Author Topic: "holy **** My Engines Gone!!!" (Read 2310 times)

dtango · « **Reply #30 on:** January 07, 2007, 09:41:45 AM »

Best glide speed occurs when an aircraft's lift-to-drag ratio is at it's maximum. This happens to correspond very closely to best climb speed (best rate of climb) which is the default speed for ALT-X in the game.

The speed for max L/D varies between aircraft owing to different lift and drag charcteristics of each aircraft. Your best bet is to reduce rpm (feather the prop as much as you can) and then hit ALT-X using the default speed in AH for the particular aircraft.

The default speed for ALT-X in AH is automatically set for each aircraft for the best climb speed of that aircraft. HTC will need to confirm but I believe this self adjusts based on the weight of the aircraft at that moment in time as well.

Tango, XO
412th FS Braunco Mustangs

Schatzi · « **Reply #31 on:** January 07, 2007, 10:01:22 AM »

Quote

Originally posted by Reynolds
Id say go for it. Until he posts a location, its actually a fair bet that english IS his first language.

Well, id say BET AGAIN.

hitech · « **Reply #32 on:** January 07, 2007, 12:42:41 PM »

dtango: Best climb rate is set for each plane, but does not change with different plane loadouts ,fuel, or altitude.

Best glide speed is normally very close to Vy, I.E. best climb speed and should be the same on planes with feathered props.

When you put prop drag into the equation , I havn't confirmed the physics just a gut guess, the best glide speed would be slightly slower than Vy.

HiTech

dtango · « **Reply #33 on:** January 07, 2007, 04:43:56 PM »

Ah, thanks for the clarification HT. I must be losing my braincells faster than I realize! Got confused with changes in rate-of-climb with different weights and forgot that velocity for best-rate-of-climb is constant no matter the weight.

Debonair- I just noticed your post. Here's a graph to explain the difference between Vy and Vbg.

The reason Vy just slightly higher than Vbg (or velocity for L/D max) is because piston engine prop plane power available doesn't reach it's peak until somewhere greater than velocity for max L/D ratio. I believe this is because prop efficiency doesn't reach it's maximum until higher velocities even with constant speed props.

On the graph Vbg would be at the lowest point of the PR graph, while Vy is where excess power is at max (PA-PR) which is further to right of Vbg in terms of velocity.

Tango, XO
412th FS Braunco Mustangs