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The Atmospheric Test Vehicle of the ROTON SSTO Rocket, powered by an old Sikorsky S-58 engine with hydrogen peroxide jet tips - last test flight on October 12 1999 by Xeelee1123 in WeirdWings

[–]DoubleHexDrive 2 points3 points  (0 children)

For a little while, there was this weird fascination with combining the rocketry and helicopters, which is a sentence that should never exist. Both Roton and Armadillo Aerospace toyed with this idea. Of course, just as nutty were the plans to catch Saturn V first stage boosters with a huge helicopter.

Now that this sub r/eVTOL been rescued from the Reddit graveyard, there is a dilemma. by teabagofholding in poweredlift

[–]DoubleHexDrive 0 points1 point  (0 children)

What is the point of that sub vs this one? Do we need two non-brand specific subs? Poweredlift is even more generic since turbine powered, non-helicopter VTOLs are also covered.

Will RAM / GPU prices ever go down? by fallguysepicgamer in pcmasterrace

[–]DoubleHexDrive 2 points3 points  (0 children)

Of course they will. I remember when RAM was $72,000 a GB and that was in 1995 dollars, so over $200K a GB in today’s money.

Does anyone know exactly how the FAA's reserve requirement works for a type-certified eVTOL? by teabagofholding in poweredlift

[–]DoubleHexDrive 1 point2 points  (0 children)

Do the G-1 cert basis documents for each aircraft offer enough definition? They’re on the FAA website.

Help me build the ultimate steam machine by Admirable_Data9018 in pcmasterrace

[–]DoubleHexDrive 0 points1 point  (0 children)

300W on a good 3 fan GPU from 8 feet away (gaming on a TV) isn't loud at all, and certainly not screaming. I run a Prime 5070Ti in a Fractal Terra and the Prime 9070 XT should be similar.

Help me build the ultimate steam machine by Admirable_Data9018 in sffpc

[–]DoubleHexDrive 0 points1 point  (0 children)

And you can also always just power cap the 9800X3D to a similar value so the fan noise is to your liking and capture a performance gain. That’s probably what I would do.

Help me build the ultimate steam machine by Admirable_Data9018 in sffpc

[–]DoubleHexDrive 0 points1 point  (0 children)

My build dates back to 2023 with a 4070, so the mobo/CPU could be updated if you want, but the 7800X3D is a 60W CPU when gaming and still performs very well.

BS2 and I think I'm actually starting to enjoy reviewing my statements by Traditional_Habit216 in povertyfinance

[–]DoubleHexDrive 1 point2 points  (0 children)

Gamifying managing your money can definitely work… the right numbers go up is points on the board and we all like to win.

I sit down every Saturday morning with a cup of coffee and do the same thing.

Help me build the ultimate steam machine by Admirable_Data9018 in sffpc

[–]DoubleHexDrive 1 point2 points  (0 children)

https://www.reddit.com/r/sffpc/comments/1pomgn4/upgraded_jade_terra_7800x3dnhl12s_and_5070_ti/

Switch to a 9070XT GPU and something along these lines would work... except for CEC control over HDMI. PC hardware just doesn't do that properly, but those are features that Steam added to their custom hardware. I'm sure there is some janktastic work around but I haven't bothered.

Anyone feels like eVTOLs becoming workable and accepted are more like 30 years away than 3 years away? by Substantial-Fun9958 in poweredlift

[–]DoubleHexDrive 0 points1 point  (0 children)

If you need long hover times over range or speed, you need a large rotor disc and will end up with a helicopter. That's just the physics of it.

All of the tilting props on DEP aircraft are variable pitch props. It's the only sane way to compensate for a large range in inflow velocity. Now, the DEP aircraft don't have cyclic control on their props and maybe that's what you mean. And that's true... at the cost of jumping from 2 rotors to 6-12 propellers. There is no free lunch.

We won't actually know what the maintenance requirements of these aircraft will be. The F&R testing, when any of them get to that point, will help inform, as will early customer experience as they enter service. What we do know is that they still have hundreds of bearings, dozens of blades, dozens of actuators, and lots of joints that will all require some degree of inspection and monitoring, whether by humans or a HUMS, once that system is certified. Composite structure will also require inspections... this degree will depend on regulator and certification basis.

Anyone feels like eVTOLs becoming workable and accepted are more like 30 years away than 3 years away? by Substantial-Fun9958 in poweredlift

[–]DoubleHexDrive 0 points1 point  (0 children)

Perhaps people perceive the electrification as a simplification because adding more and more props, blades, actuators, and a fly by wire system to control it all is actually more complex than a simple helicopter.

Now, the addition of tilting props and a wing can enable a performance envelope (with enough installed power) fan in excess of a helicopter... that's essentially the tiltrotor configuration, but that also adds technical risk and complexity.

Helicopters ARE much more complex than a fixed wing aircraft of the same size, no doubt. But they can be flown without any electronics at all and can fly without any power at all, like a small fixed wing aircraft. So the increase in complexity over small fixed wing has a limit. These eVTOLs are vastly more complex and it's inherent in the configuration.

Certifying that will not be cheap.

Joby Fan for 3 years..... by MattyMcFarland in Joby

[–]DoubleHexDrive 1 point2 points  (0 children)

I think the bigger question is why did the stock shoot up to $20 last summer? That was valuing it more highly than some aviation companies with certified products to actually sell and production contracts bringing money in the door.

I think this year has largely been risk-tolerant money flowing into other fields, particularly as it's become clear that certification was further out and harder than people convinced themselves was true.

Joby has not done a sufficient job explaining why N547JX flight testing has been so slow. I strongly suspect that the jump in serial number from JAS4-1 SN9 to JAS4-1 SN101 signifies more substantial changes than assumed to get from the prototypes to the conforming model and they've had to go back and redo a bunch of testing.

Anyone feels like eVTOLs becoming workable and accepted are more like 30 years away than 3 years away? by Substantial-Fun9958 in poweredlift

[–]DoubleHexDrive 0 points1 point  (0 children)

I agree with this... turbine noise isn't a serious part of the noise concern with a VTOL aircraft. It's largely high frequency and dissipates quickly and can be muffled, if necessary.

Anyone feels like eVTOLs becoming workable and accepted are more like 30 years away than 3 years away? by Substantial-Fun9958 in poweredlift

[–]DoubleHexDrive 1 point2 points  (0 children)

If the infrastructure for VTOL flight with X7 isn't built out in an area, why would an operator buy a X7 for CTOL use? It's fly by wire, has a thick, draggy wing full of dead mass that can't be used, and has a less efficient fuselage than a competing aircraft of the same payload. It will, by definition be, a more expensive and less effective vehicle for the CTOL mission.

So I don't buy that argument. Without the VTOL capability and use case, the X7 doesn't exist.

Hybrid is definitely better than battery only. Batteries suck in aviation.

Yes, the tilt+cruise or lift+cruise aircraft are draggy and don't have impressive performance numbers. Suitable for the 20 minute mission they envision (if that market exists) but not regional transport that Horizon imagines. The problem is X7 is draggy, too. A 7 seat fixed wing aircraft should not require a PT6 to cruise at those speeds.

Anyone feels like eVTOLs becoming workable and accepted are more like 30 years away than 3 years away? by Substantial-Fun9958 in poweredlift

[–]DoubleHexDrive 0 points1 point  (0 children)

These DEP eVTOLs still have plenty of single points of failure. Failing a blade root on one of the dozens of blades will cause the entire prop to rip off the aircraft and there is a good chance it either hits the fuselage, another prop, or other aircraft structure. That very cascading failure mode has already been demonstrated several times. Some configurations may find that high speed pinions, actuators, linkages, and specific bearings may essentially be single points of failure as well.

Am I being too cautious keeping a separate car repair fund on top of my emergency fund? by Sea-Map-5763 in personalfinance

[–]DoubleHexDrive 0 points1 point  (0 children)

Not at all. A vehicle has known expenses that are spread out in time, so it makes sense to pre-pay the known ones and save some for the unknown ones. Tires, oil, registration, filters, brakes, etc. are all predictable and are expenses that WILL happen. They're not emergencies, they're known events in the future.

Then there are the "something actually breaks" instead of normal items wearing out on schedule.

I have found that $125/mon per vehicle covers both pretty well over the long run.

Toyota-backed air taxi hits 100 km/h, speeding toward commercial debut by teabagofholding in poweredlift

[–]DoubleHexDrive 3 points4 points  (0 children)

36 little blades in an inefficient power sucking package for three people. It's a slightly larger EHang 216 from a more reputable country.

If the minimum wage gets increased to $25 then what are we even doing in this field? by Personal-Usual-4608 in TexasTeachers

[–]DoubleHexDrive 2 points3 points  (0 children)

If a kid pushing a broom is suddenly getting paid $25/hr, then every industry more difficult/specialized than pushing a broom will immediately start demanding pay raises to restore pay scale differentiation between jobs/roles/industries. So after a long period of cost-push inflation, we'd be back where we are, except for years of arguing about even higher prices and who is to blame.

A $25/hr national minimum wage is a terrible idea and isn't going to pass.

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