Help with Buran Style shuttle

[Jack5.exe]

1 minute ago, qzgy said:

Ohh, it might be an aero issue. Try adding fins to the bottom of your ET to make it a bit more lawndart-like and see if that helps.

K I'll add that in a bit i'm busy now

[sevenperforce]

19 minutes ago, Jack5.exe said:

K that worked, I actually got to booster separation that time... But I lost control, flipped around and reverted

How high was booster sep? You may need to lower SRB thrust to get a bit higher before separation.

Set the fuel priority drain order on the core to drain the lower tanks before the higher ones. This will push the CoM forward as the tanks drain, aiding passive aero stability and minimizing cosine losses.

And this probably goes w/o saying, but are you testing CoM/CoT alignment post-sep? By that, I mean pulling off the SRBs, draining about half the tank fuel, and ensuring good alignment, then getting launch thrust alignment fixed.

[Atkara]

I take it you're doing this as an exercise -otherwise, put it in a fairing and do a traditional launch. It's small enough.

[Jack5.exe]

13 minutes ago, Atkara said:

I take it you're doing this as an exercise -otherwise, put it in a fairing and do a traditional launch. It's small enough.

Putting a plane in a fairing as a lifter is like putting a small cargo bay in a big one, just stupid

25 minutes ago, sevenperforce said:

How high was booster sep

11,532

Edited January 21, 2018 by Jack5.exe

[Jack5.exe]

49 minutes ago, qzgy said:

Try adding fins to the bottom of your ET

Still failing

[Atkara]

19 minutes ago, Jack5.exe said:

Putting a plane in a fairing as a lifter is like putting a small cargo bay in a big one, just stupid

The United States Air Force, seems to think otherwise

[sevenperforce]

16 minutes ago, Jack5.exe said:

33 minutes ago, sevenperforce said:

How high was booster sep? You may need to lower SRB thrust to get a bit higher before separation.

11,532

Def lower the SRB thrust a touch, if you can. What's your takeoff TWR?

If you place Thuds separately, you can use an action group at staging to cut one and realign thrust.

[Jack5.exe]

Just now, Atkara said:

The United States Air Force, seems to think otherwise

People have opinions, stop trying to force me to use this

7 minutes ago, sevenperforce said:

What's your takeoff TWR?

2.55

[sevenperforce]

22 minutes ago, Jack5.exe said:

23 minutes ago, sevenperforce said:

Def lower the SRB thrust a touch, if you can. What's your takeoff TWR?

If you place Thuds separately, you can use an action group at staging to cut one and realign thrust.

2.55

Whoa! Yeah, definitely cut those SRBs way down. And you can absolutely afford lower thrust on the core, so replacing one Vector with a Thud or two is a really good idea.

[Atkara]

1 minute ago, Jack5.exe said:

People have opinions, stop trying to force me to use this

I expressed my opinion, you responded the way you did and I brought a real life example. I didn't try to "force you" to do anything.

Anyway, to launch a space shuttle like Buran did, you need to also take a look at the launch vehicle:

Energia didn't have 4 side boosters for fun and they weren't arranged like that for the looks. They were counteracting the torque, produced by having a shuttle on the launcher's back. Differential thrust, gimbals, even ballasts were used AFAIK. Buran's engines wouldn't fire at launch -they weren't powerful enough to make any difference but also, they didn't have to.

[Jack5.exe]

11 minutes ago, Atkara said:

I expressed my opinion, you responded the way you did and I brought a real life example. I didn't try to "force you" to do anything.

Anyway, to launch a space shuttle like Buran did, you need to also take a look at the launch vehicle:

Energia didn't have 4 side boosters for fun and they weren't arranged like that for the looks. They were counteracting the torque, produced by having a shuttle on the launcher's back. Differential thrust, gimbals, even ballasts were used AFAIK. Buran's engines wouldn't fire at launch -they weren't powerful enough to make any difference but also, they didn't have to.

I tried adding 2 SRBS earlier, flips at launch

Also i removed the vector, even with the SRB at 100% still wont launch, I'm keeping it

[Atkara]

5 minutes ago, Jack5.exe said:

I tried adding 2 SRBS earlier, flips at launch

Before putting the thing on the pad, you need to play around with their thrust limiters, in order for your Center of Thrust to match your Center of Mass. Post-launch, fuel is being consumed and as a result, the CoM moves. This means you also have to make in-flight adjustments on the thrust limiters. This is why SRBs won't cut it -you need to go LOX. 

In short, it's a management nightmare -at least for me. Yes, I tried a Buran-Energia-like design once and I did get it into orbit. Haven't used it eversince though, as I moved to SSTOs.

[sevenperforce]

15 minutes ago, Atkara said:

Before putting the thing on the pad, you need to play around with their thrust limiters, in order for your Center of Thrust to match your Center of Mass. Post-launch, fuel is being consumed and as a result, the CoM moves. This means you also have to make in-flight adjustments on the thrust limiters. This is why SRBs won't cut it -you need to go LOX. 

In short, it's a management nightmare -at least for me. Yes, I tried a Buran-Energia-like design once and I did get it into orbit. Haven't used it eversince though, as I moved to SSTOs.

I had never launched a true STS clone until a few weeks ago, but I had a lot of experience, so I got it on the first try:

Want to try a Buran clone soon.

48 minutes ago, Jack5.exe said:

I tried adding 2 SRBS earlier, flips at launch

Also i removed the vector, even with the SRB at 100% still wont launch, I'm keeping it

One Vector has the launch thrust of 8.7 Thuds. Something to keep in mind.

[invision]

its a balance issue so heres a dirty way to fix it. its still not perfect and starts to wobble a bit once out of the atmosphere but it makes it to space and will let you play with it.

okay the shuttle weighs almost 7 ton, so we take a fuel tank or 2 and we make it the same weight on the other side, right click the extra tank and turn off the fuel. we will use that fuel later.

i added a tail fin for flight stability, and 2 reaction wheels. (pic 3)

 

------------------------------------------------------------

since we are professionals we can just fly 45 degrees from the start

TALLY HO!

we can now turn the fuel to the tanks back on and shoot for orbit

main tanks drained and decoupled, shuttle on its own fuel. (mono)

now its time to land.

[Jack5.exe]

4 minutes ago, invision said:

its a balance issue so heres a dirty way to fix it. its still not perfect and starts to wobble a bit once out of the atmosphere but it makes it to space and will let you play with it.

okay the shuttle weighs almost 7 ton, so we take a fuel tank or 2 and we make it the same weight on the other side, right click the extra tank and turn off the fuel. we will use that fuel later.

i added a tail fin for flight stability, and 2 reaction wheels. (pic 3)

That vevolver replica is scarily acurate

[Rocket In My Pocket]

5 minutes ago, invision said:

since we are professionals we can just fly 45 degrees from the start

Do all the "pros" usually go the wrong way? Lol. Just kidding with ya. 

[Jack5.exe]

1 minute ago, Rocket In My Pocket said:

Do all the "pros" usually go the wrong way? Lol. Just kidding with ya. 

Polar orbit!

[Dman979]

Moved to Spacecraft Exchange.

[invision]

2 minutes ago, Rocket In My Pocket said:

Do all the "pros" usually go the wrong way? Lol. Just kidding with ya. 

yeah i know. lol was too lazy to spin the rocket

also dont forget a battery like i did and have to use the cheat menu 

[Rocket In My Pocket]

Just now, invision said:

yeah i know. lol was too lazy to spin the rocket

I made a habit of rotating the command pod first thing before I even start building the rest.

Messes me up if I do want a polar orbit though lol.

[Jack5.exe]

5 minutes ago, invision said:

yeah i know. lol was too lazy to spin the rocket

also dont forget a battery like i did and have to use the cheat menu 

Do I turn off the top tank too?

[invision]

Just now, Jack5.exe said:

Do I turn off the top tank too?

turn off only the tanks on the back added for balance, the main rocket remains untouched. 

once in space you can enable the use of them. use low thrust as balance is still awkward and you should be okay.

if you turn on the mono engines on the shuttle and go for orbit it seems to fix the stability issue and you can go full speed.

 

[Jack5.exe]

10 minutes ago, invision said:

turn off only the tanks on the back added for balance, the main rocket remains untouched. 

once in space you can enable the use of them. use low thrust as balance is still awkward and you should be okay.

Payload test seems good, mechjeb didn't circularize so I'm doing it again, it seems pretty good!

OK MECHJAB BE'N RETARDED DADDY JACK TAK'N OVR.... sorry lol

Got it into orbit! Thanks!

[invision]

okay i found the perfect balance.

just use 1 tank on the rear and this thing flew like a boss

 

 

months ago i was inspired by the XB shuttle and made a similar style setup. 

[sevenperforce]

On the subject of Buran -- does anyone wiser than I know what those rectangular structures on the outsides of the Zenit boosters were?