Earth to Venus IMFD

[Fly]

Lupin_Yonder;15733]

L set to Target Intercept
Ref=Sun
Source=Earth
Target=Venus
Two plane ( for lowest Ov )
Realtime option grayed out, cant change to off axis
Change TIn to lower Ov

L set to Orbit Eject
Set to course
Ref=Earth
Should mention at this point that EIn is 18.9 Deg
Attempt to change realtime to Off axis but it resets to realtime
Auto burn often stops short of finishing burn

P.S. Thanks again for your help guys, once a crack this, the systems my cold dark oyster

Well, I can see one thing right off the bat.

You are using the left mfd for both target intercept and Orbit eject. Your left mfd should be slaved to the right mfd (or vice versa). On the left should be the target intercept program. On the right should be the orbit eject program.

Your orbit eject program is using info from the target intercept for the ejection burn. Since you dont have them slaved to each other, your not getting the proper ejection burn time.

In other words, get rid of the map program. Its not needed for ejection burns. Use the target intercept in one mfd, and the orbit eject in another. Only after you have left the SOI of the planet should the map program be used.

Hope this helps. Ive been using IMFD with great success for many years now. Ive done trips to Saturn using multiple slings around Venus, one around Mars and a final sling around Jupiter. Once you get the hang of it, the sky is the limit .

 

[Zatnikitelman]

I think part of Lupin's problem is the fact that there's hardly any tutorial documentation for the 5.1x series of IMFD. I've tried IMFD, but can't seem to figure it out worth a flying flip. I can follow the Earth-Moon Free Return tutorial, but it's completely unintuitive beyond just the tutorial. There is simply no explanation of why you do what you do.
I've been asking occassionally for IMFD tutorials since version 5 came out, but no written tutorials have materialized. The video tutorial Europa to Callisto is great, but unless I want to take 20 mins worth of notes, it just doesn't work. I'm not trying to slight the creator of the wonderful vid, but I need a printable reference I can place in front of me on my desk.

 

[Lupin_Yonder]

I think part of Lupin's problem is the fact that there's hardly any tutorial documentation for the 5.1x series of IMFD. I've tried IMFD, but can't seem to figure it out worth a flying flip. I can follow the Earth-Moon Free Return tutorial, but it's completely unintuitive beyond just the tutorial. There is simply no explanation of why you do what you do.
I've been asking occassionally for IMFD tutorials since version 5 came out, but no written tutorials have materialized. The video tutorial Europa to Callisto is great, but unless I want to take 20 mins worth of notes, it just doesn't work. I'm not trying to slight the creator of the wonderful vid, but I need a printable reference I can place in front of me on my desk.

Thanks mate, you've hit the nail on the head. I also completed the free return and had exactley the same experiance, great vid but i had no clue what i was doing, i was just entering in arbitary figures into an unknown system. It looks like im not alone in my n00bness of IMFD, is there something really basic im missing??
P.S. Will try IMFD with orbit eject slaved to Target int, see if that helps

One last thing, i thought i should re-iterate what my main problem at the moment seems to be, with Orbit eject program, i cannot change the realtime veriable while doing two plane transfer and the burn stops way short of completion

 

[Dr Pepper]

Hi Lupin. I've used IMFD for quite some time, so I know what some things do (and dare I say) I have a grasp at why. I think.

So, let me go over a little teaching with you, so hopefully I can help out. I'm going to assume that, you have the latest version of IMFD, and judging by your earlier posts, you know at least the basic functions of the MFD (like what buttons like Trg do, ect). Also, this is being written under the impression that you are using the Deltaglider to get from the Earth to Venus (which you probably aren't, but you can use what you learned to create other flight plans with different aircraft). One more thing: As you know, IMFD can slave one MFD to another. Wether you use one MFD or two slaved ones is your own opinion. I prefer to use one MFD so I can use the other for things like the Orbit, Map, Surface, and the Align MFDs. Now, on to it...

Once everything is loaded, the first step is to open the Configuration page and set your time display to either GET or MJD (I prefer MJD). Pick one now, but I will use MJD for this.

Next, open up the Course program and select "Target Intercept." Set your target (Venus). The Course program displays six useful variables: TEj (Time to Eject), a left MJD/GET display (Your time/date of ejection), TIn (Time to intercept), a right MJD/GET display (your planned time/date of arrival), Prograde (opposite is Retrograde; is the direction you want to eject from), and Off-Plane (other settings are Source Plane, Two Plane, and Target Plane; this controls how you want to fly the transfer; It's usually best to select Off Plane, but this is not always the case). Alter the right MJD display to adjust your Delta-V readout, near the bottom of the screen, to reach a nice low point (or higher if you want, but a higher dV=Higher amount of fuel used). You can also alter the TEj variable, which will help if you are taking off from a planet and you do not want to eject immediatally. However, adjusting this typically has little effect on the dV readout.

Next, open up the Surface Launch program. Here, you will see a bunch of numbers, with three really important ones: EIn (The angle between your current plane and the Ejection plane), Time (countdown timer to take off time), and BLL (only when landed, displays the heading your should take off to). Basically, once the EIn gets near 0.00° (+ or - 0.5°-0.8°) and time is near zero, you should take off along the BLL heading and get to a parking orbit.

Once in orbit, open the Orbit Eject program. First thing to check is teh EIn readout. If it is within + or - 0.5° to 0.8° of zero, you can eject with little worry. If it is not, you need to open up the Align MFD and burn either Normal or Antinormal to reduce your EIn readout. There are a few variable to mess around with, but only one is needed. Swtich the "Realtime" variable to Off-Axis (also called Prograde in the older IMFD versions). You will now see a two purple lines extending from the planet center to the purple orbit (the orbit you need to achieve). This is your "burn area," as I like to call it. Now, you can either use the BV display to manually perform the burn, or you can have IMFD do it automagically with the "AB" button. Press it and pour a glass of your favorite drink. The burn will automatically commence. Also note that now would be a very good time to quicksave.

The burn will automatically begin, and soon it's off to the stars you go...

Once you've reached 0.5g on the Orbit MFD, the Orbit-Eject display will display a "Have a nice voyage!" message. Switch an MFD to the IMFD Map display. Now, select Venus as your target and the Src as yourself (which would default to the sun, but whatever). Press Dsp (display planets/orbits) and SoI (Spheres of influence). You will now see your orbital path hopefully somewhere near Venus. Open the course program you made earlier and, this is important, set the Src to yourself, not Earth. This is done so IMFD bases it's orbital maneuverNow if you want, tweak the arrival MJD for better (or worse) arrival conditions. Then autoburn again.

...More interplanetary flight...

About halfway to three-fourths of the way to the target, use the Course program's autoburn function again.

About two days from planetary intercept (which you can find out by subtracting the Time of Arrival MJD from your current MJD), open up the BaseApproach program. First, make sure the Src is set for self, otherwise it will try to set up an orbit around the sun. Next, change the variable "Re-entry" to "Orbit Insert(ion?)." Then, set the latitude (Lat) and longitude (Lon) variables to whatever you want, as well as the Oribtal Altitude (Alt). If you use the SET button for the Alt variable, make sure you add the "k" after the altitude (like 120.0k or 234.54k), otherwise you will probably end up with an orbital altitude of a few hundred meters rather than kilometers. Now autoburn. Autoburn again once you are about one-fourth of the way inside Venus' SoI (on the map program). Then once or twice more a little bit later.

Then, just perform a retrograde burn at your Perapsis (or Perigee or whatever you want to call it) and Insert into orbit. You may also want to try aerobraking by setting your Alt variable to the very upper atmosphere, as to aid in slowing down.

Now, I think IMFD can autoburn to an orbit insertion, but I'm not sure. Try it if you feel like it.

Welcome to Venus!



Hope I helped. Also, I looked over the list of what you did to set up the flight. Here are a few tips:

1) Make sure you are in a stable, free (undocked) orbit. Not being in one could cause you to be unable to select the Off-Axis function in the Orbit Eject page.

2) Make sure your orbit dosen't drift around (get out of the proper inclination) while waiting for the ejection burn. If it does, re-align.

3) On the rare occurance that you unexpectedly have a close encounter with a planet or a moon, you will need to perform another autoburn to get yourself on the correct trajectory once you leave the planet/moons SoI.