Armed with gyros and a fly-by-wire control system it’s be trivial for a modern computer to keep it right-side up, regardless of its lack of natural stability.
With the controllable fan exit vanes and some smart software it wouldn’t be that hard to make the controls fairly easy to use.
Looking at his estimates for range & speed, I see reasonable values. You’ll be operating the engine at near full throttle all the time and I wonder about the longevity & reliability of a typical motorcycle engine under those conditions.
With that design, an engine failure would be catastrophic. It won’t glide & it won’t autorotate. It will simply plummet. So a parachute would be a highly desirable fashion accessory. As the article states
Finally, neither the US FAA nor the Australian Civil Aviation Safety Authority (CASA) would certify the thing as-is. It probably falls outside various exemptions for ultralights, and so would be subject to the full regulatory process for helicopters. Which is a shame because that’ll kill it as a product.
He could build his own toy & *if *it flies he can mess with it on sunny days at low altitude away from airports. But he’d never be able to commercialize it without serious regulatory changes & design changes.
This is the big killer IMO. The aviation home engineer field is just chock full of auto/motor cycle engine conversion boondoogles and failures. Everybody looks at approved aircraft engines and notes two things. They cost a fricking fortune and they “seem” low performance. A typical “real” aircraft engine might produce (totally made up numbers) something like 0.3 horsepower per pound. Then someone sees a some car or motorcycle engine that produces 0.5 horsepower per pound. So, just slap a prop on it. And or add a gear reduction to it. But there are always serious structural issues and vibration issues and cooling issues and constant high rpm issues and on and on. Invariably these things end up costing a fortune anyway and still have bugs in em.
A homebrewed and unlikely reliable engine? Used on something that can’t glide or autorotate? Hell no.
Is there some particular about FAA regs that would exclude it? I don’t recall autorotation being a requirement. There are a couple of general safety exclusions that might apply though. It could meet ultralight requirments, there have been a few helicopters that do. The structure would be really expensive if all made from CF though.
I think the general problem would be the lack of controlability in flight without cyclic or collective pitch control. Throttle control of lift has been problematic, and vectored thrust in similar devices haven’t worked out so far. Tandem helicopters have the added problem of a complex transmission that can fail in addition to a single engine.
Many small engines used in experimental craft come in close to 1 lb/hp for a naked engine. All up it’s usually around .5 lb/hp, or a little better. Helicopter performances does put unusual requirements on engines though. There hasn’t been much success in one man experimental or ultra-light helicopters.
Yes, I agree - I wouldn’t get on one without a parachute of some sort, and I’ve happily flown both ultralights and experimental homebuilt airplanes. The difference? The UL’s and experimentals I’ve flown were able to glide, this thing can’t.
(Oddly enough, though, the only two engine failures I’ve had were both in factory-built airplanes, a Cessna and a Citabria. Ah, the joys of aging aircraft!)
You could get it licensed as a homebuilt experimental in the US - maybe. You have to convince the local FSDO it’s at least theoretically airworthy and that might be a trick. Not impossible, but lots of paperwork.
It can not, however, be considered an ultralight under FAR Part 103. The 30 liter gas tank mentioned in the article works out to just under 8 US gallons - that’s 3 gallons over the limit for US ultralights. Of course, one could replace the gas tank, it’s a pretty trivial matter in the greater scheme of things, although that will, of course affect endurance. And no, you can’t put on a second gas tank, it doesn’t work like that. You could carry extra fuel as cargo, but not in a manner accessible in flight because that’s seen as cheating. And you don’t want to run out gas at 10,000 feet in that thing. The 231 pound weight comes in under the ultralight limit, but the cruise speed? 92 mph is way to fast for an ultralight. Having two engines disqualifies it as a light sport aircraft.
Sorry guys - in the US this has to be registered as a full up experimental rotorcraft, and you’ll need a private pilot - rotorcraft license at minimum to fly it, with a multi-engine rating on top. That’s what? Around $50k these days to jump through all the hoops? It will cost you more to get the license than to get the “hoverbike”, assuming it’s possible to build and sell it for the planned $40k.
The only way to bring this in as an ultralight is to somehow reduce the forward cruise speed. An artificial limiter is permitted, but you know folks are going to try to get around that almost immediately.
(Yes, oddly enough you can fly a multi-engine ultralight with neither lessons nor license required in the US. I will, however, point out that such entities seem to have undergone a Darwinian elimination from the world of very light aircraft.)
See above.
Please name one - I’m genuinely curious. Every “UL” helicopter I’ve seen has been either overweight, too fast, or somehow else disqualified from Part 103, which defines what an ultralight is. I’ve seen ultralight gyrocopters, but they aren’t quite the same.
I’ve seen homebuilt and experimental rotorcraft, though never been in one (and don’t have much desire to, to be honest) but they’ve all been single engine. In theory a multi-engine rotorcraft homebuilt is possible under the regs, I’ve just never seen or heard of a successful one.
Rotorway was pretty successful with its original Scorpion helicopter. The Eagle Helicycle is a new turbine-powered design that seems to be gaining popularity with few safety issues. The Revolution Mini-500 was extremely popular until its poor safety record became apparent. (There were many component failures, and complaints of poor quality of the kits.)
If there ‘hasn’t been much success’ with single-seat helicopters, I think that it’s not for lack of trying. I think instead, that it’s because most pilots reckon if they’re going to invest a lot of time and money, they want to be able to carry a passenger. That is, the ‘lack of success’ of single-seaters is more a factor of market forces rather than availability of suitable powerplants. Note that after the success of the Scorpion, Rotorway dropped it in favour of the Scorpion II two-seat design and then with the Exec, which is also a two-seater. For production aircraft, there’s just not a lot of demand for single-seat helis.
There’s the Mosquito Air. 254 pounds, 5 U.S. gallons fuel, max speed: 70 mph. According to the specifications page, ‘The FAA has ruled that the maximum speed of 63 mph normally applied to fixed wing ultralights does not apply to helicopters due to their unique power curve.’
From the FAQs:
The FAQ page for the XE/XEL states that the XE is not an ultralight, and requires a license; however the float-equipped XEL does fall under the U.S. ultralight regulations.
That’s an pretty good portrayal of the market. Except for Rotorway, which also sells a lot of helicopters overseas in certified categories, I wouldn’t call it much success.
Broomstick - There have been a variety of ultra-light one helicopters made with tip-jets, many of which have never flown much, or at all. Some others have been made based on the Adams-Wilson helicopter design going back decades. The Adams-Wilson rotor head and tail rotor head are reputed to be the original designs for the Rotorway Scorpions. Most workable forms of that machine needed a better engine than the original Triumph 500cc engine originally specified (engine size based on memory). Except for the Mosquito, I don’t know of one available in anything but plans form. Most small experimental designs could probably be made into ultralights by using only carbon fiber and titanium parts as the Mosquito did. With the max weight of 254 pounds for the aircraft, and a pilot considerably smaller than me, you can get by with a 50hp engine. I’ve also heard of plans from down under to make a peroxide tip jet ultralight.
There are plans on line for a death trap called the PropCopter, which has two small engines with propellors mounted at the end of the rotors. A backpack copter of this nature is purported to have flown briefly decades ago.
If you start looking into the variety of helicopter configurations that have actually been built, you will have an entertaining journey. It all makes the achievement of Igor Sikorsky more notable. The vast majority of helicopters ever built are based on his single screw with counter-torquing tailrotor design.
Of course the Rotorways being built now are all two-seaters. What I quoted was what you said about single-seaters.
We’ll have to disagree about ‘success’. The Scorpion was pretty successful, as were the Mini-500s. (They sold pretty well until they became noted death rides.) The Helicycle seems to be selling pretty well, though raw numbers are low because they’re so recent. What needs to be remembered is that helicopters are a pretty small part of the airplane market. Experimental aircraft are a small subset. Experimental helicopters are a small subset of the kit-plane market. Single-seaters are a small segment of the kit-built helicopter market. (Of course the success of the Exec is hard to beat.) So we’re talking about a niche of a niche of a niche. The market for single-seat helicopters is very small. Given that, I’d call the three single-seat kit-built helicopters I mentioned ‘successful’. If the criterion is a ‘flying motorcycle’ – i.e., something that represents a market segment analogous to motorcycle ownership – then obviously they’re very far from ‘successful’.
There was a time when just about any middle-class person who wanted to, could buy a ‘family flyer’ (Cessna 172 or Piper PA-28) or a little commuter airplane (Cessna 150/152). Those days are long gone. Especially nowadays, the success, in terms of sales, of any aircraft is quite relative.