Eve SSTO: any possible ways?

[Cunjo Carl]

2 minutes ago, GoSlash27 said:

Cunjo Carl,

 You wouldn't happen to be from Pittsburgh, would you? "Slippy" is a Pittsburgh thing...

Go Stillers,
-Slashy

Nah, I'm from California, but I have a revolving-door office in a university so I pick up mannerisms from all over without realizing it. Nice to know where 'slippy' came from! Now I just need to track down 'schmutz'.

I love the robot wars avatar by the way- It practically got me into engineering... Or, wait he's too young for that. Smeg! it's nice to see another Red Dwarf fan.

[Sharpy]

Okay, let me chime in with something that is likely a dead alley but may be a chance.

The plane linked obviously won't work, but the general concept might: start the nuke at altitude high enough. Keep climb profile flat enough. That tiny plane took nearly 20 minutes to reach orbit on Kerbin - with climb angle of about 3 degrees. Slowly gain altitude, slowly reduce air drag, slowly gain speed, slowly reduce gravitational drag... it would start the nuke from about 20km, and 1000m/s, and cover the whole climb to orbit from there on it and nothing else. It also didn't really need that 1000m/s, but it definitely needed altitude over 10km and speed sufficient to maintain the minimal climb and the minimal acceleration despite hauling the (useless by then) Whiplash to orbit.

In short, a Kerbin orbit on nuke alone from standstill at 10km should be possible.

How about Eve? *shrug* Just tossing an idea.

[Iche_Bins]

How about that craft:

 

Shurely you could implement that one for an SSTO

[Sharpy]

1 hour ago, Iche_Bins said:

 

Shurely you could implement that one for an SSTO

1) requires mods (Infernal Robotics and kOS.)

2) not enough TWR, I believe.

 

OTOH the ladder-based Kraken Drive would work. But if you go that way, alt+F12 is much easier...

[Reusables]

12 hours ago, Sharpy said:

Okay, let me chime in with something that is likely a dead alley but may be a chance.

The plane linked obviously won't work, but the general concept might: start the nuke at altitude high enough. Keep climb profile flat enough. That tiny plane took nearly 20 minutes to reach orbit on Kerbin - with climb angle of about 3 degrees. Slowly gain altitude, slowly reduce air drag, slowly gain speed, slowly reduce gravitational drag... it would start the nuke from about 20km, and 1000m/s, and cover the whole climb to orbit from there on it and nothing else. It also didn't really need that 1000m/s, but it definitely needed altitude over 10km and speed sufficient to maintain the minimal climb and the minimal acceleration despite hauling the (useless by then) Whiplash to orbit.

In short, a Kerbin orbit on nuke alone from standstill at 10km should be possible.

How about Eve? *shrug* Just tossing an idea.

That's the exact strategy I'm using now, which got a propeller-rocket SSTO to the orbit on Kerbin.

During the test, I found that the high gravitation of Eve makes the craft unpractical to fly, as it needs tons of wing surfaces. Also it consumes a lot of fuel. Since the low atmosphere of Eve is very thick, I think it'd be better to have propellers to haul the craft.

+ Now I think that even if eve doesn't have any atmosphere, it'lly be still challenging to make an SSTO, since the DV & TWR requirement is just too big..

50 minutes ago, Iche_Bins said:

How about that craft:

(snip)

Shurely you could implement that one for an SSTO

But it needs kOS, it wouldn't work without the mod. This thread was about stock solution.

Anyway, I'm still trying with the propeller concept even though it'it's nearly impossible. I think hacking gravity by x1.7 on Kerbin will make a reasonable representation for eve ssto. I could get a liftoff on the setup with the props, but I think it isn't able to make any orbit..

[Carl]

Quote

+ Now I think that even if eve doesn't have any atmosphere, it'lly be still challenging to make an SSTO, since the DV & TWR requirement is just too big..

This.

 

Reusable i think can be done with as noted a reusable booster. But single stage is flat out impossible without some kind of propellantless drive which is compact and weight ok.

[magnemoe]

1 hour ago, Abastro said:

That's the exact strategy I'm using now, which got a propeller-rocket SSTO to the orbit on Kerbin.

During the test, I found that the high gravitation of Eve makes the craft unpractical to fly, as it needs tons of wing surfaces. Also it consumes a lot of fuel. Since the low atmosphere of Eve is very thick, I think it'd be better to have propellers to haul the craft.

+ Now I think that even if eve doesn't have any atmosphere, it'lly be still challenging to make an SSTO, since the DV & TWR requirement is just too big..

But it needs kOS, it wouldn't work without the mod. This thread was about stock solution.

Anyway, I'm still trying with the propeller concept even though it'it's nearly impossible. I think hacking gravity by x1.7 on Kerbin will make a reasonable representation for eve ssto. I could get a liftoff on the setup with the props, but I think it isn't able to make any orbit..

Will not the propellers generate too much drag at high speed? The stock propels I have seen is huge. 
You could add mass to simulate the higher gravity, you also need an higher orbital speed on Eve. 

Has played a bit with mod propellers on Eve, main issue is that you still need an decent sized rocket to reach orbit making the propeller first stage more complex than an larger rocket. 
 

[Sharpy]

1 hour ago, magnemoe said:

Will not the propellers generate too much drag at high speed? The stock propels I have seen is huge.

You're a couple pages late with that concern

Quote

You could add mass to simulate the higher gravity, you also need an higher orbital speed on Eve.

Doesn't quite work because it becomes both gravitational mass (dragging you down) and inert mass (reducing acceleration in horizontal flight), and while the former vanishes to zero with waning gravitational drag, the latter stays with you all the way to the orbit. Plus the worst part of the simulation is the atmosphere. You can Alt+F12 the gravity, but not pressure. and not the scale height - if you assume Kerbin ground level to be Eve's 10km or so, you still have 70 vs Eve's 80km to climb left. and corresponding heating problems.

[Zeiss Ikon]

Hmm.  With the high atmospheric pressure down there, I wonder if you couldn't use what I'm used to thinking of as a "proppy-copter" design (propellers pushing a helicopter style rotor around) to get initial altitude, merged with a "Roton" or "Nurflugel" type rotary wing/rocket combination once you get into thin enough air for a rocket to work reasonably well.  The rotary wing converts even a little rocket thrust intoa great deal more lift-based thrust from a rotor, multiplying your Isp in much the same way jet engines and augmentor ducts (not modeled in KSP, as far as I know) do.  The tradeoff is that the Roton platform is a PITA to fly in hover, but the original Nurflugel (see Luftwaffe 1946) was intended to use the rotor mainly for VTO and rapid climb.  As speed builds, the collective pitch is increased to control rotor rpm, until eventually the rockets are thrusting almost completely forward (originally, there would always have been some spin, as the centrifuge effect acted as the high pressure fuel pump for the tiny rocket chambers).

[Reusables]

10 hours ago, magnemoe said:

Will not the propellers generate too much drag at high speed? The stock propels I have seen is huge. 
You could add mass to simulate the higher gravity, you also need an higher orbital speed on Eve. 

Has played a bit with mod propellers on Eve, main issue is that you still need an decent sized rocket to reach orbit making the propeller first stage more complex than an larger rocket. 

Unlike the mod propellers, it's possible to have them streamlined to the airfloworld with authority in deploy mode. In my experience, the props give less than 2kn when the drag of the whole plane is over 50kn.

Still, the mass penalty seems to be very big, so it's nearly impossible to have them as SSTO.

9 hours ago, Sharpy said:

Plus the worst part of the simulation is the atmosphere. You can Alt+F12 the gravity, but not pressure. and not the scale height - if you assume Kerbin ground level to be Eve's 10km or so, you still have 70 vs Eve's 80km to climb left. and corresponding heating problems.

I know that it'should different, but it's easier to test on Kerbin with the hacked gravity. I think the hardness is approximately same.

2 hours ago, Zeiss Ikon said:

Hmm.  With the high atmospheric pressure down there, I wonder if you couldn't use what I'm used to thinking of as a "proppy-copter" design (propellers pushing a helicopter style rotor around) to get initial altitude, merged with a "Roton" or "Nurflugel" type rotary wing/rocket combination once you get into thin enough air for a rocket to work reasonably well.  The rotary wing converts even a little rocket thrust intoa great deal more lift-based thrust from a rotor, multiplying your Isp in much the same way jet engines and augmentor ducts (not modeled in KSP, as far as I know) do.  The tradeoff is that the Roton platform is a PITA to fly in hover, but the original Nurflugel (see Luftwaffe 1946) was intended to use the rotor mainly for VTO and rapid climb.  As speed builds, the collective pitch is increased to control rotor rpm, until eventually the rockets are thrusting almost completely forward (originally, there would always have been some spin, as the centrifuge effect acted as the high pressure fuel pump for the tiny rocket chambers).

VTOL is much harder, as the props have TWR less than 4 even in the dense atmosphere. Also rocket powered props will be less efficient than rocket itself in ksp, if this is what you meant.

[GoSlash27]

I think it's safe to say that the idea of an Eve SSTO is a pipe dream as of 1.2.2. Even if it is *technically* feasible, it's still totally impractical in a career game.

Sorry,
-Slashy

 

Edited January 24, 2017 by GoSlash27
edited by the department of redundancy department

[Zeiss Ikon]

9 hours ago, Abastro said:

VTOL is much harder, as the props have TWR less than 4 even in the dense atmosphere. Also rocket powered props will be less efficient than rocket itself in ksp, if this is what you meant.

The idea of a "proppy-copter" is to use propeller(s) to drive a rotary wing.  Drag is (somewhat) less than it would be with an airplane, because only the wing need move fast enough to create lift, and this extends well to the "monocopter" design, which substitutes a counterweight (possibly including the electrical power plant, in our case) for the second blade.  This does work; it's been done a few times in real-world helicopter design when "simple" and "cheap" were high on the priority list, and there are many model monocopter designs that use a small engine to drive the rotation.  It's possible for a real-world proppy-copter to be minimally flyable with a single pilot on board and fewer than twenty horsepower -- neither a conventional helicopter nor an autgyro can fly with that little power.

[Reusables]

2 hours ago, Zeiss Ikon said:

The idea of a "proppy-copter" is to use propeller(s) to drive a rotary wing.  Drag is (somewhat) less than it would be with an airplane, because only the wing need move fast enough to create lift, and this extends well to the "monocopter" design, which substitutes a counterweight (possibly including the electrical power plant, in our case) for the second blade.  This does work; it's been done a few times in real-world helicopter design when "simple" and "cheap" were high on the priority list, and there are many model monocopter designs that use a small engine to drive the rotation.  It's possible for a real-world proppy-copter to be minimally flyable with a single pilot on board and fewer than twenty horsepower -- neither a conventional helicopter nor an autgyro can fly with that little power.

I took wrong assumption of less Isp in spite of its better TWR. So what you meant was about rocket propelled turboprops? Then, what rocket engine would be the best?

[gilflo]

I know this is not stock but maybe some of you would have a look

 

[Reusables]

1 minute ago, gilflo said:

I know this is not stock but maybe some of you would have a look

 

It appeared in this thread couple of times, so it'should pretty well known.

Also this thread is about stock feasibility...

[Zeiss Ikon]

9 hours ago, Abastro said:

I took wrong assumption of less Isp in spite of its better TWR. So what you meant was about rocket propelled turboprops? Then, what rocket engine would be the best?

Actually, I used the wrong word for the rocket version -- Nurflugel is a tailless airplane, while I was actually thinking of Treibflugel, which is a rocket-powered helicopter/airplane hybrid (like a fighter/interceptor version of Roton, which Scott Manley has built as a hovering machine, at least).  Change out the rockets at the tips for small propeller engines about 1/3 out the rotor, and you get a proppy-copter.  Build a ship with both proppy-copter (for taking off from the soup) and Treibflugel rotors, and you should be able to take off from Eve's surface, get high enough for the rockets to work, and then use the rocket/rotor to get high enough for direct rocket propulsion to finish the job.  Whether you can gain enough from the rotors to actually lift the whole ship into orbit as an SSTO, I can't tell you (I suspect not, but the mathematics to optimize the machine are beyond me), but at the very least, it should be capable of acting as the reusable first stage folks have talked about, even starting from Eve sea level.  And I'm pretty sure you can build something like it in the stock game, since I've seen multiple claims of stock helicopters.

[Reusables]

1 hour ago, Zeiss Ikon said:

Actually, I used the wrong word for the rocket version -- Nurflugel is a tailless airplane, while I was actually thinking of Treibflugel, which is a rocket-powered helicopter/airplane hybrid (like a fighter/interceptor version of Roton, which Scott Manley has built as a hovering machine, at least).  Change out the rockets at the tips for small propeller engines about 1/3 out the rotor, and you get a proppy-copter.  Build a ship with both proppy-copter (for taking off from the soup) and Treibflugel rotors, and you should be able to take off from Eve's surface, get high enough for the rockets to work, and then use the rocket/rotor to get high enough for direct rocket propulsion to finish the job.  Whether you can gain enough from the rotors to actually lift the whole ship into orbit as an SSTO, I can't tell you (I suspect not, but the mathematics to optimize the machine are beyond me), but at the very least, it should be capable of acting as the reusable first stage folks have talked about, even starting from Eve sea level.  And I'm pretty sure you can build something like it in the stock game, since I've seen multiple claims of stock helicopters.

You mean rockets on the propeller fins? That's the traditional type of propellers in ksp. Since the propulsion happens on the rotor, it's unstable, hard to control and tend to have heavy rotor for the fuel. Also effective Isp on rocket mode gets smaller due to its tilted thrust, which is critical for chemical rockets to get high enough. On the other hand, turboprops with elevons would be better in the efficiency and stability.

Edited January 25, 2017 by Reusables
Forgot to add more sentences

[Carl]

Quote

and tend to have heavy rotor for the fuel.

This tends to be the real issue, because we don't have a true rotation capable part it's impossible in stock to take the weight off the prop which kills it's efficiency. 

[Reusables]

10 minutes ago, Carl said:

This tends to be the real issue, because we don't have a true rotation capable part it's impossible in stock to take the weight off the prop which kills it's efficiency. 

This. (And also there's the control issue, which is not really an issue on the real world counterpart)

To add, there are reliable stock hinges which can have light high-speed rotors to haul heavy stators, but heavy rotors will simply be broken due to the fragility of the hinge.

[StrandedonEarth]

Oh look, another Eve thread...

Sorry, I can't resist posting this when someone mentions ascending from Eve

[Kergarin]

5 hours ago, StrandedonEarth said:

Oh look, another Eve thread...

Sorry, I can't resist posting this when someone mentions ascending from Eve

Last time I proved this wrong 

Still not sure about this time  my best ascends are still 200-300m/s short

[Reusables]

I found that shorter elerons for propeller wings provide better thrust. So If I allow higher part count or accomodate better design, propellers with TWR over 4 on high speed would be possible.

Also, I managed to get this to fly. (This does not mean it will capable of orbit)

http://imgur.com/a/fVk2F

 

Edited January 25, 2017 by Reusables

[Kergarin]

1.2.2 can't hold us down on Eve!!

It has been done again!

At least an unmanned SSTO launched from the highest mountain. (Landed by hyperedit)

Hope i can post a Video tomorrow, and afterwards we need some upscaling to make it manned again

[Carl]

Well Dang. Very interested to see how you did it.

Edited January 26, 2017 by Carl

[Kergarin]

7 hours ago, Carl said:

Well Dang. Very interested to see how you did it.

It's more simple than I thought. basically it's two of my 1.1.3 unmanned SSTOs strapped together, a really flat gravity turn, and a carefull finger on the throttle.

I can't imagine, that the reason this works is just because I'm saving the weight of one 0.03tons nosecone compared to the single body rocket. It feels like there is an aerodynamic advantage by strapping them together. 

I'm at work right now, but will post details later, as soon as I find the time.

Edited January 26, 2017 by Kergarin