Jump to content

Work-in-Progress [WIP] Design Thread


GusTurbo

Recommended Posts

2 hours ago, septemberWaves said:

I am not sure I understand how you are calculating lift here

I'm calculating the ratios of the amount of lift needed to do the same thing under the same conditions in both 1.0x and 3.2x

If you're flying more or less nose-level to the horizon, how much of what's resisting gravity is centripetal acceleration (orbital speed), and how much is from the wings? How does this compare to the equivalent situation at 3.2x. In the first example, I've already designed the craft so that it will fly nose level at 25km at it's maximum airbreathing speed in 1.0x. This is typically specified in lift units/ton of craft.

Let's say I used 0.67 lift units per ton (I just slapped wings on it by gut feel.) The ratio for 3.2x for those conditions is 158%. So to get the same performance I need 0.67 lift/ton * 158% = 1.06 lift/ton (+extra to account for the additional mass of the wings.) In reality, that's more drag and a lower top speed, so it's even worse.

I made up the speeds and heights for examples 2 and 3, but they're not unreasonable. The ratio starts getting REALLY bad. (Also note that gravity changes with height, and it changes much more slowly at a larger scale.) A mitigating circumstance is that we're burning fuel this whole time, so our effective lift/ton IS going up, but probably not fast enough to keep up.

This is all describing a path that slowly spirals up and out into orbit, while increasing our horizontal velocity. The wings are like a rocket thrusting radial out the whole time. The wings trade some drag (fuel) for lift, and they're pretty efficient at it (Lift-to-Drag ratio), but there's a point of diminishing returns. So, if you want to fly a plane to orbit in 3.2x, what you want to do is point your rockets more down to make up for the lack of wing. This is what a lot of people do in 1.0x. Get the plane up to speed and pitch up hard to loft themselves to desired apoapsis using the extra thrust from the rocket. Then they have plenty of time to circularize before they fall again, but they lose efficiency to gravity drag.

Aaand I just realized I should have added Kerbin's rotational velocity to the speeds  (which is probably going to be higher for 3.2x), but I already deleted the spreadsheet.

I formally apologize for the extent to which I just nerded out. :D

Edited by FleshJeb
Link to comment
Share on other sites

Working on the YF-24, pulled the wings further to the back, this configuration needs to be tested because it can't carry as much fuel as type I due to aerodynamics.

What I like about this design is the V-tail and having no outer intakes.

Type II might look bigger in this picture, but that is just a optical illusion.

86wbunn.png

Edited by Triop
Link to comment
Share on other sites

OnPOCds.png

I spent a lazy Saturday building an Il-76 per a request on KerbalX. It was actually an extremely smooth build process, without any major revisions costing time, and it took off on the first try. Two test flights later, it was ready to ship.

Here's the build process, if you're curious: https://imgur.com/a/hFibdM0

I4lbDDu.png

This is the highest part count craft that I've planned on releasing, coming in at 800 parts on the nose. You get a lot of bang for your buck, though. I mean, just look at this thing.

 

 

Link to comment
Share on other sites

1 hour ago, Torn4dO said:

how do you build a fairing without closing it??

You can end fairings on other parts.

As an example you can put a MK2 pod on top, some octagonal struts as extension (and clamp small satelites to it) and at the end the fairing plate. Then when building the fairing, you don't end it in a cone, but on the Mk2 pod.

Another idea is to use fairings to close engines from upper stages. You don't need to stage the fairing, just leave it there.

Link to comment
Share on other sites

2 hours ago, Shadow dream said:

You can end fairings on other parts.

As an example you can put a MK2 pod on top, some octagonal struts as extension (and clamp small satelites to it) and at the end the fairing plate. Then when building the fairing, you don't end it in a cone, but on the Mk2 pod.

Another idea is to use fairings to close engines from upper stages. You don't need to stage the fairing, just leave it there.

Yeah i know that's possible, I just didn't realise that servo used that technique since the fairing passed the engine.

1 hour ago, HB Stratos said:

or just go in the craftfile and delete all unnecessary sections

I'll look into that, any idea if the game would see the fairing as open? I ask because I would like to go eva inside a fairing, I want to build a base using them.

Link to comment
Share on other sites

5 hours ago, Torn4dO said:

I'll look into that, any idea if the game would see the fairing as open? I ask because I would like to go eva inside a fairing, I want to build a base using them.

Open as in nothing at the end? Yup, that would work. I think stratzenblitz abused it for one of his videos

Link to comment
Share on other sites

I am making some good progress on my >400 part stock (no Making History) Saturn V replica recently. I hope that soon I will be able to release it publicly :)

The Lunar Module descent stage now has more accurate legs, which use a very reliable stock hinge design to work as reliably as possible, but this brings the Lunar Module's part count to over 200, so perhaps I will make an alternative version with stock landing legs.

https://i.imgur.com/G1uJ5fz.mp4

This very long term project of mine has been inspired by the best stock Saturn V/Apollo replicas I've seen in this community ( @Majorjim!, @Bubbadevlin, and @EpicSpaceTroll139's, to name a few). Any criticism of the craft from the gif I posted would be sincerely appreciated.
Thank you,
Big Boy :)

Edited by big boy
fixing a link
Link to comment
Share on other sites

49 minutes ago, big boy said:

Any criticism of the craft from the gif I posted would be sincerely appreciated.

Well.... I'd love to see but I am seeing a 404 error on the gif.... 

Link to comment
Share on other sites

3 hours ago, McFlyever said:

Little Preview to my first fully recoverable Falcon 9.... I have to fix a few small bugs but the important thing - landing the Mainstage - is working really well right now!

 

 

 

Very nice work! I do like the homage to the engine layout of the older Falcon 9s and those landing legs are so cool. I do believe, however, that because of the need for abort procedures, dragon capsules do not use external fairings like satellites. Do let me know if I am wrong about this :)

Once again, fantastic craft you've got here.based on my own experience with them, I cannot imagine how hard it must have been to get those legs working.

-Big Boy

Link to comment
Share on other sites

Spoiler
On 1/22/2019 at 5:58 PM, McFlyever said:

Little Preview to my first fully recoverable Falcon 9.... I have to fix a few small bugs but the important thing - landing the Mainstage - is working really well right now!

 

 

 

 

First of all, that thing looks realy good but:
1. only block 1 had no octoweba t the bottom, block 4 was the first one to make a succesful landing
2. As BigBoy said, there is no fairing around the dragon capsule
3. the Dragon V2 trunk seems a bit too long fow what is should be
hoping for some more landing videos soon...
-HB Stratos

Edited by HB Stratos
Remember, always put quotes with Pics/Videos in a spoiler to keep the page clean
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...