Request Better Arrive MFD

[RAF Blackace]

When manually landing on the Moon in AMSO, I can not get the thrust right to arrive at the base with zero acceleration, I either overshoot or end up short ( I use limited fuel as I like realism, so I have little margin for error). I have hunted for an MFD that may help but the closest seems to be Arrive MFD. This works fine for level flight but it does not help in AMSO in the LEM because the thrust is 90 degrees out of plane from what arrive expects. Also it expects to see main engine thrust and not hover.

I would think the cals are not that hard, all you need to do is read the speed and distance from the base and calculate the TOTAL deceleration G required to arrive at the target with 0 speed.

The accelerometer MFD already gives you a TOTAL G so those calcs are already done for actual G.

All you need to do is match calculated to actual and you should arrive at the base at 0 speed, providing your thrust is in the right direction of course.

I would like to know if anyone has, or knows of such an MFD. Or does anyone plan on making one in the future ?

I would do it myself if I knew how

Thanks.

 

[Tommy]

The latest Burntime Calculator MFD has some features that may help. First, you can choose which engines you will use, and if you use the dV function and enter in your current velocity, it will tell you how far you will travel before your velocity reaches zero. Note that you will likely be in an eccentric orbit with a low PeA, so you will accelerate a bit - I'd suggest waiting until you are 500k from target before entering the velocity, and "fudge" it a bit to reflect current ACC values.

 

[RAF Blackace]

I could pause the scenario and work it out on a calculator. I was hoping for something more dynamic and real time than just obtaining a snap shot figure. Although I do appreciate the pointer, I have not used BTC before so it may help.

 

[clickypens]

I know aerobrake doesn't work with places without atmosphere, but would reentry mfd? AFAIK, it's a graphical representation of where you, where you're going and how much deceleration you need to get there.

 

[Andy44]

Reentry MFD does indeed work over airless bodies. I have used it with lunar landing vehicles that brake and land using hover jets in the same manner as the Apollo LM did. When you pitch up and fire up the hoverjets, you adjust the throttle so that your actual decelleration matches the required.

As a general rule, though, if you are in low lunar orbit, start decelerating at half a G when you are 300 km from your landing site and you will get fairly close. You will have to practice to get really good at it.

 

[RAF Blackace]

Burn time calc does not help. It gives you data and assumes you are at 100% thrust which of course you are not always at when using the LEM hover engine.

The engine thrust is not what you need to know or even care about, you need to know what braking G you need to apply to reach zero velocity at the current distance from the selected base. You then apply that braking G using any engine you want.

Where can I find the reentry MFD ???

---------- Post added 05-27-10 at 12:15 AM ---------- Previous post was 05-26-10 at 11:30 PM ----------

Oh yes. I found reentry MFD and it does exactly what I want. First time I tried it I managed to land the LEM in manual just 2 Km from fra mauro with limited fuel from a starting fuel level of 95% after the base alignment burn. That is the first time I have EVER managed to land the LEM with limited fuel. Thanks guys, I knew what I wanted was going to be out there somewhere.