Jakalth

Weight balance will be an issue. I see a huge problem when the craft is light on fuel. As you burn fuel, the COM will creep forwards. As it creeps forwards, your ability to maintain control(Pitch mostly) will be greatly decreased. The hidden canards in the front of the craft gives it more tolerance to this, but it might still be too much. The weight issue would not effect its ascent due to the craft being out of most of the aerodynamic effects before it shifts forwards too much. The front vertical stabilizer might help a bit on the ascent, but as Jens Lyn IV said, get rid of it if you can. The vertical stabilizer up front just increases aerodynamic torque. as the craft starts to turn to the right, the front vertical stabilizer will act like a vain and force the nose to turn even more. This can easily turn a slight wobble into a violent spin. Vertical stabilizers should not be any farther forward on an aircraft then it's center of mass. For example, even the winglets of modern commercial and civilian aircraft are slightly behind the center of mass of the craft to prevent inducing aerodynamic rotation, even though they are only for smoothing the airflow over the wing. Drag... The front of the craft does seem to have a slightly higher amount of drag, for its profile, then the tail. Mostly due to that cupola. But, you have the countermeasures to compensate for this. The rear airbrakes. Add an action group that lets you deploy a few of the rear most airbrakes to increase drag on the tail once your inside the atmosphere. This should help counter some of the front end drag. You should be able to retract the brakes once the craft has slowed down a fair amount and the rest of the control surfaces can keep it under control. My suggestion is to try tweeking it in the order above; Weight, front stabilizer, then airbrakes/drag adjustments.

well, it IS actually 2 Goliaths, and they are moved/clipped into place so they still use their original air intakes. Otherwise, that would be a lot of air intakes needing to be clipped into the hull. But yeah, Goliaths line up perfectly with MK:2 fuel tanks. Plus their mounting pylon makes a nice mounting point for the tail fin. It needs 2 because of the sheer mass of the submarine. Also, the link to the craft is just below the picture, it says Download: and is followed by the link, which is the name of the craft.

Yeah, it requires a lot of trial and error, mostly error. If your sub tends to list forward(nose down), you can either remove a tiny bit of ore from an ore tank near the front to bring the nose up, of shift 1 or more are tanks backwards slightly to reduce the weight on the nose. Just takes trying it out, adjusting, then trying again until you get the balance right. If it's the other way, you can shift weight froward or remove a bit from the back.

@StupidAndy I got it to sink by adding enough filled ore containers that the submarine became slightly heavier then the lift(buoyancy) of the fuel tanks. Balancing this weight can be a bit tricky. The trick with the cargo bay works because an opened cargo bay has more lift(buoyancy) then a closed one. Someone on the forums found this trick a couple years ago. A note with this, filled ore containers are a bit unstable so be careful about placement. They tend to explode if they are clipped into each other and then experience any forces directly applied to them, so either completely clip them inside the craft or try not to clip them into each other if they are exposed.

Oh, a few notes on the Marlin that I forgot to mention. 1: Shes a bit faster when fully submerged, like a real submarine, maybe 2m/s. 2: You can manually toggle the front or rear cargo bays to get the Marlin to perform a rapid change in pitch, but it does have a higher chance of causing the buoyancy to glitch, meaning you'll have to use the action group 2 fix to reset it's buoyancy. 3: Breaching the surface can be dangerous, but cool to watch. But, if you want to perform a clean surfacing, either toggle the cargo bays closed about 50m below the surface to slow the ascent before opening them at the surface. Or just use the engines to power its way up and then toggle the cargo bays.

How about a functional stock submarine? The Marlin Class Explorer is currently setup as an exploration submarine with working active ballast(uses the cargo bay trick for changing buoyancy). The craft is capable of diving and surfacing under engine thrust alone, but can also use the cargo bays as ballasts to bring the craft to the surface a bit quicker, and in a more conventional way then pitching up hard. With the 4 ballasts closed, the submarine is negatively buoyant, meaning it will slowly sink to the bottom of the ocean if the engines are running slow and/or your not pitched up slightly. With all 4 ballasts open, the sub is positively buoyant and will sit a little over half way out of the water. With only two open, it sits less then half way out. The submarine only uses 2 action groups by default. Action Group 1: Standard ballasts. Two of the cargo bays are toggled, increasing the buoyancy and causing the submarine to surface at about 6m/s, or a normal climb speed you'd expect for a submarine maneuvering. Action Group 2: Crash Dive!! All 4 cargo bays are toggles, making a more dramatic change to the submarines buoyancy. With all 4 open, the subamrine nearly doubles it's ascent rate and can go completely airborne when reaching the surface. Great for dramatic cinematics, but can be dangerous for the engines, which can't always handle the impact when it smacks back into the water, making a huge slash.(think the US submarine in the movie The Hunt for Red October, when it does the emergency surface and breaches the surface hard) This action group also serves two other purposes. One, it keeps the sub at the surface for when you first enter the water(starts with the cargo bays open just a crack) and initially sets the buoyancy once your at a safe distance from shore, which is about 100m+. Two, it allows you to reset the buoyancy if the game has a physics hickup and the standard ballasts stop working for some reason. How to use: 1: Launch the submarine onto the runway. 2: Get off the runway as soon as possible and roll along the grass beside it, the steep end of the runway will kill the submarine if you stay on it. 3: Watch your speed. It has quite a bit of thrust and can get a bit out of control if you go too fast. 40-50m/s is safe(ish) until you reach about where the runway ends. 4: She's VERY heavy, a mere 476tons, so brake brake brake!! The brakes are set to max but take a while to slow her down, start braking early. 5: Slow her down to a speed of no more then 15m/s when entering the water. Too fast and she will tail slap when entering, possibly destroying her engines. 6: Run the engines to bring her away from shore. You want some depth below you when you toggle the ballasts. 7: Once your at a safe distance, use action group 2 to close all the ballasts and crash dive. This will allow her to submerge and set her buoyancy initially so the submarine operates properly. 8: If at any time the ballasts stop working properly, make sure all 4 cargo bays are closed and use action group 2 to open them, then close them again. This should reset the buoyancy so it works properly again. Shouldn't need to fully surface to do this, but it does make it easier. Her cruise speed is around 14m/s, so she's not a record breaker, just capable. She can pitch up and down pretty well with the 4 canards and turns fairly well with the big tail rudder. Nothing quick, so it feels like a submarine when your driving it around. If you deploy the landing gear, she will sit nicely on the bottom of the sea, waiting until you need her, and it is possible to drive it back onto dry land if you have a need for that. Download: Marlin Class Explorer

Alright. Got one for you guys to try out. This is easily my best turboshaft engine. Works extremely well, and only uses 8 Juno's as blowers. It is very much a lite duty turboshaft atm but I'm sure it's total power could be ramped up immensely just by adding more blowers. The engine it's self is stable, can handle some rough maneuvers now, and no longer freaks out when being tilted. The platform it is mounted to allows the turbine to be flown, and it flies surprisingly well. The craft is almost stable enough to be flown without using sas. Still has a slight torque indifference though. This craft is just a flying test bed for the turboshaft engine. Meduim turbine 1 aka: flying twin rotor testbed. Staging is setup, but ejecting the stack separator to free the turbine is a bit glitchy. Make sure the separator is completely free of the turbine housing before staging to the engines. The separator tends to not cooperate and likes to wedge its self inside the turbine housing. If this happens, simple retract the landing gear and let the turbine drop to the ground. Once the separator is free, extend the landing gear to pick the turbine back up again. The turbine is close enough to the ground for this to work. Second stage simply starts the engines and releases the docking clamps, whos job is simply to prevent the whole craft from being launched by the glitchy separator. Also, the controls are a bit odd. w/s pitches up/down, a/d rolls left/right, and q/e turns right/left. This is due to the oddly placed drone core. But don't worry, this craft can be recovered from odd angles fairly easily. As a last note, this craft has no fuel so requires infinite propellant. Once this turboshaft design is perfected with better bearings, better rotors, and better/more blowers, it should have more then enough power to lift the fuel it needs.

Well, I did figure out most of the issues with the second helicopter. They involved not using the Completely broken and useless small steerable landing gear and replacing them with the much larger small stow able landing gear. Not ideal due to size difference, but made the turbine stable enough for flight. Not it's simply a matter of me not being very good at making helicopters... :\ But on a different note: I've done some testing and got a heavy turboshaft working. One that's capable of lifting a 60 ton craft into the air. Sadly the design is only usable if you don't make any kind of maneuvers other then just flying strait up... Any maneuvers at all and it spontaneously disassembles... But I do have one success, even if it's not complete, I have a working duel output turboshaft. This turboshaft can spin a set of rotors on both ends of the engine, not just the one end. It seems to handle some pretty high rpm's as well. Don't have VOID installed, and keep forgetting to install it, so don't have exact numbers. But testing shows it's more then capable of lifting its own weight, and then some, with only basic 6x symmetry rotors. I'm not sure yet what advantages this setup might have, but so far it doesn't seem to have as much of an issue with the rotation of the rotors causing the craft to tip to one side. Of course, being one of my designs, it's not entirely stable yet and the turbine tends to pull it's self free from the bearings when subjected to lateral forces. aka: tilting

Ok, that would be a simple choice for me. My best aircraft is the Delta Kite. The reasons are simple. 1: It has a clean design that turned out better then I had hoped. 2: It's fairly maneuverable. 3: It flies stable from full tanks all the way to empty. 4: It has extreme endurance. With full tanks, it can stay airborne for up to 12 hours and circumnavigate the planet with fuel to spare. 5: It's quite relaxing to fly and gives you time to think.

Hay Azimech, it's been a long time since I chatted here. Finally got back into trying to make vanilla turboshaft engines and fell into the now common problem of landing gear being a P.I.T.A.... So I did end up finally getting one turboshaft to work, all be it very inefficiently... It has a hybred half landing gear half slide bearing design. thought you might enjoy the novelty of looking at it. 1.3 copter test3 Barely flies, terribly inefficient and underpowered, but the turboshaft engine it's self seems somewhat solid...ish... 30 Junos as blowers. The main reason I'm asking here is for some tips on the second turboshaft I'm working on. It's part of a partially completed heli, which will be redone once the turboshaft engine is bug fixed. The engine it's self has far more power then the other one and is lighter. But it has a fatal flaw... The top landing gear bearings... The engine spins up nicely and has enough torque to spin the rotors at a good clip. But when it gets close to full power, the shaft of the engine starts to hop and will eventually bounce with enough force to destroy the bearing wheels on the bottom of the engine. This becomes a fatal problem quickly. I can't quite find a solution to this bounciness problem, and I have tried several different tricks to reduce the landing gears recoil with no success. The engine is stable enough laterally, but it's the vertical glitchiness that kills it... prototype turboshaft heli 1 The heli's body is temporary, I'll be making it look and work better once I can find a solution to the engine. Got a prototype heavy turboshaft engine atm that weights in at a heavy 24.185 tons empty and is capable of lifting off with a 3/4 filled S3-7200 fuel tank, with 4 wheasleys for counter torque, weighing in at 32.6 tons, for a combined weight of 56.785tons. Is that good, bad, average???? It's using a 6x symmetry rotor make from 5 "wing connector type E", and this one does not have the maniac shaking of the above model... Uses 40 Junos as blowers. Also, still looking for any tips I can get on how to stabilize a more compact turboshaft engine. Trying to use the small stearable landing gear but getting a lot of rebound glitching which eventually leads to violent dissasembly.

Na, mostly popcorn and baby tears...

Yeah, that name was stuck somewhere in my head, couldn't quite find it...

fair enough. But the challange is still building a turboprop that can actually move an aircraft with a lot of fuel on board. If someone can pull that off though. It would be impressive. I intend to give this a try. Hopefully, if I can find the time for it now that my vacation is over...

He's talking glitch drives, infiniglide(ish), and other bugs that can be used as a form of propulsion for those crazy(or just plain skilled) enough to try harnessing them.

That may be true if it wasn't for the fact that this is a Turboprop challenge, which means jet engine blowers. Although that might need to be specified in the rules, or have a separate class for the electric types?