Re: [Flightgear-devel] UAV Heli and Matlab
Melchior FRANZ wrote: > * Georg Vollnhals -- Wednesday 14 June 2006 11:57: >> Melchior FRANZ schrieb: >>> * Georg Vollnhals -- Wednesday 14 June 2006 03:02: Take the BO105 and goo for a straight and level flight with 100-120 knts. Then push the collective down. [...] ^^^ > >>> That's "translational lift". > >> No. Translational list is an additional lift component related to >> helicopter speed against the air and will start at about 12 to 20 knts > > Pardon? You spoke about 100-120 knots. I said it's translational lift. > You disgree because translational lift starts with 12 to 20 knots?!? > Doesn't make the least sense. > > m. > > > ___ > Flightgear-devel mailing list > Flightgear-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/flightgear-devel > I think the 100-120 kts figure is irrelevant, he was talking about autorotation there, which has pretty much nothing to do with what we are talking about now. We are mixing two effects here, ETL and transverse flow effect. In my original post I was talking about ETL, and failed to mention transverse flow, as well as LTE, both of which should have been on that list. These two effects are also related to dissymmetry of lift, retreating blade stall and delta-3 blade hinges. Here are some excellent descriptions of the difference between the two. Point was, there are a lot of important effects missing from the simulation or not realistically implemented. http://helicopterflight.net/translational_lift.htm http://www.dynamicflight.com/aerodynamics/transverse_flow_eff/ http://www.dynamicflight.com/aerodynamics/translational_lift/ http://64.233.161.104/search?q=cache:Sy8Mi3NkuKAJ:www.baseops.net/ft_rucker/HELO_Aerodynamics.ppt+translational+lift&hl=en&gl=us&ct=clnk&cd=6&client=firefox Josh ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Unless you get REALLY small the accuracy should be the same as full scale. But close to the ground the ground effect makes a big difference. It happens when aplane flies at an altitude less than half its wingspan. Basically the air underneath "can't get out" and creates tremendous additional lift. On Wed, 14 Jun 2006 6:59 am, Correu PelDavid wrote: > The discussion seems to be getting hot.. > > Regarding the heli model: Could it represent an R/C helicopter model > fine enough to synthonize an autopilot to be ported afterwards to real > (R/C UAV) life? > Would it work for slow velocities and near to ground flights? > Would it work for higher (not much) altitude and agressive manoeuvres? > > Thanks, > > David > > 2006/6/14, Melchior FRANZ <[EMAIL PROTECTED]>: > >> * Georg Vollnhals -- Wednesday 14 June 2006 11:57: >>> Melchior FRANZ schrieb: >>> > * Georg Vollnhals -- Wednesday 14 June 2006 03:02: >>> >> Take the BO105 and goo for a straight and level flight with 100-120 >>> >> knts. Then push the collective down. [...] ^^^ >> >>> > That's "translational lift". >> >>> No. Translational list is an additional lift component related to >>> helicopter speed against the air and will start at about 12 to 20 knts >> >> Pardon? You spoke about 100-120 knots. I said it's translational lift. >> You disgree because translational lift starts with 12 to 20 knots?!? >> Doesn't make the least sense. >> >> m. >> >> ___ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
On Wed, 14 Jun 2006 11:57:39 +0200, Georg wrote in message <[EMAIL PROTECTED]>: > Melchior FRANZ schrieb: > > * Georg Vollnhals -- Wednesday 14 June 2006 03:02: > >> Take the BO105 and goo for a straight and level flight with 100-120 > > > knts. Then push the collective down. [...] > >> Try it with the BO105 - see what happens? > >> You are not only able to hold height with pulling the stick back > >but to > climb with up to 1500 ft/min until speed is low. > > > > That's "translational lift". You know, the thing people are claiming > > isn't implemented. :-} It's not realistic (as Maik himself says), > No. Translational list is an additional lift component related to > helicopter speed against the air and will start at about 12 to 20 knts > (depending on type of helo). This is a real big addition lift > component >together with (an unwished) roll and yaw component. > > but I'm not sure about the "dropping like a stone" thing. Normally, > > people compare a fully loaded real helicopter (because they are > > sitting in them as passengers together with several other people) > > with an unloaded sim helicopter. Put more weight into the bo, and it > > sinks faster, as one would expect in RL. > > > > m. > "falling like a stone" might be the wrong expression but was told me > by a RL pilot and demonstrated afterwards in a "hot" autorotation for > a short time from 2000 to 1000 ft. It is pretty impressive and the > vertical speed naturally depends on the type and configuration (ie > weight) of the helo that you fly, our BK117 should come up to more > than 2000 ft/min, a BO105 will be have some other numbers but > generally comparable. > You understand what one is doing when reducing collective? You reduce > the common blade-pitch angle to (nearly) zero (depending on the type > of helo you are flying). Of course, going into a heavy flare will > give you some lift for a short time until your horizontal kinetic > energy (speed) is reduced. But when I asked one of our experienced RL > pilots ..define "experienced." We need somebody experienced in autorotation, and these guys are rare and expensive. > about this scenario and what would happen, he told me that he could > (if ever) hold altitude for a *very* short time by pitching back but > could not make the bird ascend remarkably (what our FG helo does). > > OK, after all I want to say once again that I am not the real expert > for this, we should have an *experienced RL helo pilot* who is also > interested in flightsims to tell us what he thinks in general and > detail about our FDM. > But as I was very keen to learn all about helicopter flight behaviour > and technics and comparing different helo sim flightmodels by checking > the opinion of RL helo pilots I *just want to share* all I know with > you. People simply should be advised that there are very diffent views > regarding the actual helo FDM. > > I would feel pretty bad if we announce our helo FDM as "realistic" as > we have some nice fixed wing aircraft with "real life pilots and a/c > owners" approved flightdynamics, this would be bad for FG in common. > > Just my 2c, this discussion will probably never end :-) -- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Ahh, ok. I stand corrected. * Georg Vollnhals -- Wednesday 14 June 2006 12:37: > Simply because it is established at low speed and will not *change* > anymore at high speed. Well, that's not true. It can. I'm not really a helicopter engineer/physicist. I can only read about things like these. I should look more often into the Helicopter Handbook. If only we could find someone who can read *and* write the appropriate code. :-] m. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Melchior FRANZ schrieb: > * Georg Vollnhals -- Wednesday 14 June 2006 11:57: >> Melchior FRANZ schrieb: >>> * Georg Vollnhals -- Wednesday 14 June 2006 03:02: Take the BO105 and goo for a straight and level flight with 100-120 knts. Then push the collective down. [...] ^^^ > >>> That's "translational lift". > >> No. Translational list is an additional lift component related to >> helicopter speed against the air and will start at about 12 to 20 knts > > Pardon? You spoke about 100-120 knots. I said it's translational lift. > You disgree because translational lift starts with 12 to 20 knots?!? > Doesn't make the least sense. > > m. > > > ___ > Flightgear-devel mailing list > Flightgear-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/flightgear-devel > > Simply because it is established at low speed and will not *change* anymore at high speed. Only at the transition phase [groundeffect] (up to 5 knts) -> loosing lift until 12-20 knts -> [translational lift] you will then have that heavy upwards with same powersetting, need to pitch down and correct roll-tendency and some yaw effect (without changing collective) due to increased tail-rotor efficiency (is also a rotor-disk with tl-effect, only other angle than main rotor). Georg ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
The discussion seems to be getting hot..Regarding the heli model: Could it represent an R/C helicopter model fine enough to synthonize an autopilot to be ported afterwards to real (R/C UAV) life?Would it work for slow velocities and near to ground flights? Would it work for higher (not much) altitude and agressive manoeuvres?Thanks,David2006/6/14, Melchior FRANZ <[EMAIL PROTECTED]>: * Georg Vollnhals -- Wednesday 14 June 2006 11:57:> Melchior FRANZ schrieb: > > * Georg Vollnhals -- Wednesday 14 June 2006 03:02:> >> Take the BO105 and goo for a straight and level flight with 100-120> >> knts. Then push the collective down. [...] ^^^ > > That's "translational lift".> No. Translational list is an additional lift component related to> helicopter speed against the air and will start at about 12 to 20 knts Pardon? You spoke about 100-120 knots. I said it's translational lift.You disgree because translational lift starts with 12 to 20 knots?!?Doesn't make the least sense.m.___ Flightgear-devel mailing listFlightgear-devel@lists.sourceforge.nethttps://lists.sourceforge.net/lists/listinfo/flightgear-devel ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
* Georg Vollnhals -- Wednesday 14 June 2006 11:57: > Melchior FRANZ schrieb: > > * Georg Vollnhals -- Wednesday 14 June 2006 03:02: > >> Take the BO105 and goo for a straight and level flight with 100-120 > >> knts. Then push the collective down. [...] ^^^ > > That's "translational lift". > No. Translational list is an additional lift component related to > helicopter speed against the air and will start at about 12 to 20 knts Pardon? You spoke about 100-120 knots. I said it's translational lift. You disgree because translational lift starts with 12 to 20 knots?!? Doesn't make the least sense. m. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Melchior FRANZ schrieb: > * Georg Vollnhals -- Wednesday 14 June 2006 03:02: >> Take the BO105 and goo for a straight and level flight with 100-120 >> knts. Then push the collective down. [...] >> Try it with the BO105 - see what happens? >> You are not only able to hold height with pulling the stick back but to >> climb with up to 1500 ft/min until speed is low. > > That's "translational lift". You know, the thing people are claiming > isn't implemented. :-} It's not realistic (as Maik himself says), No. Translational list is an additional lift component related to helicopter speed against the air and will start at about 12 to 20 knts (depending on type of helo). This is a real big addition lift component together with (an unwished) roll and yaw component. > but I'm not sure about the "dropping like a stone" thing. Normally, > people compare a fully loaded real helicopter (because they are sitting > in them as passengers together with several other people) with an > unloaded sim helicopter. Put more weight into the bo, and it sinks > faster, as one would expect in RL. > > m. "falling like a stone" might be the wrong expression but was told me by a RL pilot and demonstrated afterwards in a "hot" autorotation for a short time from 2000 to 1000 ft. It is pretty impressive and the vertical speed naturally depends on the type and configuration (ie weight) of the helo that you fly, our BK117 should come up to more than 2000 ft/min, a BO105 will be have some other numbers but generally comparable. You understand what one is doing when reducing collective? You reduce the common blade-pitch angle to (nearly) zero (depending on the type of helo you are flying). Of course, going into a heavy flare will give you some lift for a short time until your horizontal kinetic energy (speed) is reduced. But when I asked one of our experienced RL pilots about this scenario and what would happen, he told me that he could (if ever) hold altitude for a *very* short time by pitching back but could not make the bird ascend remarkably (what our FG helo does). OK, after all I want to say once again that I am not the real expert for this, we should have an *experienced RL helo pilot* who is also interested in flightsims to tell us what he thinks in general and detail about our FDM. But as I was very keen to learn all about helicopter flight behaviour and technics and comparing different helo sim flightmodels by checking the opinion of RL helo pilots I *just want to share* all I know with you. People simply should be advised that there are very diffent views regarding the actual helo FDM. I would feel pretty bad if we announce our helo FDM as "realistic" as we have some nice fixed wing aircraft with "real life pilots and a/c owners" approved flightdynamics, this would be bad for FG in common. Just my 2c, this discussion will probably never end :-) Regards Georg EDDW ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
* Georg Vollnhals -- Wednesday 14 June 2006 03:02: > Take the BO105 and goo for a straight and level flight with 100-120 > knts. Then push the collective down. [...] > Try it with the BO105 - see what happens? > You are not only able to hold height with pulling the stick back but to > climb with up to 1500 ft/min until speed is low. That's "translational lift". You know, the thing people are claiming isn't implemented. :-} It's not realistic (as Maik himself says), but I'm not sure about the "dropping like a stone" thing. Normally, people compare a fully loaded real helicopter (because they are sitting in them as passengers together with several other people) with an unloaded sim helicopter. Put more weight into the bo, and it sinks faster, as one would expect in RL. m. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Martin Spott schrieb: > > I don't claim the helicopter FDM in FlightGear is perfect, but turning > it down just because a few details are missing, whereas most of the > actual in-flight behaviour is pretty well done, is unjustified, > .. .. > Usually it _is_ my intention to stay within aircraft limits. It seems > we see different goals in the FlightGear helicopter simulation: > > I want to see a simulation of what is supposed to happen during a > flight and I'm quite satisfied for now. Apparently you want to see a > simulation of what is _not_ supposed to happen during a flight, so your > expecations and your valuation of what's already there differs > significantly. > > Sometimes things are _so_ simple :-) > Martin. Well, Martin, sometime things are *not* so simple as the seem to be :-) I did not want to go into this discussion to prevent a further flamewar but as you obviously are insisting on your wrong opinion I have to say some words to back Josh: I like the FG BO105 very much and do a lot of sim-flights with the helo, of course equipped with some sufficient precise controls (pedals, sep. collective,stick). But we have only a FDM derivative from fixed wing FDM and the helicopter sometimes behaves like that. You can't train somehow realistic procedures. These are not "a few details" it is the whole thing itself what is unrealistic when you want it as a *simulation*. True, it gives some very nice general helicopter feeling taking it as a *game*, especially hovering and low speed maneuvers - and this is why I like to fly the BO105, though, and this is why especially newcomers can learn basic aspects of vertical flight, *playing* with it. If you speak over a somehow realistic helo FDM in a *simulation* it is a *must* to have autorotation capability, at least ground effect for the rotor-disk at a whole (is more complicated in reality), translational lift, vortex-ring-state and a at least simple model of air-downwash reaction to helicopter body, I won't think here of refined stuff (ie interaction of rotor-downwash and tail-rotor). You also should have some realistic instrument readings regarding rotor RPM and engines (ie. to have the splitting needles when autorotating). But most annoying are the *normal* inflight effects where the helo behaves more like a wing aquipped a/c (sample below at the bottom). Ok, you are right saying that I am *no* helicopter pilot and might be wrong. But under blind man that one who has at least some visus on one eye migh be the king: I am flying a R/C helicopter, have the chance to discuss all that stuff regarding real flight procedures/behaviour versus simulated behaviour with real life pilots - which I did very often over the last years as I am regularly flying as a crew member many hours a week. I worked through a lot of helicopter training books the last years . I have been flying a lot of hours with FLY!II and X-Plane helos a followed what real-life turbine and piston helo pilots said about the weak points of these FDMS. So after all, I at least have some clue how to check the validity of a helicopter *simulation*. Only one *very simple* example which everybody can test himself: Take the BO105 and goo for a straight and level flight with 100-120 knts. Then push the collective down. A real helicopter is immediately in a "hot" autorotation state. It simply nearly "falls down" from heaven without collective pitch set at a vertical speedrate of ie 2500 ft/min. You can't hold it in straight and level flight for a relevant time even with the cyclic stick full back. Try it with the BO105 - see what happens? You are not only able to hold height with pulling the stick back but to climb with up to 1500 ft/min until speed is low. *This* is how I would expect a fixed wing to behave after reducing throttle because you reduce power but have the lift of the wings. A helicopter simply has only very small lift at the blades when reducing blade pitch although the engine(s) is/are running and rotor RPM is constant. This is not only important for a "hot" autorotation (described here) but for normal descend procedures. Due to the "fixed wing behaviour" you have to fly *some* circles to reduce speed and height with the FG BO105 when at some altitude with higher speed whereas in reality you would reduce the collective and when turning to reduce speed you are already going down pretty soon. Another example are the nearly *lacking* torque forces when increasing/decreasing collective - you might only recognize this when using pedals (of course with --disable-auto-coordination). And the unsufficient tail-rotor power ... and .. After all, I don't want to make all bad. We just have to be honest that we don't have an acceptable standard for helicopter-flight at the moment in FG despite all that wonderful work Maik Justus did for all FG helicopter fans and the very nice 3D-model of the BO105 thanks to Melchior Franz. But at the moment,
Re: [Flightgear-devel] UAV Heli and Matlab
Martin Spott wrote: > I want to see a simulation of what is supposed to happen during a > flight and I'm quite satisfied for now. Apparently you want to see a > simulation of what is _not_ supposed to happen during a flight, so your > expecations and your valuation of what's already there differs > significantly. More like a simulation of what happens no matter what the pilot does. "Supposed to" is a relative term. I guess I *am* more demanding though. And to be fair, practicing autorotation is something that all helo pilots should do at some point. There is also such a thing as an aerobatic helicopter routine. While I'm sure they don't put the rotor RPM in the red, I would not be surprised if they routinely put it at the bottom of the green or even into the yellow. If you're not using all the horsepower, your not putting on the best possible show. Josh ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Josh Babcock wrote: > Martin Spott wrote: >> This is what nowadays is done even on many model helicopters: They >> spool up the whole thing, activate the governor, which typically part >> of a FADEC in large helicopters, and have the rotor running at fixed >> speed for the whole trip. > Assuming that you stay withing the helicopter's capabilities. Usually it _is_ my intention to stay within aircraft limits. It seems we see different goals in the FlightGear helicopter simulation: I want to see a simulation of what is supposed to happen during a flight and I'm quite satisfied for now. Apparently you want to see a simulation of what is _not_ supposed to happen during a flight, so your expecations and your valuation of what's already there differs significantly. Sometimes things are _so_ simple :-) Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Martin Spott wrote: > Josh Babcock wrote: > >> For instance: translational lift, ground effect, retreating blade stall, >> and VRS. I don't think that there is any kind of realism regarding the >> energy model for the blades. (AFAIK, all they do is spool up to the >> specified rpm when the engines are turned on and then back down again >> when they turn off) > > This is what nowadays is done even on many model helicopters: They > spool up the whole thing, activate the governor, which typically part > of a FADEC in large helicopters, and have the rotor running at fixed > speed for the whole trip. Assuming that you stay withing the helicopter's capabilities. Go outside though, and the engines max out and RPM starts to drop. (assuming that the torque limit is higher than the max engine output). And someday I want to model a helo without a governor. They did exist, I have enough control axis' to do it, and I don't think it's ever been done. I'd even write some Nasal code to run the throttle in a sloppy human-ish way for people who don't have the extra control axis :) > Regarding retreating blade stall, at least there's an effect that comes > close when you cruise at high speed. I _do_ agree that the BO is able > to reach much higher speed than I'd expect from the real helicopter Personally, I have never noticed this, even though I have had the bo up to several hundred kts. I'll take your word for it but it is definitely broken, if not missing. > > I don't claim the helicopter FDM in FlightGear is perfect, but turning > it down just because a few details are missing, whereas most of the > actual in-flight behaviour is pretty well done, is unjustified, > I'm not turning it down, in fact I designing a new helo for FG right now. (ch53e, anyone want to help with the FDM?) All I said was that it's not the best out there, and I stand by that. I just want to try and get some attention in this area. I'm really not a programmer, all I can do is cheer and make models. http://jrbabcock.home.comcast.net/flightgear/ch53e/progress/progress.html Josh ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Melchior FRANZ wrote: instance: translational lift, [...] > > Translational lift is implelemented. According to Maik it's just not > realistic yet. > > > http://baron.flightgear.org/pipermail/flightgear-devel/2003-October/021940.html > > I also think that the helicopter FDM *parts* aren't bad. Just not finished, > and not well integrated in YASim. It's just constant speed rotors without > engines, and not really a "helicopter FDM" at all. I stand corrected. Josh ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
* Josh Babcock -- Tuesday 13 June 2006 04:33: > I also feel, however, that there are some important things > missing from the FDM. > > For instance: translational lift, [...] Translational lift is implelemented. According to Maik it's just not realistic yet. http://baron.flightgear.org/pipermail/flightgear-devel/2003-October/021940.html I also think that the helicopter FDM *parts* aren't bad. Just not finished, and not well integrated in YASim. It's just constant speed rotors without engines, and not really a "helicopter FDM" at all. m. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Josh Babcock wrote: > For instance: translational lift, ground effect, retreating blade stall, > and VRS. I don't think that there is any kind of realism regarding the > energy model for the blades. (AFAIK, all they do is spool up to the > specified rpm when the engines are turned on and then back down again > when they turn off) This is what nowadays is done even on many model helicopters: They spool up the whole thing, activate the governor, which typically part of a FADEC in large helicopters, and have the rotor running at fixed speed for the whole trip. Regarding retreating blade stall, at least there's an effect that comes close when you cruise at high speed. I _do_ agree that the BO is able to reach much higher speed than I'd expect from the real helicopter I don't claim the helicopter FDM in FlightGear is perfect, but turning it down just because a few details are missing, whereas most of the actual in-flight behaviour is pretty well done, is unjustified, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Martin Spott wrote: > "Correu PelDavid" wrote: > >> Isn't the FDM much good? >> I thought it would be. What fidelity lacks? > > I find the helicopter FDM quite reasonable. I've been flying a model > helicopter about the time when I finished school but this is > already 20 years ago, so my memory might play tricks with me. Still the > BO-105 behaves very much as how I'd expect it from knowledge of the > aerodynamical effects. > > In my opinion the biggest drawback is the lack of appropriate > helicopter controls. A joystick and pedals for 200 Euro each will never > replace a real stick, collective and pedals. Successfull helicopter > flight is achieved by small and highly precise movement of all the > controls you have in such a beast - and I've personally never met > simulator controls that really meet the requirements. > > Cheers, > Martin. Though I have never flown a helo, I have a friend who has and I agree with you on the lack of good controls. Also, don't get me wrong, I think that YASim is a good helo sim, though not as good as X-Plane in many respects. I also feel, however, that there are some important things missing from the FDM. For instance: translational lift, ground effect, retreating blade stall, and VRS. I don't think that there is any kind of realism regarding the energy model for the blades. (AFAIK, all they do is spool up to the specified rpm when the engines are turned on and then back down again when they turn off) There's no coupling at all between blade energy and vertical acceleration and speed. You can't affect rotor or engine RPM with the collective at all. Try autorotating some time. Other less important missing features include: effect of rotor wash on other rotors and wings export of data regarding rotor disc coning and orientation (for animations) support for multiple engines support for engine throttles (PCLs, FADECs or manual throttles) Josh ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
"Correu PelDavid" wrote: > Isn't the FDM much good? > I thought it would be. What fidelity lacks? I find the helicopter FDM quite reasonable. I've been flying a model helicopter about the time when I finished school but this is already 20 years ago, so my memory might play tricks with me. Still the BO-105 behaves very much as how I'd expect it from knowledge of the aerodynamical effects. In my opinion the biggest drawback is the lack of appropriate helicopter controls. A joystick and pedals for 200 Euro each will never replace a real stick, collective and pedals. Successfull helicopter flight is achieved by small and highly precise movement of all the controls you have in such a beast - and I've personally never met simulator controls that really meet the requirements. Cheers, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
On Tue, 13 Jun 2006 07:51:46 +1200, dene wrote in message <[EMAIL PROTECTED]>: > I agree and that's why I still fly helicopters even though I > can't even follow Rule #5. That's the nice thing about a Sim... > crashes don't hurt :-) ...the bad habits might, mightily too. ;o) -- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
> Question #4: Has anybody tried the Matlab-FlightGear connection without > perishing on the try? If so, is there any documentation? > I don't know if there is any documentation. I kind of remember that Jon had asked someone to come up with a paper or something... but there is ofcourse the protocol documentation you can find with flightgear to find out what the udp packets look like. There also is a small toolbox you can download from the mathworks website which will help in sending and reading udp data in simulink. You can find that here http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=345 best of luck!! ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Isn't the FDM much good? I thought it would be. What fidelity lacks?Does anybody pilot R/C helicopters to compare?What is the best FDM in FG for helis?And about the 5th rule... We ought to share a multiplayer sessions someday and take a look at the hover capabilities of the helis users. David2006/6/12, dene maxwell <[EMAIL PROTECTED]>: >"dene maxwell" wrote:>> > Rule #5 Until you can hover indefinitely over the same point on the>ground> > and and climb and descend without moving from that point, don't try >anything> > fancier...ie practice hovering.> > Rule #6 When you can hover, practice pulling up from level flight to a> > stationary hover.>>I don't agree. It's still much fun slowly flying around known terrain >in the helicopter even if you're not a skilled helicopter pilot - you>just won't manage to land the beast without crashing :-)>>Martin.>--I agree and that's why I still fly helicopters even though I can't even follow Rule #5. That's the nice thing about a Sim... crashes don't hurt :-):-D ene_Discover fun and games at @ http://xtramsn.co.nz/kids___Flightgear-devel mailing listFlightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
>"dene maxwell" wrote: > > > Rule #5 Until you can hover indefinitely over the same point on the >ground > > and and climb and descend without moving from that point, don't try >anything > > fancier...ie practice hovering. > > Rule #6 When you can hover, practice pulling up from level flight to a > > stationary hover. > >I don't agree. It's still much fun slowly flying around known terrain >in the helicopter even if you're not a skilled helicopter pilot - you >just won't manage to land the beast without crashing :-) > >Martin. >-- I agree and that's why I still fly helicopters even though I can't even follow Rule #5. That's the nice thing about a Sim... crashes don't hurt :-) :-D ene _ Discover fun and games at @ http://xtramsn.co.nz/kids ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
"dene maxwell" wrote: > Rule #5 Until you can hover indefinitely over the same point on the ground > and and climb and descend without moving from that point, don't try anything > fancier...ie practice hovering. > Rule #6 When you can hover, practice pulling up from level flight to a > stationary hover. I don't agree. It's still much fun slowly flying around known terrain in the helicopter even if you're not a skilled helicopter pilot - you just won't manage to land the beast without crashing :-) Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Correu PelDavid wrote: > Hello, > > After lots of exams, and almost infinite tasks at university, and before > some more to come, I'd like to ask for a few things I'd like to do in > the quiet sunny summer days. > > I'd like to mix FlightGear with Matlab through the aerospace toolbox. > Weeks ago I asked for the 0.9.8a versions, which was kindly linked so I > could download, but I could work on it, and I have some questions. > > So, Question #1: To practice with the helicopter, what key do I have to > press to activate the engine? I've tried anything I found on the help > without success. > Question #2: How can I setup the joystick? I'd like to exchange some of > the axis function. > Question #3: Does anybody have a 3D model for a R/C-like helicopter? > Something like a 1 meter thing. > Question #4: Has anybody tried the Matlab-FlightGear connection without > perishing on the try? If so, is there any documentation? > > Your 'question #1' might be: Is that fool a newbee? > My answer: absolutely. > > Thanks for your help. Any advice will be gratefully accepted. > > David > > > > > ___ > Flightgear-devel mailing list > Flightgear-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/flightgear-devel The helicopter simulation that YASim does is very primitive. Really the only working model is of the bo105, and is suffers from the lack of fidelity in the FDM. Josh ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] UAV Heli and Matlab
Hi >Hello, > >After lots of exams, and almost infinite tasks at university, and before >some more to come, I'd like to ask for a few things I'd like to do in the >quiet sunny summer days. > >I'd like to mix FlightGear with Matlab through the aerospace toolbox. >Weeks ago I asked for the 0.9.8a versions, which was kindly linked so I >could download, but I could work on it, and I have some questions. > >So, Question #1: To practice with the helicopter, what key do I have to >press to activate the engine? I've tried anything I found on the help >without success. What helicopter are you using? my experience with a helicopter (Bo105 Rule #1 Turn autocoordination OFF Rule #2 see rule #1 ;-) Rule #3 The throttle works reverse to fixed wing aircraft. Rule #4 Using the keyboard rudder (tail rotor) control is almost impossible. Rule #5 Until you can hover indefinitely over the same point on the ground and and climb and descend without moving from that point, don't try anything fancier...ie practice hovering. Rule #6 When you can hover, practice pulling up from level flight to a stationary hover. Rule #7 When you can hover and pull up to a hover with 100% success try other things. >Question #2: How can I setup the joystick? I'd like to exchange some of the >axis function. See above rules .. they may help >Question #3: Does anybody have a 3D model for a R/C-like helicopter? >Something like a 1 meter thing. >Question #4: Has anybody tried the Matlab-FlightGear connection without >perishing on the try? If so, is there any documentation? > >Your 'question #1' might be: Is that fool a newbee? >My answer: absolutely. > >Thanks for your help. Any advice will be gratefully accepted. > >David :-D ene >___ >Flightgear-devel mailing list >Flightgear-devel@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/flightgear-devel _ Looking for love? Check out XtraMSN Personals http://xtramsn.match.com/match/mt.cfm?pg=channel&tcid=200731 ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] UAV Heli and Matlab
Hello,After lots of exams, and almost infinite tasks at university, and before some more to come, I'd like to ask for a few things I'd like to do in the quiet sunny summer days.I'd like to mix FlightGear with Matlab through the aerospace toolbox. Weeks ago I asked for the 0.9.8a versions, which was kindly linked so I could download, but I could work on it, and I have some questions.So, Question #1: To practice with the helicopter, what key do I have to press to activate the engine? I've tried anything I found on the help without success. Question #2: How can I setup the joystick? I'd like to exchange some of the axis function.Question #3: Does anybody have a 3D model for a R/C-like helicopter? Something like a 1 meter thing. Question #4: Has anybody tried the Matlab-FlightGear connection without perishing on the try? If so, is there any documentation? Your 'question #1' might be: Is that fool a newbee?My answer: absolutely.Thanks for your help. Any advice will be gratefully accepted.David ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
