I was wondering if you folks could enlighten me on the subject of tapered wings. I hope you can all excuse me for probably being a little ignorant when it comes to design but building a tapered wing for a homebuilt to me seems like it lacks any real benefit. Part of my ignorance stems from my lack to fully understand some of the charts and what not. Iíve been spending each night trying to work through the math of airfoils and wing plan forms but it seems to be coming a little slow.
As some of you know I have decided to build my own version of a Tipsy Nipper and with just the basic reference drawing done the wing is the next area of study. The original wings are tapered and from what I have learned so far the airplane is quite wonderful for aerobatics. Some searches online have revealed that many aerobatic monoplanes use some sort of taper in the wing.
On my version Iíve been thinking about letting aerobatics play second fiddle to everything else on the plane. In an ideal world I would like the airplane to be a good all around airplane that handles fairly well and is capable of simple aerobatics.
When researching tapered wing plan forms I just canít seem to figure out why people want to build taper into wings. Every bit of information I have found has made me conclude that the typical Hershey bar wings actually make for a great wing. Based on my reading here are the only benefits I have found so far for using a tapered wing for a homebuilt.
1. Lower drag
∑ Helps with overall speed
∑ Better lift distribution
2. Improved Maneuverability
∑ More structurally efficient with root.
∑ Lighter overall structure
From my perspective this seems to be great but upon reading, looking and studying a host of airplanes with Hershey bar wings it seems that normal Hershey bar wings can very well have low enough drag, great maneuverability, and structurally they can be built just as strong. Now, I realize some of the larger any faster airplanes out there may have a strong case to support the tapered wing plan form but for basic moderate speed homebuilt I have found some real problems with tapered wings. Iíll explain what I have discovered.
Working backwards here Iíll first talk about my thoughts on weight. I realize everyone in the realm of aviation works to avoid weight but realistically it seems to me that an airplane must have a wing and any wing regardless of type weighs a certain amount thatís simply unavoidable. So right off the bat a designer knows that if a Hershey bar type wing weighs ď X ď than a tapered wing should be less than ď X ď. OK, from my calculations the difference in weight on a tapered wing canít really amount to much, especially when you consider the extra time involved in creating a taper vs a simple rectangle. In order to create a tapered wing the wing has to be larger ( scale effect ) thus creating an increase in weight, cancelling out the overall difference.
The second point is structurally. Spending time studying airplanes made in the last 30 or so years makes me wonder whatís wrong structurally with a rectangular wing plan form. I am really having a hard time buying into the fact that the difference structurally between the two wings is worth talking about.
On the topic of maneuverability airplanes like the RV series or any type of airplane in that class has pretty darn good maneuverability all things considered, and all have straight wings.
I can understand why designers like the tapered wing as it concerns lift distribution but at the same time along with lift distribution come the fact that tip stall also comes with the territory, and since ailerons just so happen to be mounted on the tips of the wings they also can loose effectiveness and potentially the airplane can end up in a spin.
On the topic of speed, again I fail to see any advantage here because speed is relative to so many other factors that the overall percentage of benefit that tapered wings have with speed is rather small.
Could anyone tell me if Iím on to something here, I have tons more reading to do on this subject so I could be way off base in my thinking but so far I see nothing wrong with a basic rectangular wing. Mike