Horizons Thrusters, Acceleration and High-G Planets

[TheMCP]

I did some tests/calculations about thrusters and high-g planets because i wanted to know whats the highest gravitation we can overcome with our thrusters, here's what i found out:

There seems to be no limit!
Our thrusters have unlimited power, the acceleration of our thrusters is always at least 5m/s² more than the gravitational acceleration, doesn't matter which class or rating.
Since even the iCutter Up-Thruster are capable of 5,2m/s² acceleration (Class E thruster, massratio 1,5), every ship should be able to land on every planet, regardless of gravitation.

The good news for explorers: you don't have to fit heavy thrusters, because the only difference better thruster make on high-g planets is their maximum speed, but they are not better at stopping (acceleration) your ship. They won't safe you from crashing into the planet after going in too steep/fast.


Example:
Up-Thrusters accelerate my Anaconda with 11,5m/s² in 0G, with 9,8m/s² in 0,18G, and 5m/s² in everything >0,68G, see data table below.
Second column are the expected values with the data from Cliffson and Taleden, the other columns are my observed values.


First Loudout, A7 Thrusters, 2160t Optimal Mass, 928,9t Current Mass:

Calculated with Speedmodifier 0G

9,77

G

6,73

G

1,41

G

0,68

G

0,18

G

0

G

Acceleration Forward

23,0

m/s²

23,2

m/s²

23,1

m/s²

m/s²

m/s²

m/s²

23,2

m/s²

Acceleration Backward

11,5

m/s²

11,7

m/s²

m/s²

m/s²

m/s²

m/s²

11,5

m/s²

Acceleration Sideward

11,5

m/s²

11,7

m/s²

m/s²

m/s²

m/s²

m/s²

11,6

m/s²

Acceleration Up/Down

11,5

m/s²

5,0

m/s²

5,0

m/s²

5,0

m/s²

5,0

m/s²

9,8

m/s²

11,5

m/s²

Acceleration Up w. Forward Thrusters

5,0

m/s²

5,0

m/s²

9,4

m/s²

16,5

m/s²

21,2

m/s²

23,2

m/s²

Gravitation Acceleration

95,8

m/s²

66,0

m/s²

13,8

m/s²

6,7

m/s²

1,8

m/s²

0

m/s²

Acceleration Up/Down + GAcce.=

Grav > Thruster

Grav > Thruster

Grav > Thruster

11,6

m/s²

11,5

m/s²

11,5

m/s²

Gravitation Acceleration

95,8

m/s²

66,0

m/s²

13,8

m/s²

6,7

m/s²

1,8

m/s²

0

m/s²

Acce. Up. Forward Thrusters + GAcce.=

Grav > Thruster

Grav > Thruster

23,2

m/s²

23,1

m/s²

23,0

m/s²

23,2

m/s²

Second Loudout, E5 Thrusters, 840t Max Mass, 839,9t Current Mass:

	Calculated with Speedmodifier 0G	6,73	G
Acceleration Forward	17,0	m/s²	17,0	m/s²
Acceleration Backward	8,5	m/s²		m/s²
Acceleration Sideward	8,5	m/s²		m/s²
Acceleration Up/Down	8,5	m/s²	5,0	m/s²
Acceleration Up w. Forward Thrusters			5,0	m/s²

Thanks Cliffson’s (https://forums.frontier.co.uk/showthread.php?t=182465) and Taleden’s (https://forums.frontier.co.uk/showthread.php?t=182057) for their research about thrusters and acceleration.
Tests were done with 4pips to engine, I recorded my tests and measured the time in a mediaplayer.

Additional Note:

• acceleration seems to be affected by the speed modifier curve (see Taleden’s thread).
• acceleration in 0G has a peak performance (low acceleration in the beginning, max acceleration in the blue zone, low acceleration near top speed), while the acceleration in 9,77G seems to works different in some cases, it’s linear from 0% to 90-95% speed and then drops off drastically (any direction), i don’t know why this is the case, have to test it further.
• I still have to do some research about boost acceleration

English is not my native language, feel free to correct (especially technical terms).



Regards, Cmdr Eirene

 

[Cynaqq]

Thanks for the time you put into this CMDR! Very useful information.

Your English is fine, don't worry about it. It's not my first language either, do you see me mention it

+1

 

[Lupin]

Thanks for the information, now we are in open not beta more information the better.

 

[TheMCP]

Forgot to post my loadout, but i can't edit my post (do i need 3 posts to be able to edit?)
http://coriolis.io/outfit/anaconda/...4v42i2f.Iw18WAMOzJA=.EwBj4yutlEg=?bn=Anaconda

Cmdr Eirene

 

[shadmar]

It seems to be some kind of cheating?, I've been doing alot of testing on HD148937-3 myself in D-rated modules and I would excpect forward thrusters to accelarate alot faster than vertical thrusters, but they don't as you have observed.
Anyways +1 for the science effort here.

 

[TheMCP]

I think i found the answer, the thruster acceleration is reduced by gravitation, but the minimum is 5m/s².
In this case it's possible to land on every planet, no matter how high the gravity it.

I'm gonna do some additional test to get a curve for acceleration in 0G and do a graphical representation of the mechanic.
It's not realistic, but we know the flight model can't be realistic because of gameplay reasons.


CMDR Eirene

 

[shadmar]

I think you are correct, I still get 5m/s accel when at the very entry of orbital flight around HD148937-3 at 6Mm height. Around 7g
If I'm just above orbital flight and drop out, I fall like a stone. So orbital flight must trigger some "special" thrusters aswell.

When looking at my build ASP using 5D thrusters it says: Optimal Mass: 630T Maximum Mass: 945T ( http://coriolis.io/outfit/asp/02A5D...i022f2i.Iw19gDM0kA==.AwiMIytdKA==?bn=Shadmar2 )
My ship weight is 350T, so I would think maximum gravity for these thrusters would be 945/350 ~ 2.7g, at this gravity level I would have 0m/s acceleration.

 

[TheMCP]

So orbital flight must trigger some "special" thrusters aswell.

My ship weight is 350T, so I would think maximum gravity for these thrusters would be 945/350 ~ 2.7g, at this gravity level I would have 0m/s acceleration.

Hi Shadmar

Our thrusters have unlimited power, the acceleration of our thrusters is always at least 5m/s² more than the gravitational acceleration.
The problem with dropping like a stone is, when you are already dropping towards the planet, let's say with 500m/s, you need 100 second to stop you ship from falling (500m/s : 5m/s² = 100s), it's possible but most of the time you will be dead before you can stop your ship from falling.

About your Asp and gravitation, you can't calculate it like that, you need to know the acceleration and your current mass.
For my Anaconda a 1,17G (Up-Thrusters) or 2,35G (Forward-Thrusters) Planet would be the maximum if it wasn't for the hidden 5m/s²m limit.

 

[Billexista]

If only you at least generated more heat with high G planets, but oh well, gameplay reasons, no worry just drop it there and be worry free. So elite dangerous or noob handholder? I can't decide and sometimes it feels that game can't decide on that either. Settlement on 5G planet is just ultra LOL to me. Newborn baby would be from 10-25KG on high G planet around 5G so yeah not happening.

And if some wisecrack is going to say but duuuh anti gravity and artificial gravity stuff, then why the hell are stations rotating and doing centrifugal gravity rotation if they have the tech for just standing there and having gravity?

Also damn nice analysis of gravity and thrusters in elite.

 

[TuxedoSteve]

For anyone that needs a lore explanation:
The explanation for this behavior, I remember reading somewhere, is that the vertical thrusters are 'overloaded' beyond normal power, this enables them to generate much more thrust, but at the cost of all other thrusters having reduced acceleration due to it diverting power from those thrusters to the verticals.

This is also very evident in some situations, for example, a Fer De-Lance on a planet with 1.3g of gravity. Normally the FDL's reverse thrusters generate somewhere in the realm of (probably) 15m/s^2 but in a 1.3g planet they can't even hold the ship in the air.

 

[puca]

Very interesting, thank you for this. I observed empirically that very weak thrusters let you hover on high G worlds -- this confirms this. Somewhat disappointing actually. They should have added a "this thruster is rating for this max G" to the UI instead.

 

[TheMCP]

For anyone that needs a lore explanation:
The explanation for this behavior, I remember reading somewhere, is that the vertical thrusters are 'overloaded' beyond normal power, this enables them to generate much more thrust, but at the cost of all other thrusters having reduced acceleration due to it diverting power from those thrusters to the verticals.

Not in this case, the forward/backward/sideward acceleration is the same on a 9,77G planet as in 0G.

This is also very evident in some situations, for example, a Fer De-Lance on a planet with 1.3g of gravity. Normally the FDL's reverse thrusters generate somewhere in the realm of (probably) 15m/s^2 but in a 1.3g planet they can't even hold the ship in the air.

I tried it, you are right! The reverse thrusters can't even hold the Anaconda in place on a 0,32g planet, which is just wierd, even 1g shouldn't be a problem.... "gameplay reasons" i guess....

 

[Kalpa]

Necroing this thread, as I've just finished some rather quick and dirty experiments myself. Results are in line what has been presented here already. Has anyone done further and more systemic research on the matter? (Here my poorly presented results, link is to a specific post. Read further down the thread for more)

 

[Zueuk]

It's not realistic, but we know the flight model can't be realistic because of gameplay reasons.

And I wonder what reasons are these...

We can get right next to a black hole, we can land on any planet regardless of gravity - and nobody even cares about humans not feeling very well on high g... Why is this game still called Elite *Dangerous*?

 

[Shar]

Great work, it goes a long way toward the is it a game or a sim question, the devs will be scratching there heads wondering if they are going to need a physicist on staff.

But seriously, nice work. be interesting to see where we stand by EDH 2.5.

 

[VR andysonofbob]

I personally found this unbelievably helpful!

So the cut and thrust of it is the minimum up thrust is 5m/s/s?

Thanks!

 

[SvennoJ]

And I wonder what reasons are these...

We can get right next to a black hole, we can land on any planet regardless of gravity - and nobody even cares about humans not feeling very well on high g... Why is this game still called Elite *Dangerous*?

It's dangerous because a momentary lapse of concentration can kill you!

The magic boost or minimum 5 m/s2 thrust only works for the bottom and rear thrusters, while flying horizontal or vertical.
Deviate too much from these 2 orientations and you will go down fast. At 9g it only takes 5 seconds to reach the 500 m/s cut off point.
That's another unfortunate gameplay restriction, yet for now there is still a way to break the speed barrier.
I reached 9230 m/s on a landing from 845km up. https://forums.frontier.co.uk/showthread.php?t=225057&page=6&p=3452244&viewfull=1#post3452244
Then got 18% hull damage on touch down when the back landing gear touched the ground first and landed the ship with the front a mere 6 meters up. It's plenty dangerous landing and taking off at 9.7g

It's a step back from Frontier Elite for MMO and combat reasons. There is ksp for orbital flight mechanics. ED is a galaxy simulator.

 

[CTCParadox]

Would have been nice to have more difference between ships on this. The keelback and panther clipper seem to be great candidates for high g landers with their rotating engines.

 

[SvennoJ]

Not in this case, the forward/backward/sideward acceleration is the same on a 9,77G planet as in 0G.

I tried it, you are right! The reverse thrusters can't even hold the Anaconda in place on a 0,32g planet, which is just wierd, even 1g shouldn't be a problem.... "gameplay reasons" i guess....

Intrigued by not being able to hover sideways above 0.3g I checked what's going on:

Horizontal axis: local gravity
Vertical axis: net vertical acceleration (ship rotated in position to provide thrust directly against gravity)

Main and aft thrusters work as expected, however side and bow thrusters act strangely against gravity. From 0.10g to 0.30g their thrust is reduced from 10.2 m/s2 to 2.0m/s2. 0.285g is the highest in which you can make a barrel roll without falling. The bow thrusters show even stranger behavior. Between 0.10g and 0.28g the ship won't fall on it's nose, but it will wobble as if dangling on a string.
From 0.30g to 1.00g the ship reaches a terminal velocity and will stop accelerating further at:
0.30g nose down unstable, holds at 63 m/s
0.40g nose down unstable, holds at 72 m/s
0.50g nose down unstable, holds at 80 m/s
0.75g nose down unstable, holds at 98 m/s
1.00g nose down unstable, holds at 117 m/s
At 1.25g and beyond nose down position has the full 10.2 m/s2 (1.04g) reduction in acceleration again. So at 1.25g, nose down, you accelerate towards the ground at 0.21g

I have no idea hat causes this. The placement of the thrusters giving FA trouble?

Ship used http://coriolis.io/outfit/anaconda/...50s0sf3v4432f2i.AwRj4yq5VMg=.EwBjIRg8d3rMUwFA

 

[SvennoJ]

Up to 1.55g aft down, ie landing like a rocket is the fastest way to slow down. Above that horizontal or vertical are the same and your stopping distance is (speed^2) / 10.
At 100 m/s 1.0km to stop, 200 m/s 4.0km to stop, 500 m/s 25.0km to stop. I guess that's why they capped the downwards speed at 500 m/s, 25km and a 100 second wait is quite long already.

You can check the graph for what counter thrust the thrusters can produce where you are landing and use this: d = (g * ((v/g)^2)) / 19.6
For example at 0.3g: bottom thrusters provide 0.74g, takes 6.2 km to stop at 300 m/s, while aft thrusters provide 1.76g, takes 2.6 km to stop

Or easier to use the classic version: d = 1/2 * a * ((v/a)^2)
Your max deceleration is max engine thrust minus g*9.8, At 0.3g bottom thrusters a = 10.2 - (0.3*9.8) = 7.26 m/s2, aft thrusters a = 20.2 - (0.3*9.8) = 17.26 m/s2

There are links in the op for max acceleration for different ships as this is all based on the Anaconda I'm flying.
A simple indication showing your current vertical stopping distance, like the time counter in super cruise, would be very helpful for landing.