Fuel Remaining Onboard.. HP7

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RAF_Quantum
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Re: Fuel Remaining Onboard.. HP7

Post by RAF_Quantum » 28 Jun 2008, 14:16

Hi,

One important thing to note regarding airspeed is that it it IAS that we see and not TAS. At higher altitudes the IAS decreases but the TAS increases so invariably on longer distance flights you will get there quicker at a higher altitude whilst showing the lower IAS. This is just for any newbs reading this that may think lower altitudes will make quicker flights as you 'go faster'.

Regards

John
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DaveB
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Re: Fuel Remaining Onboard.. HP7

Post by DaveB » 28 Jun 2008, 14:33

Hi John..

Yes.. that's very true and worthwhile to point out ;-) There are 'optimum' ranges where a higher altitude will prevail but this depends very much on the type of aircraft flown.. ie, piston prop.. turbo prop or jet. Something else to consider when flight planning ;-)

ATB

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fighterpilot
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Re: Fuel Remaining Onboard.. HP7

Post by fighterpilot » 28 Jun 2008, 19:07

Interesting, i was cruising at 9000 ft ith RPM at 14200 and trimmed to 730c. Maybe i was using a higher power setting at takeoff and climb but cannot remember my exact figures.

Richard
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simondix
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Re: Fuel Remaining Onboard.. HP7

Post by simondix » 28 Jun 2008, 20:50

Was Herald at Dyce with 46Kg on board the one I left there? if so I will rectify the matter.
Simon

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Re: Fuel Remaining Onboard.. HP7

Post by DaveB » 28 Jun 2008, 21:42

Hi Simon :)

Yes it was but don't worry.. I've topped them all up now. Just don't drag it down to 48kg and leave it again! :lol:

Richard..
I use 14000rpm for all Dart aircraft except the 748/780 and these I fly at 14200 :) I NEVER open the throttles full for takeoff as it's not required IMHO ;-) Therefore.. takeoff pwr is the same as climb/cruise the way I fly. If you're cruising at 14200.. this would definately explain your higher fuelburn though a tradeoff is that you'll be going a couple of knots faster than I do :)

ATB

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Re: Fuel Remaining Onboard.. HP7

Post by DaveB » 29 Jun 2008, 01:34

Hi y'all..

As a follow on to John's comment.. I've flown a quick flight this evening to highlight the differences between speed and altitude for those not au fait with what acutally happens.

Aircraft used was the HP7 and these are the recorded figures for flying at 6000ft and 9000ft/14000rpm in still air.
Altitude.....Fuelburn.....airspeed/groundspeed
6000ft.......836kgh..........200kias/216kts
9000ft.......803kgh..........194kias/219kts

Differential in groundspeed is 16kts between IAS and TAS (groundspeed) in the first example and 25kts between IAS and TAS in the second. Interestingly.. the difference between IAS at both heights is 6kts and TAS is only 3kts but.. you are actually travelling faster across the ground at 9000ft and using 33kgh less fuel. The decision you have to make is.. is it worth the extra time taken in the climb to travel 3kts faster (TAS) in the cruise while burning less fuel but having burned more to get there :lol: 14000rpm is relatively sedate for the Herald as max continuous is rated higher at 14500 with a recommended climb/cruise of 14200 but although your fuelburn will be higher.. the difference between IAS and TAS at those heights should be similar ;-)

ATB

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Viscount Cornbank
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Re: Fuel Remaining Onboard.. HP7

Post by Viscount Cornbank » 29 Jun 2008, 09:48

Hi Guys, :)

Thanks for tanking those up Dave, appreciate it :thumbsup:

You are free to do as you please of course, but the Herald has Dart 7 engines, and the normal cruise/climb power setting is 14200rpm/730'C, although the TGT figure can vary between individual mark numbers ;-) . 14000rpm is the equivalent figure on Dart 6 engines, ie Viscount 700/800,(not 810), F.27 mk 100 and very early HS.748s.

As a note, less than full power takeoffs were not permitted as the autofeather system only armed as full power was approached ;-)

cheers

Fraser
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Re: Fuel Remaining Onboard.. HP7

Post by DaveB » 29 Jun 2008, 11:50

No prob Fraser.. I enjoyed it ;-)

I hope I gave enough room to manoeuvre with the tankup's (taking into consideration I fly them - through force of habit - a little 'off peak').. I think I did as they're all in excess of 1000kg now.. some quite a bit over :)

What next.. Ooo.. maybe the Argosy fleet :think:

ATB

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simondix
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Re: Fuel Remaining Onboard.. HP7

Post by simondix » 29 Jun 2008, 18:37

DaveB wrote:Hi Simon :)

Yes it was but don't worry.. I've topped them all up now. Just don't drag it down to 48kg and leave it again! :lol:

DaveB :tab:
Sorry about that I get very parochial and forget I am not the only one who prefers flying north of the Watford Gap.
Simon

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fighterpilot
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Re: Fuel Remaining Onboard.. HP7

Post by fighterpilot » 07 Jul 2008, 18:30

A bit late i know but thanks for all he tips guys i think i will be a bit more authentic and use Frazers figures whilst flying the herald. One other thing i was thinking why not have a single thread stating the minimum fuel to be left in each aircraft?

Richard
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If you don't know where your going any road will get you there. - George Harrison

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