Steam turbine powered turboprops and turbojets 1931-1972

Steam condenser air exhaust creates approximately 2,000 lbs of additional per engine at takeoff.
At 30,000 ft and 400mph air temperature after condenser is 261F and jet nozzle pressure ratio is 1.5. Aircraft speed is 587 ftps, jet exhaust velocity is 932 ftps. Air flow 370lbs/s per engine. Each steam turbine produces 6,213HP. Net propulsion efficiency based on boiler efficiency 90% is 11.8% which is equivalent of 15% efficiency gasoline engine with propeller. Jet fuel flow is 16,000 lbs per hour, coal/oil mix(65%/35%) flow is 19,200 lbs per hour. These are very high numbers and comparable to an equivalent zero bypass turbojet aircraft fuel consumption at the same speed.
Weight of the complete powerplant based on 1938s Nathan Price's 5000hp turbocharged steam generator(1,800 lbs) and calculations from the technical papers mentioned above is 2x(1,800+6,000)=15,600 lbs or 12.6% of the takeoff weight 56,000 kg(123,457 lbs).
Considering that the steam power plant is 5,000 lbs heavier, the available fuel weight is about 33,000 lbs. It means that this aircraft can fly up to two hours on jet fuel or 1.5 hour on coal/oil mix.

A better steam powerplant efficiency can be obtained if atmosphere conditions are standard.
In this case net efficiency is 15.5%, and flight time is 2.5/2 hours. Also efficiency greatly improves at 36,000 ft altitude and high subsonic speeds of at least 500 mph.

Air fan diameter is both cases is about 50 inches and rotates at 6,000 rpm, and the steam condenser-radiator is slanted inside the nacelle at 30 degrees angle to double its square footage.
Jet nozzle has a moving cone that allows regulation of compression ratio from minimum at takeoff to maximum at cruising altitude.
Propeller has diameter 5.3 m and is only used during takeoff, loitering, approach to air field and breaking during landing.

In 1920s-1950s there were several projects of aircraft powerplants with mercury vapor Rankine cycle. Because mercury is condensing in this cycle at very high temperature of at least 600F the air radiator for the aircraft can be downsized by at least 3 times. Working pressure of this system is also 5-10 times lower than for the water steam powerplant. High exhaust temperature of cooling air is beneficial for the Meredith effect propulsion.


https://patentimages.storage.googleapis.com/40/f8/b7/6c971606f7f318/US1804694.pdf
Mercury vapor powerplant for the aircraft

Calculated Condenser Performance for a Mercury-Turbine Power Plant for Aircraft
Calculation of closed cycle mercury vapor turbopropeller powerplant for a 500 mph at 30,000 ft aircraft. 5000hp turbine requires radiator of about 25 square feet - 4 to 5 times smaller than for the water steam turbine power plant with the same net propulsive power.



https://digital.library.unt.edu/ark:/67531/metadc52866/m2/1/high_res_d/19630002662.pdf
Calculation of 1000 mph at 45,000 ft mercury vapor turbine compressor-jet aircraft.

Obvious disadvantages of this material are negative impacts on health, environment and also high cost.

Out of interest as they are outside of the timeframe specified, Clement Ader's steam engine...

Europe 206

Which he constructed to power his Avion III.

Europe 204

Both survive at the Musee des Arts et Metiers in Paris.

Liquid metals(molten sodium, potassium and mercury) and high boiling temperature organic liquids were also studied for closed Rankine cycle aerial vehicles propulsion.

https://archive.org/download/DTIC_AD0864962/DTIC_AD0864962.pdf

A study of various advanced powerplants for
a large helicopter:
Closed Brayton cycle gas turbine (heavy oil fuel, coal, boron, metals)
Potassium metal closed Rankine cycle (heavy oil fuel, coal, boron, metals)
Mercury closed Rankine cycle (heavy oil fuel, coal, boron, metals)
Organic Rankine cycle (heavy oil fuel, coal, boron, metals)
Recuperated intercooled turboshaft turbine
Fuel cell electric drive (hydrogen, jet fuel)
Magnetohydrodynamic electric drive (jet fuel, heavy oil, hydrogen)
Thermionic electric drive (heavy oil, solid fuel)
Fission energy powered cycle turbines (Rankine and Brayton.
Calculations were made for 500, 1500 and 10000 hp powerplants. Each helicopter has 2 such powerplants.
Potassium metal Rankine helicopter 2x10000hp powerplant with all fuel aboard(25,000 lbs) is about 85,000 lbs with 1969s technology and 45,000 lbs (fuel-20,000 lbs) with 2020 technology. Efficiency is around 30%.
Mercury poweplant is 5 times heavier , occupies 9 times larger volume and has only 15% efficiency.
Cost is high due to use of molybdenum and tantalum alloys. Turbine seals leak is very serious problem for this power plant, especially for molten potassium.
Organic Rankine cycle has about the same weight and efficiency as potassium powerplant, but requires 3.5 times larger volume.
Water steam powerplant was not studied but is probably can have parameters close to mercury powerplant or worse.

Steam turbine aircraft turbochargers and auxiliary drives:

US2233031
Aircraft powerplant supercharger with the steam turbine and steam condenser radiator
https://patentimages.storage.googleapis.com/ca/83/20/557106562193d7/US2233031.pdf

US2159758A United States

Power plant - steam assisted aircraft powerplant


https://patentimages.storage.googleapis.com/cd/67/3b/ee212a77b18119/US2159758.pdf



US6786036B2 United States


Bimodal fan, heat exchanger and bypass air supercharging for piston or rotary driven turbine

https://patentimages.storage.googleapis.com/ec/3d/c8/e510e64a6eae8c/US6786036B2.pdf

Abstract
The present invention relates to turbine fan aircraft use. In particular, the present invention is directed toward a turbine fan driven by a piston or rotary (e.g., Wankel) engine. The present invention makes possible the most flexible and effective installation of a ducted fan with a fixed horsepower source, namely a conventional internal combustion engine. Effectiveness being defined as full utilization of the engine's available horsepower at the chosen flight points. In a further embodiment of the present invention, a novel heat exchanger may be provided which removes waste heat with minimal drag while boosting the fan system's effective thermal efficiency by increasing the enthalpy of the working fluid. In yet another embodiment of the present invention, bypass air from the turbine may be used to supercharge the piston or rotary engine.

Steam turbine assisted aircraft turbojet engines patents:

GB2334556A
Turbojet with steam turbine

https://patentimages.storage.googleapis.com/a5/f7/61/f444a9f2272cce/GB2334556A.pdf


Abstract

The Thermo Induction Turbojet operates by drawing in air and compressing it in an axial flow compressor 1. Front here it is passed into combustion chamber 6 where it is mixed with fuel from nozzles 5 and burnt. The rapidly expanding hot gases pass around convoluted water tube 10 and over encased steam turbine 3, exiting through jet nozzle 12. Water supplied from pump 8 is force circulated through water tube 10. This cools the combustion chamber and produces high pressure steam. The steam is fed via nozzles 11 to steam turbine 3, thus rapidly rotating it, the connecting shaft 2 and compressor 1. Exhausted steam exits the turbine via ducts 13 and manifold 14. From here it travels via pipe 15 to a suitable condenser in the front of the engine. Condensed water is recirculated via pump 8.


Working model of this engine was built by inventor.



US4333309A
Steam assisted gas turbine engine

https://patentimages.storage.googleapis.com/75/94/b8/7eafe1aaaebc48/US4333309.pdf

Abstract
A gas turbine engine is disclosed which has an integral steam power system consisting of heat absorbing boilers which convert an unpressurized liquid into an expanded and heated steam by utilizing heat normally lost through component cooling systems and the exhaust system. Upon completion of the steam power cycle, the steam is condensed back to a liquid state through a condensing system located within the compressor and other functional components of the gas turbine engine. A system of high pressure air and friction seals restrict steam or liquid condensate within designed flow bounds. The gas turbine engine disclosed is designed to give improved fuel efficiency and economy for aircraft and land use applications.

nuuumannn said:

Out of interest as they are outside of the timeframe specified, Clement Ader's steam engine...

View attachment 572432Europe 206

Which he constructed to power his Avion III.

View attachment 572433Europe 204

Both survive at the Musee des Arts et Metiers in Paris.

Click to expand...

That is an absolutely gorgeous machine.

Steam turbine propeller driven aircraft, airboat and train were patented in 1920s-1930s by German inventor Rudolf Wagner.
Steam turbine propeller drive had power 1000-3000 hp depending on steam parameters.
Most interest interesting applications of this powerplant were high speed airboat and passenger train that were able to use cheap coal fuel.