Starlionblue

I mean the Transonic Design tab graph. Doesn't look too bad. What I'm noticing is that your pitch angle and AoA are equal. This indicates that you are deriving all your lift from AoA and nothing from the shape of the wing. Think paper airplane. Is there any way you could camber the wings and/or give them an angle of incidence? Most real world designs have angles of incidence around 2 degrees. I don't know how much improved area ruling would decrease wave drag, but it might be worth a shot to optimize this.

Cool pics. Lovely aircraft. It makes sense that AoA is higher just after rotation, at low speeds. What also makes sense is that L/D is better with a lower AoA at high speed compared to a very high AoA just after rotation. The high AoA gives a lot of lift, but it also has a very detrimental effect on drag. Can you post a screenshot of the Ferram lift graph thingy for, say AoA 3 degrees?

When you say AoA, do you mean angle of attack or pitch angle? What is the actual AoA readout? You can get this from debug menu AeroGUI or Ferram itself. Screenshots of the plane in flight?

"The most variable variable". Love it! Also we have to assume level flight in all these cases since otherwise we have to bring in thrust or weight components. And that's just complicating things.

Warning, long and rambling post ahead... First off, you're reading the table wrong on ConcordeSST wrong. L/D for Concorde was around 12 in high subsonic cruise at M0.93. In supersonic cruise the L/D is around 7. However that doesn't explain the issue. Lift The lift of a wing follows the lift formula where lift is equal to the lift coefficient (CL) x half of density (rho) x true airspeed (V) squared x the wing area (A). Importantly, the lift coefficient Cl includes angle of attack. In your case wing area does not change. True airspeed is obviously lower at takeoff than in supersonic cruise. Density is higher (unless you're cruising at ground level). Thus higher lift is explained either by higher density or higher Cl. Drag The drag equation is very similar, except drag replaces lift and coefficient of drag Cd (in this image just C) replaces Cl. Again, density (rho) is lower in supersonic cruise, while true airspeed is higher. Cd includes angle of attack just like Cd. Angle of attack may be your culprit Knowing the angle of attack in the various regimes would be useful. Angle of atttack has a massive effect on both lift and drag as you can see in the graph below. (Note the graph is just for a typical airfoil. Wonky stuff happens in the transonic and supersonic regimes.) Unlike pretty much any other airliner, Concorde did not have high lift devices, making it uniquely dependent on angle of attack to increase lift. This is clear when you look at pictures on approach. Very high pitch angle, which made for lots of noise, high power levels, and the need for the drooping nose to maintain visibility. Ideally, should take density out of the picture by staying at one altitude in all maneuvers. Not the easiest I know. For a given mass, density, wing area and true airspeed you need a given lift. If mass increases with the same speed, density and wing area, angle of attack must increase in order to maintain the same energy state.

Thanks for input. Much appreciated. I can use dynamic pressure as a (manual) input for thrust control. However given rocket configuration changes during climb, the ideal number changes because terminal velocity is specific to the configuration. As side boosters are shed, terminal velocity seems to increase, and thrust should ideally increase. Adjusting thrust on the fly by changing the Q limit number in MechJeb is finicky. I'll check if Smart Parts allows a staging event to trigger a change the thrust level. That would neatly deal with the problem.

Yeah I don't know Python. Setting a Thermal limit would also work I think. Like "don't go over x% of the max temperature for the most critical part."

Good morning. I'm seemingly obsessed with Eve ascents. Constantly trying to find the lightest weight vehicle. I don't hand fly. Mostly I use MechJeb. However one of the problems I face is suboptimal thrust control. MechJeb allows setting of a dynamic pressure (Q) limitation on thrust, which is good for the initial ascent. However later I have a feeling that higher thrust is better due to an increase in terminal velocity. I would like to be able to control thrust by matching vessel velocity (EAS) to estimated terminal velocity, both numbers found in Aero GUI from the debug menu. Another option would be thrust to be limited by a specific local Thrust to weight ratio. Say TWR reaches 2.0. At that point thrust stays at 2.0 and does not go higher. Is there any add-on that allows setting thrust to follow various parameters like this? Alternatively, perhaps someone would like to take the challenge on? Kind regards.

Any way to disable GravityTurn without uninstalling it? Sometimes I want to use MechJeb instead but GravityTurn seems to be "interfering".

Fancy.

Aaaaah. New version here.

I understand this still works in 1.3 but I don't get the Gravity Turn icon in the toolbar. Any help appreciated. EDIT: Aha! There's a new version! Apoligies for necro-thread.

I don't get the Gravity Turn icon in the toolbar... I tried removing all other mods but no joy.

I did some comparison tests on closed intakes vs straight cones vs slanted cones. Intakes win, just barely, over straight cones, and slanted cones come out last. In any case the difference is quite small; around 2-3%.

Thanks for that. Unfortunately that add-on seems no longer supported. Guess I'll have to do the old trial and error in MechJeb instead.

Cool. That's inspiring thanks. I had a feeling Vector was the way to go somehow... Are those intakes? Any particular reason? Also, why hardpoints instead of decouplers?

Thanks for the ideas. I don't really want to go chair. It doesn't feel "realistic". The fairing is that wide due to the MechJeb box on the side.

Further tweaking got me down to just under 40 tons. I'll have to ponder a lot more to get down to 25 tons.... Tweaked the tankage and replaced the three sparks in the upper stage with a Terrier. It adds 0.2 tons but the vacum ISP goes from 320 to 345, which makes a big difference above 50km. Craft file here.

44 tons from Eve sea level to a 150km orbit. Boo-ya! Pondering apparently helps. It's not 25 tons yet but I'm getting there. I do love the Vector engine but it weighs 4 tons. Replaced the central stack engine with a Spike. Cut tankage all over, added two extra Sparks to the upper stage for a total of three, exchanged the fins for canards (the Spike doesn't gimbal) and my ISP is still higher than before. Not as fast in the first couple thousand meters due to lower TWR, and that is an efficiency loss, but once she hits the max Q wall any excess thrust is wasted weight. Using a Vector at one third to a quarter thrust is a lot of wasted weight. A key aspect seems to be high TWR until you're almost at the circularization burn. And not burning up. Thing get really hot near the top. Craft file for the ascent vehicle here.

Time for some pondering. And testing. And more pondering. And more testing...

Looking at your vehicles, they seem way too wide and short. Given the thickness of the atmosphere, the trick to Eve ascent is a narrow, streamlined profile. Fairings are key. I did some tests and adding the fairing shown below to the middle and upper stages increased first stage performance by over 30%. Also, wide and short vehicles easily become unstable and start tumbling in a thick atmosphere. I had to add a reaction wheel thingy to the middle stage of my vehicle or it would easily tumble while staging (no gimbal on the Aerospike.) Interstage fairings are important if you have gaps. Basically anything that gets rid of gaps and sharp transitions along the stack will be worth the extra weight. Even using the slanted nose cones instead of the centered ones on the side boosters helps. On the mid stage, I used Oscar-B tanks for the side boosters in order to keep the cross-section narrow. Note on fairings: The do add drag to the front, which makes your vehicle want to back flip. A judicious use of fins/canards and gimbal authority will solve this. You must limit Q so you don't just push against massive drag. My rudimentary testing shows that somewhere around 80-100k seems to be the max Q sweet spot for Eve launches. If you set max Q lower, you won't accelerate enough through the lower atmosphere and your second stage will be left without enough oomph to carry on. You need to get your lower stage well up, at least to around 15-18km altitude, and don't turn before 15-18km, and keep the turn very gradual. You shouldn't be horizontal before at least 65-70km. My vehicle has around 8400 delta-V, which is more than enough for a 100km orbit from sea level. However this is only true if you have a streamlined vehicle, good thrust to weight ratios and a good ascent profile. I started by building the ascent vehicle and testing it with HyperEdit. Once I knew it worked, I added the descent vehicle, a "basket" with a heatshield at the bottom. The tops of the "arms" have fins and RCS to keep the thing pointed in the right direction during entry. Once the chutes are out, the heatshield is deflated and jettisoned. After landing, the "arms" are jettisoned, leaving the ascent vehicle on a "launch pad" made of the bottom of the "basket". Ascent vehicle specs below. Craft file is here: Eve descent and ascent vehicle. Lower stage. One central Vector . One FL T-800 and one FL T-200 tank. 6 Dart Aerospikes in asparagus boosters shedding in pairs. Four boosters with one FL T-800 and one FL T-200. Last two boosters one FL T-800. Mid stage. One central Dart Aerospike. One FL T-400 8 Sparks in asparagus boosters shedding in pairs. 5 Oscar-B tanks per booster. Upper stage. One Spark. One FL T-200. Initial climb from Eve. Large fairing to keep airflow smooth around the messy mid stage. Slanted nose cones. Narrow and reasonably smooth cross section: In the VAB. You can see the 8 mid stage boosters under the fairing. Entering the Evemosphere. The fins and RCS on the "arms" keep the right end pointing forwards. The "basket" has two FL T-200 tanks at the bottom for RCS fuel. After landing. "Arms" jettisoned. I had to add little hardpoints to my "platform" to keep it from sliding down hills. Mid stage Two pairs of boosters gone. Two to go. You speak truth. Any extra 100kg of you can leave on the ground will dramatically improve performance. And streamline, streamline, streamline. The extra weight of a fairing will be repaid multiple times in lower drag. 35-40 tons? Colour me impressed. I know it is possible but the best I have managed is about 60 tons for the ascent vehicle. Typically if I add 5-10 tons on top of that performance improves dramatically. The one in the pics is 67 tons at blastoff. I went back and checked an older design I made. 119 tons, but it had less delta-V than this one! That's what you get for using a Mammoth.

Thanks guys. Much obliged.

AHA! That explains it thanks. Shows what happens when you come back to a game after several months.

Good morning. I'm having issues running FAR in 1.3. I get the FAR button in KSP but pressing it does nothing. Apart from that KSP runs fine. Just to be sure, I removed KSP and all the files, followed by a clean install. I then extracted FAR. Same effect. I extracted "all of Ferram", as in including ModuleFlightIntegrator and ModuleManager. However when I have tried newer versions of these two (downloaded separately), KSP crashes during start. The error log says "mono.dll caused an access violation". Any assistance greatly appreciated. Unity Player [version: Unity 5.4.0p4_b15b5ae035b7] mono.dll caused an Access Violation (0xc0000005) in module mono.dll at 0023:100704db. Error occurred at 2017-06-09_144750. D:\Games\SteamLibrary\steamapps\common\Kerbal Space Program\KSP.exe, run by Andreas. 49% memory in use. 0 MB physical memory [0 MB free]. 0 MB paging file [0 MB free]. 0 MB user address space [2616 MB free]. Read from location 00000000 caused an access violation. Specs: - Windows 10 - Asus Maximus VII Gene - CPU: Intel Core i7 4790. 3.6GHz. - RAM: 16GB DDR3 1600MHz. - GPU: Asus GTX770-DC2OC-2GD5. Nvidia GTX770 with 2GB DDR5. - System drive: Intel DC3500 480GB SSD. - Storage drive: HGST 5400rpm 1.5TB 2.5".

After incautiously checking out some KSP news and feeling inspired, it was back in the deep end. I challenged myself to an Eve mission with Ferram Aerospace mod. My constraints Single launch to Eve surface and back to Kerbin orbit. Jeb must plant a flag on the surface. Ferram Aerospace installed, i.e. "realistic" aerodynamic effects in Kerbin and Eve atmospheres. Ferram made things both easier and harder. On the one hand aerodynamic effects are much less forgiving. On the other hand aerodynamic shapes behave as expected. This allowed me to design a vehicle that could enter Eve's atmosphere without any steering inputs, simply relying on natural stability to keep the heatshield in the direction of travel. I designed and tested the whole thing "backwards". First the Eve ascent vehicle. Once that was done I figured out how to get it from Low Eve Orbit to a soft landing at Eve sea level. Finally the easiest part, which was getting everything from the Kerbal Space Center to Low Eve Orbit. The ascent vehicle weighs in at 187 tons and consists of three basic stages, with the lower stage having external boosters with asparagus staging. Lower stage. One Spike and two Vector engines. Three asparagus boosters with one Vector each. Mid stage. Three Spike engines. Three fins placed on i-beams far aft of the engines for aerodynamic stability. Upper stage. One Terrier engine. For Eve descent, the goal was to make the vehicle aerodynamically stable. I first experimented with active fins and RCS at the top of the stack. This worked in the upper atmosphere but below about 40000 meters the vehicle started wobbling and spinning uncontrollably, eventually leading to either heat-induced or aerodynamic breakup. On a hunch I tried re-entry with no steering and it worked. Most of the weight is at the bottom and the aeroshell can withstand some heating on the side as the vehicle returns to center. The three main features of the descent enclosure are: Parachutes on struts which are jettisoned after landing. Inflatable heatshield. A massive aeroshell encasing most of the ascent stage. Kerbin booster and Eve transfer. Brute force approach with nothing very complex. 13 asparagus stacks with Mammoth engine to start and Rhino engines on the last ones. I relied purely on engine power to enter Eve orbit, since aerobraking directly from interplanetary speeds inevitably led to burnup. Even starting from an atmosphere skimming orbit with apoapsis of 91km and a periapsis of 80km, the heat shield went up to 90% of maximum temperature. Full Mission album