NO: Tapers in Span/Width/Thickness

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NO: Tapers in Span/Width/Thickness

Post by C/F »

For the good of combat in a radical approach to stopping the arms race of design and speed and improving the dropout ratio, I propose that instituting a, "NO" tapers of the wing in Span, width and thickness as the cure all.

First off allowing tapers in a wing plan form is all about bettering the aspect ratio and improving the wing loading. This results in increased spans and thinning out wings and watching carefully how the drag versus the lift plays out. With a no taper rule the wings become shorter and fatter to get to the identical flight performance that exists in today designs, However to do that with a no taper rule on the wing, the drag will increase and speeds go down.

Low drag arms race in SSC has proven that the theoratical speed of a prop and rpm limit can be realized, giving a distinct advantage.

Think for a minute how many trainers, sport models and fun fly type designs employ the use of Hershey bar wings? with stall proof flight envelopes.

Think for a minute how wing span over the last 3 years has increased yielding a distinct advantage and requiring more specilaized materials and construction methods.

Think for a minute how many flyins or demos you would be willing to do with your finely tuned 72" contest model, yet at a recent flyin I attended a dozen local flavors of combat models came out of the trailers. Only 1 had a tapered wing and nothing in the 55" span, yet a great time was had. I did not even feel right about bringing out the "GO Devil" so I sat it out.


What is so fundementally wrong with this one simple rule that would not be a step in the right direction, other than I submitted it???
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Post by wparmenter »

I agree.

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Post by Jimbo »

Is that the cure all for SSC, Open B or Open A ?

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Post by wparmenter »

No. Combat needs a hot rod class. I think a spec class or at least a spec wing/prop/rpm limits could be the answer for entry level combatters using older technology. I would like to see limited b become more of a spec class as well, but that does not appear to be the general consensus of the members responding to limited b questions. I am just voiceing my opinion. I do not have the desire to champion a spec class either.

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Post by Devil Dog »

I’m not sure if it would be a cure all, but it would definitely be a step in the right direction. If it included wing span and foil, I would support it.[:)]
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Post by wparmenter »

The only problem I see with airfoil limits is it essentially eliminates any SPAD designs. I bet C/F saw a bunch of coro planes coming out of trailers. We see coro planes here in missouri, but they are in the .40 through .46 size.

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Post by Hat Trick »

I agree in theory but I think it would be difficult to pass politically! I would be happy with a wing area and span limit. Then you could use square or whatever you want. The square wing might even prove out to be better.
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Post by Jimbo »

Sheepy take a look at the RCHangout.com site, I could use your advice or any results on testing you would like to do for that class.

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Post by sgilkey »

Mike F, you're right, the problem with your proposal is that you proposed it! JUST KIDDING. Actually I like it, and, like Cher, if I could turn back time, I'd go for it. A part of me still wants what you suggest. I just hate to see all the plane inventories, and kit offerings, obsoleted. And no-taper, hershey-bar wings haven't done much to limit speeds, technology racing, and costs in Q500 airframes. heck, look at record times for Q500 vs. Quarter 40, not that much different, plus Q40 gets to use a toothpick prop and a big venturi and 26k+ rpm! I'd love to see everyone flying hershey bar wings, including me and Brian, but I'm just not sure it's worth the pain to get there. I'm willing to be convinced, though!

I personally don't think we need a "balls-out" class. Yes, there are guys who love the thrill of current B, that includes me and especially Brian. But I really feel few of them would LEAVE combat if performance were dialed back. The thrill of combat is in the cutting, not as much in the speed. IMHO. The turn-off to those who decide to drop out, as well as potential recruits, far outweighs the speed demons, I believe.

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Post by montague »

I don't think it's necessary. I don't think it will at all affect the "drop out rate". And I don't think it will actually slow things down unless you also spec the span, chord, and airfoil. And at that point, you're flying one-design combat.

I've been flying a constant chord wing in SSC all year and doing pretty well with it. My plane is plenty fast, and plenty competitive.

What that shows is that all the "problems" you list with tapered wings can exist with constant chord wings as well. The drag increase is small compared to the other forms of drag on most airframes.


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Post by C/F »

Kirk,
Funny you should drop in because your planes are the prime example of how slow it will become, Your keen eyesight and depth perception is why you are such an ace. IMHO your open B planes are about SSC speed your no taper SSC design whallers around the skies reminicent of designs 2 years old, yet you give everyone fits.

Your arguements fall under the same logic that AJ and Winger could fly anything and still win, yet they showed up this season with 72" wings.......hhmmmmhmm................


Scott,
Respectfully speaking you forgot to mention Q40 flies a longer course than does Q500. Comparing the flight envelope of Q500 racing designs and those needed for combat performance is an apples to oranges comparison. If you design a hershey bar wing for speed you will not enjoy the benfits of stall proof or turning agility, vice versa if you design for the latter your speed will go down. Thus why I feel no limits other than No Tapers be used.
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Post by MLaBoyteaux »

Mike,
I disagree with your assumptions about the effects of constant chord wings on drag versus tapered wings. Here's a great article that describes some of the physics involved with our rc wings.
http://www.rccombat.com/asp/workshop/aerodynamics.htm

Personally, the reason I fly tapered wings is because of the reduced weight a tapered wing offers (this also affects the bending forces of the outer wing panel in an impact), the increased efficiency of the wing at high AOA, and they just look better.

At a high angle of attack, the inboard portion of the wing generates more lift than the outer portion. For a constant chord wing, you've got structure your having to carry which isn't doing it's fair share of the work. By tapering the wing and modifying the wash-out, the wing can be designed to evenly distribute the load and increase efficiency.

The reduced mass along the legth of the tapered wing will also decrease it's roll inertia resulting in a better roll-rate requiring a smaller force.

Watching Kirk Adams at Richmond and Muncie, it's my opinion he's not any slower than anybody else. The few times I saw his planes wallowing around was because they were loaded down with all of our streamers.

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"> For the good of combat in a radical approach to stopping the arms race of design and speed and improving the dropout ratio, I propose that instituting a, "NO" tapers of the wing in Span, width and thickness as the cure all.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Can you give me more detail about how this radical approach is going to improve the dropout ratio?
What I see is a proposal for a "One-Design" format, but I don't understand how it can be a cure all for combat. I think it's a great idea for smoothering new ideas and designs.


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Post by wparmenter »

One design would smother new ideas, but <font color="red">the design would still be competetive five years later</font id="red">. There could still be some innovation in fuse design, but I am sure it would be very subtle just like 424 pylon. Even though the proposal hasn't taken the direction of limited span/chord/thickness, thats what I would like to see.

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Post by montague »

Mike

My B class wings aren't a very good design, but it's not because of the planform, and my B speed is more because of the engines than anything. My B airfoil is too much of a compromise and just doesn't cut it. But even so, it's hardly wallowing or SSC speed. (you will note my B scores reflect that my plane really doesn't perform like I want it to. Hopefully I'll have time to re-design for next year using my 2610 ship as a starting point).

In SSC, I got a really good speed comparison last weekend with a TufFlght Panter. We were flying back and forth, looking at the speed compared to each other. They were almost exactly even. I haven't been able to really compare in a controlled envionment with other designs yet, but I can say that poor engine runs or streamer-mops aside (and those @!#@! loops that always seem to form on my stabs), I really haven't had any problem chasing guys down from behind. A good example of that was the Richmond contest heat where I wound up chaseing Chris Quinn around right on the deck. I'd say the two planes were basically dead even, and I was able to catch up to him by cutting corners on the turns, but I was hardly slower.

I hope to get some really good side-by-side compisons with Lee's Cobra's later this year. Mike, there is a contest in Lenox, MI in Sept. I'm just going to be there one day for the 2610 portion, but if you are going to be there, bring an SSC plane, I'll bring mine, and we can race them around a little for some speed trials. I'm sure you're a little faster, but I might just surprise you.

I will say that Mark really points out some of the places that tapered wings really win out vs straight wings. Anyone who's seen my B ship in a hard turn as noted that the wing visibly flexes. Needless to say, I wasn't expecting that when I built it. There is just too much area creating too much lift too far out on the wing, causing all kinds of problems (and my tip airfoil is much better than the root, making the problem that much worse).


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Post by montague »

From my personal point of view, I spent a fair bit of time creating the airfoil that I use in SSC and 2610, and I am planning to use it in B class, so I'm not terribly thrilled with the idea of not being able to use my work in the future.

Frankly, I think differnet airfoils are better for differnet flying styles, and I want to be able to taylor my plane to fit my style rather than being forced to fly someone else's airplane design that may or may not work for me.

I don't mind restrictions, but I think some design freedom is a good thing. I personally think SSC is better now than it was early on, when the planes were slower, but couldn't manage to launch with a 10mph tail wind. That improvement came from the freedom to mess with the airframe.

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