Viper Question
 

Hi All!

Does anyone know whether BVM Viper wings have a "sawtooth" notch in the leading edge.. I have a set that are already covered and was wondering if they were custom made or came like that from BVM at any time..

To elaborate.. the chord of the wing goes down from root to tip but jumps up a bit (like some fighter jets) at a point approximately midspan of each wing panel.

What effect does this have on the flying characteristics..


thanks, Jim

Viper Question
 

jiminy,
I have a BVM viper that is very old. It does not have a "sawtooth" notch in the leading edge. However, as I recall the newer versions of the viper did in fact have the the sawtooth notch in the leading edge of the wing.

Mine is the very old version that does not have a hatch in the nose. I think that the newer ones also had a hatch up there as well.

As far as flight characteristics, I remember hearing a long time ago that these new wings help low speed performance but it's been a while and I might not be remembering it correctly.

Hope this helps,
Randy

Viper Question
 

If I remember correctly, didn't BV offer a set of optional "Droops" that could be added to the wing? Maybe the sawtooth you have is a set of the leading edge droops??

Craig

sawtooth
 

Hi Jim:

My Ultra Viper has no such change in the leading edge line. As Craig pointed out BVM used to offer an attachment for the leading edge called "droops" that were supposed to enhance the stall characteristics of the wing.

Presumably on the Viper they caused the outer portion of the wing to have a steeper angle of attach than the inner portion. That way the outer portion of the wing would stall and stop producing lift while the inner portion would continue to produce lift and retain control authority. Just thinking out loud for a second, it's hard to believe that the Viper would benefit from these devices since the AOA with flaperons in the landing configuration must be steeper than the outer wing even with the droops, but I don't know for sure and would certainly defer to an aerodynamic engineer for the last word. As I think through the alternative, it may make more sense for the outer portion of the wing to "keep flying" while the root alternates between stall and producing lift. This would allow the flaperons to continue to function for roll control.

Anyhow, that's my long winded way of saying that the droops were intended to improve stall characteristics.

Antony

Viper Question
 

Anthony,

Adding area to the leading edge of a wing, as with the droops, does increase the stability during slow speed operations. The droops actually do three things... one, they add area to the tip of the wing. Two, they induce an aerodynamic washout to the tip. Especially if the leading edge of the droop is forward and below the leading edge of the wing. Three, again if they're forward and below the leading edge, they create an undercambered cross section at the tip. All of these benefits aid in allowing the tip to continue producing lift at high AOA's, even as the root has reached and passed it's stall angle. Take a peek at an airliners leading edge during take-off and landing. The entire wing morphs into a huge undercambered high lift structure.

Craig