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B1-B With Swing Wings and Lights

Pieliker96

Well-known member
#1
In the spirit of procrastinating on existing projects by starting and finishing entirely new ones, I present the Bone!


It's around 1.4kg when all is said and done, which is fairly heavy for its wing area (Cube loading is ~7). I'm hoping to hand-launch this, somehow. It's powered by Power Pack C on a 2250 4s, which should give it a TWR of around 1:1. It'll maiden on a 9x6 prop, although I have some 9x9s if I want to try for speed.

Here's some pictures of development:

20191213_102301.jpg 20191213_193356.jpg 20191213_222601.jpg
Lighting control board, burners, and burner testing

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Reasonably skookum spar and wing swing-y bits, using the Actuonix L12-R actuator with a 100mm stroke.

20191218_161018.jpg
Starting to look like something!

20191219_133641_HDR.jpg 20191219_133648.jpg 20191219_145420.jpg
All-moving elevator (not swung) / elevons (swung) setup, using control horns. Note the wheel collars which keep everything in place.

20191219_200210.jpg
All done! Certainly a bit messy in spots. Will require sanding and a coat of paint at some point, but now is not the time.

Maiden flight soon™.
 
Last edited:

SquirrelTail

Well-known member
#2
In the spirit of procrastinating on existing projects by starting and finishing entirely new ones, I present the Bone!


It's around 1.4kg when all is said and done, which is fairly heavy for its wing area (Cube loading is ~7). I'm hoping to hand-launch this, somehow. It's powered by Power Pack C on a 2250 4s, which should give it a TWR of around 1:1. It'll maiden on a 9x6 prop, although I have some 9x9s if I want to try for speed.

Here's some pictures of development:

View attachment 151618 View attachment 151619 View attachment 151620
Lighting control board, burners, and burner testing

View attachment 151621 View attachment 151622
Reasonably skookum spar and wing swing-y bits, using the Actuonix L12-R actuator with a 100mm stroke.

View attachment 151623
Starting to look like something!

View attachment 151624 View attachment 151625 View attachment 151626
All-moving elevator (not swung) / elevons (swung) setup, using control horns. Note the linkage stoppers which keep everything in place.

View attachment 151628
All done! Certainly a bit messy in spots. Will require sanding and a coat of paint at some point, but now is not the time.

Maiden flight soon™.
This thing is gonna be awesome! Now you have to make one the size of your valkyrie!!!!🤣🤣🤣
 

mach1 rc

Well-known member
#3
In the spirit of procrastinating on existing projects by starting and finishing entirely new ones, I present the Bone!


It's around 1.4kg when all is said and done, which is fairly heavy for its wing area (Cube loading is ~7). I'm hoping to hand-launch this, somehow. It's powered by Power Pack C on a 2250 4s, which should give it a TWR of around 1:1. It'll maiden on a 9x6 prop, although I have some 9x9s if I want to try for speed.

Here's some pictures of development:

View attachment 151618 View attachment 151619 View attachment 151620
Lighting control board, burners, and burner testing

View attachment 151621 View attachment 151622
Reasonably skookum spar and wing swing-y bits, using the Actuonix L12-R actuator with a 100mm stroke.

View attachment 151623
Starting to look like something!

View attachment 151624 View attachment 151625 View attachment 151626
All-moving elevator (not swung) / elevons (swung) setup, using control horns. Note the linkage stoppers which keep everything in place.

View attachment 151628
All done! Certainly a bit messy in spots. Will require sanding and a coat of paint at some point, but now is not the time.

Maiden flight soon™.
This is going to be an awesome plane. It will look so cool in the air😎👍👏
 

mayan

Well-known member
#8
In the spirit of procrastinating on existing projects by starting and finishing entirely new ones, I present the Bone!


It's around 1.4kg when all is said and done, which is fairly heavy for its wing area (Cube loading is ~7). I'm hoping to hand-launch this, somehow. It's powered by Power Pack C on a 2250 4s, which should give it a TWR of around 1:1. It'll maiden on a 9x6 prop, although I have some 9x9s if I want to try for speed.

Here's some pictures of development:

View attachment 151618 View attachment 151619 View attachment 151620
Lighting control board, burners, and burner testing

View attachment 151621 View attachment 151622
Reasonably skookum spar and wing swing-y bits, using the Actuonix L12-R actuator with a 100mm stroke.

View attachment 151623
Starting to look like something!

View attachment 151624 View attachment 151625 View attachment 151626
All-moving elevator (not swung) / elevons (swung) setup, using control horns. Note the linkage stoppers which keep everything in place.

View attachment 151628
All done! Certainly a bit messy in spots. Will require sanding and a coat of paint at some point, but now is not the time.

Maiden flight soon™.
This is totally mind blowing well done. I can't wait too see the maiden video.
 

Pieliker96

Well-known member
#10
Having to build many of the forward bay CG fixing fuel tank of the 100%, how are you dealing with the swept CG shift because I can't see this going sonic
The CG will shift back a little when the wings sweep, but the center of pressure / lift will move much more aft. I expect that the all-flying stabs will have enough authority to keep the nose up, although the only way to find out is to fly it.
 

Piotrsko

Well-known member
#11
Actually keep the nose down, but I won't quibble. Any way to stick a weight on the jack screw end so it moves forward with the sweep? OR program a bit of down into the ailerons, like maybe 2.5 degrees mixed into the sweep weighted towards full sweep? Guessing you're not a luddite like me and have a current computer radio that mixes.
 

Pieliker96

Well-known member
#12
It could be possible, but I'm a bit averse to adding more weight as it's pretty heavy as is. The ailerons are on a single channel (I'm limited by 6 channels) - if I could have I would have done flaperons for takeoff and landing.

Correct me if I'm wrong, but the center of lift and center of mass both move back with the wings sweeping aft, with the center of lift moving much more so. This effectively makes the craft nose-heavy, which requires more up-elevator trim.
 

Piotrsko

Well-known member
#13
The center of pressure moves rearward much faster than the CG causing a pivot about the CG because there is an up force related to lift which is more or less centered on the CoP. If the CG is in front of the CoP, it's a nose down couple, much like a high thrust centerline. If the CG is behind the CoP, it's really pitch unstable nose up. That is why the cg is traditionally located near the high point of the wing. Also as the craft goes sonic, the CoP moves much faster rearward still. WW2 aircraft like the P47 and P51 were capable if sonic in a dive, but lacked sufficient downforce in the trim system. The result was breakup from an abrupt nose up moment at sonic transition. Refer also to stories about Glamorous Glennis the Bell X1 and the crash at Reno couple years back.
Doesn't really matter what happens if you have enough trim force to counter it, but, my contemporaries back in the 80's gave up on functional swing wings. There are other strategies: start with a aft limit CG, and deal with the trim penalties open, or fly it in a fixed mode, moving wings other times. Another is a twist or two of permanent down trim on the ailerons making them semi fixed flaperons like a flying wing if they are big enough. Lastly, popout canards have proven to be functional (think F14) and @L Edge current f15 foamy.
 

Pieliker96

Well-known member
#14
WW2 aircraft like the P47 and P51 were capable if sonic in a dive, but lacked sufficient downforce in the trim system. The result was breakup from an abrupt nose up moment at sonic transition.
I assume you're talking about "mach tuck" here. If I've interpreted correctly, the "abrupt nose up moment" is not the plane itself physically pitching up but rather the pilot's control inputs necessary to keep the plane from nosing down (a lot of nose-up, as it were), which caused a ton of structural load. The extent of my education on this subject is a documentary I watched on the P-38 that described the various first encounters with mach tuck and attempted solutions.

Luckily I won't have to deal with transonic flow at this scale :)
 

Pieliker96

Well-known member
#15
Had a successful maiden flight today, video below.


Thoughts:
-Having someone else launch it is a necessity
-I had a ton of control authority in pitch and roll, more than really necessary
-Balance was pretty close to neutral - the battery could be a bit farther forwards
-It had a tendency to "deep stall" (The tailplane loses effectiveness in the aerodynamic shadow of the main wing) which is evident on takeoff
-The burners were somewhat visible in daylight, they'll probably look better at dusk or night

I also managed to split some wood within the swing wing mechanism, which prevented a second test flight and test of the swing wings.
 

L Edge

Well-known member
#16
Had a successful maiden flight today, video below.


Thoughts:
-Having someone else launch it is a necessity
-I had a ton of control authority in pitch and roll, more than really necessary
-Balance was pretty close to neutral - the battery could be a bit farther forwards
-It had a tendency to "deep stall" (The tailplane loses effectiveness in the aerodynamic shadow of the main wing) which is evident on takeoff
-The burners were somewhat visible in daylight, they'll probably look better at dusk or night

I also managed to split some wood within the swing wing mechanism, which prevented a second test flight and test of the swing wings.

Well done!!! Two suggestions I would give you are:

1) Reduce the speed of the servo(s) as it translate back and forth. I set mine for 2 sec. Reason for that is reduces the chance of stripping gears in the servo if there is a bind. That was my problem.
2) First time you make the translation, put the plane in an arc and change the wing when there are very low G forces. It it binds initially, might have a chance to save it.

Is your swing wing movement control by the throttle or just a switch? I used it both in going aft as well as forward motion. It gave me 45 degrees negative and 33 degrees positive. This can be done rather easily with a TX that has a graphic throttle curve.
 

Mr. Gandalf

Well-known member
#17
Had a successful maiden flight today, video below.


Thoughts:
-Having someone else launch it is a necessity
-I had a ton of control authority in pitch and roll, more than really necessary
-Balance was pretty close to neutral - the battery could be a bit farther forwards
-It had a tendency to "deep stall" (The tailplane loses effectiveness in the aerodynamic shadow of the main wing) which is evident on takeoff
-The burners were somewhat visible in daylight, they'll probably look better at dusk or night

I also managed to split some wood within the swing wing mechanism, which prevented a second test flight and test of the swing wings.
This is awesome! Excellent work!(y)
 

Pieliker96

Well-known member
#19
Well done!!! Two suggestions I would give you are:

1) Reduce the speed of the servo(s) as it translate back and forth. I set mine for 2 sec. Reason for that is reduces the chance of stripping gears in the servo if there is a bind. That was my problem.
2) First time you make the translation, put the plane in an arc and change the wing when there are very low G forces. It it binds initially, might have a chance to save it.

Is your swing wing movement control by the throttle or just a switch? I used it both in going aft as well as forward motion. It gave me 45 degrees negative and 33 degrees positive. This can be done rather easily with a TX that has a graphic throttle curve.
It's a linear actuator that takes ~8 seconds to go through full stroke. I've got it on a 3-position switch which will allow me to ease into the wing sweep, which will be done in a stable configuration as you suggested.