Is this website about hypersonics legitimate ? (EDIT: It's absolute fiction)

[Selective Genius]

6 hours ago, sevenperforce said:

Translating orbital speed into ground speed is just the best.

I am willing to overlook the 'orbital velocity = ground speed' goof up if that guy could explain to me what magic fuel he is using in those little forward thrusters that could decrease orbital velocity by 5000 miles per hour (2.2 km/s) with such a little tank. In his diagrams, the little tank in the nose section is approximately 6 ft long and 3-4 feet across. If that small tank+engine could change orbital speeds of a 225,000 lbs vehicle by 2 kilometers per second, wont it make much more sense to use that to get into orbit at the first place?

And WHY would he need the forward thrusters anyways? Can't he just turn around retrograde and fire up his aerospike engine to decelerate? Or use a conventional hypergolic OMS.

3 hours ago, FleshJeb said:

I kind of want to hit up the Contact page, pretending to be one of:

• An enthusiastic venture capitalist
• Retired Air Force General-turned-defense industry "consultant"
• A particularly venal congresscritter

Or someone from Fox News who wants to invite the guy over to the Tucker Carlson Tonight to discuss "Why NASA is funding SpaceX to blow up water tanks on taxpayer's money."

Or as the evil supervillain Herman VonKerman "With your intellect and my resources, we will rule ZA WORLD!"

Or as a Nigerian crown prince who was ridiculed by his Iranian friends for not having a launch vehicle.

[DDE]

12 hours ago, sevenperforce said:

Yes, it DEFINITELY sounds like a good idea. Ground troops! How would you like to fire a Mach 10 scramjet from this tripod?

It's less far-fetched than you think. I've seen the Russian Hermes being plugged as a Mach 5 tactical missile with 100 km range. AFAIK it's just the AA missile from Pantsir. 

3 hours ago, Selective Genius said:

And WHY would he need the forward thrusters anyways? Can't he just turn around retrograde and fire up his aerospike engine to decelerate? Or use a conventional hypergolic OMS.

That would require him to have the extensive expertise of a KSP player.

[K^2]

4 hours ago, Selective Genius said:

And WHY would he need the forward thrusters anyways? Can't he just turn around retrograde and fire up his aerospike engine to decelerate?

A plane cannot fly backwards. Everyone knows that! 

[kerbiloid]

2 hours ago, DDE said:

That would require him to have the extensive expertise of a KSP player.

Or a spherical plane.

[sh1pman]

I have a brilliant idea to improve these designs. Fuel tanks should be removed completely to reduce drag. 

[sevenperforce]

8 minutes ago, sh1pman said:

I have a brilliant idea to improve these designs. Fuel tanks should be removed completely to reduce drag. 

Leaving much more volume! For extra thrust!

4 hours ago, K^2 said:

A plane cannot fly backwards. Everyone knows that! 

It clearly needs its wings for very height!

8 hours ago, Selective Genius said:

what magic fuel he is using in those little forward thrusters that could decrease orbital velocity by 5000 miles per hour (2.2 km/s) with such a little tank. In his diagrams, the little tank in the nose section is approximately 6 ft long and 3-4 feet across. If that small tank+engine could change orbital speeds of a 225,000 lbs vehicle by 2 kilometers per second, wont it make much more sense to use that to get into orbit at the first place?

He says the Discovery SSTO contains 8,000 gallons of "hydrazine or similar" which comes to what -- 32 tonnes of hydrazine? Let's give him the benefit of the doubt and say it's a 200,000-pound vehicle (about 91 tonnes) empty. The best hydrazine thrusters can provide about 240 s of specific impulse. That's 710 m/s of dV....which, admittedly, is enough for a deorbit burn, but it's not anywhere near 2 km/s.

[sevenperforce]

The VTOL commuter craft are fun too.

I feel like his modeling software took a turn here.

"The rotors are not props, but variable pitch 7 blade rotors with IO Aircraft QUIET TECH© built in."

So they aren't props, just...propellers.

"If catastrophic failure occurs, it is also equipped a BRS (Ballistic Recovery System), which can deploy deploy and the entire aircraft will come down safely."

I want to know how to deploy-deploy too. "Ballistic Recovery System" sounds like "lithosphere-assisted braking" or "rapid unscheduled disassembly".

Supposedly its power supply is a 600,000 milliamp-hour lithium polymer battery. That doesn't tell us about its energy contents, but its motors are supposed to have 120-140 hp for each of four nacelles, so the discharge rate for these batteries needs to be on the order of 422 kW during hover, assuming 99% efficiency electric motors. The most weight-efficient electric motor in the world, the Emrax 268, outstrips a Tesla motor by 36% at a featherweight 11.56 kW/kg.  So the engines in those nacelles are going to mass something on the order of 36 kilograms alone.  He says, "this aircraft will take off easily and the rotors can spin up further to produce up to 1,800 LBS thrust then cycle down during forward flight." If we take the utterly preposterous assumption that level forward flight at 250 knots is possible at just 50% motor load, that's still 211 kW. A range of 160 miles at 288 mph requires about 33 minutes of flight so he needs a 69 kWh battery just for cruise. Consider that the Tesla 85 kWh battery comes in at 540 kg, so scaling for weight that gives us a combined battery and engine mass of 474 kg, or 1,045 lbs. Add 400 lbs for 2 passengers brings us to 1,445 lbs.

We can then subtract from the quoted maximum takeoff weight of 1,500 lbs to arrive at the vehicle dry weight of...55 pounds or 25 kilograms.

25 kilograms for the "composite ultra strong chambered airframe" that is made of a "fireproof composite resistant up to 2,500F" and is "multi layer chambered" along with the weight of the rotating nacelles and 8 variable pitch rotors.

No wonder it is "able to float in case of catastrophic failure over water"!!

[RealKerbal3x]

As has already been established, this guy and his website are full of mulch, but if he wanted to appear a little more credible he could have at least used the metric system. 

[sevenperforce]

2 minutes ago, RealKerbal3x said:

As has already been established, this guy and his website are full of mulch, but if he wanted to appear a little more credible he could have at least used the metric system. 

I know. I'm getting tired of converting back and forth.

I want to take a closer look at these not-prop rotors that can produce a combined 1800 lbs-force. That's about 2 kN per rotor and by my pixel count these rotors each sweep out an area of approximately 0.56 square meters. To manage that, the exhaust velocity needs to be 74.9 m/s, which doesn't seem that bad, does it? But since you can get power by multiplying thrust * exit velocity, you find that the actual power for each rotor is 149.8 kW. Variable-pitch propellers cannot get much more than about 80% efficiency, but even if we stretch and give him 85% efficiency, that means the total electrical power requirement is actually a whopping 712 kW at liftoff. The new combined powerplant mass is going to be 800 kg or 1,764 pounds.

Now it makes sense!! If the powerplant is over 1,700 lbs but the maximum takeoff weight is 1,500 lbs, the airframe must actually have negative weight! That's his secret! 

"These techniques include using exotic materials and advanced assembly processes that are currently unheard"

"Note, all technologies internally, engineering, and physics involved with U-TBCC are proprietary and non disclosable"

That's the secret! When he says "exotic materials" he actually means negative mass!! No wonder the "physics involved" is "proprietary and non disclosable"!

I know I'm just being mean at this point but this is funny AF

[Selective Genius]

30 minutes ago, sevenperforce said:

negative mass

You know what else uses negative mass? Alcubeirre warp drives.

You call him crazy but this man must have made an interstellar warp ship and get all these juicy futuristic aviation concepts from aliens.

Open your eyes, sheeple!!!

PS : On a side note, is anyone willing to mod these engines and planes into KSP? Or make replicas of his SSTOs? Should I make it a challenge?

Edited April 15, 2021 by Selective Genius

[sevenperforce]

1 hour ago, sevenperforce said:

If we take the utterly preposterous assumption that level forward flight at 250 knots is possible at just 50% motor load

I wonder how preposterous this is...this might not be fair.

These engine nacelles are able to rotate "60 degrees forward" for cruise. My mind is blanking -- does that mean the component of forward thrust is F*sin(60°) = 0.866 and the component of upward thrust is F*cos(60°) = 0.5, or is 100% of the thrust split at those proportions? Let's just say it's the former, which would tend to help him out (although that feels like a violation of the conservation of energy). So upward thrust will be 58% of whatever our forward thrust setting ends up being.

Where does that get us? Well, let's start with form drag. We know F = 0.5*C_D*A*ρ*v₂ but we don't know the drag coefficient C_D. We can guess, though. A Tesla Model S has one of the lowest drag coefficients of any vehicle at 0.24 but let's say we reduce this even further to 0.2, which is as "unheard" as many of his other claims. That same pixel count as before (completely ignoring those gigantic nacelles) gives me a frontal area of about 1.11 square meters. 250 knots is 129 meters per second.  Plug and chug, and you get a form drag of around 2.36 kN (note: we haven't even touched on parasitic drag or interference drag).

So just to deal with form drag at 250-knot cruise, the engines are going to need to be operating at a minimum of 681.3 N each (to account for the sine losses), or 34%. However, this does provide some cosine gains, since they'll be pushing 340.1 N downward, which helps reduce the needed lift and thus the lift-induced drag. 

What about that lift-induced drag, then? Well, the Martin X-24A lifting body had a subsonic L/D ratio of about 3.5, which was remarkably good for its size. I can't imagine the "Blackjack E" having a body-lift L/D ratio nearly this high with literally no wings at all. But let's assume it does. Loaded weight is 1,500 lbs which would require 6.67 kN of lift in fully lift-based flight, but the 340 N of upward lift from each engine will reduce the necessary lift to just 5.3 kN. With that very generous L/D ratio of 3.5 this means induced drag is 1.5 kN so we need to spin up the engines a little higher.

Increasing power to 50%, my BOE estimate, reduces needed lift to 4.7 kN and reduces induced drag to 1.3 kN, but we're still going to come up a little short. At 53% power, you can finally break even. Each nacelle is pushing 1.06 kN and the lift, drag, and thrust are all in balance. To achieve the 160-mile range you need 33 minutes of cruise at 379.5 kW or 208.7 kWh.

Liftoff takes place at 633 kW with a net upward acceleration of 0.067 gees. Let's assume you need to get at least 100 meters in the air before you begin transitioning to cruise. Kinematic equations tell us that the time t it takes to climb a certain distance Δx at a constant acceleration a is given by t = sqrt(2Δx/a). So ascent takes about 18 seconds. Flip those rotors forward and start accelerating. Drag builds up quickly but you've got a decent amount of power, so you hit 129 m/s after about 17 seconds.

However, you need about 2 minutes of hover time to ensure a clean landing approach at your destination. So ascent and descent require about 155 seconds at 633 kW for an additional 27.3 kWh, bringing the energy requirement to 236 kWh. Add a 5% reserve and a 96% depth-of-discharge limit, and your battery pack needs to carry 258 kWh. It will have a mass of around 1.6 tonnes or 3,614 pounds.

This is actually a really good demonstration of why personal electric drones just don't make much sense.

[sevenperforce]

2 hours ago, Selective Genius said:

PS : On a side note, is anyone willing to mod these engines and planes into KSP? Or make replicas of his SSTOs? Should I make it a challenge?

That's probably even more mean but I won't say no

[K^2]

2 hours ago, sevenperforce said:

I want to take a closer look at these not-prop rotors that can produce a combined 1800 lbs-force. That's about 2 kN per rotor and by my pixel count these rotors each sweep out an area of approximately 0.56 square meters. To manage that, the exhaust velocity needs to be 74.9 m/s, which doesn't seem that bad, does it? But since you can get power by multiplying thrust * exit velocity, you find that the actual power for each rotor is 149.8 kW. Variable-pitch propellers cannot get much more than about 80% efficiency, but even if we stretch and give him 85% efficiency, that means the total electrical power requirement is actually a whopping 712 kW at liftoff. The new combined powerplant mass is going to be 800 kg or 1,764 pounds.

Now it makes sense!! If the powerplant is over 1,700 lbs but the maximum takeoff weight is 1,500 lbs, the airframe must actually have negative weight! That's his secret! 

You just did more math than the page author did in their entire life. But I do like that negative mass take. I bet a lot of the designs can be fixed with that. Worst case scenario, you can always weld some mass to some negative mass, place that inside of electromagnet, and just use it to dump momentum. It's like a reaction wheel, but for linear movement. It basically solves every problem. Need a bit of extra thrust? Dump some momentum. Need to take off without noise and debris? Dump some momentum while still on the ground, then sip it gently for continuous hover. Need to raise orbit? Borrow some momentum and periapsis and dump it back at apoapsis. Need artificial gravity on board? Give the ship a gentle spin, then start dumping momentum for constant 1G on board and no net saturation. Then give me quarter impulse, Lieutenant Sulu.

[Shpaget]

Not to mention you could stuff your face with some anti mass desserts, to negate that huge lunch you had earlier.

It works for that too, right?

[sevenperforce]

24 minutes ago, Shpaget said:

Not to mention you could stuff your face with some anti mass desserts, to negate that huge lunch you had earlier.

It works for that too, right?

As someone who gained entirely too many pounds during the pandemic, I feel volume is more a problem than bulk density

[K^2]

33 minutes ago, Shpaget said:

Not to mention you could stuff your face with some anti mass desserts, to negate that huge lunch you had earlier.

You don't need anti-mass for that. Just anti-calories. And we already have that. It's called celery. Some scientists also speculated about using Casimir Effect to add anti-calories to food, but that remains entirely theoretical.

[JcoolTheShipbuilder]

10 minutes ago, K^2 said:

You don't need anti-mass for that. Just anti-calories. And we already have that. It's called celery. Some scientists also speculated about using Casimir Effect to add anti-calories to food, but that remains entirely theoretical.

Isn’t it that the body is so efficient that you still gain calories from eating celery? Like only 20% of celery calorie is used to process it I think?

 

hmm this went a little off..

also, did the guy post more hilariously incorrect things on that website? Hmm..

also, what is the difference in strength of a tank when it’s a sphere or a flat sheet? I’m pretty sure a sphere would be orders of magnitude stronger than a very thin tank made of the same material and thickness?

also isn’t having thin tanks of cryogenic liquid in thin wings bad for hypersonic flight due to extreme heat? Wouldn’t you want some sort of cooling there instead?

Edited April 15, 2021 by JcoolTheShipbuilder

[K^2]

25 minutes ago, JcoolTheShipbuilder said:

Isn’t it that the body is so efficient that you still gain calories from eating celery? Like only 20% of celery calorie is used to process it I think?

Really? I've always heard it as it taking more energy. But maybe it's from the same category as "10 % of your brain." Curious. I'll do some Googling later.

[SOXBLOX]

3 minutes ago, K^2 said:

Really? I've always heard it as it taking more energy.

I wouldn't be surprised if it really does consume net energy. A safer bet, though, would be bamboo. Or cardboard.

[Shpaget]

But those don't taste like cake. Nothing but cake does.

[kerbiloid]

A chicken cake tastes like chicken... cake.

And a chicken as well.

Edited April 15, 2021 by kerbiloid

[insert_name]

Did anyone else notice how little space there is for luggage on his hypersonic passenger plane? Has this guy ever traveled anywhere? Also how do the baggage loaders get in there?

[sevenperforce]

2 hours ago, insert_name said:

Did anyone else notice how little space there is for luggage on his hypersonic passenger plane? Has this guy ever traveled anywhere? Also how do the baggage loaders get in there?

Details, details.

2 hours ago, K^2 said:

Really? I've always heard it as it taking more energy. But maybe it's from the same category as "10 % of your brain." Curious. I'll do some Googling later.

Chewing up a stick of celery only takes about half a calorie of your energy, but your body burns 80-something calories per hour when you're just sitting there, and so the amount of calories you get from a stick of celery is less than the amount of calories you burn during the same time period.

3 hours ago, JcoolTheShipbuilder said:

also, what is the difference in strength of a tank when it’s a sphere or a flat sheet? I’m pretty sure a sphere would be orders of magnitude stronger than a very thin tank made of the same material and thickness?

also isn’t having thin tanks of cryogenic liquid in thin wings bad for hypersonic flight due to extreme heat? Wouldn’t you want some sort of cooling there instead?

He is very loud and proud about how he doesn't use liquid propellant; all his designs use GH₂ and GO₂ but supposedly stored at 16,000 psi. That's 1,100 bar.  Most pressure-density graphs for GH₂ don't even go that high, but at 0°C it's about 54 kg/m³ and at -100°C it's about 68 kg/m³. Liquid hydrogen has a density of 71 kg/m³ and that's at just 2.3 bar. So he expects us to believe that he can make conforming-shape thin tanks that hold 480X higher pressure than cylindrical tanks with a 31% better mass fraction.

I feel like he has very odd ideas about the interplay between density, mass, and volume....

"Overall fuel capacity for Raven is beyond 18,000 gallons (which liquid fuel weight would be beyond 140,000lbs), which since it is designed to be fueled by hydrogen; and oxygen for orbital capabilities,  that reduces overall take off weight greater then 140,000 LBS."

Does...does he think that compressing hydrogen produces a higher energy density but not a higher volumetric density??

[FleshJeb]

4 minutes ago, sevenperforce said:

He is very loud and proud about how he doesn't use liquid propellant

My dumb question of the day is: Is there a propulsive efficiency cost in the phase-change of the fuel from liquid to gas? I forget all my thermodynamics, and I am now frantically googling what "adiabatic" means.

[Spacescifi]

Yeah...laughing at real attempts to pass off scifi as reality is amusing when you know better.

 

I do think that based off KSP knowledge alone, anyone can design a vehicle that can do the job required...maybe not as good as scifi, but it can get the job done.

 

With enough staging, one can launch ANYTHING...not tied down.