RCU Forums - View Single Post - Engine right thrust-why?
View Single Post
Old 02-10-2006 | 06:18 AM
  #31  
mesae's Avatar
mesae
Senior Member
 
Joined: Dec 2002
Posts: 569
Likes: 0
Received 0 Likes on 0 Posts
From: Edmond, OK
Default RE: Engine right thrust-why?

ORIGINAL: Espresso-Outfitters
...Can you elaborate upon this, I'm in the mindset of basic physics here, you are displacing the volume of molecules outward, causing them to be less dense within the traveling path of the blade, now within it's absence they equalize out due to the natural air pressure, then do the same yet again on the returning cut into the air, I'd think the longer the interval in between cutting the air and allowing it to reintigrate back into it's orignal configuration the more adventagous. I'm sure after enough velocity of the actual prop assembly moving foward, the volume of air molecules pushing into the field make up for this effect.
This interval and reintegrating you write about doesn't occur. The action is continuous.

Before everyone starts arguing about this, might I suggest that all interested parties carefully review the following trustworthy link?

http://www.grc.nasa.gov/WWW/K-12/air...ropeller.html# (click the link to "fundamentals" where it talks about momentum theory)

It might avoid some unneccessary argument.

Detailed propeller theory is so complex that to argue about anything other than generalities requires many specifications.

Momemtum (or actuator disk) theory is a good first-order approximation but to go beyond that in terms of accounting for the many losses, requires specialized training. It's well worth the look-see though.

As far as being able to quantify thrust from a prop, the above theory is about as basic as you can get.