Help required on Super Puma fuel consumption...

[Prawn2king4]

Hi All,

A friend of mine is writing a novel and would like some info.

It's a while since I flew the S Puma, but I know the average fuel consumption is around 950 lbs/hr, but I don't have access to the manuals any more.

The specific question is with 400 lbs remaining in flight, (which would give around 25 mins flying) and if one of the engines is shut down or pulled back and the fuel for that engine transferred to the good engine, what additional flight time can be gained?

I know there are variables, but let's assume still air conditions.

Any help would be appreciated. Thanks.

[toptobottom]

That's going to be one hell of a novel... :8

[SASless]

It's been done in real life...so not fiction....maybe not in a Super Puma but in a Wessex and Chinook for sure.

[drakkar]

950 Lbs/hour seems quite optimistic to me.
On one engine, as I remember, the fuel consumption is around 11 Lbs/min
I let you make the maths

Cheers

[Colibri49]

Super Puma fuel consumption for planning at average weights, at twin engine cruise of 130 knots gives a safe average consumption of 1030 lbs/hour.

From the tables for single engine fuel consumption I've selected at high-ish weight 18500lbs, 3000' altitude and intercontingency(continous) power, 115 knots giving 740 lbs/hour.

3850 in tanks at take-off less 400 remaining at end of flight leaves 3450 usable:

Twin engine endurance in cruise 3.3 hours x 130 knots = 435 NM range

Single engine endurance " " 4.6 hours x 115 knots = 536 NM range

So another 100 NM possible in still air, which would take 52 mins at 115 knots.

[TipCap]

Tell you what, the 332's I used to fly didnt give you 130 kts. Thats what we were told to plan on by commercial but in reality 120 - 125 kts if you were lucky but I will give you 1030 lbs/hr.

;)

[Squeaks]

The specific question is with 400 lbs remaining in flight, (which would give around 25 mins flying) and if one of the engines is shut down or pulled back and the fuel for that engine transferred to the good engine, what additional flight time can be gained?

I know there are variables, but let's assume still air conditions.


I suspect that discussions on twin engine burn isn't what the OP is after! Just the extra flight time (endurance) that is available with 400lbs remaining?

400lb Normal endurance to dry tanks would be 23 minutes, AEO 1030lb/hr
400lb Endurance to dry tanks, OEI would be 33 minutes 740lb/hr

Extra flight time would be 10 minutes.

[212man]

A certain German senior BHL pilot found himself in this situation in the early '90s, having found himself fogged out in the Beryl and left with no choice but trying for Norway (carried offshore alternate fuel!) I think the analysis was that the engine shutdown hindered rather than helped!

[TipCap]

I remember that incident

Althought I remember he thought he was heading for Sumburgh on diversion but turned the wrong way and realised that he didnt have enough fuel for it so was committed to Stavanger.

Mind you there were many "interesting" incidents in the early days which paved the way for safer operations in the long run.

[SASless]

One thing learned early on was to tote plenty of fuel for Mum and the Kids when operating out of Sumburgh or out of Teeside as it could get to be a long way between watering holes. Sometimes one even listed that MAK fuel....but not always.

Ever start your transfer from the external aux tank into the mains....to keep your onshore diversion fuel...but then forget to shut it off before pumping most of it overboard? Instant rethink of the flight plan at that point!

[Prawn2king4]

Thanks all, particularly Squeaks, who cottoned on to what I was after. Would have been simpler to ask for SE fuel burn I guess.

Don't know where I got 950/hr from, of course it's 1030 now I am reminded.

And yes, SAS, it's been done before - and on a S Puma; but not by me fortunately.

I'll pass on the info - maybe a good read...!

[Fareastdriver]

Don't ask me why but a 332 with sponson tanks on will go 5 knots faster than one without.

[arismount]

I know nothing about these particular machines except what I read. But responding to FED's comment about the increased speed to be had from a sponson-equipped aircraft...just looking at photos, it might be due to some lift obtained from the sponson body, and also the sponsons might re-direct airflow that could create a low-pressure (drag-inducing) region just aft of the cabin and below the tailboom in a machine without sponsons.
If guesses were dollars I would not be a poor man.