Guimbal Cabri G2
The Cabri is a French helicopter. French helicopter rotors turn clockwise. And as such, that makes the Cabri the ideal an-initio platform for pilots progressing onto other helicopters in the Eurocopter/Airbus 'stable'.
I probably would have picked the G2 over the R22.
So I picked a school operating S300C (2.5 seater
) and did not regret it ever since. Not sure how well a G2 would have handled 460 lbs in the cockpit, the S300C did HOGE even when gassed up to 49gals.
Last edited by Reely340; 20th Oct 2015 at 12:13.
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lol that was almost true for me and my FI, he was a large bloke, when I first saw the R22 AND the FI for the first time I did wonder how it was going to get off the ground!! Spent so many hours rubbing shoulders that in the end I took the doors off, even in winter in the South Island of NZ!
hours rubbing shoulders that in the end I took the doors off, even in winter in the South Island of NZ!
the one in the flanell shirt with the door vents at max. is the student,
the one in the fleece jacket zippered shut reaching for cabin heat ist the FI.
Originally Posted by Reely340
If a) and b) would have been adressed wisely the G2 would be a perfect drop-in replacement for all the R22s, and I'd bet the accident rate would have been much lower.
Granted it does seem like this fenestron generates issues that others don't. Granted that the Cabri is no competition to the S300, it's just less capable regarding a couple of aspects. But it was obviously not designed as S300 competition either.
Please also note that every accident without injuries is not bad press for Bruno G., it's the best promo he can get!
Please also note that every accident without injuries is not bad press for Bruno G., it's the best promo he can get!
And you feel it was a sound design goal to come up with an "initial trainer for french machines" only?
Just imagine how a "G2.1" with S-300C type FI engine (icing, low G), left turning rotor (power pedal), more conventional feel of fenestron pedal action (no pilot induce LTE) together with Cabri's outstanding safety & conveniency features would sell....
I just find it sad, that french design pride resulted in so many of them rolling around on the ground due to pilot mishandling.
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Please also note that every accident without injuries is not bad press for Bruno G., it's the best promo he can get!
Originally Posted by Reely340
I just find it sad, that french design pride resulted in so many of them rolling around on the ground due to pilot mishandling.
Your point that the Cabri has "so many of them rolling around on the ground" (is it really sooo many?) has nothing to do with the fact that it has the clockwise MR. Otherwise pilots transitioning from one orientation to the other would routinely trash helicopters during training, which is not the case!
Going from one to the other is not that big of a deal and has been done by myriads of pilots for the last 65 years at least. So this is certainly not exclusively a training machine for clockwise rotary aviation. Pilots who learned on the Cabri will have no significant issues transitioning to a Bell, just like those who learned on an american helicopter had no significant issues transitioning into an EC! Don't try to create an issue that has never been one.
If it gets documented reliably that there is above-average numbers of training accidents in the Cabri, the cause(s) has to be properly evaluated.
I tell you now, if this becomes evident, the problem will not be the MR orientation. It could be the general fenestron handling characteristics combined with the allegedly Cabri-specific problem of certain regimes being difficult or not possible to recover from. This could certainly be fixed by training measures just like some of the Robinson issues were practically dealt with.
My ultimate small helicopter would be a JetA-powered Cabri with a Notar and offer at least the cabin space, rotor clearance and versatility of the S300.
Edit: Ok, that would be a 520N with Guimbal crashworthiness and remote central locking.
If it gets documented reliably that there is above-average numbers of training accidents in the Cabri
Bundesstelle für Flugunfalluntersuchung - Homepage and regard
the number of incidents and especially the years they ocurred
It could be the general fenestron handling characteristics
combined with the allegedly Cabri-specific problem of certain regimes being difficult or not possible to recover from
The aspect that I do find very scary is, that quite some of these yaw related accidents occurrend when a FI were aboard, training the student to control yaw! Safety leaflets won't address a problem adequately when even FIs deliberately demonstrating emergency procedures at their will (hence no surpirse failures as in real world) fail to conquer the beast.
The 60 years old fenestron newbie ******* up is okay to me, FIs on the other hand ought not struggle with the machine.
edit: one "nice" feature of the 300C is it hovers ugly with the rrpm below the green arc, let alone at 85%. It defnitely has a lot less thrust, hence you don't have any business there, pitch down throttle up is the only thing you can do (in that sequence, mind you!).
My ultimate small helicopter would be a JetA-powered Cabri with a Notar and offer at least the cabin space, rotor clearance and versatility of the S300.
Edit: Ok, that would be a 520N with Guimbal crashworthiness and remote central locking.
Check this out: K1 the ultra light helicopter | Konner Helicopters
Last edited by Reely340; 20th Oct 2015 at 16:22.
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Originally Posted by whoknows idont
Remember that this helicopter was originally designed in-house by EC and was supposed to be marketed and sold by EC.
The Cabri G2 has taken eight years to develop, according to Guimbal, who says: "Aerospatiale has come in as official sponsor when the helicopter has been 70% built.
"Aerospatiale is helping with rotor-blade moulding, flight testing support including telemetry equipment, safety assistance and test-pilot assistance, as well as ground tests," he says.
"Aerospatiale is helping with rotor-blade moulding, flight testing support including telemetry equipment, safety assistance and test-pilot assistance, as well as ground tests," he says.
I/C
Reely, I think you got the wrong idea from my posts. If you go back two pages in this thread you will find me asking angled questions about these issues.
If I may quote again;
I still have the same question regarding that: How much room would be necessary for this recovery? Instead of an answer all I got was a faint attempt of mocking my terminology.
What if the bottom of that mentioned descent profile is in a somewhat confined area? Is it really recoverable in practice under different conditions?
I also specifically picked the 269 to fly and to train, also I'm no Robinson fan and also I'm one of the very few people who don't see the Guimbal as the hottest thing since sliced bread. We are on the same page on all of those!
However I think that you missed the context and that you are totally off track with most of your conclusions. I clarified that in detail already.
As for the K1: I was speaking about production helicopters only. Not taking into account the numerous projects that are currently promising to soon be the holy grail of light or ultra light helicopters. Also for some reason UL helicopters still do not play a noticeable role in the training market. Who knows, maybe that will change at some point.
Duly noted. Thanks for clearing it up and thanks for the link, interesting material. It certainly invalidates some of the things I read on different web pages.
Edit: But the article does certainly read like this: Bruno G. was an engineer at AS to start with and started this as a private project, eventually at some point succeeded in pitching it. So no wonder it has the typical AS design elements. Also granted that it was in fact targeted to compete with the R22. How very ambitious it was to match the price tag...
If I may quote again;
Originally Posted by Freewheel
Not true. I was shown a 360 with power applied and pedals unchanged at the bottom of a standard descent profile. yaw ceased in less than another 30 degrees.
What if the bottom of that mentioned descent profile is in a somewhat confined area? Is it really recoverable in practice under different conditions?
I also specifically picked the 269 to fly and to train, also I'm no Robinson fan and also I'm one of the very few people who don't see the Guimbal as the hottest thing since sliced bread. We are on the same page on all of those!
However I think that you missed the context and that you are totally off track with most of your conclusions. I clarified that in detail already.
As for the K1: I was speaking about production helicopters only. Not taking into account the numerous projects that are currently promising to soon be the holy grail of light or ultra light helicopters. Also for some reason UL helicopters still do not play a noticeable role in the training market. Who knows, maybe that will change at some point.
Originally Posted by Ian Corrigible
Marketed yes, designed no. Per Flight:
Edit: But the article does certainly read like this: Bruno G. was an engineer at AS to start with and started this as a private project, eventually at some point succeeded in pitching it. So no wonder it has the typical AS design elements. Also granted that it was in fact targeted to compete with the R22. How very ambitious it was to match the price tag...
Last edited by whoknows idont; 20th Oct 2015 at 18:12.
I think you got the wrong idea from my posts.
Originally Posted by Freewheel
Not true. I was shown a 360 with power applied and pedals unchanged at the bottom of a standard descent profile. yaw ceased in less than another 30 degrees.
I still have the same question regarding that: How much room would be necessary for this recovery? Instead of an answer all I got was a faint attempt of mocking my terminology.
What if the bottom of that mentioned descent profile is in a somewhat confined area? Is it really recoverable in practice under different conditions?
Not true. I was shown a 360 with power applied and pedals unchanged at the bottom of a standard descent profile. yaw ceased in less than another 30 degrees.
I still have the same question regarding that: How much room would be necessary for this recovery? Instead of an answer all I got was a faint attempt of mocking my terminology.
What if the bottom of that mentioned descent profile is in a somewhat confined area? Is it really recoverable in practice under different conditions?
Maybe my training was sub par or I didn't pay attention but TRC failures with the TR still spinning (the only type of TR failure you can safely practize) can always be filed between "pedal stuck at power-on", "pedal stuck at power-off" or any point in between.
When stuck at power-on, e.g. 25° AoA at the S-300C TR, with decreasing airspeed the TR will eventually overpower the weather vane effect, thus I'd have to slip sideways to the right, and when crossing the runway at an angle I'd add fwd. cyclic and put down the pitch, to screach along the runway axis with hopefully no yaw.
When stuck at power-off, I'd again come in doing 50kts in 3feet AGL, and gradually back off fwd. cyclic to precisely before I'd loose the nose's attitude to the right, then I'd lower the pitch and move cylic in direction of the skids.
Maybe the coupling of pitch down with throttle off in the 300C makes torque control that easy, maybe this would lead to disaster in a G2 with governor..
Now, the "normal app. profile" I've been trained to follow is to avoid the H-V curve, meaning "at the bottom" I'd have to be at 3-6 feet doing 50 kts. So who want to do a 360 at that time? At that point I don't care what kind of failure the TR might have been suffering from, the weather vane keeps me straight and at 6ft I'll survive with aforementioned procedures. I have to demonstrate that at every annual review, and habitually do order an hour FI in mid year to keep emergency procedures fresh.
The TR failures the G2 crash guys seem to practize (TR failure in HIGE) appeare to me to be addressed in rather strange ways (messing with RRPM) instead of "landing immediately".
TR failure in HOGE I'd counter by immediately sticking the cyclic 45° into the direction the tail wants to swing (pick up speed) and increase or decrase (height permitting) pitch accordingly. When mandated by environment I'd pace to a nearby airfield to do the landing procedures mentioned above BUT being a PPL I shouldn't be in HOGE outside an airfield/LZ to begin with
But then again it could be them G2 students/FIs were training for other emergencies than those I've been introduced to, I'm just a newbie. If I'm missing something important please do not hesitate to explain it to me, besides the entertainment I'm lurking at pprune to learn from the pros.
Am I the only one who doesn't care or take any notice of direction of travel of MR ? I regularly jump into both types and most of the time would have to think which way they go . Depending on weights and wind, the amount , and sometimes even the pedal you need can change . Getting light on the skids is always a good thing as you can check T/R effect before lifting ...which can avoid embarrassment!!
Ps. I trained in and taught in the 300 and loved every minute
Ps. I trained in and taught in the 300 and loved every minute
Am I the only one who doesn't care or take any notice of direction of travel of MR ?
That would work nicely in S-300, MD500, EC120, EC135 etc..
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Am I the only one who doesn't care or take any notice of direction of travel of MR ? I regularly jump into both types and most of the time would have to think which way they go . Depending on weights and wind, the amount , and sometimes even the pedal you need can change . Getting light on the skids is always a good thing as you can check T/R effect before lifting ...which can avoid embarrassment!!
Ps. I trained in and taught in the 300 and loved every minute
Ps. I trained in and taught in the 300 and loved every minute
Nigel,
No you're not. Probably because you use an appropriate technique, as opposed to a reely bad one.
Who knows; power was sufficient to arrest ROD, input to stop yaw came only from pedal. The fenestron has huge authority within the appropriate RPM range, which is why it's limited the way it is.
Last edited by Freewheel; 21st Oct 2015 at 02:39. Reason: Addressing a sensible query to earlier remarks
Originally Posted by Reely340
Maybe my training was sub par or I didn't pay attention but TRC failures with the TR still spinning (the only type of TR failure you can safely practize) can always be filed between "pedal stuck at power-on", "pedal stuck at power-off" or any point in between.
Originally Posted by John R81
There are 2 things that may catch-out pilots on first moving to Fenestron tails. Nothing to be frightened of, just understand the physics of the machine you are flying and act appropriately.
One is that the thrust increase / peddle position is not linier, as shown in the Eurocopter service letter (link above), and the amount of pedal input needed is therefore much more than the un-initiated might expect.
The second is that the Fenestron tail is aerodynamically shaped - it is a wing - which provide anti-torque in forward flight. The total anti-torque provided to the pilot is therefore the sum of the tail and the fan. On approach, as speed bleeds, the thrust provided by the tail will reduce and without action by the pilot to replace this with additional fan input the heli will begin to crab through inadequate anti-torque (to the left for EC120, G2). If you let this start then peddle input to correct the crab occurs as speed continues to bleed on approach, further reducing the effect of the tail, and it is easy for the novice Fenestron driver to underestimate the amount of peddle needed to deal with BOTH of these events. As a result the crab worsens despite (inadequate) peddle input. Then something horrible and very sudden can happen: because the Fenestron is a "wing", the crab is changing the angle of attack. When this reaches 20 degrees the "wing" stalls and in an instant the driver loses all of the anti-torque provided by the wing, being left only with the effect from the fan. The machine was crabbing anyway (insufficient peddle input) and suddenly it will snap into a (fairly violent) torque spin.
Torque-spin like this can be controlled - bury your power foot (right for EC120, G2) to the peddle stop and keep it there. It will likely take a couple of revolutions to control the spin; but it will IF YOU KEEP YOUR FOOT TO THE STOP.
All helicopters have operating parameters, so fly within them. Do not let Fenestron machines yaw to torque as you bleed speed on approach, use the appropriate amount of power peddle early.
In several years operating EC120s I have not ever had a machine snap into torque spin on approach, though I did abandon 1 approach in my early days on type because in the particular conditions I was not quick enough to control the yaw on approach; rather than take a chance by continuing with a boot-full of right foot I simply added speed and went around. Not my finest moment - and didn't make that mistake on the subsequent approach.
Take a G2 flight with an instructor and he can demonstrate all this to you.
One is that the thrust increase / peddle position is not linier, as shown in the Eurocopter service letter (link above), and the amount of pedal input needed is therefore much more than the un-initiated might expect.
The second is that the Fenestron tail is aerodynamically shaped - it is a wing - which provide anti-torque in forward flight. The total anti-torque provided to the pilot is therefore the sum of the tail and the fan. On approach, as speed bleeds, the thrust provided by the tail will reduce and without action by the pilot to replace this with additional fan input the heli will begin to crab through inadequate anti-torque (to the left for EC120, G2). If you let this start then peddle input to correct the crab occurs as speed continues to bleed on approach, further reducing the effect of the tail, and it is easy for the novice Fenestron driver to underestimate the amount of peddle needed to deal with BOTH of these events. As a result the crab worsens despite (inadequate) peddle input. Then something horrible and very sudden can happen: because the Fenestron is a "wing", the crab is changing the angle of attack. When this reaches 20 degrees the "wing" stalls and in an instant the driver loses all of the anti-torque provided by the wing, being left only with the effect from the fan. The machine was crabbing anyway (insufficient peddle input) and suddenly it will snap into a (fairly violent) torque spin.
Torque-spin like this can be controlled - bury your power foot (right for EC120, G2) to the peddle stop and keep it there. It will likely take a couple of revolutions to control the spin; but it will IF YOU KEEP YOUR FOOT TO THE STOP.
All helicopters have operating parameters, so fly within them. Do not let Fenestron machines yaw to torque as you bleed speed on approach, use the appropriate amount of power peddle early.
In several years operating EC120s I have not ever had a machine snap into torque spin on approach, though I did abandon 1 approach in my early days on type because in the particular conditions I was not quick enough to control the yaw on approach; rather than take a chance by continuing with a boot-full of right foot I simply added speed and went around. Not my finest moment - and didn't make that mistake on the subsequent approach.
Take a G2 flight with an instructor and he can demonstrate all this to you.
We are not talking about a TR failure here, forget what you learned because this doesn't apply here. Read again post #826:
I'm talking about VH-ZZT and VH-CDU Search
- both accidents occurred from stationary HIGE
- were training exercises
- were meant to demonstrae yaw control in case of TR failure
- were caused by - to me - weird messing with RRPM
- ignored the "land immediately" mandated by AFM
- hovering while "student listened to FI for task"
- during training exercise
- uncommanded right(!) turn developed
- FI was unable to stop spin
Maybe there were other approach related Cabri accidents but I find those three appalling enough.
Am I the only one who doesn't care or take any notice of direction of travel of MR ? I regularly jump into both types and most of the time would have to think which way they go
I'd expect that someone with say +1000h in a left turning Bell could not have prevented his brain to internalize certain pedal action when adding pitch.
I'd have guessed that at that experience level one would not pull pitch and wait to see and learn from looking out of the cockpit what kind of ac he is sitting in today.
Last time I was hovering I was truly astonished that my feet "did the right thing" by themselves, w/o waiting for the onset of yaw and reacting afterwards,
as I definitely did during early training. I'm not sure what would happen if I'd jump into an EC120 the next day.
How do you do that? Does your brain switch from EC mode to Bell mode by deducting rotor direction from peripheral cockpit panel appearance?
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Transitioning from different types (left vs right turning MR) in normal operations is not usually a big issue. What can be an issue is when you need to react to something very quickly, so if you have a lot more time in one particular type over the other, you may instinctively use incorrect control inputs.
But this is starting to drift the OP
But this is starting to drift the OP
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People have previously asked how the R22 accident statistics in its early years compare to the G2. I'm more curious how they compare since the G2 came into being. I suspect the R22 accident rate in recent times is considerably lower, although sadly there have been fatalities. However, I do not think you can conclude that this is due to the design capabilities of the machines themselves, but more the fact that the R22 has a vastly higher number of flying hours under its belt, and a lot more investigation has taken place into its weaknesses of operation. These weaknesses have been well incorporated into pilot training. I suspect we still have a lot more to learn about the G2 and what is causing these accidents. Clearly there are a lot of pilots who are not flying the things as they need to be flown.
It is almost as if people are keen to throw the things around an awful lot more than they would an R22, simply because they can - but then they are finding actually, maybe they cannot because they're not quite experienced enough yet? Complacency of a sort maybe? ie people are doing things beyond their experience levels, or perhaps aren't concentrating as much as they would in an R22, and the G2 is biting them?
My gut feeling is that once people start to respect these machines, and recognise that they are not quite so simple to fly - demanding as much respect and concentration as an R22, the accident rate will plummet.
It is almost as if people are keen to throw the things around an awful lot more than they would an R22, simply because they can - but then they are finding actually, maybe they cannot because they're not quite experienced enough yet? Complacency of a sort maybe? ie people are doing things beyond their experience levels, or perhaps aren't concentrating as much as they would in an R22, and the G2 is biting them?
My gut feeling is that once people start to respect these machines, and recognise that they are not quite so simple to fly - demanding as much respect and concentration as an R22, the accident rate will plummet.
