Helicopter Design - Idea Discussion

[Dennis15221]

I am not a pilot but I am an engineer. I've been thinking about designing a helicopter. One that is low cost, very easy to fly and safe.

 

Anyways, I would like to talk to some experts on helicopter design. Anyone want to explore some concepts?

 

I've been thinking about this for a long time(20 years) and I have an idea in my mind that I think will work. I'm not concerned about speed or ceiling at this time. I would much rather have a design that is very easy to fly, has a long range, low cost and maybe some good lifting abilities.

 

Dennis

[AdminLB]

Maybe you could by a design:

 

http://helicopterforum.verticalreference.com/topic/17581-want-to-own-your-own-heli-design/

[Dennis15221]

No, I'm not interested in BUYING someone else's design.

[aeroscout]

What's interesting to me about helicopter design is that in comparison to fixed wing, helicopters are still in their infancy.

 

It seems like there should be another technological advance right around the corner that will be revolutionary in helo design. Maybe you are the right guy to come along at the right time.

Good luck with it.

[Dennis15221]

Infancy? Maybe, don't know. I like what I see with the Sikorsky X2.

 

If I won the lottery, I might see my intended design come to life. The design I have in mind is similar to the Sikorsky X2. It uses fixed pitch coaxial rotors. I can't decide if the helicopter should be a hybrid(gas-generator feeding an electric motor) or a standard combustion engine.

[aeroscout]

Infancy? Maybe, don't know. I like what I see with the Sikorsky X2.

 

If I won the lottery, I might see my intended design come to life. The design I have in mind is similar to the Sikorsky X2. It uses fixed pitch coaxial rotors. I can't decide if the helicopter should be a hybrid(gas-generator feeding an electric motor) or a standard combustion engine.

I first saw the osprey concept in the early 80's. But that concept was no more than an updated version of a 50's innovation.

 

I also first saw the ABC in the early 80's. I saw that as only a slight improvement over the AH-56 concept that was Vietnam era.

 

I hope you could come up with something innovative that will light the aviation helicopter side of the world on fire. Something that would be so earth shattering that it would set convention aside. A new paradigm that would have the human race convinced that man was meant to fly.

 

Maybe a new form of propulsion, or flight controls, or incorporating nanotechnology, or anti gravity, or something out of science fiction like anti matter. Something that would bring the promise of the gold standard of fiction...the flying carpet of the future.

[pilot#476398]

How about a helicopter that can make private ownership more realistic to the average Joe? Like an R22 for the price of a truck!

[Eric Hunt]

Fixed pitch?? No cyclic control? You may have some problems with that.

[Dennis15221]

How about a helicopter that can make private ownership more realistic to the average Joe? Like an R22 for the price of a truck!

That is one of my goals. At least under $100k.

[Dennis15221]

Fixed pitch?? No cyclic control? You may have some problems with that.

What problems do you think may arise? I know that lift will be a direct function of the throttle instead of separate controls.

[palmfish]

What problems do you think may arise? I know that lift will be a direct function of the throttle instead of separate controls.

Controlling lift with throttle gets you going up and down. What about the rest of the flight envelope?

[Nearly Retired]

I'm sure the OP meant "fixed-collective-pitch" rotors. Obviously you'd need a way to control the tilt of the disk, but that doesn't mean the blades (of a two-blade system) have to feather individually.

[palmfish]

Obviously you'd need a way to control the tilt of the disk

Not if you employ differential collective pitch.

 

But you're assuming the OP doesn't know what he's talking about and I think he does, so even differential collective pitch is not option.

 

Fixed-pitch blades would be the simplest mechanically, and you could get yaw control by varying the RPM of the disks individually. But you still wouldn't have directional thrust.

 

A propeller (like the X2 has) would give forward thrust, but it would add weight and sap power, and still wouldn't let you go backwards or sideways.

 

I'm glad I just fly helicopters...lol

[Eric Hunt]

Look at old aeroplanes with fixed pitch propellors. They have to choose a pitch setting which is a compromise between fine pitch for low speed / takeoff and coarse pitch for high speed cruise. There is only one speed where it is ideal.

 

With fixed collective pitch, the lift must be controlled by changing the rotor RPM, like the cute little toy helicopters. But this doesn't scale up.

 

Get rotor blades strong enough to carry the airframe and some payload, and you have inertia. Rapidly increasing or decreasing the lift / RRPM will require the engine to be rather powerful and piston-powered - a turbine can't spin up or spool down as a rapid response like a piston can. You will have considerable lag between power application and the extra lift from the increasing RRPM.

 

With changing RRPM you have all sorts of other problems with designing the optimum pitch angle - helps with their RRPM governed to 100% of their design RPM do not have to deal with the changing drag figures, variable tip speeds.

 

And how will you deal with autorotation? With a fixed pitch at some setting well above flat pitch (or you won't take off) you will rapidly lose RRPM and go splat big-time.

[WolftalonID]

Rocket deployed parachutes? Maybe fixed pitch rotors will stop in an engine failure so that parachutes become viable means of safe recovery.

 

Dont want to consider ejectable rotors, that adds undo danger to persons on the ground in an emergency, plus the possiblity of an untimely malfunction.

 

Eric...I have wondered myself, why dont we see scaled up light weight rotors like toy heli's have? They have tremendous lift to weight ratio. Is it simply because they are so light weight autorotation would not be possible?

[Dennis15221]

Not if you employ differential collective pitch.

 

But you're assuming the OP doesn't know what he's talking about and I think he does, so even differential collective pitch is not option.

 

Fixed-pitch blades would be the simplest mechanically, and you could get yaw control by varying the RPM of the disks individually. But you still wouldn't have directional thrust.

 

A propeller (like the X2 has) would give forward thrust, but it would add weight and sap power, and still wouldn't let you go backwards or sideways.

 

I'm glad I just fly helicopters...lol

I do not want to consider pitch and roll movements. I'm intending to allow only 3 types of movement. Verticle - using the throttle control. And Yaw - using two clutches that will reduce one or the other rotor RPM. And forward and backward by tilting the two rotors.

 

I know that cross wind will be an issue.

 

As for the propeller (like the X2 has) to give forward thrust, I may consider this later on but the extra lateral thrust to add speed is more than I want to deal with at this time.

 

As for "Auto-Rotation", as I understand it the idea is to use the wind to drive the rotors during an unpowered descent. With the two clutch system, the rotors can be disengaged from the motor.

[WolftalonID]

If you intend the ship to fly...the. It WILL be subject to 3-D movement in the air. Pitch, and roll cannot be eliminated. Limited yes, but not eliminated.

[pilot#476398]

That is one of my goals. At least under $100k.

 

It would probably be cheaper to just invest in certifying an existing helicycle for mass production (instead of being home built experimentals)?

[Dennis15221]

 

It would probably be cheaper to just invest in certifying an existing helicycle for mass production (instead of being home built experimentals)?

I'm sure of that.

 

Another design that is very similar to what i want to do is the AirScooter. What I want to do is just beef up this design for longer range, greater lifting and simplified controls.

 

If I was able to build and prove out the design I have in mind, my next step would be to setup automated control for take off through landing sequences.

[pilot#476398]

Just watched a youtube of the AirScooter and well?,...I'd rather have an Eagle helicycle,...or an R22 with a turbine engine!

 

I guess I'm just more of a traditional helicopter design guy?

 

Good luck though.

[Dennis15221]

The Eagle Helicycle, R22 and Mosquito are all cute fairly low cost, light helicopters. Any of them would be fun to operate. I really do not want to design or create something that has been done so many times before. Making something smaller or more light weight is ok but it is not new.

 

My focus is not really on the sport of flying but rather the utility of it. I know that if I want to sell a vehicle, it will need to look cool. However for a prototype, looks are not important. The Volocopter comes to mind. The prototype was not good looking but it did prove that it could be done.

[palmfish]

As for "Auto-Rotation", as I understand it the idea is to use the wind to drive the rotors during an unpowered descent. With the two clutch system, the rotors can be disengaged from the motor. [/size][/background]

As Eric Hunt pointed out above, if you have sufficient fixed angle of attack to generate lift, then an engine failure will result in a rapid decay of rotor RPM. Free-wheeling clutches will let the blades continue to turn, but drag will slow them down until they stall. The helicopter will fall from the sky like a brick.

 

And if the angle of attack is minimal enough to somehow maintain sufficient RRPM for a "controlled descent," you still lack the means to steer during descent or cushion the landing.

 

I can't think of a way that a fixed-pitch helicopter can survive an engine failure at altitude.

[aeroscout]

I'm sure of that.

 

Another design that is very similar to what i want to do is the AirScooter. What I want to do is just beef up this design for longer range, greater lifting and simplified controls.

 

If I was able to build and prove out the design I have in mind, my next step would be to setup automated control for take off through landing sequences.

It sounds like you are going in the direction of producing a drone.

[WolftalonID]

I know as a pilot, I would have a very difficult time allowing the ship to auto depart.....not a very exciting idea.

I read an article where the military is doing research on unmanned troop transports....those guys boarding the thing would need some serious steel nuts to even consider letting a drone fly them.

 

Maybe down the road we will see more reliable AI systems come online, but I am not in a place to consider putting that level of trust into them yet.

 

I know many commercial airlines use auto land sequences everyday, and that alone is an amazing thing to me...

[aeroscout]

I know as a pilot, I would have a very difficult time allowing the ship to auto depart.....not a very exciting idea.

I read an article where the military is doing research on unmanned troop transports....those guys boarding the thing would need some serious steel nuts to even consider letting a drone fly them.

 

Maybe down the road we will see more reliable AI systems come online, but I am not in a place to consider putting that level of trust into them yet.

 

I know many commercial airlines use auto land sequences everyday, and that alone is an amazing thing to me...

Auto land is a good thing, but you have 2 pilots ready at the controls to take over if the autoland goes haywire.