TVM: Difference between revisions

Revision as of 03:09, 27 October 2026

TVM (Target Velocity Match)

TVM evaluates the velocity of a selected target and uses the ship thrust to match both it's speed and direction.

Orbital rendezvous: Clients with the new full-page Orbit instrument can plan a transfer to a future point approximately 5 km behind a station or spacecraft and execute it with DOR. See the Orbit rendezvous procedure for planning, warnings and execution. TVM is a separate target-relative velocity control; selecting a TVM closure speed does not calculate an orbital transfer. The manual TVM approach procedure below remains separate from the Orbit planner.

DOR rendezvous handoff: When DOR successfully completes a rendezvous, it automatically engages TVM with TVM SET 0.000 km/s and keeps the selected station or spacecraft. The Autoflyte disconnect sound plays once as DOR switches off. Manual cancellation and automatic aborts do not trigger this handoff. You can also select TVM manually while DOR is active; this disengages DOR and resets the TVM closing speed to zero. See rendezvous completion and TVM.

Surface journeys (planning-only revision, pending client rebuild): The Orbit surface planner compares AUTO / ATM / SUB / ORB profiles at a chosen PASS deadline. PLAN ONLY / ATM HANDOFF does not automatically select TVM or another Autoflyte mode and does not command atmospheric flight or landing. The pilot remains responsible for selecting and operating suitable controls.

Closure Rate

At a desired closing speed of 0.000 km/s, TVM commands a velocity match with the selected target. It does not actively hold a particular separation, restore the Orbit planner's 5 km trail position, or provide collision avoidance. Monitor actual separation and relative motion during the approach; engine response and external forces still affect the result.

If you adjust the desired to a positive number you will be moved parallel to the target plus the closure speed and direction you are aiming. Your direction the nose is point and the desired closure speed is added to the target's vector as an additional vector.

If you adjust the desired to a negative number you will be moved parallel to the target minus the closure speed and direction you are aiming. Your direction the nose is point and the desired closure speed is subtracted from the target's vector.

Vertical Landings

With a ground waypoint selected as the reference, TVM allows a controlled descent in a VTOL vehicle with suitable vertical thrust. A vehicle or ARJ stationary on the ground can also provide a ground-relative velocity reference.

Select TVM with K and use 0.000 km/s commanded closing speed to damp motion relative to the selected reference. On the E-10, E-11, A-4 and W-6, ground-referenced TVM in BCL provides these vertical controls:

Hold F9 to request maximum upward thrust. Engine condition, loading, attitude and the VTOL operating limits still constrain the delivered lift.
Hold F8 to select a descent rate based on radio height above ground. The nominal schedule allows faster descent above 100 m AGL, reduces toward 10 m/s by 100 m, and slows toward 1 m/s near the landing surface. The controller begins slowing sooner when available braking thrust and engine response require it; rates can therefore be lower than these nominal values.
Release either key to request hover again. Hover means zero vertical velocity relative to the ground reference, not a selected altitude or position hold. Allow for the aircraft's response and remaining momentum.

The descent selection preserves margin below the VTOL airflow limits. The Manx also observes its door-pressure limit, which depends on local air density. A heavy or damaged aircraft may not have enough lift to arrest a descent or hover.

In this BCL ground-reference mode the closing-speed setting controls the horizontal component along the nose direction; F8/F9 control the vertical request separately. Other references, ACL operation and the P-13/T-19 retain their usual TVM and translation behavior. Main-engine VTOL remains atmospheric; RCS supplies vertical translation outside its operating envelope.

Below-stall leveling: while matching a ground waypoint or grounded vehicle in subsonic flight, TVM uses thrust augmentation to bring the nose and wings level with the local horizon. Keep thrust augmentation enabled and serviceable, with cockpit power available. Leveling controls pitch and roll; you retain yaw control. Moving the pitch or roll control overrides leveling on that axis, and centering it resumes the assistance.

Leveling is strongest below 90% of the computed stall speed and fades to zero at the stall speed. It also fades from Mach 0.8 to Mach 1, using the full airflow speed, so low IAS during fast ascent or re-entry does not command a landing attitude. It does not apply to airborne or orbital targets, while docked or on the ground, during flight freeze, or without valid stall-speed data and available rotational thrust. It becomes available again automatically when those conditions permit, while TVM remains selected. Available thrust, vehicle mass, damage and wear limit how quickly the aircraft can level.

Monitor attitude, vertical speed, height above ground and the landing area throughout the descent. Selecting a ground waypoint supplies the velocity reference; it does not steer the vehicle to that waypoint's position or provide terrain avoidance or an automatic flare. TVM disengages on touchdown. See Autoflyte special modes for the relationship between TVM and ordinary flight guidance.

Using TVM to approach a Space Station

One of the most useful things you can do with TVM is docking with CPOC or TAC

Remember as the station orbits the planet of course it is a giant circle. E is a perfect circle for the stations, CPOC is at 3000km often the shortest route is through the planet. You MUST always monitor your orbital path.

Look at the Ground Track figure out where the station will be when you have climbed out of the atmosphere.
Take off heading on a course to intercept.
Climb to approximately 100KM
AIM the nose of the ship at the Direction of target of the station
Turn On TVM and set it to a close speed to 3-4KM/sec closure speed Version 2.2.7.3 and newer the game controller set for "Engine 1" will control TVM closure)
Keep aiming the nose at the station
Keep looking at VSI to make sure it is NOT going negative
As you get close to the station start to slow down. An E-10 NOT full of cargo will take over 250KM to to slow to 0.250 KM/sec A heavy E-10 can take over 400Km. Brake early your goal is to not have the station remind you of the 0.250 km/sec speed limit.
Ask for clearance to dock.
Stop with in 100m of the new waypoint.
Press 'd' to dock

Congratulations you are docked.

@@ Line 18: / Line 18: @@
 With a ground [[Waypoint|waypoint]] selected as the reference, TVM allows a controlled descent in a [[VTOL]] vehicle with suitable vertical thrust. A vehicle or [[ARJ]] stationary on the ground can also provide a ground-relative velocity reference.
-Select TVM with '''K''' and use '''0.000 km/s''' commanded closing speed to damp motion relative to the selected reference. Gravity can still produce a gradual descent while the vertical thrusters oppose the sink. The actual descent rate depends on the vehicle's mass and available thrust; TVM does not command a selected descent rate or hold a fixed height. The closing-speed setting acts along the direction the nose is pointing, so it is not a vertical-speed selector.
+Select TVM with '''K''' and use '''0.000 km/s''' commanded closing speed to damp motion relative to the selected reference. On the [[E-10]], [[E-11 Saint|E-11]], [[A-4]] and [[W-6]], ground-referenced TVM in '''BCL''' provides these vertical controls:
+* Hold '''F9''' to request maximum upward thrust. Engine condition, loading, attitude and the [[VTOL#Atmospheric operating envelope|VTOL operating limits]] still constrain the delivered lift.
+* Hold '''F8''' to select a descent rate based on radio height above ground. The nominal schedule allows faster descent above 100 m AGL, reduces toward 10 m/s by 100 m, and slows toward 1 m/s near the landing surface. The controller begins slowing sooner when available braking thrust and engine response require it; rates can therefore be lower than these nominal values.
+* Release either key to request hover again. Hover means zero vertical velocity relative to the ground reference, not a selected altitude or position hold. Allow for the aircraft's response and remaining momentum.
+The descent selection preserves margin below the VTOL airflow limits. The Manx also observes its door-pressure limit, which depends on local air density. A heavy or damaged aircraft may not have enough lift to arrest a descent or hover.
+In this BCL ground-reference mode the closing-speed setting controls the horizontal component along the nose direction; F8/F9 control the vertical request separately. Other references, ACL operation and the P-13/T-19 retain their usual TVM and translation behavior. Main-engine VTOL remains atmospheric; RCS supplies vertical translation outside its operating envelope.
 '''Below-stall leveling:''' while matching a ground waypoint or grounded vehicle in subsonic flight, TVM uses thrust augmentation to bring the nose and wings level with the local horizon. Keep thrust augmentation enabled and serviceable, with cockpit power available. Leveling controls pitch and roll; you retain yaw control. Moving the pitch or roll control overrides leveling on that axis, and centering it resumes the assistance.