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jhurditch
23rd Mar 2010, 10:38
Can anyone please give me some insight into the average fuel flow rates for takeoff and cruise for the dash 8 q400. Even better would be a mid cruise weight for a standard length flight.

Thanks

Piece of Cake
23rd Mar 2010, 11:37
Fuel flow rates for Take off can vary, the lowest reduced power take off setting (81% TQ) will be quite different from a Normal Take off (90% TQ).

Also for cruise, it varies if you use High speed cruise/intermediate speed cruise, also dependant on gross weight, ISA deviation etc.

For example at 22,000kgs at intermediate speed cruise, total fuel flow will be around 840Kgs/hr, at 28,000Kgs, high speed cruise it will be approx 1100Kgs/Hr.

Send me a PM if you want and I can look up the exact figures from the AFM later.

FlyingTinCans
23rd Mar 2010, 14:04
Peice of Cake's figures seem pretty accurate, as a rule of thumb on the line, 1000kg/hr for your average flight. (T/O, cruise, appr and landing)

jhurditch
24th Mar 2010, 00:34
Thanks mate, that helps a lot. The thing is I don't have any off the documents. Im doing A/C engineering at Uni and am trying to find the CL of the aircraft. Maybe you can tell me some more things if you are aware of them off the top of your head. What would your indicated airspeed be at your most average cruise altitude and most average cruise mode (i.e fast, intermediate, etc).

Cheers mate

Piece of Cake
24th Mar 2010, 22:20
Off the top of my head,

We cruise at FL240 or 250, the Indicated Airspeed will be around 245-250 knots, this gives a true Airspeed around 360 Knots or ~M.59. It varies a little bit on weight and ISA deviation. This is using high speed cruise, which we use most of the time unless we have good tailwinds or are ahead of schedule when we will then use intermediate speed cruise.

If you need any tech info on the aircraft systems

SmartCockpit - Dash-8 400 (http://www.smartcockpit.com/plane/bombardier/DASH-8-400/)

is a good website.

If you need anything else, just ask.

jhurditch
25th Mar 2010, 01:12
Thanks heaps mate, Could you by any chance tell me what a mid cruise weight would be on say, a standard flight. I just need average numbers, does not need to be precise.

Cheers

Coffin Corner
25th Mar 2010, 03:36
jhurditch

A mid cruise weight could be anything, so many variables due to passenger loads and fuel loading that any figure given would be arbitrary.

A simple rule of thumb would be a basic weight of 18,000kg, fuel anything from lets say 2,000kg to 4,000kg (you did say mid-cruise, and assuming we've burned some off already), and then a rule of thumb for passenger/baggage weights we use to guestimate what weight we'd be when tanking fuel would be for every 10 passengers you would have on board 1,000kg.

So for a flight with 50 passengers on board, fuel remaining of 3,000kg and a basic empty weight of 18,000kg you would have a cruise loading of

18,000kg
50/10 x 1,000 = 5,000kg
3,000kg

Total weight = 26,000kg

Hope this helps

G SXTY
26th Mar 2010, 12:34
I was bored enough to actually make a note of the fuel flow figures yesterday:

TOW around 26,000kg (so cruise weight around 25.5 ish), FL240, canít remember the exact ISA deviation, but it was quite unremarkable.

At Vmo Ė 10 (around 245KIAS / 350KTAS) with FADEC in climb mode, total FF was 1180kg/hr. With FADEC selected to cruise it reduced to 1120. Reducing to Vmo-20 typically reduces FF to just over 1 tonne/hr, and 900kg/hr is quite achievable if you go on an economy run.

Fuel consumption on the Q400 seems to be remarkably consistent. Itís not unusual to fly the exact same route twice in the space of a few hours, and for the burns to within 10 or 15kg of each other.

jhurditch
28th Mar 2010, 11:18
G SXTY, you are a life saver. Thanks for the efforts here.

On another note, do you find the aircraft to be close coupled?

Cheers

G SXTY
29th Mar 2010, 20:27
Could you expand the question? Sorry to sound thick, but I just drive it.

I find it a handful if that helps. ;)

jhurditch
30th Mar 2010, 13:31
I understand it to mean a number of different things. I believe structurally it described the distance from the main wing to the tail and how the inertial forced are thus created from this configuration. In more simple terms I take it to me how nice the aircraft feels to fly in terms of obedience in roll, pitch and yaw from inputs.

I suppose I am asking if the a/c is co operative or needs a fair bit of work on your part to do what you want it to aerodynamically.

Cheers

Coffin Corner
30th Mar 2010, 14:43
jhurditch

The Q400 is reasonably challenging to fly accurately manually, but by no means impossible (obviously), I try to keep the raw data and hand flying skills up as much as possible.
The pitch/roll couple is not in equilibrium, i.e. it is far more sensitive in pitch than it is in roll at high dynamic pressures where there seems to be alot of roll inertia, but a fair bit of pitch inertia at low dynamic pressures (slow; vref).

The yaw couple is the bane of Q400 pilots lives ;), any power change and there is a yaw change, the yaw couple is quite large and seems to vary from a/c to a/c, i.e. some are worse than others.

shaun ryder
30th Mar 2010, 15:25
Basically what he's saying is, is that it fly's as bad as it looks

;)

G SXTY
30th Mar 2010, 23:41
That's pretty much it.

Great engines, great fuel economy - handling can be interesting.

Clandestino
2nd Apr 2010, 16:39
it fly's as bad as it looks

I beg to differ.

She looks far, far better than she flies. She's quite heavy in pitch, difficult to trim (not impossible, though) and YD is a joke - rudder and trim is the way to play even with AP engaged.

Piece of Cake
2nd Apr 2010, 20:09
The old adage, if it looks right it flys right....
My wife says it looks like a stick insect and I think it handles like a tractor. ;)

What it does well is that it takes a fair amount of passengers, is relatively quick and uses not much fuel.

If you want to know what it is like to fly, here is a link to a flight test from flightglobal:

Quiet revolution-25/04/2000-Flight International (http://www.flightglobal.com/articles/2000/04/25/64860/quiet-revolution.html)

BarbiesBoyfriend
2nd Apr 2010, 22:02
An accountants' aircraft.

Not a pilots'.

I take my hat off to those who fly it.

Saw a Baboo one land at LCY the other day and I swear, I've never seen a more alarming (or rapid) pre-touchdown rotation.

'Orrible!:ooh:

G SXTY
4th Apr 2010, 10:34
Stick insect Ė I like it!

That Flight article neatly sums up the aircraft, and itís interesting that most of its deficiencies are immediately obvious on a quick test flight.

Shame really, as itís close to being a great aeroplane Ė if only Bombardier could have spent a bit more development cash on it, or better still started with a clean sheet of paper.

As it is, itís compromised both ergonomically - due to commonality with the earlier Dashes - and in aerodynamic and handling terms, courtesy of the stretch. Still, thereís never a dull moment flying it. ;)

jhurditch
7th Apr 2010, 13:40
Piece of Cake,

Thanks for the article. Very very helpful. Does this noise canceling work or is it a bit of a gimmick?

Piece of Cake
9th Apr 2010, 11:26
The noise cancelling (NVS) works up to a point. The first time I flew on the aircraft on a familiarisation flight before I did my training on it, I said to the cabin crew "I thought the Q400 was suppsoed to be quiet, is the NVS switched on...?" "oh yes" she said "let me show you what it's like with with it switched off..." The noise levels with it switched off are enough to make your ears bleed (almost). So it does work.

Having said that, compared to the other turboprop which I flew as well (328). The Q400 was noisier inside with the NVS switched on than the 328 which has no NVS at all. Also flew on an ATR 42-500 (as a passenger) recently and it was quieter then the Q400 as well. The Dash 8-300 is noisier though. (Don't know about the Q300 though as have never been in one).

The Q400 also has quite high noise levels in the flightdeck as the wipers create quite a lot of airflow noise aound them, and they sometimes make a strange whistling noise when flying through cloud.

Good luck with your uni course, if you need any photos of any bits of the aircraft let me know and I can email them.