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Curly, interesting references, thank you for spending the time digging them up. I find your calcs a bit hard to follow though, as values are introduced without explaining where they come from. I get different results when performing the same calculations. Givens Based on the AD0069271 report: Rudder hinge moment H = C_Hr * q* s_r * c_r, where s_r is the area (ft^2) and s_r * c_r is the area moment (ft^3). s_r * c_r, per the report, is 9.72 ft^3. q = rho*V^2/2, with air density rho in slugs/ft^3 or .00237 at SLS. V is in ft/s. M.4 At M.4, .4*1126=450 ft/s, C_Hr as stated is .23 for -25° rudder deflection at 0° yaw angle H = C_Hr * q* s_r * c_r = .23 * (.00237*450^2/2) * 9.72 = 540 Curiously, the unit for the hinge moment is never stated as far as I can tell, but it can probably be assumed to be ft lbs, as they haven't used sane units anywhere else. ;) Assuming (and this is a big assumption) a completely linear relationship between pedal movement and rudder deflection, and assuming 6" of forward pedal travel, the pedal force at half a feet of travel should be twice the moment in ft lbs, or 1080 lbf. That sounds a whole lot more plausible IMNSHO. My estimate is that 25° of deflection at 265 KTAS would rip the fin clean off - it's just not something you'd build aircraft for. Note that the data are from 20% scale wind tunnel tests. To get there with a mere 74 kgs of pressure on the pedal would mean you could essentially do it by accident while reaching for a map. M.2 Repeat at M.2: C_Hr = .24, TAS = 225 ft/s. H =.24 * (.00237*225^2/2) * 9.72 = 140 ft lbs, for 280 lbf of pedal force. No comment on the M4.0 case presented... :pilotfly: Pedal travel Where did you get the 6" pedal travel figure from? DTI639028 gives 3.75 inches of travel, center to maximum deflection, based on two war-time reports. Sounds rather limited to me, but then again - I rarely look at my feet when flying. Three, six or eight inches has a profound effect on the final results, so this is an important figure to get right. Crabbed approaches I do not understand your comment regarding the crabbed approaches up to 25 knots [of xwind]. The rudder is effective for crabbed approaches up to direct xwinds equalling the true airspeed, at which point you will be hovering with the nose 90° off from the final approach course... :) Jesting aside, the rudder isn't used as long as you are crabbing. There is a recommendation in the FM not to land with xwind components in excess of 25 knots, but that's likely to be due to either structural limitations regarding the crab angle you can safely touch down with, or directional control issues on the rollout. It does indicate that you shouldn't touch down crabbed, so the rudder authority should be sufficient to remove most of the crab prior to touchdown with the 25 knots component. In that case, the air speed would be 120 + 2.5*5 = 132.5 KIAS (and KTAS, assuming SLS), so a 25 knot crosswind equates to 10.7° of crab. That's anecdotal evidence of the amount of rudder control available with normal control forces, FWIW. (Pg. 6-8 of the F model manual is also interesting, regarding rudder control. Note the lack of warnings regarding overcontrolling at high airspeeds. Had pilots been able to deflect the rudder to angles posing structural hazards, there would have been such warnings.) Rudder deflection in various flight conditions Going backwards, the DTI639028 report figure for desirable rudder control force, from the 1945 US Army/Navy agreement, is 180 lbs. This gives a hinge moment of 90 lb ft. At 130 KTAS (220 ft/s), C_Hr = H/(q * s_r * c_r) = 90/(.00237*220^2/2*9.72) = .16 220 ft/s is, coincidentally, almost exactly M.2 so we have a data point available without extrapolating. A .16 C_Hr will give you a little less than 20 degrees of deflection with no yaw. Finally, let us move on to M.8, 900 ft/s. With no yaw, 180 lbs of control force would again give you 90 lb ft of hinge moment. C_Hr = H/(q * s_r * c_r) = 90/(.00237*900^2/2*9.72) = 0.01. With no yaw, that's 1.5° or so of deflection. Yes, it can be argued that the maximum rudder forces specified here are very conservative. Still, the fact remains - you're not going to produce much deflection at high airspeeds. References It would be easier if you stated what information you think is pertinent in the various references given. I'd stay clear of the DWC lecture slides, which the 12.5 figure stems from. I found a couple of 'interesting' things in them, and the book they state they are based on doesn't seem solid either, after a bit of googling on it. Rudder efficiency vs flight dynamics The rudder is efficient if it can generate a beta angle. This is what is important for a xwind landing. The turn, or lack thereof, generated by that beta angle, is flight dynamics/aerodynamics. This has amused me as this thread has run its course. :) Rgds, /Fred

Ah, my bad - didn't realize it could be a module issue. If it works in the A-10C, the tanker does what it is supposed to, obviously. I'll let those who know answer for the module but by elimination it would seem the module is at fault. All in all, I think the navigation infrastructure and how it relates to the various modules is a mess, getting worse with every release. :/

A/A TACAN has been working since the beta days of A-10C, and I haven't heard anything about it being broken as of late. What do you mean by "X2"? Channels should be on the format "nnX" or "nnY". Did you put the TCN unit in the aircraft in Tx/Rx mode, T/R? If it is on receive only, you won't get distance readings as the DME part of a TCN is a transponder responding to the interrogations you send out. Cheers, /Fred

Back course approaches are the exception rather than the norm, and are not commonly found (read that as: pretty much non-existent) outside of the US. Modern localizers are directional to the point where there isn't much energy wasted to form a usable back course.

And that's probably the problem for a lot of virtual aviators - overreliance on the HUD as their primary (or only) flight instrument. It's an easy trap to fall into, as it really aids in the transition from real life to the confines of a computer monitor. Solution: Have your virtual alter ego lean back, fly using primary instruments (i e the gauges) and use the gun sight (HUD) for weapons delivery.

Right you are. In the A-10, even the C, it's essentially a gun sight with SA help added. The gauges are still the primary reference when flying. Certifying a HUD as a primary flight instruments adds whole new levels of complexity to the certification process.

If you do a bit of searching in these fora, you'll find quite a few rather lengthy threads about how a HUD works and why scaling isn't feasible. This thread isn't the best, but it is a start. :) Rgds, /Fred

A real HUD does not obscure things the way our simulated one does. That's from experience with the real thing, not YouTube. The OP is right. However, it's probably not easy to find a way to make the pixels on our screen behave correctly. Just blending in whatever is in the background would not do it IMHO. You're trying to represent a very narrow bright line with a less narrow line.

Ehm. Post #2? :)

The 133.00 MHz tower frequency is in the VHF band. The ADF works off NDB beacons in the kHz range, so that one won't detect the tower transmissions. The NDBs and their frequencies are in the map, and are tuned separately in the aircraft. The UHF comes with a direction finding mode allowing for direction finding of transmitters on the UHF band. Those would be the 200+ MHz frequencies. Not sure if this is implemented. You also have the FM radio with homing capability - check the manual. Been a long time since I messed with this, so I'll leave it to someone else to sort out the details.

A patch or two ago, it did. You might find the manual pip bombing section of the 86F manual interesting. It states to open the speed brakes for the dive. Cheers, /Fred

@Warthog, sorry, you can't have an elevation in ft above a Kohlsmann (altimeter subscale) setting of 1013 hPa. For subtraction to work, both terms have to be of the same unit. The hair has now officially been split. ;) I see what you mean though, and you have the right idea. QNE: "What indication will my altimeter give on landing at...(place) at...hours, my subscale being set to 1013.2 millibars (29.925 inches)?" The code QNE is not, however, officially defined in international aviation, unlike QNH and QFE. The Q codes were established to simplify comms with morse code way back and that one hasn't made it into the standards of today. If your altimeter can't cope with the current atmospheric pressure, you don't have an altimeter and are not legal to fly if it is require equipment. It has happened, and aircraft have been grounded... but only due to high pressure, while I've been around. That's a story in itself. The fast jet boys were stuck on the ground but I went flying, as my altimeter had a wider range. In addition, it was one of the coldest days of the year at a high latitude, so the density altitude was way - way - below sea level. Alone and without filling the tanks to the brim I got impressive performance out of the old kite. :) Cheers, /Fred

Ah, so I should have written something along the lines of: (My boldface.) Gee, I wish I would have thought of that. ;) I do not believe it is ever used for that. If you can't go to QFE when manoeuvering for takeoff/landing, you'd use QNH instead. Using flight levels would mean constantly having to apply a correction to your altimeter reading in order to know your altitude over the ground. If the altimeter is frozen, it is broken. I'd use the backup, present even in most spam cans. :) Cheers, /Fred

And that's the point - in DCS, it doesn't. There only one conclusion to be drawn: DCS has unearthed a flaw in reality. The real world will be updated to implement this in the next patch. :pilotfly: Kidding aside, I'm sure we'll see convergence eventually. Cheers, /Fred Edit: Wasn't there a post identifying or even linking those reports? I can't seem to find it.

As for categories: HF, VHF and UHF. (Technically, I guess 40 MHz is above the HF airband used today, but the distinction should be clear enough.)

Same here. Unless "we" means "me and my good chums here at the offices in Montreal" it's not something "we" are free to define. If you do work in Montreal, you should be updating your publications to contain that definition rather than spend your time posting in forums... ;)

Exactly which are the facts you contend? It's not me you are disagreeing with, but rather ICAO. The only way you can effectively disagree with ICAO is to live in an exotic place like N Korea or to have your country's regulatory authority file a point of non-compliance in your national regs. ICAO write The Book. While everything you can find on the net is generally true and factually correct, I'd go with the ICAO definition in this case.

The P-51 has two trim tabs. One for in-flight trimming, controlled by the pilot, and one which the ground crews can set to rig the aircraft. Guess which one is which? ;) As for the rest, a good start would be to have a look at what the controls actually are up to in th RCtrl+Enter window. Trim tabs have no effect on the control surface/stick position while static on the ground. They work through the aerodynamic forces on the trim tabs. The link in my sig may just be an interesting read, even if not strictly on topic. Cheers, /Fred

Yes, and no. Yes, as it is most definitely outside of the flight envelope that I we can reasonably expect the simulation to cover. But also no, as the beauty of this is that it effectively removes the aerodynamic loads and reduces the problem to one of basic rigid body mechanics - which should most definitely be in place, and also appears to be there. As far as I know, you only have the basic moments of inertia in the model though. This means that for any asymmetrical loadout where you also have products of inertia, the results will not mimic what they would be in real life. It's not something which would be obvious though - quite the opposite, I'd say! Very much agreed, and those who know me in these forums probably agree that I'm not among those who are easy to please or slow on the trigger. :badmood: :D

That was my first thought as well, but =Mac= has a point. It is basic physics. The mass distribution of aircraft makes almost all aircraft strive for a flat spin, with aerodynamic forces acting against this tendency to create the various more common spin modes. At the apex of a vertical climb, the air speed is zero so the only aerodynamic force is that from angular velocity, which should be pretty marginal. Hence, the spin should indeed tend to flatten. As I wrote earlier, it is highly dynamic so the tendency may well be hidden among a plethora of other influences... but it is a very interesting application of flight dynamics in the DCS environment. :)

Altimeter settings are used to compensate for the variations in atmospheric pressure. The atmospheric pressure (obviously) varies both over time and with location. Set QFE, and the altimeter will give you your altitude above the reference point used. If you are on an approach, you'll be given the QFE for the threshold of your destination runway, otherwise for the aerodrome reference point. QFE is easy to manage without reference to charts (for field/threshold elevation) and can be set independently for any location you happen to be parked at. The drawback is that you cannot separate QFE traffic by altitude if they're from different fields, and that you will not know your margin to obstacles or the ground off the airport, as the elevations in the maps are given relative to mean sea level. It has seen use in many air forces, is still used in some places, and is still popular among glider pilots. It is less common now than it was only a couple of years ago though - the trend is to switch to QNH for greater interoperability. Set QNH, and the altimeter will give you your altitude above mean sea level, AMSL, at the reference point/field. If it is cold, the altimeter will overread so you need to apply a correction to all minimum altitudes. This is not something you typically need to be concerned with in DCS, as your virtual alter ego is quite happy to accept the increased risk of the reduced safety margins. In the military arena, a force QNH is sometimes (often) used, to ensure a common reference among participating aircraft without going to standard pressure settings and losing a readily available ground referenced altitude. Finally, there's standard pressure - QNE (not officially defined in ICAO Doc 8400) - which gives you your uncorrected pressure altitude, independent of any geographical location. This is nice when separating traffic by altitude. And I think some clarifications are called for, to avoid confusion. I hope they can be accepted without causing offence. No. Yes. Also Yes, even though you technically have to be at the (elevation of the) reference point for it to be absolutely true. If you are above a surface which is at MSL, and under standard atmosphere conditions. No, you use the barometric altimeter for altitudes and the radio/radar alt for heights. In addition to the reason given above, they're part of the procedure, indicated differently in the plates and cannot be exchanged at will. Yes. :) No.

17 degrees is 17 degrees. In the real world, it is always FROM. In the DCS mission planner, it is still TO. From the in-game ATC, I think it has been both but I would hope it is FROM by now. Should be apparent after the first approach which it is. :) I don't bother flying the propeller aircraft in crosswinds for now, and I would recommend you to do the same and save yourself the frustration. /Fred, taildragger rated

Ah, now I see what you mean. Absolutely crazy, but interesting. I suspect it will never have been tried intentionally in real life. :D It's pretty dynamic though, so the actual results would probably vary a lot. I'll make sure to watch the videos later.

What should happen, and according to what source? The aircraft seems more reluctant to spin than what I would have anticipated, based mainly on anecdotal evidence, but I would have to have better source material to call it considerably miscalculated. It appears you have found souch sources? Please share, it would be very interesting to read. Ditto for the flat spin characteristics, which I haven't seen described in detail anywhere, leading me to assume that flat spins weren't easily entered. Rgds, /Fred

All those did amazing things which have yet to be introduced into recent simulations. I have a horrible feeling they'll show their age though. If anyone tries running them on a modern PC, do let us know the outcome!