Advanced Jet Engine
is a mod that provides realism for turbojet, turbofans, air-breathing rockets, propellers and rotors in KSP. If you're concerned with how real airplanes perform or you're a flight simulator fan, this mod is for you. The level of engine simulation rivals most commercial flight simulators..
[Spoiler: So what's not realistic in KSP?]
[Spoiler: The mathematics behind AJE]
KSP is a game that focuses on rocket and rocket engines, all other types of engine are modeled in a similar manner to rockets. As a result, two fundamental flaws exists. Given that FAR is used instead of the stock aerodynamics, these flaws render all jet engines unrealistically overpowered.
1.In reality, the thrust of a jet engine is proportional to the gas flow through the engine core. Thus at high altitude where air is thinner, the engine should have less power. However in KSP as long as you spam enough "intakes", the engines have the same power as at sea level. As a result, almost any airplane should be able to reach a high mach number when it climbs high and face less drag. Similar problems stand for propellers and rotors.
2.The intakeAir is counted as fuel. For the stock part 'turbofan engine', one unit of Liquid Fuel is burnt with 15 units of IntakeAir. So the actual engine efficiency would be 15 times more than what Isp tells. In other words, the actual Isp would be ~30,000s, a ridiculously high value.
For explanation of jet engine parameters and algorithm, go to https://github.com/camlost2/AJEsolverTester
The propeller code is based on JSBSim
, with customization from NathanKell
Rotors use a simplified model by the author.
- Real-world jet engines AJE uses thermodynamic equations to calculate jet engine performance in flight.
- Real throttle Throttle is linked to fuel consumption instead of thrust. Afterburners, if installed on the engine, is turned on when throttle > 66% and off when throttle <= 66%
- Overheat.Like in real world, not all engines can tolerate the heat from air compression of hypersonic flight. The effect is affected by speed not throttle.
- Inlet.Each engine requires a minimum inlet area (see right click menu in editor). Make sure you have enough inlet till you see "Inlet Area:100%" in flight. Each inlet has a TPR(total recovery pressure) that is dependent on Mach number and angle of attack. Avoid TPR loss by facing the inlet to the freestream.
- RealFuels support.Engines use Kerosene if RealFuels is installed. RAPIER burns LqdMethane+LO2, SABRE burnes LH2+LO2.
- Mod friendly.Relatively easy to make configure for new engines and supporting many mods including B9,Firespitter,KAX,Taverius' Pizza,D12aerotech,SXT,RetroFuture,BahaMotoD'pack
AJE incorporates portions of NASA EngineSim; used according to NASA's license thereof with due credit. AJE incorporates portions of JSBSim by Jon S. Berndt, used in accordance with the LGPLv2
License is LGPL v2, with the following exception, that the authors reserve the right to veto the inclusion of this in any "mod packs" at their sole discretion.
Avoid quick overheating when DRE is installed
Minor change in ram drag calculation
Avoid the issue where piston engines cannot start at 0 throttle
Recompiled for FAR 0.14.6
Remove minimum throttle
Avoid engine flaming out on the runway
Part title cleanup
Fix a bug in inlet area calculation
redo jet engine code
Improvements over the original program include:
0.Everthing in SI units
1.Simple off-design calculation of compressors
3.All engine is one type
4.An option to mix fan duct and core flow before the nozzle
Recompiled for FAR 0.14.4
Some engines from RetroFuture mod
Determine spool up time based on engine size
Heat code rewrite by NathanKell
RAPIER uses LqdMethane
SABRE M thrust fix
Added a stock ramjet
RetroFuture engine & inlets (partial)
cfg cleanup & Misc. bug fix
Fixed compatibility without RF
Use JSBProp by NathanKell for propellers.
Changed definition of B9 tubofans
SABRE and RAPIER work better without RF
Ignore heatProduction if DRE is installed
tweaked the inlet code suggested by virandi
more engines and bug fixes
Backports from NathanKell's fork:
*Redone piston engine support (inter/aftercoolers, multiple speed/stage superchargers,
volumetric efficiency, ram air, and real performance for the included piston engines)
*Jets show gross thrust as well as net thrust
*Some intake area tweaks (still needs work to get sqft area of each intake part
*Ported over all real jets and piston engines from RftS.
*All included jets should perform like their real counterparts now. Real stats were used
when available, educated guesses made when not.
*Cleaning and variable-renaming in the EngineSim code for clarity and understanding
*Update to 0.24.2 and FAR 0.14.1.1
*Seamlessly works with or without RealFuels
Fixes from taniwha to the DA (TVPP) engines and intakes.
. .Fixed some inlet data
. .In-editor information of inlets and engines
. .Added some engines and inlets
. .Incorporated RftS textures for some B9 engines
. .A few more engines
. .Added support for RAPIER, tweaked SABRE
. .many DLL and CFG tweaks
. .Engines have 3% idle thrust by default
. .Added TV_pizza support and several engines
. .The propellers should work correctly on other planets(untested)
. .Added a new engine F404
. .Solved compatibility issue with latest HotRocket
. .Balanced propellers, added a speed buff
. .Support for KAX rotor wing
. .Added *realistic* support for propellers and rotary wings
. .Supporting all FS and KAX propellers, including electric ones
. .Stock "turbojet" becomes J58 with "bleed air" feature, thanks to NathenKell, who provided a simple and elegant solution.
. .Combined everything into one module: AJEModule supports ME and MEFX at the same time
. .Using stock atmosphere pressure and temperature now, engines should have ~10% more thrust at high altitude
. .Engines have 10% more heat tolerance to compensate
. .AJE works without HotRockets now
. .Fixed a bug with SABRE M
. .New afterburner logic
. .Upgraded J79 to J93, which is more powerful, especially for supersonic flight
. .Added CoM Offset to stock, B9 and FS engines, making RL rip-off designing more easy.
. .Air intakes has no physical effect now. Jet engines don't require intakeair, but they still need an atmosphere with oxygen to work.
. .Compatibility support
- My plane consumes fuel ridiculously fast. Fast yet realisticly rather than ridiculously. An F-16 that uses 1 x Pratt & Whitney F-100 has 3000 kg internal fuel, yet only lasts for minutes with full afterburner on. To see your airplane fly longer, either carry more fuel, restrain from using afterburner, or climb higher to save fuel.