[Investigating] DCS AV-8B STR test

[Hummingbird]

AV-8B
20,941 lbs, 6x pylons,  4x AIM9's, full guns, @ Sea level / ICAO std. day 15 C

STR DCS vs RL
M 0.4 = 4.10 G vs 3.20 G (+1.90 G off)
M 0.5 = 5.45 G vs  3.60 G (+1.85 G off)
M 0.6 = 6.65 G vs  3.95 G (+2.70G off)
M 0.7 = 6.05 G vs 3.90 G (+2.15 G off)
M 0.8 = 3.8 G vs 0 G (+3.8 G off, real aircraft can't even attain said speed in level flight at SL)

ITR DCS vs RL
M 0.65 = 9.0 G vs 7.8 G (+1.2 G off)

 

Spoiler

 

Guys, this is not so good, it's way off the charts 

 

Reference: NAVAIR 00-110AV8-4, cleared for open publication.

 

Edited October 26, 2021 by Hummingbird

[Wisky]

those graphs are for the old engine

the harrier has received an engine upgrade between 2000-2010 giving 15% more thrust. So your cleared for open publication document is not even worth the paper it was printed on and certainly cant be used to compare with our current (~2015ish) Harrier in DCS

[TLTeo]

To be fair, that would be true for STR, but ITR doesn't really care about engine trust, so something is likely still off. And a new engine seems unlikely to give you ~30-50% STR. I've been critical of Hummingbird's posts for other aircraft because those differences were really tiny, but in this case the discrepancies are anything but that.

[Wisky]

6 hours ago, TLTeo said:

To be fair, that would be true for STR, but ITR doesn't really care about engine trust, so something is likely still off. And a new engine seems unlikely to give you ~30-50% STR. I've been critical of Hummingbird's posts for other aircraft because those differences were really tiny, but in this case the discrepancies are anything but that.

yes ITR doesnt care about that. But you dont know what kind of tweaks have been done to increase turn rate over the years. It is very likely that new stuff has been added or exchanged to allow for better turn rates. I mean we are talking a 40 year old publication here

[Bremspropeller]

The only aerodynamic changes I could think of are the different LERX versions. In game, we do have the full-size/ large ones.

[TLTeo]

No aerodynamic tweak is magically going to increase ITR by that much either.

[Bremspropeller]

I would not underestimate the difference in performance, the bigger LERX are providong.

[AlphaJuliet]

Interesting. I'll take a look around to see if this data is valid for our DCS module.
I'll contact the flight model team to see what they think about it.

[Hummingbird]

7 minutes ago, AlphaJuliet said:

Interesting. I'll take a look around to see if this data is valid for our DCS module.
I'll contact the flight model team to see what they think about it.

 

Thank you.

 

 

 

[Hummingbird]

15 hours ago, Wisky said:

those graphs are for the old engine

the harrier has received an engine upgrade between 2000-2010 giving 15% more thrust. So your cleared for open publication document is not even worth the paper it was printed on and certainly cant be used to compare with our current (~2015ish) Harrier in DCS

 

Sorry but a 15% increase in thrust in no way justifies at 68% increase in STR performance.

Currently the AV-8B is outperforming every single other 4th gen fighter in DCS (plenty of which feature more extensive LERX, LEFs, TEFs and much more favourable lift/drag & thrust numbers) when it comes to STR from M 0.6 and below. If that doesn't set the alarm bells ringing, , then I don't know what will... 

[Hummingbird]

After some more testing I can say it for sure has to do with incorrect drag values, as the vertical climb rate of the aircraft is not very impressive... infact it's the opposite considering the thrust to weight ratio of the thing.

All very odd, I remember the FM seeming quite authentic about a year ago.

Edited October 28, 2021 by Hummingbird

[AlphaJuliet]

A lot of changes were made to the module, adjusting other areas of the FM made the EM perfs drift towards what we have today.
The FM team acknowledged that now is the right time to take a look at this area of the FM. 
We will get into a feedback loop of testing and adjusting with the SMEs and regarding what available data we have.

It may not be perfectly accurate to the curves you cited though, as they do not represent the performances of our Harrier version. Our N/A is more aerodynamically refined, more powerful but also more heavy than the early Day Attack from which the quoted curves are coming from.

The aircraft should however get less efficient in turns than it is now.

Cheers,

Alpha