The Marquardt Company was set up in 1944 for the purpose of study work into subsonic ram-jet engines. The company has since developed 50.8-centimetre diameter ram-jets capable of supplying power equivalent to 2500hp. A Lockheed F-80 "Shooting Star" fixed-wing aircraft was fitted with this ram-jet and during trial flights was powered solely by it, the normal power source having been switched off.

Development work has also been done on other ram-jet engines as well as on pulse-jet engines to equip target drones.

Marquardt has also produced a helicopter powered by two pulse-jet engines 20.4 centimetres in diameter. This helicopter, a simplified structure in steel tubing, was intended to act as a flying test bed for the pulse-jet engines developed by the Marquardt Company. At each tip of the two-bladed rotor were located the above-mentioned pulse-jet engines. Directional control was ensured by means of a rudder. The M-14 was the first American helicopter to have flown on power provided by two pulse-jet engines.

P.Lambermont "Helicopters and Autogyros of the World", 1958

Technical data for Marquardt M-14 Engine: 2 x pulse-jets, empty weight: 363kg, gross weight: 544kg, cruising speed: 104km/h

Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo for mysql5.zone.ee failed: Name or service not known in /data03/virt15346/domeenid/www.aviastar.org/htdocs/helicopters_eng/marquardt.php on line 69

Fatal error: Uncaught mysqli_sql_exception: php_network_getaddresses: getaddrinfo for mysql5.zone.ee failed: Name or service not known in /data03/virt15346/domeenid/www.aviastar.org/htdocs/helicopters_eng/marquardt.php:69 Stack trace: #0 /data03/virt15346/domeenid/www.aviastar.org/htdocs/helicopters_eng/marquardt.php(69): mysqli_connect('mysql5.zone.ee', 'd14657sa18989', Object(SensitiveParameterValue)) #1 {main} thrown in /data03/virt15346/domeenid/www.aviastar.org/htdocs/helicopters_eng/marquardt.php on line 69