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Electric powered Gyro any thoughts?

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Empirical

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Just saw that on that jump-takeoff video (post #37), the engine power was just 60hp (could have been electric) and the rotor was spinned 1.75x faster (with 9kg[20lbs] tip-weight) at 490rpm (vs 280 in flight) and a gross weight 340kg (750lbs)! But Carter wasn't the first to pre-spin the rotor of an autogyro for jump-takeoff. It was Cierva, the autogyro invertor who developed and "refined the procedure so that jump takeoffs were routine" ...in 1933! Watch this late 1930's video:


(obviously those jump take offs can be done a lot slower by slower increasing the pitch angle)
 
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autoreply

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Yeah, that's pretty close, though I'd like them to apply it to a "certified" car, like the Lotus Elise or another compact car. That solves the majority of the problems with the flying car. This likely doesn't meet the crash-standards and most other requirements.

That mast is a great idea.

Except if you don't mind the lack of yaw control while you take-off/land vertically (for just a few seconds), assuming you are in an open space.
If you can't control the craft, it's pretty useless to make it VTOL. A STOL-aircraft needs less space to put it down.
But we don't have to!
The change and evolution comes in steps.
Nope. To make it work, a lot of things have to go together. Look at it like a high-speed-train. Everything (rails, electricity, railway stations, permission to drive, actual train) needs to be there, before it makes sense. The whole system needs to be there before it works. Electric cars are a great example too. If you don't have enough charging points, nobody buys one. If you don't have enough electric cars, nobody builds charging stations.

Flying transportation is vastly more complex:
*Need 90% of cost reduction in aviation... right
*Need fully electronic controlled airspace
*Need bad-weather outfit, comparable to a jet
*Need dedicated landing strips that have automatic landing systems and is communicating amongst different craft.
*Need series of at least a couple of 100,000 units to make it profitable.
*Needs to take around 800lbs of "safety stuff" a car is required to have.

Many of those are contradicting. ALL of them have to happen at the same time. I recently read the story of the (Dutch) PAL-V. Assuming their product is technically viable (it's not, like any other flying car), I'd expect the cost to be in the tens of billions of euro's... for our little country alone.

It's nice daydreaming and many investors put their money in it, turn after turn. That doesn't make it a viable means of transportation, from a technical or economical point of view.
 

Culleningus

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Thanks for all the inputs guys.

Another totally hypothetical means of generating or regenerating electricity is via the reciprocating teetering?
Blade lead-lag whilst more or less redundant on newer designs might also act similarly.
Without knowing how this might affect autorotation, possibly adversely, its hard to know if there is in fact any merit in such an idea.
Interesting however.

In general the 'consensus' seemed to indicate here that (as was stated previously) ANY energy drawn from the rotors movement/s requires a proportionate addition of propulsive thrust to achieve the same state of affairs in flight (as without a generator).

On another tack...
The main obstacle for roadable transport (apart from width of undercarriage) is the blade length of the gyro which has been very neatly addressed on the SKY CYCLE:
http://www.youtube.com/watch?v=2QPYoyyQ0MY&feature=related

The Pitcairn AC-35 1930 design also had a relatively small rotor diamer, which like the Skycycle folded for road towing.
Already mentioned above.

Presumably more blades allows a smaller rotor diameter.

Someone mentioned strong wind capability and I think the following demonstrate the facility for STOL with a good headwind:
1)http://www.youtube.com/watch?v=ukbGtD2LN-4

Here's a 'HELPING HAND' approach:
2)http://www.youtube.com/watch?v=nY8SmllLcIU&feature=related

Dave
 
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autoreply

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On another tack...
The main obstacle for roadable transport (apart from width of undercarriage) is the blade length of the gyro which has been very neatly addressed on the SKY CYCLE:
http://www.youtube.com/watch?v=2QPYoyyQ0MY&feature=related

The Pitcairn AC-35 1930 design also had a relatively small rotor diamer, which like the Skycycle folded for road towing.
Already mentioned above.

Presumably more blades allows a smaller rotor diameter.
Nope. If we're looking at a helicopter or propeller, to generate the same force (static thrust or lift), we need more power for a smaller rotor area.
124d28983fc1317821c9de5d7e352546.png
That's the reason the Osprey (V-22) needs so much power.

If we're looking at a gyro, the rotor isn't driven, but still consumes power. We can use formulas to calculate the higher (push-prop) power, but we can also look it, the way we look at aircraft.

The rotor on a gyro is nothing more than a wing, albeit with rather low Clmax and very high drag. Going to a smaller wing/rotor means higher stall speeds.
L/D won't change that much if the rotor is downscaled (neither would a wing), so let's assume L/D remains the same. Let's assume the L/D a rotor is 4 to 1 and the given wing we compare it to is 15 to 1.
This means that if we reduce the wing/rotor area by 75% (half the span, half the chord, half the rotor diameter) we have stall speed that's twice as high.
Power is drag times speed. Drag is 4 times higher (goes by the square of the velocity) and thus total power required is 8 times higher.

Extra blades in fact make the rotor less efficient. One blade is optimal, two is the most optimal for a practical application. More blades makes it possible to increase the absorbed power for a slightly higher induced velocity (and thus lift/static thrust), but it requires more power for an increase in lift as the same blade area in extra rotor diameter.

The only 2 reasons to limit rotor diameter are:
*Blade speed limits (transsonic limit)
*Practical limit (vehicle dimensions)

Here, bigger really is better :)
 

Culleningus

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Thanks.
I have noticed however a tendency to still opt for 3 blades, on many designs.
Dave
 

Dana

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Yeah, that's pretty close, though I'd like them to apply it to a "certified" car, like the Lotus Elise or another compact car. That solves the majority of the problems with the flying car. This likely doesn't meet the crash-standards and most other requirements.idea.
Well, there was the ill fated Mizar (Ford Pinto with Cessna Skymaster wings):



-Dana

Beam me up, Scotty, it ate my phaser.
 

Topaz

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Tsk, tsk, Dana. Bombing helpless citizens with Pintos - especially Pintos with people inside - will never sit well with the FAA. ;)

The problems with "flying cars" are entirely regulatory. Molt Taylor built a practical flying car back in the '50s. It's bad enough trying to certify a production airplane. Then you've got to do all the crash-testing and certification stuff for production road vehicles. It's why you see so many "roadable aircraft" as three-wheelers: Three wheels means it's a motorcycle, and the road-certification requirements are vastly less complicated and expensive. But then, your customers have to have a motorcycle license to drive it...

This isn't even touching the pilot certification requirement. If you think the FAA is going to let people fly over inner city or suburbs without a pilot's license - whether there's some automated system on board or not - I have this bridge I'd like to sell you in NYC.
 

Dana

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Tsk, tsk, Dana. Bombing helpless citizens with Pintos - especially Pintos with people inside - will never sit well with the FAA. ;)
Hmmm, perhaps... though I would pay money to see (from a safe distance, of course) a Pinto fall from 5000'! :) Preferably empty, of course, though I might be willing to "volunteer" a certain few politicians as passengers...:ermm:

-Dana

Thinking for yourself is like most addictive behaviour. It is frowned upon by all right thinking people and is bound to get you killed sooner or later.
 

Topaz

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Hmmm, perhaps... though I would pay money to see (from a safe distance, of course) a Pinto fall from 5000'! :) Preferably empty, of course, though I might be willing to "volunteer" a certain few politicians as passengers...:ermm:
You have my utter and complete (and for the Secret Service, tongue-in-cheek) support for any and all aspects of that endeavor! :gig:
 

Culleningus

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Right.
Here's a sketch of the concept to date.
Waterborne/otherwise.
Gyro rotor becomes sail.
Gyro Rotor becomes generator in this mode.
Dave:
GYRODRAWG.jpg
 

Topaz

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Not to be negative or anything, but as-drawn the pilot's arms are supporting the entire weight of the aircraft, keeping it from pivoting around axis point on the raised mast. In fact, he's even got some mechanical disadvantage going on there.
 
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Empirical

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Nice scketch Culleningus,

but I see the following problems:


1. If you really meant to be controlled as it is drawn, where the rotor support in flight would be the pivot point, then definitely this is an impossible design -as also Topaz said.
But that alone is easily solved if a fixed mast is added behind the pilot where it can lock onto it in flight position to be well supported, having the generator (if one is used, instead of a transmission to the motor) + the axis control mechanism mounted above, but on the moving part.

2. The vertical tail surface should be made much lower (e.g by splitting it at the tail edge) because the rotor blades should have enough space to angle backwards with the axis control + their own flexibility!

3. There are permanent obstacles in front of the pilot! Personally I wouldn't accept that, no matter what. Even if it was made as a double support, leaving space in the middle.

4. Also a surface or a mast just behind the propeller will make it sound 10 times noisier (or more)!

5. You should calculate what the maximum safe wind speed is, bellow the point that it could turn over the autogyro if suddenly blowing from behind (eg a strong gust). Many decisions should be based on that (on the design stage).

6. I like that airplane-like type better, although a tractor is less efficient than a pusher.

7. The front part, doesn't have to be as thick and square as in a gas version (which results in increased losses). Electricity let's you make it as aerodynamic as possible! This would compensate at some degree for #6.

8. Note that the increased humidity + salt in the air above the sea during a windy day are bad for the health of (especially) a high voltage electric and/or electronic circuit or device. To make it 100% immune to that, you should make sure you'll be listed in the Guinness book for the perfect insulation! :)
 
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Culleningus

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Heres my original scheme completely modified as a result of your suggestions Empirical (most of which I was aware, hadn't considered the prop wash noise, but many thanks, I hadn't included many of them for simplicity you see)
Yes there ARE some major technical headaches (eg.water+batteries). Not insurmountable? Added to which Dana rightly points out safety in wind generator mode. The CG can be lower if the batteries are sealed somehow within the front of the sponsons (floats).
Its an A frame arrangement this time, more drag but less weight.
Gyro22.jpg
The scale of the pilot is too large in relation to the rotor (should be about half that shown)
& I have shown 2 possible motor arrangements (location B in front of the Fin)
Now I would be really interested to know about any tricks to keep the rotor diameter down?
Contra rotating rotors for instance placed on the same axis?
Biplane rotors?
Dave
 
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E

Empirical

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Yes there ARE some major technical headaches (eg.water+batteries). Not insurmountable?
No, it is not insurmountable, it is just more difficult to make everything water-proof and still dissipate all heat reliably and efficiently, be operational, serviceable, the battery pack interchangeable etc. It's not as difficult as it is to make a safe autogyro (see bellow)!

I have shown 2 possible motor arrangements (location B in front of the Fin)
You cannot decide the final arrangement without knowing everything about autogyro theory and how each decision affects performance and safety. Eg how high can you place the rotor? Does it have an advantage if placed higher or lower? Where it should be placed in relation to the CG? How far can you place the propeller from CG as a tractor and as a pusher and what other design decisions will be affected or how you could compensate for that if needed? etc etc Plus, you should experiment (with a scaled model) to uncover any hidden factors and verify the design.


Now I would be really interested to know about any tricks to keep the rotor diameter down?
Contra rotating rotors for instance placed on the same axis?
Biplane rotors?
Dave
A contra-rotating arrangement would result pretty soon to a blade collision between the two rotors, because the blades are flapping up and down in each rotation. This information was provided in the resources I had suggested in post #12.

Other configurations would require to develop an entirely different autogyro with the advantage of small rotor(s) -probably trading some other advantages.

The CG can be lower if the batteries are sealed somehow within the front of the sponsons (floats).
Culleningus, the choice of CG height and in general the CG placement for the autogyro is critical! A wrong decision might be fatal! Although it seems a low CG would make the autogyro more stable during flight since the fuselage "would hang from the rotor", that would only work while the rotor is properly loaded (high rpm and positive angle) and acts as a large wing. In case it slows down for whatever reason while the propeller still works, this would make the autogyro go nose down and start rotating around CG while loosing height quickly with no hope to recover!

=======(unloaded rotor)
|
|<-- F (propulsion)
|
CG ....becomes center of rotation!


After I realized this, I decided to search the web in order to verify it and/or find additional safety issues. Here are some more resources:
_______________________________________________

Safety issues and design tips:

The Book of the Autogyro (Index page -The whole site should be read thoroughly including all referenced links!)


some of the many must-read pages from the above site:

The Book of the Autogyro: Possible Problems with an Autogyro

The Book of the Autogyro: Tips for designing an autogyro

The Book of the Autogyro: How to Behave if you are Rotating


Another site with some theory plus some more issues:

The Theory of the Autogiro
_______________________________________________

For convenience and completeness here are some safety-related pages and pdfs from the site I suggested in post #12: EDIT: (currently the site is down, probably for maintenance..):

http://www.tervis.fidisk.fi/gyrosafety.html

http://www.tervis.fidisk.fi/Gysafety/Loosingfaith.pdf

http://www.tervis.fidisk.fi/Gysafety/N-15GX%20Accreport.pdf

http://www.tervis.fidisk.fi/Gyroincidents.html
_______________________________________________

"Advances in understanding autogyro flight dynamics"
http://eprints.gla.ac.uk/4962/1/Advances_in_the..._Flight_Dynamics.pdf

"EFFECT OF HORIZONTAL TAIL ON THE STABILITY OF THE VPM M16 AUTOGYRO"
http://www.aero.hut.fi/pubs/reports/AALTO-AM-18elektroninenversio-2_1.pdf

(The above info is NOT enough, look also at amazon.com there are a few books)
_______________________________________________

MY conclusions from all the above:

A. Too many safety issues about autogyros whether they are caused by design error, or "pilot error". Most "pilot errors" though are actually caused by poor design or design errors!

B. Too many design-decisions can seriously affect safety. Even if all the above suggestions were implemented correctly, no 100% safety is guaranteed. Even the rotor, can be quite complicated, unstable and fragile having hinges or being purely elastic. So much for the "simple" and "safe" autogyro!

C. Even experts and pros, including researchers that have build autogyros or have tested them in wind tunnels, arrive to different or contradicting conclusions and some times they even make mistakes on the input data!

D. It seems there is no detailed analysis available of all safety issues and behaviors for the autogyro. Not much bibliography either. Most experts do not elaborate enough.

From the previous suggested site:
"...recently some quite mysterious explanations have been given for zero-G accidents. One reason for this is that no pilot, so far, has returned alive from a zero-G flight to tell us about the experience."

This shows that no actual research and development is going on! They are not testing real-size autogyros via remote control or those who do, are keeping their data for themselves (for their companies)! So whom are you going to trust and what data?

In sort: Current autogyros are far from being 100% safe and I'm NOT talking about extreme conditions. Just conditions that 100% safety is always expected from such a vehicle. So I think autogyros are not mature yet. But I'm sure they CAN be improved and become 100% safe in their operational range.

Until then ...personally I wouldn't want to fly an autogyro anymore, whatever type, not even as a passenger of a highly trained pilot! I've lost my faith in augogyros! :dis:



My suggestions:

Now if you still want to take the risk and continue, first you should read all available resources about autogyros (all of the above + any additional links and books you can find) and completely understand the theory, the safety issues and the design challenges! Then you should ask yourself again if you still want to continue.

Next you absolutely need to verify your decisions building a relatively large remote controlled scale model e.g 1:3. After improving that model, you should make the real one and test it with a dummy load via remote control in all possible flight conditions until you are sure there are no safety issues inside its operational range. If and when you achieve that, you should be confident enough to get in and fly it!

Note that you'll need plenty of time to develop one (it took years for Cartercopters and still they had several accidents).
 
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Culleningus

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Thanks Emp.
There's alot of food for thought in there (much of which I had given some attention to).


Devotes might say:''Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect.''— Captain A. G. Lamplugh, British Aviation Insurance Group, London. c. early 1930's.

In truth: This hides the fact that SOME areas of aviation like you say are definately 'more fraught' than others:

''The danger? But danger is one of the attractions of flight.''
Jean Conneau, 1911.
Its all the more reason to consider the merits of a jettisonable rotor, one which from a static line pulls a chute, since the rotor would separate cleanly from the airframe by default.

Dave
 

Culleningus

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Thanks Emp.
There's alot of food for thought in there (much of which I had given some attention to).


Devotes might say:''Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect.''Captain A. G. Lamplugh, British Aviation Insurance Group, London. c. early 1930's.​

In truth: This hides the fact that SOME areas of aviation like you say are definately 'more fraught' than others:​

''The danger? But danger is one of the attractions of flight.''
Jean Conneau, 1911.​

Its all the more reason to consider the merits of a jettisonable rotor, one which from a static line pulls a chute, since the rotor would separate cleanly from the airframe by default.

Dave
 
E

Empirical

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In truth: This hides the fact that SOME areas of aviation like you say are definately 'more fraught' than others:​

''The danger? But danger is one of the attractions of flight.''
Jean Conneau, 1911.​
I think we are not attracted by the danger itself -our self-preservation instinct wouldn't allow that, but by the challenge of a difficult worthwhile achievement (dangerous or not) which would be the ticket to participate in the game of nature's "natural selection" (this IS instinct-driven) where we might be rewarded IF we succeed, having then more chances to propagate our (successful) genes to the next generations!

My view about danger in aviation is that aviation CAN and SHOULD be safe -even for large airplanes with hundreds of passengers. Those companies are totally responsible for all the fatal outcome of their accidents because they do not develop any safety systems at all that would protect the crew's and passengers' lives each time something goes wrong. They just consider them as numbers, possibilities and losses along with their crappy planes. We are still too primitive to take this seriously.
EDIT
: In other words, we've misunderstood the airline companies' disinterest in investing in airplane safety, as justified incapability next to an impossible task and we all have accepted the jack-pot fatal risk as granted. We are happy too because "aircraft accidents happen rarely", so nobody does anything to that direction!

As for a light or ultralight, it would be foolish to die just because somebody else did a poor, careless design and failed to consider case c and case e. Even more, if the engineer does a poor job when he is developing one for himself! Why risk when you can be safe AND have fun?

Its all the more reason to consider the merits of a jettisonable rotor, one which from a static line pulls a chute, since the rotor would separate cleanly from the airframe by default.
Sorry, I'm not sure I understand what you mean, can you explain a bit more?

 
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Culleningus

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Hi Emp.

Over the years it just became apparent that some advocates of one discipline or another become over zealous with their portrayal of poorly investigated accidents being invariably due to some sort of pilot impropriety or other.

If you've ever flown a plane with a less than obvious control defect mostly the observer will not immediately accept this explanation as to why you struggle to control it!

On the subject of the Autogyro 'chute its linked to the Foche-Angelis U boat gyro. I will try to find details.

Dave





I'm actually trying to
 

byronhead

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Since power required to push a gyro is measurably less than the power to get it off the ground I was thinking a tri blade that jumps off the ground then flies using an electric motor pusher once airborne. The prerotar could be plugged in to an outlet on the ground then disconnect as part of the jump. Gyros fly without stalling once airborne. Any ideas appreciated.
 
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