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Old 3rd Jul 2009, 13:20   #1 (permalink)
Probationary PPRuNer
 
Join Date: Jul 2009
Location: Germany
Age: 63
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Coffman Starter?

Hello!
Maybe some of you are able to identify following object:
Its a large blank Cartridge made of Brass with some Text engraved on the Bottom:
CART. ELEC. ENG. START No. 10 MK3 K. 71,2
The Dimensions are Diameter at Base with Rim: 8,2 cm
Diameter 7,2 cm and a total length of 18,3 cm...
In my opinion it might be a Coffman Start Cartridge for quite a big Engine!
I would appreciate if this item will be identified to an engine type or even an Aircraft.
Pictures are also available on demand!

Kind regards
Juergen Wittburg
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Old 3rd Jul 2009, 13:29   #2 (permalink)
 
Join Date: Apr 2003
Location: Lincolnshire
Posts: 2,121
Sounds like the standard engine start cartridge for a wide variety of aero engines.

Possibles:

RR Avon on Hunter
RR Avon on Canberra
Rover AAPP on Vulcan

Quite often, these were cleaned up after use for 'gizzits' for departing members of the squadron. Also used as desk tidies for pens & pencils etc.
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Old 3rd Jul 2009, 17:10   #3 (permalink)
 
Join Date: Feb 2006
Location: Chessington, Surrey
Age: 66
Posts: 347
Hello Juergen,

Avon 100 series. Plenty of a/c to choose from.

Stamped on the base of my "ornament" is : CART.ELEC.ENG.START No.10 MK3 B&SB 86 9. At some time it "fired up" an Avon in a Hunter T.7.

The "K" and the "B&SB" refer to the manufacturer I assume.
Can anybody suggest the names?

The "71 2" and "86 9" are probably the dates of manufacture.

Ciarain.
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Old 4th Jul 2009, 09:56   #4 (permalink)
Probationary PPRuNer
 
Join Date: Jul 2009
Location: Germany
Age: 63
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Hello ZH875,

many thanks for your quick response!
I never thought that this gas turbines were able to be fired up with a cartridge, even that large... Does anybody know the principle?
I worked with hydraulik start systems for Pratt&Whitney engines only in the late 70s.

Kind regards
Juergen Wittburg
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Old 4th Jul 2009, 10:41   #5 (permalink)
 
Join Date: Jun 2001
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JWittburg: photo here of a B57 starting, as you can see it was very smokey, and if the wind was in the wrong direction it was also very smelly.
The cartridge starting system of the B
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Old 4th Jul 2009, 19:15   #6 (permalink)
 
Join Date: Jan 2000
Location: sussex
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The object of the cartridge start was to allow the aircraft to be totally independant of ground services (electrics, air or hydraulics)

The cartridge case was filled with a slow burning charge of cordite - not the fast-burn charge of a projectile.

When ignited, the high pressure of the burn was directed to a turbine (about six inches in diameter) which wizzed round at about 50,000 rpm. This was connected to the engine compressor via a reduction gear and gearbox and retractable coupling (not unlike a car "bendix" drive)

Since the burn lasted about 5 seconds, it spun the engine up to a reasonable rpm and as long as fuel was delivered to the combustion chambers and the high-energy igniters worked OK, the engine started.

The early starters only had a single cartridge but later ones had three, so three attempts could be made to start without a re-load being necessary.

On later marks of Hunters the "cartridge" was replaced by a combustion chamber in which IPN (Iso-Propyl-Nitrate (liquid rocket fuel) was burnt.

Both - in my experience - were effective and reliable systems, although when the IPN one went wrong, it usually did so quite dramatically !

Interestingly, does the CAA allow these start systems on civil registered aircraft ? (I believe they ban Coffman starters on Chipmunks ?)
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Old 4th Jul 2009, 20:22   #7 (permalink)
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Coffman Starters

Sea Furies also had them, a 6 gun unit not dissimailar to service Chipmunks but bigger as they had to start a Bristol Centaurus, 14 cylinder radial, very impressive
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Old 4th Jul 2009, 22:42   #8 (permalink)
 
Join Date: Dec 2007
Location: manchester
Posts: 77
Coffman Starters

Way back in 1973 I was a civilian Flying Instructor at the Hawker Siddeley Flying Club based at Hawarden near Chester and the three Club DHC1 Chipmunks were fitted with Coffman starters which I understand was quite unusual,however these aircraft were orignally built there and the factory no doubt had a good working arrangement with the local CAA Office.
All starts were therefore spectacular by civilian standards and whenever we appeared in public endeavoured to produce a synchronised start ,per the Reds of that era, but Sods law usually applied resulting in a misfire thus spoiling the effect.
On one occasion I taxied backin with the Tiger Moth and witnessed a fellow Instructor standing beside the raised starboard engine cowling of a Chipmunk ,he was resplendant in a Daz white shirt and endeavouring to clear a Coffman malfunction at which point the malfunctioning cartridge actually fired and he took on the slightly startled resemblance of a chimney sweep and furthermore ever so slightly deaf as a result !!
I understand that the three DHC1 Chipmunks were modified to electric starters when they were sold on, resulting in dimished Daz sales no doubt.

Last edited by midnight retired; 4th Jul 2009 at 22:50. Reason: spelling
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Old 5th Jul 2009, 18:56   #9 (permalink)
 
Join Date: Jul 2007
Location: norwich, norfolk, UK
Age: 65
Posts: 614
Coffman Starter Photo.

Today whilst visiting the Fenland and West Norfolk Aviation Museum with my 'personal guide' Richard Mason, a very nice and knowledgeable person, we came across this Coffman Starter exhibit, having read this thread and not knowing what they look like, I snapped a photo, Richard then showed me a second unit fitted to a recovered engine, which I 'think' was a merlin ???? I am sure you kind people will recognise the engine from what little is on view in my photo ????

Keith.



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