Hi Jano, Thanks for the video links... these were great...
So far I have had 5 others, aside from myself, trying to get to touch the R or L drogue, and while some got quite close and were able to maintain a close position, several factors came into play which made it difficult, if not impossible... The tanker used is the 'victor', probe-drogue type, flown on autopilot at 12000 feet (STD 29.92), 220 knots on either 180 from Paris LFPY, or 360 on the return. I usually turn N shortly after Toulouse in the south... So far, as the other aircraft, have had Citation-II, Mirage_F1, m2000, f16, and ???... A big thank you to them for joining in and trying... And I understand some screen shots were posted on the PAF forum, but still to find these... a link would help... I also tried with a 2nd victor, running in a 2nd machine... Oh, and I always use mpserver14.flightgear.org, Switzerland, and perhaps attempts while using the SAME fgms server may be better... but still saw the following assumed due to 'lag' problem when flying victor to victor > where this is the closest you can see the following plane, > but in fact he see itself very close to the drogue This difference between whether you are looking from the aircraft to the tanker, or from the tanker to the aircraft is certainly ONE of the problems. Usually the tanker will see the aircraft still back some 10s of meters behind the drogue, while the pilots sees the drogue up very close, perhaps even touching... And assume it can be the reverse of this... > http://wiki.flightgear.org/Mp-patch Have downloaded and am looking at your wiki lag patches with an aim to patch my 2.11... in Windows 7 and Ubuntu... but not sure how far I will get... It would certainly be nice if both pilots saw the same scene ;=)) But this is not the ONLY problem... > basically the mp sending rate is fine with 10 pps Well yes if the packets flow, but many things do seem to interrupt that flow... One of the biggest is F3 - take a screen shot - This seems to stop packets for a seconds or more... Loading a new scenery tile can be another... new weather metar, although in the victor I usually select simple Fair weather... but there seems to be a number of things that 'change' the packet flow... I even suspect mp chat causes small blips... There is already some form of predictive code in 2.11, but this to not yet very accurate or successful, but seems a very good start... If the aircraft IS maintaining close proximity to the drogue, and I press F3 in the tanker, the tanker seems to slide forward faster and further than it should! So the aircraft pilot sees the tanker quickly move away... accelerate and moves forward... quite un-nerving... And this can happen even without a heavy F3 event... perhaps even due to system thread changes, ie nothing to do with the running fgfs... Now if [s]he does nothing but hold, usually things will settle back into close proximity, but the pilot has LOST some visual clues aiding to maintain position so by the time things resettle [s]he is no longer so near the drogue ;=(( So I must take another look at this fill-in code, and would like to hear from the person or persons who implemented it... and understand why the very apparent slide fast forward, and what controls how quickly the position returns to that of the current packets after such an artificial change... any README, links, etc... And then there is how will your 'lag' correction effect this current extrapolation code? If at all... So lots of things to explore here ;=() Over the coming days I will try to maintain my victor tanker runs... but it too can be quite stressful even just watching and chatting... Maybe later try an E-W run, since you do mention some differences depending on direction... So still invite others to try, but they should read and understand the above - it is difficult if not impossible - so expect more of the same frustrating efforts until some more CODE changes can be put in place... As one trier sort of put it - it is like the tanker has some 'shield' around it... things are good while you close in, but at very close proximity all HELL breaks loose ;=)) Have FUN! Regards, Geoff. On Thu, 2013-04-18 at 08:18 +0200, jean wrote: > Hi Geoff > > i guess you are seing something like that: > > http://www.youtube.com/watch?v=VWn6_RFp97Y > > where this is the closest you can see the following plane, but in fact > he see itself very close to the drogue > > and what you want is like this: > > http://www.youtube.com/watch?v=kGHRDrc_n98 > > you should have a look at this page, wip but working fine for the few > pilots testing it : > > http://wiki.flightgear.org/Mp-patch > > basically the mp sending rate is fine with 10 pps, but you need a way to > compensate for the lag. > > I can't try a refuel with you before this WE, but i will if you are > still flying the victor somewhere. > > jano > > > > NOTAM: > > > > To flyers who fly 'probe' enabled aircraft in Europe... or > > even if NOT... > > > > I will be flying the 'victor' refueling tanker for the next > > few days from KFPY, south 180 track, then turn around at the > > southern mountains, north on 360, at 12,000 feet – FL120 > > STD QNA – and am interested in 'hot' flyers who want to try > > air-to-air REFUELING (AAR) in suitably equiped aircraft, > > well ANY aircraft... > > > > The tanker will maintain, under autopilot, 220 knots (KTAS), > > at the said 12,000 feet, either 180 or 360, under the callsign > > GA006. > > > > The flights will commence about noon, or before, UTC, and > > close about 20:00 UTC. > > > > The track can be followed using http://test.fgx.ch, or other mp > > map URLS. Click on 'GA006' to localize... > > > > Reason: > > > > (a) I have tried with several aircraft over the last few days, and > > learned that this is QUITE difficult, but I hope NOT impossible! > > > > (b) The present suggested pps (Hz) is 10 when you set up –multiplay=, > > but FG 2.11 has fill-in extrapolation code when fgfs packets > > do not arrive in time, so maybe this is too high. This is the basic > > question... > > > > So the idea is to reduce this IFF this fill-in code helps, ie does its > > job... > > > > The theoretic idea is that with this code we can reduce the > > bandwidth used by 10 Hz to perhaps 2-4 Hz, but this needs > > to be FULLY tested, and confirmed... > > > > Now I have tried this over several day, in several aircraft – > > A-10, f-14b, a4 and failed, FAILED to touch the trailing > > drogues... it is TOUGH... autopilots help you get to the 'zone' > > but it needs manual flying to get to the RIGHT PLACE... > > > > If you are using a joystick maybe you need to even adjust > > the dead spot and the 'sensitivity' of the inputs... lots of > > learning, understanding and doing fgdata xml changes... > > > > And I have had a few pilots joining in ad hoc, but so far > > no one has actually contacted with the trailing outer wing > > drogues... The 'victor' can refuel 2 aircraft at a time... and I > > would LOVE to see/capture that... > > > > One, french I think, got so frustrated at his attempts, began firing > > missiles at the tanker. Thankfully, he MISSED, but was CLOSE ;=)) > > > > Also if you alert me to your attempt to refuel from my tanker, via > > mp chat, email, fgcom, … AND I am on board at the time -: > > > > (a) I will offer a VIRTUAL bottle of good Bordeau rouge to the first > > pilot who maintains drogue contact for say a minute, or more ;=)) > > > > (b) I will take some screen shots and post them. > > > > Be warned, during a screen shots (F3), fgfs stops sending mp > > packets for up to a second or so, and in the close fgfs the fill-in > > (extrapolation) code is activated, with some interesting, and > > sometimes quite alarming effects... > > > > Also I have heard others mention that the live metar update can > > also cause mp packet delays. The tanker will be flying under the > > 'Fair weather' scenario to avoid this. Maybe you should choose this > > as well... > > > > I really seek help from other pilots to analyse this multiplayer > > bandwidth situation. We have chosen 10 Hz, but WHY? > > Can less than 10 Hz be used with no adverse effect? That is > > the BIG question... > > > > Simply, what really is the optimum packets-per-second (pps) rate? > > Maybe it changes depending on circumstances... > > > > We know the lower the Hz the lower the bandwidth used by > > FGMS servers... but can the extrapolation code fill-in for > > the missing packets? > > > > Is 10 Hz good? Should it be higher, or lower depending on > > circumstance.. Lots to learn... > > > > Of course I am sure there are OTHER ideas... > > > > Hope you can help, and have some FUN at the same time;=)). > > > > Look forward to seeing you on my rear view... and I will > > take some pics... > > > > Regards, > > Geoff. > > > > CC: to users list... > > BCC: to others... > > > ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
