Engine Failure on Takeoff (V1 Cut) (1.0.4)

[RexKramer]

The Challenge: Build and launch an aircraft with exactly two (2) jet engines. At liftoff, you are going to shut down one of the engines. The challenge is to see how well you are able to control the aircraft.

Rules:

1. Must have exactly 2 jet engines. J-33 Wheelsy, J-X4 Whiplash, and CR-7 RAPIER (in air-breathing mode only) are your available choices. Rockets and ion thrusters are not allowed. Vernor engines are not allowed. RCS is allowed, as long as it is not intentionally used to produce forward thrust, only to maintain directional control. Updated- Both engines must be the same model.

2. Engines must be mounted laterally, or one on each side of the aircraft. In other words, not mounted with one above the other one. The asymmetric thrust must produce a yaw moment, not a pitch moment.

3. The horizontal distance between the engines is up to you. Mounting two engines right next to each other on a bi-coupler at the back of the plane is perfectly fine. Mounting them on pylons on the side of the fuselage or under wings is fine. Clipping so that the engines overlap is not allowed. Updated- Engines must be mounted symmetrically, same lateral distance from centerline, and same fore/aft location.

4. One engine must be shut down at liftoff, and may not be used again for the duration of the flight.

5. You must set full (100%) throttle during the takeoff, and the remaining engine MUST remain at FULL THROTTLE until your reach an altitude of 1,000m. After reaching 1,000m you may use any throttle setting you wish.

6. The aircraft must take off horizontally from the KSC runway. It must also be capable of landing horizontally on the runway, although a successful landing is not required.

How to accomplish the engine failure: I recommend using action groups to shut off one engine. However, you may use other methods to accomplish this as well, such as right-clicking the engine and shutting down from the info-pane. It is acceptable to close the intake with the same action group button, but not required.

When to fail the engine: Engine should be failed after the nose begins to rise, but before reaching an altitude of 100m. Ideally the failure should occur before the main wheels leave the ground, but as long as you fail the engine before reaching 100m you’re good. Remember, you need to leave the good engine at max thrust until reaching 1,000m.

Mods: Stock parts only. The use of information mods such as MechJeb or Engineer is allowed. The use of any mods which alter stock parts, or add non-stock parts, or alter stock physics, is not allowed. With that said, if you would like to post your attempt using non-stock parts, feel free to do so, with a note that your aircraft uses non-stock parts. Entries using non-stock parts or physics will not be eligible for records.

Basic Challenge Completion: The basic challenge is to shut down one engine as described above, achieve an altitude of 1,000m, and land safely anywhere, preferably on a runway (but any landing you can walk away from is a good one, right?).

Records: To be eligible for a record, you must be using stock parts. Also, for atmospheric records, you must not switch to Closed Cycle on RAPIER engines, these are for air-breathers only.

Records will come from a screenshot of your F3 window.

First to Complete Challenge : Lego8_bit with Lizzard. 2,081m, 183m/s, 19.469km

Altitude (highest) : 28,856m - K3achas with Demonic Goat Cheese Consiar

Speed (highest) : 1,194m/s - K3achas with Demonic Goat Cheese Consiar

Ground Distance Covered : 4,454.042km - noname117 with NAM-6

Kerbin Orbit and Beyond: This challenge specifies air-breathing engines only, including RAPIERs in air-breathing mode only. So, I don’t expect to see anyone reaching orbit or heading off to Moho in air-breathing mode. However, it is probably possible to reach orbit with a RAPIER switched to closed cycle. The failed RAPIER should remain failed throughout the flight of course. Switching a RAPIER to Closed-Cycle for any period of time makes you ineligible for the atmospheric records. If you choose this route, you need to leave the remaining RAPIER at full throttle, in air-breathing mode, until you reach 1,000m. After 1,000m you may throttle down and/or switch to closed-cycle as you wish. Not sure how to set up this leaderboard yet, I might just list entries and their accomplishments.

V1 Cut concept: Commercial aircraft are designed to be able to continue to operate safely in the event of an engine failure during any phase of flight. The most challenging phase to lose an engine is during takeoff. The plane must be able continue the takeoff, and maintain sufficient climb to clear terrain or obstacles. During takeoff, the aircraft is going slow and close to the ground, so there is not much room for error.

One challenge to losing an engine during takeoff is the significant yaw moment produced as a result of the asymmetric thrust. Commercial aircraft are designed so that it is possible to overcome the asymmetric thrust through the use of rudder and possibly banking slightly into the good engine. While reducing thrust on the good engine would reduce the asymmetric thrust, this is not an option for an aircraft which is trying to clear terrain. You already lost half your thrust when the other engine failed, now you need every ounce of thrust the good engine can produce.

The term ‘V1’ is sometimes referred to as Takeoff Decision Speed. At speeds below V1, the aircraft is capable of aborting the takeoff and stopping on the runway in the event of an engine failure (or other problem). At speeds above V1, the aircraft is capable of continuing the takeoff safely even if an engine failure occurs. Generally, once an aircraft has reached V1 speed during the takeoff roll, the takeoff will be continued regardless of what components fail.

An engine failure right at V1 produces the biggest challenge during takeoff. This is the slowest speed an aircraft could be going and still continue the takeoff. The slow speed results in poor climb performance. Additionally, the slow speed means the rudder is not very effective at counteracting the adverse yaw from asymmetrical thrust.

Commercial pilots are trained on a recurring basis to address various abnormal conditions, including engine failures. As the most challenging time to have an engine fail is right at V1 during takeoff, engine failures at V1 are practiced regularly (usually in a simulator). These are referred to as ‘V1 Cuts’.

Edited October 9, 2015 by RexKramer

[SpaceplaneAddict]

Lol, as soon as I saw this, I was laughing like a madman. Why? Because my fighter aircraft successfully evaded another fighter with only 1 engine out of two. I WAS using FAR at the time, so does that invalidate this? Because you never said anything about physics(aero) changes by mods. Maybe a seperate leaderboard for FAR would be nice? 'Cause, I ain't lyin', my fighter pulled 10G at Mach 1(average) with an engine lost.

[RexKramer]

Here are a couple of examples of successful designs. I don't use joysticks, so this is all with a keyboard to control the plane.

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I WAS using FAR at the time, so does that invalidate this? Because you never said anything about physics(aero) changes by mods.

Yes, FAR alters stock physics, which is not allowed- see the section on MODS: "The use of any mods which alter stock parts, or add non-stock parts, or alter stock physics, is not allowed."

With that said, entries which use non-stock parts or physics (like FAR) are fine, they just won't be eligible for the records. That keeps a level playing field for everyone else. So anyway, feel free to post your attempt, just make a note of mods you are using.

Edited September 15, 2015 by RexKramer

[Lego8_bit]

ok these are excellent examples im gonna build a plane real quick and ill give this challenge a shot

[Rath]

Somebody build a SSTO that can do this!

[RexKramer]

Somebody build a SSTO that can do this!

My third example is actually my go-to SSTO, which ferries 8 Kerbals to and from LKO. I haven't tried limping it to orbit on one engine. I'm confident it won't take long for someone to accomplish this feat however.

[Lego8_bit]

ok heres my plane i dubbed it the lizzard....

\/\/\/\/\/\/\/UPDATED PLANE\/\/\/\/\/\/

The following pics are in order on how the plane handeled the failure....

https://gyazo.com/f296861174f8adb9128be9da9d6bf7f1

https://gyazo.com/2f45227507d9a4421cb545b541f3a59f

engine failure

https://gyazo.com/36ca38568ec36f230515d43fcfa74f32

https://gyazo.com/bbd4a41653d1b90a8e5763482f68975e

HEIGHT ACHIEVED...

https://gyazo.com/9fbf143d88b359f95b90b1eaf8a15af2

U TURNS!!!

https://gyazo.com/29d7b097f9931a9558be84ded4fecf94

https://gyazo.com/f86f5ee1bd9a50daf6e241d531aa515b

https://gyazo.com/33a697405c283ef5814e23400a0e0ae6

Final turn and landing results....

https://gyazo.com/381ed666af306d2ab1e4367ae1a87f4d

https://gyazo.com/bd22177ee1e1aa50ad379c7a2167c1c3

https://gyazo.com/90d0585b0fe5bb1bbd063e89659105d1

Results!!!!

https://gyazo.com/8a4d4cbb20d7003fd5869cecd356678e

Edited September 15, 2015 by Lego8_bit

[RexKramer]

Well, I thought I was going to have to disqualify the first entry, by Lego8_bit, because of the third engine mounted above the first two. Wait, that's not an engine, it's an intake pod, with 3 different intakes! Awesome! Nice job, Lego8_bit, and congratulations on being first! Bear with me, this is my first challenge, as soon as I figure out how to edit my post I'll add you to the leaderboard.

By the way, while I specified that you needed exactly two engines, no more and no less, I didn't say anything about how many intakes needed to be on the plane or where they need to be. Very interesting design.

[SpaceplaneAddict]

Can I have more points if I have no reaction wheels, no RCS devices, and on top of that, I do some crazy stunts?

[FlipNascar]

This brings back memories for me....

So, wanting to see if I could do this with a) beauty replica c) already built... I grabbed my Mik-29 (download link if you want your own). And have duly completed the challenge. She's pretty, but she's also very draggy.

Not stellar in anyway whatsoever. If I had the patience to burn more fuel and more refined ascent profile I think I could probably add to its figures...

2,127m, 137m/s

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If you're designing with this challenge specifically in mind... Do the jet engines have to be identical? Can I have one Wheesly and one Rapier? Because if you can do that, and then you can place the Wheesly off centre, and with it's lower mass, there's less of a yaw effect if you design around the "good" engine... Anyways, with my Cheaty design on first flight we hit 10km and about 385m/s. Needs more yaw stability to get more Mach.

[OV-099]

Hmm... Seems interesting. I shall try it when i have time.

[RexKramer]

FlipNascar, your Mik29 looks great.

Regarding your 'cheaty design', yes that goes against the rules in a couple of ways. First, the two engines really should be the same. If not, you would really need to kill the weaker engine, and leave the stronger engine running at full throttle 100% to 1,000m.

Also, technically the rules state engines mounted laterally. Mounting one of the engines on the centerline goes against the basic idea of the challenge.

These are all excellent ideas, creative ways to sidestep the basic controllability problem this challenge presents. I was actually hoping to see some creative solutions to the problem, even ones which violate a rule or two.

I'll add Mik29 to the board later.

[SpaceplaneAddict]

Badge, and I will work like a madman.

[OV-099]

Just wondering, is it against the rules to make the ENTIRE ENGINE come off? Like what happened with American Airlines Flight 191?

[FlipNascar]

Just wondering, is it against the rules to make the ENTIRE ENGINE come off? Like what happened with American Airlines Flight 191?

I like the way you think. I was contemplating the same thing....

In a further stretching of the rules and creatively interpreting them....

Not a valid entry because I had to add fuel with hyperedit to make it back to the Island runway... Like 14 units

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Technically, a legal entrant...

Edit: Just read rule 6... Don't actually have to land... Er in that case

From the first flight, before I added extra landing gear and canards to make it easier to land...

Edited September 15, 2015 by FlipNascar

[RexKramer]

Just wondering, is it against the rules to make the ENTIRE ENGINE come off? Like what happened with American Airlines Flight 191?

I wanted to say no, but honestly the rules don't prohibit this. In real life, it's not uncommon to jettison fuel in an emergency, why not jettison the junked engine too? So yeah, feel free to jettison the engine. This could easily happen with pylon mounted engines. However, I think it would not be reasonable to jettison engines mounted on bi-couplers on the back of the plane (although the rules don't prohibit this either.

Come to think of it, parts falling off vessels is kind of expected when it comes to Kerbal vessels, at least with mine..

[Azimech]

If dropping an engine is not allowed I'll redo it. But I started from almost zero speed on the runway and dropped the engine. But, since we're talking parasitic drag, the nacelle with prop stayed.

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I can upload it, anyone can fly this thing and land it in one piece.

And I could upload a video.

[RexKramer]

In a further stretching of the rules and creatively interpreting them....

Not a valid entry because I had to add fuel with hyperedit to make it back to the Island runway... Like 14 units

http://imgur.com/a/rv0HE Technically, a legal entrant...

LOL. Sorry, I'm going to be a stickler on the 'Laterally Mounted' part, a bi-coupler rotated so the thrust of one engine is slightly higher than the other one isn't going to pass muster.

[FlipNascar]

.....snipped

Rules:

2. Engines must be mounted laterally, or one on each side of the aircraft. In other words, not mounted with one above the other one. The asymmetric thrust must produce a yaw moment, not a pitch moment.

3. The horizontal distance between the engines is up to you. Mounting two engines right next to each other on a bi-coupler at the back of the plane is perfectly fine. Mounting them on pylons on the side of the fuselage or under wings is fine. Clipping so that the engines overlap is not allowed.

LOL. Sorry, I'm going to be a stickler on the 'Laterally Mounted' part, a bi-coupler rotated so the thrust of one engine is slightly higher than the other one isn't going to pass muster.

'tis in the rules... ! I'll just twist the wings a bit more instead then.

[RexKramer]

If dropping an engine is not allowed I'll redo it..

No need to redo, parts falling off is the Kerbal way.

Azimech, can you confirm the 'propellers' are not modded parts, but actually flight control surfaces mounted to nose cones? If so, your entry looks completely stock, and meets all the specified rules.

[Azimech]

Those are antennae.

Here's the airplane :-)

http://kerbalx.com/crafts/5283

[FlipNascar]

Fixed it...

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[Starwhip]

Fixed it...

http://imgur.com/a/Z28Xv

I had the exact same idea.

I wanna try this with a horizontal plane though.

[Noname117]

Decided to try this with a NAFA-4-J2 Strike Cobra. I took off with it, cut one engine, and just kept flying. I'm glad you mentioned we could land anywhere.

I didn't get an F3 screenshot at the end because I did have to quicksave/quickload in flight a couple of times, but I did get one in flight after I had reached my top speed and altitude and before I had quicksaved. Use those values.

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[Azimech]

69 pictures? Why not 70? One more, make sure he gets a clear picture of you flight.