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Excessive drag on glove pylons


captain_dalan

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Did some speed runs in the free flight missions today. Dropped the tanks but kept the Winders and the Sparrows on the glove pylons. Climbed to 20000ft, accelerated to mach 0.9 then climbed to 37000ft, leveled off and plugged in full burner. The plane can't push past the mach 1.0 number. I fire the missiles and look and behold, the plane accelerates to mach 1.9 in a climb to 40000ft (didn't bother to trim). Worked around the engine fire issue by throttling down a few seconds for the temperature to subside.

Got another bird, this time i mounted 4 Sparrows in the funnel and clean wing glove pylons. Same procedure. This time the plane is stuck at mach 1.2 at 37000ft. I fire the missiles and the plane starts accelerating again. So both stations seams to suffer from excessive drag, but the wing glove pylons more so. Or is it the stores? As in the Winders slowing the plane more then the Sparrows?

This is all in an F-14A BTW.

Modules: FC3, Mirage 2000C, Harrier AV-8B NA, F-5, AJS-37 Viggen, F-14B, F-14A, Combined Arms, F/A-18C, F-16C, MiG-19P, F-86, MiG-15, FW-190A, Spitfire Mk IX, UH-1 Huey, Su-25, P-51PD, Caucasus map, Nevada map, Persian Gulf map, Marianas map, Syria Map, Super Carrier, Sinai map, Mosquito, P-51, AH-64 Apache

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Well AIM-9s on station 1A, 8A have drag index 8 (per station), AIM-7s in tunnel have drag index of 2 (per station), so you have twice the drag index carrying 2*9s over 4*7s in tunnel. But even still, I too find the stores drag to be excessive.

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While glove AIM-9s have a higher DI than fuselage AIM-7s (it got recalculated to 5,5 from 8,8 in the 80s), they won't affect the aircraft to that degree.  The F-14A's MaxQ in level flight with a 4x4 loadout (AIM-9 on 1A, 1B, 8A, 8B and 4x fuselage AIM-7s) is 2.15M at 37,000 feet, so if there is a drag problem, it sounds exponentially off.  Last night I was online with a 2x2x4 and was able to accelerate to 1.1M before temp spiking and cutting the cans, so I could pass Mach 1, and would have gotten faster were it not for the TF-30s trying to disassemble themselves.  This was at ~24,000 feet.

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This is a problem with many more stores and even planes. Try the rocket launchers and TALD for example and your Tomcat gets overtaken by a Warthog. Or try the Hornet with Sparrows on the wing pylons. Even after shooting them off, the thing can't even reach M 1.0. This is something ED has to fix globally, especially since only they have control over the rack drag and as of recently, the weapons and stores.

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On 1/17/2021 at 5:32 PM, Eldur said:

This is a problem with many more stores and even planes. Try the rocket launchers and TALD for example and your Tomcat gets overtaken by a Warthog. Or try the Hornet with Sparrows on the wing pylons. Even after shooting them off, the thing can't even reach M 1.0. This is something ED has to fix globally, especially since only they have control over the rack drag and as of recently, the weapons and stores.

C*rap...... and some thought that would be a good idea......
I mean, this is laughable level of performance, and it clearly isn't the plane or the engines. I've never tested her with irons or rockets, as usually do A-A or joyriding, but if what you say is true........  😞

Modules: FC3, Mirage 2000C, Harrier AV-8B NA, F-5, AJS-37 Viggen, F-14B, F-14A, Combined Arms, F/A-18C, F-16C, MiG-19P, F-86, MiG-15, FW-190A, Spitfire Mk IX, UH-1 Huey, Su-25, P-51PD, Caucasus map, Nevada map, Persian Gulf map, Marianas map, Syria Map, Super Carrier, Sinai map, Mosquito, P-51, AH-64 Apache

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Then the next time i have enough free time to fly i should try and cover more possible loads. A few come to mind:
-2 Sparrows in the funnel VS 2 on the wing pylons
-4 Winders on the pylons VS 2 Winders and 2 Sparrows on the pylons
-2 Winders VS 2 Sparrows all on the pylons....

Modules: FC3, Mirage 2000C, Harrier AV-8B NA, F-5, AJS-37 Viggen, F-14B, F-14A, Combined Arms, F/A-18C, F-16C, MiG-19P, F-86, MiG-15, FW-190A, Spitfire Mk IX, UH-1 Huey, Su-25, P-51PD, Caucasus map, Nevada map, Persian Gulf map, Marianas map, Syria Map, Super Carrier, Sinai map, Mosquito, P-51, AH-64 Apache

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What happened to Draconus' post?

Modules: FC3, Mirage 2000C, Harrier AV-8B NA, F-5, AJS-37 Viggen, F-14B, F-14A, Combined Arms, F/A-18C, F-16C, MiG-19P, F-86, MiG-15, FW-190A, Spitfire Mk IX, UH-1 Huey, Su-25, P-51PD, Caucasus map, Nevada map, Persian Gulf map, Marianas map, Syria Map, Super Carrier, Sinai map, Mosquito, P-51, AH-64 Apache

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9 minutes ago, captain_dalan said:

What happened to Draconus' post?

I've hidden it because after my search I'm no longer sure how it is implemented in DCS. There were also some older test done which have shown differences in drag depending on the store placement.

 


Edited by draconus

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awkward

On 1/20/2021 at 11:34 AM, draconus said:

I've hidden it because after my search I'm no longer sure how it is implemented in DCS. There were also some older test done which have shown differences in drag depending on the store placement.

 

 

Ah, roger that. Decided to continue with the tests tonight, but something really strange happened, something i did not expect. At all....

Like, i started with some warmup flights, designed purely to train my muscle memory. Nothing fancy, just a couple of birds, one completely clean, the other with the usual 4x4 stores configuration. Maintaining level turns at 0ft, 5000ft, 10000f at 350KIAS. Didn't actually plan to taking any measures, i something caught my eye. My turns were at 350 knots, and i noticed the difference in sustained g was very small. Almost too small in fact. When i repeated the flights with more care, it turns out the difference in performance was only about 5-5.5%. Which is exactly what the difference in gross weight is. As if the drag isn't taken into account? Which is weird, as we know the stores do cause transonic acceleration issues.

Could it be that the F-14 ALWAYS flies with at least some stores drag? Even when empty? I'm assuming something like this, because the figures with 4x4 are pretty close. Only 0.3g off. So if i have 5.1-5.2 g at 350KIAS, ASL, i would expect to have more then 5.4-5.5 in a sleek plane....... awkward ...

Modules: FC3, Mirage 2000C, Harrier AV-8B NA, F-5, AJS-37 Viggen, F-14B, F-14A, Combined Arms, F/A-18C, F-16C, MiG-19P, F-86, MiG-15, FW-190A, Spitfire Mk IX, UH-1 Huey, Su-25, P-51PD, Caucasus map, Nevada map, Persian Gulf map, Marianas map, Syria Map, Super Carrier, Sinai map, Mosquito, P-51, AH-64 Apache

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