A-10C Drag Index Chart

[lobo]

Wondering if anyone has more accurate info on the drag index for external stores on the A-10C... The values below are mainly from the A-10a manual. I've had to guess at some of these ie the AN-AAQ-28 Litening pod which I assigned the same drag index as an AGM-65. Anyone have more accurate info they can share?

 

Drag Index Chart

 

External Store (each) Drag Index

600 Gallon fuel tank 0.86

AN-AAQ-28 0.35

ALQ-131 0.75

LAU-68 (full) 0.27

LAU-68 (empty) 0.79

LAU-117 0.58

LAU-88 0.61

TER-9 0.61

Mk-82 0.20

Mk-82 0.25

Mk-82 AIR 0.26

Mk-84 0.50

CBU-87 1.17

CBU-97 1.17

LUU-2 0.45

GBU-10 0.71

GBU-12 0.51

GBU-38 0.20

GBU-31 0.50

CBU-103 1.17

CBU-105 1.17

AGM-65 0.35

AIM-9 (dual) 0.40

[Sierra99]

Unless the weapon is dramatically changed, the drag index should be the same...or am I missing something?

[Eddie]

I'll make corrections to what you've posted and fill in the gaps later on after work. A lot of the numbers you have are incorrect.

[Marklar]

Wondering if anyone has more accurate info on the drag index for external stores on the A-10C

 

Sorry for noob question, but what you need this information for? Is it somehow useful in our simulated world?

[Eddie]

It is just as useful in DCS as it is in the real world.

 

If you want to actually calculate your optimum cruise altitude you'll need to know your drag index, likewise if you want to work out your combat radius and/or work out bingo/joker fuel levels. The list goes on. Basically weight and drag are the two main things you need to know in order to work out performance data.

 

It's also a factor in deciding what weapon load to take on any given mission in the first place.

[Marklar]

I agree, if we are talking about long distance missions.

[Eddie]

It applies equally to all flights, irrespective of distance. However distance will have an impact on your selected cruise altitude in the case of a short transit to the contact point.

[Marklar]

OK, lets take a campaign mission for example. I've done only 10 missions so far. Every time I take 6x AGM65D, 2x GBU10, 2x AIM-9, TGP and 85% of fuel. In such configuration I am able to reach the target, destroy it, find and destroy extra targets market by JTAC, RTB and still have plenty of fuel on board. Why should I bother about optimum cruise altitude, combat radius and/or bingo/joker fuel levels?

Don't take me wrong. I am not saying all these drag/performance calculations are useless, just want to understand how and when virtual pilots use it in DCS world.

[Eddie]

Well that's because the campaign missions, and many community made missions have an insanely short flight time from homeplate to the target. Because I suspect many people would get bored having to fly for 15-20 (at least) mins to the target area.

 

Any mission made in a realistic manner, with the associated flight profile, especially where you need to maintain a station time would be very different. And if you were to fly CAS missions where station times are in play then in flight refuelling would come into play as well.

 

As an example, looking at my flying (all in MP) my shortest flight are usually in the 1.5-2 hour range. And some are 4 or more hours. And yes, that's without rearming. If it's a multi sortie flight with one of more rearming stops, it can be even longer. But obviously many people don't have time/can't be bothered flying in such a way, so the campaigns/missions included with the sim are very short to cater for the bulk of the player base.

[PhoenixBvo]

You'll find the procedure for range using drag index in section 4 of the T.O. 1A-10A-1-1 (the dash one) included in this pdf: A-10A Flight Manual. It starts on page 479 of that pdf. Thanks for uploading Eddie :)

[Eddie]

As for the OP. Drag Index values for the A-10C below.

 

BRU-42 TER: 0.74

LAU-117: 0.20

LAU-88: 0.50

DRA+2 LAU-105: 0.23

LAU-131/68: 0.80

SUU-25: 0.98

LITENING ATP: 1.17

MK-82/GBU-38: 0.14

MK-82AIR: 0.38

MK-84/GBU-31: 0.40

BDU-33: 0.02

CBU-87/97/103/105: 1.17

GBU-12: 0.51

GBU-10: 1.46

AIM-9M: 0.40

AGM-65: 0.82

ALQ-131(Deep): 1.18

MXU-648: 0.75

600 Gal Drop Tank: 1.45

[Marklar]

As I thought, long missions only :).

[PhoenixBvo]

As for the OP. Drag Index values for the A-10C below.

 

Thanks for posting! But could you explain the differences with the A-10A manual for the same items?

I mean, I know you have access to the correct info, but I don't really understand: e.g. the GBU-12 has drag index 0.51 in both tables whereas the GBU-10 has 1.46 in your list and 0.71 in the A-10A manual...

Edited December 3, 2012 by PhoenixBvo

[EtherealN]

As I thought, long missions only :).

 

To be precise, realistic missions only. :)

[Speedbrake]

Drag Index is a number calcualted at the (coef. of lift) CL=0.3 and a Mach of M0.8. It is adjusted by a some what standard set of curves for other CLs and Machs. It is a very good approximation of how and what the added drag of the store is on the aircraft. HOWEVER, there is also another term that needs to be taken into consideration, interferrence drag. This is the added drag due to the store(s) loaded on the adjacient store station.

[Eddie]

Thanks for posting! But could you explain the differences with the A-10A manual for the same items?

I mean, I know you have access to the correct info, but I don't really understand: e.g. the GBU-12 has drag index 0.51 in both tables whereas the GBU-10 has 1.46 in your list and 0.71 in the A-10A manual...

 

The A-10A manual you have is almost certainly from the 1980s, data such as this is updated quite often.

[lobo]

Thanks for the info Gentlemen! Much appreciated.

 

Cheers!

[lobo]

Sorry for noob question, but what you need this information for? Is it somehow useful in our simulated world?

 

Looking to do more realistic mission planning. Specifically fuel and bingo fuel calculations. :book:

 

With regards to Bingo, is it correct to say that bingo = climb (after combat) + cruise to base + reserve? Looking at the sample inflight data log in the 10A-1 manual (diagram A9-1)... in the example given in this diagram you would add 605 (climb) + 928 (cruise) + 2000 (reserve) for a bingo fuel of 3533 lbs? Is this correct?

 

Thanks

Edited December 3, 2012 by lobo**

[Eddie]

in the example given in this diagram you would add 605 (climb) + 928 (cruise) + 2000 (reserve) for a bingo fuel of 3533 lbs? Is this correct?

 

Thanks

 

Yep.

[lobo]

Yep.

 

Thanks Eddie. :thumbup:

[GripenNG]

It is just as useful in DCS as it is in the real world.

 

If you want to actually calculate your optimum cruise altitude you'll need to know your drag index, likewise if you want to work out your combat radius and/or work out bingo/joker fuel levels. The list goes on. Basically weight and drag are the two main things you need to know in order to work out performance data.

 

It's also a factor in deciding what weapon load to take on any given mission in the first place.

 

Hey Eddie, you have any availible diagrams for calculation of optimum cruise altitude? If not, how do I calculate it myself?

[Eddie]

Grab a copy of the A-10A -1, all the info for calculating such things is in there and still valid for the A-10C.

[PhoenixBvo]

Hey Eddie, you have any availible diagrams for calculation of optimum cruise altitude? If not, how do I calculate it myself?

 

http://forums.eagle.ru/showpost.php?p=1621017&postcount=10

[alfredo_laredo]

Grab a copy of the A-10A -1, all the info for calculating such things is in there and still valid for the A-10C.

 

Ok.. all charts on question have a max of drag index of 8.00

 

having 3 Mavericks on each wing add to almost 8.00.

 

And with a few bombs its very easy to get numbers up to 10-15 range.

 

Does that mean that any load above 8.0 its unrealistic?

[alfredo_laredo]

Anyone??