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Australian-Built Hoverbike Prepares For Takeoff
Zothecula writes "Adventurous motorcyclists might be familiar with the thrill of getting airborne at the top of a rise, but the Hoverbike is set to take catching some air to a whole new level. With a 1170 cc 4-stroke engine delivering 80 kW driving two ducted propellers, the inventor of the Hoverbike, Chris Malloy, says with its high thrust to weight ratio, the Hoverbike should be able to reach an estimated height of more than 10,000 feet and reach an indicated airspeed of 150 knots (278 km/h or 173 mph). At the moment these are only theoretical figures as the Hoverbike hasn't been put through its paces yet, but Malloy has constructed a prototype Hoverbike and plans to conduct real world flight tests in a couple of months."
How exactly to they expect this thing to stop?
I see this scenario playing out:
1. Guy goes too fast on hoverbike
2. Kid runs after ball, runs in front of bike, then realizes the guy is riding at least 50 ft above him, then he gets his ball
3. Bike makes no attempts to stop since it is far above the boy on the street
4. Bike passes kid harmlessly remaining upright and under control
5. Kid looks at oncoming car in horror
6. Mel Gibson runs over kid and yells, "You Abo scum will not grow up to sleep with me wife!
FIFY
Sig Follows: "Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself." -- Mark Twain
So there's my flying car. About damned time.
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
Airplanes have to ability to glide to an extent, helicopters can auto-rotate. I seriously doubt that the rotors on this are big enough to auto-rotate, or that the designer made the calculations necessarily in order to design something that can auto-rotate.
You could use a parachute but parachutes take time to deploy and slow your decent so while effective at higher altitudes, at lower altitudes, like say the altitude at which you would be herding cattle, an engine failure would leave you heading towards the ground without enough time to deploy the chute.
I'd fly this is there were 2 engines such that one engine could power both fans, and 1 engine had enough power to at least hover and make a safe decent. Even then, I'd still probably bring a parachute.
Is your average helicopter ducted? No? Then its aerodynamics are not the aerodynamic comparison you're looking for.
This thing is a lot lighter than your average helo, and the ducting makes it more efficient in generating downforce.
Which isn't to say its claim of 10 Kft isn't an unsupportable guess. Just that your arguments are not sufficient to refute it.
Because a UH-60 with a max takeoff weight of over 20,000lbs, and a sectional area of a school bus is at all comparable to a single-seater with a max takeoff weight of 600lbs.
In other news, scientists say a 600cc sportbike is faster than an unladen Freightliner tractor powered by a 600 horse Detroit Diesel. Who could have guessed.
Constitutional rights may be respected, repealed, or modified; but they must never be ignored.
http://en.wikipedia.org/wiki/Autorotation_(helicopter)
"Cannot autorotate" is a polite way of saying this thing falls like a rock.
How can I believe you when you tell me what I don't want to hear?
anyone with even the most remote fucking grasp of physics
You used 0 physics to rebuke his claim. You only supported your argument with non-analogous airframes.
I don't know if getting to 10K feet is possible with this thing, and I suspect it isn't--it wouldn't be matter of just air density, but also the rider would need protection, like air and temperature controls. Also the horizontal wind speeds would be a whole different factor, and it's not clear that he's taken those into account.
But shit, if it can fly stably at 30 feet at 50 mph that would be good enough for me. I could get off the roads, and therefore avoid traffic and use line of sight to travel.
--
$tar -xvf
Why are you flying so low you can hit a kid anyway?
The kid is playing hover ball with his jet pack you insensitive clod.
I'd rather take this one, because it isn't vaporware...
"I love my job, but I hate talking to people like you" (Freddie Mercury)
anyone with even the most remote fucking grasp of physics and flight should be comfortable debunking his claims as a complete lie.
From your comments below, I take it you aren't one of those people. Here goes:
most commercial helicopters stall out at anything greater than 8000ft; most of the ones flying around my city stick to around 600-800 ft ceilings..
Those two statements have little, if anything, to do with each other. Helicopters generally stick to low (sub 1,000 ft) altitudes for a couple of reasons -- namely, there's usually little reason to fly higher since it takes more fuel to climb and the jobs for which they are often used tend to require low altitude flight -- not because they are incapable of flying higher. Also, the ceiling for a helicopter is dependent upon its forward velocity through the air. The faster the helicopter flies -- to a point -- the more lift the rotor blades create, and therefore, the higher it can fly, so be careful not to confuse the hovering ceiling with the service ceiling in cruise flight. They are not the same thing.
The CH-47 Chinook twin rotor helicopter is used by the USAF to rescue climbers on Mount Denali (McKinley) in AK.
Uhhh...no, it's not. The Air National Guard based at Kulis in Anchorage flies Sikorsky Pavehawks (militarized S-70s) and the Army at Ft. Rich flies the Blackhawk -- basically the same airframe as the Pavehawk, but outfitted differently. In Talkeetna, AK (where most climbers fly out of to reach Denali), there is a highly modified helicopter nicknamed the "Denali Lama". IIRC, it's an Aerospatiale -- but it's definitely NOT a CH-47. In fact, I'm not aware of anyone regularly flying a CH-47 in Alaska; at least I don't see them in Anchorage very often.
the highest altitude helicopter currently in existence is the AS350. A pilot named Didier Delsalle of France landed it on the summit of Mount Everest (8,850 meters) in 2005...and the record is entirely speculative/disputed.
...which is 29,035 feet -- three times the altitude this guy claims for his hover bike. While it may be a disputed record, there are plenty of verified accounts of helicopters landing and taking off well above 10,000 feet in mountain rescues (including Air Force Rescue 470, in which my brother-in-law was the PIC and for which, he won the MacKay Trophy).
finally, A blackhawk military helicopter with a 1700 horsepower engine still only goes ~190 kias.
And your point is? A Cessna 206 does 140 knots (the article doesn't say on what engine, but 206s typically have either a Continental O-470 at ~235 h.p. or a Lycoming O-520 at ~300 h.p.), but the amateur-built AR-5 will do 180 kts on 65 h.p. Let's see...the AR-5 has 1/5 the power and roughly 1.5 times the speed. Clearly you can't correlate h.p. to max speed on different airframes. In fact, there's a lot that determines how fast a given amount of power will propel an aircraft, for example, the drag from the rotor disk and how much of that engine power goes into lifting the aircraft. Your 1700 h.p. Blackhawk has a max take-off weight of 23,500 pounds, giving a power to weight ratio of 0.07 hp/pound. Since the designer of the hover bike is shooting to classify this aircraft as an ultralight in the U.S., that means he's limited to an empty weight of 254 pounds.
MCSE? No, sir...I don't do Windows. Yes, I am an idealist. What's your point?