R22 Engine and Rotor RPM Overspeed(past red line) - Help!
Join Date: Apr 2007
Location: Uk
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
Good call Sir HC, stick with them.
This is what they pay astronomical insurance rates for, it shouldn't cost them too much.
This happens all the time, nice bit of cash flow for the local MO's and more importantly the manufacturer who could so easily fix this defect in their product but choose not to....I wonder why
This is what they pay astronomical insurance rates for, it shouldn't cost them too much.
This happens all the time, nice bit of cash flow for the local MO's and more importantly the manufacturer who could so easily fix this defect in their product but choose not to....I wonder why
Is there a way to view the R22 maintenance manual online at no charge?
Join Date: Sep 2007
Location: On the Rump of Pendle Hill Lancashi
Posts: 614
Likes: 0
Received 0 Likes
on
0 Posts
Ifresh,
Well done for reporting it, I once SFH a R22 that had been used to demo Autos to power recovery , only the rotor went wild and oversped nearly everything it could, the young new FI didnt write it up and I was allocated that R22.. 2 hours later, I covered it well about eight years ago on Rotorheads, but the effects were frightening , No left turn ability my sixteen stone(then) weight could not control the stick and I was unable to land immediate due houses and buildings, wont bore you with the details but I have never flown any Robinson products since, I lost my trust in their ability!
Peter RB
Lancashire
Well done for reporting it, I once SFH a R22 that had been used to demo Autos to power recovery , only the rotor went wild and oversped nearly everything it could, the young new FI didnt write it up and I was allocated that R22.. 2 hours later, I covered it well about eight years ago on Rotorheads, but the effects were frightening , No left turn ability my sixteen stone(then) weight could not control the stick and I was unable to land immediate due houses and buildings, wont bore you with the details but I have never flown any Robinson products since, I lost my trust in their ability!
Peter RB
Lancashire
Join Date: Jan 2008
Location: lancs.UK
Age: 77
Posts: 1,191
Likes: 0
Received 0 Likes
on
0 Posts
For very little additional manufacturing costs, the relevant gauges could be made to incorporate a second, "marker" needle.
In operation,the main needle pushes the marker with it,leaving the marker behind when it falls back.....without an external reset-knob, a clear , "at -a- glance" record is there, of the highest reading given by that instrument.
Same system can be incorporated in the software of "glass" instrumentation.
I think it shows low moral integrity on the part of airframe-manufacturers ,that such fundamental safety-features are omitted.
legislation alone, will not deter the immoral, amoral or dishonest from walking away from a potential deathtrap, or selling it on.
In operation,the main needle pushes the marker with it,leaving the marker behind when it falls back.....without an external reset-knob, a clear , "at -a- glance" record is there, of the highest reading given by that instrument.
Same system can be incorporated in the software of "glass" instrumentation.
I think it shows low moral integrity on the part of airframe-manufacturers ,that such fundamental safety-features are omitted.
legislation alone, will not deter the immoral, amoral or dishonest from walking away from a potential deathtrap, or selling it on.
Join Date: Apr 1998
Location: Mesopotamos
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
The little red mark in the OP's pic is not in the red so there's nothing to worry about 
- if the needle can actually go that far off the scale it makes you think was Frank saving weight by reducing the red paint for the overspeed band?
As a very low solo hour pre-govenor R22 stude coming from a H300, I did overspeed the engine once. During the take-off phase I put the engine needle at the top of the green arc when light on the skids. As I lifted off the correlator pushed the engine needle one third into the red arc, I overreacted with the throttle correction and found myself doing a soft auto into the ground. I shut down and reported the incident. I think both instructor and owner were laughing when I told them how far and how long, but hey I was still very wet behind the ears. I got back in the machine and this time paid more attention to the very narrow power band of the R22 unlike the 300.
- if the needle can actually go that far off the scale it makes you think was Frank saving weight by reducing the red paint for the overspeed band?As a very low solo hour pre-govenor R22 stude coming from a H300, I did overspeed the engine once. During the take-off phase I put the engine needle at the top of the green arc when light on the skids. As I lifted off the correlator pushed the engine needle one third into the red arc, I overreacted with the throttle correction and found myself doing a soft auto into the ground. I shut down and reported the incident. I think both instructor and owner were laughing when I told them how far and how long, but hey I was still very wet behind the ears. I got back in the machine and this time paid more attention to the very narrow power band of the R22 unlike the 300.
regarding throttle control, governor:
Due to being rather fat, training in an R22 was never an option for me. So when my buddy and I signed up with the other school near by, I asked if their 300Cs were equipped with governors, "like them nice R22s".
Owner, master FI, head of you name it, looked at me sporting a very evil grin and said "nope. And if they did, I'd take them out myself, as I'll make sure, you guys will learn to control that bugger manually".
Turns out that 300C correlator mechanism only does a mediocre job, and "watch your rpms", "check engine speed", "no, we don't take of doing 2900" were among the most common lines of communication, rounded off by the headmaster's claim he won't need that fancy rpm meter at all as he can tell the engine speed by ear.
Now both me and my buddy are used to keeping the rpms not only in the green but inside specific parts of the green arc at will.
What astonishes me is that initially we'd quite frequently accidentally fly
with 100 rpms past redline for a couple of secs and no one would care, ground it or tear it down. And to me that very FTO is quite meticulous in regard to maintaining their source of revenue.
So why is passing red line in an R22 such an issue?
Is the 320 so much more overrevv sensitive than the 360?
Due to being rather fat, training in an R22 was never an option for me. So when my buddy and I signed up with the other school near by, I asked if their 300Cs were equipped with governors, "like them nice R22s".
Owner, master FI, head of you name it, looked at me sporting a very evil grin and said "nope. And if they did, I'd take them out myself, as I'll make sure, you guys will learn to control that bugger manually".
Turns out that 300C correlator mechanism only does a mediocre job, and "watch your rpms", "check engine speed", "no, we don't take of doing 2900" were among the most common lines of communication, rounded off by the headmaster's claim he won't need that fancy rpm meter at all as he can tell the engine speed by ear.
Now both me and my buddy are used to keeping the rpms not only in the green but inside specific parts of the green arc at will.
What astonishes me is that initially we'd quite frequently accidentally fly
with 100 rpms past redline for a couple of secs and no one would care, ground it or tear it down. And to me that very FTO is quite meticulous in regard to maintaining their source of revenue.
So why is passing red line in an R22 such an issue?
Is the 320 so much more overrevv sensitive than the 360?
Join Date: Jul 2010
Location: Wrong Town
Posts: 211
Likes: 0
Received 0 Likes
on
0 Posts
I'm not sure if they are that sensitive but when I've dealt with an oversped R44 and sent the engine away for repair there was obvious signs of damage due to the overspeed. Helicopter engines are never meant to be oversped at all. Lycoming is very clear on that in there maintenance data.
Join Date: Oct 2007
Location: Close to the hangar, UK.
Posts: 162
Likes: 0
Received 0 Likes
on
0 Posts
The manufacturers will (obviously) define the tolerances for their engines - but it seems strange to me that in the 22 & 44 you operate an engine within a few percent of it lunching itself and needing a complete examination.
Now an open throttle start from cold I can see causing a lot of potential damage, but a 6% overspeed on an auto re-join?
Given these engines are chosen for their reliability, are then de-rated but (apparently) run within a few percent of imminent destruction seems a bit strange.
But what would I know. I only allowed to change the oil with written instructions...
Now an open throttle start from cold I can see causing a lot of potential damage, but a 6% overspeed on an auto re-join?
Given these engines are chosen for their reliability, are then de-rated but (apparently) run within a few percent of imminent destruction seems a bit strange.
But what would I know. I only allowed to change the oil with written instructions...
I'm not sure if they are that sensitive but when I've dealt with an oversped R44 and sent the engine away for repair there was obvious signs of damage due to the overspeed. Helicopter engines are never meant to be oversped at all. Lycoming is very clear on that in there maintenance data.
On the R44, it's the other way around. The spindle bearings must be stronger, but that 540 engine does not like overspeeds at all.
Personally I'm right on firebird_uk's side on that topic. But if overspeed is that big a safety issue, especially when not properly logged and treated, why not prevent it by shorting the ignition at 105% rpm?
Every modern offroad racing motorcycle has that, the YZ400 kills ignition at 11.000rpm my wr450 at 10.400 rpms. You can fall off the bike in the woods and rest assured that the stuck throttle won't ruin your engine, BTDT. Going WFO in 3rd will feel as if one hits a wall when the limit is reached. It would be an addon feature, electronically shorting the ignition, kind of "parallel to the main ign switch".
The S-300Cs offers an option to cut ignition at ">1700 + clutch_open" (I bet every FTO has that option in place, it drastically reduces engine-to-pulley shaft repairs ) why not add another limit at ~3300?
The thing I don't understand about Frank and his machines is why he skipped some very simple ways to make his machines as bulletproof as the old 300C:
1 decent inertia rotor
2 fuel injection (how about IO-320-B1A?
)
3 rev limiters
4 bladder tanks
Mind you, 2) is the very reason, that the Cabri is not very attractive in my eyes, in 21st century there ought be no place for carburetors in aircrafts, at least in new designs.
yust my 2cts
Every modern offroad racing motorcycle has that, the YZ400 kills ignition at 11.000rpm my wr450 at 10.400 rpms. You can fall off the bike in the woods and rest assured that the stuck throttle won't ruin your engine, BTDT. Going WFO in 3rd will feel as if one hits a wall when the limit is reached. It would be an addon feature, electronically shorting the ignition, kind of "parallel to the main ign switch".
The S-300Cs offers an option to cut ignition at ">1700 + clutch_open" (I bet every FTO has that option in place, it drastically reduces engine-to-pulley shaft repairs
) why not add another limit at ~3300?The thing I don't understand about Frank and his machines is why he skipped some very simple ways to make his machines as bulletproof as the old 300C:
1 decent inertia rotor
2 fuel injection (how about IO-320-B1A?
)3 rev limiters
4 bladder tanks
Mind you, 2) is the very reason, that the Cabri is not very attractive in my eyes, in 21st century there ought be no place for carburetors in aircrafts, at least in new designs.
yust my 2cts
Last edited by Reely340; 11th Oct 2013 at 07:05.
Join Date: Jul 2010
Location: Wrong Town
Posts: 211
Likes: 0
Received 0 Likes
on
0 Posts
http://www.lycoming.com/Portals/0/te...0Overspeed.pdf
Lycoming are very clear in this service bulletin and it is highlighted.
"However, for rotary wing aircraft (helicopters), no momentary overspeed is
allowed and inspection and maintenance must be done as per this Service Bulletin."
Unlike planes helicopters do not have a fly wheel so any overspeed can lead to sharp torque increases that would be damped out by a propeller.
Lycoming are very clear in this service bulletin and it is highlighted.
"However, for rotary wing aircraft (helicopters), no momentary overspeed is
allowed and inspection and maintenance must be done as per this Service Bulletin."
Unlike planes helicopters do not have a fly wheel so any overspeed can lead to sharp torque increases that would be damped out by a propeller.
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,576
Received 430 Likes
on
227 Posts
Unlike planes helicopters do not have a fly wheel so any overspeed can lead to sharp torque increases that would be damped out by a propeller.
I'd have thought that over-speeding the engine would not cause a sharp increase in torque, rather the opposite (Power = Torque x RPM).
The service bulletin refers to the likelihood of broken piston rings and/or valve gear, caused by the the rotational speed and loss of control of inertial forces, rather than an over-torque.
The small rpm margin allowed (none for helicopters!) does suggest that the engine is working at the limit of reliability at the best of times.
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,576
Received 430 Likes
on
227 Posts
That's why I fly turbines - and two at once if three aren't available. 
Join Date: Jul 2010
Location: Wrong Town
Posts: 211
Likes: 0
Received 0 Likes
on
0 Posts
The main rotor blades in nearly every small helicopter are belt driven and there is no direct coupling to the engine and the blades do not act as a fly wheel would or as in fact a propeller that is directly coupled does.
I think one of the air safety magazines caused a bit of a stir last year when they suggested you could check which mag was not working whilst flying by switching to right and then left. If you do this in a small piston engines helicopter with one mag working there is a very good chance the engine will just cut out. In a plane that would be unlikely as the propeller would keep it turning. Feel free to try it out.
I think one of the air safety magazines caused a bit of a stir last year when they suggested you could check which mag was not working whilst flying by switching to right and then left. If you do this in a small piston engines helicopter with one mag working there is a very good chance the engine will just cut out. In a plane that would be unlikely as the propeller would keep it turning. Feel free to try it out.
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,576
Received 430 Likes
on
227 Posts
FSX, I'm well aware of the differences between fixed wing and rotary wing power plants and transmission systems. I stick by what I wrote. In the case of a piston engine overspeed, it's not excessive torque that would cause the damage to the engine itself. The service bulletin backs this up. Valve gear and piston rings do not get broken by over-torqueing, but by over-speeding. Balance shaft bushes are damaged by excessive inertial forces, not by torque.
If an over-torque occurred, it would result in a transmission or main rotor inspection, and that isn't the problem here.
As far as switching off the good mag of a helicopter piston engine in the case of the other being possibly faulty, no thankyou. I'm not in the habit of trying stuff likely to kill me, especially as this means the left hand was away from the collective to operate the magneto switch. I read that bulletin, too, btw. The difference is that a helicopter transmission has an over-run clutch / freewheel device and of course an aeroplane engine has the prop bolted directly on the crank (at least in most cases, there are some exceptions which are geared/belt driven). Yes, switching off the ignition would probably result in a sudden engine stoppage because nothing external would be driving the crankshaft round.
But that problem is about as far from an engine over-speed as one could get so I don't see the relevance...
If an over-torque occurred, it would result in a transmission or main rotor inspection, and that isn't the problem here.
As far as switching off the good mag of a helicopter piston engine in the case of the other being possibly faulty, no thankyou. I'm not in the habit of trying stuff likely to kill me, especially as this means the left hand was away from the collective to operate the magneto switch. I read that bulletin, too, btw. The difference is that a helicopter transmission has an over-run clutch / freewheel device and of course an aeroplane engine has the prop bolted directly on the crank (at least in most cases, there are some exceptions which are geared/belt driven). Yes, switching off the ignition would probably result in a sudden engine stoppage because nothing external would be driving the crankshaft round.
But that problem is about as far from an engine over-speed as one could get so I don't see the relevance...
