the early 1980s by Magnus Aerospace Corporation of Ottawa,
Ontario, Canada. The LTA 20-1 combined three sources of lift:
aerostatic lift from helium, dynamic lift from vectored thrust engines,
and aerodynamic Magnus lift from the spherical hull rotating with abackspin. The craft’s structural weight, including engines, gondolaand sphere, were fully supported by the aerostatic lift.

Magnus Aerospace Corp. promotional brochure cover.
Source: J.D. Lowe, 30squaresofontario.blogspot
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12. Magnus effectMagnus Aerospace Corp used theaccompanying diagrams to explain
how their airship generates
Magnus lift.
Figure A shows airflow around a
non-rotating sphere. Airflow
separates equally from the top andbottom, near the midpoint of thesphere. No lift is generated.
Figure B shows airflow around asphere rotating with a backspin.
The top of the sphere rotatesaway from the direction of travel.
Flow remains attached longer tothe top side, speeding up theairflow. Interference at the bottomcauses earlier flow separation.
The airflow velocity difference
between top and bottom and thedownward deflection of the wakeproduces Magnus lift.
Figure C shows the airflow arounda rotating sphere with a gondolasuspended by a yoke from theaxis of rotation. The gondolamasks the areas of interference
between the sphere and the freestream air, smoothing out the airflow. Air remains attached to the
top of the sphere as before.
Stability is enhanced by controlled
boundary layer shedding at theback of the gondola.
Source: Magnus Aerospace Corp.
promotional brochure
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The Magnus effect is a special case of the Bernoulli principle, applied
to a rotating cylinder or sphere. The effect was first described by theGerman physicist Heinrich Magnus in 1852.
Magnus lift is generated during LTA 20-1 forward flight, when there isa relative wind over the spherical hull. In cruise flight, total lift is thesum of aerostatic lift and Magnus lift from the rotating sphere. The
vectored thrust engines are not needed for lift during cruise flight andare positioned to produce thrust for forward flight.
During LTA 20-1 vertical takeoff and landing (VTOL) or hover, there
will be little or no relative wind and no lift is generated by the Magnus
effect. In this case, total lift is the sum of aerostatic lift and dynamic
lift from the vectored thrust engines.
As airship size increases, aerostatic lift increases with the cube ofballoon diameter, whereas Magnus lift varies with the square ofballoon diameter. As airship size increases, the relative contributionof Magnus lift decreases. At an envelope diameter of 160 ft (48.8meters), Magnus lift is able to generate about half of the “netdisposable static lift.” In even larger airships, Magnus lift will be
useful if it can produce about 30% of the net disposable static lift.
3. Magnus effect spherical airship patent
Magnus Aerospace Corp. filed several patents that describe thedesign and operation of their Magnus effect spherical airship. In thissection, we’ll take a look at US Patent US4366936A, “Aircraft havingbuoyant gas balloon.”••••

Inventor: Frederick Ferguson
Filed: 4 November 1981
Granted: 4 January 1983
Assigned to: Magnus Aerospace Corp., Ottawa, Ontario,
Canada• Available here:
https://patents.google.com/patent/US4366936A/en?q=magnus+airship&oq=magnus+airship

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With reference to patent Fig. 5, the non-rigid, non-elastic, sphericalgas envelope is designed as a superpressure balloon, operating atgreater than atmospheric pressure (up to 0.14 psig), with stabledimensions that are not substantially affected by atmosphericpressure and temperature. The envelope is connected to endplates(114) that secure the envelope and ballonet (124) fabric and connectto an axle (116). The patent described a continuous axle. Lateranalysis showed that the stiffness of the inflated envelope allowed theuse of exterior end axles that resembled the nose mooring device fora blimp. The endplates include ports for filling helium andoverpressure protection devices to vent helium. The axles of therotating envelope connect to the load support yoke (132) via bearingsat the tops of the yoke arms. The yoke carries the weight of thegondola (136), with the crew cabin (136b) and payload bay (136a),and the thrust vectoring main propulsors (140), and transfers thatload via the endplates into the fabric envelope.

Electric motors for rotating the spherical gas envelope are installed in
the fixed yoke. The rate of rotation is adjusted to the forward speed
to maximize the Magnus lift. At 60 mph, the rate of rotation is 3.5 rpm.
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4Magnus lift can be increased by the use of a non-smooth surface(i.e., a dimpled golf ball). Dimpling of the airship’s gas envelope canbe achieved with an arrangement of longitudinal and transverse
reinforcing cables (112), with pillowing of the envelope fabric in thesquare spaces between the cable intersections.
Aerostatic buoyancy and trim are controlled by the two air ballonets(124). When fully expanded, the ballonets have the shape ofhemispheres as shown in Fig. 5. The ballonets provide the solemeans for regulating the altitude of the airship. The maximum
altitude for unloaded flight was 15,000 ft.

With reference to Figs. 4 and 5, note that the shape of the yokeinterior surfaces and the gondola upper surface conforms closely tothe adjacent surfaces of the gas envelope. At its closest point, thegap between these surfaces is less than 2% of the balloon radius(gap less than 12 inches). This is done to limit airflow between theModern Airships

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yoke / gondola and the envelope and reduce aerodynamic drag bysmoothly deflecting airflow around the sides and under the gondola.
The main thrusters (140) are shown in their position for cruise flight.
Thrust deflectors in the exhaust slipstream (150) also can be used foryaw control. The main thrusters are shown as ducted fans, which
would have variable pitch propellers and thrust reversing capabilities.
The main thrusters rotate in a vertical plane through 200° to give theability to move the airship up or down, forwards or backwards androtate about the airship’s vertical axis.
Transitioning between forward flight and VTOL is accomplished byrotating the thrust vectoring engines (140) thru about 90° andcontrolling engine power as Magnus lift decreases as airspeeddecreases. The airship has dedicated side thrusters for direct lateralcontrol during precise VTOL and hover maneuvers.

Fig. 6 is a view from beneath the airship. The landing skids on thegondola (136) can be fitted with pontoons for landing on water.

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The patent provides the following basic specifications for two airshipmodels, designated 72P and 160P.

4. The sub-scale Magnus model airships
In the early 1980s, Magnus Aerospace contracted with the Universityof Toronto’s Institute for Aerospace Studies (UTIAS) subsonicaerodynamics group to study the aerodynamics of the LTA-20-1.
Over the span of several years, UTIAS tested more than 100 model
configurations in their wind tunnel. In addition, they built and tested
several small free flying models.

One of many wind tunnel models built and tested in theUTIAS wind tunnel. Source: J. Delaurier, et al., 1983

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In the same time period, Magnus Aerospace also contracted with ateam at Carleton University in Ottawa to build and test fly the 19-foot(5.8-meter) diameter model shown in the following photos. In test
flights, the model demonstrated that it could generate Magnus lift.
Later, it was used at Magnus Aerospace promotional events.

Subscale Carleton University model of the LTA 20-1.
Source: imgur.com
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8Subscale CarletonUniversity model testflight.

Sources: (above)
imgur.com.
(below) Magnus
Aerospace Corp.
promotional brochure

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Science & Mechanics magazine cover, Jan/Feb 1983, showing an
LTA 20-1 based on the design of the Carleton subscale model.

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Carleton subscale model looking large in forced perspective.
Source: Pinterest
5. LTA 20-1 business applications
Magnus Aerospace Corp. designed the LTA 20-1 to carry muchheavier payloads than helicopters over longer ranges and at much
lower operating cost per unit of lift ($/ton-mile). The LTA 20-1 designcould be scaled up to at least 100 tons of net payload.
It is capable of operating with only common ground infrastructure.
• A central mooring point under the gondola secures the airshipto the ground.
• The spherical gas envelope can be rotated on the ground,greatly simplifying inspection and maintenance.
• The airship is easy to assemble and disassemble.
• Once disassembled, it can be stored and maintained inconventional structures.
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11With its ability to hover, control lift, and transport heavy loads, theLTA 20-1 appeared suitable for the following business applications:• Logging• Transport heavy loads for any industry (construction equipment,marine salvage, remote installations)• Support resource development in remote areas by oil, gas andmining industries• Support offshore exploration activities• Support emergency response efforts• Transfer cargo to/from ships at sea to avoid port congestion• Transport military hardware and supplies
Logging
The LTA 20-1 gives the logging industry the ability to operate in steep
terrain without the need to develop access roads throughenvironmentally sensitive areas to get to the area being logged. Theairship also gives the industry the ability to target their operations
toward a specific variety and grade of lumber that matches current
market demand.

Rendering of an LTA 20-1 conducting logging operations.
Source: Magnus Aerospace Corp. promotional brochure
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12The Magnus Aerospace promotional brochure includes the following
general specification for a logging version of the LTA 20-1 with a 28
meter (99 feet) gas envelope.

Source: Magnus Aerospace Corp. promotional brochureThree view drawing of a turboprop-powered LTA 20-1 in logging
configuration. The tailplane primarily provides pitch damping.
Source: J. Delaurier, et al., 1985

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In 1985 Magnus Aerospace analyzed the dynamics of handling aheavy suspended load in turbulent air during logging and concluded
that “…translational velocity disturbances to the vehicle’s state caneasily be corrected with small displacements of the control surfaces.”

Rendering of a Magnus-type spherical airship conducting
logging operations. Source: imgur.com
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Pipeline construction support
As with logging, the LTA 20-1 can carry pipeline heavy equipment
and pipe sections as suspended loads and deliver directly to theconstruction site, which may be in a remote location that does nothave a transportation link by other means. The LTA 20-1 enables thework to be performed without having to build access roads throughenvironmentally sensitive areas.

Rendering of an LTA 20-1 assisting with pipeline construction.
Source: Magnus Aerospace Corp. promotional brochure
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Emergency response
The LTA 20-1 can carry relief supplies directly to the point of need,which may be in a remote area that lacks access to other modes oftransportation. In the case of a train derailment, the airship canoperate as a flying crane to recover heavy rail cars and facilitate
restoration of rail service.

Rendering of an LTA 20-1 assisting with recovery from a train
derailment. Source: Magnus Aerospace Corp.
promotional brochure

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Heavy cargo transport
The LTA 20-1 can be developed to carry heavy unitary cargo, suchas an armored military vehicle or large construction equipment, in acargo bay rather than as a suspended load.

Rendering of an LTA 20-1 transporting a military armored vehicle
on a cargo “shelf” behind the crew cabin.
Source: EIR Science & Technology, 1986
6. The end of the LTA 20-1, or was it?
In 1986, Magnus Aerospace planned to issue stock in Canada toraise the money to scale up, and was looking to affiliate with a major
aerospace manufacturer. Several foreign countries had expressedinterest in the LTA 20-1 heavy-lift technology. Japanese companies
C-Itoh and Nissho Iwai were interested in representing Magnus
Aerospace in the Pacific Rim.
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In spite of these prospects in 1986, a full size LTA 20-1 never wasbuilt. Magnus Aerospace Corp. is no longer in business.
Thanks to former consulting flight dynamicist to Magnus Aerospace,James Lowe, for preserving a copy of the LTA 20-1 promotional
brochure on his blog site:
https://30squaresofontario.blogspot.com/2014/02/400-posts-1-aboutblimps.html
7. Mars Magnus Aerobot (2010)
In a 2010 study at the Space Research Centre in the School ofEngineering at Cranfield University, Bedford, UK, a “Magnus LiftAerobot” that looked very much like an LTA 20-1 was proposed as aflying craft to operate in the rarefied atmosphere of Mars. Hydrogen
was to be the lifting gas. The study found, “Such a craft would require
a continuous power supply, undoubtedly requiring more energy thanthe solar panels could supply, resulting in a flight profile of shortduration airborne periods with frequent landings for battery charging.
A 10 m (32.8 ft) diameter aerobot could produce a net lift of 14.9 N(1.5 kg) in this way, ideal for a light weight science payload.”

The Mars Magnus Aerobot. Source: S. Ravindran, et.al, 2010
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You can read the Mars Magnus Aerobot paper here:• S. Ravindran, S. Hobbs & J. Jennings, “Mars Magnus Aerobot
Preliminary Design,” conference paper SpaceOps 2010,
Huntsville, AL, 25 – 30 April 2010:https://arc.aiaa.org/doi/pdf/10.2514/6.2010-2184

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198. For more information• J. Delaurier, “Preliminary report on the engineeringdevelopment of the Magnus Aerospace Corp. LTA 20-1 heavylift aircraft,” The Aeronautical Journal , Volume 87 , Issue 864 ,pp. 119 – 131, April 1983:
https://www.cambridge.org/core/journals/aeronauticaljournal/article/abs/preliminary-report-on-the-engineeringdevelopment-of-the-magnus-aerospace-corp-lta-201-heavyliftaircraft/B40B38A30E97F715904F8EBC47B26F7B• H. Scholaert, “Dynamic analysis of the Magnus Aerospace
Corporation LTA 20-1 heavy-lift aircraft,” Conference paper,
AIAA 5th LTA Conference, Anaheim, CA, July 1983, published
online 17 August 2012: https://arc.aiaa.org/doi/10.2514/6.19831977• J. Delaurier, W. McKinney, W. Kung, G. Green & H. Scholaert,“Development of the Magnus Aerospace Corporation's rotatingsphere airship,” Conference paper, AIAA 5th LTA Conference,
Anaheim, CA, July 1983, published online 17 August 2012:https://arc.aiaa.org/doi/10.2514/6.1983-2003• J. Delaurier, W. McKinney, J. Lowe, D. Uffen & A. King,“Progress Report on the Engineering Development of theMagnus Aerospace LTA 20-1 Airship,” American Institute ofAeronautics and Astronautics, paper 85-0876,1985:
https://arc.aiaa.org/doi/10.2514/6.1985-876• J.D. Lowe, “An investigation into the hovering behavior of theLTA 20-1 airship in calm and turbulent air,” American Instituteof Aeronautics and Astronautics, paper 85-0878,1985:
https://arc.aiaa.org/doi/pdf/10.2514/6.1985-878• David Cherry, “The Heavy Lift Vehicle That’s Lighter Than Air,”EIR Science & Technology, Vol. 13, No. 23, 6 June 1986:
https://larouchepub.com/eiw/public/1986/eirv13n2319860606/eirv13n23-19860606_020the_heavy_lift_vehicle_thats_lig.pdf• J.D. Lowe, “400 posts; 1 about blimps,” (this post includes a
copy of the Magnus Aerospace Corp. LTA 20-1 promotionalbrochure), 5 February 2014:
https://30squaresofontario.blogspot.com/2014/02/400-posts-1about-blimps.html

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• “LTA-20/Magnus Spherical Airship,” 17 January 2020:
https://imgur.com/gallery/dNUNz9W
Other Magnus Aerospace Corp. patents• European patent application EP0078713A2, “Aircraft Having
Buoyant Gas Balloon,” filed 3 November 1982, published: 11
May 1983: https://data.epo.org/publicationserver/document?iDocId=114658&iFormat=0
Other Modern Airships articles• Modern Airships - Part 1: https://lynceans.org/allposts/modern-airships-part-1/• Modern Airships - Part 2: https://lynceans.org/allposts/modern-airships-part-2/• Modern Airships - Part 3: https://lynceans.org/allposts/modern-airships-part-3/

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