Re: ELIPPSE Propeller Article


ryan goodman
 

Ah, yes Dave Gall and I have done quite a butt if chatting. He seems like a very passionate and knowledgeable guy. I've really enjoyed talking with him. 


On Mon, Sep 11, 2017 at 5:42 PM, qplustwo@... [Q-LIST]
wrote:
 

Figured I would start a new topic to avoid cluttering up the forum.

There is a "reprint" of an EAA Experimenter article written by Paul himself available at http://rexresearch.com/lippsprop/lipps.htm. That article actually has my all-time favorite propeller quote in it: "Who uses static thrust? Airplanes are meant to fly, not pull tree stumps!"

Ryan:

As a fellow engineer, I can offer my zero cents worth on some aspects of Paul's work, since I've never carved a propeller hung on an airplane. I think the two most important things Paul did were 1) Using actual propeller theory to design a propeller for HIS particular airplane and 2) Using post-1920s and laminar flow airfoils with proper Reynolds Number and Mach corrections. Any "errors" he made from classic propeller theory were actually his own personal design choices, which I won't fault him for (spanning the elliptic lift distribution across the hub, ignoring fuselage effects). However, every homebuilder should take to heart his lesson on propeller "pitch" that's in that article!

[Side note: I got dragged into propeller design by a chance meeting at Airventure 2012 with Dave Gall (yes, THAT one) while he was busy creating a propeller of his own. The high speed, high RPM, and low HP of the Q2 mean you can throw away a significant amount of engine power in a hurry with the wrong prop!]

-MD

Join main@Q-List.groups.io to automatically receive all group messages.