Hey guys, starting a little home build project and I'm wondering why certain wings do better with slats vs drooped LE, or vice versa. I have a set of scout wings that I am modifying. Extend the flaps a foot and push the aileron out a foot. I'm wondering if drooping the leading edge or putting slats on it would be effective. Any thoughts from the brain trust?

David

So why not both and a set of VG's?? THey all add something and I do not think take anything from the other??

David,

You've opened the bottle and let the genie out, now you've got to give us the grisly details on this "home project". Missing the fun of a small tandem 2-seater? Seems common with you 180 guys.

Karmutzen wrote:David,

You've opened the bottle and let the genie out, now you've got to give us the grisly details on this "home project". Missing the fun of a small tandem 2-seater? Seems common with you 180 guys.

Yup I sure do. I love the 180 for sure, but I just can't get down and dirty with it like I could the citabria.

George, I guess they would all benefit, but at some point the added weight had to start affect things as well. Maybe the LE cuff and VGS are the simplest and best way to go.

The Zenair 701 and 750 homebuilts started out with slats, and they work great, but there has been a lot of movement away from the slats by the builders in recent years.

It has been found on that type of airplane that just building the airfoil out to the same chord dimension as the slatted wing, but "solid" without the slat (covering the hole behind the slat with aluminum), and then adding VG's, works 99% as well.

So you apparently get 99% of the STOL benefits of the slat, but you save time, money and material by not having to build a separate slat.

Now if you droop the leading edge a little, similar to the Sportsman STOL cuff, at the same time as using the VG's behind the cuff... you stand a good chance of making a gain from that.

For the sake of safety and conservative thinking, you probably need to ask an aero engineer whether it will be necessary to increase the size of the tail when you droop the leading edge.

M6RV6 wrote:So why not both and a set of VG's?? THey all add something and I do not think take anything from the other??

Have you guys seen this from Australia's CASA? [url]http://www.flightsafetyaustralia.com/2016/08/whirly-bits-and-why-they-matter/
[/url] From what they're saying some interesting (and undesirable) effects have sometimes cropped up when the airfoil has imperfections, or when lift enhancing mods are piled on helter-skelter. Has anyone on forum heard of, seen, or experienced anything like what CASA describes?

Having grown up flying and learning to fly in a Helio Courier with slats then several thousand hours in a Cessna with various cuffs and VGs, 30 hours in a Highlander and now close to 70 hours in the new Backcountry cub with a slatted wing, I am 150% convinced that there is zero comparison between slats and a cuff with VGs.

Granted, I don't know much about the Zenith aside from the fact that it's a cool little light weight airplane with a nice wing. Id like to see how it does with some slats on that wing

The slats provide a feeling like you just cannot explain until you fly them. I have tried to stall the wing and you cannot. Look what Breeden, Mackey, the boys flying the Superstols, now pops with his slats on the Coyote and others. There is simply not a zenith on the planet that even comes close to that performance. No disrespect to the zenith fliers but that's just a fact. The wings with slats, most anyhow, have VGs. If you have an option between slats or a cuff, IMO there is absoluty no question.

Some may argue the performance comparison here but that's ok. We can agree to disagree.

Go slats! No question

AKT

I'm confused... I thought the Zenith's had slats. I know I've seen some with slats.

Initially I was going to say it depends on your mission, and your wing. You said the basic wing design early on, and have since alluded to your mission... Soo.. I'm going to have to agree with Kevin on this at least 150%. On a cub wing there is no cuff that will even come close to giving you the type of performance gain you will see with a slat or slot for that matter... given it's is what your mission is after.

As to the difficulty comparison between installation... again a no comparison as well as a no-brainerd. Assuming you don't want to re-invent the wheel, that is... Installing a set of Wayne Makey's slats are on the order of magnitude easier than adding a cuff... Still too much work? no sweat... Call Randy Appling of Plaschem and have him build you up a set of carbon fibre slats. They simply glue on over the fabric like a set of VG's. Doesn't get any simpler than that

As a matter of fact... IMHO the slats go on so easy, that now is the time to invest a little extra effort, and add a mixer for droopy ailerons. They will take some of the 'nose pointed to the moon' deck angle out of the AOA necessary to benefit from slats, since they slide the center of lift opposite to the slats... really complimenting each other. And in that same call to Randy, have him throw in a couple sets of spoiler blanks for you. Lengthen the flaps, shorten the ailerons, tie the spoilers to the ailerons, and keep it light... you'll be the next contender at Valdez

Take care, Rob

Rob wrote:Initially I was going to say it depends on your mission, and your wing. You said the basic wing design early on, and have since alluded to your mission... Soo.. I'm going to have to agree with Kevin on this at least 150%. On a cub wing there is no cuff that will even come close to giving you the type of performance gain you will see with a slat or slot for that matter... given it's is what your mission is after.

As to the difficulty comparison between installation... again a no comparison as well as a no-brainerd. Assuming you don't want to re-invent the wheel, that is... Installing a set of Wayne Makey's slats are on the order of magnitude easier than adding a cuff... Still too much work? no sweat... Call Randy Appling of Plaschem and have him build you up a set of carbon fibre slats. They simply glue on over the fabric like a set of VG's. Doesn't get any simpler than that

As a matter of fact... IMHO the slats go on so easy, that now is the time to invest a little extra effort, and add a mixer for droopy ailerons. They will take some of the 'nose pointed to the moon' deck angle out of the AOA necessary to benefit from slats, since they slide the center of lift opposite to the slats... really complimenting each other. And in that same call to Randy, have him throw in a couple sets of spoiler blanks for you. Lengthen the flaps, shorten the ailerons, tie the spoilers to the ailerons, and keep it light... you'll be the next contender at Valdez

Take care, Rob

Thanks Rob. As I mentioned in my first post, it is a ACA scout wing. I want to make it do close to what a cub wing can do. I know I know, many will say just get a cub wing. Problem is, I have these wings here for free. I have lots of ACA parts, and I like the ACA fuselage better. I know I won't be able to do exactly what a cub can do, but I think I can get it pretty close, and have a bit more comfort/speed in between.
I have the fabric off the wings, and am replacing the spars. Also going to lengthen the flaps 1 foot and move the ailerons out 1 foot. I could go 2' with both if I really wanted to. I need to look into the flap hangar brackets and see if I can put Keller flaps on it. I like the sounds of carbon fibre slats. I'll check them out.
Thanks!

Rob wrote:Initially I was going to say it depends on your mission, and your wing. You said the basic wing design early on, and have since alluded to your mission... Soo.. I'm going to have to agree with Kevin on this at least 150%. On a cub wing there is no cuff that will even come close to giving you the type of performance gain you will see with a slat or slot for that matter... given it's is what your mission is after.

As to the difficulty comparison between installation... again a no comparison as well as a no-brainerd. Assuming you don't want to re-invent the wheel, that is... Installing a set of Wayne Makey's slats are on the order of magnitude easier than adding a cuff... Still too much work? no sweat... Call Randy Appling of Plaschem and have him build you up a set of carbon fibre slats. They simply glue on over the fabric like a set of VG's. Doesn't get any simpler than that

As a matter of fact... IMHO the slats go on so easy, that now is the time to invest a little extra effort, and add a mixer for droopy ailerons. They will take some of the 'nose pointed to the moon' deck angle out of the AOA necessary to benefit from slats, since they slide the center of lift opposite to the slats... really complimenting each other. And in that same call to Randy, have him throw in a couple sets of spoiler blanks for you. Lengthen the flaps, shorten the ailerons, tie the spoilers to the ailerons, and keep it light... you'll be the next contender at Valdez

Take care, Rob

Hey I think I need to talk to Randy A!! Can you PM me his info #,
Thanks I already have the droopy stuff in the wing and the cuff, going to need the plastic slats and spoilers!!
I was thinking kind spade type wing tips that deployed along with the spoilers, would need way less rudder that way!!
Got that idea from Pops, or Tom??? Not sure which one!!