Tandem vs. Side-by-side Ergonomics and Aerodynamics

[Jon Matcho]

I have always thought a C-III in tandem would be a pretty good configuration. Lots of room in front for gear and snacks. :-)

 

I think the Cozy III would be a perfect base for staggered seating 

[Kent Ashton]

I think the Cozy III would be a perfect base for staggered seating 

 

 

Well, to be honest, I don't think a C-III is very aerodynamic compared to a Long-EZ with the same O-320 engine.  The fuselage pinches in to Long-EZ dimensions after passing the front seats so it is a wider fuselage and less-aerodynamic shape pushed by the same engine.  The Cozy IV is a more pleasing shape--rather round and losenge-shaped.  Of course, it has to make a larger hole through the air but it does have 30 more hp and does it in a more refined way.

 

I was reading Jack Norris' book that a 100 foot cube of air at sea level weighs 76,000 lbs.  That amazed me.  Think of  the thrust required to move so much air out of the way!  Air is heavy!  I wish I had used a smaller canopy on my EZ project.

[Jon Matcho]

Well, to be honest, I don't think a C-III is very aerodynamic compared to a Long-EZ with the same O-320 engine.

No disagreement there. That 2nd side-by-side seat is expensive.

 

I was reading Jack Norris' book that a 100 foot cube of air at sea level weighs 76,000 lbs. That amazed me.

Same here, but that's 1,000,000 one-foot cubes, each weighing ~0.08 pounds. Still, interesting.

 

My dilemma is how to get Long-EZ performance and economy with side-by-side seating. So far my answer is the Quickie Q2 which does not appear to suffer as big a penalty moving from single to side-by-side seating as with the Long-EZ derivatives. Then again, I am likely wrong with that as well. Perhaps the Q2 has better economy only than the Cozys and E-Racers.

[Marc Zeitlin]

Well, to be honest, I don't think a C-III is very aerodynamic compared to a Long-EZ with the same O-320 engine.

I have found that COZY III's and Long-EZ's with O-320's have almost exactly the same TAS at the same fuel flows. The COZY III's are sometimes even a bit faster. The III is far more aerodynamic than the MKIV - Damon Meyer's COZY III (N22AZ) with a 160 HP O-320 has about 10 kts. on my MKIV (and Tim Andres, and John Dembs, and ....) at lower fuel flows. And there's nothing magic about that plane - it's just a nice, clean aircraft.

[Kent Ashton]

I have found that COZY III's and Long-EZ's with O-320's have almost exactly the same TAS at the same fuel flows. The COZY III's are sometimes even a bit faster.

That is surprising to me although I don't have any data to discount it.  I would think the smaller fuselage profile of an EZ would trump a C-III with the same engine, prop, wheel pants, etc., just through lower parasite drag.  OTOH, a C-III probably gets a little fuselage lift from the forward fuselage that an EZ doesn't have.

 

When I owned a C-III, it seemed that all the O-320 EZ folks were touting higher cruise numbers than I was able to get.

Edited January 16, 2015 by Kent Ashton