Quasiturbine> QT50AC> Basic Drawings


Since this website is widely dedicated to education,
and because early projects are precious part of the innovation history,
the QT50AC first project is more than a curiosity...

Q50AC Basic Drawings


While most rotary engines use the principle of volume variation between a curve and a moving cord, this new engine concept makes use of a "seven degrees of freedom  X, Y, q, ø1, ø2, ø3, ø4" rotor, trapped inside an internal housing contour, and does not require a central shaft or support. This concept is the result of research for an hybrid turbine-piston engine with a fixed center of gravity during rotation (zero vibration). The invention is an assembly of four carriages supporting the pivots of a four-element, variable-shape rotor. This rotor rolls on the inner surface of a profiled stator shaped like a skating rink (just like a roller bearing). During the rotation, the rotor components align alternatively in a lozenge and a square configuration. This device can act as a pump, a compressor, a flow meter, or as an engine (including pressurized fluid mechanical energy converter). It is self-synchronized and uses no valves (only fixed ports in the stator or alternatively, ports on the lateral side covers). Central support of the rotor is not required for most applications. Four cycles are completed in every rotation. The maximum geometrical compression ratio is a function of the maximum diagonal ratio selected at design. As for turbine engines, ignition is only required initially, since combustion is kept continuous between successive cycles by way of an ignition transfer slot or cavity. The continuous combustion produces an enhanced dynamic compression ratio. The device incorporates few parts. It has an excellent torque continuity even at low rpm (Due to its high torque pulsation rate, this device requires less flywheel effect and gearbox ratio for most applications). It is suitable for uses such as aeronautics, where high reliability is required. Having no oil pan, it can be operated in completely submerged or hostile environments. The asymmetry of the strokes and the precocity of the mixture intake and gas expansion (without excess volume during expansion) allow for a better initial mechanical energy conversion. A fast reduction in the combustion chamber of the temperature, the pressure and the confinement time leads to less NOx production, and less heat transfer toward the engine block, all contributing to improve the power density and the efficiency over the piston engine. The Quasiturbine meets the hydrogen engine criteria.

Drawings and photos

QtDuvalPlexi99.jpg (14260 bytes)

 QtDuvalPoulie99.jpg (11326 bytes)

Quasiturbine Engine - Stator profile, with groove
and quasi circular pressure ring positioning.

QT50 Data


Major axis = 5.570". Minor axis = 4.700"

Each chamber volume = 1.49 po2 x thickness (po)

Displacement volume per rotation = 4 x 1.49 x thickness (po) , po3/rotation; or 4 x 9.6 x thickness (cm) , cm3/rotation

Assuming a thickness of 2.000"

Aspirated volume per rotation = 11.9 po3 /rotation; or 200 cm3 /rotation

(The power generated must be compared to a 2 stroke engine)

"Saint-Hilaire" contour

Comment on the "Saint-Hilaire" contour profile calculation

Quasiturbine Engine - Components template
(Lozenge, carriage & mechanical coupling)

Blow up diagram of the prototype

Click on the illustration for a higher resolution

Quasiturbine Engine: Blow up of stator, rotor assembly,
carriages, port positioning and mechanical coupling.
(Square arrangement on the left, lozenge on the right)

10 - L'ensemble moteur
11 - Boitier incluant 2 parois
12 - Contour SAINT-HILAIRE
13 - Pale pivotante
14 - Bourure
15 - Prise de traction
16 - Pivots
17 - Chariot
18 - Rouleau
19 - Centres de rouleau
20 - Trajectoire centre de Pivots
21 - Paroi avant
22 - Paroi arrière
23 - Ouverture dans paroi arrière
24 - Joint tiroir
25 - Join papillon
26 - Joint divisé avancé
27 - Ressort plat
28 - Joint linéaire
29 - Joint arc
30 - Joint circulaire
31 - Joint chariot
32 - Arbre
33 - Bras de couplage
34 - Tringles de poussée
35 - Bougie
36 - Canal d'allumage
37 - Fenêtre de bougie
38 - Fenêtre de bougie paroi
39 - Fenêtre
40 - Bouchon
41 - Fénêtre carburateur
42 - Fenêtre carburateur paroi
43 - Fenêtre échappement
44 - Fenêtre échappement paroi

More Photos

(click on the photo to enlarge full page or view more photos)

QTLiqAssembParoi.jpg (19146 bytes)

Plexiglas prototype: Rotor assembled, with the stator and lateral covers.

Plexiglas prototype all assembled in the stator, with the lateral covers.

Perforation template applied to Plexiglas prototype.

Drawing template for stator profile, with lateral covers.

Some anterior prototypes !

The first metal prototype built in February 1997

More Technical...

QT50AC Characteristics