Nimrod, and RR Spey ...

[Terrorfex]

I've been pointed this way by some fellows over at E-Goat.

Would anyone happen to have the take-off speed of the Nimrod handy? A figure of between 122 - 135 kts has been bandied about.

More unlikely still, does anyone have an inkling for the diameter of the Rolls Royce Spey powering the Nimrod? I've been able to find a Jet Pipe diameter of .99 metres, but can't find anything regarding the intake.

Any assistance goes directly to making my number-crunching coursework that bit more accurate.

Cheers.

[kevnurse]

At 120,000lbs AUW, VR was 111 kts,
At 130,000lbs AUW, VR was 117 kts
At 184,000 lbs AUW (normal max permitted), VR was 142 Kts

Diameter of a RR Spey engine air intake at the engine is approx 1 metre; probably approx 1.5 metres at the wing leading edge, but I'm guessing from memory.

"AUW" is the total weight of the aircraft and everything on board.
"VR" is the speed at which the pilot pulls the column rearwards to get airborne.

Good luck with your course work

Regards
Kev

[Terrorfex]

Kev, that's of great help; especially the weights.

I've done a little more research and found a slightly more accurate assessment of the exhaust (jet pipe) diameter as being 0.83 metres. The ratio between inlet and exhaust seems a little small to me, but then again most of my previous calculations have been with newer engines.

[Fox3WheresMyBanana]

I remember the Nimrod/Spey coming up on my jet engine design finals paper in 1984!

[Terrorfex]

We were free to pick any aircraft and engine combination. Virtually everyone is going with something safe, like a commercial airliner and associated engine e.g. CF6. I almost went for the Phantom myself, but the addition of the afterburner made it a little too complicated for the time I've got left to number crunch!

[Herc-u-lease]

Spey - Rolls-Royce

I assume you found this already? Have you considered dropping Rolls an email asking? If you don't ask you don't get.

H

[pmills575]

Nimrod Spey at Gatwick Aviation Museum

If you are unable to find info via t'internet etc, we at Gatwick Aviation Museum have an ex Nimrod Spey amongst our engine collection. So I could be persuaded to measure the beast if required.

pm575

[Fareastdriver]

"VR" is the speed at which the pilot pulls the column rearwards to get airborne.

VR is not the take off speed. VR can be called up to 25knots before the actual takeoff speed.

[Gulfstreamaviator]

interesting use of the words TAKE OFF

VR is the rotation speed, ie at which speed a Pilot yanks the sticky thingi back, and hopes that beasti will get airborne.
So as mentioned actual take off speed is in excess of that number, and depending on several variable thingies could be very close or some distance away from that point.

sorry to be so technical.

gulfi

[Roland Pulfrew]

VR is not the take off speed. VR can be called up to 25knots before the actual takeoff speed.

So as mentioned actual take off speed is in excess of that number, and depending on several variable thingies could be very close or some distance away from that point.

To be very picky, the Nimrod did not have a calculated "take-off speed", only V1, VR and V2, so as Kev pointed out the the closest to the question asked is VR. A "take-off speed" for the Nimrod would be somewhere between VR and V2 and (without access to the relevant docs) I think that would be no more than 10 or 15 knots above VR - but I am sure Kev will be able to provide more info!

[thunderbird7]

Surely no thread about the nimrod and the Spey cannot be complete without:

"ninety-four-and-a-half-five-ten"

[Duncan D'Sorderlee]

98/560

Duncs

[ShortFatOne]

Button, air valve, rotation.......

[Terrorfex]

EDIT: Good old fashioned grunt work found a solution to the fuel flow quandry.

Appreciate all the help offered so far, though.

[OpsLoad8]

Or more likely, button, no air valve!

[QTRZulu]

Or for those of us with memories that go back a little further -

'Routine engine shutdown for fuel economy'

Now those where the days!

[Eminence Gris]

Spey fan diameter is 32 inches.

EG

[thunderbird7]

Bloody hell! This sounds like a GSU grilling thread! Now draw the fuel system...

[Party Animal]

and the number of holes in the airbrakes was?

and if anyone gets that right, what diameter was the holes??

[Sandy Parts]

A-cat question - activation weight of the spring-loaded flap in the toilet?..