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0toShifty posted:If you lost an engine on takeoff, you'd spin like a top! So, built in auto-rotate. Sounds like a safety feature to me.
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Mar 13, 2018 15:34
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drunkill posted:737-20 shorthaul Airbus will not be beaten in this lucrative new market 
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Mar 13, 2018 17:04
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Sagebrush posted:Airbus will not be beaten in this lucrative new market Why did you just post a photo of the A318? It's meant to be photoshops! 
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Mar 13, 2018 17:24
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https://i.imgur.com/5s4XzSB.gifv
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Mar 13, 2018 20:55
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Party Plane Jones posted:(a big quoted gif) Hey that looks Ola fucked around with this message at 21:07 on Mar 13, 2018 |
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Mar 13, 2018 21:04
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drunkill posted:737-20 shorthaul Can I tell you how loving deeply disappointed I was when I found out this was not a real thing? Cause it's loving adorable.
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Mar 13, 2018 21:30
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drunkill posted:737-20 shorthaul Clinton Deploys Very Special Forces To Iraq 
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Mar 13, 2018 21:57
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Finally a multirotor design that might not kill everyone on board if it loses power.
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Mar 13, 2018 22:42
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New Kerbal Space Program DLC looking good.
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Mar 13, 2018 22:46
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MohawkSatan posted:Can I tell you how loving deeply disappointed I was when I found out this was not a real thing? Cause it's loving adorable. 
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Mar 13, 2018 22:55
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um excuse me posted:Finally a multirotor design that might not kill everyone on board if it loses power.
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Mar 14, 2018 00:35
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evil_bunnY posted:If you lose power in the helicopter regime good loving luck. Helicopters aren't particularly safe in that regime either.
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Mar 14, 2018 00:54
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Well theory-wise a conventional helicopter gets to retain directional control authority and some energy to arrest the descent even in a non-ideal autorotation scenario, with skids/shocks/stroking seats helping out at the bottom. In practice, plotting a low-inertia rotor system aircraft in a high DA scenario for the small amount of time it spends in the "you're hosed" flight regime against the likelihood of this thing losing more than one micro-motor (massive battery failure?), well I dunno which comes out statistically safer but I'd rather crash the one with big rear end shocks. I wonder if an aircraft like this could dismount all the quadcopter bullshit and just be an airplane for those places where VTOL is unavailable or unnecessary?
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Mar 14, 2018 01:49
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It looks like they added all the mutirotor crap on after designing a really nice looking conventional aircraft.
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Mar 14, 2018 02:01
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If you have enough small rotors, theoretically I think it would be possible for the control system to sense a failure in any single rotor and compensate with the deactivation of other rotors, providing degraded performance but possibly a survivable crash landing. In a quadcopter, that wouldn't be possible, but we're talking 12 rotors here. 10 rotors could probably still arrest the sink rate and maintain control enough to permit a hard but survivable landing.
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Mar 14, 2018 02:13
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Hybrid designs like that are a waste. They have lots of extra complexity and weight that is mostly going to go unused. Tiltrotor is basically the way to go if you need VTOL and fixed wings without melting the ground.
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Mar 14, 2018 02:23
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PT6A posted:10 rotors could probably still arrest the sink rate and maintain control enough to permit a hard but survivable landing. What if we put some sort of fixed airfoil sticking out of each side of the vehicle? How many rotors would we need then? e: How much could the L/D ratio on that aircraft be improved if you didn't have the rotors all over the wings? Double, perhaps?
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Mar 14, 2018 02:26
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I think the ideal solution is to gain enough altitude quick enough that if you lose your lifting power, you've got enough room to glide. Or explode in an awesome fireball.
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Mar 14, 2018 02:39
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Finger Prince posted:I think the ideal solution is to gain enough altitude quick enough that if you lose your lifting power, you've got enough room to glide. Or explode in an awesome fireball. So we’re back to the rocket launched F-104. Again.
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Mar 14, 2018 03:00
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What if we put the rotors inside the wings? https://www.youtube.com/watch?v=-aBOmBzcgPE
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Mar 14, 2018 03:01
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Sagebrush posted:What if we put some sort of fixed airfoil sticking out of each side of the vehicle? How many rotors would we need then? Could one build an auto gyro with a zillion mini rotors?
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Mar 14, 2018 03:02
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Did anyone ever put JATO rockets on a dirigible?
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Mar 14, 2018 03:08
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Finger Prince posted:Did anyone ever put JATO rockets on a dirigible? brb booting up KSP
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Mar 14, 2018 03:18
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Finger Prince posted:Did anyone ever put JATO rockets on a dirigible? Just thinking about this makes me semi rigid.
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Mar 14, 2018 03:19
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Seems like it'd make a lot of dirigibles semi rigid too
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Mar 14, 2018 03:39
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FrozenVent posted:So we’re back to the rocket launched F-104. Again. Finally.
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Mar 14, 2018 03:41
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Finger Prince posted:I think the ideal solution is to gain enough altitude quick enough that if you lose your lifting power, you've got enough room to glide. Or explode in an awesome fireball. Yea but at low/no airspeed your only control authority comes from varying thrust on the multi rotors. Assuming they need to maintain balance, a failure of one means at least one other one is brought offline, if not three other ones, so you'd need to have enough of a power margin to maintain attitude control with 8 of 12 fans blowing. A multi rotor is super susceptible to unrecoverable rolling in an unbalanced thrust situation, and I wonder how these engineers have characterized the system's ability to cope with an upward-inflow-like scenario given its unusual shape. I'm guessing this thing is next level sensitive to high rates of vertical descent in hover mode. Not necessarily insurmountable; if that pusher is electric, maybe a computer-fast reaction could achieve a forward descent profile at, say, a 100 foot hover, which could possibly get you moving fast enough to flare if not fly away. This also makes me realize I have no idea how to characterize ground effect for a multi-rotor fixed wing.
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Mar 14, 2018 03:54
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Ambihelical Hexnut posted:Yea but at low/no airspeed your only control authority comes from varying thrust on the multi rotors. Assuming they need to maintain balance, a failure of one means at least one other one is brought offline, if not three other ones, so you'd need to have enough of a power margin to maintain attitude control with 8 of 12 fans blowing. A multi rotor is super susceptible to unrecoverable rolling in an unbalanced thrust situation, and I wonder how these engineers have characterized the system's ability to cope with an upward-inflow-like scenario given its unusual shape. I'm guessing this thing is next level sensitive to high rates of vertical descent in hover mode. Not necessarily insurmountable; if that pusher is electric, maybe a computer-fast reaction could achieve a forward descent profile at, say, a 100 foot hover, which could possibly get you moving fast enough to flare if not fly away. This also makes me realize I have no idea how to characterize ground effect for a multi-rotor fixed wing. Rockets, my friend, rockets. Or a rapid deploy balloon, filled with hot gas from, you guessed it, rockets.
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Mar 14, 2018 11:42
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PT6A posted:If you have enough small rotors, theoretically I think it would be possible for the control system to sense a failure in any single rotor and compensate with the deactivation of other rotors, providing degraded performance but possibly a survivable crash landing. In a quadcopter, that wouldn't be possible, but we're talking 12 rotors here. 10 rotors could probably still arrest the sink rate and maintain control enough to permit a hard but survivable landing.
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Mar 14, 2018 12:35
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evil_bunnY posted:Oh yeah any 6+ multi can do that. I thought we were talking about a power system failure, not a power train issue. Hmm, yeah, I didn't consider that.
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Mar 14, 2018 13:17
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If you have enough rotors, you don't need a main rotor in the middle, which means you can suspend a parachute from it. That's why I think something like a Volocopter is good: It can (in theory) handle a failure of some number of individual rotors by computer, but it obviously shouldn't do that in the Airbus way of hiding the failure behind a compensating computer which suddenly runs out of leverage. It should warn to land asap and limit input if needed, like you can't yaw left because the thrust differential needed to yaw left is now busy maintaining level flight. It needs to display this and the pilot needs to be trained on how to deal with it. If the power source fails completely you free fall, but if you have room for a ballistic chute, you at least have a way out. It's simpler than autorotating and will have a coffin corner similar to the ones helicopters have, where you can be too low and slow for the parachute to unfold but high enough to die.
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Mar 14, 2018 14:03
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Ola posted:If you have enough rotors, you don't need a main rotor in the middle, which means you can suspend a parachute from it. That's why I think something like a Volocopter is good: I don't know as it's simpler than autorotation. A ballistic chute mounted in the middle of your propulsion, exposed to weather and vibration... You *really* don't want it to go off when it's not supposed to, because the consequence would be death, and yet you *really*want to make sure it will go off in the exact specific scenarios that it should (and you're relying on engineers to predict those scenarios accurately). It's overly complex. Autorotation is as simple mechanically as engine braking in a car or bike, to use a not entirely correct analogy.
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Mar 14, 2018 14:27
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Ola posted:If the power source fails completely you free fall, but if you have room for a ballistic chute, you at least have a way out. It's simpler than autorotating and will have a coffin corner similar to the ones helicopters have, where you can be too low and slow for the parachute to unfold but high enough to die. Rockets Zero/Zero ejection system rockets scaled up for the entire craft kind of Rockets 
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Mar 14, 2018 14:39
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Finger Prince posted:I don't know as it's simpler than autorotation. A ballistic chute mounted in the middle of your propulsion, exposed to weather and vibration... You *really* don't want it to go off when it's not supposed to, because the consequence would be death, and yet you *really*want to make sure it will go off in the exact specific scenarios that it should (and you're relying on engineers to predict those scenarios accurately). It's overly complex. Autorotation is as simple mechanically as engine braking in a car or bike, to use a not entirely correct analogy. Going off when it's not supposed to doesn't mean death, it just means a surprise G-load and an aborted flight. They've been in use for many years now on fixed wings (which vibrate a lot more than the Volocopter) and they do work pretty reliably. It's encased in a shell and deploys with a rocket motor (replaced on maintenance intervals), you could easily mount it below the rotor planes to make sure it isn't impacted by a dropped blade or similar. And I think it's definitely simpler than autorotation, you just pull a lever and become a passenger. Autorotating requires well maintained flying skills.
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Mar 14, 2018 14:39
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ThisIsJohnWayne posted:Rockets I’ve got a weird/bad/horny feeling about this your post was BUILT for my username
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Mar 14, 2018 14:44
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From what I can tell on google a BRS parachute system for a Cessna whatever weighs about 85lbs, will carry 3000lbs of airplane, and requires 260 feet of altitude for inflation. That last point might make the utility for hover recovery not super great, which means you really need to rely on the remaining props to arrest descent. Or use a series of small rocket burns on the underside. Or if this is going to remain a useless single pilot thing, just install a zero zero ejection seat and continue to discriminate against ample gentlemen like all small planes. 
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Mar 14, 2018 15:54
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Ola posted:Going off when it's not supposed to doesn't mean death, it just means a surprise G-load and an aborted flight. They've been in use for many years now on fixed wings (which vibrate a lot more than the Volocopter) and they do work pretty reliably. It's encased in a shell and deploys with a rocket motor (replaced on maintenance intervals), you could easily mount it below the rotor planes to make sure it isn't impacted by a dropped blade or similar. And I think it's definitely simpler than autorotation, you just pull a lever and become a passenger. Autorotating requires well maintained flying skills. If one of those chutes deploys on a fixed wing a/c when it isn't supposed to, it maybe gets tangled in the empenage when you cut it free, which would suck, but you can still fly. If one goes off on that multirotor, let's say when it's climbing, it's going to get tangled in half if not more of your propulsion rotors, and then you're hosed.
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Mar 14, 2018 15:58
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Looking at Wikipedia though, a Bell 204B would need at least 800ft of height to successfully auto-rotate at a hover. It looks like it would have to be traveling at about 40 knots to successfully auto-rotate at 250ft.
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Mar 14, 2018 15:59
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Really the answer is to never operate in that regime and use the little rotor blades to enhance STOL capability.
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Mar 14, 2018 16:10
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Finger Prince posted:If one of those chutes deploys on a fixed wing a/c when it isn't supposed to, it maybe gets tangled in the empenage when you cut it free, which would suck, but you can still fly. If one goes off on that multirotor, let's say when it's climbing, it's going to get tangled in half if not more of your propulsion rotors, and then you're hosed. So you have an explosive bolt or spring-loaded anvil or something like that integrated into the parachute rocket motor, and it chops the main power line to the flight motors when the parachute deploys.
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Mar 14, 2018 16:35
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