HoneyBee G2 Design Flaws

[Flynic3]

I apologize in advance for bringing up an old topic that is probably sensitive as some builders never received the kits they paid for.
I am curious about what may have been the flaws with this design? I read they had issues with the ultralight version and ultimately had a fatal accident in one. I was not necessarily concerned about the design of the Ultralight but the Light Sport single place versions. Were there also design issues with the non-103 single place HoneyBee G2’s? Does anyone have any first hand experience with the HoneyBee G2. What issues were experienced and was it attributed to a bad design? I am also curious if there is anything that could have been improved upon in the non-103 Gyros. One major and valid point I read about is the HTL of the HoneyBeeG2. Could this easily be corrected without a complete redesign such as lowering the motor mount to more of a CLT position? Could this be addressed by raising the horizontal stab into the thrust line? (IE Aviomania Genesis) The reason I am interested the HoneyBee G2 design is that it is the closest I have found to the design I am working on. I work with CNC Mandrel Tube bending equipment at my day job and could easily manufacture something similar. That being said I do not want to start with a flawed design...

I am not to sure about the engines they were using either or if they had anything to do with the problems at all. I am mainly wondering about the chassis design, layout, and proper horizontal stab etc...
I greatly appreciate everyone input and wisdom about this topic! I hope I did not rub salt in old wounds or bring up a topic that upsets folks here on the forum. This is purely for research purposes to see if I am even thinking along the right path...

Thank you all in advance and I look forward to hearing from you on this Subject!

Best Regards,

Nicholas Dawson

 

[Vance]

Some feel the high thrust line in relation to the center of gravity is a problem.

The person who designed it felt that near centerline thrust was a "red herring" and not important.

I have not flown one so I don't know how well they fly.

The fit and finish was nice.

Some of the load paths and the suspension looked a little iffy to me.

 

[Flynic3]

Vance,

I greatly appreciate yoir input and thoughts on the subject! It looks like it may not even be worth the hassle but I think they had something going here. I am curious if the designer is still around so I could pick his mind a little. Interesting though from what I read they were based out of Hastings, MI which is where I was looking at training from. I think they may have had a right idea but just could not execute it into a proper design with CLT. I am really interested in what could be done to improve this basic design. Even if I only ending up making one for myself, I think it would he worth it...

Thanks Again Vance!

Cheers!

Nicholas Dawson

 

[Doug Riley]

Jim Fields designed it.

The high thrustline creates a powerful nose-down moment. You'd have to test an actual example of the craft to determine the exact location of its CG. The vertical distance between the prop thrustline and the CG determines the lever arm, and hence the magnitude of the nose-down moment. Gyros with a lever arm (thrustline height) of only an inch or two can be stabilized in pitch by their horizontal stabilizers. Once the spread gets up into the half-a-foot-or-more territory, it becomes increasingly unlikely that the H-stab can supply a complete solution. The numbers just don't work.

None of us should give a bit of credence to what someone "feels" about this sort of design issue. The numbers are black-and-white and cannot be argued with. Four hundred pounds of thrust applied half a foot above the CG equals a 200-foot-pound nose-down torque, period. This is the simple arithmetic of a torque wrench -- not exactly sub-atomic physics. The arithmetic doesn't care what somebody "feels."

An additional issue with all gyros is torque reaction. Ideally, the tail surfaces should be designed and set up to create a roll torque that counteracts the torque applied to the frame by the engine-prop unit. A tall vertical fin and/or differential incidences on the two halves of an H-stab that's deeply immersed in the propwash, can accomplish this task.

If these two stability issues aren't addressed in the design, the rotor will stabilize the gyro in most BUT NOT ALL circumstances. The "not all" part is low-G, high-throttle flight. Low G is the same thing as low rotor thrust. With little rotor thrust, either the torque roll or the nose-down pitching torque can flip the gyro in the air. More often than not, the gyro in these conditions executes a combined snap roll and forward somersault, leading to a non-recoverable tumble and fatal crash.

Other design issues: Flexible fiberglass landing gear is certainly soft, but it's a pure spring, with no energy absorption. This tends to make an aircraft jiggle and bounce on the ground, like an old car with bad shocks. Ideally, landing gear includes a friction device of some sort that turns that "jiggle-bounce" energy into heat, so it's carried away by the air.

The curved down tube from the mid-mast to the nose may stiffen the mast in a way that we don't want. Two-blade rotors need to be mounted so that the rotor head can "hunt" back and forth a bit. An overly stiff mast forces the blades themselves to try to distort within their plane of rotation, which can lead to cracks in the blades themselves or in the rotor hub. The "gold standard' of mast flexibility is the Bell helicopter system of soft mounting, also visible in the Robinson helicopter.

 

[Brian Jackson]

The arithmetic doesn't care what somebody "feels."

My coffee mug.

 

[Flynic3]

Good Evening Doug,

Thank you kindly for the well written and informative post! What you have stated makes a lot of sense and solidifies my current feeling that I should abondon this design concept completely. I thought it may have been a good starting point considering the machines I work with on a daily basis. It was also the closest thing I had seen to the design I have been thinking about. I can bend any type of tubing in any direction at any degree bend angle with no creases. I can bend a tube up to nine times in a single sequence and can even incorporate multiple bend die radius in a single sequence. I have a lot of freedom with these machines to create complex tubular frames of any metal type. I have the machine side down quite well and can make the machine work for me. That being said, I am still learning the Design side and am currently working on getting Solidworks certified through the EAA. I have a lot of learn but am anxious to use the tools at my disposal to create something! I greatly appreciate your input and the wisdom you have shared. It means a lot to me and I appreciate you taking the time to explain this to me!

Brian,

I Love the Mug! Very True!

Cheers!

Nicholas Dawson

 

[Alan_Cheatham]

Nicholas,

The Airbet Girabet gyros may be more in line with the method of construction you are considering.

 

[Flynic3]

Good Evening Alan,

Thank you for the post my friend... I have never seen those before and they look like a cool little machine. I could easily create that sort of design and more than likely they are just using NC roll benders to produce those sort of bends. I may be wrong but they all look like simple roll die type bends which are easy to make. I definitely like their designs though and it gives me something to get the creative juices flowing...
I can create some pretty complex tubular structures with ease using these machines. I can make up to nine bends on one piece of tubing at any angle and in any direction for each bend, if that makes more sense. So there is a lot of potential for design when it comes to a tubular framed Gyro... I just need to come up with a proper design! I guess if I could explain the idea in my head... it would be a similar style design to say a powered parachutes tubular frame in tandem with a lot less tubing. I would have to make sure the attachment of the upper cage wasn’t to high up on the mast to allow flex. I would think it could be done properly with 3-4 tubes as the main structure, with a center main beam that would extend into a curved tail structure. Then of course the main Rotor mast and engine mount down the center bringing everything together. If this makes any sense whatsoever this is kind of what is floating around inside my head. It would obviously have a lot less tubular structure than a powered parachute but that was the only thing I can think of that is similar. I hope this gives you a little bit of an idea I am kickin around. I have a lot to learn when it comes to gyro design and would love some input and creative thinking...

Look at what Dick Degraw does with lightweight tubular frames in his designs and you can see there is some merit in this style design...

Best Regards,

Nicholas Dawson

 

[Doug Riley]

Nicholas:

In professional aircraft designs, bent metal tubes are not used in the primary structures (they are used as supports for fairings and curved surfaces covered with fabric, as well as exhaust systems). The reason is simple: a force, by definition, is a push or pull in a straight line. Forces don't bend or travel around corners.

For example, the bent under-the-prop tail boom seen on the current crop of amateur-designed Euro gyros is, on the professionally-designed Air & Space 18A gyroplane, made of a welded truss of straight steel tubes, and is merely covered with a sheet-metal fairing. This welded-truss construction is more weight-efficient than a bent tube of constant diameter and wall.

The bent tube has the (to me, less important) virtues of low fabrication cost and perhaps a certain aesthetic look.

Of course, small, certified general-aviation airplanes have long tail cones -- again, almost never built out of curved metal tubes. Instead, these tail cones are made up of thin, sheet-aluminum riveted to bulkheads formed (again) of thin sheet aluminum. Such structures are amazingly weight-efficient.

Dick DeGraw, a very knowledgeable designer, uses straight tubes and trusses, as you'll observe.

Bent metal tubes can be convenient in many devices, but they are not especially useful in aircraft structures, where rigidity and strength-to-weight ratios are so important.

OTOH, compound curves are excellent in composite structures. These materials are strong but very limber -- they lack rigidity when laid up as flat panels or straight, slender members (e.g. fishing poles).

People who really want to design a gyro airframe should learn a bit about space frames (3-dimensional trusses, such as the steel frame of a Piper Cub), beams, columns and shear members. The arithmetic is not especially difficult. The craft skills used actually to build this type of frame are steel welding, sheet-metal forming and riveting -- in addition to the familiar drill-press and metal-saw work.

 

[Vance]

A gyroplane structure is pretty simple Nicholas, as evidenced by the Bensen design consisting of extruded aluminum tubes riveted together with plates..

Just put the big parts in reasonable locations and manage the inherent vibration from the rotor and engine.

In my opinion none of the loads on the frame are very high as I have not been able to get beyond 2.2 Gs in any flight regimen.

The further back the empennage is from the center of gravity the more effective it is.

Part of why the American Ranger flies so well is because it has a very large empennage placed well back from the center of gravity.

It is nice to have the changing load of the fuel near the center of gravity so that the responses to the flight controls don’t change much as the fuel is used.

I prefer near centerline thrust but many gyroplanes are flying well with very high thrust lines in relation to the center of gravity.

Suspension is nice and I prefer a free castering nose wheel with differential braking for steering; also a very simple design.

I prefer engines designed for aviation because they remove a whole layer of development from the process.

Designing and building a gyroplane is a big enough project without adding the challenges of debugging a conversion engine.

 

[Flynic3]

Good Evening Doug Riley and Vance,


Thank you for the very well written explainations and I appreciate it. What you are stating makes complete sense and I guess in a way that is my goal of this design would be to use the bent tubing for a composite enclosure support. I was kind of grouping bend tubing and tubular frame structure together in a way because I can see incorporating both in a way. I greatly appreciate the wisdom and insight you have given on the subject of Gyro, as I am very much learning. What is done in one industry for strength is frowned upon in another for weight and complexity. I am very interested in learning tubular space frames and am extremely interested in building a Little Wing LW4 or 5. This would be a perfect project to learn such design I would think...
It is always difficult to explain ideas in my head and need to start playing with CAD again. It will help better convey some of the ideas that I have... more than likely most of them are flawed in someway or another. I have to start somewhere though I guess and that is one reason I post ideas here in order to gain insight! Insight from some of the best of the best, I might add! Everyone here is a gentleman and a scholar... it is much appreciated! I did find a design that was closer to what I had in my head regarding the bent tubing. It is Called the Pagotto BrakeGyro Naked GT. I don’t know about the skids, maybe for training purposes?



Best Regards,
Nicholas Dawson

 

[Steve_UK]

Do you know how many Naked Brako gyros are out there flying.

 

[Doug Riley]

I'd want more detail about the mast construction. It appears to be quite stiff fore-aft, which is a bad idea unless some other means of allowing the rotor spindle to move in response to the rotor's 2/rev vibes is provided.

The old cliche advice we've given to new gyro enthusiasts for decades is still sound: Don't start out by "imagineering" some cool new design at home alone. And don't buy somebody else's one-off design,or untested design, either. Instead, attend a big flyin (Bensen Days is coming up), see the gyros, get rides in several. If you're still jazzed, take lessons and buy a BOX STOCK gyro with a popular engine, a good reputation and lots of units out in the field. Fly the pants off your box-stocker, then sell it for a decent price (because it's a known quantity, there will be a market for it) and then go imagineering if you must.

People who design before becoming experienced gyro pilots (and learning a bit of engineering) have had a poor record of success. In fact, more than one has died, or killed his first or second customer, in his creation.

We don't want to spoil your fun, just save you a bunch of money, frustration and heartache!

 

[Flynic3]

SteveUK,

Based on your response I would assume there are not that many flying.. ;-).

Doug Riley,

I agree completely with everything you are saying my friend. At this point I am only imagineering and that is one reason I post my thoughts here for review by the experts! I will be attending Mentone and Oshkosh this year... I plan on spending a lot of time getting up close to the Gyros and speaking with owners. I will hopefully be starting my flight training in April but may take a drive down to Shelbyville for an Introduction flight with Brent Drake if the weather gets better. I am currently in the PRA ground school with Tim O Connor and we are currently going through our FAR AIM. I am looking forward to learning more about Gyros and design. I would love to get more hands on with a project and wish there were more builders in my area to assist. There are a couple projects I am looking forward to working on with my local EAA chapter 132 but they are all FW. Luckily there is a Gyro Pilot in my chapter who has been flying since the Bensen 7 days and is a DAR. I am hoping to learn more from him as he has designed and built an OshKosh award winning Gyro.
I am hoping to purchase a SportCopter Vortex in May and I was incredibly blessed to have met the owner. The Gyro and Sport Pilot community is amazing and I appreciate everyone I have met! I greatly appreciate your advice on this subject and I agree with you completely! At this point I am only dreaming and working through ideas. I look forward to meeting everyone at the Conventions and hope to attend as many as I can this year.

Best Regards,

Nicholas Dawson