Did Tylo get nerfed?

[EdFred]

I never read release notes or dev notes, or anything release related. I was building a Tylo lander and noticed the cheat sheet on the wiki showed A LOT less dV needed to land, and that the gravity isn't the same as Kerbin's. Didn't it used to be the same acceleration as Kerbin? It now show's a bit less on the Wiki, and in KER.

[Pecan]

As I always understood it the round-trip, land and re-orbit, dV was about the same as a Kerbin launch. Harder to land in practice because there's no atmospheric drag but easier to launch from because of the lower gravity (and no drag).

[merendel]

No it hasnt changed other than added bioms. Its always been a bit less gravity than kerbin, its just that you have no atmo so the landing is harder but the takeoff easier. My rule of thumb for building tylo landers has been to just take off from kerbin to test it. If it can make it to orbit on its own with a bit of fuel left over it can probably handle tylo. Needs a bit more of a fuel reserve on games I'm runing FAR vs stock aero as it costs less to get to orbit on FAR.

[Kerano]

Tylo has always had 80% of Kerbin's gravity. There are different delta-v cheat sheets floating around with different values, some conservative and some optimistic.

In general though, Tylo takes about 2300 m/s to take off from (with a good TWR of 1.5-2+) and about 2700-3000 m/s to land on.

The landing delta-v is much more variable than the takeoff delta-v because it depends a lot on your technique and how much risk you're willing to take. It's possible to land using 2500-2700 m/s of delta-v, but it requires a very careful near-constant-altitude descent and coming to a safe landing speed just as you're about to make contact. Likewise it's quite feasible to use more than 3000 m/s of delta-v during the landing if your descent burn is non-optimal, or if you come to a safe speed well above the surface to reduce risk of impact, or if you have to spend extra time in flight finding a safe (flat) landing spot.

Edited February 5, 2015 by Kerano

[EdFred]

I remember the one cheat sheet I used saying something like 3300 dV to/from orbit, and now it is way less. I also thought it used to be 9.8m/s/s for some reason.

[Renegrade]

I remember the one cheat sheet I used saying something like 3300 dV to/from orbit, and now it is way less. I also thought it used to be 9.8m/s/s for some reason.

That cheat sheet one has been massively updated. It used to be rather generous with the safety margins in a number of places, while having fairly exact numbers elsewhere.

I actually have local backups of the older and newer one - the old one used to say 640 for a Mun landing, and 240 for a Minmus landing. The new ones says 580 and 180, which are more accurate. The older one varied from those figures by 1/10th and 1/3, respectively.

Here's my own calculations for Mun and Minmus (and Tylo), starting from the parking orbit specified on the old sheet, to a landing at 0 altitude:

Mun - 589.7

Minmus - 184.3

Tylo - 2,205.1

Obviously you want to pad these up with a safety margin, but I prefer using exact figures to start with so *I* can decide the safety margin size.

(Old sheet had Tylo as 3070, new one as 2270)

Edited February 5, 2015 by Renegrade
New sheet's tylo figure is 2270 not 2250.

[SkyRender]

The reason why Tylo tends to be given generous margins in those cheat sheets and the like is because every second you spend fighting gravity adds up quick there. Since gravity is so high, often landers have pretty low TWR relative to it, meaning inevitably you end up fighting gravity even more on the way down than you would otherwise.

[Whirligig Girl]

It's always been 0.8 gees.

[SorryDave]

Landing on all airless moons is easier in 0.90. Being able to SAS assist retrograde brings horizontal velocity to zero during landings, this allows the player to focus on vertical decent velocity.

[Renegrade]

The reason why Tylo tends to be given generous margins in those cheat sheets and the like is because every second you spend fighting gravity adds up quick there. Since gravity is so high, often landers have pretty low TWR relative to it, meaning inevitably you end up fighting gravity even more on the way down than you would otherwise.

Yeah, but it gave Minmus the same margin, percentagewise.

(and only 10% to the Mun)

I'm wondering if the data was basically through empirical testing only, and someone was good at Mun landings, and bad at other ones

[FleetAdmiralJ]

No, I don't think it's been nerfed. But my rule of thumb has always been 8000 dv Minimum - 4.5 - 5k to get down (I know it says 3k but c'mon, who are we kidding) and 3 - 3.5k to get back up into a decent orbit.

[Red Iron Crown]

Landing on all airless moons is easier in 0.90. Being able to SAS assist retrograde brings horizontal velocity to zero during landings, this allows the player to focus on vertical decent velocity.

Just be careful you don't zero out your vertical velocity before touchdown using this method, the ship will try to flip if you do.

Source: Hard personal experience.

[Liowen]

Just be careful you don't zero out your vertical velocity before touchdown using this method, the ship will try to flip if you do.

Source: Hard personal experience.

Also make sure you turn off the "follow Retro" thing as well......

Source: Hard personal experience as well.

[NecroBones]

Just be careful you don't zero out your vertical velocity before touchdown using this method, the ship will try to flip if you do.

Source: Hard personal experience.

Also make sure you turn off the "follow Retro" thing as well......

Source: Hard personal experience as well.

Yes, OMG yes. I've found that the retrograde -following capability has made landings much, much easier, but yes, if you're overzealous with your descent burns, you can quickly lose control. It's definitely not a true autopilot.

[magnemoe]

That cheat sheet one has been massively updated. It used to be rather generous with the safety margins in a number of places, while having fairly exact numbers elsewhere.

I actually have local backups of the older and newer one - the old one used to say 640 for a Mun landing, and 240 for a Minmus landing. The new ones says 580 and 180, which are more accurate. The older one varied from those figures by 1/10th and 1/3, respectively.

Here's my own calculations for Mun and Minmus (and Tylo), starting from the parking orbit specified on the old sheet, to a landing at 0 altitude:

Mun - 589.7

Minmus - 184.3

Tylo - 2,205.1

Obviously you want to pad these up with a safety margin, but I prefer using exact figures to start with so *I* can decide the safety margin size.

(Old sheet had Tylo as 3070, new one as 2270)

Makes sense, note that the two main problem with landing on Tylo is TWR, yes you can do the first part with low TWR but the last phase require high TWR. This is true for all bodies however the strong gravity on Tylo require an TWR of 2 or more to not use to much fuel. The final decent also uses a lot of fuel unless you are very brave.

[KerikBalm]

No, I don't think it's been nerfed. But my rule of thumb has always been 8000 dv Minimum - 4.5 - 5k to get down (I know it says 3k but c'mon, who are we kidding) and 3 - 3.5k to get back up into a decent orbit.

We're not kidding anyone, I budget 6 k, you really only need 2.5k to get back up (even less with a good TWR).

Done with a proper suicide burn, 3k is perfectly reasonable. It gives you about 500 m/s to lose on gravity drag, which at 7.85 m/s^2 means about 1 minute of holding a constant velocity while descending.

I even tried to budget less, and do it as a reusable SSTO (down and up again) using slightly modded parts (I increased the thrust of the aerospikes to be equal to the LV-T45, and made nosecones into fuel tanks with the same mass ratio as the 1.25m and 2.5m tanks)

Got down and back with 16 m/s to spare...

I think that time I budgeted something like 5km/s...

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xap1/v/t1.0-9/10644428_10103065172726113_3016715501731693213_n.jpg?oh=53720d8dc7d7a1750fd37b0ce9c1299b&oe=55503DC9&__gda__=1430979996_2c88bbc4d76b80653adc0fa7ac16b970

You don't need 8km/s.