French Helicopters

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Undried Plum
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Re: French Helicopters

#21 Post by Undried Plum » Mon Jun 29, 2020 7:29 am

Ja.

Ganger Rolf was from my spiritual hometown of Ålesund. Giske, actually.

He was so fukkin tall that when he rode a horse he had to run to keep up with the nag. "ganger, in noggiespeak, means to run.

The ffrench are a whole different bunch. They are just weeds.

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Re: French Helicopters

#22 Post by TheGreenGoblin » Mon Jun 29, 2020 7:46 am

Some more childhood remeniscences reference the Super Frelon.

I was taken to see a military display with my friend Paul, by his father, a taciturn Englishman, who was a senior electrical engineer with ESKOM (the reason that utility actually used to operate efficiently) and there parked on the parade ground was one of those beauties, sitting silently in the centre of the field and when two bone domed pilots marched out, climbed in and what appeared to be a heat haze started to dance around the aircraft (I was unaware of helicopter turbines at that stage) and the machine's blades started to turn and I was lost in admiration for those two sky God's and their wonderful machine. The ensuing paradrop from the helicopter was as nothing to seeing it fly!

They were used in big way later in South Africa's first big foray into Angola!

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Re: French Helicopters

#23 Post by Seenenough » Tue Jun 30, 2020 1:50 am

TheGreenGoblin wrote:
Sun Jun 28, 2020 11:51 am
FD2 wrote:
Sun Jun 28, 2020 3:04 am
I had a few hours flying the Alouette SA316 (Mk 3) in Port Harcourt and a 'jolly' in a Mk 2 from St Mandrier with the French Navy.

I was amazed at how much trust the pilots had in the machines and it was explained to me that because the engines ran at constant rpm (33,000 I think it was), they suffered remarkably little wear and tear unlike the more 'conventional' helicopter engines which were constantly accelerating and decelerating and failing more frequently.

To prove it the French NCO pilot flew me up a 500ft cliff with the aircraft facing and the main rotor blades a few feet from the rockface and nowhere to go if the engine stopped. "C'est normal", he told me, before flying down to beat up the nearby nudist beach.
A badly grabbed photo by Herman Potgieter... of 3 Alouettes taken from a hole in the Drakensberg mountains (Gatberg). It seems that the Alouette III inspired confidence globally in those who flew them.


Gatberg.JPG
I enjoyed the experience of putting a skid down on top of Gatberg and The Bell and then a bit later making a landing inside Monks Cowl to get a bit of water from the falls to mix with a bit of Jack as was the custom.I was able to do this with a B2 Squirrel which was well up to the task.

It is then customary to write ones name on the roll of paper inside the Cookie Jar up on the top of The Dragon's Back.I am forever grateful for the experience.

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Re: French Helicopters

#24 Post by TheGreenGoblin » Tue Jun 30, 2020 4:42 am

Aerospatiale SA342 Gazelle

Since its service introduction in 1973, the Sud Aviation (later Aerospatiale) Gazelle series of lightweight helicopters proved popular with many foreign operators. The type was taken into service in both civilian and military circles and is regarded as a robust and versatile package despite its lightweight classification. The primary operator of the series remains the French Army, for whom it was developed for, and the line has seen considerable combat service for its time in the sky.

Development of the Gazelle stemmed from a French Army requirement calling for a successor to follow the aging fleet of Aerospatiale "Alouette III" light helicopters. This led the French concern of Sud Aviation to begin development of such a new rotary-wing platform in 1966 resulting in the "SA340" prototype which carried a conventional tail unit from the Alouette II helicopter series. A successful first-flight was undertaken on April 7th, 1967 and four pre-series aircraft (SA341) were ultimately completed. Before the end, the conventional tail rotor unit gave way to a Fenestron tail rotor unit. Evaluations of this helicopter system revealed a platform that was highly agile and fast, allowing the design to claim several speed records of the time. This preceded service entry of what became the "Gazelle" in 1973 and the helicopter has since been built under various brand labels: Sud Aviation (later to become Aerospatiale), Westland and Soko.

It was designed by Sud Aviation, later Aérospatiale, and manufactured in France and the United Kingdom through a joint production agreement with Westland Aircraft.

Early on, the Gazelle attracted British interest, which resulted in a major joint development and production work share agreement between Sud Aviation and Westland. The deal, signed in February 1967, allowed the production in Britain of 292 Gazelles and 48 Sud Aviation SA 330 Puma medium transport helicopters ordered by the British armed forces; in return Sud Aviation was given a work share in the manufacturing programme for the 40 Westland Lynx naval helicopters for the French Navy. Additionally, Westland would have a 65% work share in the manufacturing, and be a joint partner to Sud Aviation on further refinements and upgrades to the Gazelle. Westland would produce a total of 262 Gazelles of various models, mainly for various branches of the British armed forces, Gazelles for the civil market were also produced.

The first prototype SA 340 flew for the first time on 7 April 1967, it initially flew with a conventional tail rotor taken from the Alouette II. The tail was replaced in early 1968 with the distinctive fenestron tail on the second prototype Four SA 341 prototypes were flown, including one for British firm Westland Helicopters. On 6 August 1971, the first production Gazelle conducted its first flight. On 13 May 1967, a Gazelle demonstrated its speed capabilities when two separate world speed records were broken on a closed course, achieving speeds of 307 km/h over 3 kilometres and 292 km/h over 100 kilometres.

The Royal Navy's Gazelles entered service in December 1974 with 705 Naval Air Squadron, Culdrose, to provide all-through flying training in preparation for the Westland Lynx's service entry. A total of 23 Gazelles were ordered for Culdrose.[63] Army-owned AH.1s also entered service with 3 Commando Brigade Air Squadron (3 CBAS) of the Royal Marines and later, the Commando Helicopter Force (CHF) of the Fleet Air Arm, where they operated as utility and reconnaissance helicopters in support of the Royal Marines.[64] The 12 Gazelles for 3 CBAS had entered service in 1975,[65] by which time, there were 310 Gazelles on order for the British military
- from WIkipedia - https://en.wikipedia.org/wiki/A%C3%A9rospatiale_Gazelle
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Re: French Helicopters

#25 Post by G-CPTN » Tue Jun 30, 2020 5:06 am

Thanks - interesting - it lead me on to read about Lynx, Wildcat and then AW139s.

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Re: French Helicopters

#26 Post by FD2 » Tue Jun 30, 2020 5:07 am

Many years ago a French pilot told me that the big drawback with the Super Frelon was that it was not very manoeuvrable and that there were quite severe restrictions on control inputs. I have no idea if that's true or just a bit of tosh, or if so it was something corrected on later versions. Did you hear anything to that effect in South Africa?

A friend gave me a ride in a Gazelle at Culdrose after they had replaced the Hillers. I found it a bit restrictive as the cockpit was small but the manoeuvrability was superb and with a high inertia head you could touch down from an engine off landing, then take off again and move to a more suitable area a few yards away before the Nr got too low!

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Re: French Helicopters

#27 Post by CharlieOneSix » Tue Jun 30, 2020 8:36 am

In '74 the head honcho's Bo105 was due to be offline for some time so I was given a Gazelle conversion. I think the Air Registration Board was still around in those days and I passed their technical exam before doing the flying bit. After 2.5 hours of conversion flying I was made redundant so never got the 3 hours necessary to get it on my licence!

Like several French helicopters with weak hydraulic systems - FD2, maybe including the Super Frelon? - you could quite easily lock the controls if they were mishandled and a demonstration at a safe altitude was part of the conversion course. Control lock occurs when the aerodynamic forces on the blades overcome the power of the hydraulics - usually referred to as jack stall. There have been quite a few accidents where a Gazelle - or a AS350/355 - was put in a fast descending turn to the right, followed by a pull back on the cyclic. The controls locked up with the inevitable result if the machine was at low level. It was not unknown for the accident to follow the words "Watch this!".
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Re: French Helicopters

#28 Post by TheGreenGoblin » Tue Jun 30, 2020 10:27 am

I suspect that C16 has the answer there, but I have pinged FD2's question to an old school friend, an ex 30 Squadron SAAF pilot, who flew the 3 engine beast before it was phased out in 1989.

The development of the SE 3200 Frelon, what was to become the the successful Frelon (or Hornet), was an initially pretty disastrous affair...
The SE 3200 Frelon was a large helicopter, someone said not very aesthetically attractive, of conventional layout, powered by three Turbomeca Turmo III free-turbine engines all geared to a single transmission. This innovative solution, quite unusual, allowed the helicopter to complete the mission in case of an engine failure.
Two large streamlined fuel tanks designed to serve as floats in the event of a ditching were mounted to the fuselage sides. The helicopter had a tricycle fixed landing gear.

In order to reduce its size the main rotor blades could be folded rearward and the tailboom sideways. This allowed the direct loading of vehicles into the wide cargo cabin where there was space for 24 fully equipped soldiers, or 15 wounded on a stretcher and two attendants or a 1,995 kg (4,400 lb.) load.

Flight tests, marked by some incidents, happily ended with only material damages, revealed several technical problems for example with the tail rotor, the self-adjusting horizontal stabilizer and the rotor blades balance.

The poor performances were attributable to the fact that the empty weight was about one ton (2,205 lb. higher than expected (4,500 kg/9,920 lb.). Several changes were made in order to improve flight performance: the tailboom, for example, was redesigned and stretched by 80 cm and equipped with a larger five blade tail rotor.

The SE 3200 Frelon was evaluated by the Center Essai de Vol (CEV now known as DGA – acronym of Direction Générale de l'Armement - Essais en vol, the French organisation charged to test aircraft, aeronautical armaments and equipment before being used for military or civilian tasks. In its evaluation report, the CEV wrote that globally the contract clauses were fullfilled but the flight characteristics were mediocre, in particular as regards the control around the pitch axis, that the empty weight was too high in relation to the take-off weight and the centre of gravity margins were too limited which reduced the usage of the helicopter.

Other shortcomings concerned the high level of vibrations which led to the apparition of cracks and straps, the limited accessibility to the turbines and transmission area, and minor but continuous technical failures.

At the beginning of 1963 with the appearance of the new SA 321 Super Frelon, and after about 200 hours of test flights logged on both prototypes, the development program was cancelled and the plans to produce the SA 3200 in series definitively abandoned.

All things considered it can be said that the SA 3200 was a fiasco, one of the few if we consider the prolific French helicopter production. At that time Sud Aviation was manufacturing the excellent Alouette 2 and 3 series and developing the SA 330 Puma that achieved a remarkable commercial success.
Ultimately, after major improvements were made, the SA 321 Super Frelon was a big success and still flies as the Chinese Avicopter AC313 which morphed into the military Changi Z18 over 50 years after its maiden flight... read the interesting devlopment story here..

Super Frelon story...

Speaking to C16's interesting point it is worth having a look at complexity of the 4 bladed Super Frelon's rotor head, note the redundancy built into the hydraulics system.

SA321G Super Frelon Rotor Head.JPG
SA321G Super Frelon Rotor Head.JPG (52.97 KiB) Viewed 624 times
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Re: French Helicopters

#29 Post by FD2 » Tue Jun 30, 2020 11:02 am

in particular as regards the control around the pitch axis Yes - that was what the man said. Trying to flare the aircraft hard and levelling quickly to establish a hover was not 'advisable' - the clip makes it look like a limited power approach.

Thanks C16 - that also rings a bell from when I spent some time doing charter work on the 350 and 355. OK light but take care when heavy.

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Re: French Helicopters

#30 Post by fareastdriver » Tue Jun 30, 2020 12:01 pm

it is worth having a look at complexity of the 4 bladed Super Frelon's rotor head

All the Frelon and Z6s I have seen have had six bladed rotors.

It should be noticed that the Super Frelon's rotor rotates anticlockwise looking from the top. This is at variance with all previous French designs because the transmission was designed with a lot of input from Sikorsky helicopters.

I saw the first Super Frelons destined for China at Marignane in 1978. They were complete but waiting for clearance, because of the American input, from the White House before they could be exported.

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Re: French Helicopters

#31 Post by CharlieOneSix » Tue Jun 30, 2020 12:03 pm

Have a look at 5.12 in this video - I couldn't find a video of this AS355(?) incident on its own. I don't know the cause of the accident but I suggest it was down to jack stall. A fast pull up followed by excessive roll, then when he tried to straighten out the roll and pull collective and cyclic everything froze on him. Far too low to relax on the controls and fly out of it. Another case of "Watch this!"
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Re: French Helicopters

#32 Post by TheGreenGoblin » Tue Jun 30, 2020 12:05 pm

fareastdriver wrote:
Tue Jun 30, 2020 12:01 pm
it is worth having a look at complexity of the 4 bladed Super Frelon's rotor head

All the Frelon and Z6s I have seen have had six bladed rotors.

It should be noticed that the Super Frelon's rotor rotates anticlockwise looking from the top. This is at variance with all previous French designs because the transmission was designed with a lot of input from Sikorsky helicopters.

I saw the first Super Frelons destined for China at Marignane in 1978. They were complete but waiting for clearance, because of the American input, from the White House before they could be exported.
You are quite correct. My error.
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Re: French Helicopters

#33 Post by Seenenough » Tue Jun 30, 2020 3:54 pm

CharlieOneSix wrote:
Tue Jun 30, 2020 12:03 pm
Have a look at 5.12 in this video - I couldn't find a video of this AS355(?) incident on its own. I don't know the cause of the accident but I suggest it was down to jack stall. A fast pull up followed by excessive roll, then when he tried to straighten out the roll and pull collective and cyclic everything froze on him. Far too low to relax on the controls and fly out of it. Another case of "Watch this!"
.
Also there nowhere near enough forward speed that had been generated before making his "watch this"turn for the crowd.

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Re: French Helicopters

#34 Post by TheGreenGoblin » Tue Jun 30, 2020 6:13 pm

CharlieOneSix wrote:
Tue Jun 30, 2020 12:03 pm
Have a look at 5.12 in this video - I couldn't find a video of this AS355(?) incident on its own. I don't know the cause of the accident but I suggest it was down to jack stall. !"
Here is the stand alone video C16.



I had never heard of this phenomenon until C16 raised it here.
Pilots who learn to fly in smaller helicopters probably hear very little about servo transparency, yet this phenomenon has caused or played a role in several accidents. When giving flight reviews I have found some helicopter pilots who totally misunderstand why and how it happens. However, the concept is not too difficult to understand.

Because of the higher control forces in larger helicopters, hydraulically boosted servo actuators are used to assist the flight controls. The maximum force that these servo actuators can produce is constant and is a function of hydraulic pressure and servo characteristics. Engineers design the hydraulic system to adequately handle all aerodynamic forces required during approved maneuvers. Even so, with certain aggressive maneuvering it is possible for the aerodynamic forces in the rotor system to exceed the maximum force produced by the servo actuators. At this point, the force required to move the flight controls becomes relatively high and could give an unaware pilot the impression that the controls are jammed. To prevent servo transparency, pilots should avoid abrupt and aggressive maneuvering with combinations of high airspeed, high collective pitch, high gross weight, and high-density altitude.

The good news is that this phenomenon occurs smoothly, and can be managed properly if the pilot anticipates it during an abrupt or high-G load maneuver. On clockwise-turning main rotor systems the right servo receives the highest load, so servo transparency produces an un-commanded right and aft cyclic movement accompanied by down collective. The pilot should follow (not fight) the control movement and allow the collective pitch to decrease while monitoring rotor rpm, especially at very low collective pitch settings. The objective is to reduce the overall load on the main rotor system. It normally takes about two seconds for the load to ease and hydraulic assistance to be restored. However, be aware that if the pilot is fighting the controls when this happens, the force being applied to the controls could result in an abrupt undesired opposite control movement.

Many of these accidents have happened while aggressively flying the helicopter at low altitudes, leaving very little time to recover. Most important for avoiding this kind of accident is to follow the aircraft limitations published in the helicopter’s flight manual.
https://blog.aopa.org/aopa/2010/01/08/s ... nsparency/
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Re: French Helicopters

#35 Post by TheGreenGoblin » Tue Jun 30, 2020 8:49 pm

TheGreenGoblin wrote:
Tue Jun 30, 2020 6:13 pm
CharlieOneSix wrote:
Tue Jun 30, 2020 12:03 pm
Have a look at 5.12 in this video - I couldn't find a video of this AS355(?) incident on its own. I don't know the cause of the accident but I suggest it was down to jack stall. !"
https://blog.aopa.org/aopa/2010/01/08/s ... nsparency/
Final report on a similar crash in NZ!

https://taic.org.nz/sites/default/files ... 94-022.pdf
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Re: French Helicopters

#36 Post by FD2 » Tue Jun 30, 2020 11:26 pm

Also there nowhere near enough forward speed that had been generated before making his "watch this"turn for the crowd. If he was faster he probably would have pulled even more power in the turn.

Don't know what type(s) you fly Seen but it's not really even a 'watch me' wingover, more a steep turn and he had more than enough airspeed to do it safely, unless he was too rough on the controls. Perhaps he pulled too much collective in the turn and/or the aircraft was very heavy to cause the jack stall.

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Re: French Helicopters

#37 Post by FD2 » Tue Jun 30, 2020 11:42 pm

Thanks for pointing out the NZ crash GG. More wazzing around above the pilot's ability level? - I'll have a look!

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Re: French Helicopters

#38 Post by Seenenough » Wed Jul 01, 2020 2:20 am

FD2 wrote:
Tue Jun 30, 2020 11:26 pm
Also there nowhere near enough forward speed that had been generated before making his "watch this"turn for the crowd. If he was faster he probably would have pulled even more power in the turn.

Don't know what type(s) you fly Seen but it's not really even a 'watch me' wingover, more a steep turn and he had more than enough airspeed to do it safely, unless he was too rough on the controls. Perhaps he pulled too much collective in the turn and/or the aircraft was very heavy to cause the jack stall.
I was rated for AS350/355.

If you look closely the pilot hesitated a little before he went into what looks like too steep a turn for the speed and he appears to slide sideways at which time I suspect he grabbed a handful of collective which put the already heavily loaded hydros into a system stall.Had he had some speed to make a more ball in the middle turn without letting his nose drop he likely would not have needed to yank hard on the collective and maybe have got away with it.

I was always taught you should not make big cyclic inputs and collective inputs together.

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Re: French Helicopters

#39 Post by FD2 » Wed Jul 01, 2020 4:03 am

I was always taught you should not make big cyclic inputs and collective inputs together. That's very much a 350 and 355 thing, as machines with good hydraulic systems should be able to take both at the same time. Be that as it may, in this case I can't see any evidence of a problem until what appears to be a levelling caused by a jack stall during a steep left turn, almost righting the aircraft and then a descent into the sea. I guess if he had the nerve to do it, he should have unloaded the controls and may have been able to pull out when the jacks unlocked, but every fibre in his body was telling him to pull up the collective and back on the cyclic, which would just have made it worse. Higher speed would most probably mean higher disc loading. Can't see what difference being out of balance (which I can't see evidence of) would have made either.

It normally takes about two seconds for the load to ease and hydraulic assistance to be restored. However, be aware that if the pilot is fighting the controls when this happens, the force being applied to the controls could result in an abrupt undesired opposite control movement.

Many of these accidents have happened while aggressively flying the helicopter at low altitudes, leaving very little time to recover. Most important for avoiding this kind of accident is to follow the aircraft limitations published in the helicopter’s flight manual.
aopa

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Re: French Helicopters

#40 Post by Seenenough » Wed Jul 01, 2020 5:01 am

Take off,move forward ,get to 60kts and 500 ft agl (to avoid of the dead mans curve) ,straight and level, into wind before turning was what I was taught.

I doubt he was even close to 60 and he looks to have been no higher than about 2 or 300 feet before he went into his steep turn.

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