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Leading-edge slats

Steve Pierce said:
58 lbs. seems like a lot. How much does a stock wing weigh and how much does a standard Dakota Cub wing weigh?
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My D&E 63" Riblett wings weigh around 30 lbs more than a stock cub wing but they also have 22 gallon tanks. They stall at 25mph indicated at 1500 rpm and 1700lbs. At 1700-1800rpm I can maintain altitude at 28mph. This is without VGs which I hope to fit today and retest. I will also use my gps to see if like Crash the ASI is accurate at the high angle of attack.
I do think deploying the flaps does affect the ASI becuase every notch I add seems to instantly slow the air speed down, faster than the plane could possibly deccelerate, but I guess I will find out.





Sent from my HTC Evo using Tapatalk
 
Back to the original question -
For safety and air speed I would recommend the slats - if you flying is mostly cross country using conventional air strips, probably not worth spending the money
But if you do alot of off field landings/takeoffs it is worth the expense.

Just my thoughts

L
 
Steve Pierce said:
58 lbs. seems like a lot. How much does a stock wing weigh and how much does a standard Dakota Cub wing weigh?
Click to expand...

I've got a stock wing (original piper ribs) with tank, tank cover, aileron and flap in the hanger that I will weigh, if Amy will do the same with a slotted wing with tip etc.

Crash
 
I found my notes that the slots are 8 lbs. heavier than the same extended wing without slots. I have a set of 1983 and 1971 stock wings I will weigh as well. I have weighed the ribs etc. and I know they vary from 6-8 ounces each more than stock. Should be interesting especially since I have been rat holing away stock ribs for years just to stay light on my own project.

Piper Butt Rib 9.7 oz.
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Univair Butt Rib 14.0 oz.
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Piper Tip Rib 5.5 oz.
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Dakota Cub Tip Rib 10.8 oz.
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We weighed a buddy's PA 18 wing last winter after rebuild. Stewarts System. 86 or 88lbs if memory serves me right...no flaps or aileron attached. Empty weight was 1060 on tires when done.

As for the Slats...I want a set for my exp...and will get a set if money allows...Not always about the short TO and landings...rather the safety element afforded by such a mod.

Checked out Lloyds Dakota Coyote in SD, and one point he made stayed with me...he can't spin it...can't get it upside down...
 
J5Ron said:
We weighed a buddy's PA 18 wing last winter after rebuild. Stewarts System. 86 or 88lbs if memory serves me right...no flaps or aileron attached. Empty weight was 1060 on tires when done.

As for the Slats...I want a set for my exp...and will get a set if money allows...Not always about the short TO and landings...rather the safety element afforded by such a mod.

Checked out Lloyds Dakota Coyote in SD, and one point he made stayed with me...he can't spin it...can't get it upside down...
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If you want to do something "safe"....., work on the tail. It's killed WAY more pilots then the wings ever have.


Crash
 
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Crash said:
If you want to do something "safe"....., work on the tail. It's killed WAY more pilots then the wings ever have.


Crash
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What have you done to improve the tail? Other than Charly's tail reinforcement mod what mainstream mods are available to "improve" the tail. Not trying to pick an argument, just interested in what you meant.

SB
 
I moved my finished Carbon Cub wing from the home shop to the hangar to make way for spraying on the left wing. While we were positioning it in the hangar I decided to weigh it since I had a scale there and Rich and Jason to help me. Without the flap and aileron but all other parts included it weighed 66 pounds. This is with CC's 22 gallon tanks too and wingtip light in place. I don't know the weight on the control surfaces yet but will weigh them too. The covering system is Polyfiber with the white being Poly Tone and Aerothane for the trim colors.

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StewartB said:
What have you done to improve the tail? SB
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Make turns with the ball centered.

The FAA had it right some years back when the banned the installation of tundra tires on Cubs. They understood that it was the tail stalling a split second before the upper wing stalled (lower now having all the lift and rolling up and over) that put you on your back in a "Moose Stall".

But in the end...they found out that it WASN'T "disturbed air" coming off of the big tires that caused the tail to stall. It was the big square fuselage sliding sideways through the air in an "un-coordinated" turn that caused it to stall.

Verdict: Operator ERROR. The wings and tires never were the problem.

If you make it "idiot proof", they'll just invent a better idiot.

Crash
 
If you make it "idiot proof", they'll just invent a better idiot.
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Hard to dispute. When guys modify their planes and claim safety they're comparing the mod to stock using stock airspeed and techniques. If the mod expands the performance envelope the pilot will push things to the new limit. Bye bye safety margin. If the pilot doesn't push that limit he probably never needed the mod. There are lots of mods out there that don't appeal to me because I don't need them for what I do. I'm perfectly content with what I have. It doesn't bother me that other guys want slats/slots and some of those guys are really good at utilizing them. But at the same time the pilots I respect and admire most are all flying stock wings. Go figure.

Stewart
 
Crash said:
If you want to do something "safe"....., work on the tail. It's killed WAY more pilots then the wings ever have.


Crash
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If working on the tail means flying coordinated, then ya that's pretty simple.
But explain why you can roll a stock cub on it's back everytime with ease. But when you add VG's, Slotts or Slatts it's virtually impossible. Only a question.

Here's a fact, this entire discussion hinges on ONE THING, you first, have to stall the airplane.
Nothing bad will happen until you STALL. Don't matter what equipment you have or how horse sh$$ a pilot you are, maintain your airspeed and you can fly around all day half cocked if you want.

Brad
 
Now, might be a little off track here, I owned a little Bingo ( like the CH 750 ) and I did try to fly it with out the slats, and I nearly killed myself on the darn thing. I could hang it on the air and nearly touch the tail with it on a slow approach with the slats, and never did get it to stall, until I took them off, and like I said, nearly killed myself. I am on the camp of slats, nice to have and do add a safety margin to a cub, but I can land my cub shorter than I can land a Ch 805 that I have flown... Do I need slats? Not for my flying, would I get slats, if the price was right and STC'd... Maybe.
 
Regarding the tail - I also had Wayne deepen the tail feathers by 5" for more forward visibility in slow flight. Minimal weigh addition. Found out the square feathers did not do the same and original design.
Also the whole idea it to make the plane safer in the slow envelope - not make "idot pilots."

L
 
For the tail I highly suggest elevator gap seals. Even more so than extending the elevator. Cub crafters sells these or you can make the homebuilt versions with a strip of duct tape sealing the top of the gap between the tubes. They keep the clean air flowing over and under the tail which also makes the vg's more effective. During slow flight the gap seals allow you to get a much deeper angle of attack but they also help prevent a moose stall by keeping the tail flying. There is much more control with less stick pressure in slow flight.
I believe that these would be neccessary with slats because they give the tail more authority at the much higher angle of attack acheivable during slow flight.
 
Crash said:
I've got a stock wing (original piper ribs) with tank, tank cover, aileron and flap in the hanger that I will weigh, if Amy will do the same with a slotted wing with tip etc.

Crash
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I'm behind the curve a bit responding here (story of my life) but will find out for you. 8) Currently biding my time waiting for economics class to start, but I have my "what things weigh" cheat sheet at home. The weight will include the 24 gallon tanks.
 
Amy said:
I'm behind the curve a bit responding here (story of my life) but will find out for you. 8) Currently biding my time waiting for economics class to start, but I have my "what things weigh" cheat sheet at home. The weight will include the 24 gallon tanks.
Click to expand...

I'll include a stock tank and lid as well, also don't forget an aileron and flap. Time to get the real weight difference and settle the debate.

Take care,

Crash
 
spinner2 said:
I moved my finished Carbon Cub wing from the home shop to the hangar to make way for spraying on the left wing. While we were positioning it in the hangar I decided to weigh it since I had a scale there and Rich and Jason to help me. Without the flap and aileron but all other parts included it weighed 66 pounds. This is with CC's 22 gallon tanks too and wingtip light in place. I don't know the weight on the control surfaces yet but will weigh them too. The covering system is Polyfiber with the white being Poly Tone and Aerothane for the trim colors.

View attachment 1286
Click to expand...

I weighed my CC control surfaces today. Flap is 4.6 pounds, aileron is 6.2 - both are unpainted weights. Total is 76.8 and the tank cover is unpainted at this point so the final weight would be a little heavier due to the weights for bare aluminum parts.

A few years ago I weighed a stock Piper PA-18 wing after spraying and it came in at 99.5 pounds with the same parts included. The wing was done with Randolph and the flap and aileron with Polyfiber top coated with Poly Tone.
 
spinner2 said:
I weighed my CC control surfaces today. Flap is 4.6 pounds, aileron is 6.2 - both are unpainted weights. Total is 76.8 and the tank cover is unpainted at this point so the final weight would be a little heavier due to the weights for bare aluminum parts.

A few years ago I weighed a stock Piper PA-18 wing after spraying and it came in at 99.5 pounds with the same parts included. The wing was done with Randolph and the flap and aileron with Polyfiber top coated with Poly Tone.
Click to expand...

Trying to get un-covered weights. Covering systems will skew the weights depending on the covering system used. Do you still have an un-covered CC wing you could weigh? Would be interesting to see the difference between the Sport Cub wing and stock Piper.

Weighed a stock PA-18 flap (un-covered) yesterday, 3.6 lbs. One covered weighed 5.2 lbs (heavy / thick dope covering).

Crash
 
Crash said:
Trying to get un-covered weights. Covering systems will skew the weights depending on the covering system used. Do you still have an un-covered CC wing you could weigh? Would be interesting to see the difference between the Sport Cub wing and stock Piper.
Crash
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No. The other wing is already covered now too. CC uses two different types of spars. The Sport Cub has spars with large discs cut out to reduce weight. The Carbon Cub and Carbon Cub kit have solid spars. There are a few other structural differences with the kit too - beefier. Also the factory built planes use light fabric and the kit comes with medium.
 
Sounds like a good plan, I built a exp supercub with Lyc 205 HP in it and have been looking for a set of drawings for some slats. I have been in contact with Wayne and am quite impressed with his slats but cannot at this time afford the $ 4 grand they cost.
 
What would a set of plans for aerodynamically tested and optimised set of slats would go for? ;-) or should I say, willing to pay :wink:

Would people be interested in a retrofit or a wing rebuild? A wing rebuild, meaning you just add new ribs to your wings... considering optimal performance?


Steve, would you give us your PIREP on the before and after of putting in the Slats?
 
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