advertised in the back of Popular Science? It’s always been a dream of mine to order the plans and build one. Well, that and being a blackjack dealer in Alaska. I thought with all the different life styles and viewpoints here at SDMB, maybe somebody’s already done this. If this is you, share your story. If this isn’t you, please tell me it’s still a cool idea.
What kind of helicopters? I’ve built radio controlled ones, is that what is advertised in the back of popular science?
No, it’s a personal helicopter. Seats one, with the engine right behind the seat. The ones I’ve seen have 3 wheels on the bottom in a triangle frame.
OH I see… sounds more like a gyrocopter to me. That would be a kick.
A true form helicopter is so hard to fly and complicated mechanicly, I cant imagine being able to just build one and fly it from plans in a magazine.
I don’t have a pop. sci. on hand, but I remember distictly that it is called a helicopter, and it certainly looks like one, albeit much smaller with no cockpit.
Breck—I believe that you are refering to ULTRALIGHT AIRCRAFT ; in this case, helicopters.
I suggest that you post in General Questions, & retitle it something like “Ultralight aircraft/helicopters–built one?”
This may be more availing.
At first glance, it seems some are ultralights and others not (weight being the determing factor).
Here’s a homebuilt helicopter page offering several.
Here’s a neat looking one, the Aeros helicopter.
Finally, here’s a guy selling his homebuilt chopper.
Looking at some of these sites can make you wonder why you don’t see these things all over the place.
I know what you mean, and my SO wants one, always has. I usually try to keep my mouth shut about what a foolish undertaking this would be. And I find, it usually passes.
WOW! too damn cool. Now I HAVE to get me one!
I take back what I said…
Thanks for the links, beatle.
I’ve thought about building one of the Rotorway helicopters, or a Mini-500. I think the single-seat Mini-500 goes for about $30,000 (I haven’t checked the links), and I think the two-seat Rotorway (which has been around a lot longer) is about $60,000. Then you have to build them.
I’ve seen Mini-500s online, built and flying, for sale for about $20,000.
There are some things to remember: Homebuilt helis are in the Experimental category. That means that (technically) you can’t fly over congested areas (cities); but you could probably get a waiver. If you buy an already-built Experimental aircraft, you don’t inherit the right to do major work on it. You’ll have to take it to a certified mechanic. You may not use an Experimental aircraft for hire (no selling rides!).
One poster mentioned Gyroplanes. This requires a seperate license. To fly a helicopter you need at least a PRIVATE PILOT - ROTORCRAFT - HELICOPTER license. If you want to fly a gyro, you need at least a PRIVATE PILOT - ROTORCRAFT - GYROPLANE license. They’re not interchangable, but you can “add-on” to your existing license. (Oh, I guess you could have a Recreational Pilot license… but why not get a “real” one?)
Unless you are supremely confident in your engineering abilities, you should think hard before building a helicopter from plans. They are complex machines that require a lot of expensive maintenance. Better to get a kit from an established company.
You might consider a Robinson R-22. They run about $150,000 new, and can be under $100,000 used. One thing to watch out for is the rebuild (remember I said they require a lot of expensive maintenance?). R-22s must go back to the factory in Torrance, CA after 2,000 hours. You’ll get a factory-rebuilt engine, new rotor blades, transmission overhaul, paint and interior, plus whatever other maintenance needs to be done. That’ll set you back around $70,000 for the whole thing.
The other likely certified helicopter is the Hughes/Schweizer 269/300 series. A new Schweizer 300CB costs about $195,000. I’ve seen a 1961 Hughes 269A for $50,000. Trade-A-Plane lists a few mid-70s Hughes 300s for $80,000 to $100,000. Unlike the Robinson, where everything needs to be rebuilt/replaced at the same time, the Schweizer’s schedule is staggered. It’s probably cheaper in the long run (for the 300CB). The 300 has a lot more power than the Robbo (it’ll carry two 225-pound people, plus 35 gallons of fuel), which might be handy in mountainous regions.
Some people buy an aircraft, run it out, then sell it. Even if it’s half-way through TBO, there’s still a lot of flying left for one person. Often the aircraft can be sold for as much as, or more than, the purchase price. And this is after you’ve flown it all that time! Doesn’t always work that way, of course; but I’ve heard it from people who have done it.
Personally, I’m looking at the Hughes/Schweizer option; but I haven’t decided which route to take: Buy cheap, fly it out, then sell it; or buy new (as if!) and keep it. Better get my Instructor’s ticket first though…
I thought this thread might draw you in.
A question (keep in mind I barely know squat about flying, but I can chew on math and physics when needed) occurs. In looking at the cheapo choppers (particularly the ultralight class) I notice they run toward 2 and 3 blade designs. Most commercial and military choppers I’ve seen in my life are 4 blade machines, although I’ll note remembering that the Soviet’s Mi-24 Hind was a 5 blade machine and I think the U.S.’ heavy lift chopper (Sea King?) has, maybe, 6 blades.
My question would be: What is the best way that you, a helicopter pilot, can explain to me, a querying amateur, the relationship between performance and the number of blades a helicopter uses?
At first pass I would think more blades = more feet on the ground (uh, perhaps not the best expression, in light of context) - I think I meant more traction, more bite, greater responsiveness when maenuverability is a question. But there is undoubtably a cross of the curves where performance v. reliability comes to the fore.
Well, I have to confess that I don’t know for sure why certain numbers of blades are chosen. A WAG would be that an engine makes a certain amount of power and that you need a pair of wide-chord blades or a trio (or more) of narrow-chord blades to absorb the power. Longer blades could be used, I suppose; but that would mean you’d need a longer fuselage to keep them clear of the tail rotor. There’s also an issue of the blade tips reaching the speed of sound if the blades are long enough. But power isn’t the only consideration. A Robinson R-22 has a 160 hp Lycoming derated to 134 hp max t.o. (incidentally, the “derate” the engine by putting a red line on the manifold pressure guage) and it uses a two-blade, or “semi-rigid”, system. The 180 h.p. Schweizer 300CB has a three-blade, or “fully articulated”, rotor system. A Bell 206B uses a 420 shp Allison engine and uses a semi-rigid rotor system.
So in answer to your original question: I don’t know.
I can tell you a little bit about rotor systems. A semi-rigid, or “teetering”, system has two blades. For aerodynamic reasons that I won’t go into here, helicopter blades have to “flap” (think of it as a blade making a sine wave along its path). In a semi-rigid system the blades flap as a unit; one goes up and the other goes down. There is a “teetering hinge” in the middle to allow this. The other hinge is the “feathering hinge” that allows the blades to rotate about their longitudinal axis. By increasing the angle of attack collectively, the heli rises into the air; by increasing the AOA cyclicly, the heli banks or moves forward or backward.
A three-bladed (or more) rotor system can be “fully- articulated” or “rigid”. A fully-articulated system has individual flapping hinges (as opposed to the teeter hinge on the semi-rigid system) for each blade, feathering hinges, and “lead-lag” hinges. The lead-lag hinge allows the rotor system to compensate for the corriolis effect; the individual blade speeding up or slowing down with respect to the rotating rotor system. A rigid rotor system uses the flexibility of the blades themselves instead of using flapping or lead-lag hinges, and only has the feathering hinges.
The simplest system to build would be the semi-rigid system. It needs no “exotic” materials for very-flexible blades like on a rigid system, and doesn’t have the extra parts of the fully articulated system.
Multi-bladed rotor systems are susceptible to “ground resonance”. If you land too hard on one skid, or if the shock-absorbers on one side are not working correctly, a blade may be forced forward on its lead-lag hinge. This would create an imbalance that may destroy the ship. There are two actions that may be taken immediately: Raise the collective and get back into the air, or dump the collective and set it down.
IMO, Frank Robinson chose a two-bladed system, and I think amatuer builders use two-bladed systems, for their simplicity. The lack of ground resonance might be a factor, but anyone who is properly trained can deal with that. I don’t know about the performance question. Maybe we have some engineers in the house?
Do NOT buy a Mini-500. Do not fly in one if you have the chance, even for free. They are deathtraps. On engine failure, they do a violent nose-over and tend to crash. Several multi-thousand hour helicopter pilots have died after engine failures in the things.
And you WILL have an engine failure. The stupid design uses a Rotax 2-cyle engine running at something like 112% of rated power, thus causing engine failures roughly once every hundred hours or so. And the worst kind of failure - the engine tends to seize up, thus putting immense stress on the rotating components.
The construction violates many accepted engineering principles. For instance, the pushrod ends for all the engine controls are nylon. So if you have an engine fire, expect your controls to become useless shortly thereafter.
The nuts on the tail rotor assembly are nylock nuts, such as are used in model airplanes. FAA specs call for castellated nuts with a cotter pin on any rotating surface due to the forces involved.
Very few Mini-500’s are flying, and many of the ones that were flying have crashed. The accident rate in this thing is something like one for every 30-40 hours of flight time, vs maybe one for every 20,000 hours of flight time for other light aircraft.
The Rotorway Exec is a much better example of a homebuilt aircraft, but I think Rotorway went out of business a while ago. (So did Revolution aircraft, the makers of the Mini-500).
There’s another homebuilt helicopter that is often advertised in the back of Pop Sci, which has been in there for more than 20 years, despite never having had a single flying example.
The ads in Popular Science appeal to wannabe’s and dreamers. If you want to be serious about homebuilt aircraft, go pick up a copy of EAA’s “Sport Aviation”, or “Kitplanes” magazine (although that latter is known for never publishing a bad review of an aircraft, so read it with a grain of salt).
I always wanted to get one of those 6-wheeled amphibian vehicles in the back of Pop Sci. Oh yeah, and the bugs too. Those look killer.
Well! It sounds like the Mini-500 isn’t the way to go!
Rotorway Int’l is still in business, but I think they were out for a while several years ago. They are currently making the Exec 162F. Their page is http://www.rotorway.com
dhanson, you have a lot of information there. One question though: How would seizing the engine put strain on the rotating components? There must be a “freewheeling unit” that automatically disconnects the rotor system from the engine in the event of an engine failure.