Robinson R44
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I know of a Bell 407 that did a loop and roll at an air show in South Africa.
See http://hagar.up.ac.za/christo/Bell407Loop.wmv
Far as I know, the aircraft has been grounded ever since
See http://hagar.up.ac.za/christo/Bell407Loop.wmv
Far as I know, the aircraft has been grounded ever since
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Having planned the engineering tests for and then flown the rolls loops and splt S maneuvers for several helicopters, I can assure you that anyone who tries these things in a teetering rotor helo is suicidal.
The margins between "success" and breakup of the aircraft is near nil, anything out of the ordinary will lead to loss of control, rotor contact with the fuselage and catastrophe.
That 407 shown maneuvering is a far piece better in rotor control power than a Robinson, but still considerably less capable than a Boelkow. The roll to the left invokes a strong yaw at the 270 degree point (I have seen thast in other helos, too) and that is what got away from the pilot in the clip.
Most helo aerobatic maneuvers are good for bar talk, but of little use in operations.
The margins between "success" and breakup of the aircraft is near nil, anything out of the ordinary will lead to loss of control, rotor contact with the fuselage and catastrophe.
That 407 shown maneuvering is a far piece better in rotor control power than a Robinson, but still considerably less capable than a Boelkow. The roll to the left invokes a strong yaw at the 270 degree point (I have seen thast in other helos, too) and that is what got away from the pilot in the clip.
Most helo aerobatic maneuvers are good for bar talk, but of little use in operations.
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R44 in Turbulence
Looking for comments on being caught in uncomfortable turbulence in the R44 and/or B206.
The other day I had to do a photo shoot and survey in an R44. I collected the pax from a city airfield situated in a bowl bordered around the South to NW by a high ridge, rising to 1000' above the airfield. Wind at the airfield was NW steady 6 knots. As I climbed through 1000' AGL to get over the ridge, and still 2 miles out from it, I suddenly found myself in severe turbulence. Glancing at the GPS I had 35Kts groundspeed, with approx 80Kts indicated.
There was no prior indication of the strong wind coming over the ridge, and Met had given a 10 to 15kt N to NW forecast for the day.
We bounced around horrifically while still over the city with a couple of miles to go to get clear of the built up area.
I slowed to 65 to 70Kts, climbed and eventually cleared the ridge.
Had to return to the airfield after a couple of hours to refuel and change pax, and ATC had me route from the West to the airfield. This time I had to descend through the turbulence with the wind from behind - no other way to get to the ground or the airfield.
Also very unpleasant!
The flight manual says don't fly in severe turbulence - but what about during the time where you are trying to get out of it when caught unawares or where the task at hand means flying in uncomfortable turbulence for a while.
What are the margins for safety or how great is the danger (before possible mast bumping or overstressing etc.) - especially with the wind from behind (as in for example taking the shortest route away from a built up area?)
I also had a similar experience recently flying the B206 in uncomfortable low level turbulence doing heli tours along a beachfront - wind tumbling off a coastal ridge and through high rise beachfront buildings!
Can anyone with regular experience of flying R44's or B206's in rough winds and turbulence comment on the safety of working in these conditions. The two bladed systems don't give a feeling of security!
Look forward to learning from some of your experiences ...
The other day I had to do a photo shoot and survey in an R44. I collected the pax from a city airfield situated in a bowl bordered around the South to NW by a high ridge, rising to 1000' above the airfield. Wind at the airfield was NW steady 6 knots. As I climbed through 1000' AGL to get over the ridge, and still 2 miles out from it, I suddenly found myself in severe turbulence. Glancing at the GPS I had 35Kts groundspeed, with approx 80Kts indicated.
There was no prior indication of the strong wind coming over the ridge, and Met had given a 10 to 15kt N to NW forecast for the day.
We bounced around horrifically while still over the city with a couple of miles to go to get clear of the built up area.
I slowed to 65 to 70Kts, climbed and eventually cleared the ridge.
Had to return to the airfield after a couple of hours to refuel and change pax, and ATC had me route from the West to the airfield. This time I had to descend through the turbulence with the wind from behind - no other way to get to the ground or the airfield.
Also very unpleasant!
The flight manual says don't fly in severe turbulence - but what about during the time where you are trying to get out of it when caught unawares or where the task at hand means flying in uncomfortable turbulence for a while.
What are the margins for safety or how great is the danger (before possible mast bumping or overstressing etc.) - especially with the wind from behind (as in for example taking the shortest route away from a built up area?)
I also had a similar experience recently flying the B206 in uncomfortable low level turbulence doing heli tours along a beachfront - wind tumbling off a coastal ridge and through high rise beachfront buildings!
Can anyone with regular experience of flying R44's or B206's in rough winds and turbulence comment on the safety of working in these conditions. The two bladed systems don't give a feeling of security!
Look forward to learning from some of your experiences ...
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Good post I fly the R44 alot and don't like taking it out when it's realy windy the R22 is better,as mast bumping and low G can be a kiler in the R44.You did the right thing in slowing down the only advice I could give is try and fly routes where your less likely to hit turbulance,and keep ATC informed of your reguirments.
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Turbulence and R44
Flying a lot in the south-east france (the mistral area), I have been a lot in very windy and gusty weather. Many times it happened that wind suddenly and unpredicted by Met goes to over 50 knts at low altitude (25 knots would be a calm day). I always managed to fly through it, but a few times I got kicked around so badly that I swore not to get caught in that again. In the case of a 'flying' 65 knots storm between Cannes and Marseille, I wisely back tracked even though ATC advised to continue., still landed with 45 knts.
What I learned
- avoid turbulence. Especially in mountainous areas you should be able to read where the vortices are, how big they will be etc. If you feel you can not do this, stay away. I do not know the particulars quoted by choppersafari, but 2 miles away can be far too little in some cases. Yesterday, departing from Le Castellet, gusting 35 knots I prefered to climb to FL55 (even though I was at MTOW) to be clear of St Baume mountain (3600ft), because to wind was coming from an unusual direction, so that I was not shure where the severe turbulence would be even though I think I know the area well.
- mountain flying techniques are very help full, look for laminar flow areas. These are sometimes also close to the ground, but for that you need to know the technique and the area well
- big vortices near mountain ridges need special attention. Sudden down drafts, especially if preceded by heavy updrafts, create low-G conditions. I always do a moderate flair into does : reducing speed from 105 to 80 and making shure the tail is low enough.
- if you are caught in an updraft and conditions permit, let it take you up. There will be a downdraft later in which you do not want to enter nose down at high speed.
- you also get sudden horizontal changes : for instance tail wind on top of a vortex projects you later in a windless area : this can create overspeed situations (going from 105 to 135 IAS in a few seconds) dangerous again if not anticipated
- if you are caught do not oversteer, reduce speed. This is particularly difficult, especially if you are badly kicked around and it appears the machine is not coming back by it self. Remember that the yawing creates side slip, in side slip you are supposed to steer the cyclic into the wind and not away from the wind which happens if you let your sence of equilibrium take over, exposing you to mast bumping. So it is perhaps better not to steer as indicated in the manual.
- avoid very low weights (for instance just pilot, with minimum fuel)
Delta3
What I learned
- avoid turbulence. Especially in mountainous areas you should be able to read where the vortices are, how big they will be etc. If you feel you can not do this, stay away. I do not know the particulars quoted by choppersafari, but 2 miles away can be far too little in some cases. Yesterday, departing from Le Castellet, gusting 35 knots I prefered to climb to FL55 (even though I was at MTOW) to be clear of St Baume mountain (3600ft), because to wind was coming from an unusual direction, so that I was not shure where the severe turbulence would be even though I think I know the area well.
- mountain flying techniques are very help full, look for laminar flow areas. These are sometimes also close to the ground, but for that you need to know the technique and the area well
- big vortices near mountain ridges need special attention. Sudden down drafts, especially if preceded by heavy updrafts, create low-G conditions. I always do a moderate flair into does : reducing speed from 105 to 80 and making shure the tail is low enough.
- if you are caught in an updraft and conditions permit, let it take you up. There will be a downdraft later in which you do not want to enter nose down at high speed.
- you also get sudden horizontal changes : for instance tail wind on top of a vortex projects you later in a windless area : this can create overspeed situations (going from 105 to 135 IAS in a few seconds) dangerous again if not anticipated
- if you are caught do not oversteer, reduce speed. This is particularly difficult, especially if you are badly kicked around and it appears the machine is not coming back by it self. Remember that the yawing creates side slip, in side slip you are supposed to steer the cyclic into the wind and not away from the wind which happens if you let your sence of equilibrium take over, exposing you to mast bumping. So it is perhaps better not to steer as indicated in the manual.
- avoid very low weights (for instance just pilot, with minimum fuel)
Delta3
Last edited by delta3; 3rd Apr 2005 at 10:50.
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More Winds and Turbulence ...
Outstanding replies – always good to learn from others experience – thanks guys.
On a similar note, I got caught in a ‘south westerly buster’ a little while ago along our south coast, again in an R44 and this time while instructing a student pilot on a cross country flight.
Fortunately I took control and slowed to 65Kts as we went under the cloud at 800’ AGL (cloud base was approx 1500’ – a churning angry mass of grey black turbulent cloud underneath which only became evident approx half a mile out from it).
I have photos which I could post later – scary!
As we hit the microburst IAS went instantly from 65Kts to 125Kts, and we were thrown around violently for a few seconds. A terrifying initial experience, and then had to sit in 45Kt gusting headwind for nearly half and hour trying to get to the airfield. No chance of landing in those conditions along the coast on route and sweated it out, eventually getting back to the airfield safely – just had to be gentle with the aircraft and ride with the turbulence as much as possible, coaxing the aircraft through it - lessons learned again!
Delta3 – You have obviously been in some severe conditions fairly regularly – thanks for the excellent practical info, and good to see you mention “…I swore not to get caught in that again…” – It never feels safe in the B206 or R44 with their teetering head systems in those conditions – and yet it is easy to find yourself caught there unawares if you don’t know what to look for, or are just in the wrong place at the wrong time.
Thanks for the good practical advice and informative posts …
On a similar note, I got caught in a ‘south westerly buster’ a little while ago along our south coast, again in an R44 and this time while instructing a student pilot on a cross country flight.
Fortunately I took control and slowed to 65Kts as we went under the cloud at 800’ AGL (cloud base was approx 1500’ – a churning angry mass of grey black turbulent cloud underneath which only became evident approx half a mile out from it).
I have photos which I could post later – scary!
As we hit the microburst IAS went instantly from 65Kts to 125Kts, and we were thrown around violently for a few seconds. A terrifying initial experience, and then had to sit in 45Kt gusting headwind for nearly half and hour trying to get to the airfield. No chance of landing in those conditions along the coast on route and sweated it out, eventually getting back to the airfield safely – just had to be gentle with the aircraft and ride with the turbulence as much as possible, coaxing the aircraft through it - lessons learned again!
Delta3 – You have obviously been in some severe conditions fairly regularly – thanks for the excellent practical info, and good to see you mention “…I swore not to get caught in that again…” – It never feels safe in the B206 or R44 with their teetering head systems in those conditions – and yet it is easy to find yourself caught there unawares if you don’t know what to look for, or are just in the wrong place at the wrong time.
Thanks for the good practical advice and informative posts …
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blue mountains turbulence
seem to recall a tale (thought i'd read it here, but couldn't locate any threads on it) of someone in a R44 coming back across the Blue Mountains in severe turbulence, when he finally got back to Bankstown it was discovered that the nylon 'pads' on the mast had been creased (& i think cracked), pretty sure it was grabbed by heliflite & sent back to 'the States' for examination, as no one had ever seen one (mast bump in a Robby) that hadn't ended in catastrophe. 
lucky fellow
there may be someone lurking in the forums that might be able to confirm &/or clarify the details as i don't have any (it was a 2nd hand story).
lucky fellow
there may be someone lurking in the forums that might be able to confirm &/or clarify the details as i don't have any (it was a 2nd hand story).
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Mast Bumping ...
I remember reading of a pilot telling how an instructor demonstrated a low G pushover in an R22 to him (against common sense and the FM!) - apparently there was a loud thump and bang as he recovered from the attitude changes - the instructor continued the flight saying no worries, all was fine ...
On landing an inspection revealed a crease in the mast [might have some details wrong - I will look through my stuff and see if I can find the printout - I seem to recall it being from one of these forums ...]
Has anyone out there had close calls with mast bumping in 22, 44 or 206's, and survived!?
I'm interested to know how violent the pitch and roll is and how much chance/time there is to load the disc again while it is rolling etc. - This could be a reality when caught in turbulence or updraught/downdraught windsheer ...
Would it help to 'ride with the right roll' while loading the disc with aft cyclic, or is the onset too quick and violent for this reaction?
[Obviously the 'intinctive' reaction would be to counter the roll with opposite cyclic, which accentuates the problem and accelerates the bumping potential - and the instinct will be more quickly applied with the speed of the onset of roll etc. especially if caught unawares! - and you want to be able to go against instinct to survive.]
On landing an inspection revealed a crease in the mast [might have some details wrong - I will look through my stuff and see if I can find the printout - I seem to recall it being from one of these forums ...]
Has anyone out there had close calls with mast bumping in 22, 44 or 206's, and survived!?
I'm interested to know how violent the pitch and roll is and how much chance/time there is to load the disc again while it is rolling etc. - This could be a reality when caught in turbulence or updraught/downdraught windsheer ...
Would it help to 'ride with the right roll' while loading the disc with aft cyclic, or is the onset too quick and violent for this reaction?
[Obviously the 'intinctive' reaction would be to counter the roll with opposite cyclic, which accentuates the problem and accelerates the bumping potential - and the instinct will be more quickly applied with the speed of the onset of roll etc. especially if caught unawares! - and you want to be able to go against instinct to survive.]
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From Safety Notice SN-11 in the R22 POH:
... if you do have a feeling of weightlessness dueing a maneuver, gently bring the cyclic aft to regain main rotor thrust before (underlined in POH) applying lateral cyclic.
Ride that roll until the rotor disc is re-loaded!
... if you do have a feeling of weightlessness dueing a maneuver, gently bring the cyclic aft to regain main rotor thrust before (underlined in POH) applying lateral cyclic.
Ride that roll until the rotor disc is re-loaded!
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Turbulence and Low G
to bladewashout
The theory is simple and correct, but in turbulent weather it does not come like "...a feeling of weightlessness during a maneuver...", YOU are not maneuvering, 'IT' is maneuvering, anticipation is key.
When I get the hitchy feeling I am about to hit an important down-draft, I start sort of a flare, that is well before I get weigthless.
By doing this
You have the tail down,
You anticipate the descent,
You (can) reduce some speed
You have the cyclic aft and can keep the disk loaded without big chocks.
Delta3
The theory is simple and correct, but in turbulent weather it does not come like "...a feeling of weightlessness during a maneuver...", YOU are not maneuvering, 'IT' is maneuvering, anticipation is key.
When I get the hitchy feeling I am about to hit an important down-draft, I start sort of a flare, that is well before I get weigthless.
By doing this
You have the tail down,
You anticipate the descent,
You (can) reduce some speed
You have the cyclic aft and can keep the disk loaded without big chocks.
Delta3
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R-44 Fuel Burn Question
I know there's a wealth of information on this board (as opposed to the chaff on some *others*), so I wonder if anyone could give me an idea of what kind of fuel consumption an R-44 pilot would really see. Specifics are not really important- a general number for flight planning purposes will do as long as it's in the ballpark. I'm putting a comparison chart together for a customer and I want to be as...(ahem) "fair and accurate" as possible.
Thanks.
Thanks.
Better red than ...
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16 USG per hour for the recip. engine O580. as trip fuel
Declines marginally with full carb heat on full all the time.
Watch out for :-
a. Ground burn time (taxi fuel usage) to account for part of the full fuel load
b. Asking for full tanks and the fueler not topping off to full both sides. Reduces fuel load by about 4USG and reduces available trip fuel plus contingency amount. Can be an issue if near range limitation.
Declines marginally with full carb heat on full all the time.
Watch out for :-
a. Ground burn time (taxi fuel usage) to account for part of the full fuel load
b. Asking for full tanks and the fueler not topping off to full both sides. Reduces fuel load by about 4USG and reduces available trip fuel plus contingency amount. Can be an issue if near range limitation.
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For Raven I
Depends (of course on) Temp/Hight and map setting.
'Forcing' (=max continuous) will increase consumption a lot and need at least 16 USG
Being more economic even by reducing to 100 knts IAS, and not being at MTOW would more go towards 15 USG
Mixing with work such as pipelines can push it down to 14.
So the general range I see is 14-16 USG.
I have seen on different threads that this would be marginally higher for the RII
delta3
'Forcing' (=max continuous) will increase consumption a lot and need at least 16 USG
Being more economic even by reducing to 100 knts IAS, and not being at MTOW would more go towards 15 USG
Mixing with work such as pipelines can push it down to 14.
So the general range I see is 14-16 USG.
I have seen on different threads that this would be marginally higher for the RII
delta3
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The best option is to full the tank incrementally and make yourself a dipstick. Each piston aircraft will burn at a different fuel rate for a lot of different reasons. Fill the tank, mark the broomstick at each different level and then go flying. Time VS fuel not in the tank = fuel burn.
Or you can guess at 16gallons or rely on the guage and try explaining that to the boss when you have the old orange light illuminate.
Or you can guess at 16gallons or rely on the guage and try explaining that to the boss when you have the old orange light illuminate.
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Fuel consumption
I have to plan long distance more than half of the flights, so its not the boss I worry about.
And I think its red not orange...
Delta3
And I think its red not orange...
Delta3
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i plan for 60 litres/hr = 15.8 of your gallons (i think!) in a hydraulic astro at sea level
i usually get 58 litres/hr in cruise (fuel flow meter, which seems pretty accurate based on how much it thinks i will have to put in to refuel)
this increases with hovering, carby heat, air conditioning, pax, altitude, etc
i usually get 58 litres/hr in cruise (fuel flow meter, which seems pretty accurate based on how much it thinks i will have to put in to refuel)
this increases with hovering, carby heat, air conditioning, pax, altitude, etc
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R44 I to R44 II
Billywizz
As the Raven I will in the next weeks be replaced by a R44 II, that concerns me a little. You suggest a 16 to 18 USG difference that is more than 10%.
Under same performance requirements, that is same TOW, same cruising speed, same temp etc, do you have an idea what differences to expect ?
d3
As the Raven I will in the next weeks be replaced by a R44 II, that concerns me a little. You suggest a 16 to 18 USG difference that is more than 10%.
Under same performance requirements, that is same TOW, same cruising speed, same temp etc, do you have an idea what differences to expect ?
d3