Wornout Rubber
Instead of being 'just another number' I could order a
Personal Title and be a bit different
Join Date: Jan 2008
Location: Dubai
Posts: 10
Best Glide Speed
Can anybody comment as to the best lift/drag speed (best glide speed), with Flaps 30 on a B.777?
The AAIB stated that the speed decayed to 108 Kts.
-----------------------------------------------------------------------
I asked this question to a flight test engineer. He stated for line pilots we could consider approach speed (Vref +5) to be close enough to L/D speed.
Holding speed on my a/c is 1.4 Vsi. Approach speed at Vref + 10 is approx. 1.4 Vsi(typical landing weight). Vref is 1.3 Vso.
Based on his comments, and the relationship of holding speed to Vsi, I'd think L/D is very close to Vref + 5.
We all know that L/D is not at, or even near, 1.0 Vso or 1.0 Vsi.
-----------------------------------------------------------------------
edit -
QRH lists best L/D speeds under 'Dual Engine Failure'. It's 1.5 x Vsi.
If that relationship (1.5x) holds with regards to Vso then L/D would be approimately Vref + 15-20.