What if

General Modelling Forum => General Modeling topics => The Idea Bank => Topic started by: McColm on July 28, 2019, 12:09:20 am

Title: Boeing ECH-47 Chinook AEW
Post by: McColm on July 28, 2019, 12:09:20 am
During the 1970's the Royal Navy carried out a study of equipping a helicopter or heliplane with a  airborne early warning radar as the replacement for the Fairey Gannet AEW.3,  although trials in the real world would be carried out on several Sea King helicopters but none were converted to the AEW role prior to the Falklands War.
 The Admiralty had looked at using the Boeing CH-47 Chinook for C.O.D. and for use in the AEW role with the radar fitted on a rotating arm either attached to the rear of the fuselage or on the upper tail ramp. The radome would either contract when stowed or be rotated inline with the fuselage of the helicopter.
 Plans to resurrect the Fairey Rotodyne  as an AEW platform were also studied but the jet pods fitted to the main rotor blades would have been removed  and a turboshaft engine or engines installed in the main stack.  The Napier Eland engines or Rolls-Royce Tynes would have been replaced with the Allison T56 turboprop to attract American or export orders.
 The donor kit during this build is the 1/72 Italeri  No:054 ACH-47 Chinook Gunship.  The Gunship parts removed as they will be used on the Airfix Fairey Rotodyne.  I think that I still have the Freightdog inflatable AEW radome,  not too worry I found the Airfix part including the rotating arm. BlackDog also supplies  resin improvement sets for the Sea King AEW and Chinook.
Title: Re: Boeing ECH-47 Chinook AEW
Post by: Scotaidh on July 28, 2019, 04:25:58 am
I always wondered why the radome was attached to the side of the helo.  It can't have been very heavy or it would have affected flight. so why not just attach it to the underside of the tail-boom behind the fuselage? 

If the fuselage would have then occluded too much of the radar window, then put the radar on a boom long enough to extend below the helo.  For non-use times - landing & take-off, ship-board, etc - just have the boom rotate up and aft on a simple pivot operated by a winch - powered or hand-cranked, whatever.

Does anyone know why the method used was chosen?  I'm sure they looked at all reasonable options before choosing the one they did.
Title: Re: Boeing ECH-47 Chinook AEW
Post by: McColm on July 28, 2019, 05:12:25 am
In the case of the SeaKing the radar came from a  BAe Nimrod which is big and bulky.  It was a quick fix solution during the Falklands War.
Some helicopters have the radar in a housing in the nose, others in a radome under the forward fuselage ,  and the Russians tend to have theirs on an arm attached to the rear loading ramp.
Title: Re: Boeing ECH-47 Chinook AEW
Post by: PR19_Kit on July 28, 2019, 07:31:03 am
IIRC the Navy wanted the AEW Sea Kings to be re-configured to standard versions when they felt the need, so the whole shebang, aerial and internal electronics, could be unshipped very quickly with the aerial attached to the door.

I expect Thorvic knows the story in much more detail though.
Title: Re: Boeing ECH-47 Chinook AEW
Post by: Weaver on July 29, 2019, 05:08:51 am
Any of the other mounting systems would, on the Sea King, have resulted in serious and non-reversable airframe modifications. Mounting it where they do means just cutting a hole in the (non-structural) side door and bolting the pivot bracket to the floor. It also keeps the arm as short as possible, thereby saving weight and reducing drag when it's deployed. Remember that the stowed radome sits behind the main gear pods, so it doesn't increase the width of the helo as much as you might expect.
Title: Re: Boeing ECH-47 Chinook AEW
Post by: Squizzaa on July 29, 2019, 04:03:31 pm
I vaguely recall the French Army having a radar for battlefield surveillance mounted on a Puma?, in the early 2000s. I just recall a fairly large "bar" antenna that rotated under the helicopter but would fold upwards behind the fuselage when not in use. Come to think of it, for how much it must have weighed, it was probably on a Super Puma.
Title: Re: Boeing ECH-47 Chinook AEW
Post by: kitnut617 on July 29, 2019, 04:11:51 pm
What you need is one of these   ;D

(http://village.photos/images/user/8f3973c9-3f0e-4b54-80e2-017121c0bf9f/1a277af0-d1eb-4a66-8cf7-a514889f1e51.jpg)

(http://village.photos/images/user/8f3973c9-3f0e-4b54-80e2-017121c0bf9f/a1c82ddc-85ab-4a09-b172-ee9176cd7eb1.jpg)
Title: Re: Boeing ECH-47 Chinook AEW
Post by: Weaver on July 29, 2019, 04:49:38 pm
I vaguely recall the French Army having a radar for battlefield surveillance mounted on a Puma?, in the early 2000s. I just recall a fairly large "bar" antenna that rotated under the helicopter but would fold upwards behind the fuselage when not in use. Come to think of it, for how much it must have weighed, it was probably on a Super Puma.

Orchidée:

(https://www.avionslegendaires.net/wp-content/uploads/images/dossier/Puma-Orchid%C3%A9e_SHD-600x423.jpg)
Title: Re: Boeing ECH-47 Chinook AEW
Post by: Squizzaa on July 29, 2019, 09:11:51 pm
That's the one I was thinking of Weaver.  :thumbsup: In fact, that's the very picture that came to mind.  ;D
Title: Re: Boeing ECH-47 Chinook AEW
Post by: PR19_Kit on July 29, 2019, 11:02:49 pm
Ah, I saw one of those quite close-up a few years ago.

My youngest brother lives in the South of France, about 35 miles north of the Spanish border, and he has a designated French Army helicopter landing pad in the middle of his farm! One day when I was there a couple of Pumas trundled in, one landed and one hovered at around 250 ft. (maybe 75 meters for him  ;D) and that one had this 'thing' folded up under the boom.

I wondered what it was, and now I know.  :thumbsup:
Title: Re: Boeing ECH-47 Chinook AEW
Post by: rickshaw on July 30, 2019, 03:39:14 am
Didn't the Swedes put a radar on their twin rotor helicopters, on the rear ramp for ASW?

(http://www.hottail.nl/basevisits/2004/0829-Ronneby/Images/Hkp4C-69-2.jpg)
Title: Re: Boeing ECH-47 Chinook AEW
Post by: McColm on July 30, 2019, 12:25:34 pm
The EV-22 Osprey had something very similar,  I'm not too sure if it got past the concept model stage  :banghead:
Title: Re: Boeing ECH-47 Chinook AEW
Post by: Dizzyfugu on July 31, 2019, 12:08:32 am
There's also the Ka-31 with a foldable antenna array under the fuselage and a semi-retractable landing gear:

(https://www.airforce-technology.com/wp-content/uploads/sites/4/2017/09/Ka-31_5.jpg)
Title: Re: Boeing ECH-47 Chinook AEW
Post by: McColm on July 31, 2019, 09:27:27 am
If the Mach2 Super Frelon kit was decent I might have a go at Whiffing that :banghead:
Title: Re: Boeing ECH-47 Chinook AEW
Post by: NARSES2 on August 01, 2019, 12:51:02 am
I'm glad you put WAS between Mach 2 and decent  ;)

Seriously is it that bad a kit ?
Title: Re: Boeing ECH-47 Chinook AEW
Post by: McColm on August 01, 2019, 11:42:11 am
I'm glad you put WAS between Mach 2 and decent  ;)

Seriously is it that bad a kit ?
If you leave out the roof of the cabin then the two fuselage halves fit together at the top but there is a gap underneath.  There's a lot of cleaning up to do,  a spare pair of main and tail rotor blades will improve your build.  The ramp doors are very thick if displayed in the open position,. The landing gear needs reshaping so a spare set of landing gear is needed. The fuselage windows are misty which is a good thing as you can't see a lot through them.  The cockpit canopy fits and is almost clear. The seats are a bit chunky but the cockpit instruments have some detail on them.
Parts from the EH-101 Merlin do fit as well as the MH-53.
There will be a lot of swearing during the build  :banghead: