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basslord1124 RC flight and Flitetest journey/diary - Perkyplanes & RC

Vimana89

Well-known member
More than just a tiny bit of dihedral has a way of clashing with elevons and ailerons. Somebody could probably explain why better than I could, I think it's some sort of adverse yaw if I'm not mistaken. I only see/use moderate or sharp dihedrals on RET from my experience.
 

PoorManRC

Well-known member
More than just a tiny bit of dihedral has a way of clashing with elevons and ailerons. Somebody could probably explain why better than I could, I think it's some sort of adverse yaw if I'm not mistaken. I only see/use moderate or sharp dihedrals on RET from my experience.
With RET Aircraft, you practically NEED Dihedral to maintain any sort of straight line Stability.

(... and I already know that I'm better at THEORY than PRACTICE! But I'm catching up)

Someone with Flying Wing experience will need to better explain it's unusual Flight characteristics.
I DO know that Modern 1:1 Wings (F-117, B-2), use advanced Avionics to manage any inherent instability.

@Hai-Lee That's the reason why the AV-8B Harrier is no longer the "Widowmaker" that the AV-8A or British Electric Mark 1 Harrier was.... Avionics!!

The Lockheed F-104 also had stubby Anhedral Wings too. NO advanced Avionics.... It REQUIRED a certain calibre Pilot - an KILLED 12 of them that didn't respect or couldn't handle her.

In the Right Hands, she was FAST and Maneuverable enough to keep up with several of today's Fighters!

History Lesson over!

I am having Fun. 😉
 

Hai-Lee

Old and Bold RC PILOT
With RET Aircraft, you practically NEED Dihedral to maintain any sort of straight line Stability.

(... and I already know that I'm better at THEORY than PRACTICE! But I'm catching up)

Someone with Flying Wing experience will need to better explain it's unusual Flight characteristics.
I DO know that Modern 1:1 Wings (F-117, B-2), use advanced Avionics to manage any inherent instability.

@Hai-Lee That's the reason why the AV-8B Harrier is no longer the "Widowmaker" that the AV-8A or British Electric Mark 1 Harrier was.... Avionics!!

The Lockheed F-104 also had stubby Anhedral Wings too. NO advanced Avionics.... It REQUIRED a certain calibre Pilot - an KILLED 12 of them that didn't respect or couldn't handle her.

In the Right Hands, she was FAST and Maneuverable enough to keep up with several of today's Fighters!

History Lesson over!

I am having Fun. 😉
Dihedral is for roll stability! If the wings are level then the plane flies straight. When the wings are not level the lift different can cause the plane to turn. You are wise to use dihedral on RET BUT technically it is not required if your plane has sufficient pendulum stability instead or even a gyro stabilized flight stabilization system.

The harrier had anhedral from its first prototype flights, (P1127 and Kestrel), and the anhedral was included in the design to balance the maneuverability. The later avionics upgrades where to help with low speed handling which was atrocious especially when fully loaded, (combat mission profile), due in part to the shadowing of the tail assembly at high AoA. The tail also being subject to increased anhedral and the new Fly by Wire systems helped to solve most of the low speed control issues!

Have fun!
 

PoorManRC

Well-known member
Dihedral is for roll stability! If the wings are level then the plane flies straight. When the wings are not level the lift different can cause the plane to turn. You are wise to use dihedral on RET BUT technically it is not required if your plane has sufficient pendulum stability instead or even a gyro stabilized flight stabilization system.

The harrier had anhedral from its first prototype flights, (P1127 and Kestrel), and the anhedral was included in the design to balance the maneuverability. The later avionics upgrades where to help with low speed handling which was atrocious especially when fully loaded, (combat mission profile), due in part to the shadowing of the tail assembly at high AoA. The tail also being subject to increased anhedral and the new Fly by Wire systems helped to solve most of the low speed control issues!

Have fun!
I'm Old, and do have Brain Farts.... Sometimes I don't communicate exactly what I'm thinking!! 😜

Dihedral IS for Roll Stability, especially in the absence of Ailerons.
BUT, since the theory works by a method of "self adjustment", CAUSING some Banking in turns in the absence of Ailerons....

After the Rudder is returned to the Neutral Position, Lift on the Wing rising in a Turn, is already producing LESS Lift than the other Wing that dipped in the Turn....
Due to the Dihedral making the rising Wing, angle more towards the Vertical plane.

So after the Turn is completed, the Higher Wing wants to Drop - and the Lower Wing, at a flatter angle to INCREASE Lift...

You get a self Stabilization, DUE to the Wing angles wanting to cancel each other's Lift Advantage...

To Promote STABLE, LEVEL, Straight Line Flight! 😉

Still don't believe me?
Try having one Wing with more Dihedral angle than the other. TRY keeping a level, straight course. 😊

..... It's a multipurpose Geometric Solution!
 

Hai-Lee

Old and Bold RC PILOT
I'm Old, and do have Brain Farts.... Sometimes I don't communicate exactly what I'm thinking!! 😜

Dihedral IS for Roll Stability, especially in the absence of Ailerons.
BUT, since the theory works by a method of "self adjustment", CAUSING some Banking in turns in the absence of Ailerons....

After the Rudder is returned to the Neutral Position, Lift on the Wing rising in a Turn, is already producing LESS Lift than the other Wing that dipped in the Turn....
Due to the Dihedral making the rising Wing, angle more towards the Vertical plane.

So after the Turn is completed, the Higher Wing wants to Drop - and the Lower Wing, at a flatter angle to INCREASE Lift...

You get a self Stabilization, DUE to the Wing angles wanting to cancel each other's Lift Advantage...

To Promote STABLE, LEVEL, Straight Line Flight! 😉

Still don't believe me?
Try having one Wing with more Dihedral angle than the other. TRY keeping a level, straight course. 😊

..... It's a multipurpose Geometric Solution!
Should you have a plane with a strange wing set where one wing sits on the fuselage at a different dihedral angle to the other, any turning issues you experience are not actually due to the dihedral angles as the wings will find a balance of lift Vs weight centre BUT unless your plane has a 0-0, (Wing,tail), incidence angle setup the apparent twisted or altered tail angle, (due to the wings trying to self level), can apply a sideways force unless the aerodynamic loading is also absolutely zero.

With a loaded tail, (either positive or negative), the different angle between the tail and the wing level mean will equate to a side force generated by the elevator/horizontal tail, (EVEN in level flight or any attempt thereof). The Nett lift is normally calculated as being at right angles to the horizontal surface or on the mean centre line between "V" tail members.

You can negate such an occurrence when the wings do not sit correctly by Shimming the wing saddle to have the wings return to equal angles with respect to the horizontal tail member.

The laws of aerodynamics are somewhat fixed and an aircraft flies best when all of the aerodynamic forces are in balance, (None can be ignored in the balancing act)!

Have fun!
 

basslord1124

Well-known member
@Hai-Lee or @mayan , perhaps either one of you all can help me here.

I printed out and put together the plans for the KFM wing, but I didn't realize the plans would end up being just a tad bit bigger than a sheet of foamboard. Here's a pic:

kfm plans resize.jpg

You can see how the plans extend past the foamboard by an inch of 2 (upper right). Did I do something in my printout of the plans OR do I need to scale it down? I noticed that a few places didn't line up the best. I suppose I am so used to doing FT plans that I'm not as familiar with "non-FT" plans and how to work with them. I feel like this is one of those rookie/newbie mistakes or something and that I should know better.
 

mayan

Well-known member
@Hai-Lee or @mayan , perhaps either one of you all can help me here.

I printed out and put together the plans for the KFM wing, but I didn't realize the plans would end up being just a tad bit bigger than a sheet of foamboard. Here's a pic:

View attachment 140120

You can see how the plans extend past the foamboard by an inch of 2 (upper right). Did I do something in my printout of the plans OR do I need to scale it down? I noticed that a few places didn't line up the best. I suppose I am so used to doing FT plans that I'm not as familiar with "non-FT" plans and how to work with them. I feel like this is one of those rookie/newbie mistakes or something and that I should know better.
They actually look bigger than mine. Did you make sure to print a 100% scale?
 

Wildthing

Well-known member
Really? I'm pretty sure I did 100% scale. And then I did a poster print which gave me 15 pages I believe.
Just cut the plans apart and reposition on the FB , some of the smaller pieces may have to go onto a second sheet or god knows we always have a ton of scrap pieces. I will a lot of the times cut the plans apart so I can try to use up the scrap first leaving bigger leftover pieces from the new sheet.
 

basslord1124

Well-known member
Then you didn’t print 100% should be ~9 pages! Also try positioning on an off side. :).
I just did a reprint and got 12 pages total. About 9-10 of those actually take up the wing plans...the other pages are just extra blank sheets. Haven't tape it together yet, but I'd say this is it now. Not sure what happened last time.
 

basslord1124

Well-known member
Actually on looking at it again...the first time I printed, all tiles printed portrait and I got 15 total pages. Now I am getting 12 total pages and all the pages are printing landscape (which if I print landscape it will take less paper). Here are my print settings:

print settings.JPG

So you can see, the scale is 100%. In the original thread, @Hai-Lee mentioned that the wingspan was 800mm, which is actually almost 31.5"...Adams Readi-Board (which is what I am using) is 30" wide. So, it looks like I really will have to scale it down just a hair to fit Adams foamboard.
 

Hai-Lee

Old and Bold RC PILOT
Are you saying rather than lay it horizontal on the foam board to angle it...like from lower left corner to upper right corner? (Kinda like how they measure LCD TVs)
I just measured one I have yet to finish and without the winglets the wing measures 795mm from tip to tip, Spanwise!

You may have a slight translation error have you measured the printed scale to see if the scale is the correct size?

If you need to scaling the plans in a minor reduction will make little difference!

Have fun!
 

basslord1124

Well-known member
I tried it @mayan and even removed some excess paper...it still goes past the foamboard.

angled kfm plans.jpg

You can see here that the right side goes past the foamboard as does the nose (even though the paper is folded up a tad).

This is off a work printer...tempted to try other printers and other printer settings.