A Pulse Ejector Thrust Augmentor or PETA is a proprietary
pulse jet engine
300px, Diagram of a pulsejet
A pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need ...
developed by
Boeing
The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and ...
.
The Boeing PETA design embeds the pulse jet inside a thrust augmenting duct which
entrains surrounding air into the exhaust stream. This entrained air improves
thrust
Thrust is a reaction force
In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can al ...
and cools the pulse jet. Boeing may use the PETA in its Light Aerial Multi-purpose Vehicle (LAMV) Future Combat System.
Advantages
*The pulse jet engine's ability to be almost instantly throttled, with spoolup/spooldown time from minimum to max thrust and vice versa of around of 1–1,5 seconds, and startup and shutdown times of less than five seconds, would be advantageous in a
vertical take-off and landing (VTOL)
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
, where quick response to control input is useful.
*The ability to provide upward thrust and thus decouple vertical and axial movement of the aircraft.
*Valveless pulse jet engines are insensitive to sand and small debris.
*The engine's thrust augmenters can be incorporated as load bearing structures in the aircraft's
superstructure
A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships.
Aboard ships and large boats
On water craft, the superstruct ...
, thus reducing overall weight.
*The design features no moving parts, which the creators claim increases reliability compared to conventional engines with
moving parts.
*Multiple engines can be assembled into an
array, allowing scalability to heavy-lifting applications.
*Arranging the engines in an array allows for distributed, highly
redundant thrust, thus increasing reliability.
Disadvantages
*Pulse jet engines are notorious for being loud. Owners of large engines (1800N thrust and above) have reported receiving noise complaints from people who were shielded from the "test site" by 7 km of hilly terrain covered by a dense forest.
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References
External links
Wired.comGoogle Patents US6883304
Pulsejet engines
Aircraft engines
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