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Duna electric plane


MAFman
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I spent some time trying to make a propeller-driven SSTO plane that could operate on Duna and ended up scrapping the idea, mostly because the operational ceiling on Duna is too low for the props to make much of a contribution. Just making something that can take off and land on props is not so tough however.  Just keep it light and have lots of wing area. As to how to get it there,  landing it from orbit  should not be a problem. It's putting enough engines and tanks on it so that it can get back to orbit and still fly reasonably on props that's pretty tough.

Edited by herbal space program
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1 hour ago, OHara said:

The Dunasoar family (link to kerbalx) are examples of planes and their lifter, that will likely inspire you.

The rotors for the propellers are more complicated than you will need if you use the Breaking Ground mod.  (Dunasoar was made before Breaking Ground appeared.)

How do you make those rotors without the BG DLC??

 

(edit)...So each propeller is a separate craft that you undock into some kind of cage and then switch to and spin up with reaction wheels? Boy that must have been hard to get working. I'm impressed!

Edited by herbal space program
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Let´s recapitulate:

Duna has less atmosphere and less gravity than Kerbin. So you need very little thrust, but a whole lot of surface area to stay aloft. Oh, and the terrain is a little difficult for long take off runs. Let´s keep that in mind, too. Something like this works:

9LEUFY8.png

I found that if my designs could barely take off on Kerbin than they were probably right for Duna. Oh, and reducing the Prop RPMs a little bit works wonders. 

Have fun designing and show us your results pls ;p

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8 hours ago, herbal space program said:

So each propeller is a separate craft that you undock into some kind of cage and then switch to and spin up with reaction wheels? Boy that must have been hard to get working. I'm impressed!

This was sort of a standard thing back before BG... I had those working too. I don't know who "invented" them though, but it was a widely shared idea.

Spoiler

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(its a modded duna, scaled up, with oceans)

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It could cover quite some distance in a reasonable time at 100+ m/s, although on a 3x Duna, progress was slower:

7neEP27.png

 

 

4 hours ago, KerrMü said:

Let´s recapitulate:

Duna has less atmosphere and less gravity than Kerbin. So you need very little thrust, but a whole lot of surface area to stay aloft. Oh, and the terrain is a little difficult for long take off runs. Let´s keep that in mind, too.

Which is why I tend to make tilt rotors. Incidentally, just stopping the rotors in horizontal mode allows them to act like wings (a prototype helo did this in real life (the Sikorsky S-72)

Spoiler

Sikorsky_X-wing_diagonal_view.jpg

Most of my tilt-rotors use the ducted fan blades, like so:

Spoiler

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^those were with prop blades, then the next update had the ducted fan blades, and I made the tilt rotor even better on Kerbin^

sOkgIWq.png

Quite fast, nearly supersonic, flying on a 3x rescale of kerbin (only 1.25x atmosphere height rescale), but for these atmospheric craft, that's not really relevant, except the distances to cross are greater.

but to lift my desired payload on Duna (or was it a modded duna, with 1.2533x gravity modifier, for 0.376G like mars instead of 0.3G), I needed more surface area:

Spoiler

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When trying to lift heavy payloads (36-40 tons) at high altitude, I was unable to transition to forward flight by tilting the rotors forward. So I tried to make a compound helo instead of tilt rotors, and kept the rotors horizontal while adding some fans just for forward propulsion... results... weren't that good, even after I reduced payload mass (not the half full fuel tanks):

CJGnUEH.png

but it worked reasonably well at lower altitudes:

Sg3P8MY.png

At high altitude, I was at least able to lift off in a hover, fly around the launchpad, and land back on the launch pad, but handling was not great.

1czRsd5.png

PJnIAcA.png

 

 

 

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15 hours ago, herbal space program said:

It's putting enough engines and tanks on it so that it can get back to orbit and still fly reasonably on props that's pretty tough.

Well, that's an entirely different beast. The designs that I showed were just for moving around Duna... getting to orbit of Duna was an entirely different proposition.

19 hours ago, MAFman said:

how do I get it to Duna?

Well, when attempting to get a non-SSTO plane to obit, I have a few options.

(note: these are all on a 3x rescale Kerbin, so its easier and craft can be smaller in stock)

#1, piggy back it on  larger SSTO

Spoiler

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#2) Sling it under a spaceplane:

Spoiler

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^In this case, the bigger plane doesn't reach orbit, but the cargo puts itself into orbit in time to switch back to the large plane before it falls back into the atmosphre^

#3) Stick it on top of a big rocket, put big fins on the big rocket to counteract the wing area up top, go higher before tipping over into the gravity turn( = less air, and CG shifts farther forward as lower stage fuel is burnt off)

Spoiler

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#4) If it has a rocket of its own (such as many of my cargo planes meant to be SSTOs on Duna, but not Kerbin), strap it on top of a big booster, Space-shuttle style, and have fun with differential throttling:

Spoiler

P9hUZ1l.png

Once in orbit, you can keep it attached to an booster rocket it may have had, use its own on board propulsion, use a tug, etc to get it to Duna.

In the case of my electric prop cargoplanes, on option is to have a rocket stage in the cargo bay, that will be left in low duna orbit as a space tug.

Spoiler

3Ic0rMq.png

In this case, once the electric plane reaches duna (or Eve, or wherever it is meant to go with modded systems), it stays there, and just flies around, it doesn't come back.

In stock systems, its fairly easy to make a "module" for the cargo bay that can turn it into an SSTO for its destination, and allow it to get back to space

Such as way back when, with my Laythe plane that only had panthers:

Spoiler

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15 hours ago, Dr. Kerbal said:

A Duna PLane!? Ya. Im sure its possible if you have enough wingspan and thrust. 

Making a regular SSTO plane that can fly to Duna and back is actually pretty easy because the low surface pressure and gravity make it possible to take off on just Nervs.  The main thing is just to have a lot of wing area:

grjADrA.png

I also found it helpful to mount drogue chutes on the trailing edges of the wings for landing, to mitigate against the high stall speed and the tendency to bounce in the low gravity:

XqIuRVB.png

Edited by herbal space program
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49 minutes ago, herbal space program said:

Making a regular SSTO plane that can fly to Duna and back is actually pretty easy because the low surface pressure and gravity make it possible to take off on just Nervs.  The main thing is just to have a lot of wing area:

grjADrA.png

I also found it helpful to mount drogue chutes on the trailing edges of the wings for landing, to mitigate against the high stall speed and the tendency to bounce in the low gravity:

XqIuRVB.png

Awesome plane! I have only made SSTOs that can get to LKO and Minmus. 

13 hours ago, KerrMü said:

Let´s recapitulate:

Duna has less atmosphere and less gravity than Kerbin. So you need very little thrust, but a whole lot of surface area to stay aloft. Oh, and the terrain is a little difficult for long take off runs. Let´s keep that in mind, too. Something like this works:

9LEUFY8.png

I found that if my designs could barely take off on Kerbin than they were probably right for Duna. Oh, and reducing the Prop RPMs a little bit works wonders. 

Have fun designing and show us your results pls ;p

Awesome plane! I can never figure out propellers. But the good thing is that i know how to land planes on mountains. Long story short. I always miss the KSC

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