How long have you got if the engine(s) go quiet
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How long have you got
As my last reply seems to have dissapeared i try again. I have developed a rotor system that overcomes the problem of how to get high inertia without having to have a huge hub and heavy blades to carry the loads. Not only can i give scratch your ear time, but the rotor is far more efficient as far as tip losses are concerned. Having had a university do the becessary FDA which backs up my own data, the only unknowns are the effects in foreward flight. Now whilst the uni tell me they can give answers to this, unlike me they do not work for nothing. As they already have my one arm and a leg, i cannot hop or eat without the other. The rotor system is more efficient and yet lighter than a pair of 22 blades and hub. What i need is the man that is going to give the financial clout to make and develop a full size rotor system Bug
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This is the ring rotor then? Have you contacted OEMs?
I gather there is DTI government money for this type of project.
Also Sergei Sikorsky is retired, but amazingly approachable and enthusiastic. Frank Robinson would probably have similar interest, and a good starting point for this. If nothing else both will offer sound advice. In Europe it is more difficult because organisations a tend to be just that. The best you can hope for is an interesting PhD project, although this can have good long term commercial benefits.
I imagine your ring rotor will be more expensive to manufacture than a conventional system, so i would try to estimate performance benefits in terms of additional payload or range. This can be offset against the increased component cost and potentially maintenance costs.
You are talking cash, so i would present your idea as a business case. Even the most enthusiastic engineer understands it is return on investment which pays his mortgage etc...
I gather there is DTI government money for this type of project.
Also Sergei Sikorsky is retired, but amazingly approachable and enthusiastic. Frank Robinson would probably have similar interest, and a good starting point for this. If nothing else both will offer sound advice. In Europe it is more difficult because organisations a tend to be just that. The best you can hope for is an interesting PhD project, although this can have good long term commercial benefits.
I imagine your ring rotor will be more expensive to manufacture than a conventional system, so i would try to estimate performance benefits in terms of additional payload or range. This can be offset against the increased component cost and potentially maintenance costs.
You are talking cash, so i would present your idea as a business case. Even the most enthusiastic engineer understands it is return on investment which pays his mortgage etc...
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Just wondering how quickly you have to react to the engine(s) going unexpectedly quiet and putting down the collective
If it's not within a second it will be done,
there's nought else that will be fun
tet
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The problem with approaching people is that you obligate them almost automatically. I suggest that you patent your invention, then enter serious talks with airframers after getting non-disclosure agreements with any that you reveal details to.
The problem airframers have is that every guy with a hot idea tells them something, then 5 years later the company develop something vaguely similar, and the guy sues. The cost to defend the technical merit and prior history of the company's work is horrendous, so company employees are schooled to return any unsolicited info unopened.
This is a common problem in Hollywood, with screenplay ideas.
If you cannot find someone to help fund patenting the concept, it is one measure of the idea's essential worth.
The problem airframers have is that every guy with a hot idea tells them something, then 5 years later the company develop something vaguely similar, and the guy sues. The cost to defend the technical merit and prior history of the company's work is horrendous, so company employees are schooled to return any unsolicited info unopened.
This is a common problem in Hollywood, with screenplay ideas.
If you cannot find someone to help fund patenting the concept, it is one measure of the idea's essential worth.
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bugdevheli...is this your invention?
Does it matter if you don't drop the collective in this helicopter after an engine failure? Will it still fly?
http://www.clipaday.com/videos/how-c...helicopter-fly
Does it matter if you don't drop the collective in this helicopter after an engine failure? Will it still fly?
http://www.clipaday.com/videos/how-c...helicopter-fly
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Interesting to see how little rotors flex with different revolutions. You can actually see how each rotor takes on same shape as it passes through the same point in the azimuth.
Strobes are a good way to slow down rotor dynamics.
Strobes are a good way to slow down rotor dynamics.
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"Ang on Syd" ? That sounds a lot like Tony Hancock....
But so soon I digress.
In my days instructing in R22s, I never once kept the RRPM in the green range after chopping the throttle on a student, during the climb.
So the answer is gunslinger FAST! No matter what the heli. Quick pilots live. Slow ones have scary deaths-but when was it ever not so.
Which spurs me to remember a long-shelved project: develop a hydraulically- dumped collective link to cause the heli to immediately enter autorotation in the event of engine failure.
Hmmm. Perhaps I'll talk to my aeromodeler friends first.......
thekite
In my days instructing in R22s, I never once kept the RRPM in the green range after chopping the throttle on a student, during the climb.
So the answer is gunslinger FAST! No matter what the heli. Quick pilots live. Slow ones have scary deaths-but when was it ever not so.
Which spurs me to remember a long-shelved project: develop a hydraulically- dumped collective link to cause the heli to immediately enter autorotation in the event of engine failure.
Hmmm. Perhaps I'll talk to my aeromodeler friends first.......
thekite
Following the loss of the Bristow Wessex off Norfolk the AIB did a lot of work on the reaction time following a complete power loss for an aircraft of that size.
If someone has access to the accident report that should have some definitive figures.
If someone has access to the accident report that should have some definitive figures.
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"Some folks suggest a slight application of aft cyclic immediately prior to...or at the same time one dumps the collective..."
MD500D + E and EC350-B3 = absolutely true. The aft cyclic starts upward airflow through the rotor immediately and helps slow the helicopter to the best auto-rotational speed.
I have no R22 or R44 time, but from many of the chopped-off tail-booms in them (especially the 22) , I don't think I would be real inclined to move the cyclic aft rapidly in a Robinson.
MD500D + E and EC350-B3 = absolutely true. The aft cyclic starts upward airflow through the rotor immediately and helps slow the helicopter to the best auto-rotational speed.
I have no R22 or R44 time, but from many of the chopped-off tail-booms in them (especially the 22) , I don't think I would be real inclined to move the cyclic aft rapidly in a Robinson.
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thekite,
There are many manufacturers of reliable electric actuators now. R22 has an electric throttle govenor, so machine is almost asking for an electric collective actuator. It need only respond fast enough to keep Nr constant as aircraft alters autorotation descent (in all flight regimes). As long as servo is only strong enough to overcome friction, pilot can overpower it for flare or manouvre - in practice it could just turn off once collective has been auto auto'd.
Keep system simple to start with, so just have system drop collective when buzzer sounds then disconnect. Later incarnations could take a signal from rotor Nr needle (I imagine it is a tacho signal), to trim for a specific Nr thus accounting for any cyclic movement to convert airspeed into Nr.
Once you get this system to work a phone call to Uncle Frank might get you a licence agreement. Then you start talks about including auto cyclic control as part of R44 SAS system.
BTW PM me if you want a resource in engineering community. I'm pretty busy, but interested.
There are many manufacturers of reliable electric actuators now. R22 has an electric throttle govenor, so machine is almost asking for an electric collective actuator. It need only respond fast enough to keep Nr constant as aircraft alters autorotation descent (in all flight regimes). As long as servo is only strong enough to overcome friction, pilot can overpower it for flare or manouvre - in practice it could just turn off once collective has been auto auto'd.
Keep system simple to start with, so just have system drop collective when buzzer sounds then disconnect. Later incarnations could take a signal from rotor Nr needle (I imagine it is a tacho signal), to trim for a specific Nr thus accounting for any cyclic movement to convert airspeed into Nr.
Once you get this system to work a phone call to Uncle Frank might get you a licence agreement. Then you start talks about including auto cyclic control as part of R44 SAS system.
BTW PM me if you want a resource in engineering community. I'm pretty busy, but interested.
EricFerret
Can't find the report but I did find this which mentions the wessex incident and a few others in the discussion about intervention delay times on page 4, the G-ASWI accident gets a mention on page 5.
http://www.flightsafety.org/hs/hs_mar_apr99.pdf#page=5
V.
Can't find the report but I did find this which mentions the wessex incident and a few others in the discussion about intervention delay times on page 4, the G-ASWI accident gets a mention on page 5.
http://www.flightsafety.org/hs/hs_mar_apr99.pdf#page=5
V.
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Looks like AAED concept being developed...
Folks routinely operating below HV curve will likely be grateful when Automatic Autorotation Entry Device is a standard fit...
Use RH mouse button to save or open linked PDF file:
http://www.systemstech.com/component...,15/Itemid,72/
Use RH mouse button to save or open linked PDF file:
http://www.systemstech.com/component...,15/Itemid,72/
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Thanks Graviman, VeeAny, Helocaptain... (TeT too.. )
Great feed back.
Stanley Hiller Igor Sikorsky and Larr Bell should have had this conversation about 1947!
The certain death of a slow pilot who does NOT get the collective down after engine failure in the climb, at gunslinger speed, is the equivalent of a Cherokee that suffers wing spar failure under the same circumstances.
Would the FAA or any other regulator certify such a deathtrap?
I was wrong of course to suggest a hydraulic linkage, much too slow. This came from an idea when I thought that Frank would fit a propeller - style governor to regulate RRPM.
The answer must be electronic, possibly a solenoid that collapses the linkage, along with a sharpish cyclic flare, maybe even an ignition cutout to resolve all doubt.
thekite
Stanley Hiller Igor Sikorsky and Larr Bell should have had this conversation about 1947!
The certain death of a slow pilot who does NOT get the collective down after engine failure in the climb, at gunslinger speed, is the equivalent of a Cherokee that suffers wing spar failure under the same circumstances.
Would the FAA or any other regulator certify such a deathtrap?
I was wrong of course to suggest a hydraulic linkage, much too slow. This came from an idea when I thought that Frank would fit a propeller - style governor to regulate RRPM.
The answer must be electronic, possibly a solenoid that collapses the linkage, along with a sharpish cyclic flare, maybe even an ignition cutout to resolve all doubt.
thekite
If you are going to use electronics to lower \ collapse collective the same unit could a. be sampling eng rpm and rotor rpm,
b. After eng cut, rotor rpm could be kept in green by same govener allowing pilot to concentrate on landing site and flair.
ahh well back to reality I suppose
b. After eng cut, rotor rpm could be kept in green by same govener allowing pilot to concentrate on landing site and flair.
ahh well back to reality I suppose
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500e, the beauty is that all these sensors are already present in all helicopters. You really can design a retrofit system.
thekite, agreed it's nuts to put this extra workload on the pilot in an emergency. For training system could just be turned off, like throttle govenor. Best of all below HV curve system will put you into auto before you realise there was a problem. A good pilot would effectively follow through on the collective.
The assumption is that in cruise pilot will be concentrating on cyclic, and near ground will be concentrating on collective. This means that by having the system weakly try to maintain Nr then in cruise pilot can pull back on cyclic to maintain height, and near ground can override collective to flare.
Not conviced about engine cutout though. A better system would be that AAED only becomes active if engine fails to meet demand, so that Nr droop occurs. This means pilot may be able to tease another hundred metres out of a dying engine to make that forrest clearing. The on/off alarm could be supplimented by a "engine failing to meet demand" warning. AAED may then remain inactive by pilot lowering collective.
A good system keeps the options open.
thekite, agreed it's nuts to put this extra workload on the pilot in an emergency. For training system could just be turned off, like throttle govenor. Best of all below HV curve system will put you into auto before you realise there was a problem. A good pilot would effectively follow through on the collective.
The assumption is that in cruise pilot will be concentrating on cyclic, and near ground will be concentrating on collective. This means that by having the system weakly try to maintain Nr then in cruise pilot can pull back on cyclic to maintain height, and near ground can override collective to flare.
Not conviced about engine cutout though. A better system would be that AAED only becomes active if engine fails to meet demand, so that Nr droop occurs. This means pilot may be able to tease another hundred metres out of a dying engine to make that forrest clearing. The on/off alarm could be supplimented by a "engine failing to meet demand" warning. AAED may then remain inactive by pilot lowering collective.
A good system keeps the options open.
Last edited by Graviman; 27th Aug 2007 at 12:02.
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You had better have a radalt limit switch variably interconnected to the relative airspeed on it as well.
The very last thing that one needs when cruising at any speed anywhere below 300'AGL is have some gremlin slam the collective down for you.
The very last thing that one needs when cruising at any speed anywhere below 300'AGL is have some gremlin slam the collective down for you.
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Great thinking
Yes we have a good train of thought about keeping that sucker going for a few seconds longer to make the clearing...
With existing piston engines, there is no advantage. Lycoming engines will instantly shutdown and the overunning clutch will cut it loose.
But with turbines, there could be an advantage. Allison 250s, (sorry Rolls Royce...) are damn difficult to kill. I know of a geologist who used an axe to chop the fuel lines on a JetRanger after a crash, with all the geos out, but the pilot still unconscious in the churning wreckage. (all those years at university....!)
So then why cut the engine out. You just might make that clearing. Right now my shoulder aches, as a result of that day 12 years ago when I hit the top of the treeeeee But I digress.
Unlike a piston engine, a turbine will hang damn well in there, if the fuel is there. And even though we have gone into AutoDump ( what was that great acronim; AAED?), maybe we could just keep it delivering a few seconds longer. And it just might save your life.
Future piston engines? Frankly I doubt it. They are still going to quit when they quit.
But with turbines, even though we have just entered autodump or AAED, if we have the option of milking up a little collective, and even though the revs are so low we can't look the tacho in the eye.. (you guys take over. My shoulder hurts. You have control.)
thekite
With existing piston engines, there is no advantage. Lycoming engines will instantly shutdown and the overunning clutch will cut it loose.
But with turbines, there could be an advantage. Allison 250s, (sorry Rolls Royce...) are damn difficult to kill. I know of a geologist who used an axe to chop the fuel lines on a JetRanger after a crash, with all the geos out, but the pilot still unconscious in the churning wreckage. (all those years at university....!)
So then why cut the engine out. You just might make that clearing. Right now my shoulder aches, as a result of that day 12 years ago when I hit the top of the treeeeee But I digress.
Unlike a piston engine, a turbine will hang damn well in there, if the fuel is there. And even though we have gone into AutoDump ( what was that great acronim; AAED?), maybe we could just keep it delivering a few seconds longer. And it just might save your life.
Future piston engines? Frankly I doubt it. They are still going to quit when they quit.
But with turbines, even though we have just entered autodump or AAED, if we have the option of milking up a little collective, and even though the revs are so low we can't look the tacho in the eye.. (you guys take over. My shoulder hurts. You have control.)
thekite
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TeT, welcome!
You are right of course. But we would have to have a means of overiding all of this stuff. Principle 1. the pilot in command must remain the Pilot in Command must always remain the Pilot in Command!! ( thank you Mae West)
The new trick for we instructural types would be to teach when to
intervene with the machine and when to stay the **** away! And just fly the new regime.
(On another note, I believe that you and I may share a postcode. Show me yours and I'll show your mine)
thekite
The new trick for we instructural types would be to teach when to
intervene with the machine and when to stay the **** away! And just fly the new regime.
(On another note, I believe that you and I may share a postcode. Show me yours and I'll show your mine)
thekite