Hawker 800A Fuel Questions (LJ60 hourly burns as well)

[Stealthh21]

Those numbers are right on for .78 HSC. A touch more if you took off above 22k or so.

Yeah, thats where I fly it. You know at 410 how annoying that rumble is.

 

[Lead Sled]

I would recommend and altitude of at least 7000 ft in order for the fuel to properly evaporate.

Years ago when I was flying a Lear 35, we had one of their test pilots in recurrent. We asked him about the minimum altitude for fuel dumping. He mentioned that during certification they conducted high-speed, low-altitude passes down the runway and the fuel was evaporated before it hit the ground. True or not, that's what we were told.

'Sled

 

[Problow]

we see as low as 1100 up high and at .77 to .78 in the LR60

 

[TimsKeeper]

???

slightly off topic.....can anyone whose flown both the hawkers and lr55/60's speak to the comfortableness of the cockpit of the lr 55/60? For someone tall (6'4-6'5) would the lear be problem say compared to the hawkers?

tx in advance

 

[Raskal]

Typically we figure 1800# the first hour and 1400-1500 the second hour I have seen as low as 1100# per-hour at Fl430 cruising .78.

On high speed climb out we usually do 300 IAS then transition to .78 in the climb this still gives us 1500 FPM in the upper 30's.I have also seen .80 in the climb at 1500 VSI in the mid 30's

If we really want to get high fast we'll target 280 Knots and transition to .70 this usually gives us 4-5000 low FPM thru the 20's and 2-3000 FPM thru the high 30's

:laugh: For a minute I thought you were talking about the Hawker 800...I shot coffee through my nose when I saw .78 at 430, I only wish.

 

[GREAT LAKES]

Yeah, thats where I fly it. You know at 410 how annoying that rumble is.

Stealth,

Let the wings get below 900lbs each before going to gravity. No rumble.

 

[ultrarunner]

750 is better, in order to keep wing-fuel warm.

 

[Stealthh21]

Stealth,

Let the wings get below 900lbs each before going to gravity. No rumble.

I pretty sure I get the rumble at less then 900 lbs. but i am flying tomorrow so I will for sure try it!! Thanks for the tip!!

 

[ultrarunner]

It's all about weight vs. altitude vs. speed. And not about how much fuel is in the wings.

The 60 will fly a higher than optimal altitude because it's so over powered. And poorly designed, IMO. The 60 is simply a variation on a theme.

Anyway, you can easily see this when you look at the normal-cruise charts, in that at heavy weights and high temps the plane will operate an a higher inefficient altitude.

For instance, level off at 410 at isa at 23,000 lbs which essentially represents a gross wt. take off.

The card shows that 390 is most efficient, but 410 is also usable, but at a higher fuel flow. This is due to wing-ineffficiency at that wt./temp/Alt.

And when you push the wing, it yells back.

I have take off NUMEROUS times at gross weight, climbed to the appropriate altitude and set power for .775-.780 and everything is happy. No rumbling.

But because of the crappy design, this is a plane that requires some thought.

Had Marcel designed it, we'd climb right to 410 at any time and cruise at .84, but that's not the case with this home-build we call the learjet.

Oh well.

 

[LRvsH25B]

750 is better, in order to keep wing-fuel warm.

Ultra, would you mind going into a little more detail and explain what your theory is behind that. sounds like you'r eon to something and I'd like ot know more about it. Thanks and I look forward to hearing more.