RTTL |
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Barryg
Newbie Joined: 24 May 2007 Location: United Kingdom Status: Offline Points: 24 |
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sorry everyone, slip of the finger or I need glasses, that should have been 2751
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Coelacanth
Newbie Joined: 17 October 2007 Location: South Africa Status: Offline Points: 5 |
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[QUOTE=Christian]
The displayed speeds conversion from knots is way off, 39 knots is more like 72 km/h or 45 mph. In truth they were capable of more like 50 knots under ideal conditions. Indeed, and 530 nautical miles converts to 981km!, not 740! |
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Rob
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cofrada
Newbie Joined: 25 September 2006 Location: United Kingdom Status: Offline Points: 17 |
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I served on 2754, 2758, 2768, & 2771 the fastest we went on any of these boats was a touch over 40kts, fully fuelled (2220 galls of AVGAS) and fully kitted, they may just touch 40kt but more like 35, and that's including over-riding the govenors. The only RTTL that I know exceeded 50kts was 2772E but at the time she was of different construction to the other 'TTLs. When 2771 was slipped after re-decking in 1969 or 70 she achieved 44kts, on trials that was a s fast as I have ever been on a RTTL, antother reason not to exceed the "laid down " maximum revs for the Griffons was fuel consumption, if they were wound up to 2400-2500 rpm the fuel consumption would exceed 200gph per engine. We did fell a responsibility to the British Tax Payer. |
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tramontana
Senior Member Joined: 06 April 2007 Status: Offline Points: 418 |
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Apparently 2772E may have also had "sprint" engines fitted or certainly tuned Griffon's, as to how long they remained in her I do not know it may have been only for the time Vosper were "showboating" her. She appears to have had a "G" meter fitted at one time do you know anything about it?
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rafwebfoot
Senior Member Joined: 15 May 2007 Location: Scotland Status: Offline Points: 111 |
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Hi Folks, 'G' meters were fitted to RTTLs for progressive trials and testing. With reference to fuel consumption:- RTTL 2757 recorded the following on 30/1/57 with a half load of fuel and displacing 31.25 tons. RPM &nb sp; SPEED & nbsp; GALLS/HR &nbs p; RANGE 800 &nb sp; 10 &nbs p; &nbs p; 32 &nbs p; &nbs p; 650 1200 &n bsp; 16.5 &nbs p; &nbs p; 57 &nbs p; &nbs p; 615 1600 &n bsp; 25 &nbs p; &nbs p; 90 &nbs p; &nbs p; 595 1800 &n bsp; 30 &nbs p; &nbs p; 108 & nbsp; & nbsp; 575 2000 &n bsp; 33.5 &n bsp; 13 0   ;   ; 545 2200 &n bsp; 36.5 &n bsp; 152 &nb sp; &nb sp; 500 The range was based on usable fuel capacity of 2100 gallons ( total quantity 2220 gallons - 95% full). This was with a new dry boat. If I recall corectly we worked out average fuel consumption at 180 galls per hour. |
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FAIR WINDS AND A FAVOURABLE TIDE
Donald |
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tramontana
Senior Member Joined: 06 April 2007 Status: Offline Points: 418 |
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Were the G meters used to measure acceleration or bow lift as there was a certain amount of G felt on a powerboat when the bow lifted as I remember, but I don't remember if it was ever measured.
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rafwebfoot
Senior Member Joined: 15 May 2007 Location: Scotland Status: Offline Points: 111 |
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The 'G' force meter (or accelerometer) was calibrated before and after each trial run by rotating them axially through 90 degrees and then 180 degrees from their normal working position. This gave positions on the recorder trace of +1g - 0 - and -1g respectively. The normal force of gravity equivalent to 1g acts first in one direction and then the other on the meter. They measured the slamming forces acting on the hull across the full speed range and varying sea states.
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FAIR WINDS AND A FAVOURABLE TIDE
Donald |
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tramontana
Senior Member Joined: 06 April 2007 Status: Offline Points: 418 |
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Thank you for the explanation Donald, has there been any pictures of 2552 in her present condition been made available yet? Great article in the A.S.R magazine re Torry, great memories of the area post war, the chap stood up in the front turret of 118 was Ron (Mick) Butler who died around 3years ago, he was a really nice chap with some good stories of the A.S.R.Service.
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barnacle
Groupie Joined: 16 June 2007 Location: United Kingdom Status: Offline Points: 69 |
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stumbled across this on my travels
www.time-capsules.co.uk/picture/number482.asp Edited by ForumManager |
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barnacle
Groupie Joined: 16 June 2007 Location: United Kingdom Status: Offline Points: 69 |
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Hello folks.
Long time no post on this forum.. The films that I mentioned many posts back are available on a DVD The films are "The Royal Air Force Afloat" (1972 29 mins) and "State of Readiness" (1970 2 mins) and "Sea Survival with the RAF" (1970 2 mins) Both are available, with other RAF Training films, on a 2 DVD set from Amazon titled "the Royal Air Force in the early 1970's"
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