Difference between revisions of "RE-I2 "Skiff" Liquid Fuel Engine"

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{{:RE-I2 "Skiff" Liquid Fuel Engine/Box}}
 
{{:RE-I2 "Skiff" Liquid Fuel Engine/Box}}
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The '''RE-I2 "Skiff" Liquid Fuel Engine''' is a relatively light and versatile [[Radial size | 2.5m or 1.875m]] sustainer-type [[liquid fuel engine]].
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== Usage ==
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The Skiff is average or above average in each metric of engine performance. It is inexpensive and lightweight, has thrust vectoring, and both its thrust-to-weight ratio and its [[specific impulse]] are above average, both in atmosphere and in vacuum.
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It does not excel in any single category; in some ways it is a "Jack of all trades, master of none." In rockets that solely use serial staging, for each of those stages, it is likely that another more specialized engine will outperform the Skiff. But when using parallel staging i.e. boosters, especially with [[Asparagus staging | fuel crossfeed]], the Skiff's versatility can give good performance at launch, after booster separation, and in orbit. This allows for reducing the number of engines, thus reducing the cost and dry mass of the rocket.
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The Skiff slots between the two most closely comparable engines, the [[LV-T45 "Swivel" Liquid Fuel Engine|Swivel]] and the [[RE-I5 "Skipper" Liquid Fuel Engine|Skipper]]. Relative to the Swivel, the Skiff gives 40% more thrust for less than 7% more weight, with better efficiency both in atmosphere and in vacuum. The Skipper gives more than double the thrust for 88% more mass, and improves on the Skiff's [[specific impulse]] in atmosphere, but comes with a correspondingly higher price and slightly lower efficiency in vacuum.
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As the lightest 2.5m engine, the Skiff can also be useful for transporting relatively light but wide payloads which would be awkward or impossible to fit in smaller fairing sizes.
  
 
== Product description ==
 
== Product description ==
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== Variants ==
 
== Variants ==
As of {{version|1.4.1}} this engine has two models that can be switched in the editor.
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As of {{version|1.4.1}} this engine has two models that can be switched in the editor. The Shrouded variant is [[radial size]] large, while the Bare variant is size medium.
  
 
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*Despite being claimed to have high vacuum efficiency, the records are actually false when you compare this with the Wolfhound, which is far more efficient, and [https://forum.kerbalspaceprogram.com/index.php?/topic/172401-the-wolfhound-and-the-skiffs-stats-seem-to-be-switched/| realize that the 2 engines’ stats are actually swapped, especially if you factor in their real-world counterparts for comparison].  Fortunately, this only affects realism and therefore the [[Wolfhound]] is higher up the [[Tech Tree]] than this engine.
 
*Despite being claimed to have high vacuum efficiency, the records are actually false when you compare this with the Wolfhound, which is far more efficient, and [https://forum.kerbalspaceprogram.com/index.php?/topic/172401-the-wolfhound-and-the-skiffs-stats-seem-to-be-switched/| realize that the 2 engines’ stats are actually swapped, especially if you factor in their real-world counterparts for comparison].  Fortunately, this only affects realism and therefore the [[Wolfhound]] is higher up the [[Tech Tree]] than this engine.
 
=== Real-world comparison ===
 
=== Real-world comparison ===
The RE-I2 was inspired by the American [[w:Rocketdyne J-2|J-2 engine]].
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The Skiff was inspired by the American [[w:Rocketdyne J-2|J-2 engine]].
  
 
== Changes ==
 
== Changes ==

Revision as of 06:46, 10 October 2023

RE-I2 "Skiff" Liquid Fuel Engine
Part image
Liquid fuel engine by
Rockomax Conglomerate

Radial size Large, Radial mounted
Cost (total) 2 300.00 Funds
Mass (total) 1.600 t
Drag 0.3-0.2
Max. Temp. 2000 K
Impact Tolerance 7 m/s
Research Heavier rocketry.png Heavier Rocketry
Unlock cost 9 200 Funds
Since version 1.4.1
Part configuration LiquidEngineRE-I2.cfg
Maximum thrust (1 atm) 240.91 kN
(vacuum) 300.00 kN
Isp (1 atm) 265 s
(vacuum) 330 s
Fuel consumption 18.54 Units of fuel/s
Thrust vectoring 2 °
Electricity generated 3.0 ⚡/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 RE-I2 "Skiff" Liquid Fuel Engine is a relatively light and versatile 2.5m or 1.875m sustainer-type liquid fuel engine.

Usage

The Skiff is average or above average in each metric of engine performance. It is inexpensive and lightweight, has thrust vectoring, and both its thrust-to-weight ratio and its specific impulse are above average, both in atmosphere and in vacuum.

It does not excel in any single category; in some ways it is a "Jack of all trades, master of none." In rockets that solely use serial staging, for each of those stages, it is likely that another more specialized engine will outperform the Skiff. But when using parallel staging i.e. boosters, especially with fuel crossfeed, the Skiff's versatility can give good performance at launch, after booster separation, and in orbit. This allows for reducing the number of engines, thus reducing the cost and dry mass of the rocket.

The Skiff slots between the two most closely comparable engines, the Swivel and the Skipper. Relative to the Swivel, the Skiff gives 40% more thrust for less than 7% more weight, with better efficiency both in atmosphere and in vacuum. The Skipper gives more than double the thrust for 88% more mass, and improves on the Skiff's specific impulse in atmosphere, but comes with a correspondingly higher price and slightly lower efficiency in vacuum.

As the lightest 2.5m engine, the Skiff can also be useful for transporting relatively light but wide payloads which would be awkward or impossible to fit in smaller fairing sizes.

Product description

The Skiff is well suited for local planet hopping. High vacuum efficiency for this powerful upper stage drive will get you further.

Rockomax Conglomerate

Variants

As of version 1.4.1 this engine has two models that can be switched in the editor. The Shrouded variant is radial size large, while the Bare variant is size medium.

Shrouded variant
Bare variant
The different variants of the engine

Trivia

Real-world comparison

The Skiff was inspired by the American J-2 engine.

Changes

1.6
  • Increased unlock cost from 4500 to 9200
  • Increased cost from 1500 to 2300
  • Increased mass from 1 to 1.6
  • Increased crash tolerance from 6 to 7
1.4.5
  • Added ModuleTestSubject
1.4.1
  • Initial Release