Seems this will help to increase sales of R44's, and give PPL(H) pilots a bad press!

DON'T DO IT! will be a bad end to your exciting day

Vfr

Why do people keep repeating the myth that a barrel roll is a 1 g manoeuvre? Think; how do you depart straight and level flight to commence the initial climb and, then, how do you pull out of the final dive?

I agree it is not (or does not need to be) a high g manouevre, but it does require more than one to be pulled.

Well, there is a margin, but not much. Not much at all...

Since it is a teetering rotorhead, it will need positive G during the whole manouvre, so one (not me!) could pull 0.5g over the top so not to loose too much height. The problem with this is that the responsiveness in the helicopter deteriorates, since it need the helicopters weight to pull on the rotordisc to respond. Less weight, less response - 0g no response, at least to my knowledge. There's been a 206 doing a barrel-roll due to stupid parachutists, having the same rotor construction principle and limitation.

The dynamics of aerobatic flight is very interesting and a good discussion would definately bring up a few learning-points on the design of a teetering rotorhead and other designs. And an understanding of why the POH says no to such things. Sometimes it's a design limitation other times a rule-limitation.

Saying that a barrel-roll is a 1g manouvre, shows a lack of understanding of the manouvre. First you have the pull-up, the more you pull it into the vertical, the more g you can pull over the top and keeping it positive. The interesting part is that if you pull it up too much, there's no energy or speed left for you to work with over the top. If you on the other hand don't pull it up far enough, you will probably see the ASI-needle pass the redline twice, and having to pull lots and lots of g's at the bottom.

From a teetering rotorhead point of view, I'd guess a split-S with a low speed entry would be better, but then, if you survive the first part, the obvious risk of overspeed is another thing to contemplate.

This is all in theory. Myself after competing on international level aerobatics in planks, I've never rolled a Cessna or Piper. I know they can do it, but they aren't built or certified to do it, so I don't. Horses for courses.

Bottom line is that if you have the experience and skill to perform it flawlessly, you also have the experience to never attempt it. If you don't have the experience to make it, it WILL be the last experience. And insurance premiums rises for everybody else.

Now get me that BO-105! :E


/2beers

stick a empty fuel drum on its side
hover taxi towards it
use the downwash to roll the barrel

then you can truthfully say you've done a barrel roll in a R44
Just don't try the aerobatic version!

:ok:

Really? silly me. I shall have to berate my old ab-initio FW instructor (A2 QFI) for incorrect gen. Even Neil Williams seems to have got it wrong too, then!

Neil Williams: Seldom wrong...
 

An easy way to look at the barrel roll:

If you take a flat gift-wrap string and make a loop with it (looks lika loop) and then pull the ends apart until the string is straight, there will be a 360deg twist on it (roll). Everything in between is a barrel roll.

Too easy! ;)

If you now take the ends and tie a knot instead, it's a snap-roll or lomcevak, depending on the knot-tieing skills. :ok:

As a final show: Take a pair of scissors and cut the string (and maybe your fingers) in multiple small pieces and suddenly you have a R44 doing a barrel-roll :E


/2beers

you can prove on paper that a 44 or even a 22 can do a loop or barrel roll but doing it is another story

Famous last words:
I wonder if ..... ?
Watch this!!!
I'll show you somthing.
Do you think that thing could do ......?

To find out, you could buy a shiny new R44 and install radio controll equipment and then we could all watch from the ground if that would work out. You could even program all the control inputs. PM me, when you are ready. I want to see the crash, too.

:E :E :E :E

In theory sounds fantastic,yet then I woke up :\ .
Leave the throwing around to the proper bits of kit .
areobatics for the plank pilots normal vfr civil choppers leave well alone.
sets a not particular good note for a ppl,new shiny chopper and the wrong attitude.........look what i can doooooooooooo?:{
Another point what operations manual civil choppers do allow you to do areobatics any takers,but I bet there are not many if any?

Why would you want to barrel roll a 44? Its easier to jump off a high building if you want to kill yourself! :ouch:

Maybe some kind person with a massive computer and CGI software might do this. Then we could all see it and stay alive. Gravity is okay it's the sudden stop.

thanks for the input, to cut a long story short, an aerodynamics arguement between colleagues led to debate on the theoretical possibility. Have since also heard rumors that it has been done in an r22? Am wishing i had of chosen another name than doucheman after having the dictionary meaning explained, but been a work nickname for too long. Thanks again

Don't know about an R44, but 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.

407 loop
 

and this was debated at great length in an earlier thread... see The Great Loop Debate

recommended reading for doucheman :ok:

Barrel loop
 

1. I have seen quite some years ago a 206 do it, so yes, it is possible. But NO you should not do this (I'll try to find out if the pilot is old and bold....)

2. Same old story as before about my R44 simulator : it really starts working well, but it takes quite some time to learn to fly with it . This looks more difficult than the real thing, you only have visual clues. I also approach it off-line, that is create sec by sec control sequences that I playback, but that takes time...

Up to now I stick with hover, landing, take-off, autorots etc and validiate standard enveloppes. Of course loops etc are tempting, and this is btw of course the first things my kids want to do with it, but so far margins seem incredibly thin and they seem to crash...


Computer used : standard (uptodate) PC.

Delta3

I remember reading somewhere on Rotorheads about an R22 rolling, airborne, not on the ground. (When? What thread? Dunno. Too many late nights ppruning, like right now...) If I remember correctly, it sounded like a low-G tail rotor-coupled roll. :ooh: Somehow the pilot survived, and Frank R. couldn't wait to talk to the lucky SOB. :cool:

The R in 44
 

It doesnt stand for RRRollling. That rotor head starts to do some funny things once the load ain't pointing down anymore.

Yes, this thread has been done before. But apart from the inadvisability of such shenanagins, why do people say such things cannot be done? Of course any helicopter can be looped and/or rolled, no matter how many (or few) blades it has. The various laws of nature are not suspended simply because we do not like the airframe or it's attached rotor system.

Well Rotordog....old trusty partner....shuck about 80 pounds and rent a 22 and put on a demo for us. Same construction as the 44 , more plentiful and a lot cheaper, thus easier to replace should theory and reality take divergent paths (along with some rather sensitive bits). We could watch a video tape of yer demo by remote computer....no need for solid overhead cover that way thus not as difficult logistically.

If you were to invite the IMAX crew done...we could slow the film speed way down....watch the blades as they twist, scoop, tuck, dive, warp, feather and all that....and see just how the dynamics work out. Think of the fame that would await you here.....with accolades from all around.

Since everybody knows that helicopters actually can't fly, the big thing is to get them off the ground. Once that has been dealt with, it shouldn't take more skill to actually roll it, should it? :cool:
For people lacking that skill, a good dynamic rollover with lots of bouncing around should count as a roll but then the guy or girl inside would need a low level endorsement/waiver first :E

That is an example of a very poorly executed roll.

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.

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 ...:ok:

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.

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

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 … :ok:

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).

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.]

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!

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

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.

For a RavenII about 16 gallons

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.

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

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.

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

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

R405
 

58 liters would also be my overall average

d3

A Raven II can burn about 18US gals per hr if you are flying around at max power for long periods.

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