Michael9865
Elite member
Looking good
Rogue One Zeta Class Transport Shuttle Build Log
- Thread starter SpaceWalker1992
- Start date
SpaceWalker1992
Member
Today, I'm going to be extending the fuselage by about 7 inches to bring it to scale. as you could see in the previous pictures, that wasn't the way it was, and that is one of the reasons the wing pulled the fuselage apart from itself. I'll patch that up and then add on the aft portion of the fuselage.
Cant wait to see this thing bro! If you need a camera man on maiden let me know and i will cruise down.
varg
Build cheap, crash cheap
Cool. It's one of the few star wars ships that looks like it might possibly be flyable without the addition of stabilizing surfaces or significant enough proportion changes to ruin the look. Tandem wing aircraft pose some unique challenges, especially non-staggered wings.
I don't know if that amount of anhedral will be sufficient to make up for the lack of a vertical stabilizer, but if you stand the wings off from the fuselage a bit, like you can see in this model, you might be able to use the nearly vertical portion of the wings just below the wing "roots" to your advantage there.
I don't know if that amount of anhedral will be sufficient to make up for the lack of a vertical stabilizer, but if you stand the wings off from the fuselage a bit, like you can see in this model, you might be able to use the nearly vertical portion of the wings just below the wing "roots" to your advantage there.
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SpaceWalker1992
Member
Thanks for that reference pic and suggestion. I'll take that into account when I re-build the fuselage, make the outer edges shorter so that the wings would get some airflow at the root. I've pulled this quote from an RCG discussion Here that is relevant, and I'll modify the wings to accommodate, or adust trim.
"A tandem wing is just a regular design that happens to have a very big stabilizer. Being so large means that it can be loaded up to provide some of the lift. But the forward wing must still do more of the work than the rear in order to fly in a stable manner. This means that there must still be an angular difference between the forward wing and the "tail" or rear wing. Also the forward wing will benefit from using an airfoil with a little more camber than the rear.
In this case since it is already built he can add in some angular difference and change the wing section camber by slightly drooping the elevator surfaces on the forward wing and reflexing the ailerons on the rear wing. Drooping the elevators down will add camber and some positive incidence to the front wing. Reflexing the ailerons up on the rear wing will slightly reduce the camber and add a slight negative angle to the rear wing." - BMatthews
So I'd apple the opposite, because my aircraft is "tucking upwards" in the test throws.
as far as control for it goes, I can't find a relevant source for the life of me, so I've thought of two methods. first, treat the aft wing as a large inverted V-tail, and the front wing as a regular wing. Second, Make them work in conjunction to rotate each one around the CG (Up elevator would produce ailervatorudder down in front, up in back.) There's nothing stopping me from trying both, since it's just a simple radio mix, though.
On the subject of control surfaces, Do you guys have any suggestions as to how big the surfaces should be? I think around 3 inches by 10 would be good.
"A tandem wing is just a regular design that happens to have a very big stabilizer. Being so large means that it can be loaded up to provide some of the lift. But the forward wing must still do more of the work than the rear in order to fly in a stable manner. This means that there must still be an angular difference between the forward wing and the "tail" or rear wing. Also the forward wing will benefit from using an airfoil with a little more camber than the rear.
In this case since it is already built he can add in some angular difference and change the wing section camber by slightly drooping the elevator surfaces on the forward wing and reflexing the ailerons on the rear wing. Drooping the elevators down will add camber and some positive incidence to the front wing. Reflexing the ailerons up on the rear wing will slightly reduce the camber and add a slight negative angle to the rear wing." - BMatthews
So I'd apple the opposite, because my aircraft is "tucking upwards" in the test throws.
as far as control for it goes, I can't find a relevant source for the life of me, so I've thought of two methods. first, treat the aft wing as a large inverted V-tail, and the front wing as a regular wing. Second, Make them work in conjunction to rotate each one around the CG (Up elevator would produce ailervatorudder down in front, up in back.) There's nothing stopping me from trying both, since it's just a simple radio mix, though.
On the subject of control surfaces, Do you guys have any suggestions as to how big the surfaces should be? I think around 3 inches by 10 would be good.
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ftwingnut
WWI Flying Ace
This model is going to LOOK great when it's done, but aerodynamically, it might be a problem. A few things I am noticing on this:
The anhedral is going to cause an issue if you try to fly it that way, for a couple reasons.
First, anhedral will be severely unstable in the roll axis, because once the craft starts to roll, the higher wing will now suddenly have more lift than the lower wing, accelerating the rolling motion. This is why planes have dihedral, to counteract unexpected rolling.
Second, the anhedral causes the CG to be even higher in relation to the center of lift, which will cause the same unstable effect in roll, but now also in pitch. As soon as the nose starts to rise, the CG will shift rearward in relation to the center of lift, causing the pitching motion to increase.
That being said, I would still make the wings be able to rotate, because, well, that's cool! But I would only have them in the down position for static display. Flight configuration should be in a slightly dihedral position to get the center of lift even with, if not slightly higher than the CG.
As for control surfaces, I would not mix it with pitch control on both the front and rear wings. It will probably be too pitchy and hard to control. I would choose a canard configuration where pitch control is on the front wing and roll control is on the rear wing. That way both front and rear wings can be lifting surfaces. If you tried to use conventional controls where pitch is controlled in the rear, then the rear wing would need to be set at a negative incidence, and would not provide much lift at all, in order to make the plane stable.
Just my 2¢, but hopefully food for thought that will help reduce the hours of frustration trying to make this bird fly. I can't wait to see how you do!
PS, are you going to use any kind of flight controller to help with stability?
The anhedral is going to cause an issue if you try to fly it that way, for a couple reasons.
First, anhedral will be severely unstable in the roll axis, because once the craft starts to roll, the higher wing will now suddenly have more lift than the lower wing, accelerating the rolling motion. This is why planes have dihedral, to counteract unexpected rolling.
Second, the anhedral causes the CG to be even higher in relation to the center of lift, which will cause the same unstable effect in roll, but now also in pitch. As soon as the nose starts to rise, the CG will shift rearward in relation to the center of lift, causing the pitching motion to increase.
That being said, I would still make the wings be able to rotate, because, well, that's cool! But I would only have them in the down position for static display. Flight configuration should be in a slightly dihedral position to get the center of lift even with, if not slightly higher than the CG.
As for control surfaces, I would not mix it with pitch control on both the front and rear wings. It will probably be too pitchy and hard to control. I would choose a canard configuration where pitch control is on the front wing and roll control is on the rear wing. That way both front and rear wings can be lifting surfaces. If you tried to use conventional controls where pitch is controlled in the rear, then the rear wing would need to be set at a negative incidence, and would not provide much lift at all, in order to make the plane stable.
Just my 2¢, but hopefully food for thought that will help reduce the hours of frustration trying to make this bird fly. I can't wait to see how you do!
PS, are you going to use any kind of flight controller to help with stability?
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SpaceWalker1992
Member
those are some great points. I've test thrown it, and it hasn't had any issues rolling from what I can tell. I do think that having at the very least a flat wing would be likely more of a realistic goal to shoot for. I also didn't think about the front wing as a canard, that's a great idea. I'll try that first. I'll record a few test glides and compare, then upload so you guys can speculate. I don't want to have to use a flight controller, but if It has some silly tendencies that can be remedied with one, then I think it would be worth it to.
EDIT: test flew it, it is acting a little as you described at times. 3/5 throws had it nosing up and stalling, then falling down backwards. I think I'll turn the wings flat for now.
EDIT: test flew it, it is acting a little as you described at times. 3/5 throws had it nosing up and stalling, then falling down backwards. I think I'll turn the wings flat for now.
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Hey guys,
LOVING this build log as well as the comments.
@spacewalker92 - THIS thing looks sweet and I REALLY hope it flies... WE all here at the shop are hoping it SUCCEEDS! ha
@localfiend - That At-At... IS SICK! and I can't wait to see the finished product! You will have to send us one to display at the shop! ha
Blessings guys and keep up the awesome work!
Stefan
LOVING this build log as well as the comments.
@spacewalker92 - THIS thing looks sweet and I REALLY hope it flies... WE all here at the shop are hoping it SUCCEEDS! ha
@localfiend - That At-At... IS SICK! and I can't wait to see the finished product! You will have to send us one to display at the shop! ha
Blessings guys and keep up the awesome work!
Stefan
TurtlesThatFly
Member
Any progress? I never noticed this build and I want to see what you did so far.
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