U.S. Air Force Evaluating Pivotal's Blackfly Ultralight EVTOL Aircraft | Hacker News Reader

U.S. Air Force Evaluating Pivotal's Blackfly Ultralight EVTOL Aircraft

futureflight.aero

134 pointsrbanffy57 comments

From the POV of someone adjacent to defense stuff, the DoD has been in a bit of a tech-curious analysis cycle. They're probably not interested in putting guns on this thing as currently outfitted, but rather they want to see if this novel approach has any potential applications worth further developing. It's not a particularly capable system, but the USAF and USN are currently looking at a whole slew of VTOL systems and this one is both much simpler and much cheaper than any of them. If an arrangement like this is fielded it's probably not as a human rated system but as a large forward deployed combat or logistics drone.

> They're probably not interested in putting guns on this thing

Battles are won with guns; wars with logistics.

Putting ~500lbs of explosives in it might be cool, it would probably be more aerodynamically stable at speed than those fpv quad copters and the vertical takeoff capability and increased range compared to a quad slinging a mortar round seem interesting.. though something engineered for that specific purpose rather than to carry a human occupant would probably be more fit.

>500lbs of explosives in it might be cool

And at $200k a pop it's practically disposable!

GMLRS (w/ 200lb warhead) is $189,000 and falling. https://www.defensenews.com/land/2023/03/27/did-ukraine-fund...

GLSDB is $168,000 with 205lb warhead

A single AIM-9 sidewinder costs $400-500,000. And if you remember, they just shot a hobbiest balloon with one last year, and missed.

$200,000 retail for an evtol seems like a good deal.

I think there is a place for close air support drone between small drones and attack helicopter and fighters. VTOL means that it can operate close to the troops.

500 lbs means that it can carry rockets (which are now guided), small missiles like Hellfire, and small bombs like SDB.

The smaller size, maneuverability, and stand-off range should make it less vulnerable to MANPADs.

They're doing some sort of voodoo for this to be part 103. It's significantly overweight, so they classified it as amphibious. Yet there's no demonstration of those capabilities. Even so, they must be pretty generous with their safety equipment weight exclusions as it's still damn heavy.

It would be nice if they would allow electric part 103 to use a credit of the max fuel load of a gas powered 103 to offset battery weight. I have no idea if that's involved here. But I do see a discrepancy that empty vs gross weight is about a 250 lb difference but they state a max pilot weight of 200 lb.

My guess is they are leaning heavily on the fact that it’s “amphibious” and can count a large portion of the hull weight as a pontoon essentially.

No voodoo there. Refer to FAA's Advisory Circular, AC-103.7: https://www.faa.gov/documentLibrary/media/Advisory_Circular/...

Ultralight base allowable empty weight: 254 lbs Allowance for wing outrigger floats 10lbs x 4(?) 40 lbs* Allowance for whole aircraft parachute 24 lbs Allowance for amphibious fuselage 30 lbs x 1 30 lbs Allowable empty weight 348 lbs

The way its written, looks like they could take up to 120 lbs for floats, but only needed 10 to make the cutoff.

Part 103 makes no discrimination about operator mass. It only specs empty weight with an allowance for fuel. To your point, battery technology gets no credit.

They posted a video on linkedin showing waterborne take offs and landings (see it about 45s into the video). https://www.linkedin.com/feed/update/urn:li:activity:7165474...

Interesting, I wasn't able to find that video on their site or YouTube. I did see that the water landing capability is advertised as being for emergencies only on their site. Perhaps that's why it's not prominent. Definitely bending the rules (not necessarily a bad thing in this case) if the manufacturer says not to use it as amphibious and the regulations require it to be capable of repeated takeoffs and landings from water. Technically the FAA can ask you to demonstrate the amphibious capabilities. What do you say to them, I'm not allowed to per the manufacturer?

"Part 103 makes no discrimination about operator mass."

My point wasn't about part 103 but about a discrepancy in their advertised numbers. Looks like there are a bunch of different numbers out there since it was still experimental. It seems the website officially lists 348 lbs empty weight and 220 lbs pilot max weight.

348 lbs is the max you listed, and the empty weight listed on their site. They are right at the limit.

Do you mean “the FAA can ask me, as a regular plane operator, who has nothing to do with the manufacturer, to demonstrate capabilities of the plane”? Can some FAA guy come to me if I am an amateur pilot, and ask me to demonstrate that my plane is capable of aerobatics, just because it is able to by registration?

"the FAA can ask me, as a regular plane operator, who has nothing to do with the manufacturer, to demonstrate capabilities of the plane”?

If you make any sort of modification or repair to it they could technically recertify it and ask you to demonstrate the required capabilities. This is highly unlikely, but that's why I'm stating that it's technically possible.

"Can some FAA guy come to me if I am an amateur pilot, and ask me to demonstrate that my plane is capable of aerobatics, just because it is able to by registration?"

Is it required to by registration? If it is required and if the plane needed to be certified or recertified, then yes, the plane would need to demonstrate that capability (you could hire a pilot if you don't have the training).

> Shortly after Pivotal officially launched sales of its single-seat personal aerial vehicle—a recreational eVTOL aircraft that requires no license to fly—the company’s “tilt-aircraft” architecture has garnered some attention from the U.S. Air Force. ... Recreational pilots (licensed or not) can order the Pivotal Helix aircraft online at a starting price of $190,000. Because the aircraft complies with the FAA’s Part 103 rules for ultralight aircraft, operators do not need a pilot’s license to legally fly it

I was really surprised that was possible, but this seems to describe the regulatory situation: https://en.wikipedia.org/wiki/Ultralight_aircraft_(United_St....

I thought the same being that you have to have a license just to fly a drone in the US, as long as it's non-recreational, of course.

Would anyone here have any pointers to info on man sized EVTOL design and development here?

Consider the problem you're trying to solve first. Generally speaking, your problem would be better served by a type of aircraft (or non-aircraft approach) that already exists.

Some of the earliest experiments in this area were for the US army in the 1950s:

https://en.m.wikipedia.org/wiki/Hiller_VZ-1_Pawnee

https://en.m.wikipedia.org/wiki/De_Lackner_HZ-1_Aerocycle

Hmmm. No expert here but wouldn’t that thing be target practice for a MANPAD in war?

I think it's even vulnerable to small arms fire. It's slow, low altitude, has miniscule range, and is manned, making it a much bigger target than drones.

It doesn't have to be that way though. Look at this like a PoC. Drop the electrics and the batteries in favor of regular motors, drop the pilot in favor of remote control or self-flying, and you have a vehicle that might be great for logistics in heavily mined areas. Mines are something that we've seen a lot in the war in Ukraine, some estimate that with modern technology it will take hundreds of years to demine what the Russians have put down. So having ways to avoid that to an extent could be extremely lucrative.

Electric motors are a pretty important part of this design. The throttle response is much quicker than is possible using gas powered engines.

This allows the craft to self stabilize in a way that isn’t possible without near instantaneous throttle response.

This response is possible with gas motors, but normally requires variable pitch props to respond fast enough which adds a lot of weight and failure points.

We already have fixed wing drones, vtol fixed wing drones, quadcopters, etc that are effectively open source, from off the shelf components, and an order of magnitude cheaper.

I’m very curious what the army thinks this can do that isnt already being done by various YouTubers in their backyard.

For these situations I think a small generator and cutting the battery size is the right move.

Probably won't be that small of a generator. I'm betting this thing pulls tens of kilowatts just hovering.

Would be interesting how small/light you could make a 100kW generator. Turbo a performance motorcycle engine, couple it to a modern neodymium magnet generator? Or go directly to a miniaturized turboshaft turbine?

Agree, this thing would get shredded by small arms. If it's going into combat zones, it will probably be in a drone configuration.

Getting a IR lock might be challenging on a hot day, and it's probably not very big on a radar. Imaging sensors and, hell, sound, would both be useful for targeting.

Hitting anything at altitude and moving with small arms is a waste of ammo almost all the time. You would need big energy (7.62 NATO or above) plus a little mount with a tracking system plus precision servos, all locked down on something that doesn't move much. It's a lot of kit to carry around.

But, regardless, that thing is dead meat. Electric drive drones everywhere today means AA platforms like Gepard/Cheetah, ZSUs, and similar have returned to the battlefield in force.

Those rapid fire cannons . . ok, basically, explosive shells and soft skinned vehicles like this are a terrible combination, due to how detonations affect flexy materials like this.

We saw this in WW2, when the otherwise-incredibly-durable[1] soft-skinned Wellington bombers and Hurricanes started eating cannon shells from new mods of fighters. The brisance of the explosive shells did a tremendous amount of damage, which sucked, because the Wimpy was frickin' awesome, IMO the most successful medium (but kinda heavy) bomber design of the war. Metal-skinned aircraft still got shredded, but the damage was a lot less - like a LOT a lot, it's hard to overstate what it did to the geodetic frame on a Wimpy - and frag didn't go as far.

[1] Wellingtons could eat infinity bullets, as even if they knocked out a strut, it's a geodetic structure - there's thousands more struts to go, and they share the load. Cannon rounds . . ah, sad Wimpy trumpet sounds

>and it's probably not very big on a radar

all those right angles and exposed props make me think otherwise

Depends on the wavelength. Unlike my (deceased) dad, I never studied or worked on radar, but from what I remember, if an object is much smaller than a wavelength then the structure blurs out of focus so it acts basically like a sphere of about the same size.

This is also why some radio telescopes can get away with mesh wire antennas.

Might be useful for evacuating the wounded from the front lines.

This looks like one of the least battle-hardened devices ever developed. That thick watermelon seed shape from the side looks like shooting fish in a barrel.

Reminds me of those old-timey propeller planes, and gyrocopters.

Twenty minutes of flight time is reasonable for a drone with swappable batteries. It seems next to useless for manned flight. In comparison the cheapest airplane, the Cessna 175 Skylark, has a flight endurance of 4.3 hours.

Yikes that's scary. In a Cessna or similar once you get into your reserve (figure ~45min running time) it becomes very urgent to get on the ground asap. And this thing looks like it glides about as well as a brick.

EDIT: worth quoting:

> it can fly at a cruise speed of 55 knots to a range of about 20 miles (32 kilometers) with 20 percent battery reserves left

That's four minutes of "reserve power" lmao. Absolutely not, no thanks.

EDIT: to put this into perspective, if you're flying at 7500ft and you hit your 4min reserve, you would need to fly straight down at over 20mph, and then aggressively slow your descent during the last few seconds in order to not die.

On the bright side, it seems like it can land anywhere and doesn't require a runway.

It sure can land anywhere, and once those batteries die you'll have a very high likelihood estimate of exactly when and where it'll do so ;)

Like a helicopter, but with way less range, payload, and capabilities.

well, and with no alternative to landing w/ power. at least a helicopter can take a glide path.

With no landing gear, it can only land on soft surfaces without damaging itself. The pilot's visibility is compromised during landing making it dangerous to set down near any infrastructure that will kill you.

Neither the Cessna nor many helicopters (autorotation) need power to land. I wouldn't want to get into one of these e-bricks!

Something tells me you're not supposed to fly this thing at 7500ft for a multitude of reasons. The energy needed to get you to that altitude would probably be prohibitive.

They have rather different performance characteristics, each can do things the other cannot. According to Wikipedia Cessna 175 production ceased in 1962; if that is true it's not really a fair comparison.

They might have meant the 172 skyhawk which is what the skylark is based on and is still available.

If you want applesto apples check out the Mosquito helicopter. One person experimental/ultralight helicopter that can basically match this thing for performance

There's an electric version of that under development too. https://evtol.news/composite-fx-xe-volt-mosquito-proof-of-co...

Seems more analogous to a helicopter than a cessna. VTOL makes it a lot easier to actually use this. You don't need to go to an airstrip - as a rich person toy that means its much more readibly available. As a method of transportation that means that opens up a lot of trips - probably primarily commuting - even if you are limited to 32 km range and destinations where you can arrange a clear area to land.

Helicopters can auto-rotate if you lose power, I'd be interested to see what it's like to deadstick land one of these. I guess that's what the whole-aircraft ballistic parachute system is for? IIRC in other airframes if you deploy that it's basically a write off.

the dead sticking result is probably measured by meters below grass

The good news is that, at 343 pounds when empty, they won't need to dig too deep to recover your body.

They have parachutes for airplanes.

edit:

I didn't read the end of the comment that mentioned the whole-airplane system already, apologies.

Right, but if you deploy the parachute you can kiss your airplane goodbye. It's totalled at that point and will never fly again. So in this case that's a $190k decision. Why not instead just fly an airplane (or helicopter) that is good at being an aircraft? If your budget is $190k you have some incredible options available.

I mean, people buy airplanes AND an airplane parachute already - there's a reason for it, even if it just means a bigger chance of personal survival.

Right, but (at least in normal aircraft) an engine-out situation doesn't (usually) immediately mean "pull the chute right now or we'll die". Instead the chute a last resort where the the alternative is unpleasant enough that you're willing to trade your aircraft to avoid it (e.g. you're staring down a situation where the aircraft will be destroyed anyway--think going down in trees, mountain cliffs, buildings, water, ...).

In other words, in a normal aircraft you still have options when you lose power.

Cirrus makes great planes on their own merits, before considering the parachute.

I thought the point of this thing is you don’t need a license to fly it.

I guess it makes a good gift for a rich parent if you want to get that inheritance a little quicker?

Not necessarily? Here's a Youtube video of the parachute system in action. Seems like the aircraft could survive depending on where it lands?

https://www.youtube.com/watch?v=lcsutISR6os

That looks like it was pretty easy on the machine, but they started in hover and used the engines to slow descent at the end. I'd be interested to see what happens when the chute opens at speed, and they don't fire up the engines to dull the final impact.

Autorotation depends on rotor inertia and rotor pitch control.

These companies don't do pitch control because if they could, they'd build a helicopter or an Osprey analog, and fixed pitch rotors must be low inertia to slew thrust quickly.

So no autorotation.

Put Maverick in there. He'll make that work.

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