R22 Corner
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Heavier blades don't have more torque, just more inertia. The tail rotor won't be affected at all. They will spin up and slow down at a slower rate however.
What are they going to make stainless? The leading edge is already stainless and the skin is aluminum hence the corrosion problem. The R-44 has stainless skin that is much thinner and easily damaged.
What are they going to make stainless? The leading edge is already stainless and the skin is aluminum hence the corrosion problem. The R-44 has stainless skin that is much thinner and easily damaged.
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Has anyone any ideas as to why Enstrom blades do not seem to suffer the same problems as Robbie blades and are unlifed. 20+ year old servicable blades are not uncommon. If it comes down to a lighter design then surely this is one area where ecomomy of cost/weight is not prudent
Bugsmasherdriverandjediknite
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CJ Eliassen, mate, I hate to be picky, but you either need to learn to read or need to do another physics course. If the blades have more enertia, then surely they will require more torque to turn them.......... thus requiring more tail rotor to stop machine from spinning about the place. I may only be a pilot but I did learn a little bit about them before they let me lose on them. 
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Tim Tucker (at the Airlie Beach Safety Course) said the new blades had stainless steel skin. All else was the same and if I recall correctly he said the weight was the same. The problem it leads to is that the skin has to be thinner to allow for the weight factor.
The skin will be more fragile. Even th R44 skin is surprizingly fragile. They had a section of blade at the course and the lecturer gave it a sharp tap with his knuckle which left a dent easily visibly in the surface.
So it will be a case of gain something and lose something else.
The skin will be more fragile. Even th R44 skin is surprizingly fragile. They had a section of blade at the course and the lecturer gave it a sharp tap with his knuckle which left a dent easily visibly in the surface.
So it will be a case of gain something and lose something else.
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They had a section of blade at the course and the lecturer gave it a sharp tap with his knuckle which left a dent easily visibly in the surface.
Sounds about as usefull as an ashtray on a motorbike.
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CJ Eliassen, mate, I hate to be picky, but you either need to learn to read or need to do another physics course. If the blades have more enertia, then surely they will require more torque to turn them.......... thus requiring more tail rotor to stop machine from spinning about the place. I may only be a pilot but I did learn a little bit about them before they let me lose on them.
Take a spinning disc that weighs 2000 pounds and another that weighs 20 pounds and put them in space. You spin both up to the same constant RPM the same as a helicopter. Which one requires more torque to maintain the same speed? They both require 0 torque because they will spin forever without any resistance. Its not the weight you are applying torque to over come, its the parasitic drag and the induced drag from the lift produced. The exact same amount of torque is applied to a heavy set of blades as a light set of the same design.
Acceleration and deceleration of the blades is the only time torque will effect the speed of the blades. So, heavier blades will spin up slower than lighter blades with the same torque applied.
Tell me how that physics course goes for you.
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The fact is that the disc is continually loading and unloading to some degree and therefore accelerating and decelerating constanly.
Because it takes more time for heavier blades to spin up, if you lose rpm, (and we can't afford that), you have to use more power to control them. Frank and all engineers know that that's why they apparently haven't increased the weight of the new ones.
Harder to lose rpm but much harder, (power), to get it back.
It's not an ideal world, unfortunately.
Because it takes more time for heavier blades to spin up, if you lose rpm, (and we can't afford that), you have to use more power to control them. Frank and all engineers know that that's why they apparently haven't increased the weight of the new ones.
Harder to lose rpm but much harder, (power), to get it back.
It's not an ideal world, unfortunately.
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I have done some pretty agressive maneuvers int he R-22 and R-44 and the RPM never strayed more than one percent. There is plenty of torque from the engine to maintain the RPM even if the blades where heavier. In fact, if they were heavier, they would stray less than they do now since the inertia in the blades would allow more time for the engine to increase or decrease in power.
So no, heavier blades DO NOT require more torque or power from the engine.
I forgot to add that the reason they don't make the blades heavier is because it would be a waste of useful load. Why make them heavier when the current blades work just fine?
So no, heavier blades DO NOT require more torque or power from the engine.
I forgot to add that the reason they don't make the blades heavier is because it would be a waste of useful load. Why make them heavier when the current blades work just fine?
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I'm working on the same line of thought as Deeper.
Might have to enroll in that physics course yet.
I would have thought that the blades or disk is what was supporting the airframe, and then therefore, had no apparent weight, therefore, not having any effect on usefull empty weight.
Might have to enroll in that physics course yet.
I would have thought that the blades or disk is what was supporting the airframe, and then therefore, had no apparent weight, therefore, not having any effect on usefull empty weight.
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I suggest you might want to think about a private pilot course here in the states. We teach pilots a few things about helicopters before letting them loose.
Remember this quote?
"I may only be a pilot but I did learn a little bit about them before they let me lose on them."
Or did you actually mean lose? LOL
The weight of the blades is included in an aircrafts empty weight. You increase the weight of the blades, you lose useful load. The only time heavier blade will require more torque is when you increase the grossweight of the helicopter thereby increasing the lift and drag produced. But at 2500 pounds, the torque needed to maintain RPM is exactly the same with light blades or heavy blades with identical airfoils.
And as for the tailrotor, the Robinson tailrotors are the most efficient there are. You can pull 100% torque from the engine and the tail rotor can easily compensate. I would bet that every instructor here has pulled in more than the limit manifold pressure on an R-22 more than once with no LTE.
Remember this quote?
"I may only be a pilot but I did learn a little bit about them before they let me lose on them."
Or did you actually mean lose? LOL
The weight of the blades is included in an aircrafts empty weight. You increase the weight of the blades, you lose useful load. The only time heavier blade will require more torque is when you increase the grossweight of the helicopter thereby increasing the lift and drag produced. But at 2500 pounds, the torque needed to maintain RPM is exactly the same with light blades or heavy blades with identical airfoils.
And as for the tailrotor, the Robinson tailrotors are the most efficient there are. You can pull 100% torque from the engine and the tail rotor can easily compensate. I would bet that every instructor here has pulled in more than the limit manifold pressure on an R-22 more than once with no LTE.
Bugsmasherdriverandjediknite
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kinda dopey then I reckon. if ya pick something up with a crane, you don't weigh the crane.
lose, was a fruidian slip wasn't it.
I'm still not talking about maintaining the RRPM in the perfect world but one where the rotor is affected by outside stuff, like turbulence and control inputs. otherwise it wouldn't require anything to keep it going, would it?. some thing to do with newton?
I still cant except that a heavier rotor wouldnt require more torque to run............ otherwise they would stick huey rotors on it.
as for the tail rotor....... well yes I agree, they are the best ones about, but they will have a limit somewherealong the line. stick a set of 22 TR blades on a 44 and it would be amply demonstrated.
PS, I cant spell...so what? they didn't cover spelling when I did me ATPL subjects or CPL (A) or CPL(H).
Gotta be something in that.
lose, was a fruidian slip wasn't it.
I'm still not talking about maintaining the RRPM in the perfect world but one where the rotor is affected by outside stuff, like turbulence and control inputs. otherwise it wouldn't require anything to keep it going, would it?. some thing to do with newton?
I still cant except that a heavier rotor wouldnt require more torque to run............ otherwise they would stick huey rotors on it.
as for the tail rotor....... well yes I agree, they are the best ones about, but they will have a limit somewherealong the line. stick a set of 22 TR blades on a 44 and it would be amply demonstrated.
PS, I cant spell...so what? they didn't cover spelling when I did me ATPL subjects or CPL (A) or CPL(H).
Gotta be something in that.
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They don't stick huey blades on them because they are too heavy and you would lose useful load. The current blades are fine and the R-44 autorotation characterisitcs are excellent.
They did increase the weight of the R-22 blades to help autorotation characteristics. However, they didn't change anything to the tail rotor or the power output limitations, and the useful load was reduced.
As a mechanic I can assure you I do not remove the blades of any helicopter when I weigh them.
A crane is the lifting force. The blades are not the lifting force in a helicopter. Lift is the lifting force. The amount of lift produce must be equal and opposite to the weight of the entire aircraft including the blades in unaccelerated flight.
They did increase the weight of the R-22 blades to help autorotation characteristics. However, they didn't change anything to the tail rotor or the power output limitations, and the useful load was reduced.
As a mechanic I can assure you I do not remove the blades of any helicopter when I weigh them.
A crane is the lifting force. The blades are not the lifting force in a helicopter. Lift is the lifting force. The amount of lift produce must be equal and opposite to the weight of the entire aircraft including the blades in unaccelerated flight.
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R22 Blades
Can someone give me an opinion on why we seldom hear of Bell 47's, Hugh 269, Bell 206 etc that are also used by mustering companies, throw a main or tail rotor blade? Are R22 blades designed so that there is a much smaller margin or safety in them? Thanks.
Bugsmasherdriverandjediknite
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well......... I think we is having a different thought train here.
tour probly rite though, nevr did learn nuffin useful at flying skool.
I will think out my reply next time so its a bit more betterer to understand.......havnt mastered that art yet.
tour probly rite though, nevr did learn nuffin useful at flying skool.
I will think out my reply next time so its a bit more betterer to understand.......havnt mastered that art yet.
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the infuriating AD: 2004-06-52
The March 18, 2004 AD might just fall apart from illogic.
Supposedly, it's based on two instances of fatigue cracking, possibly from moisture penetration and corrosion. Fatigue cracking is a result of stress and number of cycles, right? But for most of the fleet's blades (-2's), the number of cycles is unchanged: 2200 hours. So the AD which purports to reduce fatigue cracking does not reduce the number of cycles on the blades. ?!? Say what?
But then the FAA (and Robinson) try to dazzle/hoodwink us, without even benefit of smoke and mirrors, and supposedly solve a fatigue-cycle crack by instituting a 10-year CALENDAR life limit! (New deal--previously the FAA had no requirement, and Robinson's 12-year-life was irregularly applied by the maintenance community.)
And there has never been, so far as I can discover, a single shred of evidence that any rotor blades have failed because of calendar age--for instance, by being bolted to a dormant R22. ("Dormant": for instance, one which accumulates 100 hours in 18 years).
Whatever committee wrote the AD is seriously out of contact with reality. They would have us believe they're trying to reduce fatigue cracking, but their "remedy" (for -2's) allows the same number of hours-in-service (2200), so the entire fleet's blades will ultimately be allowed the same number of fatigue cycles as before the AD. What do they think they're changing? Did the authors have any aviation background, or is this equal-opportunity-employment at its worst?
The maximum-calendar-life limit is absurd, unless they know something they're not telling us! Fatigue cycles, as we all know, do not accumulate while the helicopter is not flying. Calendar AGE of the blades has yet to be shown to be a cause of failure (anybody know of a study?). Even IF the fatigue cracking has a root cause in moisture, and even IF it were true that old-age-blades accumulate more moisture, they've ignored the 10%-40% (?) of the fleet that IS stored in humidity-controlled hangars.
One hopes that this AD will soon be revised. Radically. As is, it's an embarrassment to both the FAA and Robinson. Incredible! Preventing flight-induced fatigue cracking by scrapping blades because they've been sitting (unstressed, unflown) in the hangar too long? Absurd!
Supposedly, it's based on two instances of fatigue cracking, possibly from moisture penetration and corrosion. Fatigue cracking is a result of stress and number of cycles, right? But for most of the fleet's blades (-2's), the number of cycles is unchanged: 2200 hours. So the AD which purports to reduce fatigue cracking does not reduce the number of cycles on the blades. ?!? Say what?
But then the FAA (and Robinson) try to dazzle/hoodwink us, without even benefit of smoke and mirrors, and supposedly solve a fatigue-cycle crack by instituting a 10-year CALENDAR life limit! (New deal--previously the FAA had no requirement, and Robinson's 12-year-life was irregularly applied by the maintenance community.)
And there has never been, so far as I can discover, a single shred of evidence that any rotor blades have failed because of calendar age--for instance, by being bolted to a dormant R22. ("Dormant": for instance, one which accumulates 100 hours in 18 years).
Whatever committee wrote the AD is seriously out of contact with reality. They would have us believe they're trying to reduce fatigue cracking, but their "remedy" (for -2's) allows the same number of hours-in-service (2200), so the entire fleet's blades will ultimately be allowed the same number of fatigue cycles as before the AD. What do they think they're changing? Did the authors have any aviation background, or is this equal-opportunity-employment at its worst?
The maximum-calendar-life limit is absurd, unless they know something they're not telling us! Fatigue cycles, as we all know, do not accumulate while the helicopter is not flying. Calendar AGE of the blades has yet to be shown to be a cause of failure (anybody know of a study?). Even IF the fatigue cracking has a root cause in moisture, and even IF it were true that old-age-blades accumulate more moisture, they've ignored the 10%-40% (?) of the fleet that IS stored in humidity-controlled hangars.
One hopes that this AD will soon be revised. Radically. As is, it's an embarrassment to both the FAA and Robinson. Incredible! Preventing flight-induced fatigue cracking by scrapping blades because they've been sitting (unstressed, unflown) in the hangar too long? Absurd!
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PA42
Cant speak for Robbie blades but when I got my Enstrom (which lives outside) I was advised to keep the blades covered when not in use as environmental variables (sun, temperature variation,humdity?) cause deterioration in the bonding adhesives over time. The blade covers are reflective silver so I suspect exposure to sun may be the concern. The blades are painted white on top which keeps them cooler in full sunshine. Enstrom blades are lifed on condition and the usual failure is debonding. Not a study but advice given to me by an experienced owner.
Watching the blades flap about in last weeks gales also made me think that windy conditions could affect the blades. It was alarming enough to make me go out in pouring rain and put the tiedowns on!
Also unflown is not not unstressed. Droop forces are considerable and must be allowed for in the design of the blade. These forces are totally different to flying forces. Just think of the constant stress at the blade root - just where they fail- caused by the weight of the blade supported at one end. Try picking a blade up by one end! Was this stress made worse by adding tip weights?? Perhaps this is Robinsons problem.
Cant speak for Robbie blades but when I got my Enstrom (which lives outside) I was advised to keep the blades covered when not in use as environmental variables (sun, temperature variation,humdity?) cause deterioration in the bonding adhesives over time. The blade covers are reflective silver so I suspect exposure to sun may be the concern. The blades are painted white on top which keeps them cooler in full sunshine. Enstrom blades are lifed on condition and the usual failure is debonding. Not a study but advice given to me by an experienced owner.
Watching the blades flap about in last weeks gales also made me think that windy conditions could affect the blades. It was alarming enough to make me go out in pouring rain and put the tiedowns on!
Also unflown is not not unstressed. Droop forces are considerable and must be allowed for in the design of the blade. These forces are totally different to flying forces. Just think of the constant stress at the blade root - just where they fail- caused by the weight of the blade supported at one end. Try picking a blade up by one end! Was this stress made worse by adding tip weights?? Perhaps this is Robinsons problem.
Last edited by Gaseous; 25th Mar 2004 at 20:38.
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whimsical AD revision
Gaseous: hmmm, good thoughts.
As it happened, I had added a bladeshade to the tiedown array just a couple of weeks before the AD, so I am in sympathy with the potential (howsomever unpublished) possibility of solar-energy-cycles.
Droop stress is an interesting thought. (Perhaps explaining certain bodily reflexes which are abating as I grow older?) Thus far, I have seen no military or civilian RotorSlings for maintaining erect blades while parked; has anybody ever caught (or ducked) a failed blade resulting from multiple repetitive droop stress syndrome? Think of the marketing possibilities once the FAA and the public become hysterical over this new threat to airworthiness!
But onward. The revised version:
AD 2004-06-52, Rev. 1. All R22 blades must be retired at 2199 hours TIS, as the previous life limit (2200 hours) engendered serious risk of fatigue failure resulting from electronic shock during reconnection of the hobbs meter after several years of operation without functioning hobbs meter. Furthermore, all blades must be retired 1 (one) calendar year after initial installation (hey, if we're going to pick an arbitrary, unjustified number, let's err on the side of safety!) UNLESS a continuous photo album is maintained showing daily photos of each blade's weight supported by a suitable rotorshade/sling combination (Robinson P.N. 007.01, $25,000 FOB Torrance), in which case blades may be used indefinitely on condition.
Usefulness index of this AD: Zip. But I had fun. Was it good for you?
As it happened, I had added a bladeshade to the tiedown array just a couple of weeks before the AD, so I am in sympathy with the potential (howsomever unpublished) possibility of solar-energy-cycles.
Droop stress is an interesting thought. (Perhaps explaining certain bodily reflexes which are abating as I grow older?) Thus far, I have seen no military or civilian RotorSlings for maintaining erect blades while parked; has anybody ever caught (or ducked) a failed blade resulting from multiple repetitive droop stress syndrome? Think of the marketing possibilities once the FAA and the public become hysterical over this new threat to airworthiness!
But onward. The revised version:
AD 2004-06-52, Rev. 1. All R22 blades must be retired at 2199 hours TIS, as the previous life limit (2200 hours) engendered serious risk of fatigue failure resulting from electronic shock during reconnection of the hobbs meter after several years of operation without functioning hobbs meter. Furthermore, all blades must be retired 1 (one) calendar year after initial installation (hey, if we're going to pick an arbitrary, unjustified number, let's err on the side of safety!) UNLESS a continuous photo album is maintained showing daily photos of each blade's weight supported by a suitable rotorshade/sling combination (Robinson P.N. 007.01, $25,000 FOB Torrance), in which case blades may be used indefinitely on condition.
Usefulness index of this AD: Zip. But I had fun. Was it good for you?
Iconoclast
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Solar radiation
Solar radiation and temperature cycling can have an effect on rotor blades relative to bonding agents and sealants. It is possible that solar radiation can raise the temperature of metallic structure well in excess of 160-degrees F. One manufacturer of elastomeric elements used in rotor systems indicated that the total exposure to temperatures in excess of 160-degrees F is limited to one hour over the design life of the elastomeric element. Exceeding this limit will cut the life expectancy (MTBF) by 50%.
In Iran we experienced air temperatures of 113-degrees F. The ground temperature was 168-degrees F and the temperature inside the cabins was 180-degrees which was the limit of our thermometer. It got so hot inside that it cooked the black boxes and some of the instruments.
In Iran we experienced air temperatures of 113-degrees F. The ground temperature was 168-degrees F and the temperature inside the cabins was 180-degrees which was the limit of our thermometer. It got so hot inside that it cooked the black boxes and some of the instruments.
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Lu: yes, yes, don't stop now, keep going!
OK, so far so good, now you've got me panting for more,
have any blade failures been blamed on solar radiation?
I grant the possibility of delamination & other ills, but have yet to see any rotors covered with sunshades (hangaring being a different phenomenon since the presumed motivations for hangaring can be so diverse . . .).
The f/w crowd occasionally cover their wings just to save the paint (or, more $$$$, fabric, when present). But wouldn't we see Robinson issuing safety notices against leaving blades exposed to sunlight if there was a safety risk from delamination?
(Or, conversely, if sunburned 12 year blades are experiencing "fatigue," can we believe that reducing sunburn below 10.001 years makes us safe from that fatigue? Sorry, brain fatigue from trying to devine the Robinson mythos.)
have any blade failures been blamed on solar radiation?
I grant the possibility of delamination & other ills, but have yet to see any rotors covered with sunshades (hangaring being a different phenomenon since the presumed motivations for hangaring can be so diverse . . .).
The f/w crowd occasionally cover their wings just to save the paint (or, more $$$$, fabric, when present). But wouldn't we see Robinson issuing safety notices against leaving blades exposed to sunlight if there was a safety risk from delamination?
(Or, conversely, if sunburned 12 year blades are experiencing "fatigue," can we believe that reducing sunburn below 10.001 years makes us safe from that fatigue? Sorry, brain fatigue from trying to devine the Robinson mythos.)