ORIGINAL: CrateCruncher
how does reducing incidence <u>with respect to the horiz. stab</u>, reduce the engine downthrust angle?
Downthrust effectiveness is a result of propwash hitting the bottom of the stab?? Wow! Can you link us to a reputable source which supports this? Why do rear engine canards use upthrust when there is no stab behind the prop?
Please help me understand this new science which you've come to sharewith us!
You missed his point. Most people miss the point that changing a wing's incidence isn't just doing one thing.
Most of these discussions really are about shimming a wing. That very often does reduce some trainer's tendency to climb with increased power. And that's pretty much what was the basis of his discussion.
There are THREE important lines that matter (thrust, wing incidence, and horizontal tail incidence) and when you change one of them you're effectively changing more than one relationship. And that's his (and many others) point.
If we change the AOI of the wing, we very often are changing both the thrust line and the tail's AOI because the wing goes to it's needed AOA no matter what.The wingis the player in this game that has all the power.It decideswhatAOA it needs when yousteer you model into the approach and adjust the throttle to get the speed you think is right. If you've suddenly adjust the AOI for that wing and then flown the sucker,that wing is still going to assume the AOAit wants to give you the approach you'redemanding once again. If you're flying that modelat the same speed as usual, that wing is going to assume the AOAit has always needed for that speed. And since it's at a newAOI on thefuselage, the fuselage is going tobe at a new AOA, and the stab and motor aregoing to have new AOA's as well.
Also, change the AOI of the wing and it'sdownwash is going to findthe stab at a different place than before. And the downwash is going to hit that stab at adifferent angle. Not much different, but differentnone the less.
He's sharing with us what a whole lot of people alreadyknow.