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I think it is avionics stuff and the like.. The middle of the aircraft is full of pegasus engine, so the avionics are stuffed in front and rear avionics spaces...

Yes, until the last 20 feet when you can use power to control ROD at touchdown

I think we need to understand which variant of engine the manuals are related to. The older engines (and possibly older manuals) would be for the lower thrust engine (-106 I believe?). For this engine, R80 would equate to around R90 in the DCS model engine (which is the later variant and for which thrust levels need about another 10% RPM at mid RPM levels; Yes, with R80 in the previous engine, it would need N60 or above. The VNSL was typically flown with R75 in the smaller engine, which needed around 50N for a stable approach. The nose heavy tendency of the TAV8B has little to no impact on VNSL, since the fwd CofG becomes an issue in low speed VSTOL manoeuvers which rely more heavily on the front puffer for pitch authority. This is a healthy debate, and it would be good if we could get to the bottom of the data and how we can get the model to better match RL. At the moment, it is quite a bit off (IMO) in thrust/drag modelling which is a real shame given it is such a good replication of the AV8B.

The 40N at the end of downwind is a suggested N angle to get the speed under control. It is not to do with flap/nozzle impingement, which can occur only in STOL flap and after a dual channel flap controller failure, since both Flap 1 and 2 channels will automatically schedule the flaps as the nozzles travel beyond approx 30 deg. For example, at 40N the flap will be around 47F. I stand by my comments regarding the thrust/drag model in DCS vs RL. It is a shame the model (which is otherwise good) is not as good as it could be in this regard, leading to some unusual RPM fiigures vs speeds or RPM vs N for VNSLs. 85% for an AUTO flap VNSL should yield N angles in the 45-60N range for a controlled approach at low aircraft weights.

including the expected nozzle angles?

Yes, they can be achieved in game, but it is more difficult since the thrust/drag models are not that accurate vs RL, and the manuals quote RL power settings.

LIDS only has an effect when the aircraft enters ground effect. It creates the last side of a 'box' comprising airbrake, gun pods (or strakes) and then the LIDS. It captures the rebounding jet exhaust to help cushion the landing. That said, in headwinds much over 20kts, it doesn't do much since the jet cushion is blown backwards and the 'box' area less effective

paradoxically, a more accurate thrust/drag model would make it easier to fly. But I echo your comments; it is a good 'beta' representation of the VSTOL flight model. The aircraft for real is demanding to fly in the VSTOL environment. In fact, without the feedback you get in RW (acceleration forces, great visuals and peripheral) some manoeuvers in simulation are more difficult than for real! Particularly true for VLs and AAR.

Just done some experimentation. On the ground, 33% 10N keeps a steady taxy speed in the teens. Normally, idle and 50N is required to control speed on the ground, since the aircraft dashes off like a scalded cat at idle & 10N. This indicates a ground friction model which is too high. In the air, with a clean aircraft and around 4.5k fuel and water, 39% maintains 230 kts and 41% 300 kts. That suggests that idle plus 12% can overcome 300kts worth of airborne drag. This suggests that either the RPM vs thrust model gives too high a thrust in the air, and/or the drag model is set too low. I'd suspect the latter is definitely involved somehow (if not a bit of both), since the flight model is very reluctant to lose speed, and the AV8B is very draggy compared with 'normal' jets. All that VSTOL gubbins has a big drag penalty! For example, in the smaller engined version (and RPM tended to be about 10% lower for the same thrust as the big engine), around 60% is a good figure to hold 230 kts.

another thumbs up for delanclip and PS3. Works really well for me. Never had a TrackIR but I couldn't justify the $$$ for one.

I can but try! It is a shame the thrust/drag model is quite so far off, because otherwise the FM makes a really good stab at replicating AV8B behavior.

I apologise, I think I used the export designations for the engine, I should have used the US desigs instead. the 108 is equiv to the 408 etc, the 105 was the smaller engine... You're right, airfield altitude will make a difference (and so will ac weight), but the fact that 80% (the lowest of the RPM quoted) requires very high nozzle angles for the VNSL points at the model being over-powered or 'under-dragged'. The same can be said for its conventional level flight characteristics - it just goes too fast for its RPM (and very reluctant to slow down - it is a very draggy jet in RL - which may be a drag modelling issue).

the FM is not too bad at all, except for the big proviso of the issue of too low a drag value and possibly too high a thrust level at moderate RPMs. The response in ground effect could be modelled with simple algorithms to reduce engine power if you sit in a very low hover (sub 30 ft) to mimic hot gas ingestion. However, if you practise / mimic the correct VSTOL techniques, then you should rarely, if ever, need this element of a FM, since the techniques are designed so that you don't loiter in the height band where significant ground effect / reingestion become an issue. I'm all for improving the FM though!

there's not a massive difference I don't think between the 2 ac for VNSLs. The twin sticker is a bit heavier (about 2000 lbs) so would be just like a single seater carrying a bit more fuel. For the -105 engine, the typical power used would be 75% at low fuel weights, for the -108 (which we have in the model) it is 10% higher - it isn't developing more thrust at 85% than the -105s 75%, it is just the thrust vs RPM relationship is different. 80 - 95% is the range of RPM recommended; going towards the upper end if heavy, hot and high.. For practise at typical pattern training fuel weights (circa 4k lbs and below), 85% is the norm since it is a good compromise and makes the pattern repeatable. If you set a different power every time, it would be really hard to master when learning! (I guess same goes for learning the the DCS flight model too!).

Altitude reduces the engine performance so technically, you'd have to use less nozzle angle to maintain AOA for a given aircraft weight. So taking your experience at height, you'd need more nozzle angle lower down for the same RPM. (Stupid question (sorry), you've got the RPM switch in LOW? lower left console at the back). I still believe that the thrust and/or drag FM for this early access version is not quite right yet - too much thrust for RPM, or too little drag, or a combo of both. If you set much lower RPM (in this flight model) than the manuals suggest, you get a more realistic VNSL approach.