Jodes

Hi Gentreau, thanks for your response!

I'm confident that I understand the principle of angle of attack versus attitude. So for example in a normal glide, the angle of attack will be steeper than the attitude.

The statement in question is in chapter 2, (page 31 in my version), under the subheading "The Mushing Glide" he says:

"There isn't room here to explain why a clean airplane can glide slightly nose-high, but it seems worth stating that it can do so".

I think I need to summarise some of his definitions in order to be precise about the aerodynamics of a nose-up glide; at least for me to refer to:

• "Chord is the line from the frontmost to the rearmost point of the wing section".
   
   
  
• Angle of attack is "the angle between the chord and the relative wind".
   
   
  
• Absolute angle of attack: "The angle that the no-lift line makes with the oncoming air".
   
   
  
• "[therefore] a wing can develop lift at zero or even at negative Angle of Attack".
   
   
  
• Angle of incidence is "the angle at which [the] wings are set with reference to the lengthwise axis of [the] airplane". (I don't know if this refers to the chord or the no-lift line".
   
   
  

So if I try to step through this problem:

1. Assume the aircraft is moving forwards. It will have drag opposing this motion.
    
    
   
2. For forward velocity to be constant, there must be a forward force opposite and equal to the horizontal drag force.
    
    
   
3. Assume that the fuselage and stabilisers and everything but the main wings create no forward force. (?)
    
    
   
4. Sub-conclusion: therefore, the wings must apply a forward force to the aircraft. (?)
    
    
   

I tried sketching a few diagrams of relative wind and lift. As per point (4), I conclude that the lift has to have a forward component.

If I then assume that lift is perpendicular to the no-lift line, then if the aircraft is nose-high (or even perfectly horizontal), I believe the lift would actually generate a negative horizontal component.

I'm digging a hole for myself here!!

If his statement about nose-up gliding is correct, and my arguments 1-4 are valid, then the lift is significantly forward of the no-lift perpendicular. Perhaps that's the quesiton I should be asking, but my brain is now stalled, this is going to need a lot of coffee to get my head round!!!

Hello!

Apologies if this is in the wrong forum section, I couldn't see a better one, please let me know if there is! Most of my interest is in topics similar to this one :)

I'm a total beginner, just starting to read the classic pilot's beginner book, "Stick and Rudder" by Langewiesche. He says it's possible to glide nose-up. I think he's implying that a nose-up glide can actually maintain forward velocity. How is this possible? (Is it?)

As far as my understand goes, there is always drag, which acts to slow the aircraft. And there is lift, which when the aircraft is nose-up, will not have any forward component. So without any thrust, I cannot see how there is any force to counteract the forces that would slow the aircraft.

Pls can someone tell me what I am not understanding here?

Thanks! :-)

I've always been interested in planes, amazing beautiful pieces of machinery!

I've been looking for somewhere to ask lots annoying questions which probably don't have an appropriate category :-p Hopefully I won't be too much of a nuisance! But I'm looking forward to talking with fellow enthusiasts :)

I'm interested in the practicalities of flying planes in general, and the basic physics behind it. I have a background in programming, and have a long term ambition of making a (vastly over-simplified) game-like 3d physics simulation of flying a model plane, ultimately to add circuitry to a model that can do things like take off and land automatically. Yes, this may take me decades lol!!! Truthfully, I don't expect to be successful but hey, it's a challenge! :-)

Thank you for taking me on board!