Well, it spends 10 seconds between 95 and 99 degrees out of a 70 second orbital burn, then it rapidly returns to very nearly 90 degrees in the next 10 seconds. It seems to be moving perigee above the atmosphere and giving a nice circular 215x215km orbit.On Tue, 7 Jan 2003, Ian Woollard wrote:...and then it's ballistic till it reaches orbital height and then it burns and turns until it actually burns *down* slightly at upto 99 degrees to the vertical (no don't ask me, it's probably circularising the orbit or something ;-) ).It's not uncommon for final stages to enter orbit thrusting slightly below horizontal... but getting much of the orbital velocity that way, after a substantial coast, seems odd.
Yes. I have a thrust to weight factor. I'm currently using 130:1 which is rather ambitious.Is your simulation including thrust/weight effects? (That is, the engines can be smaller and lighter with a longer burn.)
The program fiddles around with the mass of the engines, the mass of the fuel, a stage ratio, 9 epochs for angles and target 'airspeeds' (angles and speeds trigger off different distances from the launch point). I linearly interpolate between the angles and speed epochs and randomly jiggle the values around looking for something better than what I have.
I've got corrections for mach effects on drag, and some nozzle corrections for altitude (the nozzle corrections are very rough at present.) My atmospheric model is simple exponential drop off with a scale height of 6 odd kilometers- I tried a model that was supposedly NASAs and 'more accurate', but it seemed to give density that went up by a factor of 4 as my vehicle ascended, so I doubted that model, either that or the atmosphere is very weird.
Anyway, whole program needs to be taken with a ton of salt, like any simulation of just about anything.
Kinda fun though.
Henry Spencer [EMAIL PROTECTED]
