GoSlash27

Actually, DDE, this is false. Closing intakes is *supposed* to reduce drag, but it doesn't in the current implementation. Best, -Slashy

I think #3 is the big problem; less thrust does not mean less fuel consumed. It just means more total DV required for the trip due to drag losses. Good luck, though! -Slashy *edit* Perhaps you could use a very low t/w and low wing loading to "sail" your way to orbit using LV-Ns? Just hang out at the highest altitude where you can maintain level flight and slowly build speed until you eventually circularize? The heat might prove to be too much, but this might be the only way to SSTO from Eve. Best, -Slashy

#1 judging your efficiency purely by DV numbers is misleading. That says nothing about what kind of launcher you will have to build, how much fuel it will expend, or what it will cost. #2 burning to LKO and then transferring to an intercept is mathematically more efficient, even when judging purely by DV numbers. Best, -Slashy

Commish, I'd recommend moving the rudder further back and adding elevators/ canards (whichever trips your trigger). Best, -Slashy

I don't normally do large launchers, but I was bored and looking for something different to do. This is what I came up with: The Monstro 1.0. 318 tonnes of payload to LKO, 1.42 thousand tonnes on the pad. What's the biggest beast you've ever launched? Share your pics and video here! Best, -Slashy

Assuming a ballistic transfer from 70km to 11.4 Mm and back, the round trip takes 2d, 2h, 48m, 31.3s. Anything you do prior to the transfer and while in the Mun's SoI adds to that time. Best, -Slashy

This is why I scratch my head when people make interplanetary space planes; sure you can do it... but why would you want to? Longer R&D time for something that's only going to get used once, more risk, and it's carrying a lot of stuff that's not needed for the trip. To each his own and all... but perhaps a ship destined for Bop is a bad comparison. Space planes do a good job at shuttling crew and supplies between KSC and LKO. When used in this role, the measure for efficiency is how cheaply it operates. Best, -Slashy

I concur with what Snark said. Adding to this, you can do with less intake area and more static incidence. Also, those airliner wings are prone to overheating on reentry. I recommend the shuttle wings instead. Best, -Slashy

Shaun, I define "efficiency" in space planes as operational cost per tonne of payload to orbit. There's not enough info provided here to evaluate that, so the next criteria is payload fraction. It looks looks decent. Not great, but decent. 22% is respectable for a Mk. 2 design. IIRC, I hit 28% in that range. Looking past pure efficiency, there's also the matter of utility and reliability. IMO that's even more important than efficiency. A good SSTO is easy to operate and completes the mission safely every time. You'd be in the best position to evaluate that. Best, -Slashy

First stage: 1,800 m/sec calculated at 1/2 atm and minimum 1.2 t/w at 1 atm. Second stage: 1,700 m/sec vac and minimum 0.7 t/w vac. This puts the staging right about 27 km altitude and 800 m/sec, allowing staging with no fear of tumbling. As a result, all the aero stuff and shells can be jettisoned with the first stage. Best, -Slashy

New career. Preparing to strip- mine the Mun for science.

#1 I don't believe parts suck up nearly enough memory to be the problem people make them out to be. #2 I would love to have a whole slew of parts and adapters for the .625 and 1.875 ranges. The big gripe is that we have to wade through so many parts that we never use... but that's why we have part filtering. I'd rather throw away parts I don't want than tell somebody else that they can't have them. Best, -Slashy

^ This. If you do the Duna intercept burn in low kerbin orbit, the map is correct. Best, -Slashy

The payload would be the fuel itself, had I finished out the design. It's just an example. Best, -Slashy

BR00NER, LN400 outlined the process for figuring t/w above. I don't bother limiting my throttle on upper stages (I consider 0.7 the minimum for this job), but I do limit it on boosters so that it wants to follow an efficient gravity turn. When I say too steep on the boost stage, I mean the tilt... although that can also result from too much thrust. Basically a boost stage that is too steep will leave your transstage too high and slow. You don't have enough time to circularize before you're past apoapsis and falling back down. HTHs, -Slashy

True, but these examples aren't intended for that. They just show what can be accomplished by minimizing drag instead of adding engines. Spaceplanes are very tolerant of extra wing area. Just reduce the incidence and the only penalty is weight. Best, -Slashy

Sadly, no. Not since the aero change. There are only a few engines that work at sea level on Eve, and none of them are capable of producing 8 km/ sec dv. Best, -Slashy

Another extreme example: 268 tonnes of spaceplane can still get hypersonic, even with just 8 RAPIERs. Best, -Slashy Actually, the responsiveness is just about right for a spaceplane. I don't recommend a lot of agility for spaceplanes. They should sled their way out of the atmosphere with minimal deviation to minimize drag. I knocked this one together as a quick example, so it's not optimized. Best, -Slashy

^ While Mk2 bodies do produce lift, I don't recommend taking advantage of it. They are very inefficient and create a lot more drag than the equivalent wing surface would. SSTO space planes are all about controlling drag. The most important piece of wisdom I can impart is this: Rotate your wings a few degrees so that they produce enough lift to keep your prograde vector aligned with your nose at Mach 1. Your fuselage is very draggy when it's not perfectly aligned with the airflow. This allows you to use less engine mass to get out of the atmosphere, which means more payload in orbit and less cross section drag. Also, I recommend the Big S delta wing for space planes. They're basically "free" fuel tankage from a drag perspective. Also more rigid than cobbling together panels, which will allow you to get rid of those draggy struts (struts are the devil). Best, -Slashy Here's an example of a very simple Mk. 3 space plane to illustrate: This one weighs 126 tonnes at launch, yet requires only 4 RAPIERs to achieve orbit with 31t of payload. You can see where I've rotated the wings for static incidence and paid careful attention to form drag. Best, -Slashy

I design my upper stage to have .7 t/w. An ideal second stage burn should keep your apoapsis about 45 seconds ahead. If you can't keep Ap ahead of you that far, you're probably short on thrust. It could also be that your first stage was too steep or lacking DV. Best, -Slashy

It depends on what you're doing. The LV-909 is superior for orbital insertion from Kerbin and interplanetary travel under 2 km/sec DV (which is a surprising amount of travel). The LV-N is superior for lower thrust applications and interplanetary travel above 2 km/sec *but* is still disproportionately expensive. Best, -Slashy

My greatest achievement would probably be achieving orbit purely on ions without using control surfaces back in .25. The most difficult thing I've ever done in KSP. Best, -Slashy

Here's an example of a very simple Mk.3 spaceplane for 1.1.3. 30 tonnes of payload to LKO with plenty of fuel reserve for the trip home. About 26% payload fraction, 1 engine per 32t of spaceplane, 1 wing , precooler intake, and Mk2 fuel tank per engine. This is a bit close to the "underpowered" end of the spectrum. Best, -Slashy D'oh! Sorry... *sheepish grin*

You're quite welcome. That's a pretty old design now. Spaceplanes don't require as much intake area as they used to. The Mk.3's low form drag-to-mass also means that you can get by with a lot less engine as well. I haven't posted any 1.1.3 Mk.3 designs yet. I think I oughtta. Best, -Slashy

^ Good point. There should be an option in the poll for "I don't use either". Best, -Slashy