IMFD AppF Do Dont

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IMFD Appendix E: Navigation Maneuver Checklists IMFD Manual Contents IMFD Appendix G: Playback In-flight Notes

IMFD Appendix F - Do's and Don't ever's of IMFD[edit]

The do‘s and don‘t ever‘s of IMFD.


  • Realize that IMFD will not always work as expected 100% of the time.
Unfortunately, this is the truth of incredibly complex pieces of software offered for free. However, Jarmonik knows what he is doing and IMFD is reliable 99.9% of the time. If it does not work, look back to this manual and see if you find something that explains the problem. If you cannot, Jarmonik, myself (markl316), Tommy, and countless others can help you on the forum.
  • When you first open a program and a delta velocity to match a target orbit is displayed, ALWAYS time warp until it hits a minimum, THEN hit autoburn.
There are several reasons for this. First, it is the most fuel-efficient way to do a burn. Second, most programs do not take gravity into account. This means that as you approach a planet from far away, the orbit begins to change drastically. So if you correct the burn too far away, the orbit will change drastically, requiring lots of fuel to correct.
  • In the above case, if you start to time warp and dV increases, IMMEDIATELY execute autoburn.
dV will not increase and then decrease, so in this case perform the burn as soon as possible.
  • Learn how to cope with huge ships. With large slow rotating ships (such as Deepstar or Vespucci), either turn down Autoburn Max Rate, or manually rotate the ship to the correct attitude using the Burn Vector View and THEN execute autoburn.
If your ship keeps rotating and never getting to the correct burn attitude (attitude thrusters keep firing and the ship keeps spinning like crazy) when you hit [AB] (ie the RCS thrusters provide a low angular acceleration—good examples are Vespucci and Deepstar) you might want to turn Autoburn Max Rate down. Or, you could open burn vector view, manually rotate towards the cross, then hit Autoburn.
  • Plan Ahead.
Open programs such as Base Approach and Slingshot WAY ahead of time. Then time warping slowly, keep an eye on dV. Slow and steady wins the race.
  • Watch the display screen of autoburn during the ENTIRE time autoburn is controlling your ship.
Sometimes, Autoburn will act crazy. This is just a fact of life, with a complex free piece of software. If in the middle of the burn Autoburn starts to spin your ship like crazy, hit the [AB] button to shut it off. Try time warping at 10x for about 6 seconds (one minute sim time) and try it again. If it still doesn‘t work, switch to Burn Vector view and make the burn manually.
  • Use Realtime mode for burns instead of Off-Axis if Off-Axis is giving you trouble, even if everybody tells you not to.
Realtime burn mode is slightly less fuel efficient than off-axis, and much more reliable. If Off-Axis mode is giving you grief, just use realtime and don‘t worry about it. You can do any burn in realtime and get to your target and have everything work perfectly.
  • Slow down time and watch your orbit match the target’s orbit when using Off-Axis mode.
Sometimes, when using Off-Axis mode, the Autoburn will not shut down the engines, and your orbit (green) will go right past the target orbit. If this happens, just turn off Autoburn, wait 30 seconds, then engage Autoburn again—IN REALTIME BURN MODE. If this fails, switch to Burn Vector View and do the burn manually.
  • When doing a long burn, first do it in Off-Axis mode, then let Autoburn finish, then switch to realtime burn mode and engage autoburn again.
This is to allow Autoburn to make your burn perfectly.
  • Engage Autoburn early.
Even if it says Time to burn 120000 seconds, it is better to engage it early then to miss your ejection point. Plus, if you do this, Autoburn will slow down time as you approach the point of burn, so you never have to worry about missing the burn point.

Don’t EVER…

  • Switch between Realtime and Off-Axis mode during the Autoburn
This may make Autoburn go haywire. If you must switch, first turn Autoburn off (hit the [AB] button), then make the switch to Realtime, then engage autoburn a second time.
  • Engage Autoburn at high time warps.
This can cause Autoburn crashed, IMFD crashes, and CTD‘s. ALWAYS switch to realtime before engaging Autoburn.
  • Engage Autoburn for one program, and while the burn for that program is running, switch to a different program.
If you do this, Autoburn will not shut off the engines. You will burn until you realize what is going on, run out of fuel, or crash. Leave a program open when its autoburn is running.
  • Switch between internal view and external view when Autoburn is running.
Results of this problem are very similar to the problem above—the engines don‘t shut down when you are in external mode.
  • Engage Autoburn AFTER TtB says 0.
This causes many weird autoburn symptoms, including aiming your ship towards earth and diving straight for the planet. It is strongly recommended to quicksave very often in case this happens to you.
  • Use scenario editor to go back in time.
Instead, quicksave often. Using scenario editor to go back in time will cause many weird malfunctions. Also, don‘t EVER use scenario editor to go forward in time with two exceptions—on long flights (Earth to Pluto) when you are in the cruise phase (out of Earth‘s SOI, ship is in a stable state), or when fast forwarding many years to a launch window. It is recommended that you adjust first the seconds, then minutes, then hours, then days, then months, then years. This "gradual onset" of time change can help IMFD not crash or malfunction.
IMFD Appendix E: Navigation Maneuver Checklists IMFD Manual Contents IMFD Appendix G: Playback In-flight Notes