PPRuNe Forums - View Single Post - An aerodynamics question (for experts only)
Old 12th Jul 2002, 02:52
  #1 (permalink)  
GoneWest
 
Join Date: Mar 2001
Location: Florida, USA
Posts: 632
Likes: 0
Received 0 Likes on 0 Posts
An aerodynamics question (for experts only)

I've tried this one before and got nowhere - maybe because it's all cr*p.

I've been looking through the books again following attendance at an instructor seminar - and am getting really confused with the "forces acting on an aircraft in flight".

Let's go for the easy option (or at least what I believe to be the easy option), let's take a light aircraft, in straight and level flight, all balanced - no acceleration, no climbing, nothing spectacular - just cruising along, drilling a hole in the sky. (first wanabee to send me £10 can log the time )

Trevor Thom, et al, are telling me that there are four forces acting on the aircraft - lift, weight, thrust and drag. And I've been using this since my trial lesson back in 1973.

Now, my FIC renewal has brought out the comments that we have been using the terms of the four forces for the sake of convenience but that actually there are only three forces. Weight, thrust and total reaction (TR). This TR can be broken down, by the scientists, to show a horizontal vector (not a force) which we call drag - and a vertical vector which we call lift.

I'm getting numerous arguments in favour of both camps. Anybody (who actually knows what they are talking about) care to comment? Please!
GoneWest is offline