4 sheet 80" wing build thread

[evranch]

The wire runners on the floats work perfectly. I put 2 on the outside edges of each float for a total of 4. I can actually taxi it now and on landing it slides for miles. Maybe it slides too well, I had to jump over it on my first landing coming towards me!

I also did the wingtips on my Spear as they were getting chewed up by the ice and snow. In fact, I think I'm going to add this style of runners to all my planes.

I haven't tried taking it off, because I tested the overhead pull launch and for sure this is the way to launch wings. I'll make a thread and a video on a day that it's not snowing, because this method is underrepresented for sure. Almost impossible to mess up and it's actually really fun and satisfying.

My first tests were with the Spear because it's lighter and easier to handle. Because it can pull vertical, it just took off like a rocket for the clouds in a perfectly stable climb.

This wing doesn't have the thrust to pull vertical, but if you're into rockets or KSP it basically does a gravity turn. It pitches down from vertical until it ends up flying level at about 20-30' off the ground with minimal input. Seems pretty reliable, which means it's time to kit this thing out with some FPV equipment

 

[BATTLEAXE]

The wire runners on the floats work perfectly. I put 2 on the outside edges of each float for a total of 4. I can actually taxi it now and on landing it slides for miles. Maybe it slides too well, I had to jump over it on my first landing coming towards me!

I also did the wingtips on my Spear as they were getting chewed up by the ice and snow. In fact, I think I'm going to add this style of runners to all my planes.

I haven't tried taking it off, because I tested the overhead pull launch and for sure this is the way to launch wings. I'll make a thread and a video on a day that it's not snowing, because this method is underrepresented for sure. Almost impossible to mess up and it's actually really fun and satisfying.

My first tests were with the Spear because it's lighter and easier to handle. Because it can pull vertical, it just took off like a rocket for the clouds in a perfectly stable climb.

This wing doesn't have the thrust to pull vertical, but if you're into rockets or KSP it basically does a gravity turn. It pitches down from vertical until it ends up flying level at about 20-30' off the ground with minimal input. Seems pretty reliable, which means it's time to kit this thing out with some FPV equipment

That's awesome man! i am excited for you. Sounds like a good day you had for experimenting and testing. In the spring I should do a drive down to your area or meet up with you somewhere and do a weekend fly. I know i would be game

 

[evranch]

The best thing about this hobby is getting to learn things about airplanes and their design! It's rare to get a day with no wind, mild temps AND nothing important to do around here. I spent the rest of my daylight flying like 30 touch and gos off the ice until I lost one of the flag wire runners to an ice chunk. I'm loving this big plane because it doesn't fly like a model, it flies like a small aircraft. It's fun just to fly circuits.

I was talking on another thread about not needing LRS, but with something this visible in the sky you can easily fly it too far. I failsafed on my park flyer FrSky receiver a couple times before realizing I was flying back and forth across half a mile, and now I'm putting an R9 receiver in it.

Saskatoon is supposed to be hosting a Father's day combat event... might be fun to meet up and crash some foam up!
Also I might be in AB this summer to do my ultralight license if things work out. Looking at the delta wing trikes which might be the reason I'm building these deltas lately?

 

[BATTLEAXE]

I have yet to get into an actual combat. I like flying the combat planes, fun to build as well. Definitely getting into that this summer too

 

[evranch]

Me neither, I'm hoping to actually show up at some events this summer and see how it goes. The guys in Saskatoon do streamer combat so you can fly whatever you want, though there are still plenty of collisions. I like the combat planes as well, they are fun flyers.

 

[BATTLEAXE]

Me neither, I'm hoping to actually show up at some events this summer and see how it goes. The guys in Saskatoon do streamer combat so you can fly whatever you want, though there are still plenty of collisions. I like the combat planes as well, they are fun flyers.

Which ones do you have?

 

[evranch]

Just the Bloody series, though right now I have none! I crashed my Baron one too many times and cannibalized my Wonder for the power pack because I found that I always flew the Baron. The Wonder is a good plane too and tracks nicely, but I found for that sort of flying I really liked having the rudder available.

I decided to swap my entire R9M/Pixhawk setup from my old Maja over to this wing to see how it handles elevon flying. That plane is parked so the system is going to waste. It's cool as I've been able to adjust all the servos to work together perfectly, since the throws were off a bit on the Y-cables. Still doesn't look like I'll get the crow brakes, though.

Once I'm done this project, I should probably build another Baron or two...

 

[BATTLEAXE]

Just the Bloody series, though right now I have none! I crashed my Baron one too many times and cannibalized my Wonder for the power pack because I found that I always flew the Baron. The Wonder is a good plane too and tracks nicely, but I found for that sort of flying I really liked having the rudder available.

I decided to swap my entire R9M/Pixhawk setup from my old Maja over to this wing to see how it handles elevon flying. That plane is parked so the system is going to waste. It's cool as I've been able to adjust all the servos to work together perfectly, since the throws were off a bit on the Y-cables. Still doesn't look like I'll get the crow brakes, though.

Once I'm done this project, I should probably build another Baron or two...

I am all out of combat planes as well. I will build another soon, maybe of my own design, I got some ideas, a mix of all the ones I have flown and then some

 

[evranch]

Yeah, some unconventional combat planes would be cool. I've been wondering how something like the White Diamond would do in streamer combat. Fast to build, super agile, light and cheap components, protected prop in slot and elevons. And you can pull the streamer from the back unlike most pusher/elevon builds. You know as well as me that the smaller the battery the less $CAD the entire build is, and the Diamond runs on an 850mAh 3s.

And I got my split elevons working, turns out that there is an entire mode that they call "differential spoilers" for this purpose: https://ardupilot.org/plane/docs/differential-spoilers.html

Differential braking on the rudder stick, full width braking on the flap lever. The bias can be trimmed, and right now at defaults it's almost definitely going to drop one wing when I try to yaw it. Have to fly it and see. I'm thinking throwing full brake will almost drop it right out of the air with the size of the elevons.

I have an original Pixhawk on there but now that ArduPlane runs on cheap quad boards it seems like a no-brainer to run split elevons if you have the space for them.

 

[BATTLEAXE]

Differential braking on the rudder stick, full width braking on the flap lever. The bias can be trimmed, and right now at defaults it's almost definitely going to drop one wing when I try to yaw it. Have to fly it and see. I'm thinking throwing full brake will almost drop it right out of the air with the size of the elevons.

Couldn't you mix this with the ailerons function, where it acts like differential drag on the inside wing tip of the turn, maybe where it has a bit more travel on the upswing on the outer elevon to drag harder on the inside of the turn... if that makes sense

 

[evranch]

more travel on the upswing on the outer elevon to drag harder

There are parameters to tune which elevon half crows up or down, and how much relative movement they have. I set them to be roughly balanced for my first test flight. The inner elevon moves up more strongly just due to the geometry of the servos, but the outer elevon should have more roll authority because it's further out.

If I take my hand off the rudder stick it will just go back to normal, so I'm going to be gentle with rudder application and see what happens, then tweak it.

 

[BATTLEAXE]

There are parameters to tune which elevon half crows up or down, and how much relative movement they have. I set them to be roughly balanced for my first test flight. The inner elevon moves up more strongly just due to the geometry of the servos, but the outer elevon should have more roll authority because it's further out.

If I take my hand off the rudder stick it will just go back to normal, so I'm going to be gentle with rudder application and see what happens, then tweak it.

You could also hook it up to a 2 position switch to turn it on and off, or do the differential drag mechanically with the servo arm.

 

[evranch]

do the differential drag mechanically with the servo arm

I've been thinking about how you propose doing this and can't figure it out. Unless you are talking about having no rudder channel, and setting up the servos so that aileron input will automatically crow the inner wing?

I think this could work with ailerons but I'm not sure if it would work with elevons, since the elevator input is in there as well. I don't think you're getting away with less than 5 channels on the radio, or 3-4 channels and local mixing on the plane with or without auto-rudder.

Too windy today for test flying and besides, I can't get the compass to behave on the Pixhawk so that it will arm after a firmware upgrade. Even though I don't even need the autopilot functions for this test...

 

[BATTLEAXE]

I've been thinking about how you propose doing this and can't figure it out.

I have done this on a wing or two before, it's just a mechanical advantage based on the rotation of the servo arm. You get more up reflex on the inner aileron then down on the outer

You see here how the servo arms are pointed back at 45 degrees, this gives a more linear motion to the up stroke, and a more rotational motion to the down stroke. Effectively giving you almost twice the up compared to the down. The advantage is that you will get a more coordinated turn when banking without rudder. The disadvantage is that your rolls will be less axial and want to drop in elevation a little once upside down, more of a barrel roll.

 

[evranch]

Oh yeah, I see what you're talking about. The wing is set up like this already to compensate for the lost throw due to the reflex. I was trying to say the same thing when I said

The inner elevon moves up more strongly just due to the geometry of the servos

Also it's hard to talk about inner and outer when the elevons are split! Inner in the turn, or inner towards the fuselage? Heh. The wind is dropping and I've got the battery charging, going to try to fly this thing today.

 

[BATTLEAXE]

Oh yeah, I see what you're talking about. The wing is set up like this already to compensate for the lost throw due to the reflex. I was trying to say the same thing when I said



Also it's hard to talk about inner and outer when the elevons are split! Inner in the turn, or inner towards the fuselage? Heh. The wind is dropping and I've got the battery charging, going to try to fly this thing today.

Yea so we are on the same page on the servos. What if the outer elevons (meaning the wing tip ones) had the differential drag and the inner ones were standard, do you think that would help?

 

[evranch]

That probably would work well, but you'd be either giving up those surfaces for dedicated air brakes, or need 3 servos per wing now! It turns out that just making them split evenly up and down was sufficient to avoid any ill effects.

It was a little windy to really get good results but the rudder stick definitely hauls the nose around aggressively by crowing one wing. It doesn't drop the wing, but it does drop the nose somewhat and quite a bit of airspeed due to the drag at full throw. I guess that's to be expected. It does really cut down turn radius, though.

Pulling the flap lever to drag both wings isn't very effective in the air. It spoils all lift and the nose drops hard. It's easier to slow down just by hauling the nose up and floating in a high-alpha stall. However it's great for braking on the ice after landing, it comes to a stop much quicker. Less chance to be beat up by ice chunks.

The nervous moment of the day was flipping the fly by wire switch on the autopilot after the yaw tests... I never trust computers to fly for me until I have some flight hours on them. I did some tuning flights and it seems that Arduplane is pretty good at flying delta wings, though it prefers to bank rather than yank. I believe there is a setting to add more elevator in turns that I'll have to set up to get tighter turns and less altitude loss.