Bolt Head Controversy

[waynep]

Most Gyros are well machined bolted things made of aluminum and steel with some composites and a shitload of hardware. Us Americans call the European models "plastic tubs". I assert that I can build a machine that is largely composite; eliminating most of the zillion parts that is lighter and stronger. I believe I can build an ultralight that could carry a 1000 lb payload on a ready to go 254 lb air frame. Nuts?

 

[gyrojake]

Actions speak louder than words, go for it.
Post pics as you build

 

[Jazzenjohn]

I agree with Jake, but it is a great challenge for yourself and fantastic to see someone strive for it! I've only built ultralight gyros and, although I believe they are built strong enough, I don't think they would be appropriate for 1000 pounds payload. As for the motor that would power such a beast, putting out 600+ pounds of thrust while still coming under the tough 254 weight limit, again, difficult... I'm anxious to see the build thread too. Build threads are very popular here, although becoming rarer lately.

 

[waynep]

Actually, I'm just going for a max 400 lb design payload for a max 650 lb MTOW. I'll post pics this winter.

 

[j4flyer]

Some of the reasons for the aluminum and steel combos of building is to have materials that have know strength and flex life. It is also a matter of sales. People are used to that type of construction and tend to purchase the product in larger quantities than composite. Now that composite construction has a foundation in proven strength it has begun to merge into the main stream a little more IE; Cirrus Aircraft, ICON etc. However, the cost of composite construction in man hours for a small unit run has prevented a lot of companies from going in that direction. Good luck in your endeavor. I hope to see the product.

 

[WaspAir]

On the other hand, composite construction has been standard mainstream stuff for sailplanes for half a century. I fly a serial production Standard Airworthiness glider that was built in 1968 (56 ft span, over 800 pound gross weight with 6+ g strength). GA airplane builders take to innovation with all the speed of an advancing glacier, even when the technology has been fully proven for decades by other airspace users.

 

[waynep]

Has anyone comptemplated a single piece rotor system? For instance, a composite rotor/hub bar with preset AOA and coning angles. No bolts. Likely a separate block to attach to the rotor head. This would present storage and shipping issues. However, point loads/stresses would be eliminated and a reduction in weight. I had been seriously thinking of doing a prototype. But I have big concerns about accuracy and jigging/molds to do this.

 

[waynep]

Did some calculations. It's possible to build a 150 lb craft (including small engine) that would be suitable for a 200 lb payload. That means a 20 to 25 hp motor would give decent performance. I'm not going there. But it is something to think about. This would be competitive with paramotor systems. If done well, this approach could open up a new class of enthusiasts. (Caveat, I write tech proposals for a living. Exploring various approaches is key to winning solutions. Some win. More don't)

 

[gyrojake]

Dude, you have some really great ideas, sure would like to see some building, typing is easy.

 

[waynep]

Dude, you have some really great ideas, sure would like to see some building, typing is easy.

Certainly some analysis paralysis on my part. I've spent years studying this stuff.

I've built up my shop. 'Got most all the materials. I'll be making progress during the winter months. I shouldn't whine, but I'm up in the mountains, by myself. But I can do this. I'll post some pics.

 

[PW_Plack]

It's possible to build a 150 lb craft (including small engine) that would be suitable for a 200 lb payload. That means a 20 to 25 hp motor would give decent performance.

That sounds like a calculation done using airplane assumptions. Gyros are draggy. The rule of thumb is 10 pounds-per-horsepower or less for good performance. So you'd be looking for at least 35 HP for the proposed machine.

That said, there are some good mass-produced engine choices in the 35-HP range. That would be exciting!

 

[waynep]

'Just thinking out loud here. I thought about this a little further considering trike and paramotor approaches. Extremely light systems could be built approaching paramotor weights: minimal frames including takeoff/landing gear, controls, a seat, motor, and rotor system at 80 lbs. MTOW at 300 lbs. Rotor system would be 30 lbs or so max. Flight time would be around 30 minutes. Market would be mostly newbie thrill seekers, those on vaca, the kids, and me. A towed version could done for around 30/40 lbs. New, lightweight blades and rotorheads could easily be made. Of course the money to be made would be in the 2 - 3 hours of instruction required. Super lightweight dual versions could be done to enable pro pilots to be alongside.

 

[waynep]

I retract my statement above that new lightweight blades could be easily made. If that were true, everyone would be making blades themselves.

 

[Kevin_Richey]

Ralph Taggert wrote that when he & his flying partner, Don Chubb, were flying their GyroBee creation, they experimented w/ using the Kawasaki 440 two stroke engine. Reported to be 40 hp, they found it didn't have sufficient power to even fly much more than in ground effect.

They estimated that the true power produced was along the lines of approximately 35 hp. It was a good idea for an inexpensive & available power plant, but all variants of the 440 (A & B?) couldn't equal what the true 40 hp Rotax 447 made.

Ralph indicated that using the 447 worked because they chose to use 25' diameter blades, instead of lesser diameter ones, to get the extra lift from the larger ones. Using the Rotax 503, w/ it's extra ponies over what the 447 has, due to it's heavier engine weight, busted the FAR Part 103 weight limit.

Engines that produces 20-25 hp, up through ones making 35 hp, simply do not have the necessary grunt power to fly extremely draggy, auto-rotating, rotorblades.

One could have a glimmer of hope that 35 hp might be enough if the airframe was super-efficient WRT streamlining it, and the pilot weighing <160#...

 

[Alan_Cheatham]

Of course the money to be made would be in the 2 - 3 hours of instruction required.

Two to three hours training time is unrealistic as experience with real world gyros would show.

 

[PW_Plack]

Market would be mostly newbie thrill seekers, those on vaca, the kids, and me. A towed version could done for around 30/40 lbs...

That target demographic sounds terrifying from a liability standpoint!

There's no real incentive to go lightweight or use more exotic materials with a towed gyroglider. Training newbies will require a second person onboard to instruct, which means even a 30-pound airframe will have an extra 200 pounds along, negating any value in experiencing the lighter machine.

You'd probably need insurance to do anything like a commercial gyroglider operation, similar to what parasail operators have. Both are subject to FAR Part 101, so gyrogliders which remain tethered to a tow vehicle would not be a complete wheel reinvention for insurance underwriters.

 

[BEN S]

I talked at length with Jim Vanek years ago about a one piece carbon fiber frame that you would step into/strap on and what would be necessary to bring to market an Ultra Ultralite gyro.
Its not that there aren't ideas out there that can't be done better stronger lighter faster, but you will never get around the one glaring fact that an actual Gyroplane manufacturer currently in the business pointed out to me so long ago, "to what end? who are the customers you think are going to buy it in numbers great enough to pay for the R&D and start-up costs? At best your looking at a couple thousand POTENTIAL customers in the pool, of those perhaps 10% would pay actual money. Of those 10%, how many will pay a lot more for a product that solves a problem that doesn't exist?"
So if your gonna build it, build it. But if you think the aviation world is going to beat a path to your door.....see how that's working out for Icon Aircraft!

 

[Vance]

'Just thinking out loud here. I thought about this a little further considering trike and paramotor approaches. Extremely light systems could be built approaching paramotor weights: minimal frames including takeoff/landing gear, controls, a seat, motor, and rotor system at 80 lbs. MTOW at 300 lbs. Rotor system would be 30 lbs or so max. Flight time would be around 30 minutes. Market would be mostly newbie thrill seekers, those on vaca, the kids, and me. A towed version could done for around 30/40 lbs. New, lightweight blades and rotorheads could easily be made. Of course the money to be made would be in the 2 - 3 hours of instruction required. Super lightweight dual versions could be done to enable pro pilots to be alongside.

It is my sincere hope you will be more realistic about training for yourself Wayne.

It is my observation that people without aviation experience take quite a bit of time and instruction to learn the basics of aviation.

Many people who didn’t believe this are dead.

Some survived to tell stories about how easy it was teaching themselves to fly.

Most I know who self trained recommend against self training.

Some think it is the way to go.

 

[gyrojake]

It is my sincere hope you will be more realistic about training for yourself Wayne.

It is my observation that people without aviation experience take quite a bit of time and instruction to learn the basics of aviation.

Many people who didn’t believe this are dead.

Some survived to tell stories about how easy it was teaching themselves to fly.

Most I know who self trained recommend against self training.

Some think it is the way to go.

I believe there are some people who should self train
They should also use plastic stick sockets, course thread bolts with standard nuts and lock washers.
Go cart shocks and a three thousand dollar paint job are how these usually end up sitting and never flown.
Go for it Dude, build the ultimate machine and fly it on your own, is my recommendation.

 

[ultracruiser41]

WayneP.......I’ll tell ya what......you are located in Boone, NC. We fly out of an airport in Wadesboro, NC.....we’re only about 3 hours from you. Come on down anytime....we’ve got lots of gyros....and we can answer any questions you may have....show you everything you need to know about gyros and even give you some free flights.

We have names of some great CFI’s and will give you all the information you need to safely get into this amazing world of flight. We’re at the hangar most every weekend so let me know when you’re available.

BarryK