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Air Brakes... On a Wing?

#1
I've been touch and go in the hobby for a while (it's a pun, get it?!) due to work soaking up most of my time. But I got a 4 day stretch off and wanted to fly. Have a lot of fixing to do on my Storch and Edge, and my radian is still waiting on parts. So I thought it would be a good time to build a new wing, because why not?
Bought a stack of dollar tree foam board and got to work cutting out plans for a Versa, built it up, recycled some electronics and got it in the air today. Love the plane, absolutely rips and its amazing how fast flying comes back to you after a month or two off.
My only problem, which is probably a flaw in my piloting skills, it lands hot. Like afraid to break a prop fast. SO my mind got to turnin' and wondered, what if i put air brakes on it?
Before I go through the process of designing some in Fusion360 and printing them, has anyone put air brakes on a wing? Im guessing since you dont have the fulcrum of a tail, the placement has to be dead on the center of rotation. All input is greatly appreciated, also if i end up designing printable airbrakes I will gladly share the file!

Happy Flying
 

Hai-Lee

Old and Bold RC PILOT
#3
Firstly airbrakes on a wing will not slow down its approach and landing speeds as these are set by the wing profile and the weight it supports.
Additionally if you fit airbrakes on the wing itself it will immediately lose lift because of the airbrakes breaking the airflow over the wing in the vicinity of the airbrakes. So suddenly the plane will need to approach a lot faster if airbrakes are used on the wing itself.

When properly setup the wing should be able to land with full UP elevator and thereby provide the slowest possible landing speed for the wing loading Etc. I can describe the proper setup if required though I have done so on many other wing related threads,

Should you want airbrakes for either maneuvering or approach purposes they can be implemented but on the vertical fins by using a split fin arrangement which when operated actually causes the fin to open at the trailing edge and spread both to the left and the right at the same time. This will add significant drag and will cause the wing to slow dramatically.

The same arrangement can also be used as yaw control if one side, or the other, is operated under rudder channel control.

I hope that clarifies matters for you!

Have fun!
 

BATTLEAXE

Well-known member
#6
@Hai-Lee is right. I installed flaps on a wing and never got to try them, crashed on the maiden before I got the chance. But his full back elevator trick works on all sorts of wings. Even at cruising speed, cut the throttle and ease back the elevator to full to create a stall, the nose may pitch up, but the wing will slowly drop like it is on an escalator at level pitch. when you get a few feet to the ground, ease up on the stick and it will glide in slow. No need for air brakes or flaps. His vertical split fins idea is cool but a little more involved to build.

I like your idea though it would be cool to see. Take your wing out the next chance you get and try this from like 50' up and you will see what I mean, It is pretty cool to watch and you will be amazed at the drop rate. Your wing is already equipped with brakes and you don't even know it lol
 

quorneng

Well-known member
#7
Hai-Lee
Surely air brakes on landing are not there to reduce the approach speed on any plane but to allow a steeper approach to be made without the planes speed rapidly increasing. A steeper approach makes it easier to position the actual touch down point.
 

Hai-Lee

Old and Bold RC PILOT
#8
You a
Hai-Lee
Surely air brakes on landing are not there to reduce the approach speed on any plane but to allow a steeper approach to be made without the planes speed rapidly increasing. A steeper approach makes it easier to position the actual touch down point.
You are correct but some persons think that simply slowing a wing will make it land slower. Unfortunately wing mounted airbrakes will induce a massive loss of lift and a quicker descent due to the loss of lift.

To slow the landing speed of a wing the only real devices that can be fitted to a wing are LE slats or LE extensions. The slats allow for a slight increase in wing area and better airflow control, (higher AoA), and the LE extensions actually increase the wing cord and hence wing area.

If implementing slats or LE extensions do so in gradual steps so that you do not suddenly find a major upset in trim or even experience loss of control. Ideally the installations should not cause a wing pitch change when they are extended. The only difference will be a possible higher AoA at stall and/or a slower landing speed.

No devices that upset the generation of lift or effect the wings TE airflow are advised.

have fun!
 
#12
Wow! Didn’t expect that many responses that fast. Thank you everyone for your input!
I understand essentially stalling the wing for decent rate, recovering and then doing a final flare out to land. Getting better at it. But It’s been about a year since I’ve flown a wing regularly.
It was more just of a design challenge and an over thinking of solving something. But in the excitement of thinking how cool
It would be I forgot basic rules of aerodynamics.
The split alierons would be really really cool. I’m going to think on how it could best be done, more for a why not factor rather than practicality.
 

Ketchup

4s mini mustang
#13
I think that ft did a video about rudders on wings. Their final version had differential air brakes for rudder, but if you used both at the same time you could slow down a lot. What they did is basically what some people here are talking about. I would suggest practicing the method of stalling the wing, but air brakes on a wing would be a cool experiment to try.
Good luck!
 

Vimana89

Well-known member
#14
A lot of my planes set up easily for a natural "flop landing". A steep angle of attack is good for such an approach if your plane allows. If you can, tweak yours to land right just with elevator as @BATTLEAXE said, I find "just using a pencil" preferable to developing a "million dollar pen that writes in space" if possible as far as solutions go. If you need to add extra jank to your plane to slow your landing, flaps are what you'd want, and what I generally see people using.
 

Vimana89

Well-known member
#15
I like the wingtip rudders idea myself(if anything besides just using up elevator). I don't have any real experience with flying wings, but a lot of good designs I see already have the vertical stabilizers on the wingtips(as I've been thinking for a trainer delta plane). Using these as live rudders will already give you some nice 4ch authority, and the idea to use them as a brake makes perfect sense to me.
 

BATTLEAXE

Well-known member
#16
I don't have a lot of good experience with wings and I just built a Goblin at 130% and I was skeptical of the build to begin with, just cuz it ended up being so heavy compared to anything I have built before just to balance it. I flew it and did a stall test and I will show you what happened here, I was so surprized, check it out at 6:28 and about 7:20

Now I actually added a third set of rates since this maiden where what used to be the high rates is now mid rates, and the now high rates are the same as the mids but I have maxed out the elevator at 125% just for short soft landing. If you don't have the space or an endless supply of props this would save you. I took it out today and the high rates trick worked amazing, no broken prop. And if you land in a head wind it will hover all the way to your feet. It reall isn't that hard to do, both sticks full back all the way to the ground, a little flare at the end. Good Luck (y)
 

Vimana89

Well-known member
#17
I don't have a lot of good experience with wings and I just built a Goblin at 130% and I was skeptical of the build to begin with, just cuz it ended up being so heavy compared to anything I have built before just to balance it. I flew it and did a stall test and I will show you what happened here, I was so surprized, check it out at 6:28 and about 7:20

Now I actually added a third set of rates since this maiden where what used to be the high rates is now mid rates, and the now high rates are the same as the mids but I have maxed out the elevator at 125% just for short soft landing. If you don't have the space or an endless supply of props this would save you. I took it out today and the high rates trick worked amazing, no broken prop. And if you land in a head wind it will hover all the way to your feet. It reall isn't that hard to do, both sticks full back all the way to the ground, a little flare at the end. Good Luck (y)
That looks nice. I think scaling it up did well for the speed envelope and stability!