A-50 flying on one engine? uhhh...

[Shein]

Alright so I've done the awacs hunt mission (03 of bear trap campaign) about 20 times now. Most of those times, I got killed.

The most recent time, I managed to get a shot at him. For good measure and because I was angry, I shot 2 amraams at him.

They both hit, taking 3 of his engines off.

 

I broke away and ran from his angry flanker buddies, and a mig29 also gave chase to me.

I managed to kill the mig and the flankers gave up. I landed back at base and used the F2 view to see what happened to the A50.

 

He was limping back to base on 1 engine, still on fire, but he was bleeding airspeed and altitude. I dry washed my hands, watching what I thought would be him bleeding airspeed until he stalled but no. He got all the way to an airport, slowed to 96 knots, climbed 300 feet for the glideslope, and landed safely. It was at this point I let out a string of curses the likes of which I didn't even know I had in me.

 

not sure if this belongs in the bug section or not, but I see a few problems:

1. I know the warheads were changed in the most recent patch. But are they that weak?

2. I don't think an A-50 can fly on 1 engine. is degraded thrust modeled for aircraft that lose engines?

3. do larger aircraft have a more simplified airframe damage model? because I would think that if he lost 3 engines (I mean detached from the pylon lost) he would have some pretty severe airframe damage as well.

 

What do you guys think?

And laughs at my misfortune are also welcome. :doh:

[kk0425]

Well, I can say at least the AIM-7 is still hitting hard.

[KLR Rico]

And laughs at my misfortune are also welcome. :doh:

 

Laugh, I did! But only because I have shared your misery. Not with the A50 in particular, but in other situations, and I was amused by your account of the familiar situation. :D

 

There are definitely some issues with some of the SFM aircraft. I hope they're on what must be an incredibly long to-do list, but may be tuned up in the future.

[KLR Rico]

Well, I can say at least the AIM-7 is still hitting hard.

 

 

:megalol: I'll say!

[EtherealN]

2. I don't think an A-50 can fly on 1 engine. is degraded thrust modeled for aircraft that lose engines?

 

Can't say for 100% about the A-50, but I will say that I have never heard of any multi-engine aircraft that is incapable of flying on one engine*. Typical safety feature is that the aircraft must be able to maintain altitude even if all but one engine are lost. (If this is not possible in a given design, they uprate/replace the engines to a type that will afford this capability.)

 

3. do larger aircraft have a more simplified airframe damage model? because I would think that if he lost 3 engines (I mean detached from the pylon lost) he would have some pretty severe airframe damage as well.

 

Non-human aircraft have a simplified damage model.

 

Hard to say for real sure what's going on here without the track though. :)

 

*Well, aside from really really old stuff like the Spruce Goose and stuff.

[PE_Tigar]

@EtherealN - flight in this case might mean a downward part of the ballistic curve. There's nothing preventing a 4 engine airplane from flying (gliding) even with all engines out :). In no way should it be able to climb on one engine, at 96kts though...

[Davros23]

Can't say for 100% about the A-50, but I will say that I have never heard of any multi-engine aircraft that is incapable of flying on one engine*

 

I'd like to see a B-52 flying on one engine! :)

[SNAFU]

Can't say for 100% about the A-50, but I will say that I have never heard of any multi-engine aircraft that is incapable of flying on one engine*. Typical safety feature is that the aircraft must be able to maintain altitude even if all but one engine are lost. (If this is not possible in a given design, they uprate/replace the engines to a type that will afford this capability.)

 

Isn´t that only applicable for 2 engine aircrafts? Given the 1-engine-failure-during-takeoff design principle for the thrust specifiations of 2 engine aircrafts, leading to generally overpowered turbo-fans for 2 engine aircrafts in comparison to 4 egnined aircrafts?

[EtherealN]

@EtherealN - flight in this case might mean a downward part of the ballistic curve. There's nothing preventing a 4 engine airplane from flying (gliding) even with all engines out :). In no way should it be able to climb on one engine, at 96kts though...

 

Note that I didn't speak about climb. I responded to the specific question of "flying" on one engine.

 

As already mentioned, damage models for AI aircraft are necessarily simplified, but on the specific question of an A-50 being able to fly on one engine: I think it can.

 

A-50 has MTOW around 170000kg. 4 engines of 157 kN each.

Boeing 747-100 has empty weight 333000kg, 4 engines of 207 kN each.

 

Thus, on one engine:

A-50 has 0,92 kN per metric tonne MTOW.

747-100 has 0,62 kN per metric tonne MTOW.

 

And we know the 747 can maintain altitude just fine on one engine (it was a specific requirement for the engine choice). Thus it makes sense to assume the A-50, which has so much more power per tonne, can as well. (Though of course there is a lot more that goes into this, but just to indicate that it is not at all difficult to assume that it can indeed fly just fine on one engine.)

 

Climbing is another matter, and one I didn't discuss: as mentioned, damage model for AI aircraft is necessarily simplified, as is the flight model. Otherwise this simulator wouldn't run on a home computer. ;)

[Speed]

I find it very implausible for that A-50 to be able to fly as described. It's an A-50, and it has this giant, draggy radar dome on top. And furthermore what engine was it that he had left? If it was one of the outer engines, then he should have been a huge thrust imbalance, causing him to yaw badly when he applied power. Now, he could have corrected that with rudder maybe, at higher speeds, but at just 96 knots I doubt the rudder would have the control authority to override the thrust imbalance, even if it was one of the inner engines. Furthermore, all that applied rudder would have further increased his drag.

 

It is important to keep in mind that the AI does fly a much simplified flight model. If they didn't then your computer would quickly bog down trying to compute all their flight parameters, and you would need very elaborate and complex control algorithms to make them fly the plane correctly.

 

So this would probably be a place where the AI needs some tuning in some regard.

 

Anyway, it's not implausible at all though, that an aircraft like the A-50, reduced to a single engine, could keep its airspeed high, and use the thrust of that engine to get it to the nearest airfield. I just don't think he could actually USE that engine during landing, I think he would probably have to just glide it in, because at slower speeds, the effect of the asymmetrical thrust would be too much for his rudder to compensate.

 

Keep in mind though, I'm just an armchair pilot, so anyone with better knowledge feel free to correct me.

[Speed]

The only time I know of when a big aircraft was hit by multiple missiles was when the Soviets shot down Korean Air flight 007 (a civilian Boeing 747) in 1983. The Su-15 fired two R-8s, and according to the Soviet pilot, both missiles hit their mark. The pilots of the 747 were actually able to fly the aircraft for a little while but eventually lost control. So maybe it's not entirely implausible for something like the A-50 to survive two missile hits- but it should be a RARE occurrence. And I would imagine (or at least, hope) that the warhead on an AIM-120 would be more deadly than the one on an R-8.

Edited March 15, 2013 by Speed

[Shein]

Well, I can say at least the AIM-7 is still hitting hard.

 

Now did he limp back to base like that?! :megalol:

 

I'm a civilian pilot IRL and I always thought the larger aircraft were rated to fly on 2, but not just 1... though seeing the numbers, I think you're right Ethereal. That's embarrassing! :doh:

 

If I get another shot at him I'll give him every missile on my rails.

 

And yeah it was an outboard engine that was left. If he had planned his driftdown properly I could see him gliding to an airbase with that one engine but I tend to think the adverse yaw and associate drag would make it tough for him. But I know, human factors aren't modeled... (not that I'm complaining)

[EtherealN]

Well, there may very well be finer points to the concept of "maintaining altitude"; I haven't dug into performance per altitude etcetera, so I'm not sure at what altitudes they are required to be capable of this.

 

Had this been a few weeks earlier I would have asked the 747 pilot I was talking to back then at the hotel, but ah well. :/

[EtherealN]

It's an A-50, and it has this giant, draggy radar dome on top.

 

707-320B MTOW is 151320kg (wikipedia, I know)

E-3 MTOW is 157000kg.

 

The 707 gets ~0,56 kN on the one engine per metric tonne.

The E-3 gets ~0,59 kN per metric tonne.

Engines uprated thus by about 5% versus the increased weight. (Whether to compensate foir the radome? No clue.)

 

Il-76 gets ~87 kN on the one engine per metric tonne.

A-50 gets ~92 kN per metric tonne.

 

Figures from wikipedia, so who knows. But interesting point here is that Il-76 has a stronger engine than the A-50, but a much higher weight. (Empty: 92 500kg for Il-76, 75 000kg for A-50)

 

What then happens with the aerodynamics... I don't quite dare venture into, but the numbers are interesting I would say.

[KLR Rico]

Isn't any plane flyable on one engine, or no engines for that matter?

 

It's just a matter of having enough airspeed and altitude to make it to the crash site. :D

[Cali]

I'd like to see a B-52 flying on one engine! :)

 

Lmbo, it wouldn't go anywhere but down. The engines only produce about 17,000 lbs of thrust. Saw one take off the other day with 300k of fuel onboard and we were scared for the pilots. The left wing was low, the right wing was high and this was when it started it's take off roll down the runway. The jet only holds 312k of fuel, the most I've seen on before the other day was a 280k load.

 

The Aussy Airbus A330 MRTT only has 2 engines, but they are freaking huge! I wonder how flying it with one engine would be like. It's a tanker and can hold 380 passengers. Wish I could have taken pictures of the inside and of the air crew :) they were sexy looking.

[Eihort]

Figures from wikipedia, so who knows. But interesting point here is that Il-76 has a stronger engine than the A-50, but a much higher weight. (Empty: 92 500kg for Il-76, 75 000kg for A-50)

 

You mean to tell me that an empty cargo plane weights substantially more than it's AEW cousin with no fuel? That makes absolutely no sense even if the engines are better.