Project JBT B1200 Aircraft Tug

[Interceptor]

Thanks for the info,Keep up the great work.

 

[DaveS]

I won't because the mesh for the current one is not very good. If I get a better mesh I can easily make it if I can get the appropriate values. The source code is included for those who wish to make their own Tug like vessel too.

How about this one:

It's an old Rolls-Royce model dating back to the 1960's as I have seen photos of it towing Saturn 1B stages. Weight is 29250 kg and it measures 5.66m long, 2.95m wide and 2.28m high. There's a similar unit at EDW that is white in color unlike the KSC one which is yellow. Max towing speed is 8 km/h.

 

[Loru]

JBT 1200 - or as close I could get to it

 

[tl8]

First real release. Thanks to Loru and Woo482 for the Tug mesh and the Towbar mesh.

Still plenty of bugs. No guarantees about anything.

The animations don't work again. That is more a compatibility problem more than anything.

Read the short manual for the new key commands. If there is no *vesselname*_Towbar vessel, it will be created.

I will slowly add features and fix bugs, as you can tell development is in fits and starts. Next main step is to complete the towing animation. Then I plan to get lights and start fixing bugs.

http://dl.dropbox.com/u/3550991/jbt_1200_Alpha0.01.zip

 

[tl8]

Progress is occurring!

I plan to release a full update by the end of the weekend

ATM I have fixed the HUD bug, added a flashing warning light and added a headlight.

I hope to finish off the lights this weekend and allow it to become cargo. If I get time I will sort the sounds.

@DaveS I have started fixing the pitching bug. I am trying to find the root cause but progress is slow. I have a fix that my mitigate the problem, but nothing that will remove it.

 

[tl8]

As Promised a new Alpha. This has working sound, working lights and the exhaust sometimes works. It is now a valid XR5 payload (Centre slots). New bug in that the movement is now somewhat unstable and reverse doesn't work.

Next release I hope to fix the dynamics bugs. These are the above bug, the pitch up bug and hopefully the steering animation bug. I also hope to finish the towing animations. I would expect it to be a few weeks but will be shorter if I have help finding the cause of the bugs.

http://dl.dropbox.com/u/3550991/JBT_B1200_Pushback_Tug_Alpha0.02.zip

 

[tl8]

First up, the drive and the pitch bug bugs are now gone. The wobbly wheels still remain, but the code for that is now a lot easier to create a fix.

On the towing animation, I have come up with a new model (again). This hopefully will be the final implementation of the forward towing animations.

It is basically going to be a circle model. Each element will turn on an arc from a circle. The size of circle will depend on the rudder position.

Each element will track through the list of circles as the tug enters them. Each element can only move onto the next circle once it has finished the circle it is in. To track progress through the circle, the distance from the start point is tracked. Using the Chord angle formula, the element heading can be calculated. When the element heading is the same as the exit heading (Which is recorded), the element has finished the arc and can move to the next one (If present).

Hopefully some of that makes sense. When I get it working, it should look ok and be somewhat close to the real world.

Once that is done, I then have the 'joy' of trying to work out how to get the reverse case working.

 

[tl8]

Started work on it again.

This week I want to get UMMU working.

Currently have the basics in place. Now I just need to add action areas and crew editing. I have some ideas on how to use the complex flight model, so that should appeal to the more expert users.

 

[tl8]

UMMU stuff is now mostly done. There is a bug with the add crew member which I might sort out.

See the manual for the complete list of controls, a few things have changed.

http://dl.dropbox.com/u/3550991/JBT_B1200_Pushback_Tug_Alpha0.03.zip

I expect to release at least one more alpha. This will most likely be the exhaust system (Which "should" be working") and better sounds.

After these "small" changes, the real work of doing to towing physics will begin.

I am hoping this (4th/5th) attempt will work, because everything looks rubbish without it.

 

[Woo482]

Looks like you just forgot to call the "AddUMmuToVessel();" function in clbkPreStep, I've just added the highlighted lines and it's working fine.

void JBTB1200::clbkPreStep (double simt, double simdt, double mjd){

	//UMMU Controls
	if(Crew.GetCrewTotalNumber() < 1 && complex > 0) {
		//Disable the ship
		SetADCtrlMode(0);
		SetAttitudeMode(RCS_NONE);
		SetThrusterResource(th_Input,NULL);
	}
	else {
		//Enable the ship
		SetADCtrlMode(7);
		SetAttitudeMode(RCS_ROT );
		SetThrusterResource(th_Input,fuel);
	}
	
[COLOR="Red"]	// "AddUMmuToVessel" function
	AddUMmuToVessel();[/COLOR]
	
...
}//Prestep

 

[DaveS]

Just gave the latest alpha a test run and it is much improved over the last version. Very solid, no issues during an unloaded move from the KSC LC-39 barge terminal to the VAB, except for the previously noted forward wheel spin issue.

By the time I had reached the VAB, the wheels were perpendicular to the rest of the vehicle. No issues at all maintaining a 8 km/h tow speed.

 

[tl8]

except for the previously noted forward wheel spin issue.

By the time I had reached the VAB, the wheels were perpendicular to the rest of the vehicle. No issues at all maintaining a 8 km/h tow speed.

Yes, this is still the issue bugging me.

It has something to do with the steering and rotation of the drive wheels.

It is a parent child animation but a lack of examples like this are annoying.

 

[DaveS]

Yes, this is still the issue bugging me.

It has something to do with the steering and rotation of the drive wheels.

It is a parent child animation but a lack of examples like this are annoying.

If you want, you could check out the SSU sources as I believe we're using parent/child animations for the payload bay doors/centerline latches and the Ku band antenna deployment.

 

[tl8]

http://dl.dropbox.com/u/3550991/JBT_B1200_Pushback_TugAlpha0.04.zip

The last Alpha (Hopefully). Updates the sounds (Thanks DaveS) and removes the particle stream code.

The Beta will be up on OH and will include the new towing physics.

This new idea for the physics will be my last, if it doesn't work then project is dead.

It will basically make the towed vehicle follow the path of the tug. While not accurate, it would however look ok and hopefully that will be enough.

The wobbly wheels problem still exists. Many people have told me where the problem is, but are yet to actually find a solution.

 

[DaveS]

A few pre-beta notes:

• The sound files are in the wrong folder. They should be in Sound\JBT_B1200, not Sounds\JBT_B1200
• Remove dependancy on the XR-5
• Remove dependancy on Ascenion Island

Here's a scenario that has the JBT-B1200 in place ready to tow Atlantis to the VAB(no add-ons required). This scenario mimics the pre-Challenger era when the orbiters actually were rolled over from the OPF to the VAB on their own landing gear and flight tires.

BEGIN_DESC
Contains the latest simulation state.
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 55987.5564377642
END_ENVIRONMENT

BEGIN_FOCUS
  Ship B1200
END_FOCUS

BEGIN_CAMERA
  TARGET B1200
  MODE Extern
  POS 6.75 131.02 -14.18
  TRACKMODE TargetRelative
  FOV 40.00
END_CAMERA

BEGIN_HUD
  TYPE Surface
END_HUD

BEGIN_MFD Left
  TYPE Map
  REF Earth
  BTARGET Cape Canaveral
  POS 0.00 0.00
END_MFD

BEGIN_SHIPS
B1200:JBT_B1200
  STATUS Landed Earth
  POS -80.6543500 28.5868200
  HEADING 79.28
  AFCMODE 7
  PRPLEVEL 0:1.000000
  NAVFREQ 0 0
  UMMUCREW Eng-Garu_Falcon-28-65-74
END
STS-101:Atlantis
  STATUS Landed Earth
  POS -80.6546100 28.5867770
  HEADING 79.28
  AFCMODE 7
  NAVFREQ 0 0
  CONFIGURATION 3
  GEAR 1 1.0000
  ARM_STATUS 0.5000 0.0000 0.0000 0.5000 0.5000 0.5000
  SAT_OFS_X 0.00
  SAT_OFS_Y 0.00
  SAT_OFS_Z 0.00
  CARGO_STATIC_MESH Carina_cradle
  CARGO_STATIC_OFS 0.00 -1.65 0.05
END
END_SHIPS

 

[markweasal]

any new things with it

maby you can add ground crew ummus to it and paint them like on aircraft carriers red=fuel purpule "grapes"= high explosives i dont know what therest do however

 

[tl8]

Ummu is added.

New Alpha with the Sound folder renamed.
http://dl.dropbox.com/u/3550991/JBT_B1200_Pushback_TugAlpha0.05.zip

When I do the beta, I will add a few scenarios. Some that use the DG, XRs, DGIV, TX and the shuttle. I will also put them in a variety of locations

 

[PrestonJames]

Not sure what I'm doing wrong, but with this latest update, the tug won't release an attached vessel. Have you experienced this problem?

 

[DaveS]

Could you lower speeds at which the different engine sounds kick in? Currently they're set a bit high as the general maximum tow speed is no more than 8 km/h(5 mph). So you're never going to be blazing around at 25 km/h(top speed shown on the HUD).

 

[tl8]

Not sure what I'm doing wrong, but with this latest update, the tug won't release an attached vessel. Have you experienced this problem?

Ok, yes, there seems to be a bug when it is in Complex mode. Looks to be an issue with action areas.

---------- Post added at 08:38 AM ---------- Previous post was at 08:32 AM ----------

Could you lower speeds at which the different engine sounds kick in? Currently they're set a bit high as the general maximum tow speed is no more than 8 km/h(5 mph). So you're never going to be blazing around at 25 km/h(top speed shown on the HUD).

That is more a problem with the engine simulation.

Currently the engine revs are related to the force that the tug is pulling with. Now a partial problem to that is that the mass of the vessel being towed is not accounted for.

That said, I can reduce it a bit more but the problem will still exist.