• Content count

  • Joined

  • Last visited

Community Reputation

810 Excellent


About AeroGav

  • Rank
    Rocketry Enthusiast

Profile Information

  • Location UK

Recent Profile Visitors

4,795 profile views
  1. AeroGav

    SpacePlane Reentry?

    This is the airplane and here is an exploded view of the mk1 fuselages attached either side of the main body On stock settings, unless you're re-entering at 5000 m/s from a Jool trajectory, only the Kerballed bits are at risk and the cockpit in particular. Clipping stuff inside the structural fuselages does not hide them from drag or heat, the game still sees them as radially attached stuff on the outside of the ship, regardless of how you offset. And that stuff will make huge drag btw. Just swap to an inline cockpit and if that's not enough, increase wing area so you can make more lift and drag on re-entry. Lift keeps you out of the thickest atmo till you've slowed up a good amount, and drag obviously reduces your speed and therefore heat too.
  2. AeroGav

    Planes for alien skies

    Helecopters can never manage a particularly high forward speed - possibly you are encountering "retreating blade stall" which is why it loses control. That said, if you can get up to 30-40km the ISP of stock engines dramatically improves. I built a NERV spaceplane that could make the ascent from these altitudes to orbit if hypereditied there. However, nuclear turbojets make it all much easier.
  3. AeroGav

    SpacePlane Reentry?

    I'd be interested to see what your design looks like @Lego_Prodigy I never use the pointy cockpits (like the one in your avatar pic) because the part at the front gets most of the heat and the cockpit is the most sensitive to heating. In 1.3 heating effects made pointy cockpits more or less useless for Spaceplanes, in 1.4 heating levels have been reduced but still the first thing i'd try is to swap to the mk2 inline cockpit with a mk2 to mk1 adapter in front then a nose cone or intake on the front of that. In fact you could even put a mk2 clamp o tron ahead of the cockpit. For re-entry profile, I usually come in pitched up moderately with the nose 10 degrees above prograde. That way you're not completely stalled and are still making lift, which keeps you in the thin air longer. You also have more control that way and can fine tune your arrival point by pitching up for more drag (if overshooting) or lowering pitch to 5 degrees for best glide ratio (if coming up short). This all works better when you have a lot of wing. I normally retro burn until my PE goes to ground level somewhere in the desert continent west of KSP, my planes have good / lift drag ratios and when they encounter significant atmosphere the impact point inevitably starts moving downrange. BTW, are you dumping your payload after launch and immediately re-entering, or are you orbiting in orbit a little while first? It is harder to re-enter if the cockpit is still heat soaked from the launch process. This video demonstrates the landing point aim process mostly - but you can see how even a mk1 design has no problems with heat when using inline cockpit. Make sure you have subtitles / captions enabled for the text (think that only works on a pc tho)
  4. AeroGav

    Planes for alien skies

    Interstellar is a huge mod that takes a lot of supporting, and i think it has balance issues. But if you want to go to Eve, it has something you absolutely need for this - dual mode nuclear thermal engines that can function as nuclear turbojets (running off eve's atmosphere below mach 3.5) and then operating as a traditional nerv in close cycle mode. Use a 2.5m pebble bed reactor and hydrazine or ammonia fuel for best results ! Stock, I have various spaceplanes able to land on Duna. Pure aerodynamic lift like a Fieseler Storch - I have not actually flown this to Duna but I'd be amazed if it couldn't land there. As for getting there, it took off from the rooftop and got to orbit with enough Delta V to reach Duna, if not come back without some refuelling Here is a 5 seater IRSU plane that could straight shot Duna in 1.3. I haven't tried it in 1.4 since fairing drag is bugged, it might not go so well.... This one uses Vernier lift engines to reduce landing speed on Duna, as you can see from the first part of this video, you can also land on Minmus flats with them.
  5. AeroGav

    kerbal SSTO program!

    I've played career games this way, but with standard difficulty it is harder to get tech than to get funds, and what funds are required are mostly spent on upgrading facilities than on vehicles. For any given mission, it requires a larger (more facilities) or higher tech vehicle to accomplish with re-use rather than 100% disposability. Plus, landing all those re-usable craft eventually becomes a chore in itself. Suggest you create a custom difficulty game and Lower Funds Rewards to 30%, as well as Funds penalties to 30%, then give yourself just enough starting tech to unlock aviation. Lowering Funds Penalties reduces cost of building upgrades , so they are no longer the major expense , and cuts down the grind. However lowering Funds Rewards means you get less money per contract and have to shoot for 100% re-use on most flights if your space program is to be profitable. As for the airplanes I use : Juno / Terrier 4 junos and a terrier, just gets to orbit with tight margins. Panther / Terrier Still rubbish payload fraction, but a lot less sweaty. Simple 30 part low orbit tourist ship Something that can actually tow station components to orbit behind itself (no cargo bay) Panther and Poodle, self launching science lab - Panther / N.E.R.V Now you're in business. Worthwhile performance possible. Here's the basic Voodoo Ray possibly able to put flags on Minmus, it will certainly do Munar flybys with ease. It is very stable aerodynamically and can be flown by non-pilot Kerbals. Here's a stretch version of the above, with larger wings and fuel tanks. A bit slower getting to orbit but enough fuel to get you to the Mun surface and back. I To reduce drag and to make the lower TWR easier to manage, the wings and control surfaces are angled such that you just use Prograde Hold in Surface mode for the flight to orbit, minor adjustments to climb rate can be accomplished by action groups 1-3 which deploy nose/up down trim flaps. Whilst none of the parts are higher tech than the basic Ray, it requires a trained pilot for the Prograde hold mode and that your Hangar supports custom action groups. The longer wingspan may not be launchable on the basic runway either. The final Panther/NERV jet is this dinky little mk2 with a small cargo bay. Can deploy small satellites but with an auxilliary fuel tank, could also get you to the surface of Minmus pretty easy (then drive it as a rocket rover over multiple biomes to max your tech tree) Whiplash / DART / N.E.R.V The NERV is a 500 tech point part, and overall i can do more with a Panther/ nerv than i can with a Whiplash/Terrier. But If you have both 500 tech nodes, you can make something nice like this -
  6. AeroGav

    Fuels in KSP

    The Russians converted an airliner to run an engine off one, search for "cryoplane". Jet engines can run off any combustible fluid, I've seen some youtube videos from a Canadian guy who refurbishes old jets for use as ground power plants, if you want to run off Natural Gas, Gasoline, Kerosene, Diesel or even waste vegetable oil (how good would that smell) you just change the fuel injector nozzles to account for the viscosity of what you're injecting and that the engine gets the right amount of fuel. Certainly less involved than converting in internal combustion engine to run off a different fuel - lower octane ratio, would have to put a spacer between engine block and cylinder head to lower compression ratio, something with higher boiling point than gasoline? would need to worry about your carburettor failing to vapourize the fuel etc. Biggest problem with liquid fuel being hydrogen, is that you'd never get a worthwhile amount in big s wings and strakes like you can in game. Also with that huge surface area to volume ratio, boil off rates would be insane. also , ice forming on wings of aircraft is generally considered a bad thing, so filling the wings with cryo propellant probably not smart,
  7. AeroGav

    Fuels in KSP

    Most of the cost issue is down to people using NTR for deep space probes. Obviously if you're not recovering the part, the price hurts. That said, since the NTR will be on the upper stage, it really should be possible to recover the entire upper stage at the end of the mission , though the re-entry aerodynamics and parachute landing attitude will need careful design. I only really use them on space planes and shuttles, so the recovery of the engine is a given (and necessary delta v would be hard to achieve otherwise). Though some of these nuclear spaceplanes aren't SSTOs, discarding jet engines or riding up to 20km on SRBs
  8. AeroGav

    Fuels in KSP

    But Methane leads to soot deposits within the reactor doesn't it, which precludes us from using the engines the way we do in KSP (over and over with no maintenance, for decades on end, in an IRSU grand tour) The values given for Ammonia and Hydrazine as NTR fuels vary a lot depending on what source you're quoting and on the reactor temperature (degree of dissociation). Remember though, we're not comparing their values with Hydrolox, an Ammonia/Hydrazine NTR is competing against storable chemical propellants, that give between 310 sec (Space Shuttle OMS) and 375 (SpaceX Raptor, as yet unbuilt, if you treat mild cryo Methalox as "storables")
  9. AeroGav

    Buff Rapier vacuum Isp

    You can see why the RAPIER is such a good jet engine even if you're not using close cycle mode. The thrust multiplier remains above 3 till mach 5.5, given that orbital velocity (at stock scale) is about mach 7, you only need 1.5 mach's worth of rocket delta V. The Whiplash may have 20% better fuel consumption in the air breathing phase, but it drops to a multiplier of 3 by mach 4.5, which means you need 2.5 machs worth of rocket delta V. Even if you are using LV-Ns, rocket mode fuel consumption is 4x that in air breathing, so you can see why the Rapier's higher top speed always wins. Well, there are other fuels that an NTR can run off than LH2. For example, Ammonia (which can also be used in jet engines). Liquid ammonia is a storable propellant. It won't give you anything like the ISP of NTR / LH2 (though it does partially dissociate to hydrogen in the heat of the reactor) , but it's still heaps better than storable chemical propellants. The main thing is that large LH2 tanks mean drag, which is worse on a space plane than a rocket. BTW, in this game rocket engines correctly attached give very little drag, even if you don't clip nose cones into their rear attach nodes. The vast majority of the drag is coming from the fuselage, ie. the LFO tanks of your thirsty closed cycle RAPIERS. Sounds like the best compromise would be to give it the Vacuum / Atm closed cycle ISP values of the Dart aerospike, and to reduce this flow multiplier to 1.5. People will have to use a proper flight profile. You can still hit the same airbreathing top speed, but you'll need to do that in level flight at high altitude, not while passing through 8km in a steep climb. Flights to orbit will take a minute or so longer, but if you don't like flying, why are you building space planes. I'll have to redesign my craft to incorporate more RAPIERs, but will probably start using Oxidizer again and fit fewer NERVs/Panthers.
  10. AeroGav

    Buff Rapier vacuum Isp

    You are correct in that the SABRE, unlike the RAPIER, has a plug type nozzle that gives decent performance across a wide range of air pressures, purportedly not far below the state of the art in terms of vacuum isp. The problem is you are going to hard time attracting support from the community because it is already seen as one of the most OP engines in the game. You'd really have to package this up with a set of nerfs to address the following : The Rapier should require liquid hydrogen. LH2 has more heat absorption per KG than even water, no other fuel comes close in this regard. This means to have a RAPIER you have to deal with boil off and more importantly, very bulky (draggy) fuel tanks. Without LH2, the use of fuel to pre-cool the intake air - the thing that differentiates it from a Whiplash - is not viable. The Rapier gets this crazy ramjet boost to max thrust at high speed, peaking at over 8 times the static thrust rating at mach 3.7. This is not a feature of the real SABRE and seem to ignore flow limits of the intake/precooler/compressor systems, rpm limits of the turbines and max chamber pressures. This banzai surge from mach 1.5 - 4 makes possible the blatantly unrealistic flight profile of flying level after takeoff and accelerating to mach 4/5 at sea level, before pitching up and holding a constant pitch angle till clear of the atmosphere. The fact that thrust goes to near infinite levels, allows the massive drag to be overcome. In reality no aircraft has gone more than a hair over mach 1 at sea level. Any airframe that generates enough lift to get airborne before the tyres explode will be too draggy to push high speeds at sea level. At altitude, it's a different story. Same with the SABRE engine - the ram air effect of increasing speed compensates for the thinning air at altitude, but will not allow it to greatly exceed its sea level thrust due to choke limits. The pre-cooling deals with adiabatic heating, up to a point. Doing both of those would require major changes, but they should perhaps give the RAPIER a much flatter thrust curve in its config files, to at least acknowledge the above, if they're going to buff the vacuum ISP like you suggest. That will still break a load of legacy craft files, but then that's something with come to expect with version updates ! My preferred propulsion is now one Rapier , one Panther and two NERVs per 40 tons of craft weight. I don't use the close cycle mode at all. Can only see it making sense in edge cases like what Matt Lowne does with RAPIER SSTO lifting an ION system into orbit. I can get better payload fraction going liquid fuel only (mass of the nervs more than offset by absence of massive LFO tanks) but RAPIER only gives lowest dry mass, which enables the Xenon drive payload to get more delta V.
  11. AeroGav

    Fuels in KSP

    Monopropellant Hydrazine fits the bill, unless anyone can think of a reason to look further Liquid Fuel It's far too dense to be Hydrogen It doesn't give nearly enough ISP to be Hydrogen (450 top end chemical, over 1000 NTR) It can be stored indefinitely It does not cause soot clogging of NTRs with prolonged use (so not Methane or Kerosene) It can be used in jet engines Not particularly explosive. No sustained ground fire when the container is destroyed My theory is that it's Liquid Ammonia. This stuff can burn in air in air breathing engines (though it only has half the calorific value of kerosene) and it can be reacted with storable oxidizer in a chemical rocket. In an NTR, some of it dissociates to hydrogen, giving moderately high ISP. In a crash, you really don't want be breathing the vapours of this stuff, but then the same goes for Hydrazine. It probably helps our little green friends wear space suits, but then again they seem to be made of strong stuff all round. Oxidizer Storable Nitrogen Tetroxide?
  12. AeroGav

    Made a table for wing effectiveness [WIP]

    Max deflection does not come free. The higher the angle of attack of the control surface, the more drag it produces. Eg. Airplane is at 3 degrees angle of attack Wing is mounted to fuselage with 5 degrees of incidence Aileron on wing deflects 10 degrees That aileron is now at 3 + 5 + 10 = 18 degrees At small angles, you get mostly lift, but after a point lift starts to max out but drag goes up exponentially. This is especially important with regard to ailerons because the drag at the wingtip torques the nose away from the direction you're trying to turn in (adverse yaw/sideslip). Of course, you can take a surface with a low max deflection angle and crank its "authority limiter" slider up to 150% if you want to turn it into a highly deflecting one, or take a highly deflecting surface and turn the authority right down. I love Big S wing strakes, i try to keep all my fuel there if i can. Orange tank to orbit on a really dinky liquid fuel lifter - ...and yes, if your computer can bear the part count, don't use real tail fins, mount big S strakes vertically like in the above example then put elevons on the end for the active part of rudder functions. Here's another convert to the Way of the Big S Strake p
  13. AeroGav

    How do you get a bunch of kerbals around?

    This is overall the best spaceplane i've built so far, tested in 1.4.2. 11 Seats and 3000dv in low kerbin orbit. Has an inline clamp o tron and twin reaction wheels, but it wouldn't be particularly easy to dock to a station. Since i'm bad at docking, i'd probably put some kind of tender in orbit next to the station, some non aerodynamic thing with docking ports and 4 way rcs blocks to move the crew the last 100m from the station to the airplane. You could try to improve the docking maneuverability of the airplane but RCS ports add a lot of drag - if you must do this use one Vernier or linear RCS port for each axis, mounted on the CG, not the draggy and melty 4-ways. Even then , the inline clamp o tron makes it better as a thing to be docked to , rather than a thing doing the docking. Yes, people put shielded clamp o trons on the front of spaceplanes but that adds even more drag. You can overcome that drag with the raw power of a chemical fuelled ship where every engine is a rapier, but then running out of fuel becomes the issue. SSTO rockets are a few minutes quicker to orbit than a space plane, but it ultimately turns into a race against your fuel gauge the margins are so thin.
  14. I built this Andromeda class SSTO the other week, the intended use being space station components, which are bulky but light. I tested it with a 2.5m Xenon powered ship as the heaviest plausible payload (18t), because if your lifter is NERV powered, why would you go back down to chemical ISP for the deep space part? But the gold standard for a mk3 SSTO is an orange tank (36T) , so it had to be done... A design like this lives or dies by it's lift/drag ratio, namely you must stay as close to prograde as possible to minimise drag from the cargo bay. Aerodynamically, it's designed to do that when empty, and i've added trim flaps on action groups 1-3 to nudge the angle of attack a few degrees higher or lower so you can adjust the flight path. However, the positioning of the cargo can upset this. The orange tank caused it's AoA in Neutral trim to shift to almost 2 degrees nose down , due to the cargo being slightly too far forward. I was able to work around this by operating with nose up trim most of the flight and tweaking the deployment angle of the trim flap, as i'm sure you could if you had the luxury of an analog stick ! In future though, i'd recommend test flying with the payload before shooting for orbit, and see where the natural AoA goes to so you can see if the cargo needs to move at all. Or just get a fancy-ass analog joystick ! Is it the smallest thing to ever lift an orange tank?
  15. AeroGav

    Landing Gear Weight limits.

    I seldom economise weight on my space planes, with the NERVs I like to carry, a few kg for the landing gear seems moot, though i focus hard on drag. The limiting factor for me is elimination of tail strikes. Even the big S wing part has quite a short span - in order to get enough area, I find myself mounting two back to back in a double diamond or attaching strakes. The wing root therefore runs most of the length of the fuselage. When you add 5 degrees of incidence, this means the trailing edge is often the lowest point of the aircraft and it's right at the back of the plane too, raising the tailstrike risk. You can't shift the whole wing upward because fuel is stored there and that results in centre of thrust issues/CoM shifting as the fuel burns off. So, even my smaller designs tend to use medium main landing gear legs. 40 tons gross weight on that thing - probably doesn't NEED mediums