The Helicostat was described as a helicopter in which the vehicle weight is nullified by two balloons arranged in a catamaran fashion. Development of such a vehicle is discussed, and various uses for these helicopters are summarized

Morisset, J.

English

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NASA TECHNICAL MEMORANDUM NASA TM 75063
 
A NEW HELICOSTAT FROM SNIAS HELICOPTER DIVISION
 
J. Morisset
 
(NASA-T--75063) A NEW HELICOSTAT FROM SNIAS N78-18041 
HELICOPTER DIVISION fNational Aeronautics 
and Space Administration) 15 p HC A02/MF 
A01 CSCL 01C Unclas 
G3/05 05482 
Translation of "Cinquante ans Apres: Le
 
Nouvel "Helicostat"._ Airet Cosmos-, NO.65, 
Jan. 8, 197Lnpn 19-22 and 40. . 
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
WASETNGGTON,- D-C. 2- ECEBE-L5576--- 1977 
https://ntrs.nasa.gov/search.jsp?R=19780010098 2020-03-22T05:58:14+00:00Z
STANDARD TITLE PAGE 
I. Report No 2 Government Accession No 3 Recipient's Catalog No 
NASA TM 75063 1


4 Title and Subtitle 5 Report Date 
A New Helicostat from SNIAS Helicopter December. 1977


6 Performing Orgon,zaton CodeDivision 
 
7. Author(s) 8 Performing Organization Report No 
J. Morisset


10 Work Unit No 
11 Contract or Grant No 
9 Performing Organization Name and Address NASw-2791 
SCITRAN 13 Type of Report and Period Covered 
Box 5456 
Santa Barhra CA (1nR Translation 
12 Smansonng Aoency Nome and Address 
ational Aeronautics and Space Administration


Washington, D.C. 0546 14 Sponsoring Agency Code 
15 Supplementary Notes 
Translation of "Cinquante ans Apres: Le Nouvel "Helicostat" 
Air eT~osmnos, No. 653 _!Jan. - _977, . 19-22 and-40. 
16 Abstract 
The Helacostat can be viewed as a helicopter in which the


vehicle weight as nullified by two balloons arranged in a


catamaran fashion. Development of such a vehicle, the pro­

totype of which could fly in two years, would involve a verr


low technological risk since a market has already been iden


tified.


ORIGINAL pAGB IS 
OF poor 
17. Key Words (selected by Author(s)) 18 Distribution Statement 
Unclassified - Unlimited


19 Security Classif (of this report) 20 Security Closs, f (of this page) 21. No. of Pages 22 Priee 
Unclassified Unclassified _15


HELICOSTAT FROM SNIAS HELICOPTER DIVISION


History, it is said, is an eternal new beginning, a new illustra- /19


tion of this adage has just been given by Aerospatiale through its He­

licostat project, a hybrid machine - half balloon, half helicopter ­

which was recently the object of a press conference at the Bois Tech­

nical Center 1 .


The new machine is in reality the distant son of the helicostat


of Etienne Oehmichen, a French engineer born in Chalons-sur-Marne in


1884 and who remains for historians of aeronautics the first to have


succeeded on May 4, 1924 - more than 52 years ago - in making a stable


helicopter fly over a one-kilometer closed circuit in Valentigney, in


the Doubs Department. The machine used, the second built by the French


pioneer, weighed 1100 kilograms. It was equipped with a 180 HP rotary


engine driving twelve propellers or rotors designed to insure susten­

tation, translation, and direction.


The First Helicostat


But CEhmichen, a tenacious engineer and a first-class theorist,


was a born researcher, his tests had convinced him that it was diffi­

cult to stabilize a helicopter without using complex methods.(his No.


2 helicopter owed part of its stability to an actual gyroscopic fly­

wheel provided by the rotary engine that was used.) Therefore, he


built a theory on the stability of machines with rotating airfoils that


was remarkable for that time in history. While the Marquis Pateras


Pescara was able to make fly+ , with difficulty, the first helicopter


with counter-rotating rotors equipped with two control devices that


*Numbers in margin indicate pagination in foreign text.


1 See Air et Cosmos, issue #650.


t in 1923 and 1924 at Issy-les-Moulineaux.


1 
were universally adopted later.


-qv\ 
4::1SORIGINAL PAG I 
~4OF POORQUJh 
Chmichen was attempting to show that there was a simple means of auto­

matically stabilizing the helicopter, raise its center of gravity and


its center of pressure ("bound volume" effect) by equipping it with a


balloon inflated with air and placed above the rotors.


Evidently, such a balloon did not take part in sustentation and


therefore only had a stabilizing effect. In reality, the first craft,


3
tested on January 15, 1921, actually had a 100 m lifting balloon


built by Zodiac and designed to lighten the entire assembly by 70 kg,


as the Dutheil-Chalmers 25 HP engine was inadequate to lift CEhmichen's


No. 1 helicopter which weighed 370 kg. Three of the later craft (CEh­

michen built at least a total of seven) were true "Helicostat" in the


sense intended by their creator; that is, craft rising thanks to lif­

ting rotors but lightened by a balloon inflated with hydrogen.


As early as 1931, CEhmichen had mastered the problem perfectly,


his fourth machine, topped with a spindle-shaped 550 m3 envelope built


by Zodiac, flew at Orly, demonstrating total maneuverability, a key to


2


very good safety. It was equipped with a 40 HP Salmson engine driving
 

two tractive propellers with variable and reversible pitch, and two


propellers with slanted shafts. Two hundred hours of flying were com­

pleted in that fashion in all types of weather. Fifty percent of the


lift was obtained thanks to 400 m3 of hydrogen.


In 1932 the second Helicostat by CEhmichen appeared, built with


the assistance of the aeronautical equipment company, "Claude et Hatton".


We can ask ourselves, 45 years later, why the formula was never adopted.


Potential users, the army primarily, undoubtedly had their attention


monopolized by the large dirigibles and by the first promising tests


of autogyros by Juan de la Cierva. Thus, the first generation helico­

stat disappeared, even though it was the simplest rotary wing aircraft.


It could have led to the creation of a family of mixed "balloon-helicop­

ter" craft offering numerous possible combinations of lift distributions


between the rotors and Archimedes, principle and much easier to use than
 

classical "dirigibles". The reappearance of the balloon + rotor combi­

nation in the shape of the new A6rospatiale Helicostat (let us mention


that Agrospatiale makes reference to Chmichen's work) is the indirect
 

consequence of the movement toward lighter-than-air craft that has been
 

taking place over the last years. In France, this has materialized


with the creation of the "Association d'Etude et de Recherche sur les


'Aeronefs Allgs"* or Arall. The November 1973 symposium organized


in Paris by Aerall was the point of departure of a "high interest move­

ment". In 1975, ONERA and Aerospatiale released information on the


Obelix" project2 , a multiballoon craft equipped with eight helicopters


rotors ("Super Frelon") and capable of lifting 500 tons. E.D.F., we


remember, was studying the problem of transporting and installing


large tanks for its future nuclear power plants.


The "0belix", like other projects (let us mention in particular


the lenticular dirigible "Titan" by M. Balaskovic) sinned, however,


in one direction: gigantism. The necessary funding was large, risks


were not negligible and E.D.F. was in a hurry. Therefore, we no longer


talk, temporarily perhaps, of the "Obelix" project, but the idea has
 

been launched and the small working groups formed around these projects


2Air et Cosmos, nos. 563 and 564.


3 
---- ----------------
e= Winch, --%atable\
 -
p'nj] 

The new Helicostat proposed 1 n Inflatable 
by Aerospatiale combines - Landing 
3
two 1500 m balloons and a Cushion


"Dauphin" helicopter rotor. )t"t


Overall span: 36.5 m, t


Height, 12 m; length, 26 m. -'


Such a machine is proposed 0 .-.


to transport logs from for- t' F I-t _ Lycominf 
 
est areas with difficult <IGSO-30-AID 
access. Payload. •2-3 tons . ,' Engine 
- - i , o ," 
ORIGINAL PAGE 18 
OF POOR QUAIXJT 
4 
Lifting device with a 
V ,17-ton capacity; the 
" -- -.		 rotors are those of the
 

"Ecureuil" helicopter.


Total weight: 30 tons.


Span, 40 m. Height, 33.5


m. Length: 71 m.


5 
have had the merit of clearing up the problems.


A Need. Removing Logs from Forest Areas


Meanwhile, (in June, 1975) experimental flights performed in the


Isere Department with a "Lama" crane-helicopter belonging to Aero­

spatiale had shown the advantage of using helicopters to clear logs;


that is, to transport felled trees (in areas difficult to reach) to 
 
the road network. For a lack of cablemen, cable systems used to carry


logs over forests were gradually disappearing, particularly since


their cost of operation was too high.


The number Four craft by Etienne (Ehmichen was the first


to bear the name of "Helicostat". Between 1929 and 1931


it completed 200 flying hours, including a 30 minute de­

monstration hovering at an altitude of 300 meters, no-power


landings and stable flights with the control stick released.


Fifty percent of the lift was provided by two tiltable


rotors driven by only a 40 HP engine. The other half of


the lift was provided by 400 cubic meters of hydrogen.


350,000 Tons Per Year


Now, large quantities of timber are available from mountain fo­

(at least 350,000 usable tons annually). This timber is left
rests 
 
in the forest when forestry preservation (timber that is not removed


rots and the forest degenerates) and our balance of payments should


induce us to exploit all forest areas. By recovering each year 350,­

000 additional tons of lumber, we would save 0.35 billion francs, or 
nearly 50% of imported fir and pine lumber. 01IGINAL PAGE IS 
OF pooR QUALM 
6 
/21 
The situation is the same in many countries: Switzerland 240,­

000 to 1,000,000 tons per year; Austria, 280,000 tons per year; Nor­

way, 1.6 million tons per year, etc. Experiments conducted with the


"Lama" have shown that the latter was superior to cable systems in


spite of the handicap of the relatively small load sling-lifted (900


kilograms). At the end of 1976, more than 6,000 tons of timber had


been removed in that fashion in the province of Haute-Savoie, then in


the province of the Pyrenees Atlantiques, but the situation would be


even better if the cost of lumber removal by air could be reduced and


if cutting large logs into smallersections could be avoided (need


for a higher load-carrying capacity).


From this came the idea to apply the work performed by the "Aero­

spatiale study group for aerostatic machines"-to build a light-weight


machine capable of lifting 2 to 3 tons. By seeking to optimize the


"balloon + rotors" combination, engineers finally arrived at a hybrid


machine that we can consider as a dirigible with lift and maneuver­

ability characteristics greatly increased by a helicopter rotor, or as


a helicopter with its own weight counterbalanced by balloons which


would evidently make it possible to increase the lift capacity by that


amount.


New Formula


Correctly named "Helicostat" (even if its definition does not


exactly match CEhmichen's concept) the machine proposed by Aerospatiale


would be even easier and more economical to build as we have made an


effort to use a maximum number of low-cost and existing components.


The technological risk appears to be virtually nil and so does the


industrial risk, since the demand - which already exists - has been


identified; only the building of a prototype that could fly in two


years remains. Government agencies, moreover, seem to be sold on the


Helicostat idea and could participate in the finaftcing of its devel­

opment.


7 
Description of the New Helicostat


The formula that has been adopted is that of the "catamaran", two


1500 m3 keels connected by a transversal beam supporting the engines,


propellers, rotor, cockpit, and winch. To park, the craft lands on


small reinforced balloons located on the bottom portion of the keels.


These include an external envelope pressurized with air, internal


I


small balloons inflated Iwith helium, and a beam and stiffeners providing


rigidity and transferring forces.


This piston engines would be Lycoming IGSO 540 AID engines, each


furnishing, at continuous maximum power, 360 HP between 0 and 3200


meters of altitude and driving;


- two pusher-type variable pitch propellers, 3 meters in diameter,


providing also yaw control and playing an anticoupling role;


- one rotor, 11.68 meters in diameter. In fact, it is the rotor


used in the SA 365 "Dauphin" equipped with a "Starflex" hub assembly


The rotor driving &ssembly is also that of the SA 365.


The computed weight budget is the following:


- Empty weight, fully equipped: 2428 kg (567 kg for the keels,


639 kg for the structure, 975 kg for propulsion; 247 for the pilot


and equipment),


- Fuel, 407 kg, ORIGINAL PAGE 1 
- Weight when ready for use, 2835 kg. OF POOR QUALITY


The Empty weight being counterbalanced by the small balloons filled


with helium, the maximum payload (load plus fuel) is then equal to the


rotor lift force, or:


- with two engines: 3000 kg at ground level, 2400 kg at 2000 m.


with standard atmospheric conditions plus 20 (220C)


- with one engine: 2100 kg at ground level, 1600 kg at 2000 m,


and 221C.


Maximum speeds remain relatively high. with two engines, 90 km/h


empty, 86 km/h loaded; with one engine, 61 and 54 km/h, at 2000 m and


8 
220C; 104 km/h empty and 93 km/h loaded (76 and 68 km/h with one


engine). These speeds are in any case very adequate for the type of


applications planned.


Maximum Safety


The total mass can therefore reach about 5400 kg. However, the


weight does not exceed that of the payload. This explains the very
 

high safety factor that this formula brings; in case of failure of one


engine, the craft descends (slowly) only if the payload exceeds 2 tons.


In the very improbable case where both engines stop simultaneously,


the free-fall velocity with a full load is 15 meters/second. However,


if we assume that the sling is 30 meters in length, as soon as the


payload touches the ground, the weight becomes nil or very low (that


of the fuel) and the fall rate decreases rapidly; at 10 meters it is


only 7 meters/second and the Helicostat touches the ground at 4.4


meters/second. The keels inflated at low pressures then act as shock


absorbers. The "catamaran" formulahas been selected for obvious


reasons. twin-engine formula with a single rotor (no separate systems


on each side of a single balloon; safety further increased by having


the balloons protect the rotor; cockpit in a center location; elimi­

nation of the landing gear, and finally, lower manufacturing cost.


Let us mention further that, in the case of small payloads, it


would be possible to fly economically with a single engine. 
 
Operational Costs


Operational costs have been analyzed: cost per flying hour would


be less than 1500 FF for 1000 hours per year As for productivity,


it would be 50% greater than that of the helicopter, the lifting ca­

pacity more than compensating for the increase in round-trip time


(the helicopter is faster). For example, for respective times of 5


and 3 minutes, productivityis 19.2 tons/hour against 13.6 for the
 

"Lama". Then we have in this particular case (20 trips for the "Lama"


12 for the Helicostat) an average cost per ton of 100 to 120 French


9 

/22 
francs for the Helicostat and 175 to 190 French francs for the "Lama"


(125-225 for cable systems). It is not therefore surprising that lum­

ber companies and specialists in this field are interested in this


future machine.


The Aerostat


But Aerospatiale is not only interested in the Helicostat, al­

though this device is the fastest and least expensive to build and also
 

the one for which an immediate application can be analyzed with great


accuracy, thanks to experience acquired with the "Lama" used for lum­

ber operations by the company "Air-Forft".
 

The transportation of heavier loads (internal structural compo­

nents) is still under study, using the "Aerostat Formula", that is to


say, a device with a lift capacity that includes the load provided by


a single aerostatic force, one or more rotors being used only for pro­

pulsion and control. It is the formula used in the "Obelix" but applied


to much lower loads, 15 tons for example. For more than a year, dy­

namic mooring tests applied to such an Aerostat have taken place,


using a small Zodiac balloon of about 10 m 3, equipped with five fixed


pitch propellers driven with electric motors (see our magazine cover);


the whole assembly is controlled about all three axes (one propeller


provides thrust; two propellers control pitch, two others control yaw).
 

through automatic systems (attitude control systems) devised in coop­

eration with SFENA. Sensors are accelerometers for pitch and a magne­

tometer for yaw. Dynamic mooring, that is, the immobilizing of the


craft relative to the ground, is obtained with a system using photo­

electric cells.


The pilot controls the craft by remote control, using stabili­

zation control systems. This overall system gives good results and


on a real craft it would be possible, in order to position building


structural components, to obtain very accurate positioning relative


to the ground with relatively simple means.
 

10 rpO~ 
Aerospatiale (Aircraft and Helicopter Divisions) estimates that


development with Zodiac and SFENA of al30,000 mAerostat having an empty


weight of 11.5 tons and with a commercial payload reaching 17.5 tons


would require 4 years to reach the operational stage. Such a craft,


because of the need for ballasting after depositing its payload on the


ground, would have low turn-around frequency but would be justified


by the nature of the projected function.


The Port Shuttle


For shuttle-type operations applied, for example, to servicing


ports (loading and unloading ships) that are inadequately equipped,


Aerospatiale returns on the contrary to a formula that is closer to


the Helicostat in its "Port Shuttle" project which, for a comparable


3
envelope volume (30,000 m , 71 meters in length) would be capable of


lifting maritime containers 40 feet (12 meters) in length and to set


payloads in place accurately in spite of 20 knot winds with 5 meter/


second gusts from any direction. High engine power is thus necessary.


This has led to a 30-ton payload Helicostat project with four "Super­

Puma"-type rotors (with Starflex drive shaft), driven by eight 1800 HP


turbines (i.e., a total installed power of 14,400 HP). Such a machine


also 71 meters long, would have an empty weight of 20.5 tons, and a


take-off load of 54 tons with 3 tons of fuel and 30 tons of merchan­

dise. The four rotors could tilt slightly. Claimed autonomy: 3.5


hours; maximum speed: 125 km/h, distance that can be covered, greater


than 300 km.


Such a "Helicostat" would have applications that are important,


since the choking of certain seaports is not about to be resolved


rapidly.


11 
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Utilization of a Port Shuttle Capable of loading


30-ton containers.


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A new helicostat from SNIAS helicopter division

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