TransX What is "T to mnvre" used for in TransX?

[NOMAD]

After using TransX for some time ,I noticed "T to mnvre" in TransX's target view,I haven't find any answers about it after searching in the forum. What does it mean and used for?

 

[Mattyv]

After using TransX for some time ,I noticed "T to mnvre" in TransX's target view,I haven't find any answers about it after searching in the forum. What does it mean and used for?

I think it stands for "time to maneuver", but I use IMFD so I don't know.

 

[NOMAD]

I think it stands for "time to maneuver",

I also think so,but I don't know what does it used for?

 

[N_Molson]

Reading the documentation could probably help.

A manoeuver is an action lasting in time, like an engine burn of 200 seconds. In this case, you should begin your burn at T-100, and stop it at T+100. In the right direction, of course. Therefore "T" is the instant exactly between the beginning and the end of the burn.

 

[blixel]

I've been using TransX for about a year now and I've never really given much thought to that "T to Mnvre" line. The line right below it, "Begin Burn", obviously tells you when to perform the burn, so I've always been able to perform the burn at the right time.

Since this question was brought up in this thread, I took a look at one of my video recordings and I see exactly what N_Molson is saying.

I would re-explain it this way.

If you have to burn for 100 seconds, then you will start the burn (Begin Burn) when T to Mnvre is 50, and the burn should end when T to Mnvre is -50. So, one-half of the burn is done before reaching the precise maneuver point, and the other half of the burn is done after the precise maneuver point.

So the burn should be symmetrical.

Burns with the Align plane MFD work the same way. The information just isn't presented the exact same way.

 

[agentgonzo]

A bit if background. 'begin burn' never used to exist
It always used to assume that the delta-v happened instantaneously. This t to menvr was the time before this 'instantaneous burn'. Then I added 'begin burn' to take account of the time the burn took

 

[blixel]

A bit if background. 'begin burn' never used to exist
It always used to assume that the delta-v happened instantaneously. This t to menvr was the time before this 'instantaneous burn'. Then I added 'begin burn' to take account of the time the burn took

Are you the new developer for TransX? I kinda got the impression the developer abandoned it? But I guess he made it open source when he quit?

 

[insanity]

gonzo has been developing transx for a while, iirc. And he's done a damn fine job of it. You used to have to do calculations for burn times which was a PITA (I recall the old rule of thumb being that at t t mnrve you would have burned half of the needed dV, but I could be wrong). Either way, time to burn is a lot more helpful.

 

[agentgonzo]

Are you the new developer for TransX? I kinda got the impression the developer abandoned it? But I guess he made it open source when he quit?

Yes-and-no.
Duncan Sharp initially coded TransX waaaaaaay back (2006 maybe? Possibly even before that) but then stopped development on it. I picked up the source-code from him in 2007 and carried on development of it making improvements. It got open-sourced (with Duncan's permission) in 2008 or '9 and I ran out of time to spend on the project when I moved to Africa in 2010. I handed off support of the project then to Tofitouf (who seems to have not done anything with it, but at least that's explains why it's under his name in O-H). It's still open-source but I don't have the time to work on it anymore and no-one else seems to have wanted to pick up the baton.

---------- Post added at 10:40 ---------- Previous post was at 10:38 ----------

gonzo has been developing transx for a while, iirc. And he's done a damn fine job of it. You used to have to do calculations for burn times which was a PITA (I recall the old rule of thumb being that at t t mnrve you would have burned half of the needed dV, but I could be wrong). Either way, time to burn is a lot more helpful.

You could use an MFD called BurnTimeCalc to do the calculation for you, but yes, it was a pain to have to do it. I left the "t to mnvre" in in case anyone still wanted to use it, but Begin Burn seems much more helpful.