On Fri, 17 Sep 2004 16:09:12 +0100, Vivian wrote in message <[EMAIL PROTECTED]>:
> Arnt Karlsen wrote: > > > Sent: Friday, September 17, 2004 10:03 AM > > To: FlightGear developers discussions > > Subject: Re: [Flightgear-devel] Problem with ballistic sub-model > > > > On Fri, 17 Sep 2004 07:56:42 +0100, Vivian wrote in message > > <[EMAIL PROTECTED]>: > > > > > Ampere K. Hardraade wrote > > > > > > > Sent: Thursday, September 16, 2004 7:12 PM > > > > To: FlightGear developers discussions > > > > Subject: Re: [Flightgear-devel] Problem with ballistic sub-model > > > > > > > > On September 16, 2004 01:08 pm, Vivian Meazza wrote: > > > > > > > > > > There are some other basic shortcomings as well: the submodel > > > > > doesn't inherit the parent accelerations, or the velocities > > > > > and accelerations due to roll, pitch and yaw. Only release > > > > > droptanks when flying straight and level > > > > ..uh, in the real world, this is possible if not permissible, with > > fun consequenses like one or more hard points releases jammed for > > at least a while etc. > > > > > > > > > > They shouldn't inherit accelerations. > > > > > > Quite right - they shouldn't. I was getting over enthusiastic > > > there, and forgetting my Newtonian physics. > > > > ..don't worry, there is also Murphy law physics. ;-) > > > > Right, back to Newton :-). I think I've solved the problem. Mixing > elevation up = positive with speed down = positive nearly made my > brain blow a fuse .. ;-) > I had to reverse a number of signs to get it right. I took the > opportunity to add roll to the submodel so that droptanks will come > off with the right orientation. I not yet added either the parent > rotational speed to the submodel, or yaw, so if you release droptanks > with significant roll rate or yaw angle on the aircraft the submodel > will not be quite right. Straight and level, or nearly so, is fine. ..precisely, we will need roll rate, yaw, yaw rate, pitch rate etc, but no accellerations except gravity, to get it right. ..also, when we get that far in the modelling; some divebombers had release rigging that threw some, say centerline bombs, clear of the propeller, adding to the fun we dream up here. ..also keep in mind most bombs are hung by more than one points, so the hardpoint mechanism and the flight conditions, attitude, rates etc, act together deciding which points release first, second etc on each bomb. ..this too, has a major impact on the initial ballistics, think bobbing bombs dropping from B-52's or B-17's, on dropping out of the bomb bay, some of this is sudden exposure to the airstream, some is "un-even" release, asymetric or whatever. > I've asked Erik to upload the modified files to CVS. It looks OK on > the Hunter, but perhaps Lee could give the revised submodel a good > test. -- ..med vennlig hilsen = with Kind Regards from Arnt... ;-) ...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 [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
