RCU Forums - View Single Post - Ed Kazmirski's Taurus
View Single Post
Old 12-03-2008 | 09:30 AM
  #795  
kingaltair
My Feedback: (4)
 
Joined: May 2005
Posts: 1,975
Likes: 0
Received 1 Like on 1 Post
From: Asheville, NC
Default RE: Ed Kazmurski's Taurus


ORIGINAL: WEDJ

Hi Duayne,

very interesting. What you call SFGs may actually be an attempt to reduce tail weight. Tip plates have the effect of increasing the effective Aspect ratio by reducing tip vorticies. So weight saved by cutting 3 inches of stab, but tip plates keep the effective tail area adequate.

Any Aero-engineers care to comment?
Is there a difference between reduced "tail weight", and just moving the C/G? I'm sure there is, but I don't know what practical effect it would have.

What you say is interesting since Ed DID make the stab-span in the Taurus II 3" longer than the original Taurus, (30 vs 27"). He may have been trying to get back to the original tail...but he could have more easily done that by making the new tail 27" again.

Before I made the decision to remove the "winglets" a friend and I closely looked at what Ed had done from all angles. The "tip plates" seemed to be canted in slightly, (slightly wider at the front than at the back). As Cees mentioned way back, we know Ed sought to have a CONSTANT SPEED throughout all the maneuvers...my friend took the winglet's angles to be a means to further increase drag for more constant speed on the downlines, but it is just speculation. Ed also originally wanted to do the same thing by designing the Taurus II with a very thick wing, (which we called the "Carrier Wing"..see above). That was the original wing he used on the Taurus II, and the wing he had with him as a backup to the 1963 "worlds", (there are FAI stickers on both the thick wing and fuse). Later on, for whatever reason, he decided to abandon that thick wing, and the Taurus II was converted to accept a standard airfoil Taurus wing. You can see the strips of balsa he used to fill the "thickness gap" on the fuselage. I guess what I'm trying to say here is that both the thick wing and thick stab were attempts to increase drag...he abondoned one early, and perhaps the other later on.

I DO know that he successfully flew the Taurus II (after a brief period with the Carrier Wing), with the standard Taurus wing, (with straight trailing edge), and its original stab, (without winglets) for several years because all the pictures we have show the standard enlarged stab. There are no pictures of the plane with the winglets. Other than it looking bad, that was the primary reason I chose to remove them.

The stab is coming along, and I should have some pictures to include in a few days. It's going to be difficult to make a perfect, seemless extension to the existing stab, but I couldn't leave it the way it was. Perhaps the smartest thing to do would have been to fly the plane with the winglets THEN make the change so I could compare flight characteristics, but I made the "executive decision" to do otherwise because I KNEW the Taurus II would fly well as it was originally flown.

One aside. My original King Altair had a 34" stab, (shortened by the builder to match the clipped wing). When I built my first "scratch built" King, I didn't "pick up" on that and built the stab full size at 36" while using the same clipped wing. I couldn't notice any difference, (but I'm probably not that good a pilot to be able to evaluate the difference; I'd probably attribute any difference to something else, the wind, or my own novice flying ability).

Duane
Attached Thumbnails Click image for larger version

Name:	Ca80317.jpg
Views:	62
Size:	263.3 KB
ID:	1083226   Click image for larger version

Name:	Lh18535.jpg
Views:	58
Size:	47.6 KB
ID:	1083227