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Aircraft Total Weight


Zeke

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Is there a way to tell what the aircraft weighs at any given time or do you have to manually figure it out?

 

As far as I can tell you have to calculate that yourself. I imagine A-10 pilots calculating approach speeds during mission planning and probably performing a cursory check in actual flight.

 

A bit of Kentucky Windage to come up with a round figure I suppose...

 

effte; according to the manual, they're not allowed to rely on AOA indexer exclusively. It has to be the higher of either calculated speed or what AOA indexer tells them. Actual weight is therefore relevant.


Edited by chaos

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Thanks guys, I guess in order to figure out a good landing speed it will be a good idea to check fuel, and maybe subtract the weight of the stores you use in the mission. Nice pdf there too.

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In addition to my rather limited TOLD pdf, which only covers Nellis AFB, another user made a very nice mission planning program that I believe will give you basic TOLD data as well.

 

As mentioned here and elsewhere, the AoA indexer is a great tool, and indeed makes life easier. However, prior to approach the pilot is required to calculate a Final Turn Speed (used during the turn to final), an Approach Speed (used during straight-in final), and a Landing Speed (used at touchdown). The calculation is based on gross weight, and represents the minimum allowable speed for the approach.

 

These minimum speeds must be respected, even if the AoA indexer wants you to fly slower in order to get "on speed".

 

The computation is as follows:

 

The assumed configuration is gear down, full flaps, and speed brakes 40%. The aircraft gross weight is assumed to be 30,000 pounds.

 

The baseline approach speed is 130kt. Add 2kt for each 1,000 pounds over 30,000 pounds.

 

Add 15 knots to the calculated approach speed to determine the Final Turn speed.

 

Subtract 10 knots from the calulated approach speed to determine Landing Speed.

 

For example, at 35,000 pounds, the Final Turn Speed is 155kt, the Approach Speed is 140kt, and the Landing Speed is 130kt.

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...

 

Glad it works for you.

 

Since I got the sim, I always land the same way, wheter I'm heavy with payload or empty with 25% fuel:

 

Approach speed is 150-155kts, flight path indicator aimed at the start of the runway (all the time) untill I'm close enough (about to touch down) to start gently pulling it up to aim at the opposite end of the runway.

 

In the meantime I drop my speed to idle (right before landing) and just keep the FPI aimed at the opposite side untill my wheels touch the runway.

 

Not only I never had any problems with the above described method, I always manage to gently land the plane without "dropping" it.

 

I believe it's not so much about the landing speed as it is about the way you controll the touchdown ie. gently make the plane touch the runway.

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I believe it's not so much about the landing speed as it is about the way you controll the touchdown ie. gently make the plane touch the runway.

 

This is where you're 'wrong'. A 'soft' landing isn't always a 'good' one. Your aim should be to plant it in the designated spot _on-speed_. At 30.000lbs. you're going 25 kts too fast if you're flying @ 155kts. Your landing distance required will go up by a few hundred feet.

 

Now, the runway lenghts in DCS are not that critical but an anti-skid failure and landing a little long at too high of an approach speed will have you end up in the approach lights.... on the other end of the runway. "Oh Kenan... you've got some 'splaining too dooo...!! " :-)

 

 

PS; I haven't tried it yet but just fail the L-HYD sys. and try to land it at Batumi using your technique...


Edited by chaos

"It's not the years, honey. It's the mileage..."

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Just did a quick test... I compared landing distance at 30.000lbs. using the real A-10 procedures (TO-1A-A10) and the "Kenan" procedure (flying 25kts. too fast) _and_ switching of the anti-skid.

 

Odd outcome... I got more or less the same landing distance with either technique. Either my fLyinG skiLlz are not up to par or there's something funny going on with the ground-modeling... I'm going to 'investigate' further. Might open up a new topic in the appropriate forum.


Edited by chaos

"It's not the years, honey. It's the mileage..."

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Hi Chaos,

 

Before you post your results you may want to have a quick look at the first post here: http://forums.eagle.ru/showthread.php?t=66217

 

I thoroughly tested stopping distances in Beta 4 and found some strange results. Lighter aircraft took longer to stop from the same speed and the anti-skid made things worse.

 

A quick test of the initial release showed the A/S still increased stopping distances but I didn't recheck the other issues.

 

@BlueRidgeDx

Nice PDF! ....but did you check that increased weight really does increase stopping distance in game or is it just theoretical?

 

BiPod.


Edited by BiPod
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Just so you know, that's the real procedure in the real jet.

 

I'm sure it is. I'm just saying my way works fine as well. I'm gonna post a track little later to show you my landing techniques both all loaded up and 20% fuel weight empty.

 

I never get the big "bump" upon landing ie. I never get the feeling that I slammed into the runway as always keeping the FPI at the opposite end of the runway ensures my angle of attack (or whatever it's called) is not too steep.

 

But, anyway, instead of just trying to describe you what I'm doing, there will be track (or video) soon posted and you will see my landings are just as fine.

 

So, it's either simulator being not so detailed (if I'm really doing it "wrong") or it's in the boundaries of acceptable landing parameters.

[sIGPIC][/sIGPIC]

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2nd Company 1st financial guard battalion "Mrcine"

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Or, the third explanation:

 

Few knots extra won't make much of a difference to the A10 landing gear (ie. it's not made out of paper).

 

I'm not saying one should slam to the runway as long as the gears can hold up but small difference in speed shouldn't be much of an issue.

[sIGPIC][/sIGPIC]

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But, anyway, instead of just trying to describe you what I'm doing, there will be track (or video) soon posted and you will see my landings are just as fine.

 

I'm looking forward to commenting on it ;)

"It's not the years, honey. It's the mileage..."

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Or, the third explanation:

 

Few knots extra won't make much of a difference to the A10 landing gear (ie. it's not made out of paper).

 

I'm not saying one should slam to the runway as long as the gears can hold up but small difference in speed shouldn't be much of an issue.

 

I think we're not talking about the same thing here... It has nothing to do with how soft or hard the landing is. I believe certification allows descent-rates in excess of 600fpm but that's not what we're talking about. It's the amount of runway you chew up by landing fast (ie. forward speed... not vertical).

"It's not the years, honey. It's the mileage..."

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My Firefox4 just crashed and my upload failed. Since I don't plan on waiting another 40 mins, here are the parameters of my landings:

 

1. 25% of fuel, no payload, light as a feather, aproach speed 150-155 knts, touchdown at app. 119 kts.

 

2. 100% fuel, full payload, heavy as a pig, aproach speed 150-155 kts, touchdown at app. 143 kts.

 

Landed gently, didn't damage my gear and didn't run out of runway.

Although it works for me, I don't want to be missunderstood: I'm not saying my way of landing is "the bestest" just trying to show it works as well.

[sIGPIC][/sIGPIC]

Commanding Officer of:

2nd Company 1st financial guard battalion "Mrcine"

See our squads here and our

.

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1. 25% of fuel, no payload, light as a feather, aproach speed 150-155 knts, touchdown at app. 119 kts.

 

The issue is the runway you are eating up as you are decelerating from 150 knots to 119 knots. The best way to increase the runway required to come to a stop is to nudge the speed over the threshold up a bit. Chews up runway meters like there is no tomorrow... or at least no far end of the runway.

 

"But I have plenty of runway"?

 

Yes. But if you had the right speed over the threshold, you'd have more of a margin for low surface friction, brake failures etc. You'd come to a stop sooner, enabling an earlier turnoff and more efficient use of the runway. You'd be at a lower speed as you descend into bird-strike territory. You'd be able to coast to a stop and save break and tyre wear.

 

Gusting/windy conditions is about the only time carrying excess speed can be tolerated - if there is runway to spare.

 

 

While I'm writing I'd like to say thanks to those pointing out that you should always mind your calculated speeds as well as the indexer. That was me sim-simplifying real-world procedures.

 

Cheers,

Fred

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Rule of Thumb - you want to be at 50' AGL as you cross (fly over) the Runway Threshold while simultaneously bringing the throttles to idle.

 

By 5 miles out from the runway you should be on speed (Vref), and fully configured for a stable approach. Carrying extra speed will result in significantly more runway used.

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