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yellow5

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Greetings fellow Hawker drivers...

 

This is a great addon. Very cool in many ways. The only issue I am having when hand flying is my approach speed. Is there an average speed I should shoot for when crossing the threshold? I seem to carry too much speed and float down the runway. To slow and when I cut the power I slam onto the runway. Granted speed will vary based on weight, air temp, airport altitude, etc. In this case I am just looking for an average of what works. Any tips for setting up approach would be beneficial as well. For example when I set up my ILS approach, what speed should I be at when crossing the IAF. Then as I make the approach speeds at which to add flaps, gear, etc.

 

Thanks all,

 

Kevin

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It is quite helpful, provided one already knows what speed Vref is... :rolleyes:

 

The only absolute speed provided is that the a/c should be Vmin of 160 kias at the entry to the downwind leg.


Fr. Bill    

AOPA Member: 07141481 AARP Member: 3209010556

Interests: Gauge Programming - 3d Modeling for Milviz

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It is quite helpful, provided one already knows what speed Vref is... :rolleyes:

 

The only absolute speed provided is that the a/c should be Vmin of 160 kias at the entry to the downwind leg.

 

I should have probably added that this is for the VFR approaches. There is another diagram for IFR approaches. I can post it, if someone has interest for it (and if this does not constitute any infringment of copyrighted material).

 

As far as Vref is concerned, I am trying to "figure it out" based on observation mixed with rough calculations:

http://flightaware.com/live/aircrafttype/H25B/L

 

The last radar sweeps for these birds at about 700-1100 feet (which I assume to be "in final") mostly return a G/S of about 125-126 kts. In the approach phase I mostly see a G/S of about 160 kts. For the moment I try to set a Vref below 125 kts, with a very rough aproximation. I never crashed so far :-)

 

I hope that Jim Barrett will chime in, he appears to be the most qualified Hawker expert here.

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In the documents folder for this plane is H850XP Performance Tables.pdf

 

Starting on page 3 are a series of tables that specify the V1/Vr/V2 speeds, final take-off speed (Vfto), enroute climb speed (Venr) and one you are looking for which is the reference speed - Vref.

 

This is generally 1.3 times the stall speed IN THE LANDING CONFIGURATION, and depends on the weight of the aircraft. The approach speed is Vref plus an appropriate additive, or none at all. Some operators specify  adding the gust only, others 1/2 the headwind and all the gust, or 1/3 of the headwind and all the gust, etc. and is what you are aiming to be stable at on your final approach. The diagram posted above shows Vref + 10 on final reducing to Vref + gust factor.

 

Example: at 23,000 lbs, Vref = 126 kts.  Landing on runway 05 at Nampula (FQNP), Mozambique, the wind is 110/20, giving 10 kts headwind.

 

Vapp = 126 +10 = 136 kts reducing to 126 kts when approaching the threshold and landing is assured, .

 

If the wind is 110/20G40 i.e. gusts of 20 knots, then the gust factor = the headwind component of the gust which is 10 knots. Approaching the threshold and assured of landing, Vapp now = 126 + 10 ( gust factor) = 136 kts.  We calculate these speeds for every approach and landing.

 

Quite often there will be a limit to the additives. Typically I have seen 15 knots maximum over a variety of aircraft and operators.

 

If you were doing 160 kts at this weight you would float quite a way eating up valuable runway before touching down and run the risk of running off the end at certain airports. Conversely, doing 110 is cutting down your buffer above stall speed (97 kts), and further reducing the effectiveness of the controls, requiring a deeper flare than usual to avoid a hard landing with the added risk of a tail strike in some aircraft.


Christopher Allan

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