Difference between revisions of "J-33 "Wheesley" Turbofan Engine"

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== Changes ==
== Changes ==
[[File:Basicjetengine.png|thumb|Appearance before [[1.0.5]]]]
* Remodeled and retextured
* I<sub>sp</sub> halved, thrust reduced
* I<sub>sp</sub> halved, thrust reduced

Revision as of 13:40, 21 November 2015

J-33 "Wheesley" Turbofan Engine
Part image
Jet engine by
C7 Aerospace Division
Radial size Small
Cost (total) 1 400.00 Funds
Mass (total) 1.50 t
Drag 0.2
Max. Temp. 2000 K
Impact Tolerance 7 m/s
Research Tech tree aerodynamics.png Aerodynamics
Unlock cost 4 000 Funds
Since version 0.15
Part configuration jetEngineBasic
Jet engine
Maximum thrust 120 kN
Isp (max) 10500 s
Fuel consumption 0.23 Units of fuel/s
Intake air consumption 29.60 Air unit/s
Thrust vectoring × No
Testing Environments
On the surface ✓ Yes
In the ocean ✓ Yes
On the launchpad ✓ Yes
In the atmosphere ✓ Yes
Sub orbital × No
In an orbit × No
On an escape × No
Docked × No
Test by staging ✓ Yes
Manually testable ✓ Yes

The Basic Jet Engine is an air-breathing engine which uses liquid fuel and intake air.


This engine is the first air breathing engine to unlock in the tech tree. Technically it is also the most basic one, hence the name. As on all engines, thrust varies with height. Contrary to all rocket engines, air breathing engines' thrust diminishes with increasing height. Furthermore differing from most rocket engines, this has a real impact on usage, as the effect is far more distinct.

Its maximum stationary thrust is rated with 80 kN at sea level. At about 4000 m it generates just 47 kN, at about 11000 m it generates not more than 8 kN, ceasing to work at about 15600 m. Note that the behaviour between these points (given in the part stats)is somewhat non-linear, especially above 4000 m.

Thrust output also varies with speed, although far less then on the more advanced engines. Up to mach 0.6 it stays somewhat constant, slightly rising to a maximum of about 170% at mach 1.6 – 1.8, dropping to zero at mach 2.5.

The Isp stays constant over the full range of application, which is a big change to KSP pre 1.0 versions. It is rated at 9600 s, making it the nominal most fuel efficient engine. However, as the thrust/height curve of this engine limits its usage to still quite thick air, this value is somewhat put into perspective.

All in all, it works best at 8000 – 12000 m height. Flying lower, the high air resistance requires more thrust which lowers the fuel efficiency, while in higher areas the engines thrust output is just too low for reasonable flight.

Note that currently, the only planets which these engines will work on are Kerbin and Jool's moon Laythe.

Product description

A standard air breathing engine. This model utilizes limited range thrust vectoring. This engine works best at low cruising speeds and altitudes.

Created by: C. Jenkins


The designation “J-33 Wheesley” may be a reference to the real-life JT3D turbofan jet engine, also known as the TF33, made by U.S. aerospace company Pratt & Whitney which was involved with the Space Race.


Appearance before 1.0.5
  • Remodeled and retextured
  • Isp halved, thrust reduced
  • complete overhaul of most characteristics
  • Initial Release