Goggles

According to the SA-341G flight manual, the SAS does (yes) have a SAS yaw channel. However, it disengages when the airspeed exceeds 90 km/hr. The autopilot itself does not (no) have a yaw channel. According to the flight manual, the autopilot is separate from the SAS. The issue is not "slow speed aggressive maneuvers" , but turns in level flight in cruise, above 90 km/hr, after the SAS yaw channel is supposed to be automatically disengaged. At cruise speeds, the fin is big enough to keep the helicopter stable in the yaw axis, and to maintain coordinated turns, so that operation of the SAS yaw axis would otherwise be redundant in cruise speed in straight flight, and counterproductive in cruise speed in turns. As for the big block on top the flight canopy, that applies to the SA-342M, but not the SA-342L or SA-342Mistral. Parasitic drag would be minimal for the 2 latter, and the two side-mounted rocket pods would have balanced parasitic drag for the SA-342Mistral. In any case, in straight and level cruise flight, the aerodynamic forces acting on the fuselage achieve a balanced state, as pedal would have been adjusted to keep the ball in the middle; initiating a roll to turn would not require any more pedal input in order to keep the turn coordinated. The question should be asked to a real experienced SA-342 pilot: does the pilot need to input any pedal while rolling into a bank in forward cruise flight. If so, to what extent. If this is the case, what is the behaviour of the helicopter if pedal is not input as the aircraft is rolled into a bank, as it affects slip/skid, and the streamer on the windshield.

Thanks for that. Further reading the manual, the autopilot does not have a yaw channel. In the Flight Manual Supplement 13, section 0.5, it states: "Since the autopilot functions only in cyclic ((pitch and roll), the pilot must continue to operate the directional pedals and collective pitch when necessary." It wouldn't make any sense when on autopilot, to have to continually having to input pedal during turns in order to keep them coordinated (ball in the middle) and no slip or skid.

I stumbled upon this thread: ED Forums » English » Licensed Third Party Projects » Polychop-Simulations » SA-342M Gazelle » Bugs and Problems » Something wrong with flight dynamics. Focha is right, and he's a real, current and experienced helicopter pilot flying Airbus Helicopter products. I haven't flown helicopters in 40 years. In a bank in forward flight, the vertical stabilizer should keep the helicopter in a coordinated turn: ball in the middle, or close to it. In effect, the yaw axis resists the turn resulting in the aircraft side-slipping. It seems that turn characteristics of the flight model in forward flight, require that pedal be added in the direction of turn. But in reality, the vertical stabilizer should otherwise keep the aircraft in a coordinated turn with the ball in the centre and the streamer lined up in the centre. There was also a comment that some cyclic input into the bank is required to maintain the bank; in a coordinated turn, the cyclic should remain centered once the aircraft is banked. This is another indication that the aircraft is side-slipping. All conventional (with anti-torque tail-rotors/fenestrons) helicopters have practically the same handling characteristics. As explained in the FAA Helicopter Instructor's Handbook FAA-H-8083-4, p 10-6 (which is generic): "To enter a turn from straight-and-level flight, apply sideward pressure on the cyclic in the direction the turn in made. This is the only control movement needed to start the turn. Antitorque pedals are not used to assist the turn. Airplane pilots transitioning to helicopters attempt to use the antitorque pedals as they would rudder pedal." Buses and Porsches alike tend to skid in a turn. That's the law of physics, not handling characteristics. Same with helicopters. A SAS would not induce unfavourable flying characteristics by inducing a slip towards a level turn, thereby making it harder to fly. In any case, if the SAS was turned off, it would fly like any other single rotor helicopter equipped with an anti-torque rotor/fenestron. I never flew a helicopter with a SAS. Just basic boosted controls in the Bell 47, Bell 205 and Bell 206, and electrically trimmed cyclic in the Hughes 500C. They all basically flew the same and the Gazelle should be no different: no pedal input needed in cruise flight in a level coordinated turn. P.S. Your last comment makes no sense.

Any reaction, comments, denials, corroboration, discussion?

Description: Flight model, pedal input during level turns DCS Version:>1.5 In the simulation in level flight, pedal is required during turns in order for the helicopter to make coordinated turns: i.e. ball in the centre. In the simulation, without pedal input in level turns, the helicopter slips: ball slides to the inside, and streamer points towards the turn. In other words, after banking the helicopter, the helicopter resists yawing in the direction of the bank. In a real helicopter, pedal input is not necessary to make coordinated turns. Starting in cruise flight with the ball in the middle, coordinated turns can be made with feet on the floor. The flight model does not make the aircraft pleasant to manoeuver. The Belsimtek UH-1H flight model accurately replicates coordinated forward flight level turns: no pedal input required.

I flew Bell 47G4A, Hughes 500C, Bell 206B and Bell 205, the latter 2 only 25 and 70 hours. The first 2 about 500 hours each. I won't get into all the Airbus and Boeing time I have. It's been 4 decades ago, but I do not recall ever having to add pedal in a turn at cruise. Once the pedals are set at a steady cruise speed, a roll into a turn does not need pedal. It could be that the Gazelle has different flying characteristics, and that's why I suggested elsewhere an opinion from someone who has actually flown one. But with such a large fin, I think it unlikely that it's required. What is annoying with the FM, is having to recenter the pedals using the ball and streamer after completing a turn, since unlike an airplane, the pedals don't center themselves in a helicopter: i.e. there is no pedal (aka rudder) trim. BTW, the simulation is really good at giving me the same perspective and feel of doing an approach as the real thing.

The only issue I have with the flight model is that in forward flight and in a turn initiated by a roll, the aircraft slips (the ball swings towards the turn) unless you add a little pedal into the turn. That is, the yaw axis resists the turn, which is uncharacteristic of a helicopter, at least the ones I flew; especially with a helicopter with such a large vertical stabilizer. The resistance to yaw reminds me of flying RC helicopters with a yaw gyro: to turn in forward flight, you have to add pedal along with roll. BTW, I like flying the Gazelle with autopilot/SAS off.

To put some context here: it's flying perfectly level with no input because it is, after all, a simulation; the math is perfect. It is perfectly trimmed and there are no external forces affecting the model, such as turbulence and varying wind. Plus, in the examples given, the ground is perfectly flat. In the real world, the air is never perfectly still, even if the wind is reported to be calm. During daytime, you also get convection due to solar heating. All these factors make the helicopter depart from its state of relative stability. My suggestion: induce some instability, such as slight turbulence. The helicopter, being dynamically unstable, once an external forces is applied to it, will continue to diverge, such as keep on rolling unless human input (or autopilot/stability augmentation system) brings it back level. I flew the Hughes 500C for a little while a long time ago. The most it would fly hands off after trimming it was about 10 seconds. I hear that the MD-500D with the T-tail can fly hands off for much longer, like minutes. There is also the possibility that the flight model is too stable or rather, not dynamically unstable enough. That is, it will tend to maintain a stable state after upset. Dynamically unstable means that once upset, its attitude continues to diverge, and helicopters are dynamically unstable. I've never flown it in real life, but it should be an easy question to ask an experienced Gazelle pilot: 'with the autopilot/SAS off, how long will it stay stable hands off the cyclic?'

Great stuff! So what's the problem with Eagle Dynamics incorporating all this within the official package? It's not as if the authors/designers are asking for money?

I've placed a few. They indicate wind direction ok, but not strength, unless you think that vibration is somehow an indication. When a wind sock is straight out, you have a good 20 knots. If it barely hangs, you've got about 5 knots. Half way in between would give you 10-15 knots.

How about just helipads that you can just position anywhere you want to land on. All we have now is this 4 pad FARP heliport base of operations, and the topography has to be really flat in order to position them. Presently, if I want to land on the side of a mountain, I place a building with a flat roof to land on, imagining that its a helipad. It isn't that realistic but it works. How about real helipads that don't take a city block in area. Also have lights around the pads for night time operations. Come to think of it, would also like to be able to place flarepots, so you can light up runways and helipads at night without electricity.

Wars do often take place in bad weather. What's the point in surviving an air-to-air encounter when you're going to crash your airplane on final because you can't fly on instruments? The weather implementation in DCS is getting really good, and actually surpassing some features in the visuals of the big 6 axis full motion flight simulators. This capability is wasted if most stick to fair weather flying.

Oops!, my bad. I meant Flanker, not Falcon. The Flight Director worked as it should in Flanker [1]. They rewrote the code completely for Flanker 2, but they seemed to reinvent the flight director, and not too well. Realism, accuracy and fidelity are what makes these sims stand out. They should correct this function Since no one has complained before except me, seems like everyone around is a fair weather flyer. Not too many people do hand flown ILS approaches in 400 meter visibility it seems.

Any chance to fix the SU-27/33/25 flight director? It used to work great under Falcon 1, but since the rewrite of Falcon 2, it never really worked the way it should have. The flight director are the two needles in a cross-hair inside the ADI Attitude Indicator. It gives roll and pitch commands. There is too much hysteresis in the pitch axis and is generally not smooth at all. Changes should not be abrupt. It's used by real pilots especially to fly an ILS. The horizontal bar should be placed on the index at the centre of the instrument. But if you do that, you overshoot. It works better if you go half way and not try to put the horizontal bar on the centre point of the instrument, but that's not how a real one works. Plus, another thing I discovered lately. On an ILS, about 500 meters AGL, the localizer and glide slope needles on the ADI go suddenly off scale. The needles on the CDI (course deviation indicator) should also reflect the needles on the ADI, but they are always off-scale. The easiest way would be to find the original software module in Falcon 1 and convert it to whatever software they're using now.

Implementation of single heli-pad static object. Try putting a helipad on a side of a mountain: impossible because the only implementation of a helipad is a huge heli-base, and the ground has to be fairly level. But you can put a building like Garage A on the side of a mountain and land on it, but it's fairly unrealistic. Implementation of lamp-posts and lights static objects. Plus, if you try to light up a particular patch of ground in the middle of nowhere at night, it's impossible. So at least be able to place individual lamp posts, or individual taxi/runway lights. That way, I would be able to place a single heli-pad and have it lit up, or at least put lights around it. Night vision devices don't count, as the point is not to fly in daytime-like conditions, but to require some reference to the flight instruments when the horizon or most ground reference are not available: the black bowl effect.

The SU-27 flight director logic (also affecting HUD commands) has been broken ever since they redesigned the whole thing in the production of Falcon 2.0. The original Flanker had the flight director working correctly. it seems that the (ILS) Localizer steering commands are related to homing to the runway threshold, rather than correcting the angular difference between the extended runway centreline and the aircraft position. Also the 'Return' mode transitioning to the 'Landing' mode is unrealistic. Too steep an intercept to the 'Return' waypoint leads to overcorrecting in the 'Landing' mode. They had no concept of what a Procedure Turn is. As for altitude commands, the vertical commands are way too sudden. Way too much hysteresis. If they just reduced the sensitivity of the command bars by half, that would be great progress.