Have I got a power problem?

[ronvking]

Just purchased A-10C and very pleased however I find that I can't seem to get the performance from the aircraft I would expect.

 

On an aircraft just with internal fuel I can only get it up to around 17000 ft and no further before she stalls. I notice that the throttle did not seem to go fully forward and the fan speed indicator never rises above 82 percent.

 

I've tried another joystick where the throttle appears much better but still only get climbs to 17000 before running out of power.

 

When looking at the throttles in the game it looks like they dont go to the far end of the available movement but even the keyboard command wont pust it further.

 

Have I got a problem or just missing something out?

 

Thanks Ron

[EtherealN]

Fan indicator never goes above 82% unless something is wrong - that is the optimal setting on that engine.

 

Climbing depends entirely on how you do it. What is your climbing speed? You should do it around 180 knots indicated. If you slow down below that in an effort to force the nose up, you lose climbing ability.

[Eddie]

Best climb speed in the A-10 is 200 knots indicated - 1 knot per 1000 feet above MSL. So at Sea level your best climb speed is 200 KIAS, at 10,000 feet it's 190 KIAS and so on.

 

The biggest mistake people make in the Hog is trying to force the climb, it's especially common in people who've come over from fighter sims. She will climb to 35k quite happily, but she won't do it quickly.

[EtherealN]

And here Eddie comes along displaying for everyone how rusty I am with the A-10... :D

[ronvking]

Unusally for me I have been reading the manual and climbs have been around 170-200 kts.

 

When I've got to around 15000 the speed has fallen to a low figure and the nose angle is about 2.5 degrees, any higher and she stalls. Again at that height the rate of climb is barely 500ft a min.

 

Cheers Ron

[GGTharos]

You're doing something wrong . Track please.

[Eddie]

Then you must either be trying to climb too quickly, or be carrying a excessively heavy payload.

 

Trust me, 30k and above is easy to reach, if you do it right.

 

[luza]

Eddie how do u get the Bullseye on your Hud? seems handy, guessing it's a setting in IFCC? :)

[Intruder_360]

Eddie how do u get the Bullseye on your Hud? seems handy, guessing it's a setting in IFCC? :)

 

Set your cdu page rotary to waypoint and select "anchor pt" on the right mfd, than you can see on the left "hud on/off", this is for to show the bullseye on the hud.

 

regards Intruder

[ronvking]

One track as requested.

 

Got up to 18000, throttles as far forward as my system would allow. Level flight, no payload and by then down to 9900lbs fuel. By this time my IAS was 163kts after 5 min level flight.

climb.trk

[Eddie]

One track as requested.

 

Got up to 18000, throttles as far forward as my system would allow. Level flight, no payload and by then down to 9900lbs fuel. By this time my IAS was 163kts after 5 min level flight.

 

Well after viewing your track it's not surprising. You can't just stick path hold on and then sit there fat, dumb and happy and expect the jet to do the climb for you.

 

As I said above, best climb speed is 200 KIAS minus 1 knot per thousand feet. You let the jet sail right below climb speed and do nothing at all, so it's no surprise that you end up stalling. Set and adjust your pitch to maintain the best climb speed.

[Eddie]

And by way of a demonstration that I (we) are not making it all up, attached is a track of a flight from the runway to 30,000 ft MSL and back to the runway.

0 - FL300 - 0.trk

[GGTharos]

Yep... this sort of profile has to be flown by the fast-movers too if you want an efficient climb ... learn what Eddie is showing you, because it applies to all aircraft.

[EtherealN]

By this time my IAS was 163kts after 5 min level flight.

 

That's the thing though - you are letting your speed get to low.

 

When we say you have a climb speed, we don't mean "start here and then just let it be". You got too slow, lost your lift, and thus cannot climb.

 

 

L = Cl * A * ½ * r * V²

 

Where:

L = Lift

Cl = Coefficient of lift (basically your aerofoil(wing) characteristics)

A = Aerofoil area

½ = constant

r = density of the medium - that is, air. You can (simplified) think of it as "altitude"

V = velocity, as absolute (or "true")

 

Note how V is squared. This makes it the "big deal" here. Low speed will thus have a MASSIVE impact on your lift, and thus your ability to climb. For example (with fictional numbers:

 

L = Cl * A * ½ * r * V²

 

100 000 = 2 * 2 * ½ * 5 * 100²

90 250 = 2 * 2 * ½ * 5 * 95²

 

Note how a very small (5%) downward change in the V factor caused a loss of almost 10% of your lift.

 

If we apply the optimal (200 - though this is still simplified, see Eddie's post) and you actual:

 

400 000 = 2 * 2 * ½ * 5 * 200²

265 690 = 2 * 2 * ½ * 5 * 163²

 

As you can see, you robbed yourself of almost half of your lift through letting yourself get slow!

 

EDIT: Just to be clear, the numbers here are "fake" and used just to illustrate the dynamics of the equation. I don't have the "real" numbers on hand, and the r factor will change depending on conditions.

Edited July 27, 2012 by EtherealN

[Loki_]

That's the thing though - you are letting your speed get to low.

 

When we say you have a climb speed, we don't mean "start here and then just let it be". You got too slow, lost your lift, and thus cannot climb.

 

 

L = Cl * A * ½ * r * V²

 

Where:

L = Lift

Cl = Coefficient of lift (basically your aerofoil(wing) characteristics)

A = Aerofoil area

½ = constant

r = density of the medium - that is, air. You can (simplified) think of it as "altitude"

V = velocity, as absolute (or "true")

 

Note how V is squared. This makes it the "big deal" here. Low speed will thus have a MASSIVE impact on your lift, and thus your ability to climb. For example (with fictional numbers:

 

L = Cl * A * ½ * r * V²

 

100 000 = 2 * 2 * ½ * 5 * 100²

90 250 = 2 * 2 * ½ * 5 * 95²

 

Note how a very small (5%) downward change in the V factor caused a loss of almost 10% of your lift.

 

If we apply the optimal (200 - though this is still simplified, see Eddie's post) and you actual:

 

400 000 = 2 * 2 * ½ * 5 * 200²

265 690 = 2 * 2 * ½ * 5 * 163²

 

As you can see, you robbed yourself of almost half of your lift through letting yourself get slow!

 

EDIT: Just to be clear, the numbers here are "fake" and used just to illustrate the dynamics of the equation. I don't have the "real" numbers on hand, and the r factor will change depending on conditions.

 

Tl;dr

 

You're too slow.

[EtherealN]

Yes, I was trying to illustrate WHY that is a problem. ;)

[ronvking]

Tl;dr

 

You're too slow.

 

I know I'm too slow, thats the point I've been trying to make. Look on that track, at the end I level out and run for a while at 18000 ft and the speed never increases much above 163 kts. Now according to Eddies information I should be climbing at or around 180 kts but I can't get the aircraft to go that fast.

 

On what everyone saying I should not run out of steam like that should I?

[EtherealN]

Yes, you should.

 

If you run out of steam due to being high and slow, trade some altitude for speed to get yourself some new speed, and then make sure to keep it. ;)

 

EDIT: I'll try to explain it like this; when you are slow you need a high angle of attack to maintain your altitude. This means you have more drag. At the same time, going up high reduces your engine thrust. What you are seeing is those two converging. Solution is to either trade altitude for speed, or to never get yourself into that situation in the first place. The second is the ideal, but of course everyone does end up there a little now and then for _some_ reason. Skill is in makming sure this happens as little as possible.

Edited July 27, 2012 by EtherealN

[Eddie]

I know I'm too slow, thats the point I've been trying to make. Look on that track, at the end I level out and run for a while at 18000 ft and the speed never increases much above 163 kts. Now according to Eddies information I should be climbing at or around 180 kts but I can't get the aircraft to go that fast.

 

On what everyone saying I should not run out of steam like that should I?

 

The only reason you're running out of steam is that you're not flying the jet. As I said, you can't just set a pitch angle, open the throttle and expect the jet to climb all by itself with no further input.

 

Watch my track, notice the difference between how you flew, and how I did. From the moment I started the takeoff roll, until I hit FL300 I was paying attention to airspeed and adjusting the pitch to maintain the desired airspeed for the climb.

 

In your track the only time you were at the correct climb speed is when the aircraft happened to pass it while slowing down. Climb speed does not mean that speed or above, it means that speed and that speed alone. Climbing at anything other than best climb speed is less efficient, it doesn't matter if you're above of below.

 

As EtherealN said, as your AoA increases so does your drag. As you get slower there comes a point where the amount of drag exceeds the power output of your engines, and therefore the only way you can increase speed is to loose altitude. The key to the climb is never letting your speed get that low in the first place.

 

And when you are climbing at best climb speed, as soon as you can't maintain a climb without dropping below best speed, you have reached the effective combat ceiling for you current gross weight & drag index.

[159th_Viper]

The only reason you're running out of steam is that you're not flying the jet. As I said, you can't just set a pitch angle, open the throttle and expect the jet to climb all by itself with no further input.

 

 

No, it is not his fault.

 

Did you take control of his track at 18000' and attempt to climb further within the parameters you mentioned? I'm guessing not - do yourself a favour and try and you will realise that there is definitely something amiss. I'm guessing here but there seems to be a bork with the 'Game' Flight Mode/Model of sorts.

 

@ronvking - do yourself a favour and attempt the same flight in SIM mode and see the difference :)

[ronvking]

Thanks 159th_Viper, wilco re sim mode. Will try it now.

 

(Had been using game so I could get used to the aircraft and the systems)

[EtherealN]

Generally speaking, I'd advice to never use game mode unless you intend to stay there throughout the use of the product. Since behaviour in many facets will be different, you stand the risk of learning "wrong" and having to "unlearn" things when you go to Sim mode; and this is one thing intellectually, but since you want things to become sort of "muscle memory" it can be a hindrance to your development as a virtual pilot. (Think of it like learning to type on a QWERTY keyboard, and then suddenly switching to a DVORAK keyboard just as you got proficient with the QWERTY.)

 

That's my personal perspective though, this might obviously be different for each individual.

[159th_Viper]

Issue replicated in latest testers build and submitted to the internal Bug Tracker for rectification.

 

Ta for the report :)

[ronvking]

Yep, that was the "problem". Changed to Sim Mode and managed to get to 30000 without too much hassle.

 

As a check I levelled out at 18000 and max speed was 200kts and rising. Even at 30000 I managed more speed than in game mode at 18000.

 

Thanks to 159th Viper for the heads up and to the rest for the support and ideas.

 

Cheers Ron

[HammerUK9]

Just to give my tuppence worth:

 

I remember a mission on the 'introductory' campaign of DCS:BS that required you to pass over one of the mountain ranges to attack an encampment. When I first tried it, I flew nap-of-earth all the way in, but come the higher peaks of the range, ended up on the back of the performance curve and just couldn't climb/accelerate. After reading up on it, I then tried a gentle climb all the way from home plate - the result, sailing happily over the mountains without anything to worry about :)

 

Energy management is a big thing boys and girls!