Engine out emergency autorotation landing

[geogob]

I've been practicing autorotation landing and descents a bit. I have no trouble doing a roll-out landing or a vertical landing (both on hard ground and soft ground) with the engines at set at Idle while in autorotation. Everytime, I'm able to do a landing with impact well within 3 G.

 

Even though I have no knowledge of emergency procedures with the KA-50, I then decided to try engine-out auto rotation landings, with both engine off. I never get it right.

 

First, i'm maintaining rotor RPM stable is much more difficult. I can't stabilize the airspeed nor the decent rate. Finally, the rotor slows down much faster during flare and does not transfer enough horizontal velocity to lift. Conclusion, autorotation landing with engines out always results in crashes.

 

Are there differences in the procedures for engine out autorotation landing? Are the V speeds the same in that configuration? What am I missing? Should the horizontal speed be greater than 120 kmph to compensate for the lack of idle power imput to the rotors?

[diveplane]

first of all are you trying this with external weapons and how much fuel?

i would start to practice this with a clean aircraft and 25% fuel.

[Sunjah]

This is why I play! I remember the old Microprose game, "Gunship," and I read that manual thoroughly and understood a lot about that sim. I remember once having my rotors damaged, and I had to do an autorotational landing...AND I DID IT, in the heat of battle.

 

If you quizzed me on the procedure, I'd remember 0% except that it was "by-the-book {manual}" as far as auto-rotational landings go. I remember quite specifically, a few seconds after being shot and losing the rotors, staring at the screen and saying to myself, "I know how to do this, it is an autorotational landing I need to perform," and I did even while in the midst of an active battlefield.

 

That was such a rush, I will never forget it, probably about 20 years ago.

[geogob]

first of all are you trying this with external weapons and how much fuel?

i would start to practice this with a clean aircraft and 25% fuel.

 

Using exactly the same configuration (I had full weapon load, 75% fuel), I have no problem doing the decent and landing in a field with engines at Idle, but not with engines off.

 

I did not jettison my weapons first. I'll try that to reduce the weight as much as I can.

[LIONPRIDE]

first of all are you trying this with external weapons and how much fuel?

i would start to practice this with a clean aircraft and 25% fuel.

 

Good point. Make sure to jettison whatever you can (if time permits), bottom out your collective and get some fwd speed. The rest is just figuring out when to flare. Try it at altitude first a couple of times.

 

 

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[geogob]

That I understand all perfectly. What troubles me is that I am perfectly able to do an autorotation landing with the engines at ideal. I'm able to do it without any trouble regardless of the aircraft load or the flight configuration when switching the engines at idle. Maintaining desired IAS, vertical speed, course, rotor RPM and flaring is not a problem at all. Heck! I can even select which field I like better for my landing :music_whistling:

 

That tells me that I understand and master the procedure fairly well. On the other hand, all attemps with engine out failed. That's why I though there might be difference in the procedure or in the required speeds. After all, the power output from the idle engines is not negligeble.

[geogob]

I noted that every time I try an engine out, the rotor RPM warning continuously beeps and flashes. It never does that with idle engines. Is this normal? In both cases I maintain the RPM at the minimum save value. Maybe it stays just below it with engines out.

 

In the in-game training, I think it says to maintain rotor RPM at 90%. I have no clue how one can achieve such a high RPM in auto rotation. I didn't manage that, even with the collective full down... Could it be a triming issue?

[AlphaOneSix]

Well, I did a tests a while back where I left the engines at idle and I was able to take off with full fuel and four full wing tanks. Of course, my rotor RPM dropped low enough to kick off the generators, but it flew.

 

In the "real world" you'd never turn the engines off, but then again, you don't auto all the way to the ground, either...it's really just about technique. In-game, it's more important to go all the way to the ground to make sure you have your technique down, so I'd say practice with engines at idle just to get the general idea, but for real practice, just shut them off. In the game it doesn't matter if you bend up the bird practicing. ;)

[Yo-Yo]

I noted that every time I try an engine out, the rotor RPM warning continuously beeps and flashes. It never does that with idle engines. Is this normal? In both cases I maintain the RPM at the minimum save value. Maybe it stays just below it with engines out.

 

In the in-game training, I think it says to maintain rotor RPM at 90%. I have no clue how one can achieve such a high RPM in auto rotation. I didn't manage that, even with the collective full down... Could it be a triming issue?

 

 

You must only maintain RPM near the low margin. It's safe. Maintain 120-130 kph and your RPM when collective is at the bottom will be near this value.

The main problem I know at autorotation is yaw rotation.if you bleed the speed without increasing collective you encounter unconrolled yaw rotation.

That's why the most hard is to coordinate collective and pitch-up attitude change while flaring.

But there is a good chance to safe landing sometimes with tires blown away or rudder damage.

[LIONPRIDE]

.

 

Are you using the quick-engine kill ? [Win]+[Home] keys ... ? I wouldn't use that option. Sounds like you're not though.

 

Are you making sure you haven't engaged the rotor-brake as well?

 

Just a couple of quick thoughts ...

 

 

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[geogob]

I'm simply closing the cut-off valves to shut the engines down. Hehe, I'd never even think about using the cheat short-cuts ;)

 

Also I understand this is not something you normally do. I'm practicing it so I know what to do if both engines fail due to damage.

 

Honestly, the way it is now, I would not only rip the gear off, but probably break the bird in two at impact.

[miguez]

Hi geogob,

 

A better way to practice would be to create your own mission with both engines set to fail in between 5 and 10 minutes, for example. that would give you enough time to get in the air, start moving somewhere, but not know exactly when the engines would fail. It creates a little more realism for this scenario.

[AlphaOneSix]

Excellent idea, making a seperate mission. One thing to keep in mind: If you use the in-game malfunctions, it actually causes an engine fire, and does not simply shut down the engine. The first fire bottle will fire automatically and put out your first engine, and you can keep flying. When the second engine fails, the second fire bottle will have to be fired manually. So after the first failure, once you get things under control (i.e. fire out, which should be automatic, shut off the failed engine fuel cutoff lever, increase throttles to EMERGENCY, and make sure you don't crash in the process), you should switch your fire bottle switch over to your alternate fire bottle, and when the second engine fails, you will have to click the failed engines fire button to put it ou, plus cut off the fuel lever, plus drop your collective and begin your autorotation. (You could probably skip the fuel lever, but in real life that absolutely needs to happen so you are not feeding fuel to a hot engine that was just on fire.)

[ThunderChief]

When I tried autorotation (with engines off) i only got it right with high forward speed, (60 kph at least).

 

If I tried a conventional flare I would crash, tail first impact. I guess its to much armor for a lowspeed autorotate landing, it is simply to heavy...

[miguez]

If you use the in-game malfunctions, it actually causes an engine fire, and does not simply shut down the engine.

 

Can you tell I have not tried the in-game failures yet? :).

 

That's too bad, one thing I'd really like to see in BS is extensive failure modeling, where you could program each individual instrument for failure, if needed/wanted/required. That would add a lot of realism, having to finish off combat without an ABRIS, or navigate in poor weather on the standby ADI due to main ADI failure, etc.

 

Maybe crossing our fingers will make ED add it to future updates?

 

AlphaOneSix, thanks for the explanation, great stuff.

[geogob]

Good idea for the failures. I already have a custom mission to practice autorotations. I'll add random failures :)

 

Thanks for the excellent idea. But first thing first. Lets master this in a control situation when I know it happens. Then, when I get it right every time, it's time to do it with the failure system. And once that is done and master, i'll be ready to do it in case of emergencies while I fly the sim for real.

[heloguy]

When I first purchased this sim, after trying a few patterns and getting used to the controls, I decided to try an auto. Looking around for something that would kill the engines (hadn't printed out the key list yet), I found the fuel selectors and decided to use them to cut fuel turning base to final.

 

The engines died quickly, so I immediately lowered the collective, and brought the airspeed back from 250kph to 200, as I figured this was close to a good auto speed from blackhawks (comes out to about 107 knots, we usually use 100 knots).

 

At about fifty feet I flared, adjusting the collective only enough to keep the rotor within limits, not attempting to cushion yet. In a fully-articulated head such as the Shark's, inertia is a problem, so you don't want to start adding collective too early.

 

The decel seemed to arrest the rate of decent nicely, and as she started to fall through, I leveled her out, and applied collective smoothly to it's fullest position. You definitely want to land in a flat profile as this allows the gear to absorb the shock.

 

I thought I had broken the gear off surely, as I wasn't used to the attitude on the ground yet, but an outside view revealed all was well, although I'm sure my virtual pilot needed to change out his flight suit. Anyway, hopefully that description can help someone. There are all sorts of different techniques, that one is mine.

 

Just make sure you don't add collective too early. I can't stress that enough. If you add so much that the aircraft starts to rise, it's too much.

[geogob]

Yes, I think I pulled the collective too much and too early. I guess it's a natural reflex you need to overcome...

[ericinexile]

1) Make sure brake is off

2) Follow advice in posts above also remembering to get aligned with zero side-slip. Do this by:

 

a) Use yaw to keep longitudinal axis PARALLEL with runway or desired LZ.

b) Use bank to control left/right position over the runway. (ignore the ball)

 

3) Trim (FD on for me)

4) Flare moderately at 40-50m (this not only kills speed and descent rate but also stores energy (RPM) into the rotor system which erodes rapidly when...)

5) As soon as helo begins to sink, simultaneously feed plenty of collective and apply cyclic so that attitude is level just prior to touchdown. Save that last 20 percent of collective for a hard pull at the last meter.

 

The Ka50 (as simulated) just might have the worse autorotation characteristics of any helicopter flying. Small rotor diameter perhaps?

 

Smokin' Hole

Autorotation.trk

Edited January 22, 2009 by ericinexile

[uhoh7]

I have to say that is pretty fun. Never tried before. Hit both cutoff levers. Made it down several times on runway before I figured out I could pull the coll to settle.

 

Last attempt, I forgot to lower gear, put down to the side of the road so gently on my belly, I was able to fire back up, take off and land again at runway, rear gear would still go down, but I had lost the front gear. Did get a transmission warning.

[eV1Te]

Is it possible to do an autorotation landing with the engines off and with a realistic amount of gas/weapons etc. and by the time the wheels touches the ground the horizontal speed should be 0 km/s. If so please upload a track file which shows how it's done

 

(This is necessary if you make an emergency landing in rough terrain)

[CAT_101st]

Well the weapons would be jet off the wings ASAP so just fule would be the problem. All the missions I make have just enough fuel on board to compleat the mission. This saves weight if flying in mountans.

[uhoh7]

In my practise I was clean, 15% fuel. I'll have to try it loaded.

[eV1Te]

Well the weapons would be jet off the wings ASAP so just fule would be the problem. All the missions I make have just enough fuel on board to compleat the mission. This saves weight if flying in mountans.

 

Yes, but still the Vikhr launch tubes is still there, how much does they weight? Also the Cannons ammunition weighs almost 500 kg should you fire them of as well?

 

Even if I use only a small amount of fuel and no weapons I can not make a stand still on the spot autorotation landing...

[AlphaOneSix]

12 Vikhr missiles, plus launchers, weigh between 600kg and 660kg. Drop the 12 missiles, and the two empty launchers weigh 120kg.