Kerbin -> Eve -> Kerbin trajectory?

[NFunky]

So I've got the old Explore Eve contract here.  I could have just packed a ton of fuel and done the whole 'go into orbit of Eve and wait for the return window' thing, but I decided I'd try to do it the hard way.  So here I am on a Hohman transfer to Eve, with aroun 900 m/s dV, and I'd like to get back to Kerbin in under 10 years if possible.

I guess what I'm really asking is how to properly set up an Aldrin cycler orbit with Eve and Kerbin?  I'd like to be able to fly-by Eve (near or far, doesn't matter) and return to hit the Kerbin atmosphere in as little time as possible.  Again, I have ~900 m/s for maneuvers, so there's a good amount of wiggle room here.

Has anyone done anything like this?  Any tips would be very much appreciated.

[CBase]

35 minutes ago, NFunky said:

So here I am on a Hohman transfer to Eve, with aroun 900 m/s dV

Actually you might want to go back to launch and plan first: Date and direction of first transfer make huge differences. 900 m/s is not a lot to play when changing interplanetary trajectories.

How about using

 

Just enter Kerbin -> Eve -> Kerbin, your start day, some dV limit from orbit and then let it search and sort for fastest solution. If you do an aerobrake for Kerbin, around 1100 m/s dV and 200 days travel time are possible.

Note the incliniation: Solutions are not always planar !

[NFunky]

Thank you guys for the advice.  I've used Flyby Finder for RSS before and it's great, but I kind of didn't want to use any external tools with Stock.  I do think that next time I try something like this, I'll definately work on my launch window.  I'm thinking transfer earlier and faster?

Anyway, I was able to get a return trajectory using about ~500 m/s in maneuvers.  Since it took me a lot of trial and error, and I learned a lot from the experience, I thought I'd include some pics too.  (I apologize for the links, the embed image function isn't working.)

First thing I want out of the Eve encounter is to sling my Sun Ap way up above Kervin's orbit.  By the time I leave Eve SOI, Kerbin is lagging really far behind and will only get further, so I need to slow way down to let it catch up.  I also need to make sure that my ascending or descending node is right where my orbit re-crosses Kerbin's.  Luckily,  it looks like I can do most of that with the gravity of Eve.

https://www.dropbox.com/s/crgxrdya9ry7zo8/screenshot1.jpg

Since my Eve flyby w`iop[,asn't able to raise my Sun Ap quite enough, I do a prograde burn at Eve Pe.  This, in theory will let me fine tune the timing of the intersect precisely enough to meet Kerbin when we cross.

https://www.dropbox.com/s/91soizs24fibw25/screenshot2.jpg

I say in theory cause I thought I would just be able to watch the "closest approach" distance while I burned, but the patched conics weren't having it.  It took many quicksaves and reloads to get this right, and here is a pic of what it looked like.  You can see it is saying 14 years, and it would sometimes get up into the thousands of years.  This was honestly my biggest frustration with this whole mission.

https://www.dropbox.com/s/r6mrjt5gqubcabd/screenshot3.jpg

It wasn't until after I had passed the first intersect with Kerbin's orbit that I got the true close approach numbers.  Does anyone know how to make the patched conics behave better for interplanetary stuff?

https://www.dropbox.com/s/028eop67k9ppypd/screenshot4.jpg

After this, it was just a matter of cruising to aphelion and doing some final minor normal/radial corrections to get an encounter.  And all in less than two years!

https://www.dropbox.com/s/wr71eo1hx8zqqfr/screenshot5.jpg

I sure learned a lot about orbital mechanics, and even more about the KSP predictive system.  I hope others find this an educational example too.