ZE419, a Sea King HAS5 that (temporarily) forgot how to fly

[Pete in Lincs]

Ref colours, the arguments could go on & on & on....

http://www.network54.com/Forum/149674/message/1484854290/British+Desert+AF+P-40+Tomahawk+in+Jan+1942+should+have...what+color+Belly

But I like what you've done.

 

So there I was, around 1980 odd, Odiham, and used to wobblychoppers

with wheels wot taxied proper like, when I was sent out to marshall a Gazelle.

How the?/wot the? hover taxi??? I just made it up as we went along & he went

where I wanted him to, so that was good. That one had a shark on the tail too.

And a leaky tail rotor gearbox! The driver didn't like us poking around back there

so we went for tea.

 

AlexN, Many years ago I had a photo of a French Puma with a Fenestron tail rotor.

It looked most odd.

[Ex-FAAWAFU]

Assuming you mean Gazelle rather than Lynx...

 

I'm still not completely sure what you are asking!  The fenestron IS the tail rotor, so effect on it...?

 

It's a long time ago, but I don't recall there being any discrenable difference between the behaviour of a conventional TR and a fenestron from a purely pilot point of view.  Aerodynamincally speaking there are big differences - think about the difference between a ducted fan and a free turboprop, as an analogy.  

 

The biggest advantage of a fenestron from an operator's perspective is that you are less vulnerable to hitting your tail during a confined area landing.  In theory it's also good in high speed flight, but you may draw your own inference from the fact that all of the helicopter airspeed record holders had a conventional TR.  

 

The biggest disadvantage is that it is possible to stall the fenestron if you spot turn too quickly; the result is very much like a tail rotor failure, even though nothing mechanical has actually failed.

 

In short, there are pros & cons, as there are for all aerodynamic innovations; you don't get something for nothing.  The Gazelle is a lovely aircraft - a delight to fly, and an ideal trainer in that it's forgiving; easy to fly, but hard to fly well, which is exactly what you want.

 

But if I had to choose between a Gazelle & a Lynx, there is not even any hint of a contest.  You can do things in a Lynx that you'd never get away with in a Gaz.

Edited January 20, 2017 by Ex-FAAWAFU

[bzn20]

I didn't know you could stall a Fenestron, not surprising really, I never had any theory on them in training and anything to do with them after. Is it because it's "ducted" ,no tips in airflow ,  taking the easy route and not going through the blades ?

[Ex-FAAWAFU]

Hmm, well there you go.  I stuck "fenestron stall" into Google, and there is a very informative thread on PPRuNe Forums.   

 

This chap seems to have been an RN Beefer, I surmise, and he explains it very well.  Clearly this examination of the issue with Aerospatiale occurred after Muggins was a student, because we were definitely taught about Fenestron stall:

 

Having flown the Gazelle in a wide variety of flight regimes ..... and during a time where many pilots were coming unstuck with Fenestron related problems .......and during a time when some very telling tests were done with Aersospatiale using some Fleet Air Arm instructors. I have a few views and observations which would suggest that FENESTRON STALL is infact an excuse used to describe MISHANDLING,rather than a Stall of the blades. 

The term FENESTRON stall became obselete within the RN when - as a result of careful examination of circumstances surrounding the departure from controlled flight of a number of aircraft being flown by student pilots and some very experienced instructors at low speed or in the hover.  The Navy severely damaged several airframes as a result and felt compelled to look deeper into the problem …….. they visited Aerospatiale and carried out some extreme flight tests in the hover …….all captured on video and all VERY ALARMING to watch. The aircraft was put in a spot turn to the left and then allowed to continue to turn …… the rotation was allowed to accelerate and at a point where the rotation was becoming almost disorientating the opposite (RH) pedal was applied using FULL deflection. It caused a massive sustained overtorque but the aircraft rotation stopped (as I recall) within about 270 – 360 deg.   These tests were carried out at differing rates of rotation and different amounts of opposite pedal were used.  The final outcome illustrated that the aircraft is able to recover from a high rotational left turn but needed FULL APPLICATION of the opposite pedal. It would also cause a massive overtorque and was obviously therefore a flight regime to be avoided, especially by an inexperienced pilot.  

The RN then decided that the term FENESTRON STALL was no longer valid and the term YAW DIVERGENCE was born, which actually described the problem fairly well. The recovery action required from any apparent loss of control in a LH spot turn was to apply FULL Right pedal. If FULL RH pedal was not applied there was a risk that the aircraft might not recover and continue to suffer the YAW DIVERGENCE, which manifested itself as an increasing acceleration to the left.  By way of demonstration I used to show student pilots an incipient level of the problem:  
I used to sit in the hover into wind and I would apply 1-2 inches of RH pedal; the aircraft would yaw right and settle reasonably quickly within 20 – 40 deg of the into-wind heading (approx).  I would then return the aircraft to the i/w position and repeat the process with 1-2 inches of left pedal; yawing in this direction the aircraft would continue past the 40 deg point and begin to accelerate.  If left un-contained the rotation would continue to accelerate in a dynamic and unstable way.   I used to start recovery after 360 deg before any excessive yaw rate had developed. The demonstration was effective and illustrated the caution required in handling low speed left hand yaw applications.

YAW DIVERGENCE incidents were significantly reduced as a result of the increased awareness and if encountered were prevented by using the FULL application of the RH pedal. It is believed that many of the occurrences and incidents involving alleged F/STALL were in fact handling errors or misinterpretation the symptoms; and whilst many pilots believed they had applied FULL RH pedal it is considered likely that they never achieved FULL DEFLECTION in order to counter the problem. Many of the incidents were dealt with as if they had experienced a TR FAILURE – ie shutting the engine down . The subsequent high rotation – perceived as a TR FAIL’ and the ensuing EOL combined to make a mess of several airframes.

 

http://www.pprune.org/archive/index.php/t-20002.html if you want to read the whole thing.

[Ex-FAAWAFU]

Anyway, when a terrier eats something, it tends not to be recoverable.  Having scratch-built a skid (plastic tube of the right gauge, stiffened with wire inside it to give it strength and retain a shape), now it's time to move onto the missing starboard tail.

 

Luckily I have the port one to act as a good pattern, so it isn't complicated:

 

Shape now right, so all that remains is to give it a more aerodynamic profile and then drill some holes to attach both stabilisers with wire (the attachment point is tiny and wouldn't last 10 minutes just in plastic).

 

Sorry to invade Sea King land with a Gazelle; probably only a couple more posts, and then I will give it an RFI thread all of its own and leave this to Sea Kings alone.

 

More over the weekend - we're around this week.

 

Crisp

[perdu]

Will you be making a pair of those Crisp?

 

I have had similar issues with missing parts, sadly I no longer have a warmish dampish, very interested in anything 'dad' was doing, chap's jaw leaning on me at moments of leisure, but having undertaken replicating missing bits on several occasions I would warn ye sirrah that you need to make two, because no matter how careful ye are shape deviation can occur

 

Just a thought ye kens

 

Might even be the longest 'almost a sentence' I've written round these parts too 

Edited January 20, 2017 by perdu

[Ex-FAAWAFU]

Though I take your point, Bill, I think this is close enough for Government work...

 

I'll try to fix it them in place tomorrow.... on this:

 

Crisp

Edited January 21, 2017 by Ex-FAAWAFU

[woody37]

I never knew you could get a 1/48 Gazelle, that looks great

[Ex-FAAWAFU]

It's pretty old - a Fujimi offering, originally from 1985.  I obtained mine on EvilBay some time ago; I've finally found the WIP thread, which was as part of a Helicopter group build in 2013 

I'll take some proper photos in the next couple of days and post a proper RFI, but here she is restored to her full glory.  XZ938 / 45 of 705 Naval Air Squadron, Lt C P Morton RN first rotary wing solo, 21 October 1985.

 

Happy days!

 

And now back to the Sea King (& Bulldogs...)!

 

Crisp

 

 

Edited January 21, 2017 by Ex-FAAWAFU

[Brandy]

And Bulldogs to you too!

Though that is a great save on the old Gazelle...I'll have to look up my old log book from the ATC. It might be fun to do a Venture, my first solo: after 3 hours dual and with the engine shut down! Sounds much more impressive to those who don't know the Venture was a powered glider.....

 

Ian

Edited January 22, 2017 by limeypilot

[perdu]

She's a little sweetie Crisp, all credit to you getting her back on her little dainty feet

 

I have an Airfix Gazzle and its Navy Year here

 

I wonder

 

[Abandoned Project]

Attention to detail is an understatement!  I'm inclined to think it could fly when finished 

[TheBaron]

20 minutes ago, dadofthree said:

Attention to detail is an understatement!  I'm inclined to think it could fly when finished 

Such is the quality that some of us suspect he doesn't actually build these things at all but merely Photoshops real aircraft onto images of an empty bench.

[andyf117]

Content withdrawn - I will NOT be threatened by a moderator, simply because I queried the actions of another...

Edited June 27, 2020 by andyf117

[Ex-FAAWAFU]

Certainly looks like a powered tail fold; I have never seen anything like that.  In the bottom one, incidentally, you can see the hi-tech blade fold pole fitted - though quite what has happened to the tail itself, God only knows!

 

As it happens, I have managed to sneak a bit of time at the bench today, and I have been finishing off the Sea King cockpit in preparation for some big moments like buttoning up the fuselage; I need to get on and do that, because there's not that much more I can do without having sorted all the joints first.  Before I commit to glue, however, there is still a bit of work on a passenger seat inside the starboard forward window that is very visible from outside. Obviously, I also have to fit all the rear windows, too.

 

Anyway, the cockpit:

 

Since you last saw it...

- added starboard collective (scratch built from Albion Alloys tube, partly because the original kit part was eaten by the Carpet Monster, but also because the kit's lever didn't bear much resemblance to the real thing.  The port one is OK-ish, because the port lever is much simpler than the starboard - but the RH one was rubbish; the starboard lever has controls for the hoist etc., which are not replicated on the other side;

- added curly "pig-tails" for helmet comms (0.2mm copper wire wound round a drill bit);

- added the triangular off-white panels between seat and back (most visible in the top two shots).  I have no idea what function they are supposed to serve, but they are very visible on Brit seats;

- added the (Eduard printed) main instrument panel; you cannot see it in any of those photos, but the IP has wiring coming from the instrument backs - it will be visible from some angles through the quarterlights;

- put the pedals back (they'd fallen off while I was working on something else).

 

I now need to add one more tiny detail; RN Sea Kings have a little square folding panel on top of the coaming, just to the right of the Orange Crop controller.  This contains a list of the pre-set frequencies on the cab's radios, and is very visible from some angles.  Then I can finally call the cockpit done - I feel as though I have been working on it for ages, but I am pretty pleased with how it's looking.

 

More soon

 

Crisp

Edited January 28, 2017 by Ex-FAAWAFU

[bzn20]

I can't delete this !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Edited January 28, 2017 by bzn20

[bzn20]

4 hours ago, andyf117 said:

 

 

 

4 hours ago, andyf117 said:

 

So here I am, doing some work on a couple of my Sea Kings, in particular the folded tail on the HAS.1, for which I referred to the photo above - though I have no chance of emulating the excellent engineering work being done here, especially in 1/72.....

 

.....I'm also folding the tail on the HSS-2B, for which I referred to my own photo, below:

 

Spot the difference? It's the same on the CH-124:

 

But not on the US Navy UH-3H:

 

The only thing I can think of is that the Japanese and Canadian aircraft have powered folding tails because of use primarily from the small decks of frigates/destroyers, whereas American and British machines operated from carriers with room to walk around?

Probably right there Andy.....Thats a broken one.. Got oh dear written big ! Can't imagine how that happened.

 

Glad I wasn't there!

Edited January 28, 2017 by bzn20

[andyf117]

Content withdrawn - I will NOT be threatened by a moderator, simply because I queried the actions of another...

Edited June 27, 2020 by andyf117

[Jessica]

It looks as though the upper hinge bolt failed at some point, and the failure was discovered when the poor ground crew member unlocked the tail to fold it.

[bzn20]

Yes. I just zoomed it up again and the top hinge, the male lug  has failed. The bolt is still through the lug as it should be but no longer attached to the pylon. One bolt holding the  Pylon won't work. Bet he jumped !

[Ex-FAAWAFU]

Every so often something happens that means the modelling has to stop for an hour or two.  When you drop something quite large onto the floor, but still cannot find it to rescue it from the maw of the carpet monster, then you know your work space has been left un-tidy for too long.  So yesterday I spent much of the time clearing up, hoovering (oh yes - complete the CM's job for him) & generally making the Crisp-den marginally more habitable:

 

It also helps, as you get closer to some serious p[aint action, not to have a painting area full of fluff, dust, hairs and other detritus!

 

I also made a significant step forward in that the innards are now glued to one half of the fuselage:

 

A lot of careful clamping, alignment and measuring - @Martian's experience suggests that this kit can suffer from fit issues, so anything you can do to keep things straight has to help.

 

Then I started to move on to sorting out this visible seat back.  The thing I am talking about is this:

 

The rod at the back of the seat (which detaches for emergency egress - hence the black & yellow stripes - plus the blue seat back itself are both clearly visible from outside, so there has to be some internal detailing.  

 

A start, thanks to Air Scale's 'Modern Jet Cockpits" set.  (Sorry - iPhone focused on the wrong thing, it appears)

 

While I was doing that I suddenly realised that I have missed out the Coke Can (see earlier in the thread for a discussion of how this works - it is the emergency SACRU release plunger, which is protected by a red metal "can" at times when the aircraft is not load lifting).  Red outside, black & yellow top:

 

More soon

 

Crisp

[Ex-FAAWAFU]

...and fitted:

 

This photo makes it obvious that it is in fact made out of square rod rather than circular, but believe me you cannot see that with the naked eye!

 

C

[perdu]

I believe

I believe

Really, I've used optical illusoriness myself many a time

Alan Hall caught me though, years ago in Scale Aircraft Modelling in a report on that year's IPMS Nationals where my AEW Shackleton won class Bmod

"This modeller has drawn the creases on the blind with pencil, only an experienced eye could tell" saieth the Master

 

I do like the attention to unspoken detail, the yellowy window rail is perfect extra detailing

 

This blimmin thing will fly if you let it get a sniff of avtur

 

Love it!

[keefr22]

1 hour ago, Ex-FAAWAFU said:

This photo makes it obvious that it is in fact made out of square rod rather than circular, but believe me you cannot see that with the naked eye!

 

 

I think I can just about see it in the piccie....!! 

 

Coming along exceedingly well Crisp, really lovely detailing work going on!

 

Keith

[TheBaron]

1 hour ago, Ex-FAAWAFU said:

you cannot see that with the naked eye!

 

Posting such close-ups on BM is the modelling equivalent of exposure to the Eye of Sauron. What Keith and Bill say, so say we all.