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[1.0.5] The RAT Pack - Ram Air Turbines, Thrust Reversers, Terrain Warning System (0.30)


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Latest Version: 0.30

After noticing a sharp rise in crashes Gene Kerman commissioned a study on why rockets and planes crash. The resulting 3,151 page report was turned over to SatNet Aerospace to research and develop parts that could reduce crashes or make them more survivable. The first parts to come out of the project were Ram Air Turbines and the group was quickly dubbed “The RAT Pack". Even as they expanded into more flight safety parts the name stuck.

 

The RAT Pack:

Ram Air Turbines

The RAT Pack provides Ram Air Turbines that generate power from flowing air. I was partly inspired by a documentary on the "Gimli Glider", a 767 that had to glide to a landing with nothing but batteries and a RAT to power critical systems. A couple of spaceplane landings where I had to constantly manage electric charge to maintain control and keep enough for the landing gave me some incentive to actually build it. The RATs are designed to provide emergency power and have peak power at or slightly above that of an RTG. Electric charge output is a function of both airspeed and atmospheric density.

 

  • RAT-1 "Pinwheel" Ram Air Turbine - As basic as they come, it provides little power and must be activated manually.
  • RAT-360 "Cage Master" Ram Air Turbine - Generates more power and will automatically start up when electric charge is depleted.
  • RAT-720 "Topper" Ram Air Turbine - A RAT built into a nosecone. It has a higher peak power than the RAT-360, but has a performance curve similar to the RAT-1.
  • RAT-6000 "Pack Master" Ram Air Turbine - The most powerful RAT. This one has the ability to control electric charge flowing from its internal battery and turns it on only when it is activating. It is able to generate peak power over a broader range.
  • EPM-MK3 “Emu" Emergency Power Unit -  A complete emergency power solution with a RAT, Fuel Cell, and APU.

Thrust Reversers

Thrust Reversers redirect the engine thrust. They are used to reduce stopping distance once landed. I developed it primarily for Duna spaceplanes where a short stopping distance is a huge asset. They will redirect the thrust of the engine attached to them. Attaching multiple engines will not give you the desired behavior as only one engine will be reversed.

  • TR-1 “Backup" Thrust Reverser - Designed to fit a Turbojet or RAPIER engine.
  • TR-L “Way Back" Thrust Reverser - Designed to fit longer 1.25 m engines, particularly the LV-N.

Terrain Awareness and Warning Systems

A Terrain Awareness and Warning Systems (TAWS) gives you a chance to avoid a crash by warning you while you still have some time to react. It uses the radar altimeter and some calculations to figure out what the terrain looks like. It also has an obstacle detecting radar (FLT Radar), however it only activates below a certain altitude and uses a fair amount of power when in use.

  • TAWS-1 "Lookout" Warning System - Equipped with Ground Proximity Warning System (GPWS) and Forward Looking Terrain (FLT) Radar.
  • TRS-1 "Lookdown" Terrain Radar - Terrain scanning to improve landings.

Launch Escape System Trigger

I came across this post http://forum.kerbalspaceprogram.com/index.php?/topic/122361-launch-escape-system-rocket-stack-failure-detection/ and thought it was in line with this mode and a great idea.

  • LEST-1 "Oops" LES Trigger - Detects a unplanned disassembly and hits the abort button for you.

Download:

Kerbal Stuff

Source:

GitHub

License:

LICENSE.md

Development Thread

Questions and Answers:

Spoiler

 

Q: Are these RATs realistic?

A: Somewhat. The power curves where inspired by real RATs, but have been heavily Kerbalized.

Q: Where can I use RATs?

A: Anywhere with an atmosphere. Kerbin, Duna, Eve, Laythe are all good places to use them. Jool and Kerbol might work, but you'll probably be crushed or melted before you get any power.

Q: What happens if I run out of power landing on the Mun with a RAT?

A: You will probably hit the Mun and the RAT will be destroyed.

Q: What happens if I run out of power landing at the KSC with a RAT?

A: If you have an auto-activating RAT it will deploy and start generating power. If it is a manual RAT, you can't activate it after losing power, so prepare for high speed lithobraking.

Q: Do RATs work inside fairings or cargo bays?

A: No, they need to be in the air-stream.

Q: How does orientation affect RATs?

A: Right now it doesn't, though that may change in the future.

Q: Can I fly backwards using a thrust reverser?

A: Yes, though it is not recommended. Most planes and rockets are not aerodynamically stable in both directions.

Q: How much thrust will a thrust reverser reverse?

A: Short answer - you lose a lot of thrust, but it should be enough to stop quickly. Long Answer - Each TR has a thrust modifier which defaults to 50% intended to account for thrust lost to exhaust escaping to the sides. Additionally the thrust direction is not directed in reverse, but in a 45 degree angle above and below the engine. The net thrust is in reverse, but there are significant losses from the thrust directed up and down that cancels out.

Q: Will a thrust reverser work in space?

A: It will, though you are effectively reducing your engine efficiency, so you are better off re-orienting.

Q: Why doesn't my descent rate match my vertical speed?

A: They are similar but different values. Descent rate is probably better described as ground closure rate. It is how quickly you are approaching the ground. Vertical speed is how quickly you are changing altitude relative to a common reference radius (i.e. sea-level). If you are on level terrain they will be the same. If however the ground is rising relative to sea-level you will have a higher ground closure rate than vertical speed which is a really important distinction when deciding whether you will hit the ground at some point in the near future.

Q: Will I always have time to pull up when TAWS issues a warning?

A: Not necessarily. The current values are very... "Kerbal", they give you a chance at survival, but no guarantees. If you aren't trying to hit terrain it is usually enough warning to avoid the occasional near miss, but if you deliberately try to test the limits you will hit the ground at least some of the time. You can set your own values, but I found anything that would ensure survival was too conservative for the way I fly in game.

 

 

 

 

 

NOTE: I'm referencing the stock textures. If you modify or remove textures from the stock parts these parts will fall back to the solid black placeholder texture.

Edited by satnet
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Nice! Those are some beautiful parts with wonderful functionality! thanks:D

Edit: are they integrated into the techtree yet?

Thanks for the compliment. Getting the models/animations to this point was a fun learning experience and I'm glad someone else thinks they turned out well.

Yes, they are in the tech tree. The RATs are spread through out because there is some variety. The RAT-1 shows up very early as a power option while most people are still on sub-orbital flights (it seemed well suited to that) and the rest show up the aerodynamic branch. TAWS show up in landing and Thrust reversers show up in high altitude flight.

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Okay, played around a bit with the first tiny RAT lovely stuff.

Am I right in noticing that there is a electricity generation even while standing still? Shouldn't it be dependent on speed and 'air intake'?:)

Again: complements on the models, great stuff.

As an improvement I'd love to see them rotate faster on higher speeds, but they're lovely as is.

Edit: Nevermind that question; flew some more and it does work as intended: the Pinwheel RAt didn't generate charge while standing still and maxed out at 0.7500 at about 200 m/s at 5 km height. Awesome stuff!

672C5A55A04C665BDAEF85DC048568662A454FDE

Edited by Artfact
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The rotation rate actually does depend on speed, but now that you mention it I need to adjust it because the effect isn't pronounced enough. In particular if it is activated and there is any speed at all (i.e. a slight sway in the rocket/plane) it runs fast enough to look like it is doing something useful even though the power output is a rounding error. I'll add this to improvements list for the next release.

Power output depends on speed and pressure similar to air intakes, though expect a realism pass in the next release. Recent discussions on the dev thread have been on the power curve and making them more realistic and varied. Expect orientation to matter and a more gradual power increase with airspeed.

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  • 3 weeks later...
Posted 0.20.

New Parts:
EPM-Mk3 - Emergency power unit for Mk3 aircraft. Contains a RAT, Fuel Cell, and APU.

Changes:
Reworked RAT calculation. Now takes into account orientation and occlusion. Reworked the atmospheric pressure handling.
Completely new power curves thanks to some great input from Reiver on the Dev thread. More varied and realistic.
A graphing function to show off the new power curves and make it easier to compare one RAT to another.
Fixed the animation rate when generating power.
Other small tweaks.
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  • 2 weeks later...

Version 0.30

New Parts:

TRS-1 - Terrain Radar which scans the ground below your ship and gives you a color coded view of the terrain.

LEST-1 - Launch Escape System Trigger that will auto abort if a part is unexpectedly destroyed.

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  • 1 month later...

I have found a use for thrust reversers in space: Most of my ships have docking ports opposite their engines. My nuclear space tugs have limited monoprop resources, but plenty of LF. Therefore, if I install a thrust reverser, they can use their LV-Ns for docking maneuvers. Congrats on a nice pack!

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  • 4 weeks later...

Just came across this after seeing a youtube video of it. The only download I see for it is the old Kerbalstuff link which no longer works. Is there plans for putting this on SpaceDock or any other location for download?

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2 hours ago, JeffreyCor said:

Just came across this after seeing a youtube video of it. The only download I see for it is the old Kerbalstuff link which no longer works. Is there plans for putting this on SpaceDock or any other location for download?

 

26 minutes ago, drtedastro said:

Oh i hope so.

I have been looking for something like this.

Please put it on spacedock or such.

Cheers.

The magic of github... https://github.com/KSatNet/RATPack/releases. Just needed to click through a bit! ;)

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