I am new to the Orbiter, and Tug eXperimental is my first craft that i fell in love with :hail: TX
I am just launched XR2 with payload to the LEO (extremly low) and returned back home to the SRC - Space Port. Full payload mass was 53.2 Kkg. There was about 40 Kkg fuel left for reenter and return.
Well, the orbit was only 125 km, but i am believe, that fully supplied XR2 can handle this.
I used XR2 as payload, for its damage system, and adjustable mass. After a few failures (once, even failure of the heating shield occurred), finally XR2 was delivered on LEO intact and fully operational. That was sweet hours
of piloting.
Actually, i am believe, TX can be served as first stage for payloads with mass from 70 Kkg Well, there is problems that should be solved - prolonged runaway and auto gear retracting at 200 ms.
Also there is a question, will be rotational moment enough for lift off (with gears retracted at 200 ms, answer is no, if runaway is not specially modified, - have a positive angle attitude, for example). TX use RCS to solve this problem already (jet it not animated, and RCS fuel did not decreasing). You can see this if you use "Fly by wire" addon and assign elevator and RCS Y axis on different manipulators. It just cant lift off with payload more than 20Kkg with aero controls only. It is wild guess, but it is not possible to lift off with DG and possible without payload.
That invisible RCS help ends, when gears fully retracted. (almost immediately after takeoff in normal conditions).
VC for TX have bug (maybe just for me), it uses RCS with AF all the time, that depletes RCS fuel very fast. Can be solved if RCS controls assigned to other manipulator or just switched off (than use keyboard for RCS) with "Fly by wire".
RCS fuel can be saved by using trim controls whenever its possible (below 75km), after first bump (at about 50-40 AOE initially to 30 in lowest point point, you can descent only with trim control (with AOE about 13 Deg), DOC file for TX describes this.
After retro burn from 200 km LEO, TX will go approximately 1,5 circles around earth. 0,5 circles to second enter in the atmosphere after first bump, and full circle around earth in high atmosphere. (its much longer than ascent and requires lot of attention, be ready) So, plan retro burn on opposing to base side of the earth with periapsis near the base.
Use of Aerobreaking MFD seems to be limited due to RCS fuel saving tactic, but it comes very handy at later stages of descending, for base approach without main engine use.
And TX is beautiful, just astonishing beautiful plane, ans as already said, - i am just love it.
:blush: