Shuttle Challenge v5 - The STS thread [Stock and Mod Friendly] - MAJOR CHALLENGE ANNOUNCEMENT! - 30.3.2020

[4x4cheesecake]

Well, I guess I'm done with the Mun challenges

Mun STS - 5 - 7

 

It's not my best design but at least, it is different
I screwed up a bit during STS - 6 (PPE) but ended with a pretty proud moment (shown in the clip below). There  is also a little, hidden 'issue', if you can find it, you'll get a cookie
Since uploading and describing screenshots is my least favourit part of a challenge (especially when it contains mutliple flights), I'll just post some highlights here. Any details can be found in the imgur album as usual

 

STS - 5 (Habitat Module + MMU)

Spoiler

Album: https://imgur.com/a/Jpm9JYu

 

STS - 6 (PPE + Pilot)

Spoiler

Tell me what's wrong in this picture and win a cookie

Album: https://imgur.com/a/QXOIEsG

 

STS - 7 (Lab + Crew)

Spoiler

Album: https://imgur.com/a/8wuH5K6
(I forgot to screenshot some maneuver setups...if they are required, I still have the record and can create as many screenshots as you want )

 

LOP-G (maneuver)

Spoiler

'Album': https://imgur.com/a/xi4V4Ep

 

My personal highlight during this mission:
While assembling the PPE, I've noticed that I forgot a second docking port I've decided to look for a more challenging way to dock parts together and ended with a pretty nice maneuver

 

[hoioh]

1 hour ago, 4x4cheesecake said:

I've decided to look for a more challenging way to dock parts together and ended with a pretty nice maneuver

Oh yeah! That is one sweet maneuver!

[michal.don]

Well, not going to spoil anything (just yet), but some of the guesses are... Interesting

13 hours ago, sturmhauke said:

Launching the shuttle from the back of an aircraft, while simultaneously launching its boosters from a submarine, and then docking them both together midflight and proceeding with the mission.

I like that idea, maybe for:

[sturmhauke]

BRB, gonna become a kOS expert real quick...

[michal.don]

23 hours ago, 4x4cheesecake said:

Well, I guess I'm done with the Mun challenges

Well, I guess you are

I like the uncommon design, and the fact it works pretty well - how much hassle was it to get the CoM just right? Also, the MMU is really cute  

For the cookie part - is it the SAS settings? Other that that, I can't see anything unusual....

I'm a bit surprised noone took the more difficult way of doing the transfers from and to Mun, meaning straight to polar orbit/straight to atmo and landing. But when the machines are so powerful and have so much fuel to spare, I guess there's no point in doing so. It might be just my RSS/rescale reflex to avoid burning any fuel whenever possible  

Good job commander, here's your badge:

And I guess we're heading to Duna pretty soon?  

Michal.don

[4x4cheesecake]

4 hours ago, michal.don said:

I like the uncommon design, and the fact it works pretty well - how much hassle was it to get the CoM just right? Also, the MMU is really cute  

Thanks

Actually, adjusting the CoM was easy but the DCoM is a mess...I had to remove some fuel from the conic shaped parts to balance the CoM but if someone actually need some of the remaining fuel, bad things will happen At least theoretically, a docked ship may needs a some fuel for some reason. There are no LFO consuming parts on board of the LOP-G so to 'justify' the LFO tanks, I have to assume they are used at some point...

4 hours ago, michal.don said:

For the cookie part - is it the SAS settings? Other that that, I can't see anything unusual....

Nope, the SAS is set to radial out to stabilize the first few meters of the flight but you are close If no one finds the solution, I'll solve the riddle along with my next mission report.

4 hours ago, michal.don said:

I'm a bit surprised noone took the more difficult way of doing the transfers from and to Mun, meaning straight to polar orbit/straight to atmo and landing. But when the machines are so powerful and have so much fuel to spare, I guess there's no point in doing so. It might be just my RSS/rescale reflex to avoid burning any fuel whenever possible  

Uhm...it is more efficent to perform a transfer into a equatorial Mun orbit and perform a second maneuver to set up a polar trajectory, isn't it? But yes, when I returned to Kerbin, I just took advantage from the powerful design

4 hours ago, michal.don said:

And I guess we're heading to Duna pretty soon?  

Almost on my way, just some more minor tweaks to the outpost design

Edited October 17, 2018 by 4x4cheesecake

[hoioh]

10 minutes ago, 4x4cheesecake said:

Nope, the SAS is set to radial out to stabilize the first few meters of the flight but you are close If no one finds the solution, I'll solve the riddle along with my next mission report

Only thing I could cone up with is the issue with RCS drift during your circularisation burn at the mün, but that was rather obvious I think

[4x4cheesecake]

1 minute ago, hoioh said:

Only thing I could cone up with is the issue with RCS drift during your circularisation burn at the mün, but that was rather obvious I think

That was an issue as well but there is one explicit in the picture which shows the launch and I fixed it until I had to separate the boosters

[hoioh]

1 hour ago, 4x4cheesecake said:

That was an issue as well but there is one explicit in the picture which shows the launch and I fixed it until I had to separate the boosters

On the small screen it may appear that you had a misfire on the right hand side booster for a bit, cuz it's still burning upon separation

Or it's just the totally wonked 2nd stage

Edited October 17, 2018 by hoioh

[4x4cheesecake]

43 minutes ago, hoioh said:

On the small screen it may appear that you had a misfire on the right hand side booster for a bit, cuz it's still burning upon separation

Nope, the boosters burned perfectly fine and were empty on separation.

43 minutes ago, hoioh said:

Or it's just the totally wonked 2nd stage 

It is 'wonked' because KER is a bit 'wonked' as well and this staging setup will provide correct dV readouts (Actually I'm curious why nobody noticed this one before )

I'll give you a little hint:

Spoiler

Don't look at the shuttle, it's the UI which will brighten your mind

 

edit: Duna STS - 1 is ready to go, just a few hours left to win a cookie^^

Spoiler

 

Edited October 17, 2018 by 4x4cheesecake

[hoioh]

2 hours ago, 4x4cheesecake said:

Don't look at the shuttle, it's the UI which will brighten your mind

Ah, I get it now:

Spoiler

1 thing has been clicked, but shouldn't have been at this stage of the flight. That one is only needed at the very end of the mission 

 

[4x4cheesecake]

5 hours ago, hoioh said:

Ah, I get it now:

  Reveal hidden contents

1 thing has been clicked, but shouldn't have been at this stage of the flight. That one is only needed at the very end of the mission 

 

You got it
Here is your cookie:

 

Meanwhile, I've finished the Duna STS - 1, so for everyone who still don't know what was wrong during the launch of my Mun STS - 6 mission: The landing gear was extended xD (You can see the illuminated button next to the altimeter)

Anyway, here is my next entry:

 

Duna STS - 1

I enjoyed this mission very much A simple but good looking design for the outpost and a wonderful flight while asking myself if the orbiter will survive the aerobreak at Duna and Kerbin when arriving from interplanetary space...this really kept up the thrill^^

Some highlights of the flight:
 

Spoiler

The outpost in the cargobay and without a shroud around the service module to show the (required) hidden probe core:

Launch at sunrise:

And transfer at sunset

Caught an eclipse while adjusting the trajectory:

Aerobreak at Duna:

Deploying the outpost and redock the cupola to the correct position:

Transfering the crew:

Let's get back home:

After a flyby of Ike, it's time to say goodbye:

Also a flyby of the Mun...

Not even close to the max. temp.:

I came in from a slightly inclined orbit, so I overshot the KSC to fly a curve:

Safe landing at the KSC:

Album: https://imgur.com/a/BIXWy6y
(Contains every maneuver and some really nice screens )

I also used this mission to test, if the shuttle will need some additional fuel for STS - 2 so I saved as much fuel as possible (that's why I didn't changed the inclination before landing at the KSC) and it looks like, I have to use a support package or put some extra fuel into the cargo bay when I try to land on Duna during STS - 2. Are they any restrictions regarding the support package I should know about?

[michal.don]

9 hours ago, 4x4cheesecake said:

Meanwhile, I've finished the Duna STS - 1, so for everyone who still don't know what was wrong during the launch of my Mun STS - 6 mission: The landing gear was extended xD (You can see the illuminated button next to the altimeter)

Anyway, here is my next entry:

That didn't take long  Aw, I missed the landing gear, no cookie for me.... Well, I might buy one during my lunch break, I kind of want the cookie quite much  

Glad you enjoyed the mission, and I'm glad to hear it was a different feeling taking the shuttle interplanetary, I felt the same in my first Duna run. Everything fine with the execution, too, no questions on my part this time  

About the "support package" - pretty much no restrictions. Could be anything from a fuel depot to a second shuttle.

Alright, here's your badge, good luck with the landing!

Michal.don

[sturmhauke]

STS-2b fuel pod recovery is complete!

full album: https://imgur.com/a/S4vqQwR

Spoiler

 

[hoioh]

11 hours ago, 4x4cheesecake said:

Here is your cookie

YAY! 

[Kerbolitto]

16 hours ago, 4x4cheesecake said:

Duna STS - 1

I enjoyed this mission very much A simple but good looking design for the outpost and a wonderful flight while asking myself if the orbiter will survive the aerobreak at Duna and Kerbin when arriving from interplanetary space...this really kept up the thrill^^

Some highlights of the flight:
 

  Reveal hidden contents

The outpost in the cargobay and without a shroud around the service module to show the (required) hidden probe core:

Launch at sunrise:

And transfer at sunset

Caught an eclipse while adjusting the trajectory:

Aerobreak at Duna:

Deploying the outpost and redock the cupola to the correct position:

Transfering the crew:

Let's get back home:

After a flyby of Ike, it's time to say goodbye:

Also a flyby of the Mun...

Not even close to the max. temp.:

I came in from a slightly inclined orbit, so I overshot the KSC to fly a curve:

Safe landing at the KSC:

Album: https://imgur.com/a/BIXWy6y
(Contains every maneuver and some really nice screens )

I also used this mission to test, if the shuttle will need some additional fuel for STS - 2 so I saved as much fuel as possible (that's why I didn't changed the inclination before landing at the KSC) and it looks like, I have to use a support package or put some extra fuel into the cargo bay when I try to land on Duna during STS - 2. Are they any restrictions regarding the support package I should know about?

 

Very nice mission ! It seems that your shuttle has a high TWR ? (I'm used to >0.5 on my ships, and even that is HUge xD) Also did you tried to incline it (left-right) during Kerbin's re-entry to correct the descent on KSC ? It works quite well when you're going below 1800m/s  +/-

[4x4cheesecake]

21 minutes ago, Kerbolitto said:

 

Very nice mission ! It seems that your shuttle has a high TWR ? (I'm used to >0.5 on my ships, and even that is HUge xD) Also did you tried to incline it (left-right) during Kerbin's re-entry to correct the descent on KSC ? It works quite well when you're going below 1800m/s  +/-

Thank you

The KER window left to the altimeter displays the TWR: right after launch I got a TWR of 0.36, in low Duna orbit it's 2.17 (still carrying the payload) and 2.45 after deploying the outpost, back in LKO it's 0.89. Compared to the values you are used to, it's pretty high I guess

I've tried some corrections during aerobreaking on my last Mun mission but not during the landing descent. Usually, I have to prevent any maneuvers between ~30km and ~10km altiutude because I'll lose control of the orbiter (it will start to spin and the wings may rip apart). Probably a bad combination of huge wings/lift and CoL/CoM beeing close together. Since I can work aorund the issue by relying on the high gliding capabilities at low speed, I never tried to actually fix it xD 

If you are not familiar with RCSBuildAid: The red dot displays the dry CoM.

 

[Kerbolitto]

25 minutes ago, 4x4cheesecake said:

The KER window left to the altimeter displays the TWR: right after launch I got a TWR of 0.36, in low Duna orbit it's 2.17 (still carrying the payload) and 2.45 after deploying the outpost, back in LKO it's 0.89. Compared to the values you are used to, it's pretty high I guess

Yeah that's very high indeed :p I focused on dV before everything else and 2 nukes for 120t. max capacity is quite bad ...

 

26 minutes ago, 4x4cheesecake said:

I've tried some corrections during aerobreaking on my last Mun mission but not during the landing descent.

Did you tried to change inclination using the Mun ? Sometimes it helps !

 

27 minutes ago, 4x4cheesecake said:

Usually, I have to prevent any maneuvers between ~30km and ~10km altiutude because I'll lose control of the orbiter (it will start to spin and the wings may rip apart). Probably a bad combination of huge wings/lift and CoL/CoM beeing close together. Since I can work aorund the issue by relying on the high gliding capabilities at low speed, I never tried to actually fix it xD 

If you are not familiar with RCSBuildAid: The red dot displays the dry CoM.

Maybe your CoM CoL are too close, just a small deviation creates tons of drag with a wingspan this big. Did you moved fuel forward during descent ? Between 30-20k is the best spot to change course because of high speed and thick atmosphere, and it's free ! :p

[4x4cheesecake]

18 minutes ago, Kerbolitto said:

Did you tried to change inclination using the Mun ? Sometimes it helps !

The last time I used the mun was during the STS - 9 mission, so I know about it and how to do it but I didn't care about my inclination this time

22 minutes ago, Kerbolitto said:

Maybe your CoM CoL are too close, just a small deviation creates tons of drag with a wingspan this big. Did you moved fuel forward during descent ? Between 30-20k is the best spot to change course because of high speed and thick atmosphere, and it's free ! :p

Well, it's a walk on the edge. Having CoL and CoM close together also means, that you don't need much pitch authority to control your AoA but you're at the risk of spinning. Since my control surfaces are pretty small comapred to the lifting surfaces, I'll almost loose pitch authority completely as soon as I shift the CoM forward. RCS can helps a bit to comensate but usually I'll just crash into the ground. Maybe, there is something like a 'sweet spot' for the CoM but at some point I just want to spent time in the air/space and not in the editor so I'll just deal with it^^

By the way: I just reloaded a savegame from Duna STS - 1 and tried to land the orbiter on the surface while having a reasonable amount of fuel left. Last time I've tried it, I used a full fueled orbiter and crash during every attempt (because of missing pitch authority). This time, while using a much lighter orbiter, I had absolut no problems and did it on my first try. Duna STS - 2 will be a walk in the park

[Kerbolitto]

44 minutes ago, 4x4cheesecake said:

Well, it's a walk on the edge. Having CoL and CoM close together also means, that you don't need much pitch authority to control your AoA but you're at the risk of spinning. Since my control surfaces are pretty small comapred to the lifting surfaces, I'll almost loose pitch authority completely as soon as I shift the CoM forward. RCS can helps a bit to comensate but usually I'll just crash into the ground. Maybe, there is something like a 'sweet spot' for the CoM but at some point I just want to spent time in the air/space and not in the editor so I'll just deal with it^^

Personnaly I choosed to put dual canards because the shuttle is stubby and very heavy, even when empty. At first I wanted to avoid that but to keep a clean look but it worked so well that I enjoy a lot more flying this as a plane now . It certainly helped on many re-entries to loose speed, or on Laythe when deorbiting the ground station !

[4x4cheesecake]

20 minutes ago, Kerbolitto said:

Personnaly I choosed to put dual canards because the shuttle is stubby and very heavy, even when empty. At first I wanted to avoid that but to keep a clean look but it worked so well that I enjoy a lot more flying this as a plane now . It certainly helped on many re-entries to loose speed, or on Laythe when deorbiting the ground station !

That's how I do it on many SSTOs as well Two canards at the front and and you can fly almost every maneuver with ease^^
But like you said: I also want to keep the clean look on my orbiter

I got curious anyway and did a quick test. This is the difference I've created in distance between CoL and CoM (by shifting fuel while keeping the same mass):

While CoL and CoM are close together, I was able to launch from the runway, fly around the KSC and land with a speed of 60m/s at the runway.
After shifting the CoM forward, I was still able to launch from the runway, fly around the KSC (but I had to fly a bigger curve) and that's it...I was no longer able to pitch up at a speed of 100m/s and I just crashed into the ground with the nose pointing down in a 30° angle.

I'll definitly keep my configuration, it's not worth to fiddle around with tiny differences in distances between CoL and CoM when I'm actually able to land at the KSC already (usually at the first try)

[Kerbolitto]

24 minutes ago, 4x4cheesecake said:

While CoL and CoM are close together, I was able to launch from the runway, fly around the KSC and land with a speed of 60m/s at the runway.

After shifting the CoM forward, I was still able to launch from the runway, fly around the KSC (but I had to fly a bigger curve) and that's it...I was no longer able to pitch up at a speed of 100m/s and I just crashed into the ground with the nose pointing down in a 30° angle.

I'll definitly keep my configuration, it's not worth to fiddle around with tiny differences in distances between CoL and CoM when I'm actually able to land at the KSC already (usually at the first try)

If you land at first try its fine then ! Also I did not meant transfer all the fuel, but by adding a little in the front or back while pitching, you can get a good feeling at how stable the shuttle is. Landing at 60m.s is quite good

[sturmhauke]

My suggestions:

Don't move the CoM too far forward. Difficulty pitching up is expected in that case; you've increased stability, but that just means that you'll have a nice, stable trajectory into the ground.

Add more vertical stabilizer surface. You can use two or more shuttle fins, or build one out of wing parts and elevons. Flat spins are a sign of yaw instability, especially if your CoM is already foward of the CoL.

Reduce your wing area and add some flaps. This will reduce overall drag while still giving you good low-speed performance. Airplane Plus has some good ones, or you can make your own. Set some of the elevons you already have so they don't respond to control input. Instead, set them to deploy downwards on an action group. On a delta wing, this does tend to add a lot of down pitch though, so be careful. You can also add flaps on the leading edge, or even midwing if you don't mind it looking weird.

[4x4cheesecake]

31 minutes ago, Kerbolitto said:

If you land at first try its fine then ! Also I did not meant transfer all the fuel, but by adding a little in the front or back while pitching, you can get a good feeling at how stable the shuttle is. Landing at 60m.s is quite good

I shifted half the fuel from a 'MK3 Rocket Fuel Fuselage Short' from the back to the front. That's 562.5 units of LF and 687.5 units of OX...that's not 'all the fuel' just a bit (~7.5% of the fuel mass since the orbiter was just half fueled).
Anyway, I get your point and I'll come back to it as soon as it is necessary (i.e. if I cannot change my inclination with other methods)

@sturmhauke Thanks for your suggestions

I may should clarify two things:
1) When I designed my orbiter, I had a few things in mind that I want to achiev and I spend weeks on the design so it looks in a way I like and I can do the things I want to do (i.e. land on the mun and return to kerbin, very high glide capabilities, easy adjustable OMS to account different payload desings...)
2) I'm actually not looking for a fix since I can handle my orbiter pretty well Well, if someone can think about a possible improvment which can be done without changes on the design and it can be done easily, I'm inclined to try it.

Nevertheless, I like to discuss about it. I keep those things in mind whenever I have to build something new and other people may learn something as well

40 minutes ago, sturmhauke said:

Flat spins are a sign of yaw instability, especially if your CoM is already foward of the CoL.

I actually never analysed the type of spinning and thought about possible reasons for different types... I'll keep that in mind

[michal.don]

23 hours ago, sturmhauke said:

STS-2b fuel pod recovery is complete!

Looking very good!. And the fuel pod looks so small in the enormous cargo bay, I can already see the wild stations and bases that will be able to fit in this one  

Good job, here's your badge:

 

EDIT: @4x4cheesecake, your spin looks like a textbook example of yaw instability, indeed. Consider this, your vertical stabilizer is meant for spaceshuttle-sized-spaceshuttles (no matter how weird ths expression sounds, you know what I mean  ), and it barely does the trick. I know you are fond of your design, but I thinks that a slight redesign in this department (airbrakes maybe? wingtips?) would do wonders for your spacecraft.

 

also - my take on the CoM/CoL matter - My shuttles are always in the "high stability/low maneuverability/lots of pitch authority" camp. Why? I like to be able to steer the thing quite significantly, even in high atmosphere. You need a lot of stability, and even rolling a bit to the side and maintaining AoA of about 7-10 degrees can do wonders for your trajectory, and impact the landing place by hundreds! of kilometres. When I was used to my shuttle, I did not bother with changing inclinations or orbital heights before reentry, I just reentered on the right side of Kerbin, and glided home 9 out of 10 times, even from wildly eliptical and highly inclined orbits.

(And to be honest, I am sometimes a bit disappointed when even the best pilots of you always go to the perfect 100x100 equatorial orbit before reentering instead of just going for it, that's not the right stuff  )

Michal.don

 

Edited October 19, 2018 by michal.don