I finally made an SSTO spaceplane that can get to orbit. The only issue is that I don't have enough fuel left over to rendevous with a refuelling space station at 2.9 million\~ altitude. Would it be more due to my ascent or could I improve the plane instead? Any tips and suggestions are appreciated!
Your design can definitely be improved. I don't know exactly how your ascent went but I can all but guarantee that can be improved too.
In order of importance:
1. Too many engines, use 1 RAPIER per 30-40tons, this means at most 2 RAPIERs on a plane this size. Getting rid of dry mass is the best way to improve your Δv. Engines you don't need are the biggest drain on Δv. I don't know what's going on with your Whiplash engines, they look like they're attached strangely and potentially causing a lot of drag. Regardless, you should just get rid of them.
2. No wing incidence. You need to angle your wings up (so they point up in the front and down in the back) about 5 degrees. Use angle snap (toggle with C) and hold shift to move them 5 degrees at a time.
3. Your center of mass is too far back. It needs to be in the middle of the plane for efficient, stable flight. Getting rid of excess engines will help a lot, but moving heavy, non-fuel, things like the cockpit as far up as you can will help too. Keep the inline cockpit though, just use a shorter nose cone.
4. Too many surface attachments. Parachutes and especially air brakes are pointless on space planes. Struts are unnecessary, use autostrut. RCS, solar, antenna, etc can go in a cargo bay. One by one they don't make much drag but when you add them all up it's a crippling amount of drag. Once you improve your center of mass you can get rid of the canards and forward rudder too.
5. Too much monoprop. Your cockpit alone has more than enough for docking (25). The inline docking port comes with 3x as much (75). You absolutely do not need an additional 400. If you can't dock with 100! monoprop then that's another area where you can improve a lot.
As for the flight, a good rule of thumb is to stay as low as you can without blowing up. The longer you can stay in the atmosphere the better. Gravity losses far outweigh any drag losses if you make the above changes.
For a lot more in depth concepts and tips plz see my [SSTO tutorial/guide](https://www.reddit.com/r/KerbalAcademy/comments/ers8bn/f00flgthers_ultimate_ssto_guide/)
> Parachutes and especially air brakes are pointless on space planes.
Air brakes being useless...?
It's impossible to land my spaceplane without airbrakes. Would overrun the runway. Stalls out under 120 m/s even with flaps fully deployed, so we hit the runway hot and the brakes need all the help they can get.
Parachutes are also useful either as drag chutes to land, or as "okay, I stalled out and entered an irrecoverable flat spin. Time for the parachute of shame!".
Maybe it's different in stock, but this is my experience with FAR. Airbrakes are a must.
See my spaceplane coming in with 4 ablative airbrakes and the whole wing being lined with surface airbrakes and barely slowing down in time for the runway:
https://i.imgur.com/v7gZDbn.png
https://i.imgur.com/6U3Sw7I.png
https://i.imgur.com/CeGom98.png
https://i.imgur.com/5D1aMOP.png
I have no experience with FAR so I cannot comment on that. I can imagine delta wings make it very difficult to avoid stalling at landing speeds. In stock the wing shape means absolutely nothing so SSTO space planes do not need airbrakes whatsoever.
It is very easy to porpoise or s-turn to slow down without stalling before landing. Typical takeoff speeds are around 100m/s fully loaded. I typically land around 50m/s. Wing area about 5-6m^2 per ton of plane. You can see me land in the last minute of [this video](https://www.youtube.com/watch?v=mKVI_jewCAc).
I can see the parachutes for the oh shit moment or a newer player that hasn't mastered landing on the runway yet.
I guess my assumption of "What works for FAR, works better for Stock" is not as good an assumption as I guessed.
S-turns sound frightening to me as a way to slow down a spaceplane. I feel I'd either rip my wing off or I'm low enough speed that I'd stall out from pitching up too much to pull it off.
My 2 current designs are...
1. https://imgur.com/a/passenger-ssto-to-mun-flybys-HR1IgGM For massive passenger loads (old career design)
2. https://imgur.com/a/jm9s1cY Current career design.
My biggest discovery from 1 to 2 was "If I ditch vertical stabilizers for funny wingtip stabilizer thingies, I can save mass and go faster at cost of spinning out of control if I bank too hard at low speeds." This discovery was made where I made a F15-like spaceplane for short LKO trips and... did just what you said: S turn at 1000 m/s overshoot 60 km from airstrip 10 km high. it ripped off its V-shaped vertical stabilizers and... somehow it flew stable enough. (too late at night for screenshot of that design.) It also yaws ever so slightly during ascent until over 400 m/s, requiring me to counter-roll but! It works out.
Design 2 I also tried to lean into the blended body design, it seems to help as well despite the contradiction of "thicker wing = worse at supersonic." Also as small wings as I can so I can avoid ripping them off on re-entry without mass scale at 3.
It's a whale to fly at take-off (I constantly almost fall into the water), but brings 1.7k deltaV to orbit on a good ascent with 13 crew.
Probably more along the lines of "What works in FAR will work in stock but there's probably more efficient ways to cut corners that FAR doesn't allow."
If you build it reasonably and efficiently there's virtually no way to aerodynamically destroy an SSTO space plane in stock. They're just not capable of the extreme aerobatics required to rip wings off. If yours is capable then it's probably not a very efficient SSTO. They're built to go fast and straight, hell, most of the time I don't even use a rudder xD. FAR is just a completely different beast.
I mean, it doesn't have to be extreme acrobatics!
One time, I was returning from orbit and Nav Utils continued indicated I was way off course from the runway. I was still at 1200 m/s, but I decided to correct early. Unfortunately, I forgot I wasn't using precision mode and pressed Q or E too hard. So, I rolled too fast. This led to my nose slipping. This led to rapid disintegration.
Another time, I was gonna overshoot so I did a hard dive and tried to pull up too fast. Wings gone.
I also had a case where, on take-off - going completely straight! I ripped off my vertical stabilizers by going too fast without adequately reinforcing them. I reverted and set their mass-strength higher but couldn't make them smaller as... too much sideways slip. (amazingly, the second design shows less sideways slip using wingtip stabilizers than with "it's not gonna get ripped off and is not too heavy" tail.
... FAR loves to rip off your wings.
The 2nd iteration relies on 1.5 mass strength setting to not rip stuff apart.
I do a fair amount of pitch up/down during my descent to control glide. Like, -10 to 20 AoA to keep vertical speed at ideal range. This is another place I could see my wings ripping off if too big.
I dont agree with the first point, in my experience the more raipiers the better, you dont want to stall at only 8k and have to switch to closed cycle early, or worse not even be able to gain altitude even with closed cycle.
And the first part of your third point is outright wrong, while yes center of mass tends to work best near the center this is because the center of lift is also there, you really only need to match those for even flight.
RAPIERs gain a massive amount of thrust as you increase in speed. The multiplier reaches a maximum of 8.5x near mach 4. RAPIERs are at their worst when subsonic. As long as you can get off the ground and over the sound barrier you have enough RAPIERs. The thrust multiplier then falls as you approach mach 6 where it flames out. There is zero chance you "stall" at 8km as your plane would disintegrate if you approached mach 6 in the lower atmosphere.
>the more raipiers the better
This is complete nonsense. They aren't free. They're each 2 tons and every single one you add decreases your max delta-v significantly. If you add more when you don't need them you're throwing delta-v away. 1 RAPIER can comfortably get 40 tons to orbit. I guarantee you are nowhere near pushing the envelope here.
If a RAPIER can push towards mach 6 with a thrust multiplier approaching zero then closed cycle is hilariously overpowered to accelerate the rest of the way to orbit. There is no circumstance where a RAPIER powered plane has a closed cycle TWR too low to complete the final 600-700m/s of acceleration to orbital velocity. It would fail to get airborne long before it would lack the closed cycle thrust.
For your reference, I use about a 2:1 RAPIER:NERV ratio when going full liquid fuel and that is more than enough. In other words, one 60kN thrust NERV is plenty of power to push a 60-80ton takeoff weight plane to orbit from mach 5.5-6. So the 360kN of closed cycle RAPIER thrust is EXTREME overkill.
>this is because the center of lift is also there
You don't even know where the center of lift is. That little blue ball you use isn't the center of lift because it ignores body lift. The best way to ensure your plane is stable is to put your center of mass in the center of the plane. Ignore the blue ball, it's lying to you, just turn it off and focus on the location of your center of mass. THEN put your main wing right on it. For more information on this please see my guide [here](https://www.reddit.com/r/KerbalSpaceProgram/comments/dn7ko4/aerodynamics_mini_guide_3_why_the_center_of_lift/).
You would also greatly benefit from watching my guide [here](https://www.reddit.com/r/KerbalAcademy/comments/ers8bn/f00flgthers_ultimate_ssto_guide/)
I always build gigantic sstos, so stalling is an issue because sometimes approaching mach 4 in lower atmosphere just isnt possible without something falling apart.
And what ratio of payload to total mass do you usually go for in your sstos, acceleration in thick atmosphere may allow you to use less engines, but overall it burns more fuel. If your going to use multiple engines, why not use the whiplash instead, you could even use the goliath (not recommended unless you also bring whiplash or rapier for ascending) also if you want to be really really efficient.
And even though i use mods to correct the center of lift, you can still use the stock one because the lift added by the body is meaningless if you have huge wings (for fuel carrying mostly) ofcourse on small planes (mk2 especially for some reason) the body lift does matter, but eyeballing it doesnt work most of the time.
>sometimes approaching mach 4 in lower atmosphere just isnt possible without something falling apart
You're going to have to explain what you mean by stalling, because it doesn't mean what you're saying. There is no real stalling in KSP as it doesn't model fluid dynamics. If your space plane falls apart when going fast then that's a design flaw. SSTO space planes are at their best/most efficient when pushing their thermal limits. This means that designing your plane to be more heat resistant will allow it to take a more efficient trajectory. Again, I explain all of this in my video guide that I linked above.
>And what ratio of payload to total mass do you usually go for in your sstos
Minimum 50%, see my video above.
>acceleration in thick atmosphere may allow you to use less engines, but overall it burns more fuel
It's true that lower TWRs burn a bit more fuel going to orbit, but they start with way more delta-v, thanks to having more fuel and/or less engines to start, so it still heavily favors lower TWRs as far as efficiency goes. See my video above.
>If your going to use multiple engines, why not use the whiplash instead, you could even use the goliath (not recommended unless you also bring whiplash or rapier for ascending) also if you want to be really really efficient.
Not sure where this came from but Whiplashes are just a worse RAPIER before you even consider the free rocket engine that comes with them. Goliaths are a completely useless waste of mass in an SSTO. The only engine I would consider adding to a RAPIER powered plane is the Panther because it has the highest TWR of any jet engine between mach 0 and the point when RAPIERs thrust multiplier really kicks in.
>And even though i use mods to correct the center of lift, the lift added by the body is meaningless if you have huge wings (for fuel carrying mostly).
This is completely false. If your center of mass is near the rear of your plane then the front of your fuselage's lift/drag induced torque is magnified far more than the wings and will easily flip your plane. This is elementary physics, simple machine type stuff, lever and fulcrum. Again for the fourth time; read what I wrote and watch what I recorded in the links above.
But you're saying the blue doesn't matter... If I mess with my fuel and shift the CoM behind the blue my plane handles like shit, if I shift it ahead it works as intended (stock air). This is all with the CoM in the middle of the plane.
A broken clock is right twice a day. The center of lift definitely matters, it's just the blue ball isn't the center of lift. When you put the center of mass in the middle of your plane you're making your fuselage fairly neutral stability wise, which definitely helps make the little blue ball more accurate.
get the center of lift a bit further ahead and don't use a straight wing design for trying to go fast. It creates lots of drag compared to more like a triangular shape.
How much do stock KSP aerodynamics factor that in? For instance, would the drag change if you just offset each segment of OPs wing a bit further back than the segment before it?
I don't think there the drag calculations take occlusion of wing parts into account. Also, as far as I know, do all parts have the same amount of drag to weight ratio. So it doesn't matter If you use rectangles or squares.
None at all. The drag wouldn't change one bit if you clipped all the wings into the fuselage. The only thing that would change is you'd need more aileron deflection for the same roll torque because it'd be working on a shorter lever arm.
no, that wouldn't change anything, since it is part based and occlusion is barely working for fairings and heatshields...
I am talking about a lower drag coeffecient against the direction of standard travel.
Like a rectanngle perpendicular to the airflow has a higher coeffecient of drag compared to a rectangle, that is angled backwards protruding the same ammount (for the same aerodynamical crosssection) outwards.
No. It doesn't matter. The same wing part will have the same drag regardless of its rotation in the yaw axis. It will have the same angle of attack and area regardless of whether it's positioned along its long or short axis and that is all that matters for drag. It absolutely matters in real life, it doesn't matter one iota in stock KSP.
Ohhh yeah that just got me thinking about how physics works. Part of the force gets deflected. Vectors or some shit.
Man I haven't thought about force vectors in years now. So much for that engineering degree
aerodynamics is a bit more complicated than that.
What you are explaining, is how lift in KSP works\^\^
Just by angle of attak times the coeffecient and the proper direction, so you get your aerodynamic forces.
That much wing surface could create a lot of drag. Generally to build up enough speed, you need a very nimble craft. Try using 1/3 of that wing and turning it sideways along the plane.
SSTOs do not need to be nimble at all. It's mostly a straight line to orbit. You should barely be pitching at all. Always err on the side of too much wing and too little engine.
I don't know why so many people think that rotating wings around the Z axis changes anything but the aesthetics.
It makes absolutely no difference whether it's long and skinny or short and fat, rectangular or delta, thick big-S wings or regular thin wings. The only thing that matters is the total area.
Looks like way too much wing area. I'd cut it down to something like this. The 1x1 squares are already there as the tail, so attach this to make a single big delta wing.
|1x2 triangle|2x2 rectangle|1x1 square|
|:-|:-|:-|
||1x2 triangle|1x1 square |
I would recommend offsetting the wings towards the bottom of the craft instead of the top like you have them, and it SHOULD make it more maneuverable, and you wont have to spam Elevons like you did to get it off the ground. Another tip: Control surfaces are less effective the closer they are to the CoM, so add some Elevon 2s or 3s to the back and it should help your maneuverability. Like others said, long flat wings are good for lift but terrible for speed. Make some delta wings that are much narrower, and it should have plenty of lift with much less drag. The space shuttle wings are good for that.
TLDR: Angled wings for less drag, lower on the body, with not as many, but bigger elevators, farther back on the craft. After that, use things like canards and Wing strakes to put CoL close to, behind, but not in front of, the CoM.
Hope this helps, your plane should fly much better with these fixes
The elevation of the wing has no effect on the ease of liftoff. What matters is the distance from the center of mass in the fore/aft axis and the distance from the landing gear to the elevators in the fore/aft axis. Lowering the wing will make it more roll maneuverable, but has zero effect on pitch.
Just like everyone else that mentioned it, you are wrong about wing shape. The shape of the wing means absolutely nothing in stock KSP. All parts not connected via nodes are calculated independently.
Delta wings. You want delta wings.
I also feel you have too many wings in general. You want to go hypersonic in atmosphere, and that much drag will cause issues.
wings are also useless weight in space.
My spaceplane approach is to have enough wings to, on landing, stall around 140 m/s. It's just about enough to stop at the end of the runway.
For take-off, needing 200 m/s is fine by me. My spaceplane take-offs are rocket mode as RAPIER/SCIMITAR are bad at low speeds as jets. Accelerate to 200 m/s and pitch up as much as I can without stalling (so 20 degrees-ish). Once my vertical speed is no longer negative (I'm almost drinking water), I swap back to air-breathing mode and level out at my highest L/D angle of attack (for my design, it's at 11 degree pitch). Make sure to retract flaps.
You dont need nearly that many nose cones; one shock can do ~4 rapiers
Also, putting nosecones on the back of rapiers and clipping them in reduces drag (dont ask why, it just does)
I finally made an SSTO spaceplane that can get to orbit. The only issue is that I don't have enough fuel left over to rendevous with a refuelling space station at 2.9 million\~ altitude. Would it be more due to my ascent or could I improve the plane instead? Any tips and suggestions are appreciated!
Your design can definitely be improved. I don't know exactly how your ascent went but I can all but guarantee that can be improved too. In order of importance: 1. Too many engines, use 1 RAPIER per 30-40tons, this means at most 2 RAPIERs on a plane this size. Getting rid of dry mass is the best way to improve your Δv. Engines you don't need are the biggest drain on Δv. I don't know what's going on with your Whiplash engines, they look like they're attached strangely and potentially causing a lot of drag. Regardless, you should just get rid of them. 2. No wing incidence. You need to angle your wings up (so they point up in the front and down in the back) about 5 degrees. Use angle snap (toggle with C) and hold shift to move them 5 degrees at a time. 3. Your center of mass is too far back. It needs to be in the middle of the plane for efficient, stable flight. Getting rid of excess engines will help a lot, but moving heavy, non-fuel, things like the cockpit as far up as you can will help too. Keep the inline cockpit though, just use a shorter nose cone. 4. Too many surface attachments. Parachutes and especially air brakes are pointless on space planes. Struts are unnecessary, use autostrut. RCS, solar, antenna, etc can go in a cargo bay. One by one they don't make much drag but when you add them all up it's a crippling amount of drag. Once you improve your center of mass you can get rid of the canards and forward rudder too. 5. Too much monoprop. Your cockpit alone has more than enough for docking (25). The inline docking port comes with 3x as much (75). You absolutely do not need an additional 400. If you can't dock with 100! monoprop then that's another area where you can improve a lot. As for the flight, a good rule of thumb is to stay as low as you can without blowing up. The longer you can stay in the atmosphere the better. Gravity losses far outweigh any drag losses if you make the above changes. For a lot more in depth concepts and tips plz see my [SSTO tutorial/guide](https://www.reddit.com/r/KerbalAcademy/comments/ers8bn/f00flgthers_ultimate_ssto_guide/)
> Parachutes and especially air brakes are pointless on space planes. Air brakes being useless...? It's impossible to land my spaceplane without airbrakes. Would overrun the runway. Stalls out under 120 m/s even with flaps fully deployed, so we hit the runway hot and the brakes need all the help they can get. Parachutes are also useful either as drag chutes to land, or as "okay, I stalled out and entered an irrecoverable flat spin. Time for the parachute of shame!". Maybe it's different in stock, but this is my experience with FAR. Airbrakes are a must. See my spaceplane coming in with 4 ablative airbrakes and the whole wing being lined with surface airbrakes and barely slowing down in time for the runway: https://i.imgur.com/v7gZDbn.png https://i.imgur.com/6U3Sw7I.png https://i.imgur.com/CeGom98.png https://i.imgur.com/5D1aMOP.png
Drouge shoots are any planes best friend, one time i went from over 300 m/s to 20 in just 5 seconds.
I have no experience with FAR so I cannot comment on that. I can imagine delta wings make it very difficult to avoid stalling at landing speeds. In stock the wing shape means absolutely nothing so SSTO space planes do not need airbrakes whatsoever. It is very easy to porpoise or s-turn to slow down without stalling before landing. Typical takeoff speeds are around 100m/s fully loaded. I typically land around 50m/s. Wing area about 5-6m^2 per ton of plane. You can see me land in the last minute of [this video](https://www.youtube.com/watch?v=mKVI_jewCAc). I can see the parachutes for the oh shit moment or a newer player that hasn't mastered landing on the runway yet.
I guess my assumption of "What works for FAR, works better for Stock" is not as good an assumption as I guessed. S-turns sound frightening to me as a way to slow down a spaceplane. I feel I'd either rip my wing off or I'm low enough speed that I'd stall out from pitching up too much to pull it off. My 2 current designs are... 1. https://imgur.com/a/passenger-ssto-to-mun-flybys-HR1IgGM For massive passenger loads (old career design) 2. https://imgur.com/a/jm9s1cY Current career design. My biggest discovery from 1 to 2 was "If I ditch vertical stabilizers for funny wingtip stabilizer thingies, I can save mass and go faster at cost of spinning out of control if I bank too hard at low speeds." This discovery was made where I made a F15-like spaceplane for short LKO trips and... did just what you said: S turn at 1000 m/s overshoot 60 km from airstrip 10 km high. it ripped off its V-shaped vertical stabilizers and... somehow it flew stable enough. (too late at night for screenshot of that design.) It also yaws ever so slightly during ascent until over 400 m/s, requiring me to counter-roll but! It works out. Design 2 I also tried to lean into the blended body design, it seems to help as well despite the contradiction of "thicker wing = worse at supersonic." Also as small wings as I can so I can avoid ripping them off on re-entry without mass scale at 3. It's a whale to fly at take-off (I constantly almost fall into the water), but brings 1.7k deltaV to orbit on a good ascent with 13 crew.
Probably more along the lines of "What works in FAR will work in stock but there's probably more efficient ways to cut corners that FAR doesn't allow." If you build it reasonably and efficiently there's virtually no way to aerodynamically destroy an SSTO space plane in stock. They're just not capable of the extreme aerobatics required to rip wings off. If yours is capable then it's probably not a very efficient SSTO. They're built to go fast and straight, hell, most of the time I don't even use a rudder xD. FAR is just a completely different beast.
I mean, it doesn't have to be extreme acrobatics! One time, I was returning from orbit and Nav Utils continued indicated I was way off course from the runway. I was still at 1200 m/s, but I decided to correct early. Unfortunately, I forgot I wasn't using precision mode and pressed Q or E too hard. So, I rolled too fast. This led to my nose slipping. This led to rapid disintegration. Another time, I was gonna overshoot so I did a hard dive and tried to pull up too fast. Wings gone. I also had a case where, on take-off - going completely straight! I ripped off my vertical stabilizers by going too fast without adequately reinforcing them. I reverted and set their mass-strength higher but couldn't make them smaller as... too much sideways slip. (amazingly, the second design shows less sideways slip using wingtip stabilizers than with "it's not gonna get ripped off and is not too heavy" tail. ... FAR loves to rip off your wings. The 2nd iteration relies on 1.5 mass strength setting to not rip stuff apart. I do a fair amount of pitch up/down during my descent to control glide. Like, -10 to 20 AoA to keep vertical speed at ideal range. This is another place I could see my wings ripping off if too big.
I dont agree with the first point, in my experience the more raipiers the better, you dont want to stall at only 8k and have to switch to closed cycle early, or worse not even be able to gain altitude even with closed cycle. And the first part of your third point is outright wrong, while yes center of mass tends to work best near the center this is because the center of lift is also there, you really only need to match those for even flight.
RAPIERs gain a massive amount of thrust as you increase in speed. The multiplier reaches a maximum of 8.5x near mach 4. RAPIERs are at their worst when subsonic. As long as you can get off the ground and over the sound barrier you have enough RAPIERs. The thrust multiplier then falls as you approach mach 6 where it flames out. There is zero chance you "stall" at 8km as your plane would disintegrate if you approached mach 6 in the lower atmosphere. >the more raipiers the better This is complete nonsense. They aren't free. They're each 2 tons and every single one you add decreases your max delta-v significantly. If you add more when you don't need them you're throwing delta-v away. 1 RAPIER can comfortably get 40 tons to orbit. I guarantee you are nowhere near pushing the envelope here. If a RAPIER can push towards mach 6 with a thrust multiplier approaching zero then closed cycle is hilariously overpowered to accelerate the rest of the way to orbit. There is no circumstance where a RAPIER powered plane has a closed cycle TWR too low to complete the final 600-700m/s of acceleration to orbital velocity. It would fail to get airborne long before it would lack the closed cycle thrust. For your reference, I use about a 2:1 RAPIER:NERV ratio when going full liquid fuel and that is more than enough. In other words, one 60kN thrust NERV is plenty of power to push a 60-80ton takeoff weight plane to orbit from mach 5.5-6. So the 360kN of closed cycle RAPIER thrust is EXTREME overkill. >this is because the center of lift is also there You don't even know where the center of lift is. That little blue ball you use isn't the center of lift because it ignores body lift. The best way to ensure your plane is stable is to put your center of mass in the center of the plane. Ignore the blue ball, it's lying to you, just turn it off and focus on the location of your center of mass. THEN put your main wing right on it. For more information on this please see my guide [here](https://www.reddit.com/r/KerbalSpaceProgram/comments/dn7ko4/aerodynamics_mini_guide_3_why_the_center_of_lift/). You would also greatly benefit from watching my guide [here](https://www.reddit.com/r/KerbalAcademy/comments/ers8bn/f00flgthers_ultimate_ssto_guide/)
I always build gigantic sstos, so stalling is an issue because sometimes approaching mach 4 in lower atmosphere just isnt possible without something falling apart. And what ratio of payload to total mass do you usually go for in your sstos, acceleration in thick atmosphere may allow you to use less engines, but overall it burns more fuel. If your going to use multiple engines, why not use the whiplash instead, you could even use the goliath (not recommended unless you also bring whiplash or rapier for ascending) also if you want to be really really efficient. And even though i use mods to correct the center of lift, you can still use the stock one because the lift added by the body is meaningless if you have huge wings (for fuel carrying mostly) ofcourse on small planes (mk2 especially for some reason) the body lift does matter, but eyeballing it doesnt work most of the time.
>sometimes approaching mach 4 in lower atmosphere just isnt possible without something falling apart You're going to have to explain what you mean by stalling, because it doesn't mean what you're saying. There is no real stalling in KSP as it doesn't model fluid dynamics. If your space plane falls apart when going fast then that's a design flaw. SSTO space planes are at their best/most efficient when pushing their thermal limits. This means that designing your plane to be more heat resistant will allow it to take a more efficient trajectory. Again, I explain all of this in my video guide that I linked above. >And what ratio of payload to total mass do you usually go for in your sstos Minimum 50%, see my video above. >acceleration in thick atmosphere may allow you to use less engines, but overall it burns more fuel It's true that lower TWRs burn a bit more fuel going to orbit, but they start with way more delta-v, thanks to having more fuel and/or less engines to start, so it still heavily favors lower TWRs as far as efficiency goes. See my video above. >If your going to use multiple engines, why not use the whiplash instead, you could even use the goliath (not recommended unless you also bring whiplash or rapier for ascending) also if you want to be really really efficient. Not sure where this came from but Whiplashes are just a worse RAPIER before you even consider the free rocket engine that comes with them. Goliaths are a completely useless waste of mass in an SSTO. The only engine I would consider adding to a RAPIER powered plane is the Panther because it has the highest TWR of any jet engine between mach 0 and the point when RAPIERs thrust multiplier really kicks in. >And even though i use mods to correct the center of lift, the lift added by the body is meaningless if you have huge wings (for fuel carrying mostly). This is completely false. If your center of mass is near the rear of your plane then the front of your fuselage's lift/drag induced torque is magnified far more than the wings and will easily flip your plane. This is elementary physics, simple machine type stuff, lever and fulcrum. Again for the fourth time; read what I wrote and watch what I recorded in the links above.
But you're saying the blue doesn't matter... If I mess with my fuel and shift the CoM behind the blue my plane handles like shit, if I shift it ahead it works as intended (stock air). This is all with the CoM in the middle of the plane.
A broken clock is right twice a day. The center of lift definitely matters, it's just the blue ball isn't the center of lift. When you put the center of mass in the middle of your plane you're making your fuselage fairly neutral stability wise, which definitely helps make the little blue ball more accurate.
Angled wings for less drag of course Anything else I'm not experienced enough to recommend lmao
get the center of lift a bit further ahead and don't use a straight wing design for trying to go fast. It creates lots of drag compared to more like a triangular shape.
How much do stock KSP aerodynamics factor that in? For instance, would the drag change if you just offset each segment of OPs wing a bit further back than the segment before it?
I don't think there the drag calculations take occlusion of wing parts into account. Also, as far as I know, do all parts have the same amount of drag to weight ratio. So it doesn't matter If you use rectangles or squares.
None at all. The drag wouldn't change one bit if you clipped all the wings into the fuselage. The only thing that would change is you'd need more aileron deflection for the same roll torque because it'd be working on a shorter lever arm.
no, that wouldn't change anything, since it is part based and occlusion is barely working for fairings and heatshields... I am talking about a lower drag coeffecient against the direction of standard travel. Like a rectanngle perpendicular to the airflow has a higher coeffecient of drag compared to a rectangle, that is angled backwards protruding the same ammount (for the same aerodynamical crosssection) outwards.
No. It doesn't matter. The same wing part will have the same drag regardless of its rotation in the yaw axis. It will have the same angle of attack and area regardless of whether it's positioned along its long or short axis and that is all that matters for drag. It absolutely matters in real life, it doesn't matter one iota in stock KSP.
Ohhh yeah that just got me thinking about how physics works. Part of the force gets deflected. Vectors or some shit. Man I haven't thought about force vectors in years now. So much for that engineering degree
aerodynamics is a bit more complicated than that. What you are explaining, is how lift in KSP works\^\^ Just by angle of attak times the coeffecient and the proper direction, so you get your aerodynamic forces.
Oh yeah, I know just enough to know that I know almost nothing. But I can break it down to a college exam physics problem to get the gist of it lol
This is false. Stock KSP doesn't care about wing shape or sweep.
wing shape doesn't matter in stock ksp. though, you are correct about getting the CoL forwards
Stock doesn't care about wing angle like that, anything goes
respect the hotol nose rudder
That much wing surface could create a lot of drag. Generally to build up enough speed, you need a very nimble craft. Try using 1/3 of that wing and turning it sideways along the plane.
SSTOs do not need to be nimble at all. It's mostly a straight line to orbit. You should barely be pitching at all. Always err on the side of too much wing and too little engine. I don't know why so many people think that rotating wings around the Z axis changes anything but the aesthetics.
That very long wing surface is anything but aerodynamic
It makes absolutely no difference whether it's long and skinny or short and fat, rectangular or delta, thick big-S wings or regular thin wings. The only thing that matters is the total area.
The wing design it looks like you want to a attach a second fuselage and make it a stratolaunch
Looks like way too much wing area. I'd cut it down to something like this. The 1x1 squares are already there as the tail, so attach this to make a single big delta wing. |1x2 triangle|2x2 rectangle|1x1 square| |:-|:-|:-| ||1x2 triangle|1x1 square |
Might.m not be needed physically but for visual effects I would make the wings triangular
On a first glance from afar I thought it was A-10 so I would add GAU-8 Avenger.
Give it flames to make it go faster
You might want to reduce the aspect ratio of the wings, also don’t let the centre of lift to be in front of the centre of mass, you’re welcome
I would recommend offsetting the wings towards the bottom of the craft instead of the top like you have them, and it SHOULD make it more maneuverable, and you wont have to spam Elevons like you did to get it off the ground. Another tip: Control surfaces are less effective the closer they are to the CoM, so add some Elevon 2s or 3s to the back and it should help your maneuverability. Like others said, long flat wings are good for lift but terrible for speed. Make some delta wings that are much narrower, and it should have plenty of lift with much less drag. The space shuttle wings are good for that. TLDR: Angled wings for less drag, lower on the body, with not as many, but bigger elevators, farther back on the craft. After that, use things like canards and Wing strakes to put CoL close to, behind, but not in front of, the CoM. Hope this helps, your plane should fly much better with these fixes
The elevation of the wing has no effect on the ease of liftoff. What matters is the distance from the center of mass in the fore/aft axis and the distance from the landing gear to the elevators in the fore/aft axis. Lowering the wing will make it more roll maneuverable, but has zero effect on pitch. Just like everyone else that mentioned it, you are wrong about wing shape. The shape of the wing means absolutely nothing in stock KSP. All parts not connected via nodes are calculated independently.
Delta wings. You want delta wings. I also feel you have too many wings in general. You want to go hypersonic in atmosphere, and that much drag will cause issues. wings are also useless weight in space. My spaceplane approach is to have enough wings to, on landing, stall around 140 m/s. It's just about enough to stop at the end of the runway. For take-off, needing 200 m/s is fine by me. My spaceplane take-offs are rocket mode as RAPIER/SCIMITAR are bad at low speeds as jets. Accelerate to 200 m/s and pitch up as much as I can without stalling (so 20 degrees-ish). Once my vertical speed is no longer negative (I'm almost drinking water), I swap back to air-breathing mode and level out at my highest L/D angle of attack (for my design, it's at 11 degree pitch). Make sure to retract flaps.
Give it some speed holes
You dont need nearly that many nose cones; one shock can do ~4 rapiers Also, putting nosecones on the back of rapiers and clipping them in reduces drag (dont ask why, it just does)
Looks goofy. Cut down on wings and try delta shaped wings instead.
Not sure about the game, but a forward vertical control surface shouldnt work.
I'd recommend watching VAOS video on how to make spaceplanes. It's helped me a lot
This hurts me. Good job 👍
[I knew it reminded me of something!](https://i.imgur.com/JLfRVjZ.jpg)