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Post by alias72 on Jan 20, 2017 19:37:45 GMT
Hello. I am designing A KKV and have run into a few problems. The KKV has 4 thrusters mounted radially. The KKV Always attempts to orient itself sideways assuming itself to be a conventional rocket. This is unfortunate as it wastes DV on a gimballing maneuver or, worse, thrusts in all directions at once providing no net acceleration. Is there any way to force the targeting computer to rely on planar translations and simply attempt a constant bearing decreasing range intercept? Another issue that I know has no solution is that radial thrusters cannot be made deploy-able so they are never flush with the side of the ship. But this merely effects coil-gun bore radius.    EDIT: I designed another (Symmetrical) KKV and it thrusted continuously in all directions. It did not hit its target. It is likely that the targeting computer does not know how to handle the ship. This is unfortunate as guided munitions such as this vastly increase the effective range of kinetic weapons. my new design fires a 25kg penetrator (30kg shot) at 1.5 km/s with 200m/s dv for an effective range of: Opponent thrust (mG) 300: 102km 500: 61.2km 800: 38.3km I also tried having thrusters fore and aft. The result was the same. The AI does not appear to know how to use anything other than a gimbal to turn. This is unfortunate as Gimbals are a terribly constrained means of changing orientation in space. |
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Post by argonbalt on Jan 20, 2017 19:38:45 GMT
post pics
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Post by bdcarrillo on Jan 20, 2017 21:11:17 GMT
Unique idea...
If they aren't exactly at the CG, they'll cause some odd torque. As you expend fuel your CG will change, making it kinda tough.
Maybe try a test rig with a ring of thrusters fore and aft of the CG and see if it orients properly
I would switch to a monoprop and have your tank at the center, engine and remote at the rear and tweak the warhead to balance the engine and remote. Then pop your ring of engines in the middle of the tank.
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Post by alias72 on Jan 20, 2017 21:39:49 GMT
Unique idea... If they aren't exactly at the CG, they'll cause some odd torque. As you expend fuel your CG will change, making it kinda tough. Maybe try a test rig with a ring of thrusters fore and aft of the CG and see if it orients properly I would switch to a monoprop and have your tank at the center, engine and remote at the rear and tweak the warhead to balance the engine and remote. Then pop your ring of engines in the middle of the tank. The rockets are at the CG but to prevent the odd torque I gave them a gimbal range of 3.3 degrees. In real life I would jacket the tungsten rod with the fuel tank to prevent oddities. I might try that test rig idea. My initial idea involved a hydrogen peroxide monoprop but I dropped this for a few reasons. 1) the DV I achieved was only 69 m/s. This gives me an effective range of 300mG: 42.5 KM 800mG: 15.9 Km I concluded that I would need 200 m/s for a viable rocket 2) little need. The autoignition temperature of hydrogen peroxide with RP1 is 493k which can be achieved by the decomposition of the Hydrogen peroxide. The result is a semi-hypergolic propellant. Additionally H202 has fairly good soluability. I suspect that it can be dissolved in the RP1 to create a monoprop mixture (though I have been unable to find research on this). 3) currently all the weirdness in positioning comes from the limits of the design engine. Otherwise the rockets woul be dead center with the tanks. 4) I am ripping this idea from a game called attack vector tactical. So the originality isn't just my own. That said AV:T has a different way of handling missiles that I am trying to understand. Might make a thread on it. |
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Post by Easy on Jan 20, 2017 21:57:00 GMT
Does removing the gimbals improve or worsen performance?
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Post by alias72 on Jan 20, 2017 22:05:33 GMT
Does removing the gimbals improve or worsen performance? Improve slightly. The Rockets pulse instead of burn continuously. The still consistently fail to adjust position. I need to do a full redesign to test whether this is a CoG issue. My past attempts have all ended in projectiles trying to orient sideways. EDIT: Not a CoG issue. |
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Post by bdcarrillo on Jan 21, 2017 4:00:29 GMT
I threw together a monoprop prototype and put the nozzles dead center on the CG. Similar accel/dv specs, about half the weight overall.
By pausing and unpausing vigorously I noticed that the engines engaged only on terminal, but ALL of them appeared to fire, resulting in essentially no change to trajectory.
Control was set to augmented proportional, no acceleration at all.
May need to force an engagement further than 30km or so and load in more fuel.
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elukka
Junior Member
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Post by elukka on Jan 28, 2017 13:49:51 GMT
I haven't been able to make any design based on RCS thrusters work very well. They just burn their thrusters continuously or erratically and oscillate all over the place. If it worked, a vehicle like what you have there would be excellent for missile defense. Essentially, you'd have these: www.youtube.com/watch?v=KBMU6l6GsdMLaunch them using a gun or a small rocket. They'd only need enough speed to get some safe distance away from the ship, the incoming missile's speed would do the rest. Because it needs much less delta-v than the missile (it only needs to get in its way, and the missile can't divert much without missing your ship) you could carry many of these for the mass of each missile. I suspect it would rather shake up the meta. The default ships which use RCS thrusters sort of work sometimes but even they're very wasteful at it and not very good at turning. I hope for better control systems for this stuff in the future. |
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