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slope soaring

ergomir

Junior Member
Hi, i am new too in slope soaring, and this thread was very useful, i cannot give more advice than the previous ones on this thread, but i will leave you 3 videos i made of my slope experience. I still have a lot to learn, for example, i cannot reach good speed to make hammerheads or graceful loops. Sorry for my broken english ;)


This is my first non-powered sloper:

I hope see your flight videos soon!
 

Wildthing

Well-known member
Hi, i am new too in slope soaring, and this thread was very useful, i cannot give more advice than the previous ones on this thread, but i will leave you 3 videos i made of my slope experience. I still have a lot to learn, for example, i cannot reach good speed to make hammerheads or graceful loops. Sorry for my broken english ;)


This is my first non-powered sloper:

I hope see your flight videos soon!
You got me beat :)
 

Piotrsko

Well-known member
@ergomir: you are not flying fast enough you only go slow on very light days. Use more Down elevator trim so that the plane slowly gains altitude, or maybe 2 circuits to gain enough height to comfortably dive for a loop. Slope flying trades speed for altitude, Or altitude for speed. It is exactly like flying power, only the engine is not running and you are using the lift updraft for power. The motor glider in the first video looked about perfect
 

FoamyDM

Building Fool-Flying Noob
Flights are looking great! From the porpoising it looks like she might be a touch tail heavy - or perhaps the wing incidence needs to be up just a tiny tiny bit - maybe a half a degree up on the leading edge, or maybe just a touch of down elevator trim. The glide slope looks great though, and she looks nice and predictable with a straight forward stall - I think you have a great performing glider there! :D
Is there any reflex in the Alula? I'm building a DTFB version... And my "success" wasn't wild. Is that a wind - required plane?
 
Hi, i am new too in slope soaring, and this thread was very useful, i cannot give more advice than the previous ones on this thread, but i will leave you 3 videos i made of my slope experience. I still have a lot to learn, for example, i cannot reach good speed to make hammerheads or graceful loops. Sorry for my broken english ;)


This is my first non-powered sloper:

I hope see your flight videos soon!
That looks like a great hill, nice videos!
 
Is there any reflex in the Alula? I'm building a DTFB version... And my "success" wasn't wild. Is that a wind - required plane?
(EDIT: I'm wrong about reflex here, see posts further down the page.)

There's no reflex in the Alula, but the trailing edge is much thinner than you'd be able to get with an FT style wing. The airfoil is a pretty complex shape. It thins out from the root then gets a bit thicker and turns up at the wingtips or something like that, it's hard to tell. The Alula doesn't require much wind at all.
 
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FoamyDM

Building Fool-Flying Noob
@Tronglodon , Here are some of the Al-Ula Picture links.

With the Iron method, I can get VERY thin crisp edges, and when I remove one paper surface, Lighten the craft by 25% (19g/in^2 to 14g/in^2) I think the AUW was less than 100g

And the failed Glide test is at the bottom. I will put together a page for this when I have success.
Is there something special, like, "when there is no wind it takes a dive.", that might help get this one to be flying fun.
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As I started a different project (BoT) this may be a moment.
 

Piotrsko

Well-known member
@FoamyDM: If you can fly it again immediately without bending, poking, taping or any otherwise tweak, it was sucessful. The perfect flights kinda leave you weak in the knees for a while and temporarily stop you from flying for a bit. The stall hints it is too aft CG for FT STYLe foamboard wings. Plank style craft should mush or nose bob at stall.

Ps...throw harder
 
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FoamyDM

Building Fool-Flying Noob
@FoamyDM: If you can fly it again immediately without bending, poking, taping or any otherwise tweak, it was sucessful.

Ps...throw harder
@Piotrsko , I did later (off camera). It led to almost immediate nose plant and this:
1560977860317.png
You can see in both of these pictures how thin the FB gets after the iron.
1560978002952.png
I will try to I will get a rubber band launch system for the next testing.
As this model is small (1 sht. it is a good candidate for a quick easy build.)

Any launch tips - like throw 45° to the wind?
 

Piotrsko

Well-known member
Sorry, I never got good at flinging gliders, didn't need to. @bracesport looks to be your hero there. However, do you grab it aroung the CG and point nose high? Or you need some up reflex on the elevons maybe 1/4 inch. Watched the video in close up slowmo, saw what looks like negative reflex on bottom of elevon possibly caused by your iron method.

If you are going to keep trying, power it up and try once with full up trim. Radio doesn't need to be on for that. Should bobble stall. Yours look like down elevon tuck under.. I like to test into a 5-7 mph wind so you can get a feel if it wants to naturally fly. Lightly Hold on GC and it should get a flying feel and want to lift out of your hand if it's rigged right.
 
@Tronglodon , Here are some of the Al-Ula Picture links.

With the Iron method, I can get VERY thin crisp edges, and when I remove one paper surface, Lighten the craft by 25% (19g/in^2 to 14g/in^2) I think the AUW was less than 100g

And the failed Glide test is at the bottom. I will put together a page for this when I have success.
Is there something special, like, "when there is no wind it takes a dive.", that might help get this one to be flying fun.
View attachment 134031
View attachment 134030
View attachment 134032

As I started a different project (BoT) this may be a moment.
I took a few photos of my Alula which made me think of a few things. First, here's the trailing edge. It doesn't get thin right at the edge, but thins out pretty far up in the wing.
IMG_20190619_143514.jpg

Here's a pic of the tail showing just how thin that is. The whole plane is really slim, At the thickest part of the wing it's barely two pieces of foam board think, if that. So my guess is since you put a spar at that point of the wing, it's probably about 50% too thick there.
IMG_20190619_143612.jpg
Last pic is just a wide view of the wing, trying to capture a bit of the complex shape.
IMG_20190619_143654.jpg
I think the reason to has been such a successful but hard to copy design is because of some black magic in the airfoil design. It glides just fine in still air, it can handle a gentle toss or a hard wingtip fling, and it penetrates well in pretty strong wind even without extra ballast. For sidearm launches it prefers being thrown level with the horizon instead of at an upward angle.
 
AHA!! Whole bunches of reflex in those real thing alula pictures including the tips. Thanks @Tronglodon

Btw thick or thin just affects speed and stall AOA.
Oh cool, I was uncertain on what "reflex" means. I read up a bit and yes, there is reflex in the Alula wings, I just didn't know the right word so instead said "black magic." 😸 Sufficiently advanced science, I guess.
 

FoamyDM

Building Fool-Flying Noob
I like to test into a 5-7 mph wind so you can get a feel if it wants to naturally fly. Lightly Hold on CG and it should get a flying feel and want to lift out of your hand if it's rigged right.
When testing there were moderate gusts of wind about that fast and it was definitely pulling up from my fingers. I started with level elevons, then a slight reflex, then big reflex.
I took a few photos of my Alula which made me think of a few things. First, here's the trailing edge. It doesn't get thin right at the edge, but thins out pretty far up in the wing...
[removed for safety]
...I think the reason to has been such a successful but hard to copy design is because of some black magic in the airfoil design. It glides just fine in still air, it can handle a gentle toss or a hard wingtip fling, and it penetrates well in pretty strong wind even without extra ballast. For sidearm launches it prefers being thrown level with the horizon instead of at an upward angle.
Thank you for the information about the launches. My tail is Very thin too. I keep at it until the paper, in essence, meets. taper the length of the iron's soleplate, to half thick then turn over and do the same to the other side.
1561036236684.png 1561036270765.png
Looking into it I did notice, on the orginal Alula, it has a different sections from wing base to tip, this may be where the "magic" comes from.
Then I look HERE, and see traditional KFm9 or Smoothed version should all work.

According to this site, I have two choices here in North Carolina for slope soaring. both at the Beach on the north end... 4hrs away.
Oh, well.

y'all have inspired me, I will work on this again tonight.
 

FoamyDM

Building Fool-Flying Noob
May-hap this is the place to ask.
When working/flying with my FT-Simple Soarer (now in dire need of a rebuild after a reversed Aileron caused a looped, nose first crash.) I seem to have two modes. one is when the motor is on, and the other is when it's gliding. they have different elevator baselines. If it was 0 trim for Gliding/soaring, then I would need up elevator stick to fly powered.
Did I set it up wrong, or is that typical?

How do you set up for different elevon or elevator base trim modes? (climb, glide, thermal) My search skills have missed these vids or blogs detailing it.
 

Piotrsko

Well-known member
Been my experiences that it is a one or two click trim difference between powered and glide mostly depending on thrust line difference from wing centerline. If the motor is on a pod then you might need bunches up elevator. On my bronco, I just remove the prop. On elevon ships, once again, there shouldn't be much difference that couldn't be handled by trim adjustment.
 

ergomir

Junior Member
All this talk about slope soaring just put me anxious for good winds!
I have this plane for a year waiting for the maiden, was a Diamond 1800 (without motor nowdays) but i am afraid the profile is too thick. Someone try it before?


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