Massive Duna Ship help

[Gus Grizzom]

Hello fellow Kerbalnauts,

I'm playing on the PS4 so sadly no mods to help me calculate things for my problem. No more

So I'm constructing a massive Duna ship ( think Discovery from 2001)

It is being built in a 90 orbit of Kerbin.

The total dry mass of the craft is 70 tons. 55.2 m in length

I'm planning on using nuclear engines to power it. My question is how much fuel do I need, to leave LKO and get to Duna ( planning launch during Duna Kerban close approach) 

My craft has currently 3 empty Kerbodyne 7200 

1 Kerbodyne 3600 and a Rockmax X200-16, all empty.

 

Please let me know how I achieve my goal.

 

Cheers,

Gus Grizzom

 

[Vanamonde]

Thread moved to Gameplay Questions. 

What you're going to need to do is figure the rocket equation semi-backwards to start from the goal and arrive at the initial conditions needed. I did the algebra for that a while back, and I will share it if I can find it. (Or figure it out again.) If not, some helpful person will be along shortly.  

[RatchetinSpace]

Welcome to the forums!

1 problem. Nuclear engines run on only liquid fuel, no oxidiser, so your craft won't have optimal dry mass with your chosen fuel tanks. That said, the craft should have plenty of delta V if fully fueled. Those fuel tanks you listed total 12,060 L of liquid fuel, equal to 60.3 tonnes of fuel (no oxidiser). Plugging it into the rocket equation with nuclear engines you get 4881 m/s delta V.

Now I'm not entirely clear as to what your mission profile looks like. Are you just going for a flyby or do you want to slow down at Duna as well? If so, what orbit are you aiming for? Do you intend to return to Kerbin afterwards?

For a simple flyby, 4881 m/s would be overkill. If you want to flyby Duna, then get back to LKO I'd budget 2800/s just to be safe, so you'll need 6000 L of liquid fuel.

If you intend to stay at Duna you'll have to slow down. You can do this through aerobraking but that can be risky if you don't have a heat shield. If you want to slow down propulsively, budget 1800 m/s (1000ish to leave Kerbin and 800ish to slow down). Then to return again you'll need 1800 again, for a total of 3600 m/s, meaning your craft needs 8138 L of liquid fuel.

My best advice for going interplanetary, budget loads of fuel and quick-save often. You may not find yourself on the optimal trajectory and find you have to waste loads of fuel getting back on track. If you have the time, I'd recommend just filling your ship to the brim. From the sounds of things, your ship should be good to make the journey.

[GoSlash27]

1 hour ago, Vanamonde said:

If not, some helpful person will be along shortly.  

So what we do is this:

Assuming we are following precisely your mission plan, we need to get from low Kerbin orbit to low Duna orbit. I don't know how you plan on getting back, but the calculation process is identical... According to the map , DV to get to LDO is 1,700 m/sec. You didn't say you're aerobraking, so I'm assuming you're not.

We divide that by g0; 9.81 m/sec² = 173.35

We then divide that by our LV-N's specific impulse of 800 sec, which equals 0.2167.

We then raise e to that power. e^(0.2167) = 1.242

Our wet to dry mass ratio is 1.242. That is; our ship plus fuel mass is 1.242 times our ship mass without fuel. Converting that to a less- confusing value, (1.242-1) = .242; Our fuel is 24.2% the mass of the ship when dry.

Your ship's dry mass is 70 tonnes. That means you need 24.2%* 70 tonnes of fuel, which is 17 tonnes.

200 units of fuel is 1 tonne, so you need 200*17=3,400 units of fuel.

As a sanity check: Your ship weighs (70+17)= 87 tonnes when loaded, and 70 tonnes when dry. 87/70=1.243 wet to dry ratio.

ln(1.243)= .217.
* 9.81= 2.133
*800sec= 1,706 m/sec DV.

Again... this is only enough fuel to get you from LKO to LDO without aerobraking. You will arrive in LDO out of gas. If you need to do more (or less) than this, then figure out exactly what your DV budget is, then apply the same process to find your fuel quantity.

HTHs,
-Slashy

 

 

 

 

 

 

Edited April 17, 2018 by GoSlash27

[Gus Grizzom]

Hey RachetinSpace,

 

Thanks for the speedy reply.

Mission profile is to orbit Duna, send down lander. 

The lander is configured for both desent and ascent. It is equipped with parachutes, aero brakes ( redundancy). I will have enough fuel for both phases.

Then Conduct ground mission and return to the mothership so to speak. I will ditch the lander in orbit ( so I can refuel and reuse later)

After all that return to Kerbin. I know that I need less Delta v for the return trip so I should have enough fuel for the trip and course corrections.

 

Thanks again for all your insight, it's hard on console with no Kerbin engineer!

 

Regards,

Gus Grizzom

[bewing]

1 hour ago, Gus Grizzom said:

it's hard on console with no Kerbin engineer!

Well, really, that's what the whole concept of "reverting" is about. You launch your ship, fly the mission to Duna, land your lander, and fly back up to your mothership. Then you revert the flight.

If it worked the first time, then the second time you do it for real. If there was anything you forgot the first time (or if you didn't have enough fuel) -- you fix it, and do another trial run.

Flying everything twice just make it twice as much fun, right?

(Yes you have to be careful not to switch focus away from the current craft.)

 

Edited April 18, 2018 by bewing

[GoSlash27]

2 hours ago, Gus Grizzom said:

After all that return to Kerbin. I know that I need less Delta v for the return trip so I should have enough fuel for the trip and course corrections.

Guz Grizzom,

 You need exactly the same DV to get home as you did to get out there. Are you planning on aerobraking at Kerbin? If not, then that's another 1,700 m/sec DV that we need to account for. The process is exactly the same as described above, but the fuel requirement will be wildly different.

You must first define the mission of a stage. What's it's payload? Minimum acceleration? total DV budget? You can design the stage only after you have answered these questions.

Best,
-Slashy

 

[Gus Grizzom]

50 minutes ago, bewing said:

37 minutes ago, GoSlash27 said:

Guz Grizzom,

 You need exactly the same DV to get home as you did to get out there. Are you planning on aerobraking at Kerbin? If not, then that's another 1,700 m/sec DV that we need to account for. The process is exactly the same as described above, but the fuel requirement will be wildly different.

You must first define the mission of a stage. What's it's payload? Minimum acceleration? total DV budget? You can design the stage only after you have answered these questions.

Best,
-Slashy

 

 

Slashy,

 

My payload is the Craft plus the LAAM ( landing and ascent module) both at the time of launch from LKO will be docked together. Since the only the LAAM will be landing on Duna. The main craft will encounter Duna at a high orbit and gradually lower the orbit of the main craft till it's in a parking orbit that the LAAM can intercept ( roughly 50km ) 

 

Once my ground mission is on Duna is over. The LAAM with redock with the main craft to transfer crew. Once a launch window is established back to Kerbin, the LAAM with undock and remain hopefuly in Duna's orbit ( ready to be reused at a later mission) 

Now I have preformed a similar mission to the Mun. Assembled large craft in orbit, fueled it in orbit and launched to the Mun. I just think it's time to up the ante with this ridiculous mission to Duna.

Again thanks for all the help!

 

Regards,

Gus Grizzom

 

[GoSlash27]

Gus Grizzom,

What's the mass of the LAAM? What's the dry mass of the ship without the LAAM?

Best,
-Slashy

[Curveball Anders]

10 hours ago, bewing said:

Well, really, that's what the whole concept of "reverting" is about.

When trying something new and complex I sometimes take the 'reverting' strategy full out.

Often using a copy of my current career save renamed 'simulation'

When I designed my first Duna return mission I started with the return capsule, debugging it to orbit, deorbited and tweaked until good.

Then added the home transfer part, including the return capsule, debugging it to Duna orbit and returned to LKO.

Iterating each step until good, adding the next and working all the way back to the initial launcher.

It took time, but quite fun and I learned a lot during each step.

[Gus Grizzom]

5 hours ago, GoSlash27 said:

Gus Grizzom,

What's the mass of the LAAM? What's the dry mass of the ship without the LAAM?

Best,
-Slashy

Slashy,

The main craft dry mass ( unfueled besides monoprop free) is 62 tonnes. The LAAM fueled for descent and ascent is 18 tonnes.

 

Cheers,

Guz Grizzom.

[Gus Grizzom]

3 hours ago, Curveball Anders said:

When trying something new and complex I sometimes take the 'reverting' strategy full out.

Often using a copy of my current career save renamed 'simulation'

When I designed my first Duna return mission I started with the return capsule, debugging it to orbit, deorbited and tweaked until good.

Then added the home transfer part, including the return capsule, debugging it to Duna orbit and returned to LKO.

Iterating each step until good, adding the next and working all the way back to the initial launcher.

It took time, but quite fun and I learned a lot during each step.

Curveball,

Absolutely, I took page out of NASA's book when starting this project. 

I first built a similar system half it's size and sent it to the Mun back, just to get good at the mechanics of multiple part craft.

Then I built the massive vessel in the VAB, broke it down into subassemblies. Launched those into orbit. Tested them and their redundancy systems. Once I linked the main module ( so to speak) with the service core, I repeated the process. 

With my LAAM module I tested it only on the Mun. I had enough ∆v to go to the Mun on it's own from LKO land and ascend and return to LKO. Now I know it's not the same as Duna. Perhaps I'll send it out to Duna first and see how it handles the mission parameters.

At this point I'm scratching my head with the propulsion drive section.

It currently has 4 NERV's on it with the fuel capacity of 16,020 units of fuel. 

Now I'm thinking since it will take time to from 100km Kerbin orbit to accelerate to escape Kerbin gravity and into an optimal Trans Duna injection. 

So I have the option of  adding on  4 Poodle engine boosters to the drive section to help with that initial speed up for Duna. 

Fun stuff I enjoy these ambitious type missions cos it makes you really think especially on console with no engineer mods or ∆v calculator's. This makes you appreciate the men and women who worked and work on space programs.

 

Cheers,

 

Gus Grizzom

[Gus Grizzom]

Here is a picture of the beast. The LAAM is docked at the bottom, it's in position for a Duna descent. During the voyage it will be docked perpendicularly to the main craft.

 

https://drive.google.com/file/d/1-noZwngPDCW7LyV30s04HL9CwkIufFDv/view?usp=drivesdk

[GoSlash27]

1 hour ago, Gus Grizzom said:

Slashy,

The main craft dry mass ( unfueled besides monoprop free) is 62 tonnes. The LAAM fueled for descent and ascent is 18 tonnes.

 

Cheers,

Guz Grizzom.

Gus Grizzom,

 Now we're cookin' with gas.

Do you plan on aerobraking at either end?

Best,
-Slashy

[Gus Grizzom]

 

2 minutes ago, GoSlash27 said:

Gus Grizzom,

 Now we're cookin' with gas.

Do you plan on aerobraking at either end?

Best,
-Slashy

Hey Slashy,

The only craft that will aero brake is the the LAAM. I'm planning on a high orbit of 60-70 km of the main craft. Then dropping the LAAM, as it will have the same relative velocity as the main craft I will slowly de-orbit to 50km and then begin aero breaking.

The LAAM has 5 Terrier engines full, RCS,ASAS, 6 chutes, and Air breaks. 

Fingers crossed.

Cheers,

Gus Grizzom

[Snark]

46 minutes ago, Gus Grizzom said:

So I have the option of  adding on  4 Poodle engine boosters to the drive section to help with that initial speed up for Duna.

One handy technique for dealing with launching low-TWR, high-dV craft efficiently from low orbit is periapsis kicking.

In other words, don't try to do the whole burn at once.  Just do a burn of a couple of minutes, which raises your Ap somewhat... then stop.  Coast around one orbit, and then do another burn at Pe that raises your Ap further.  Then again, and again, until you've raised your Ap up fairly high (i.e. several thousand kilometers) and there's not much more dV left until escape velocity.  Then do one final burn at Pe to send you on your way.

This is nice because it allows you to do your burning at low altitude (thus preserving maximum Oberth benefit, so you need the least dV), and also to do all your burning with your high-Isp engines (thus getting the most dV out of your craft).

If I'm reading your numbers right:

• You've got 4 LV-N engines, pushing a craft that's 62 tons dry mass, plus 80 tons of liquid fuel, plus an 18-ton fully-fueled lander.  So the whole shebang has a total fueled mass of 160 tons.
• From a 90 km orbit, your ejection burn to Duna for an ideal window will be 1049 m/s.
• That means you'll need to burn almost exactly 20 tons of fuel for your ejection burn.
• Given the fuel consumption rate of LV-Ns, that means your total burn duration will be 654 seconds, i.e. just a shade under 11 minutes.

So, for example, you could do an initial 2-minute burn, then coast around for another pass to do another 2-minute burn, then a 3-minute burn on the third pass... and then on a fourth (and final) pass you do the remaining ~4 minutes of burn.

[Gus Grizzom]

2 minutes ago, Snark said:

One handy technique for dealing with launching low-TWR, high-dV craft efficiently from low orbit is periapsis kicking.

In other words, don't try to do the whole burn at once.  Just do a burn of a couple of minutes, which raises your Ap somewhat... then stop.  Coast around one orbit, and then do another burn at Pe that raises your Ap further.  Then again, and again, until you've raised your Ap up fairly high (i.e. several thousand kilometers) and there's not much more dV left until escape velocity.  Then do one final burn at Pe to send you on your way.

This is nice because it allows you to do your burning at low altitude (thus preserving maximum Oberth benefit, so you need the least dV), and also to do all your burning with your high-Isp engines (thus getting the most dV out of your craft).

If I'm reading your numbers right:

• You've got 4 LV-N engines, pushing a craft that's 62 tons dry mass, plus 80 tons of liquid fuel, plus an 18-ton fully-fueled lander.  So the whole shebang has a total fueled mass of 160 tons.
• From a 90 km orbit, your ejection burn to Duna for an ideal window will be 1049 m/s.
• That means you'll need to burn almost exactly 20 tons of fuel for your ejection burn.
• Given the fuel consumption rate of LV-Ns, that means your total burn duration will be 654 seconds, i.e. just a shade under 11 minutes.

So, for example, you could do an initial 3.5-minute burn, then coast around for another pass to do another 3.5-minute burn, and then on a third pass you do the remaining ~4 minutes of burn.

Snark,

Firstly, amazing info. Second I was going back and forth with using fuel lox engines to for an escape burn. But your plan makes more sense. Start 3 burns at Peace ( using the gravity for that extra nudge) this will would make it more fuel efficient.

Thanks so much!

Cheers,

Gus Grizzom

[GoSlash27]

Okay, so that gives us the info we need to compute your fuel requirement... provided you don't go using those Poodles you just mentioned.

We compute it all backwards, from the end of the mission to the beginning.

For the trip home, your ship is 62 tonnes dry. 1,700 m/sec DV. We compute the fuel as above.

1700/(9.81*800)= 0.2166.

e^(.2166)= 1.242 wet to dry ratio. 0.242*62 tonnes = 15 tonnes of fuel.

For the trip out there, you have your 62t empty ship, the aforementioned 15t of fuel to get home, and the 18t LAAM. 95t.

1700 m/sec DV still translates to the same wet to dry ratio; 1.242. .242*95t= 23t of fuel to get you to Duna.

So all told, 38t of fuel. 1t is 200 units, so 7,600 units.

Best,
-Slashy

 

[Snark]

20 minutes ago, Gus Grizzom said:

The only craft that will aero brake is the the LAAM. I'm planning on a high orbit of 60-70 km of the main craft. Then dropping the LAAM, as it will have the same relative velocity as the main craft I will slowly de-orbit to 50km and then begin aero breaking.

So, how are you planning on getting into orbit once you arrive at Duna?  Using braking thrust from the LV-Ns?

That's certainly doable, if you like.  However... it does use fuel unnecessarily.  You'd need to spend 600 m/s of braking thrust from your LV-Ns to get into circular low Duna orbit.  That's a pretty big chunk of dV that you can almost entirely eliminate by aerobraking to orbit.

Bear in mind that Duna is a very gentle environment for aerobraking-- you're not arriving at super high speed (assuming a good transfer window), and the planet itself has a relatively low escape velocity, which means by the time you arrive at low Duna orbital altitude, you're going at a speed that can easily aerobrake even without heat shields.

So, for example, you could set up your craft so that when it initially arrives at Duna, it has a Pe of something like 20 km, give or take (exactly how high will depend on how heavy and/or draggy) your craft is-- it may be somewhat higher, it may be somewhat lower.  (You only get one shot, so best to quicksave beforehand so you can fine tune it if you get it wrong.)

So, your whole 140-ton assembly comes flying out of the solar system and plows through Duna's atmosphere, slowing it to a speed that puts it into low Duna orbit with a Ap that's as low as you can manage.  Then you coast around to that Ap, decouple the lander (so that it can coast back down into atmosphere and land), and the decoupled orbital stage just does a small burn to lift its Pe out of atmosphere and circularize.

This requires no design changes at all to your ship, and can save you 500 m/s or more of dV.  The only real downside is that it's tricky to get your aerobraking Pe just right, so you'll likely need to go through several cycles of "try it, revert, adjust Pe slightly, try it again."

[Gus Grizzom]

 

7 minutes ago, Snark said:

So, how are you planning on getting into orbit once you arrive at Duna?  Using braking thrust from the LV-Ns?

That's certainly doable, if you like.  However... it does use fuel unnecessarily.  Duna is a very kind environment for aerobraking-- you're not arriving at super high speed (assuming a good transfer window), and the planet itself has a relatively low escape velocity, which means by the time you arrive at low Duna orbital altitude, you're going at a speed that can easily aerobrake even without heat shields.

So, for example, you could set up your craft so that when it initially arrives at Duna, it has a Pe of something like 20 km, give or take (exactly how high will depend on how heavy and/or draggy) your craft is-- it may be somewhat higher, it may be somewhat lower.  (You only get one shot, so best to quicksave beforehand so you can fine tune it if you get it wrong.)

So, your whole 140-ton assembly comes flying out of the solar system and plows through Duna's atmosphere, slowing it to a speed that puts it into low Duna orbit with a Ap that's as low as you can manage.  Then you coast around to that Ap, decouple the lander (so that it can coast back down into atmosphere and land), and the decoupled orbital stage just does a small burn to lift its Pe out of atmosphere and circularize.

This requires no design changes at all to your ship, and can save you 500 m/s or more of dV.  The only real downside is that it's tricky to get your aerobraking Pe just right, so you'll likely need to go through several cycles of "try it, revert, adjust Pe slightly, try it again."

Snark,

I'll try it both ways. I have a few Air brakes on my sturdiest parts of the craft( just as a redundancy  )

However I'm a bit worried since my craft it basically 3 modules connected with Dockingport Sr.'s. it would cause too much cavitation and , snap no more mission. 

Hmm I do have a Sr. Port on the bow of the craft. Perhaps I can couple on a large inflatable heat shield ( flash back to 2010 the movie) 

Or I can. Couple on retro rockets on the bow Dockingport. So many options.

Also given I'm using NERV's my velocity shouldn't be super high. I think I'll be in good shape for aerobraking. And yes I will save often!

 

Cheers,

 

Gus Grizzom

 

11 minutes ago, Snark said:

So, how are you planning on getting into orbit once you arrive at Duna?  Using braking thrust from the LV-Ns?

That's certainly doable, if you like.  However... it does use fuel unnecessarily.  Duna is a very kind environment for aerobraking-- you're not arriving at super high speed (assuming a good transfer window), and the planet itself has a relatively low escape velocity, which means by the time you arrive at low Duna orbital altitude, you're going at a speed that can easily aerobrake even without heat shields.

So, for example, you could set up your craft so that when it initially arrives at Duna, it has a Pe of something like 20 km, give or take (exactly how high will depend on how heavy and/or draggy) your craft is-- it may be somewhat higher, it may be somewhat lower.  (You only get one shot, so best to quicksave beforehand so you can fine tune it if you get it wrong.)

So, your whole 140-ton assembly comes flying out of the solar system and plows through Duna's atmosphere, slowing it to a speed that puts it into low Duna orbit with a Ap that's as low as you can manage.  Then you coast around to that Ap, decouple the lander (so that it can coast back down into atmosphere and land), and the decoupled orbital stage just does a small burn to lift its Pe out of atmosphere and circularize.

This requires no design changes at all to your ship, and can save you 500 m/s or more of dV.  The only real downside is that it's tricky to get your aerobraking Pe just right, so you'll likely need to go through several cycles of "try it, revert, adjust Pe slightly, try it again."

Snark,

I'll try it both ways. I have a few Air brakes on my sturdiest parts of the craft( just as a redundancy  )

However I'm a bit worried since my craft it basically 3 modules connected with Dockingport Sr.'s. it would cause too much cavitation and , snap no more mission. 

Hmm I do have a Sr. Port on the bow of the craft. Perhaps I can couple on a large inflatable heat shield ( flash back to 2010 the movie) 

Or I can. Couple on retro rockets on the bow Dockingport. So many options.

Also given I'm using NERV's my velocity shouldn't be super high. I think I'll be in good shape for aerobraking. And yes I will save often!

 

Cheers,

 

Gus Grizzom

[Kryxal]

An easy way to save delta-v without breaking your rocket is to do a higher-altitude aerobrake, probably engine-assisted, and capture to an eccentric orbit.  After that, take a few passes to carefully lower your apoapsis, you'll have time.

[Snark]

3 hours ago, Gus Grizzom said:

I have a few Air brakes on my sturdiest parts of the craft

Just FYI, you don't actually need them, at least not for braking to orbit.  However, given that you have them anyway, they can be handy in adjusting the braking while it's going on, e.g. "Oh no, looks like I'm not braking enough" <open them> "...oh, now it's too much..." <close them>

3 hours ago, Gus Grizzom said:

However I'm a bit worried since my craft it basically 3 modules connected with Dockingport Sr.'s. it would cause too much cavitation and , snap no more mission.

Nope.  Not a problem.

Bear in mind that docking-port connections are really strong-- basically they're as strong as a regular part joint.  You don't need to worry that the ship will spontaneously undock.  When they're stuck together, they're stuck together hard.  Any forces strong enough to snap the docking link would be strong enough to snap the ship apart anyway.

I believe that they're not quite as stiff as a regular connection, i.e. they can be a bit "bendy" ... but they're bendy the way a spring is bendy, not brittle-so-that-they-snap.

That slightly increased bendiness can sometimes be an issue if, for example, you have a tall stack of docked-together things and you've got an engine at the back end trying to push them at high acceleration-- can cause some "floppy noodle" issues.  But that's not any concern for aerobraking, because during aerobraking you're basically just luggage.

And if you're using the "senior" docking ports, those are fairly stiff in any case.

Also, bear in mind that in terms of the mechanical forces involved, braking to Duna orbit is pretty darn gentle.  You're shedding a total of about 600 m/s of velocity, and you're doing that over the course of a couple of minutes.  Your deceleration is generally under 1 g.

So as long as you build a ship that's strong enough that it doesn't actually fall apart when standing still on the landing pad at Kerbin, it can handle the forces of Duna aerobraking. 

3 hours ago, Gus Grizzom said:

Perhaps I can couple on a large inflatable heat shield

You seriously don't need it.  Like I said, Duna aerobraking is gentle.  Assuming that you hit a good transfer window, you'll be going only about 1500-1600 m/s when you hit Duna atmosphere.  That's very easily survivable, especially since you're not going all the way down to the surface.  You really don't need a heat shield.

So, you don't need to worry about being snapped apart by mechanical forces, and you don't need to worry about getting fried.  Basically, there are just two likely failure modes for aerobraking-to-orbit at Duna:

1. You don't go deep enough (Pe is set too high on approach).  Result:  Not enough braking, and you need to waste rocket fuel braking to stop from flying out into the solar system again.
2. You go too deep (Pe is set too low on approach).  Result:  You brake too much, and go down to the surface instead of to orbit.

The tricky bit is that on Duna it's really finicky-- the altitude difference between scenario #1 and scenario #2 can literally be less than a kilometer.  So you'll probably need quite a few tries (with reverts) to get it dialed in just right.

Other than that, though, it's pretty simple.

 

3 hours ago, Gus Grizzom said:

Or I can. Couple on retro rockets on the bow Dockingport. So many options.

Really don't need 'em.  Your LV-N engines should suffice for any orbital maneuvering around Duna.

3 hours ago, Gus Grizzom said:

Also given I'm using NERV's my velocity shouldn't be super high.

How fast you'll be going when you arrive there has nothing to do with what kind of engines you use.  It's completely determined by,

1. Duna's escape velocity (which is a property of the planet, not of your ship), and
2. the geometry of the interplanetary path from Kerbin to Duna (which is a property of Duna's and Kerbin's orbits, not of your ship)

With a good transfer window, you'll arrive at Duna with a speed of around 1500-1600 m/s when you hit atmosphere, regardless of ship type.

[KingDominoIII]

The first thing that occurs to me is that that thing is going to be a pain to maneuver. The LAAM makes up ~30% of the weight of the craft. Even 10% can cause sway. And the NERVs have no gimbal.

Consider docking the LAAM on the nose of the craft, or at least parallel, on the side.

[Gus Grizzom]

1 hour ago, KingDominoIII said:

The first thing that occurs to me is that that thing is going to be a pain to maneuver. The LAAM makes up ~30% of the weight of the craft. Even 10% can cause sway. And the NERVs have no gimbal.

Consider docking the LAAM on the nose of the craft, or at least parallel, on the side.

On 4/17/2018 at 8:20 PM, bewing said:

On 4/17/2018 at 8:32 PM, GoSlash27 said:

 

 

 

 

Hey KingDominolll,

Yeah, I was thinking about that too. I actually rebuilt upper portion of the LAAM, so it can dock parallel underneath the craft. I could still attached it to bow dockingport. I'll have a few trails in LKO to see what works. Thanks for looking out.

Regards,

Gus Grizzom