Prandtl-d Aircraft

[trinidefender]

That still doesn't answer my question in any way. What other means can be used to control a helicopter other than using a cyclic? I.e. Cyclicly changing the blades pitch dependant on the position of the blades.

The original concept uses a swivel joint on the rotor mast controlled with two push pull rods, one for pitch the other for roll'
The design comes from autogyro development.
Unfortunately in a powered rotor aircraft the long control rods and potential wear results in vibration.
Pantograph systems for cyclic/collective have much shorter control links directly on the blades.
Major and variable changes in rotor blade angles to achieve powered flight using collective and cyclic result in a not ideal use of the blade aerodynamics and the main design requirement is safety within the flight envelope.

A teeter bearing autogyro rotor is far more efficient if designed properly and in conjunction with the rotor head and mast mounting, it needs NO collective or cyclic control.
The Wallis AG rotor has an UNLIMITED fatigue life.

I can see how that can work. As I have not flown with such controls I can't predict how it will react in a powered aircraft. It sounds as if the controls would be a little slow, something I definitely do not want when trying to hover with gusty winds.

No collective control? How would that work? The only way I can see possible is through rpm control but that brings in other major problems such as excessive conning and the resultant stress it puts on the blades. Retreating blade stall at high airspeeds and last but not least very slow responding controls.

Many small 2 bladed helicopters these days use a teetering hinge at the centre of their hub.

[Tommy Cookers]

Heelicopter is by William E Hunt and was published by Airlife in 1998

there is a chapter called 1940 - A positive alternative to cyclic blade control
Page 55 etc
with clever search terms enough of it might be readable via Google

[autogyro]

Semi hovering and hovering an autogyro with an unpowered rotor is highly controllable.
The W116 once flew in Brazil in hurricane conditions and the pilot watched a water spout form close to the aircraft.
All other aircraft were grounded with gusts up to 70 mph.
This was without either collective or cyclic control.

The experiments undertaken using tip jets on this rotor design used angled thrust from tip jets that increased blade incidence under power.
Lift variation was by tip jet throttling between 300 and around 400 rotor rpm.
Way below low airspeed tip sonic or stall problems.

Transition to AG flight mode was instant on shutting off the thrust jets with pitch adjustment.
Lateral control remained on rudder with pusher prop for forward thrust and rudder airflow, pitch and roll remained on mast pivot with control column links.
There is absolutely NO sensible reason to use tip jet powered rotor flight for anything other than take off and landing in still air conditions.
AG flight is safer, far more efficient both aerodynamically and in fuel use and much more stable due to pendulum stability.
Helicopters always fly in a close to crash unstable condition.
The Osprey is the biggest danger and I would NEVER fly in one of those.

[riff_raff]

What's the reason for all of this conspiracy nonsense regarding the US and UK aerospace industries? While it's true that the UK government provided an early jet engine design to the US during the war, US companies did a substantial amount of development work themselves to produce a serviceable turbojet engine.

As for using cyclic control of rotor blades to control pitch/roll of a rotorcraft, this technique is used because it is the most efficient approach for conventional helicopters. But other techniques can be used with other types of rotorcraft. Consider the typical quad rotor UAV. It relies on differential lift from each of the rotors by simply varying their speed for control functions. No cyclic and no collective.

[autogyro]

Riff-Raff
As for using cyclic control of rotor blades to control pitch/roll of a rotorcraft, this technique is used because it is the most efficient approach for conventional helicopters. But other techniques can be used with other types of rotorcraft. Consider the typical quad rotor UAV. It relies on differential lift from each of the rotors by simply varying their speed for control functions. No cyclic and no collective.

The quad rotor designs work very well in light short endurance applications using electrical energy.
It becomes ungainly and inefficient if scaled up or used with other power sources.
With this in mind I have looked at a compound power design based on the concept which could result in a supersonic combat drone with VTOL.
A replacement for the useless F35B in effect. (who needs carriers anyway)
I am not prepared to give details however.

[autogyro]

Riff-Raff

What's the reason for all of this conspiracy nonsense regarding the US and UK aerospace industries? While it's true that the UK government provided an early jet engine design to the US during the war, US companies did a substantial amount of development work themselves to produce a serviceable turbojet engine.

It is simply not nonsense.

[Tommy Cookers]

Semi hovering and hovering an autogyro with an unpowered rotor is highly controllable.
The W116 once flew in Brazil in hurricane conditions ........
There is absolutely NO sensible reason to use tip jet powered rotor flight for anything other than take off and landing in still air conditions.
AG flight is safer ..... much more stable due to pendulum stability.
Helicopters always fly in a close to crash unstable condition.

autos mostly had (crude) 'pre-rotation' because (in calm conditions) natural rotation needs a long (ie quite fast) ground run
such a ground run is a problem with uneven ground, due to the short wheelbase (as with a tailless aircraft)
windy conditions greatly help takeoff, but present other problems that should not be trivialised
a multi-passenger auto will anyway need a proper pre-rotation system

some such (Rotodynish) autos have been introduced in the US in recent years ?

helicopters for flight in instrument conditions of course have artificial stability
in this 21st century this must be relatively cheaper than it was before


btw the so-called Dunlop 'Maxaret' ABS so gloried by us Brits in the 60s eg when applied to the Jensen FF car etc ....
was an American design supplied to assist our nuclear V bombers in the 50s
supplied via the highest authorisation, apparently over-riding the general policy of the US miltary and industry

[autogyro]

Tommy Cookers

autos mostly had (crude) 'pre-rotation' because (in calm conditions) natural rotation needs a long (ie quite fast) ground run
such a ground run is a problem with uneven ground, due to the short wheelbase (as with a tailless aircraft)
windy conditions greatly help takeoff, but present other problems that should not be trivialised
a multi-passenger auto will anyway need a proper pre-rotation system

some such (Rotodynish) autos have been introduced in the US in recent years ?

helicopters for flight in instrument conditions of course have artificial stability
in this 21st century this must be relatively cheaper than it was before

Pre-rotation is not a problem
On light and medium AGs it is usually a simple clutched drive from the main propulsion source.
On the Rotodyne simple bleed air to the rotor tip jets
Ground run rotor spin up is a thing of the past
At least autogyros can TAXI which is a huge benefit over one position PARKED helicopters

The W116 proved many times a capability to take off land and operate in wind conditions that completely grounded ALL other aircraft types.
A capability with rotor spun up to take off fully loaded in 15 feet in AG mode in still air is hardly a problem with rough ground is it.

Please define 'artificial stability' is it something else to go wrong along with the rotor gearboxes and shafts on things like the Osprey?

[autogyro]

TC

btw the so-called Dunlop 'Maxaret' ABS so gloried by us Brits in the 60s eg when applied to the Jensen FF car etc ....
was an American design supplied to assist our nuclear V bombers in the 50s
supplied via the highest authorisation, apparently over-riding the general policy of the US miltary and industry

Having looked after Ginger Bakers three Jensen FFs in th 1970s, I would not sing the praises of a very basic ABS system so highly.
Only last week I had problems in our workshops trying to set up an ABS system on a VW Golf.
At least this system has a complex electronic circuit plugged into the ECU, even if excess pressure in the master cylinder throws it completely out.
The Dunlop ABS certainly helped do away with the V bombers brake chutes on the shorter runways.
I understand it was at the expense of rather more main gear tyres though.
Of course if we had available anywhere near the American budget for V bombers, at least two types would have ended up with the projected blown flap developments.
It is only because of America's SAC bombers and civil airliners that have forced huge long runways.
If it had been up to the British aviation industry short and medium plus military non strategic would have been VTOL and V bombers blown flap.
Would have saved a lot of concrete.

[autogyro]

Trinitdefender

I can see how that can work. As I have not flown with such controls I can't predict how it will react in a powered aircraft. It sounds as if the controls would be a little slow, something I definitely do not want when trying to hover with gusty winds.

No collective control? How would that work? The only way I can see possible is through rpm control but that brings in other major problems such as excessive conning and the resultant stress it puts on the blades. Retreating blade stall at high airspeeds and last but not least very slow responding controls.

Many small 2 bladed helicopters these days use a teetering hinge at the centre of their hub.

Conning is not a problem with tip jet power.
Stress on the blades is minimal and in the case of the W116 within its designated unlimited fatigue life.
Take off in gusty winds in a light AG would be in AG mode and complete in under 15 ft probably VTOL to ground datum.
Far more stable than any helicopter with powered rotor.
Heavy compounds like the Rotodyne use pantograph rotor heads for powered VTOL.
A modern development would be a combination pantograph teeter multi blade rotor.

[autogyro]

A light autogyro would make a far better combat drone than the current fixed wing types.
The W116 has completed anti tank rocket trials and small ship landings in the North Sea with complete success.
With four times the range of a helicopter even with a pilot a drone version would have a longer range than anything else available and the potential for a cruising altitude above 20,000 feet.
With NO rotor down wash it would be capable of highly covert operations even in daylight, there is NO surface disturbance.
At over 500 feet the W116 is almost silent from the ground because all the sound goes up through the rotor and not down to the target like a helicopter.
Airspeed would be in excess of 200 mph with a small target area and almost no heat signature.
Six of these AG drones could be operated from a 60 foot motor boat.
Brought into on scene action within hours rather than the two weeks to deploy Apache gunships to large airfield bases they would give a huge increase in military potential anywhere at any time.

[riff_raff]

So how is your concept different from the Carter Copter?

http://www.cartercopters.com/heli_150_images#

[autogyro]

So how is your concept different from the Carter Copter?

http://www.cartercopters.com/heli_150_images#

https://en.wikipedia.org/wiki/CarterCopter

I suggest you read up on the Carter Copter.
It does not compare in any way to proven AGs like the W116 or the Rotodyne.
Both the above have had a very successful service life.
Both the above have a much higher performance than the Carter Copter.
Modern versions of either the W116 or the Rotodyne would have performance way way above the CC.

The CC is an experimental aircraft exploring reduced tip speed ideas using heavily weighted rotor tips.
This is not the only and is definitely not the best method of reducing tip speed or tip stall conditions.
The Rotodyne regularly exceeded an airspeed of 200 mph with complete stability.

[riff_raff]

I suggest you read up on the Carter Copter.
It does not compare in any way to proven AGs like the W116 or the Rotodyne.
Both the above have had a very successful service life.
Both the above have a much higher performance than the Carter Copter.
Modern versions of either the W116 or the Rotodyne would have performance way way above the CC.

The CC is an experimental aircraft exploring reduced tip speed ideas using heavily weighted rotor tips.
This is not the only and is definitely not the best method of reducing tip speed or tip stall conditions.
The Rotodyne regularly exceeded an airspeed of 200 mph with complete stability.

The CC is somewhere between the W116 and the Rotodyne. The CC uses engine power to spin up the rotor enough to allow a vertical take-off and then relies on lift from a combination of the unpowered rotor and fixed wings for cruise flight, with thrust provided by an engine driven prop. The CC is much more refined than the Wallis autogyro. CC has also claimed a few performance records with their aircraft.

http://www.cartercopters.com/system/sdo ... 1391118473

[autogyro]

RR


The CC is somewhere between the W116 and the Rotodyne. The CC uses engine power to spin up the rotor enough to allow a vertical take-off and then relies on lift from a combination of the unpowered rotor and fixed wings for cruise flight, with thrust provided by an engine driven prop. The CC is much more refined than the Wallis autogyro. CC has also claimed a few performance records with their aircraft.

http://www.cartercopters.com/system/sdo ... 20(Records).pdf?1391118473

Explain how the Carter Copter is more 'refined' than the W116?

'Jump start' (rotor inertia VTO) was used in the very early autogyros through the 1930s.
As was the use of short fixed wings to augment rotor lift.
The W116 achieves a better comparative performance with only 60 hp and NO stub wings.
I would definitely conclude that the W116 is more refined.
The CC remains an experimental aircraft.
The W116 has been used in many operational roles.


Before Ken Wallis passed away we had plans to use a much more powerful engine and other developed features we had been working on.
Ken had always been reluctant to change the original design of the W116 which had met and improved on ALL its design requirements.
There are design areas on the aircraft which are far superior to any other type and they remain so.
The W116 is the ultimate efficient light rotor craft.
The Rotodyne is the ultimate medium/heavy lift rotorcraft.
The Carter Copter is another American attempt at using technology only partly understood on large government grants and marketing budgets.
The proof of this is in the operational market place and is at present led by the achievements of the W116 and the Rotodyne much as the results are there for all to see for the Harrier verses the F35B.