RE: [Flightgear-devel]Re:[Flightgear-cvslogs]CVS:data/Aircraft/pa28-161
Jim Wilson wrote Vivian Meazza [EMAIL PROTECTED] said: Josh Babcock Vivian Meazza wrote: I enter the loop in a shallow dive, 2nd stage boost on, 350 kts, pull baaack the stick and the model rolls violently and does not enter the loop ... Works fine in other models so it's not the obvious - the joystick. But I expect I'm doing something wrong. Yup. Specifically, you are doing a snap roll. If you can keep the the AOA down, the plane won't stall and go into a snap roll. You could also try adding some flaps, but I'm not sure if that would bleed off too much energy. Best to just make the loop bigger. Remember, pull back a little, and the plane goes up. Pull back a lot, and the plane goes down ... fast. Thanks for the advice. It's not easy without Pilot's Notes specifying some entry conditions. I was guessing 350 kts I was probably pulling back too hard, difficult to remember. Too slow, and the model falls off the top, of course. Back to the Hunter - it's much easier - but I designed it that way, and it flew that way too :-). It sure is fun doing those, I just tried it for the first time in a while on the p51. You want to get up in the air (4500-5000ft agl). Manfold pressure should be in the 50-55 range, and prop pitch at max rpm. Go into a nice dive and pull back in the low 2000ft range. Once you get it the aircraft going good you can actually pull back pretty hard...and you can do multiple loops if your pilot has the stomach. You'll stall it quicker if you do a large loop, it gives gravity too much time to bleed off your momentum. Flaps will increase drag and not really help much with those stalls. The FDM is probably a little off. Andy just made a prop gearing change to YASim a couple weeks ago that should be useful in making the P51-D more accurate with a little tinkering. Still can't do it. Could the prop pitch be the problem - I can't find any method of controlling it - could you give me a hint (other than RTM :-)) Thanks for you help Vivian Meazza ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel]Re:[Flightgear-cvslogs]CVS:data/Aircraft/pa28-161
* Vivian Meazza -- Friday 13 February 2004 13:19: Could the prop pitch be the problem Unlikely -- it's already maximum by default. - I can't find any method of controlling it Either via http/telnet/property browser: /controls/engines/engine[n]/propeller-pitch Some joystick configs support it. And finally, you can add a key definition to you personal config, e.g.: key n=113 nameq/name descDecrease prop pitch./desc binding commandnasal/command scriptcontrols.adjPropeller(-1)/script /binding /key key n=81 nameQ/name descIncrease prop pitch./desc binding commandnasal/command scriptcontrols.adjPropeller(1)/script /binding /key m. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: [Flightgear-cvslogs] CVS:data/Aircraft/pa28-161
Vivian Meazza [EMAIL PROTECTED] said: Martin wrote: David Megginson [EMAIL PROTECTED] wrote: Update of /var/cvs/FlightGear-0.9/data/Aircraft/pa28-161 In directory baron:/tmp/cvs-serv12589 Modified Files: pa28-161-yasim-set.xml Log Message: Change camera position so that model doesn't rotate around the nose. I can't withstand the impression that changing the _camera_ position didn't lead to the intended success. Take a simple stick and rotate it around one of its ends. For an observer the phenomenon is still the same even when he changes his viewpoint. If you want to rotate the stick around its middle you really have to change the centre of rotation which means, that one end of the stick goes up and the other end goes down. At least in the _outside_ views the PA-28 still rotates around its nose after the recent changes, We've been here before haven't we? In developing the Hunter model I first put the model origin at the nose to conform to the YASIM origin, but the model then rotated about the nose - most disconcerting in outside views! I moved the model (not the YASIM) origin to the CofG - the model behaves nicely in all views. It's not strictly correct on the ground, because the model has differential braking, and should more or less rotate around the braked wheel, but you would have to have a very sharp eye to spot the deliberate :-) mistake. If you put the model back to the nose and use the method that the p51d and the pa28-161 use (the target offset) you'll look better on the ground. Best, Jim ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
RE: [Flightgear-devel] Re: [Flightgear-cvslogs]CVS:data/Aircraft/pa28-161
Jim Wilson wrote Vivian Meazza [EMAIL PROTECTED] said: Martin wrote: David Megginson [EMAIL PROTECTED] wrote: Update of /var/cvs/FlightGear-0.9/data/Aircraft/pa28-161 In directory baron:/tmp/cvs-serv12589 Modified Files: pa28-161-yasim-set.xml Log Message: Change camera position so that model doesn't rotate around the nose. I can't withstand the impression that changing the _camera_ position didn't lead to the intended success. Take a simple stick and rotate it around one of its ends. For an observer the phenomenon is still the same even when he changes his viewpoint. If you want to rotate the stick around its middle you really have to change the centre of rotation which means, that one end of the stick goes up and the other end goes down. At least in the _outside_ views the PA-28 still rotates around its nose after the recent changes, We've been here before haven't we? In developing the Hunter model I first put the model origin at the nose to conform to the YASIM origin, but the model then rotated about the nose - most disconcerting in outside views! I moved the model (not the YASIM) origin to the CofG - the model behaves nicely in all views. It's not strictly correct on the ground, because the model has differential braking, and should more or less rotate around the braked wheel, but you would have to have a very sharp eye to spot the deliberate :-) mistake. If you put the model back to the nose and use the method that the p51d and the pa28-161 use (the target offset) you'll look better on the ground. Tried that. Looks just the same to me. As I said some time ago: yer pays yer money and yer takes yer choice. Neither is right on the ground for differential braking: with one brake full on the aircraft more or less rotates around that wheel. The model doesn't! When the aircraft is moving the forward the CofG should rotate about some point outboard of the braked wheel. All to do with tyre slip angles, but I'm not sure if the FDM's know about those, and I would need to consult my race engineering handbooks. But, hey, we're building flight simulator, not a ground handling simulator. If it's good enough that'll do me. PS why in an external view does the Hunter appear to do an upward roll in the up leg of a loop. And a downward roll in the down leg? And why can't I loop the P51? PPS the B52 rolls very nicely. Of course the real wings might fall off. Not sure I'd like to go to war in an aircraft whose wings fall off. Curiously confused Vivian Meazza ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
RE: [Flightgear-devel] Re:[Flightgear-cvslogs]CVS:data/Aircraft/pa28-161
Jim Wilson added Vivian Meazza [EMAIL PROTECTED] said: Tried that. Looks just the same to me. As I said some time ago: yer pays yer money and yer takes yer choice. Neither is right on the ground for differential braking: with one brake full on the aircraft more or less rotates around that wheel. The model doesn't! When the aircraft is moving the forward the CofG should rotate about some point outboard of the braked wheel. All to do with tyre slip angles, but I'm not sure if the FDM's know about those, and I would need to consult my race engineering handbooks. But, hey, we're building flight simulator, not a ground handling simulator. If it's good enough that'll do me. The ground handling is all part of it. I'm not sure what you are seeing...but if you moved the origin then the aircraft should have at least moved the same amount. It might look the same but look closer. Are the wheels in the same spot on startup? Basically with you need to make sure the gear is in the right spot, etc, etc. I moved the origin, then applied an equal and opposite offset. When one differential brake is applied and the model is viewed in or helicopter view tower view it appears to be turning around its axis rather than around the braked wheel. That said, in chase view and in chase view wo (without) yaw it looks good. This is seems to be the case if the model origin is either the nose (and with offset) or with the CofG as the origin. Am I seeing some artefact of the view perhaps? Seem just fine in cockpit view however. With YASim fdm configs you can configure gear animation so that when it compresses in yasim the gear compresses visually too. YASim will drop the altitude by an amount relevant to the modeled gear compression so the aircraft will drop, but the wheels will go through the pavement if you don't amimate the compression in the 3D model. Been there done that, no probs. PS why in an external view does the Hunter appear to do an upward roll in the up leg of a loop. And a downward roll in the down leg? And why can't I loop the P51? I'm not sure what you mean. but there is no problem looping the p51d. I've done it many times. You might need to hit ctrl+b to get the manifold pressure up to second stage level. Am I understanding your question? I enter the loop in a shallow dive, 2nd stage boost on, 350 kts, pull baaack the stick and the model rolls violently and does not enter the loop ... Works fine in other models so it's not the obvious - the joystick. But I expect I'm doing something wrong. PPS the B52 rolls very nicely. Of course the real wings might fall off. Not sure I'd like to go to war in an aircraft whose wings fall off. I'm not sure I'd like to go to war in an aircraft whose wings did not fall off either. No...wait...I'm sure. I wouldn't. Hah! No sense of adventure. Spinning around Vivian Meazza ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re:[Flightgear-cvslogs]CVS:data/Aircraft/pa28-161
Vivian Meazza wrote: I enter the loop in a shallow dive, 2nd stage boost on, 350 kts, pull baaack the stick and the model rolls violently and does not enter the loop ... Works fine in other models so it's not the obvious - the joystick. But I expect I'm doing something wrong. Yup. Specifically, you are doing a snap roll. If you can keep the the AOA down, the plane won't stall and go into a snap roll. You could also try adding some flaps, but I'm not sure if that would bleed off too much energy. Best to just make the loop bigger. Remember, pull back a little, and the plane goes up. Pull back a lot, and the plane goes down ... fast. Josh ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
RE: [Flightgear-devel]Re:[Flightgear-cvslogs]CVS:data/Aircraft/pa28-161
Jim Wilson asked Vivian Meazza [EMAIL PROTECTED] said: I moved the origin, then applied an equal and opposite offset. When one differential brake is applied and the model is viewed in or helicopter view tower view it appears to be turning around its axis rather than around the braked wheel. That said, in chase view and in chase view wo (without) yaw it looks good. This is seems to be the case if the model origin is either the nose (and with offset) or with the CofG as the origin. Am I seeing some artefact of the view perhaps? Seem just fine in cockpit view however. Hmmm...I'm not sure about that. It sounds like it is a view problem. Can you post your latest files so I can take a look after I get home from work? Delighted to that Jim, but how does that help, and how do I do it. Sorry to be dull. I'd really like to be able to show you a video ... Vivian ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
RE: [Flightgear-devel] Re:[Flightgear-cvslogs]CVS:data/Aircraft/pa28-161
Josh Babcock Vivian Meazza wrote: I enter the loop in a shallow dive, 2nd stage boost on, 350 kts, pull baaack the stick and the model rolls violently and does not enter the loop ... Works fine in other models so it's not the obvious - the joystick. But I expect I'm doing something wrong. Yup. Specifically, you are doing a snap roll. If you can keep the the AOA down, the plane won't stall and go into a snap roll. You could also try adding some flaps, but I'm not sure if that would bleed off too much energy. Best to just make the loop bigger. Remember, pull back a little, and the plane goes up. Pull back a lot, and the plane goes down ... fast. Thanks for the advice. It's not easy without Pilot's Notes specifying some entry conditions. I was guessing 350 kts I was probably pulling back too hard, difficult to remember. Too slow, and the model falls off the top, of course. Back to the Hunter - it's much easier - but I designed it that way, and it flew that way too :-). ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
