Back to the basics ?
 

A while ago the early Bensen B-6 appeared on youtube.This gorgeous little gyroglider,actually a modified Hafner Rotachute,made me wonder why over the years the gyro's have grown in size dramatically.
Where the Bensen-Brock-Wallis machines where still "reasonable" in size,"modern" machines got higher-wider-heavier etc....
No doubt there are valuable reasons for increasing the figures but I don't know if they all are related to safe flying a gyro.Some may have to do with making it safer for the bystander.
Just for the fun I fiddled together a sketch of a two engine micro gyrocopter,also shamelessly based on the Rotachute.
No see-saw two blade rotor but independent flapping blades.Two small engines each driving his own prop having their own fuel tank.
It's just large enough to wiggle my body in and a guestimate is that it could weigh something like 60 kg (roughly 120 lbs)

What do you guys think? Should there be room to get back to "smaller is better" ?

Some flaws in your design, Cita
1) Two independent engines and propeller side? What happens if there is failure of one of the two?

2) Independent flapping blades requires independant drag hinge. Caution ground resonance !

3) your rotor seems about 15 feets. How much power do you hope to take off at low forward speed?

4) The rudder is in the wake of the pilot, and is not blown by propellers. How effective do you expect?

5) Independent tanks? It is the certainty of having to stop the engine the less greedy when the other has finished. Residual fuel is unusable.

But you are right to try to reduce weight. It is designers negligence added to the effect "snowball" that is inflation.

I have never been able to eliminate 2/rev shake from flap hinged and drag hinged 2 blade rotors except with a soft mast.

Chuck Beaty and his unique gyro, 1994 - YouTube

With a rigid rotor pylon, 2/rev shake was so severe as to be dangerous.

The same system worked OK on a gyro with flexible mast.

The rotor was hinged at its center with a hinge configuration similar to a door hinge and with outboard drag hinges.

The designs have increased in size for safety, more power, asthetics, etc.

Instead of constricting the machine to abid by silly weight rules, why not go bigger and make it safe, comfortable, powerful, etc?

A list that makes a bigger gyro better:

1: Pre-rotator
2: Suspension
3: Avionics
4: windscreen
5: larger tires for grass strips (bumpy ones)
6: Enclosure
7: good power (more than 50HP)

I believe an ultralight could be designed to incorporate some of these features, but not all. We've had one on the board for awhile, but other projects are more important.

Jon

Hope to have "answered" some of the remarks Jean-Claude.

Helo Chuck,

there's no rule that prohibits to use 3 blades I guess.It would make the rotor head a bit more complex and add some weight.
Hmmm....sounds like the first step to go bigger and heavier LOL !!

Cita

Hello Jon,

thanks for the remarks.

I guess that "better" is often used to replace "comfort" which in the end will add to safety I guess.

The list you gave indeed makes it more comfortable to fly a gyro but perhaps aren't neccesary to fly,like I've said,with the basics.

Windscreen-enclosure-avionics-suspension etc.. are those things that make it very comfortable but add weight for which you need more than 50 hp.....I think.

There are probably not too many people who would like to go back to the basics but that might be what could make it affordable in the future.
It's like getting in a car that was build in the 1950's,it doesn't brake as good,the roadholding isn't like today,acceleration is a fraction of modern cars etc... but........they brought people where they wanted to go 60 years ago and they still can do it today.
Are we willing to keep spending more and more for things that might not be neccesary ? I don't know and therefore the question.

Cita

Ok. Points on safety.

Avionics. Communication with other aircraft, GPS to know where you are/going, etc
Pre-rotator. short take-off in less than desireable areas for climb-out. No risk of falling into a prop trying to pat up the blades..
Suspension. Keeps cracks from forming in the frame or destructing other components from rough handling.
Windscreen. bugs, birds, etc.

Your right though. You need none of them to just fly :)

Hello John,

We don't need electric windows-air conditioning-automatic trunk opener-heated seats but......it's so damn nice to have it on your car LOL !! I guess it's no different on a gyro.

I think people knew where they were going before GPS (not THAT long ago) but they might not anymore in a couple of years without it.
Happened to me last year on the spagheti traffic knot in Paris. The GPS decided that it was enough and recommended a "U" turn on one of the most saturated highway's in Europe LOL !!!
No maps at hand and no additional handwritten instructions to which exit or by pass to take like in the old days.Very funny !!

Why go back to the basics when "better" goods are available.....to keep it affordable ?

My motor scooter (500cc Aprilia) is basic, but it does have disk brakes for great stopping and fuel injection for easy startup and smooth running. CVT belt drive which means no manual clutch or complicated transmission. Just get on start and twist the throttle to go. this type of system is simple not heavy and reliable. The point I'm trying to make is it is a modern and a simple design, with no radio, no roof, no windows, only 40hp, but it will do 100mph. and as safe as the drive wants it to be. The new ultralight gyrocopters are the same way. and I wouldn't trust the older styles.

With a rotor 15 feet, it takes more power to take off 380 lbs at 30 mph that 460 lbs with a 21 foot rotor.

Cita,

An interesting thread with potential, but what are the primary objective(s) that you are striving for? Low cost? Safer craft? Greater participation in recreational rotorcraft? Other?

____________________________

On the subject of controllability the two subjects of 2/rev vibration and partial weight-shift are of interest. They both relate to the force required by the pilot to control pitch and roll.

The following image shows the forces required for three small fixed-wing craft. Would one or more pilots comment on the forces required by the pilot for a standard gyrocopter?


http://www.unicopter.com/Midget_Mustang.jpg


Dave

Jean Claude,

I was looking more at a figure of MTO of 300 lbs making it a limited acces to bigger pilots.
I think there are small engines on the market which should provide enough power for a very reasonable weight penalty.
One of the reasons for two smaller engines is that the prop size can be reduced (higher rpm-smaller diameter) ,making it possible to place the thrust line lower.
I know that there is no such thing as "only gain" so there are disadvantages to every solution I guess.

Dave,

you summarized it quite good except I have my doubts that such a small machine can be "safer" than it's bigger brothers.

Affordability might be the motivation for more public general participation in rotor craft unless there is a trend to keep it elitary.

Perhaps nobody wants to go back to a car where you have to hand crank the side windows to allow some form of "air conditioning" and grow "Swarzeneger arms" due the lack of power steering.Perhaps we forgat that these cars could also transport a person from A to B in a safe manner, only our drive style has changed over the years demanding better brakes,acceleration,speed,comfort etc....but we pay a price for that,a high price.


Maybe gyro flying needs to get even more expencive before people start to ask themselves if it is worth the money and if a (modified) old Bensen style gyrocopter for example could give them the affordable pleasure they are looking for,I don't know.

In times where "everybody" wants to "resque everybody" it might not be so evident to take a few steps back and consider the possibilities if it could still be done with basic materials-design-performance etc....

Cita

Old Time
 

Cita, I'm with you. I started on a Brock/Bensen. Went to a Parson's 2 place then to a heavier Mad Max centerline thrust machine. I flew the most with my origional Brock/Bensen. 10 years later I am going back to the basics. Stock Brock KB-2 with either VW or Rotax engine. Prerotator because I'm getting older. Hand held radio. Chart on my leg if I am going someware. 50 MPH is just fine for me. The whole idea is to have fun. I dont need to spend $20,000 and higher to achive that. Alan

I've tried to keep to the lightest weight in my gyro. I weighed it this morning at 248.6 pounds but it is slightly different from this pic as I couldn't keep the seat tank and stay under 254. I believe it is the only UL legal gyro with a 4 stroke motor. I'm doing a few more things to reduce weight so I can fit a very small pod on the front and streamline it a bit. The next gyro will be physically smaller by a small amount than this one.