FTFC23: Build-ruary by Inq: Inq'd Boomerang

[Inq]

Boomerang Progress...

Mostly designing/CAD work today, with some printing.
Here, the design for the wingtip elevons/rudders.

Here, the elevons, and control horns and rudders printed. This portion is 18.7 grams.

 

[Foamforce]

I have broken down and dug out something that I've had for a long time, but has never been on an airplane. Just hope it can be configured for elevons. Haven't dug up the manual yet.
View attachment 234863

It does support elevons! Setup is a little tedious at first due to all feedback coming from a single blinking LED and all input being a single button. I had this working on my first FT Delta. Stabilization worked on that one, but I never got training mode (auto-level) working correctly with it. I moved it over to a Cub and it works like a champ. I chalk that up to my FT Delta being very unstable and never correctly trimmed.

If this plane is supposed to be very lightweight, one thing I found is that the A3 Pro (not V2) doesn’t have throttle pass through. That means that you can’t use the PPM input with it, so you have to run individual wires for each of your channels from your receiver to your gyro. V2 does have throttle pass through so you can run a single wire and use PPM.

 

[Inq]

It does support elevons! Setup is a little tedious at first due to all feedback coming from a single blinking LED and all input being a single button. I had this working on my first FT Delta. Stabilization worked on that one, but I never got training mode (auto-level) working correctly with it. I moved it over to a Cub and it works like a champ. I chalk that up to my FT Delta being very unstable and never correctly trimmed.

If this plane is supposed to be very lightweight, one thing I found is that the A3 Pro (not V2) doesn’t have throttle pass through. That means that you can’t use the PPM input with it, so you have to run individual wires for each of your channels from your receiver to your gyro. V2 does have throttle pass through so you can run a single wire and use PPM.

That doesn't sound very plug-n-play! Sounds like I better set aside some time.

 

[Inq]

Boomerang Progress...
The Boomerang project got the majority of the time-slice today while the F-8 has time to think about itself. Finished the CAD on the elevon parts...

Printed all the parts and assembled the left wing. Right wing isn't even cut out yet in case I need a total redesign on it. So far this is working out OK.

 

[Inq]

Yes, we have a white Labrador! It's not possible to vacuum the fur in my office. I've decided to consider it as insulation!

Question... in case anyone is even looking at this thread and can help. Notice the rudder above. For a flying wing with the rudders way out on the tip like this... it's best to have them work only one way. I learned this studying my plans for Burt Rutan's Long Eze. They only move outward. This is very easy to accomplish with one servo by just using a string. When I want to yaw to the left, only the left string is pulled and moves the rudder above outward... causing more drag on the left side (pulling the wing backward) and to a far lesser degree the force to the right. The right rudder will still be pointed strait back not creating any drag.

The question is... do you think I need a spring to return the rudder to strait back? The string isn't going to push it back. My current assumption is... without the tension on the string to pull the rudder out, the airflow will push it strait.

 

[L Edge]

Yes, we have a white Labrador! It's not possible to vacuum the fur in my office. I've decided to consider it as insulation!

Question... in case anyone is even looking at this thread and can help. Notice the rudder above. For a flying wing with the rudders way out on the tip like this... it's best to have them work only one way. I learned this studying my plans for Burt Rutan's Long Eze. They only move outward. This is very easy to accomplish with one servo by just using a string. When I want to yaw to the left, only the left string is pulled and moves the rudder above outward... causing more drag on the left side (pulling the wing backward) and to a far lesser degree the force to the right. The right rudder will still be pointed strait back not creating any drag.

The question is... do you think I need a spring to return the rudder to strait back? The string isn't going to push it back. My current assumption is... without the tension on the string to pull the rudder out, the airflow will push it strait.

I'm watching, rather than call them elevons I call them movable canards acting as elevons . You are using a one directional rudder, it is interesting. I used the avian approach and end plates( a fixed rudder?) and the only difference is rather than being a aft swept wing, I explored the forward swept wing at 45 degrees !!!

I had some success, but in the process I destroyed 2 ducted fans and 1 battery.

So watching for the results of your video.
I am now exploring a straight wing(no rudder or stabs) but using a totally new concept of handling the roll/yaw problem.

Canards are on thread #23.
https://forum.flitetest.com/index.php?threads/forward-swept-wing-no-fuse-will-it-fly.66599/page-2

 

[Inq]

Canards are on thread #23.
https://forum.flitetest.com/index.php?threads/forward-swept-wing-no-fuse-will-it-fly.66599/page-2

I'm going to have to study your concept... I would have thought it would be very unstable in yaw. Have to see how you overcame that.

 

[danskis]

Yes you need a spring. It will return the control to a consistent position. The downside is you might need a fairly beefy servo. This is the first video I came to and he does a great explanation but I'm sure there are other shorter videos out there. The pull string discussion is at 5:30

RC Glider Basics | Pull-String Tail Linkage - Bing video

 

[Inq]

Yes you need a spring. It will return the control to a consistent position. The downside is you might need a fairly beefy servo. This is the first video I came to and he does a great explanation but I'm sure there are other shorter videos out there. The pull string discussion is at 5:30

RC Glider Basics | Pull-String Tail Linkage - Bing video

I watched it... but it sounds like he's using it to deflect into the airstream for rudder/elevator control on one of the directions. So he'd have to have a spring strong enough to overcome the worst case scenario of control forces. In my case, I'm simply returning it to the neutral position... which (I would think...) the airstream would tend to try to center it. But, I think it sounds prudent to put a light spring to be sure. Thanks.

 

[Inq]

(Lack of) Progress Today...

Two planes are done FT MM DR-1 and F8 Crusader. Most work was done on number 3 being the Fokker D.VIII. It will get done early tomorrow and I'll hop on this one. Doubt it'll make it, but have to give it the olde college try. I did get the second wing cut out, de-papered, and the double bevel cut.

TODO

1. Routering on wing and fold it
2. The plastic pieces for the elevon are already made, just need to put them on.
3. Figure out a strong/light mounting method for the two wing halves.
4. Design/Print the motor mount, and aft fairing for the pusher motor
5. Design/Print the nose piece with ability to move the battery around for CG.

Miracles could happen... depends on if Midnight is UTC or my local time.

 

[Inq]

Put a fork in ME!
I'm not going to finish.

1. got the second wing built
2. elevon attached and working.
3. the detachable cross spar connection... I think will be strong enough. Certainly won't be pulling any high-G acrobatics.

Got to where I need to create a fairing to hold the motor, ESC, battery and 3 servos. I can't see getting it designed, printed and attached in the given time. And that's being optimistic that I get it right the first time. I'll be stopping at three completed planes.

 

[FoamyDM]

Looks great how'd she fly?