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Question

Im attempting to build a tylo lander, and im wonder a few things about it.

1. What kind of TWR should i have for my decent stage

2. How much Delta v would it take to land, and return to LTO (Low Tylo Orbit)

3. I am using a Ion Tug to de-orbit my lander, so I don't need to worry about that. 

 

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15 minutes ago, Starslinger999 said:

Im attempting to build a tylo lander, and im wonder a few things about it.

1. What kind of TWR should i have for my decent stage

2. How much Delta v would it take to land, and return to LTO (Low Tylo Orbit)

3. I am using a Ion Tug to de-orbit my lander, so I don't need to worry about that. 

 

Here are the answers to your question:

Question 1:

Your decent should have TWR of 2.5 cuz it will make it easier to land.

Question 2:

(for 60 Km and when ascending 30km above the surface to orbit) About 5,750 m/s to land at the surface and return

Happy landings, bro :D

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For your TWR, anything above 1 can work, but starting with 2.5 is a minimum for something comfortable.

As for Delta-V, the theoretical minimum is 4540 m/s (for landing then going to LTO), but I wouldn't pack less than 5000 m/s if I were you.

I'll just add that, the higher your TWR is, the less delta-V you need, for two reasons :

1) During descent, you'll kill your horizontal speed faster, reducing the time during you gain vertical speed due to gravity

2) During ascent, you'll reach your orbital speed faster, reducing gravity losses.

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Eve is the dominatrix of return trips.  You don't have to love it but you do have obey.
Tylo is a poodle!  (<-- This is not what I wrote!  Apparently a female dog is censored to be a 'poodle'?!  FFS, what are special snowflakes coming to).  You are simply not a consideration.

Landing and (re)launch are each at least 2.2km/s so you need a minimum 5km/s in a lander to be at all comfortable.

Edited by Pecan

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More than you think.   Imagine lifting off from Kerbin without an atmosphere, and you'll be just about right.   Leave everything you can on the surface (landing gear, descent stage, etc) and use a 'tug' in orbit for the interplanetary transfers.

 

Here's what I built as a one-way lander probe (no attempt to lift back off).  1.7 TWR for the lander, nuclear interplanetary transfer and insert stage.

 

tylo.jpg

Edited by sdrevik

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According to my notes, my one and only Tylo mission took about 3400 m/s to land, and about 2650 m/s to launch.  My designed required a staging event part way through the descent.  About the first 2/3 of the dV was with a TWR of about 1, and the final 1/3 of the dV was with a TWR of about 2.5.  If I did it over again, I would probably use a higher TWR throughout.

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Here is a Tylo Lander that I haven't tested yet (still en route to Jool in career mode. It's another year out).  What do y'all think? It has about 6500dv total and 1.7 TWR at the first stage, and as you can see the side tanks are asparagus staged. By the numbers it should do the job but I'm still nervous about it. I just wish there was a longer mk0 rocket fuel tank so I wouldn't have to use so many Oscars and save some part count.  

glwJa9p.png

Edited by Lunar Sea

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I have a design with roughly 5300 dv and its lightweight. Its great for my Jool 5 Mission Disign

The landing stage has 2 side mounted Aerospikes with radial tanks. It has a decent TWR on Tylo. 

GAlQirq.jpg

Another question: is the top stage with 1400m/s dv capable (When fully fueled, and detached from Tylo Module) of landing on Vall and returning to low Vall orbit? 

 

Edited by Starslinger999

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1 hour ago, Starslinger999 said:

 

Another question: is the top stage with 1400m/s dv capable (When fully fueled, and detached from Tylo Module) of landing on Vall and returning to low Vall orbit? 

 

I don't think so, Vall takes about 1900 or so for the orbital round-trip. I was working on a very similar design with side-mounted Oscar tanks and wound up having to add some more tanks (toroidal) to make it have enough. 

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Im back with the Mk 2!

(Now with 100% more science!)

o7Zmrey.jpg?1

This is my Low Grav lander/Tylo Upper stage now with 1934 m/s Dv

NpjjL88.jpg

And this is the lander with the Tylo attachment. With 5159 M/s Dv

Note: This is not meant for Laythe, I have a separate attachment for it. (Ie a Wiplash with a bit of Liquid Fuel on it)

 

Edited by Starslinger999

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Tylo is hard to land and return on so, if you aren't already, I'd suggest "trying it in the simulator" first by HyperEditing your craft to orbit. 

Are you re-using the top bit for the different moons and having a disposable lower section for Tylo?

Oh and 5159dV might be marginal. I'd personally go for more like 5700. 

Edited by Foxster

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Using an standard lander for the other moons and an Tylo drop stage makes sense, something who can land and return from Vall can take off from Tylo if you have good twr

one option might be to make an mining ship, drill and the small ISRU, this gives you an SSTO who is nice if you plan multiple landings, its also nice for moving around in the Jool system. 
Downside is that mining with the small isru is slow.

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My Tylo figures were 3150m/s to land, 2700m/s to get back to orbit. I would budget a minimum of 2400m/s for Vall (I used 1200 down, 970 up).

As Tylo ascent is fairly similar to a round trip on Vall in delta-v terms, I've always (well, both times) designed a lander that could easily do Vall (and the outer moons with mostly-empty tanks) then stuck a Tylo descent module on the bottom. That'll get disposed of or left behind.

I tried two options: one where the descent module landed (required legs and lots of ladders; EVA packs will not get you back up to the upper module!) and one where the descent module was dropped at the last moment, the main lander taking over for touchdown (made the descent module easier to design as I could use a bigger engine without worrying about ladders, but meant the actual lander needed a little more fuel and the switchover occurred at the scariest point of the landing). Neither was perfect.

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10 hours ago, Foxster said:

Tylo is hard to land and return on so, if you aren't already, I'd suggest "trying it in the simulator" first by HyperEditing your craft to orbit. 

Are you re-using the top bit for the different moons and having a disposable lower section for Tylo?

Oh and 5159dV might be marginal. I'd personally go for more like 5700. 

Yes, The top stage will be used for landing on Vall, Bop, and Pol (The bottom stage can be changed out with a turbojet for Laythe) 

Ill also probably add a bit more fuel to make it around 5300 or so.

 

8 hours ago, magnemoe said:

Using an standard lander for the other moons and an Tylo drop stage makes sense, something who can land and return from Vall can take off from Tylo if you have good twr

one option might be to make an mining ship, drill and the small ISRU, this gives you an SSTO who is nice if you plan multiple landings, its also nice for moving around in the Jool system. 
Downside is that mining with the small isru is slow.

Since i'm doing a Jool 5 challenge, i'm not going to use ISRU (Because its easy to do that :wink:)

Edited by Starslinger999

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Perhaps I'm a bit late, but here are my tips based on my own Jool 5 Challenge (see the link in my sig for the full report; mind you that this was pre-1.0).

From my notes, I see that landing took 2529 m/s, while takeoff required 2364 m/s (plus 26 m/s for rendezvous with my tug in orbit). The Tylo lander had a total delta-v of 6231 m/s, so I had plenty of margin (I overengineered it a bit).

As for TWR, the landing and takeoff stages never went below a Tylo TWR around 2, while the last stage (starting halfway through ascent) had a slightly lower TWR of 1.7. The most important part is the landing TWR; I'd suggest you don't go below 2 for that.

This is the Tylo lander that I used, a one-man three-stage asparagus design:

ABVDnQmm.jpg

Two of the four side tanks/engines were jettisoned during descent (after spending about 1200 m/s):

DUCmuWGm.jpg

This is what it looked like landed on the surface:

RzGnOV0m.jpg

Takeoff started on three engines,

kaAVqsYm.jpg

and the two side tanks/engines were jettisoned midway through, with only the central stack reaching orbit:

xrdDWywm.jpg

Edited by Meithan

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I'm playing around with a Tylo SSTO design for a Grand Tour mission.  This ugly mess seems to work:

x7YcYuR.png

The core is a 4000m/s low-grav hopper with a Terrier and all the science bits. The side aerospike boosters get docked in place with a small claw tug (can store all 4 in the 4-space Mk3 cargo bay - actually the whole Grand Tour mission has to fit in cargo bays on the mothership). By itself, the mini docking port is a floppy mess.  But with the retracting landing gear and their invisible auto-strut feature on both sides of the docking ports, this thing is solid as a rock when docked up (this feature may go away in future versions).

Testing with hyperedit, I found that mechjeb's landing module requires about 2600m/s for an equatorial landing.  Piloting by hand with really terrifying suicide burns gets ~2400.  The initial TWR of 1.76 is a bit low for comfort but it's doable, it climbs to about 3.5 by touchdown.

Edited by fourfa

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