Question IMFD Escape Vector and TransX Eject Plan

[alef]

Hi,

I was comparing a same flight plan (Earth to Mercury) using the two MFDs.

I'm confused on how to map IMFD Escape Vector's oV/Iv/PlC from the Target Intercept program to the Tranx's Ch.Plane/Prograde/Outward velocities from the Eject Plan.

PlC should coincide with Ch.Plane, oV seems to be the Prograde, even if IMFD manual says it's "outward delta velocity". What the IMFD iV means? Manual says "inward delta velocity".

Thanks,
alef

 

[dgatsoulis]

The first thing to remember is that those two MFDs use different methods to solve the same problem, so the numbers that you get from one don't match the other exactly.

With that in mind, here is how the numbers from the Eject plan from TransX and the Target Intercept program from IMFD relate to each other:

[math] (TransX) \sqrt{Progr.^2 + Pl.Ch.^2 + Outw.^2} = oV (IMFD)[/math]
[math] (TransX) Enc.V. = iV (IMFD)[/math]

 

[Tommy]

IMFD's designations can be confusing - since they change meaning depending on the page.

oV does stand for outward velocity - but in the sense that increasing your prograde velocity increases your altitude. In Target Intercept, this does consider the velocity of the source body, but not the velocity of the vessel in orbit.

iV is more confusing. In set-up view, this refers to "inherent velocity" and is the relative velocity you will have with your target when you encounter it (can be used to estimate insertion dV).

In Burn View, iV means "inward velocity" and means velocity that is directed toward the source body. Depending on the mode, this "direction" changes. In "velocity mode" this is a vector that is at right angles to the ships velocity vector and is generally toward the source. In P-30 mode, this vector is directly toward the center of mass of the source.