Temstar

Yes, it's true. But how does that relate to the M2 Bradley? The M1 Combat Car was designed to do the job of being a calvary tank, it was bad at it but that just made it a rubbish tank. M2 Bardley was designed to do the job of an Infantry Fight Vehicle, it's actually very good at that. Being an IFV meant it had to have features that specifically make it a very terrible tank if you try to shoehorn it into that role - for example the lack of Explosive Reactive Armour.

What's your point? That it uses .50cal and .30cal as its weapons? That's sort of par for the course for that time period, for example: https://en.wikipedia.org/wiki/Panzer_II Has a 20mm autocannon for a main gun The M1 Combat Car is explicitly designed to NOT to work with infantry, as the 72km/h top speed shows. The thinking at the time was that for infantry tanks that are designed to attack along side with infantry a top speed of about the same as human walking pace was enough. Then you need really fast calvary tanks to dash along and exploit openings in the enemy line. M1 Combat Car is decidedly a calvary tank given its very high speed for its time. Of course since calvary tanks are charging around the battlefield they are going to run into calvary tanks from the other side who's also doing the same, and it was immediately obvious to everyone that a 50 cal was way underpowered when it was potentially running into things like BT-2 which was just as fast but had a 37mm gun, or even worse the slower T-26 with a whopping 45mm gun.

No the battle field role between the two are extremely different. For one thing IFVs are specifically design to work along side squads of infantry, where as troops are suppose to stay far away from MBTs when they do their thing least they get fragged by MBT's reactive armour. Calling IVFs "tanks" is as wrong as calling sell-propelled gun tanks. They may look kind of similar to a tank if you squint at them but they are designed for every different jobs.

For large cargo SSTO with medium TWR I climb at 5 degrees up angle pretty much all the way. For low TWR you still climb the same way, but around the sound barrier you need to do a shallow dive in order for the engines to gather enough ramjet power to break mach 1.

It's not that Moon was made from Earth material after Theia impact, it's more both Moon and Earth was made from material that came out of the proto-Earth / Theia impact. Proto-Earth for example had a smaller iron core than our Earth today. Our big iron core today which produces the nice strong magnetic field that protect us is the combined product of both cores from proto-Earth and Theia.

Buzz Aldrin advocates for this winged booster design:http://buzzaldrin.com/space-vision/rocket_science/starbooster/ The core won't be reusable but the boosters will be. Yours truly was inspired by the Energia II design and came up with this in KSP: Recovery of engineless ET is probably not very viable in real life. My vehicle in KSP is SSTO mainly because KSP can't deal with vehicle recovery in the atmosphere. Those StarBoosters seems to separate while they are still suborbital.

Mk3 has an advantage over 3.75m because it has an insane 50m/s crash tolerance vs 6m/s for 3.75m part, Mk3 also has very high max temperature. Even so it's perfectly possible to use 3.75m tanks as structural elements as the above picture of the Aurora Winged Booster shows. Anyway, it sounds like you trouble is mostly with the actual touch down right? We can work on this. Here's two screenshots of touchdown, pay close attention to the horizontal and vertical speed on the top centre of the screen (this is part of KER's HUD display) 40 ton SSTO touching down, Mk3 based fuselage. 42 ton winged rocket touching down, high wing load, mixed Mk3 and 3.75m fuselage. Okay so the main thing you have to manage when touching down is vertical and horizontal speed. You want to hit the deck at less than 10m/s vertical speed, preferably less than 5m/s. You do this by getting your horizontal speed to around 80-100m/s just before touching down, then before you hit the deck you flare (pitch up), trading away horizontal speed for vertical speed. Here's a chain of screenshots showing the flare process for that big winged booster: Horizonal speed is important because it governs how your craft will behave when you flare. Too slow and you will stall and fall on your ass. Too fast and you will start to gain altitude instead of land, you will also lose air speed and probably then stall. The exact value depends on how well your aircraft can glide - a glider will have very slow landing speed while a fly brick of a shuttle need very high landing speed.

Isp is actually quoted in seconds in real life too and the reason for this is again those silly Americans. Basically if the entire world used metric then you would simply quote exhaust velocity in m/s. But since US still like to measure speed in fps (feet per second), and US is kind of big in rocketry it would be useful if we can quote the efficiency of rocket engines in a unit that does not care if you use meters or feet. So people decided to divide the exhaust velocity by standard gravity (9.81m/s2 or 32.2fps2, whichever system you work in it doesn't affect Earth's mass!) and the result is a number with the unit of seconds. And since Americans and rest of the world are in agreement over how long a second is we can then compare engine performance directly without messing with unit conversion. Divide exhaust velocity by standard gravity gives you specific impulse. The "specific" part refers to the fact that this is specific to Earth's standard gravity. Specific impulse does have a physical interpretation, I believe it's "the number of seconds the engine (assuming massless) can hover over Earth's surface holding up a 1kg weight while being supplied with 1kg of fuel", or alternatively "the number of seconds the engine (assuming massless) can hover over Earth's surface holding up a 1pound weight while being supplied with 1pound of fuel". As you can clearly see with the physical interpretation, your unit of mass is irrelevant, only your engine exhaust velocity makes a difference.

I say about 75% of the time I use an established booster, so my subassemblies are mostly launch vehicles. There's often some fine tuning involved to better fit the LV to the payload - eg making SRB from twin symmetry to triple symmetry so the LV can carry a slightly bigger payload than what its rated for. The other 25% of the time I design custom launch vehicles for unique payloads. If the custom launch vehicle has particularly satisfying performance then it gets added to the subassembly list.

It wouldn't be gas core lightbulb if it wasn't OP. I submit to you that it's simply not possible to balance advanced nuclear rocket engines against chemical - fission fuel energy density is so many orders of magnitude better than chemical that no matter what you do chemical rocket engines will always look feeble against them. The mod lightbulb is already much weaker than real life projection of what a gas core engine can do. When you sign up for Atomic Age you're implicitly saying "my Kerbals have advanced to a technology level where they would look at a chemical rocket powered interplanetary ships the same way we look at a steam locomotive - quaint, romantic, not very practical".

Nothing says spaceplane can't have rocket engines, or jet engine, or both, or combined cycle etc etc, hence why I said spaceplane and not say, jet plane. Similarly rockets can have both rocket engines and jet engines. I'll argue the main thing that separates spaceplanes from rockets is not the engine but weather or not they make use of aerodynamic lift. The space shuttle stack at lift off for example I would define as a rocket, where as when the orbiter returns to Earth that would be a splaceplane. I know there's a grey area in the middle, that's why I made the "hybrid" choice for those who's not sure if their preferred launch vehicle can neatly fit into either group. If you preferred launch vehicle is something like the space shuttle I would say you should choose hybrid.

If you haven't noticed, we get far more questions on the forum from people asking about spaceplane aerodynamic problems than people asking about rocket aerodynamic problems. Now of course, part of that is to do with the fact that spaceplanes on the whole is much more complex than rocket, but given that for a long time now Squad has been focusing on spaceplane parts lead me to think perhaps spaceplane is actually in fact more popular among the target audience, and that's what this poll is intended to find out. Keep your whining about "Squad is not paying enough attention to rockets!" to a minimum in this thread - Squad only has so much manpower, and they've already promised that rocketry is going to get a look at after 1.1.

One way is to reduce the plane's tendency is to snake is to go full pitch up as soon as you start accelerating on the runway, rather than wait for you to reach rotation speed then pitch up. Pitch up causes the lift generated to put a greater proportion of the plane's weight on the main gears and so decrease the load on the front gear.

No, you're accelerating towards CoM at 9.8m/s2 (or whatever the value is for your local gravity), but your distance to CoM remains constant for a circular orbit, which by definition means you have zero velocity towards the CoM at any instant. Remember, gravity is an acceleration and speed is... speed. Acceleration is measured in m/s2 and speed in m/s.

LOX is still potentially useful for NTR if your NTR engine is a LANTR engine. A LANTR NTR is a regular solid core NTR with an amusing "afterburner" stage where LOX is optionally injected into the hydrogen steam after its shot out of the reactor. The LOX then reacts with the super hot hydrogen to further increase the exhaust temperature slightly which goes some way to offset the Isp disadvantage from high molecular mass exhaust. Basically on "LH2 only" mode the LANTR behaves as a normal solid core NTR with the ususal 800-1000s Isp. When it runs on "afterburning" mode the Isp drops to something like 500s but the thrust increases a lot because of much high mass flow, with the final result that you get more delta-V per unit of water split by your ISRU kit running on afterburner since you are no longer throwing the LOX away. Plus high thrust makes the engine better at taking advantage of Oberth effect. But if the amount of water harvested is not an issue than throwing the LOX away and keeping only the LH2 gives much more delta-V for the same vehicle wet mass. Having LANTR gives you flexibility to fine tune LOX/LH2 ratio to optimize for a particular mission.

One other reason is lift behind CoM. So we all know that for inherit stable plane you need CoL behind CoM. Unfortunately that means when you accelerate down the runway on your tricycle landing gear the first bit of lift your wings generate lighten the load on your main gears and in effect shift almost all of the unsupported weight of the plane to the single front landing gear. This turns the plane into something like one of those single wheel wheelbarrows and those are known to snake all over the place when not controlled well. Conventional landing gear (two big wheels in front, one taildragger behind) will not have this problem.

Horizontal speed will not be constant (from surface of Earth reference frame) because the direction of "down" is constantly changing. Remember acceleration is towards CoM of earth (assuming spacecraft of negligible mass relative to earth), and that acceleration's direction is constantly changing (again from earth reference frame) because the spacecraft is moving. Horizontal speed and direction of acceleration are only constant from spacecraft reference frame.

It does though, After 1/4 of an orbit the direction of your motion is now 90 degrees different from your starting position. If the Earth still has its normal CoM but is instead a flat plan you will hit the ground vertically at orbital velocity.

Because at a very special horizontal speed the surface of the Earth curves away from you at the exact same rate as the 9.82m/s acceleration downwards acceleration is pulling you down by. If you have less speed than this, then you fall down faster than the Earth is curving away from you, hence why you loose altitude.

In thin tubes surrounded by neutron absorbing material so the uranium don't start the party until it's time. It's 2% solution of uranium salt, so 98% of the propellent you shoot out the back is water. Being basically a continuous nuclear explosion the Isp of a NSWR will be something like 479,103s for the 90% enriched version. Zubrin says the engine can survive this as peak neutron flux will be outside of the nozzle and he says the engine will have a ring of water jets (just water, not nuke juice) firing water next to the wall of the engine to create a film to project them. But then again it's Robert Zubrin, a person known to be too optimistic with his designs.

I want to say something about this. There's nothing stopping you building a craft that launches vertically like a rocket, then recover horizontally like a spaceplane. Launching vertically has the advantage that you no longer have to worry about things like tail strike and rotation speed and runway not long enough and so on.

Like say, mix the water with 90% enriched weapons grade uranium-235 salt, then you'll really get some Isp! Zubrin's funny drive aside, I think in the original Project Orion there were ideas to use water ice harvested from Enceladus as propellant for coming back to Earth. As in, you pack all that ice around each bomb so that when they go off, the water plasma will then hit your pusher plate. It won't be as good as tungsten that will be used for the bombs leaving Earth but using ISRU means you only need to bring the bombs for the trip home and not the propellant for the bombs.

What, that's not true. Here for example is my true SSTO tanker that I use to refuel LKO: If I burnt that fuel instead that would be a lot of delta-V. Here's a cargo carrying variant, releasing two full ore tanks: I'm more of a rocket person but for these sort of mundane surface to orbit jobs I use my SSTOs to save cost. But then again I play on hard mode so maybe I'm just a masochists.

But then by default all my reentry airbrakes will be deployed when my rocket load, and I have to wait for them to slowly undeploy before I can launch. Worse, some rockets could have been setup with the geometry so that on the pad, if you deploy the airbrakes they will shove aside the boosters around the core and cause rapid unscheduled disassemble, the assumption that the airbrakes are reentry aid and you will never deploy them until reentry when all the boosters are long gone.

Tell the crew to get out and push, won't take much pushing if you're already skimming the atmosphere.