Drag Indexes & Weight info for each store and pylon for performance calculations & flight planning

[Lau]

Good Day,

Is there a way to get the Drag Indexes, Weights for each store and pylon in order to conduct performances and flight planning calculations ?

For the weights, I have done some work extracting data from the loadout window from the ME, however the results I am getting are strange since the zero fuel weight is calculated with external pylons. It is possible to find the weight of these external pylons by removing them even if that makes the zero fuel weight move to negative values which is a weird way of calculating weights since we are not in space 

The reason I am asking this informations is because I believe there is a mistake on the final figure that has been retained on the zero fuel weight and that this mistake could be linked to the reason that these external pylons could have been added two times.

Thanks,

 

pylon i/o weapon

Edited October 30, 2024 by Lau

[3000 Black Jets of Allah]

Try looking for the TO 1F-4E-1 manual, it has a section for DI and weights etc. for all pylon and store setups. I've done some calculations with those values and the performance charts and it's pretty spot on

[Lau]

On 11/2/2024 at 5:55 PM, 3000 Black Jets of Allah said:

Try looking for the TO 1F-4E-1 manual, it has a section for DI and weights etc. for all pylon and store setups. I've done some calculations with those values and the performance charts and it's pretty spot on

Hey, just noticed your reply was not expecting one anymore, so good to read that at least one other person is considering weights and drag indexes while performing flight planning in DCS with the HB F4E. I also used the real F4E manual and found some discrepancies so it will be interesting to compare my results with yours and also talk about how you are using drag calculations within your flight planning.

I will come back to you in the near future on this topic to see if we can find an accurate and reliable way to use the information at hand for accurate flight planning within DCS.

Could you please in the future "quote" the message you are raplying to or use @username to make sure we do not miss your replies. On the other hand, I am as guilty as you since I do not have the habit to follow my own threads.

Thanks a lot,

 

Edited November 7, 2024 by Lau
small typo

[Lau]

@3000 Black Jets of Allah

It would be nice if we can work on an example just to figure out if we can get to the same numbers that worked for you.

- What payload configuration Weights & Drag Indexes did you use during your test flight ?

- What performances did you calculate (t/o, clb, crz, descent, landing) ?

- What result did you get while flying in the simulator ? Spot on seems too good to me since the numbers are not exactly the same from the manual to the sim, so just curious.

I would like to then test your numbers in the simulator to see if I can get to the same result.

Considering that HB is doing its best to be as close as possible to the numbers in the manual, my initial question was trying to find a way to get the actual numbers simulated in the sim, to avoid the discrepancy in between the manual and the sim. It is also not easy to ID all the weapons and pylons between the manual and the sim since they do not use the exact same names. I found that weights are not exactly the same either sim vs manual.

I have gathered the best way I could all the weights and drag indexes and my next steps is to actually test them in the sim, this is why I would like to work on examples of calculations with you, so we can then test them in the sim to see how reliable and accurate these numbers are.

My guess would be that if the numbers from the sim and the manual are different, that the game does not exactly simulate the testing environment of the real aircraft, we are bound to some discrepancies. "Spot on" seems therefore a bit excessive considering so many variables.

This is the reason I would like to work directly from the numbers in the sim as opposed to those from the real airplane. It would be very nice if HB could provide us with this data.

That being said if HB did manage to get spot on to the real plane numbers, then I would be more than glad to use the data from the real manual page 255.

Thanks,

[Zabuzard]

The weights are all defined in the main lua file in your game folder. Something like Dcs/Mods/aircraft/F-4E/Entry/F-4E.lua and the Weapons.lua right next to it.
You can probably CTRL+F "weigth" or "drag" your way through it
Any weapon not defined in those files is DCS-built-in and defined by ED.

[Lau]

Awesome thanks

[Volator]

Got a question concerning the weight drag index calculation:

How do you deal with the various configurations given for the inboard pylons in the Dash-1?

There are weights and drag per station given for

• inboard armament pylon, 264 lb / 2.6 
• inboard armament pylon and TER, 359 lb / 6.8
• inboard armament pylon and two Aero-3B missile launchers, 403 lb / 3.4
• [...]
• inboard armament pylon and two ALE-40 dispensers, 309 lb / 5.4

But what do I do if I have an inboard armament pylon + TER + two Aero-3B missile launchers + two ALE-40 dispensers? Which weight and drag should I take for the calculations? Simply adding them can't be correct. Do I have to calculate the differences from the basic inboard armament pylon and add those to the basic numbers? If that's the case, why in the world couldn't MDD just provide the differences directly (like "add 55 lb / 0.4 for each Aero 3B missile launcher")?!

[Lau]

Hi @Volator

When I calculate Drag & Weight I am only looking for the big picture to enter the perf charts for some initial flight planning. Flying by the numbers is not always possible unless on a dedicated training flight and on a day close to standard athmosphere albeit a virtual one. This will already give you some discrepancies from your initial calculations. Also the numbers used by HB are not exactly the same but very close to the FM perf and then DCS has its interpretation of Drag through formulas. 

With the above in mind here is a sample for a SEAD config giving a total Weight of little over 54k lbs and 67 DI (I did not include the ALE-40, should have…).

With regards to the ALE-40 if not carrying AIM, add the ALE-40 DI and with AIM on the AERO3B, I would use the AIM DI + 1.4 DI for the ALE-40 since it is protruding a little more than the AIM.

From flight to flight your numbers will become more accurate as you narrow the actual SIM performance numbers.

Best,

Lau

 

Edited January 8 by Lau