LV-T91 "Cheetah" Liquid Fuel Engine
 | Available only with the Making History Expansion installed. |
| LV-T91 "Cheetah" Liquid Fuel Engine | ||
 | ||
| Liquid fuel engine by Jebediah Kerman's Junkyard and Spacecraft Parts Co | ||
| Radial size | Medium, Radial mounted | |
| Cost | (total) | 850.00 
|
| Mass | (total) | 1.000 t |
| Drag | 0.3-0.2 | |
| Max. Temp. | 2000 K | |
| Impact Tolerance | 7 m/s | |
| Research |  Heavier Rocketry
| |
| Unlock cost | 3 400
| |
| Since version | 1.4.1 | |
| Part configuration | LiquidEngineLV-T91.cfg | |
| Maximum thrust | (1 atm) | 52.82 kN |
| (vacuum) | 125.00 kN | |
| Isp | (1 atm) | 150 s |
| (vacuum) | 355 s | |
| Fuel consumption | 7.18  /s
| |
| Thrust vectoring | 4 ° | |
| Electricity generated | 5.0 ⚡/s | |
| Testing Environments | ||
| On the surface | Yes | |
| In the ocean | Yes | |
| On the launchpad | Yes | |
| In the atmosphere | Yes | |
| Sub-orbital | Yes | |
| In an orbit | Yes | |
| On an escape | Yes | |
| Docked | No | |
| Test by staging | Yes | |
| Manually testable | Yes | |
| Packed volume | None | |
The LV-T91 "Cheetah" Liquid Fuel Engine is a liquid fuel engine with high efficiency in vacuum.
Usage
The Cheetah fits neatly between the Terrier and Poodle in terms of cost, mass, thrust, and thrust-to-weight ratio, and it has a slightly higher vacuum specific impulse than either.
(Its notably higher atmospheric Isp, while still too low to work well at Kerbin sea level, is an additional advantage in thin air e.g. Duna's.)
Overall, it performs well, though the range of delta-V, TWR, and payload mass for which it is the optimal engine may be narrow.
Product description
| “ | This engine will get you moving fast. Eventually.… Great for those long distance trips in space despite its namesake. Marketing, you know? — Jebediah Kerman's Junkyard and Spacecraft Parts Co |
” |
Variants
As of version 1.4.1 this engine has two models that can be switched in the editor. The Cap 1.875 variant is radial size medium, while the Bare variant is size small.
Trivia
Real-world comparison
The LV-T91 was inspired by the American LR91, used as an upper stage engine in the Titan rocket family.
Changes
- Increased unlock cost from 3000 to 3400
- Decreased cost from 1000 to 850
- Increased crash tolerance from 6 to 7
- Increased EC generation from 3 to 5
- Increased vectoring from 3 to 4
- Improved Isp
- Added ModuleTestSubject
- Initial Release
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