Guimbal Cabri G2

[Hughes500]

You can make figures say whatever you want, just ask my accountant ! However if one looks at the table it is rather alarming. What would be interesting to know on the Cabri incidents, had the pilots flown nothing else or were pilots doing type ratings ?As I said in a previous post the early student ppl is very reactive and doesn't anticipate enough ( how can you until you have some experience ) In theory the pilot starting on a Cabri should be ok, but is this the case ?

[Prizmatic]

Originally Posted by ApolloHeli

Out of curiosity, why do you think they have bad representation in the UK?

I was talking about the UK dealership. The guys that originally brought the Cabri to the UK were responsible for its huge success there but they are sadly no longer involved.

As for Malones hatchet job in Pilot I think enough has been said.

[John Eacott]

Originally Posted by AMDEC

The reproach that can be made about the article in "Pilot" is not what is said of the Cabri, but that it is presented as a problem of the Cabri only. A small look in accident reports databases.(and you could expect that from a journalist) shows that it is a global problem on small heicopters.

Helicopters involved in loss of yaw control accidents found in accident reports databases (2010-2016)

This data presentation has almost a negative value as it has no reference to hours flown nor fleet numbers. As a simple raw number there is absolutely no useable correlation between aircraft types other than shock value to infer unproven handling issues.

[AMDEC]

Losses of yaw control on helicopters

I fully agree that the number of accidents should be related to the number of flight hours. I was not able to find the information.

I do not say that the helicopters that have the largest number of accidents are worse and in fact they are probably only the most numerous. It is however not fair to point out a specific one. The conclusion I would draw from that figure is that the huge number of losses of yaw control has surely little to do with the helicopter design.

[aa777888]

Some more data to think about, trying to compare apples to apples (is it said the same way in the King's English?):

- As of the end of May there are 869 R22's of all types and 31 G2's in the FAA registration database for a total of 900 ships, so the G2 is 3.4% of those.
- Since Nov 2016 in the NTSB database when G2's started to appear there are 47 R22 incidents and 5 G2 incidents for a total of 52, of which the G2 accounted for 9.6%.
- On a per ship basis they are crashing nearly 3 times as many as R22's.
- Note that I did not say at "3 times the rate" as I don't have any fleet hour data (does anyone?)

Nevertheless, some interesting numbers to contemplate.

Guimbal needs to build a G2 Mark II with a slightly bigger engine and a regular tail rotor. Now that would be sweet (and cost the same as an R44).

[evil7]

I doubt they need to change to conventional TR as mostly the reason for the control loss sits between the earcovers of the headset

[Robbiee]

I don't think that article was all that bad. It simply points out that if you're going to fly a Cabri (especially if you're used to the Robby tail rotor) you need to pay more attention to the pedals. Just like in the old days, if you were going to fly a Robby after being used to a Schweizer, you need to pay more attention to well,...lots of things.

Anyway, seems like putting a real tail rotor in that thing would defeat the advertised purpose of the Cabri, which I believe was to make it easier for pilots to transition into other backwards spinning, fenestron equipped, Eurocopters?

,...and forgive my Yankee ignorance, but isn't it "The Queen's English"?

[aa777888]

Originally Posted by evil7

I doubt they need to change to conventional TR as mostly the reason for the control loss sits between the earcovers of the headset

You could just as easily re-write that to say:

"On helicopter XXXX I doubt they need to change YYYYY as mostly the reason for the control loss sits between the earcovers of the headset." That's true, but my point is that some things are easier or harder than others on any given helicopter. The best helicopter would make everything very easy. But design trade-offs always seem to preclude doing that. All I know is that I became comfortable with an R22 tail rotor much more quickly than the fenestron. Others seem to fighting the same battle, and sometimes losing.

King's or Queen's English? I don't know!

[Prizmatic]

Originally Posted by aa777888

You could just as easily re-write that to say:

"On helicopter XXXX I doubt they need to change YYYYY as mostly the reason for the control loss sits between the earcovers of the headset." That's true, but my point is that some things are easier or harder than others on any given helicopter. The best helicopter would make everything very easy. But design trade-offs always seem to preclude doing that. All I know is that I became comfortable with an R22 tail rotor much more quickly than the fenestron. Others seem to fighting the same battle, and sometimes losing.

King's or Queen's English? I don't know!

I don’t understand, perhaps you could clarify? You became comfortable with the R22 TR more quickly than the fenestron? Did you convert from TR Tm fenestron? I learnt to fly. Cabri and have no experience with TRs and it obviously feels totally natural and comfortable to me. This continuing debate seems non sensical to me. If you get out of an automatic car into a manual and expect to pull away without using the clutch you’re not going to get very far. It’s all about difference training but if you do make a mistake at least you will walk away from a Cabri.

[aa777888]

Originally Posted by Prizmatic

I don’t understand, perhaps you could clarify? You became comfortable with the R22 TR more quickly than the fenestron?

Yes, exactly that.

Did you convert from TR Tm fenestron?

Yes, but I would hardly call the conversion complete. I've only got 3 hours on fenestron equipped helicopters.

I learnt to fly. Cabri and have no experience with TRs and it obviously feels totally natural and comfortable to me.

Of course it does. You have no basis for comparison.

This continuing debate seems non sensical to me. If you get out of an automatic car into a manual and expect to pull away without using the clutch you’re not going to get very far. It’s all about difference training but if you do make a mistake at least you will walk away from a Cabri.

No, it isn't nonsensical. Some things are harder to do than others on different helicopters. For instance, continuing the G2 vs R22 theme, and something I mentioned previously: do an auto in a G2, then do one in an R22. Then tell me which one is easier. I might whine a little (I'd hardly call it complaining ) about the fenestron in the G2, but I'd rather do auto's all day long in a G2 than a 22. Or a 44 or 66 for that matter!

[Robbiee]

Originally Posted by aa777888

Yes, exactly that.
Yes, but I would hardly call the conversion complete. I've only got 3 hours on fenestron equipped helicopters.
Of course it does. You have no basis for comparison.
No, it isn't nonsensical. Some things are harder to do than others on different helicopters. For instance, continuing the G2 vs R22 theme, and something I mentioned previously: do an auto in a G2, then do one in an R22. Then tell me which one is easier. I might whine a little (I'd hardly call it complaining ) about the fenestron in the G2, but I'd rather do auto's all day long in a G2 than a 22. Or a 44 or 66 for that matter!

I'll go you guys one further. When I was learning how to drive a stick, I first tried in my parents new '86 Acura and was jackrabbitting all over the place. My father then put me in this old '65 Mercades he had and I found it a hell of a lot easier to learn on! Simply put, the newer clutch had no 'feel" to it, but the heavier, older, pressure plate style cluch of the Merc made it easier for me to feel where the engagement point was.

So yeah, different designs do make a difference in the learning process.

[rotorfossil]

The difference between the R22 and the Cabris’yaw control on the approach to the hover is simply the greater need for anticipation of the large and under some circumstances more sudden pedal movement on the Cabri. The gain in safety of the fenestron (you can’t walk into it) and the fact that it looks nicer is offset by the fact that it is less efficient ( about 17% I have heard) due to its smaller diameter. To offset this the fin is angled to unload the fenestron in the cruise. As you slow down on the approach, this effect is lost and hence has to be replaced by quite a large pedal movement. If there is a crosswind from the right, the fin stalls quite suddenly, exaggerating the need for a large pedal movement.
Simply put, the required pedal movement in the R22 is smaller and relatively linear. On the Cabri, it is larger and not linear, but like most things you get used to it.

[homonculus]

but like most things you get used to it.

The problem is that the accident history implies some pilots at least have not got used to it, or not got used to it in time. We can argue about whether it is justified design or whether training is inadequate but until something is done it appears a lot of expensive metal will be bent and there will be a risk of injury.

[Robbiee]

Originally Posted by rotorfossil

The gain in safety of the fenestron (you can’t walk into it)...

That safety gain is only for people who feel the need to walk around a running helicopter, not pilots, so is it really worth it?

,...its not like the Cabri is widely used in tours.

[Mutley1013]

I guess one of the problems with communicating by text is that sometimes it is hard to spot a joke, especially a sarcastic one. It took me a couple of reads, but I did finally understand your witticism Robbiee.

[A681001]

there is a graph on this Cabri accident report showing thrust curves comparison between fenestron and conventional tail rotors, maybe its been on this thread before ? , anyway interesting read
https://www.caa.govt.nz/assets/legac...rts/ZK-IMZ.pdf

[Hot and Hi]

Originally Posted by Robbiee

That safety gain is only for people who feel the need to walk around a running helicopter, not pilots, so is it really worth it?

,...its not like the Cabri is widely used in tours.

I know this was slightly tongue-in-cheek. However, the training paradigm here is that people should learn in a ‘cheap’ airbus helicopters to then later fly in expensive Airbus helicopters. So that from the onset students are used to the CW rotating main rotor and the Fenestron.

Maybe that paradigm is entirely false.

Could it be that you need to train in a most simple, straight forward helicopter with efficient, direct controls.

From experience we would say that the proficiency gained from a few hundred hours, even if it was on American-style helicopters only, allows us to adjust with relative ease and safely to an entirely different type (incl fenestron, or MR direction).

It is not only for cost reasons alone that people learn to fly (fix wing) in a C150, and learn to drive in a Polo.

[ApolloHeli]

Originally Posted by A681001

there is a graph on this Cabri accident report showing thrust curves comparison between fenestron and conventional tail rotors, maybe its been on this thread before ? , anyway interesting read
https://www.caa.govt.nz/assets/legac...rts/ZK-IMZ.pdf

I'm not sure if those have been posted on here either, but any Cabri pilot should have seen those. Its a small excerpt from a 10-page Safety Letter (SL 12-001 A) that Guimbal released and has been offering training for inexperienced pilots / instructors for. That's why I call BS on PM's article to claim Guimbal has been sitting idle for all these incidents - they've been producing safety letters and offering further training to instructors etc. It's just a failure on each individual operator's part to pass down some of this info to the pilots actually flying them.

P.S. I've got the fully Safety Letter (SL 12-001 A) which I can PDF scan and share if anyone is interested.

[Hot and Hi]

SL 12-001 A

You can find the Service Letter here.

[Robbiee]

Originally Posted by Hot and Hi

You can find the Service Letter here.

"Our design is awesome, if anything goes wrong its the pilot's fault". Typical Robinson Safety Notice.

,...oh wait