GoSlash27

At higher velocities, pointing horizontally results in a negative θ WRT prograde. Since I want to achieve a desired apoapsis anyway, I just let it sling me up there and circularize on arrival. *edit* ^ what he said. Best, -Slashy

spinomonkey, If you have everything unlocked, the cheap way to go about it is a turbojet SSTO lifter. http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/Lifter-Ception This one can lift over 20 tonnes of payload into LKO for the cost of $1,000. Since it's fully recoverable, you won't lose any funds operating it (unless, of course, you crash it). If you want a copy of the craft file, just let me know. Best, -Slashy

^ Now having said that, I should point out that this is not a good way to design rockets. You should not be asking "how much can this stage lift" and building from the pad up, but the opposite. You should be building from the top down and asking "how much rocket do I need to lift this". Your designs will come out much more efficient that way, and you'll never have to ask this question because the most it can lift is exactly what you designed it to lift. Best, -Slashy

I definitely would not recommend relying on that form for launches, though. As Pecan pointed out, you need enough t/w or you're not going anywhere. However, there is a "sorta" cure: If you know your engine's Isp and thrust, then you can puzzle out the rest. Say you have a KR-2L engine (T=2.5MN and Isp=280). The most total mass it can lift at T/W=1 would be 2500/9.82= 255 tonnes. If we want to have this stage generate 1,000m/sec DV, than reversing the rocket equation (follow the link above) says: e^[1000/(9.82*280)] = Rwd 1.44; our rocket when fully fueled will weigh 1.44 times as much as it does dry. 255 tonnes/1.44= 177 tonnes. Our rocket will weigh 177 tonnes when dry and 255 tonnes when wet. So our fuel mass is 255-177= 78 tonnes. knowing that we are carrying 78 tonnes of fuel, we need enough tankage to hold it. Seeing as how this is a monster rocket, we'll need the Kerbodyne tank. It weighs 10 tonnes. So... 177 tonnes of dry mass. Subtract the weight of the tank= 167 tonnes. Subtract the weight of the engine= 161 tonnes. This is the absolute maximum mass you could lift 1,000 m/sec using a single KR-2L, assuming it is all nothing but payload. Anything additional that is not payload should be subtracted from this. You can change the numbers as necessary for your situation, but the math works the same. HTHs, -Slashy

I don't think they'll have a problem finding this one, so not the same thing at all. -CNNI wonder exactly what he means by "monitored the presence". If this means that the transponder was still functioning an hour and a half after it went down, this could be good news. -Slashy

I'll go with what Kryten said. Both would get you to space and back, but when the Mercury brought you back, you had control over where you ended up. Given the choice between being actively guided to recovery forces in a shelter or bailing out somewhere over Siberia, I'd rather go with the first option. Best, -Slashy

Neither do I. I suspect they *intended* the surface gravity to be 9.81 m/sec^2, but for whatever reason it ended up being 9.82 instead. Best, -Slashy

The first purple marker is anti-normal, the second is normal. The first blue marker is radial- out and the second blue marker is radial- in. Good morning! -Slashy

All true. The STS was originally designed to be a complete transportation infrastructure, not just a mostly- reusable launcher. When the funding for STS got axed, the launcher remained. Then reasoning that it would only fly 100 missions, they made a balance between initial cost and cost of operation and came up with a design that wasn't cheap to build *or* operate. That's how we ended up with the shuttle; a vehicle that was never really well- suited or economical for the jobs it wound up doing. Best, -Slashy

http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/Lifter-Ception/Flight noob Yeah, just messin' with ya... Best, -Slashy

This is a common instability mode. Usually it's the result of insufficient dihedral and empennage area. Try bending your outer wing panels up a bit and add more vertical winglets as far back as you can place them. See if that helps you. *edit* Also, those vertical canards out on the wingtips probably aren't doing you any favors. Best, -Slashy

Also for whatever reason the correct surface gravity for Kerbin is actually 9.82 m/sec^2. But mainly what arma said above: Your answer is only ever as accurate as the lowest resolution variable you put in it. You fed in your wet and dry mass to 2 digits, so your answer is only accurate to 2 digits. If you feed in both of these numbers to 3 digits, then your answer will only be accurate to 3 digits. I don't go any farther than that because I don't know if g on Kerbin is precisely 9.82 m/sec or not. Best, -Slashy

Locustgate, You really want your center of lift just barely behind your center of mass. You also want to make sure it stays that way throughout the flight, so fuel tanks need to be in the center of mass. Like this... Best, -Slashy

The last episode was over 20 years ago. I'm pretty sure there's at least a dozen kids googling "Scott Bakula" at this very moment. I used to like that show, too... /I feel so...old... -Slashy

Scott Bakula is not impressed -Slashy /dating myself

All, I figured I'd post this here before the next update comes along. This is a direct comparison of drag and mass for a fixed amount of lift for each wing surface type. KSP .90 Wing type comparison [TABLE=class: cms_table, width: 500] [TR] [TD]Type[/TD] [TD]Cl[/TD] [TD]Cd[/TD] [TD]Mass[/TD] [TD]N@Cl=10[/TD] [TD]Mtotal[/TD] [TD]Dtotal[/TD] [/TR] [TR] [TD]Swept[/TD] [TD]1.6[/TD] [TD].6[/TD] [TD].05[/TD] [TD]6.25[/TD] [TD].31[/TD] [TD].0641[/TD] [/TR] [TR] [TD]Conn A[/TD] [TD]2[/TD] [TD].5[/TD] [TD].1[/TD] [TD]5[/TD] [TD].5[/TD] [TD].0855[/TD] [/TR] [TR] [TD]Conn B[/TD] [TD]2[/TD] [TD].5[/TD] [TD].1[/TD] [TD]5[/TD] [TD].5[/TD] [TD].0855[/TD] [/TR] [TR] [TD]Conn C[/TD] [TD]1[/TD] [TD].25[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0428[/TD] [/TR] [TR] [TD]Conn D[/TD] [TD].5[/TD] [TD].12[/TD] [TD].025[/TD] [TD]20[/TD] [TD].5[/TD] [TD].0205 [/TD] [/TR] [TR] [TD]Conn E[/TD] [TD].5[/TD] [TD].12[/TD] [TD].025[/TD] [TD]20[/TD] [TD].5[/TD] [TD].0205[/TD] [/TR] [TR] [TD]Delta[/TD] [TD]2[/TD] [TD].6[/TD] [TD].1[/TD] [TD]5[/TD] [TD].5[/TD] [TD].1026[/TD] [/TR] [TR] [TD]Sml Delta[/TD] [TD].5[/TD] [TD].1[/TD] [TD].025[/TD] [TD]20[/TD] [TD].5[/TD] [TD].0171 [/TD] [/TR] [TR] [TD]Strake[/TD] [TD].75[/TD] [TD].2[/TD] [TD].025[/TD] [TD]13.3[/TD] [TD].33[/TD] [TD].0228[/TD] [/TR] [TR] [TD]Struct A[/TD] [TD]1[/TD] [TD].3[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0513[/TD] [/TR] [TR] [TD]Struct B[/TD] [TD]1[/TD] [TD].3[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0513[/TD] [/TR] [TR] [TD]Struct C[/TD] [TD].5[/TD] [TD].15[/TD] [TD].025[/TD] [TD]20[/TD] [TD].5[/TD] [TD].0257[/TD] [/TR] [TR] [TD]Struct D[/TD] [TD].25[/TD] [TD].08[/TD] [TD].012[/TD] [TD]40[/TD] [TD].48[/TD] [TD].0131[/TD] [/TR] [TR] [TD]Swept A[/TD] [TD]1[/TD] [TD].3[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0513[/TD] [/TR] [TR] [TD]Swept B[/TD] [TD]1[/TD] [TD].3[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0513 [/TD] [/TR] [/TABLE] So what I've done here is assumed the normal rule of thumb: 10x lift coefficient for each 10 tonnes of spaceplane. I've used enough of each wing type to achieve that goal. Then I assumed that they were in their most efficient angle of attack and looked at how much mass and drag they represented. The drag numbers are dimensionsless, and therefore do not take into account velocity or air pressure, but they are directly comparable to each other in any given circumstance. Now... for a 10 tonne spaceplane, a difference of a couple hundred kg doesn't matter much. But the drag is very important. As we climb over the 25-32km "hump", our engine thrust begins to reduce, and we are looking at our thrust to drag to keep us accelerating. Our 10 tonne spaceplane will generate 2 dimensionless "units" of drag in this regime, so it's vital that we don't add more drag than we have to. After that, it's just a matter of t/w to get us to orbit and circularized. I recommend that you use low drag and low mass wings whenever you can. I also recommend that you use the *proper amount* of wings whenever you can. Best, -Slashy

Gotcha and I'd like to table that discussion for the moment. I just wanted to verify that the numbers look good before I spread this table around. If it looks good from your house, I'm going to post it as a tutorial and then I'll explain in that thread why I disagree. Best, -Slashy

Like the others have said, the shuttle concept is not economically viable in KSP and didn't prove itself economical IRL either. Plain old layer cake rockets were always able to put payloads into orbit for less $ per kilo, which is why we're going back to them. SSTO spaceplanes, OTOH, are capable of putting payloads into orbit for ridiculously cheap. At least in KSP. Best, -Slashy

That balance is very bad. You never want your center of lift ahead of your center of mass. I can also see that you have nothing to keep your yaw (swiveling left and right) under control, so you'll want to see to that. Put some vertical tailplanes in the back so it'll want to point towards where it's flying. Best, -Slashy

Agreed. Also agreed. I prettied up arkie's table and made it more user- friendly. While I was at it, I removed the reference to DVR. Yeah, that's what I said. So I tried a launch from Eeloo to check it and (don't ask me why) I performed about 1% over what the model said I would. I'm guessing that sidereal rotation doesn't help you at the bottom end and doesn't save much at the top end. Beats me, -Slashy

And here's the craft file for my glitch- exploiter, *but*... http://wikisend.com/download/109270/k-2 testbed.craft If you don't still have the parts in your library file from KSP .24, you won't be able to use it. Best, -Slashy

Numerobis, If it's not too much trouble, could you look this over for any errors? I'm listing the wings by stats, assuming enough wings to work for 10 tonnes of spaceplane, and then calculating drag coefficients at 20* AoA. They are dimensionless, so V and p are not considered. Cl is assumed directly, while Dtotal is assumed as NM*sin20(Cd) KSP .90 Wing type comparison [TABLE=width: 500] [TR] [TD]Type[/TD] [TD]Cl[/TD] [TD]Cd[/TD] [TD]Mass[/TD] [TD]N@Cl=10[/TD] [TD]Mtotal[/TD] [TD]Dtotal[/TD] [/TR] [TR] [TD]Swept[/TD] [TD]1.6[/TD] [TD].6[/TD] [TD].05[/TD] [TD]6.25[/TD] [TD].31[/TD] [TD].0641[/TD] [/TR] [TR] [TD]Conn A[/TD] [TD]2[/TD] [TD].5[/TD] [TD].1[/TD] [TD]5[/TD] [TD].5[/TD] [TD].0855[/TD] [/TR] [TR] [TD]Conn B[/TD] [TD]2[/TD] [TD].5[/TD] [TD].1[/TD] [TD]5[/TD] [TD].5[/TD] [TD].0855[/TD] [/TR] [TR] [TD]Conn C[/TD] [TD]1[/TD] [TD].25[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0428[/TD] [/TR] [TR] [TD]Conn D[/TD] [TD].5[/TD] [TD].12[/TD] [TD].025[/TD] [TD]20[/TD] [TD].5[/TD] [TD].0205 [/TD] [/TR] [TR] [TD]Conn E[/TD] [TD].5[/TD] [TD].12[/TD] [TD].025[/TD] [TD]20[/TD] [TD].5[/TD] [TD].0205[/TD] [/TR] [TR] [TD]Delta[/TD] [TD]2[/TD] [TD].6[/TD] [TD].1[/TD] [TD]5[/TD] [TD].5[/TD] [TD].1026[/TD] [/TR] [TR] [TD]Sml Delta[/TD] [TD].5[/TD] [TD].1[/TD] [TD].025[/TD] [TD]20[/TD] [TD].5[/TD] [TD].0171 [/TD] [/TR] [TR] [TD]Strake[/TD] [TD].75[/TD] [TD].2[/TD] [TD].025[/TD] [TD]13.3[/TD] [TD].33[/TD] [TD].0228[/TD] [/TR] [TR] [TD]Struct A[/TD] [TD]1[/TD] [TD].3[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0513[/TD] [/TR] [TR] [TD]Struct B[/TD] [TD]1[/TD] [TD].3[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0513[/TD] [/TR] [TR] [TD]Struct C[/TD] [TD].5[/TD] [TD].15[/TD] [TD].025[/TD] [TD]20[/TD] [TD].5[/TD] [TD].0257[/TD] [/TR] [TR] [TD]Struct D[/TD] [TD].25[/TD] [TD].08[/TD] [TD].012[/TD] [TD]40[/TD] [TD].48[/TD] [TD].0131[/TD] [/TR] [TR] [TD]Swept A[/TD] [TD]1[/TD] [TD].3[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0513[/TD] [/TR] [TR] [TD]Swept B[/TD] [TD]1[/TD] [TD].3[/TD] [TD].05[/TD] [TD]10[/TD] [TD].5[/TD] [TD].0513[/TD] [/TR] [/TABLE] So what I've done here is gone by the old rule of thumb "1.0 lift coefficient of lift for each tonne of spaceplane". I've taken enough of each wing type to meet that, and then compared how much they weigh and how much drag they make. In the case of an SSTO spaceplane, we don't care much about a couple hundred kg in comparison to 10 tonnes of spacecraft. All we really need to worry about is drag. So in order (lower drag is better), these are the most efficient wings for the job in KSP .90 #1 Structural D. Absolute lowest drag, but unfortunately also highest part count. #2 Small Delta. Excellent drag, and also not too bad for part count. #3 Connector D&E. Excellent drag, but not quite as good as the small delta for the same part count. #4 Strake. Excellent drag, and part count is also very good. <-- My recommendation for most spaceplanes. #5 Connecter C. Good drag, very good part count. #6 Struc A,B, Swept A, and B. Average drag, good part count. #7 Swept wing. Excellent part count, fair drag. Anything below this, you really just plain should not use because they suck out loud. The worst of the worst is the delta wing. Use anything but that! Best, -Slashy

My apologies, I've side-tracked the original discussion with my little cheaty toy. It doesn't actually require any fuel whatsoever to do what it does. The monoprop is there JIC I want to dock in orbit. Deflecting the controls will accelerate it enough to get up to over 800 m/sec. Then you "release the kraken", which is a different physics exploit that gives you free continuous acceleration by attempting to force parts to disconnect. Back to the original subject, I'm ginning up a new wing comparison table for .90 KSP. I'll post a copy of it here when it's ready. Best, -Slashy

I ain't 'shamed! It's also egregious abuse of kraken drive.... 2Fer -Slashy

^ Take another look. That's Eve But yeah, it'll do Laythe and Duna as well. All in the same trip. Cheating is bad -Slashy