Hershey bar wings

Build a RV-9

One of the reasons I chose to build a 9 was the longer, wing. I just think it looks a lot nicer than the 7 wing. I know, I'm shallow - what can I say???

DonFromTX said:

An even better choice for having several wings - is the RV12. One could have wings for any purpose, takes only a couple of minutes to change them from the "weekday" wings to the "Sunday" wings.

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Cool idea, But man, that would be a POH, DAR, FAA, and FAR nightmare.

hmmm, wonder if i could think of any more three letter issues?

Good looks and performance?

Careful you don't set the bar too high.



"If you want to be happy for the rest of your life,
Never make a pretty woman your wife."

Kid Creole and the Coconuts.

I have flown Our RV-6A with 6 different wing configurations

I have flown out RV-6A with the following wingspans:

1) 24.5' - Original configuration with two 9" tip tanks added - normal travel
2) 23' - Two 3" streamlined tips inplace of stock (no lights)
3) 21.5' - Tip tanks removed and 3" streamlined tips
4) 21.25' - Asemetric with one flat metal tip and one 3" streamlined tip
5) 21.25' - Two 3/4" semi-flat fiberglass tips
6) 21' - Two flat metal tips

Configuration #1 is what I use for travel with the greatest range and with lights for night flight. Configuration #2 is for long distances races to keep the range but reduce the drag. Configuration #3 it the fastest and is used for most racing but with 17 gallons less fuel. Configuration #4 was just to test the difference in yaw with different tip designs. Configurations #5 and #6 were experiments to get more speed without success. I could easily make round or eliptical or any other shaped tip if I were only interested in some special shape. 1, 2 and 3 are what work for me.



Bob Axsom

Tanks

Bob: Can you say more about the tip tanks? Capacity, gravity or pumped? Flow to main tanks?

Which one?

Bob, which configuration is in the photo?

looks like #3

My Tip Tanks

Some of your questions are answered by my post above yours.

My tip tanks were manufactured and offered to the RV community by a fellow named Farn Reed in Grants Pass, OR. they require a little support structure at the end of the stock wing with 3 steel rods in addition to the skin screws (approximately 50 per tank) and they have a built in wire conduit. They were installed by others and everyone designed their own system. All four of my tanks are individually selectable gravity fed. My master fuel valve has a Left Main, Tips, Right Main and off position. The other valve has only two positions Left Tip and Right Tip. The tip tanks increase the capacity to 55 gallons. Here is a photo with the tip tanks and stock lighted tips installed:



Bob Axsom

It is configuration 3

RV7AV8R said:

Bob, which configuration is in the photo?

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You can se the race #71 of course (cut from thin white removable contact paper shelf liner bought at Walmart) but a little more subtle are the subfairings on the landing gear and the NACA vent covers.

Bob Axsom

Gives it a "fast" look. nice plane

Data

RPorter said:

Gives it a "fast" look. nice plane

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Looks are not deceiving in this case:

Race Record (RR)# Race Date Class Aircraft Type Pilot Speed Kts Speed MPH
217 AirVenture Cup 2008 7/27/08 RV Blue RV-6A Axsom, Bob & Jeanine 194.56 223.89
782 Rocket 100, 2010 11/20/10 RV Blue RV-6A Axsom, Bob 192.80 221.87
133 Texoma 100, 2008 4/20/08 RV Blue RV-6A Axsom, Bob & Jeanine 188.36 216.80
753 Tennessee Valley Air Race 2010 10/30/10 RV Blue RV-6A Axsom, Bob 187.52 215.83
233 AirCap 200 8/24/08 RV Blue RV-6A Axsom, Bob 185.16 213.08
298 Rocket 100 2008 11/23/08 RV Blue RV-6A Axsom, Bob & Jeanine 183.83 211.55
809 Taylor 150, 2011 4/2/11 RV Blue RV-6A Axsom, Bob & Jeanine 183.41 211.07
313 Taylor 100 2009 3/16/09 RV Blue RV-6A Axsom, Bob & Jeanine 182.35 209.85
152 BCAF 150, 2008 5/4/08 RV Blue RV-6A Axsom, Bob & Jeanine 181.45 208.81
720 Grace Flight 2010 10/2/10 RV Blue RV-6A Axsom, Bob 181.23 208.54
276 Memphis 100 2008 10/19/08 RV Blue RV-6A Axsom, Bob & Jeanine 180.26 207.44
66 AirVenture Cup 2007 7/23/07 RV Blue RV-6A Axsom, Bob & Jeanine 179.99 207.13
641 AirVenture Cup 2010 7/26/10 RV Blue RV-6A Axsom, Bob 179.83 206.94
363 Tennessee Valley Air Race 2009 6/14/09 RV Blue RV-6A Axsom, Bob & Jeanine 178.98 205.97
179 Colorado 150, 2008 6/29/08 RV Blue RV-6A Axsom, Bob & Jeanine 178.63 205.56
539 West Texas 100 6/6/10 RV Blue RV-6A Axsom, Bob 178.04 204.89
102 Memphis 100, 2007 10/28/07 RV Blue RV-6A Axsom, Bob & Jeanine 176.86 203.52
119 Rocket 100, 2007 11/18/07 RV Blue RV-6A Axsom, Bob & Jeanine 176.33 202.92
25 Wichita 300 7/17/07 RV Blue RV-6A Axsom, Bob & Jeanine 169.91 195.53
17 Taylor 100 2007 5/20/07 RV Blue RV-6A Axsom, Bob & Jeanine 168.72 194.16

Bob Axsom

Mustang II wings on an 8?

Yeah, I know,,, another old post being resurrected. Shows how much time I spend browsing around the forum! Anyway, reading all this got me to thinking (always smell smoke for some reason). The OP likes a tapered wing, which I see the Mustang II has. Anyone ever put those wings on an RV? Seems to me the RV8 would look more like a Mustang, than the Mustang II does. Weird.

An RV-8 with RV-14 wings would be interesting.

More gas (50 gallons), slotted flaps and the higher efficiency of the RV-10 wing design. Add to that it still makes for an aerobatic airplane.

Carl

REALLY!

All this talk slamming Hershey Bar Wings ( I like mine with almonds). What about the SPAM CAN fuselage.

Hershey bar

At the risk of being called a traitor I will comment on the Hershey bar. I own an rv8 and a mustang ll as well. I told a friend of mine who is also an RV driver, that I wish my rv8 had the laminar flow wing like the mustang ll. I also think the appearance of the Hershey bar is a bit unsightly. That is however not why I would like to swap wings. The mustang ll is faster by some 10 to 12 nauts. The mustang ll will fly every bit as solid at slow speeds as my rv8. Say 60 to 70 mph range. I have mentioned on this site before that I can't 3 point my rv8, the mustang 3 point landing is a non event, just set on final at 75 mph and it settles very nicely in a 3 point landing. After having said all that, I am building a 200 hp o-360 for the rv8 and the mustang will soon be on the market. I could go on for a good while about the things I like about the rv8, the wing is just not one of the things. It is still ok to like what you want and dislike what you don't . Regards, Cc

Ha!

I do think you would be staring at the wings in flight like a deer stuck in headlights. Fly the thing and let the wings do their job. Maybe a Grumman Lynx will do.

Carl Froehlich said:

An RV-8 with RV-14 wings would be interesting.

More gas (50 gallons), slotted flaps and the higher efficiency of the RV-10 wing design. Add to that it still makes for an aerobatic airplane.

Carl

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I asked an engineer at Van's about adding the -9's fowler flap to the back of the -8 wing. His response was that the flap would blanket the HS. causing the plane to pitch down and that is the reason the -9, 10, and 14 all have the rectangular HS.

constant-chord wings rock

Ho-kay, everybody who's actually built a pair of tapered wings raise your hands (maybe ten guys).

Now, everbody who's actually built constant-chord wings raise your hands (hundreds of hands go up, including mine

Now, imagine tapered wings:

Imagine those tapered spar webs: The fore and aft depth of each wing rib has to match perfectly (and differently) with the loft of the spar depth at each point along both spars. Same with the leading edge ribs.

Imagine those tapered leading edges - the radius changes along the span - wide at the root and narrow at the tip. Same with the trailing edge radius

The aileron gap fairing has to taper
The flap brace has to taper
The aileron and flap spar webs have to taper

Now make 50 control surface stiffeners, all different sizes, for your ailerons and flaps! And make different end-rib sizes while you're at it.

That simple water pipe counter-balance in the aileron leading edge? - that has to taper as well

You want to assemble a tapered wing and aileron and flap on a flat bench top same as constant-chord? Fuggetaboutit! How're you gonna get that perfect 1-2degree washout (twist) into all those surfaces without jigs?

Your gas tanks have to taper too, as well as have the correct washout over half the span.

But oh, those tapered wings sure look purty! Sooooo purty ... they are worth
4x more work and cost than constant-chord wings

... that is, until you get them into the air, when you realize it doesn't matter a hoot whether your wings are tapered or rectangular or elliptical or shaped like a flying saucer - what matters is their simplicity, reliability, ease of fabrication, and performance.

Van's wings are simple, reliable, easy to build, and fly fabulously!

So build a couple, prove me wrong!

- Steven
(1000+ RV3 hours - another one yesterday!)

Try that pitch over on the Bushby Mustang I & II forums & see how seriously they take you. (Hint: all the early kits were scratch-built.)

N941WR said:

I asked an engineer at Van's about adding the -9's fowler flap to the back of the -8 wing. His response was that the flap would blanket the HS. causing the plane to pitch down and that is the reason the -9, 10, and 14 all have the rectangular HS.

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Actually it is more about the large pitching moment that the big effective flaps produce.

Wings inflight produce a nose down pitching moment that is counteracted by the horizontal stab. Deploying flaps increases this. ( that is why you have to pull back on the stick when you deploy flaps). Big effective flaps require even more nose up counter force...... The reason for the larger stab and elevators on the 9, 10, and 14

highflight42x said:

So build a couple, prove me wrong!

- Steven
(1000+ RV3 hours - another one yesterday!)

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I built every part of the tapered wings on my Mustang II. Really wasn't hard at all, time consuming yes.

Just a pointer back to this earlier thread on tapered wings.

Thanks, Bob K