Jump to content

F-16 Excessive AoA in level flight


Exorcet

Recommended Posts

With the new flight model changes the F-16 seems to have become more responsive, but the AoA required for level flight has increased. It's especially obvious with two external tanks.

Pre patch single tank loadouts at altitude would sit around 3-4 degrees AoA, now even an AA loadout can exceed 5 degrees. Two tank loads can approach 7 and are far too draggy for the F-16 to maintain speed.

Is this expected behavior, or is the FM in need of more tuning?

F-162tank24k.trk

  • Like 4
  • Thanks 1

Awaiting: DCS F-15C

Win 10 i5-9600KF 4.6 GHz 64 GB RAM RTX2080Ti 11GB -- Win 7 64 i5-6600K 3.6 GHz 32 GB RAM GTX970 4GB -- A-10C, F-5E, Su-27, F-15C, F-14B, F-16C missions in User Files

 

Link to comment
Share on other sites

  • ED Team

Hi, 

this is correct as is, if you have any unclassified information suggesting it is not please let us know. 

thank you

smallCATPILOT.PNG.04bbece1b27ff1b2c193b174ec410fc0.PNG

Forum rules - DCS Crashing? Try this first - Cleanup and Repair - Discord BIGNEWY#8703 - Youtube - Patch Status

Windows 11, NVIDIA MSI RTX 3090, Intel® i9-10900K 3.70GHz, 5.30GHz Turbo, Corsair Hydro Series H150i Pro, 64GB DDR @3200, ASUS ROG Strix Z490-F Gaming, HP Reverb G2

Link to comment
Share on other sites

I posted some test results from earlier in another thread, may do good here. All using wing tanks and little over half load of fuel. Threw on burner to get to around .88 to .9 mach then into mil power and left it. Alt Hold at 25k or 30k ft depending on the test and just fast forwarded the mission until speed steadied. Read left to right...Altitude, mach speed ag ordinance T2 (Wing tanks) (all pods except for A2A config with wing tanks test) aa ordinance 2 aim 120c's and 2 9x's and fuel flow in pounds per hour 

image.png

  • Like 4
Link to comment
Share on other sites

It cannot be correct as is today, a viper can accelerate better than hornet with same loadout and climb higher...

And for sure keep M.9ish with 2 tanks and air to air config above FL300, which is not the case today.

I guess once they adjust the FM we will have the CRUS page...


Edited by Spartan111sqn
  • Like 1
Link to comment
Share on other sites

If you load the Viper like a bomb truck, it won't cruise well. 4 JSOWs aren't very common for a good reason, and that reason is, they really weigh the poor Viper down. It's a small, lightweight fighter, and in a fighter configuration, it can cruise at 30kft no sweat. Strap a B-17 level bombload to it, and it'll fly like a B-17... one with a wing way too small for its weight. If you need to carry that sort of load, fly lower. This matches both the manual and the other sim. Just give it more throttle, why do you think the Viper has the reputation for being thirsty?

CFTs aren't as bad for the drag as air to ground loads, not to mention you don't need 600 gal bags when you have CFTs. This, however, is the reason why US doesn't use CFTs. AAR doesn't weigh down the poor Viper nearly as much as extra fuel does.

Link to comment
Share on other sites

4 hours ago, Spartan111sqn said:

It cannot be correct as is today, a viper can accelerate better than hornet with same loadout and climb higher...

 

Hey, Spartan. I just did a quick little test with both jets loaded with 80% internal fuel, 2 wingtip 9X's, three drop tanks, and no other pylons or pods. At 16K msl, both jets starting at 400kts and going full burner immediately at mission start, the Viper beat the Hornet to Mach 1.0 by about 4 seconds (it took the Hornet 34 sec and the Viper 30). Air temp was whatever the default one is on the Caucasus map.

Happy to attach the mission if you'd like or you can run some more extensive ones yourself. 👍


Edited by wilbur81
  • Like 1

i7 8700K @ Stock - Win10 64 - 32 RAM - RTX 3080 12gb OC - 55 inch 4k Display

 

 

Link to comment
Share on other sites

23 minutes ago, Dragon1-1 said:

If you load the Viper like a bomb truck, it won't cruise well. 4 JSOWs aren't very common for a good reason, and that reason is, they really weigh the poor Viper down. It's a small, lightweight fighter, and in a fighter configuration, it can cruise at 30kft no sweat. Strap a B-17 level bombload to it, and it'll fly like a B-17... one with a wing way too small for its weight. If you need to carry that sort of load, fly lower. This matches both the manual and the other sim. Just give it more throttle, why do you think the Viper has the reputation for being thirsty?

CFTs aren't as bad for the drag as air to ground loads, not to mention you don't need 600 gal bags when you have CFTs. This, however, is the reason why US doesn't use CFTs. AAR doesn't weigh down the poor Viper nearly as much as extra fuel does.

Israel sure seems to like using 600 gallon bags with CFT's. Regardless, a normal sead load of 2x harm, 2x 370gal, and a jammer even has a hard time cruising at anything above 20k feet. Is that a bomb truck as well?

Link to comment
Share on other sites

It's not, you just have to go reasonably fast, about 300kts should be fine. The Viper doesn't like being too high, try cruising at about 25k. Remember that in warm air AoA will be higher, so it'll also depend on the weather. Most of all, handle it gently, don't expect behavior that you get in a dogfight at 400kts or so. Hornet is easier to handle in high altitude cruise because it has a big, straight wing. It pays the price in other areas, though.

Link to comment
Share on other sites

vor 8 Stunden schrieb Carbon715:

Supports the high alpha mil power cruise loaded with wingtanks?

Support the turn rates, speeds, fuel flows and sustainable MIL power speeds which depends directly on AOA and lift. If there are numbers proving otherwise, I would be interested as well.

vor 6 Stunden schrieb Crptalk:

Israel sure seems to like using 600 gallon bags with CFT's. Regardless, a normal sead load of 2x harm, 2x 370gal, and a jammer even has a hard time cruising at anything above 20k feet. Is that a bomb truck as well?

I cruise with that loadout quite regularly, even with a TGP and HTS. You need to maintain a speed of about Mach 0.7 to Mach 0.8 to minimize the sum of induced drag and parasite drag. This is also the most fuel efficient area at altitude. 

If you get slower, the induced drag of the high AOA will be a large factor, slowing you down until you fall out of the sky.

Link to comment
Share on other sites

14 hours ago, wilbur81 said:

Hey, Spartan. I just did a quick little test with both jets loaded with 80% internal fuel, 2 wingtip 9X's, three drop tanks, and no other pylons or pods. At 16K msl, both jets starting at 400kts and going full burner immediately at mission start, the Viper beat the Hornet to Mach 1.0 by about 4 seconds (it took the Hornet 34 sec and the Viper 30). Air temp was whatever the default one is on the Caucasus map.

Happy to attach the mission if you'd like or you can run some more extensive ones yourself. 👍

 

cool @wilbur81, but I mean in MIL power, in full burner Viper is a beast, but MIL power is far from RL, as a comparison, MIL in buster should be like hornet in medium burner with same loadout.

Link to comment
Share on other sites

Yeah, that's what I'm gathering too.   I'm away at ground school learning a new jet, but i ran some of the cruise charts yesterday for a few loadouts i commonly use, and the numbers matched what i remember from the new flight model.  I'll do some flight tests when I get home, but I'm excited about how it's looking. 

Dances, PhD

Jet Hobo

https://v65th.wordpress.com/

Link to comment
Share on other sites

vor 2 Stunden schrieb Spartan111sqn:

Really matching the charts?  That speed is not operative, is even below optimum speed for cruise...

Optimum speed is the one with the slowest total drag in that case. A high drag index shifts the optimum speed to the slower. It might be possible with Mach 0.8 though. Just not with 0.95 or 0.5. Need to dig up the charts.

I can calculate it some time at the weekend, just now I am flying 😁

Ah wait I don't have a drag index for the HTS and ALQ-131... Might add a drag index display to the wishlist 

  • Like 1
Link to comment
Share on other sites

On 3/18/2022 at 9:07 PM, Exorcet said:

With the new flight model changes the F-16 seems to have become more responsive, but the AoA required for level flight has increased. It's especially obvious with two external tanks.

Pre patch single tank loadouts at altitude would sit around 3-4 degrees AoA, now even an AA loadout can exceed 5 degrees. Two tank loads can approach 7 and are far too draggy for the F-16 to maintain speed.

Is this expected behavior, or is the FM in need of more tuning?

F-162tank24k.trk 28.61 kB · 4 downloads

I have flown the Lockheed Martin Viper Simulator setupe'd with 2 external fuel tanks . I don't remember 7 degrees AOA level flight in any speed range especially in the low range.  Personally, I think the whole  DCS FM  handling is very different in a weird way. BMS FM approach  is more preferable to me but still doesn't  quite hit the spot,  it's  stick feedback  is also rather  vague. On the other hand, these are  the best and only Viper  representations available to consumers we have. For this reason, I am gratefull and my criticism is aimed in a constructive manner.

  • Like 4

Obsessed with FM's

Link to comment
Share on other sites

After reviewing it looks like the flight model is not as far off in cruise as I thought it might be, however it might still be slightly underperforming. I will continue to look into it to make sure I'm not making any mistakes. The F-16 being such a light fighter means it will struggle with heavy payloads and it seems like the wing tanks really produce a large amount of drag (speaking of which it would help if DCS listed drag indexes).

  • Like 1

Awaiting: DCS F-15C

Win 10 i5-9600KF 4.6 GHz 64 GB RAM RTX2080Ti 11GB -- Win 7 64 i5-6600K 3.6 GHz 32 GB RAM GTX970 4GB -- A-10C, F-5E, Su-27, F-15C, F-14B, F-16C missions in User Files

 

Link to comment
Share on other sites

Right, we don't have drag indexes for ECM pod, litening pod, or HTS pod. We might be able to get that from the other sim, but who knows where they got it from.

Running the charts for optimum mach is the key, then figuring out where you want to cruise, and what kind of fuel flow you should expect at that altitude for that mach number. Can't wait to get home to test it.

Sent from my Pixel 3 XL using Tapatalk

  • Like 1

Dances, PhD

Jet Hobo

https://v65th.wordpress.com/

Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...