XA (3D) with Foam Board Design Challenge

Ligbaer

50 Percenter
now this is on my design list
The 48" series of electronics would also make for a perfect RV8.......!
EDIT: going to try to emulate what flex innovations did by making some changes to the airframes design to make it a little more capable such as bigger control surfaces and a fatter wing. hopefully i will be pleasantly surprised
 
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Jonny Gum

Elite member
now this is on my design list

EDIT: going to try to emulate what flex innovations did by making some changes to the airframes design to make it a little more capable such as bigger control surfaces and a fatter wing. hopefully i will be pleasantly surprised
I'm already on it! Maiden should be Saturday.
 

Jonny Gum

Elite member
I made an interesting discovery...

The Twisted Hobbies Revolto, one of the most respected TH models right now, is a 39" wingspan rocking a motor that is incredibly similar to the Flitetest Pack C motor. It uses an 11x5.5 prop on 3s. I'm now extremely curious as to how well a 39" foam board plane could 3D, seeing as most people probably have a Pack C.

Obviously bigger flies better, but it'd be an interesting experiment. Check this Revolto Video

Also my MX2 broke in half on landing. Bad fuselage design and bad landing gear design. She'll be back.
 

L Edge

Master member
I made an interesting discovery...

The Twisted Hobbies Revolto, one of the most respected TH models right now, is a 39" wingspan rocking a motor that is incredibly similar to the Flitetest Pack C motor. It uses an 11x5.5 prop on 3s. I'm now extremely curious as to how well a 39" foam board plane could 3D, seeing as most people probably have a Pack C.

Obviously bigger flies better, but it'd be an interesting experiment. Check this Revolto Video

Also my MX2 broke in half on landing. Bad fuselage design and bad landing gear design. She'll be back.

If you design right, most things can do hovering.
This was my hardest, a transport.

 

ProfessorFate

Active member
The Sig Something Extra uses a slightly skinny naca 20 airfoil 12-1/16" x 2.5" root plus aileron, tip 10-9/16"x 2 x 3/16" each half = 24"

The SSExtra flew great not draggy 48" ws 2 stroke glo

I experimented with fat airfoils in Real Flight gen3, what about a fat naca 20, 25, or 30?

But, ohhhhh yesssssss, Jonny Gum, that's a super airplane!

Been thinking foam wings using wood ailerons, standard hinges on a wood strip glued to paper flaps from wing. A light foam wing with wood control surfaces.

Extremely fat wings won't allow high speed stalls and neither low speed stalls no matter the wing loading.

I'm thinking of a profile with these ideas

Baby carriage wheels only weigh 1oz but need 1/4" axles
 

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L Edge

Master member
When designing a foam 3D plane, one area that really needs to be looked at is props. It is amazing that a change in the prop can turn an ok plane into a 3D either hovering or doing knife edges.
On a store bought kit(U-Can do) a wide prop, same dia. made it a pleasure to fly doing 3d stuff.
Even found that a CCW prop will work better than a CW wise on some models I have made.
You might want to add that to your list to see if it improves it.
 

Jonny Gum

Elite member
The Sig Something Extra uses a slightly skinny naca 20 airfoil 12-1/16" x 2.5" root plus aileron, tip 10-9/16"x 2 x 3/16" each half = 24"

The SSExtra flew great not draggy 48" ws 2 stroke glo

I experimented with fat airfoils in Real Flight gen3, what about a fat naca 20, 25, or 30?

But, ohhhhh yesssssss, Jonny Gum, that's a super airplane!

Been thinking foam wings using wood ailerons, standard hinges on a wood strip glued to paper flaps from wing. A light foam wing with wood control surfaces.

Extremely fat wings won't allow high speed stalls and neither low speed stalls no matter the wing loading.

I'm thinking of a profile with these ideas

Baby carriage wheels only weigh 1oz but need 1/4" axles
The flex innovations foam aircraft use these fat aerofoils.
 

ProfessorFate

Active member
Hey... good morning Jonny!

How fat have you seen good 3d stunt planes wings? NACA 20, 20% thickness of chord, is fattest library file in profilli airfoil generator program. Real Flite 3.5 let me create any airfoil I wanted, fun to experiment with, I really like THAT particular version 3.5, good modeling aerodynamics

NACA is symmetrical and a regular ratio of chord thickness/chord length


And also I've been looking into sealing foam board. Yesterday:
1: plasti dip, too many coats, made to be able
to be pealed off ...I don't know but they have white at home depot, how you gonna paint over black anyway?

2: pledge floor wax. Rec by Jetman

3: minwax ...oil or water based
Sponz I think rec this with a heavy brown paper application (over the dtf paper??? Or strip and apply???)

What's least trouble cheap and water proofs a good job???

Thank you
Leonard
"Push the button, Max"

Found that 2.7mm x 4'x8' $16 at home depot looks real good weighs about same as lite ply
Here's some pieces of lite ply, bought from Amazon.com 1/8x1x4 sheet $10 each
 

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Jonny Gum

Elite member
Hey... good morning Jonny!

How fat have you seen good 3d stunt planes wings? NACA 20, 20% thickness of chord, is fattest library file in profilli airfoil generator program. Real Flite 3.5 let me create any airfoil I wanted, fun to experiment with, I really like THAT particular version 3.5, good modeling aerodynamics

NACA is symmetrical and a regular ratio of chord thickness/chord length


And also I've been looking into sealing foam board. Yesterday:
1: plasti dip, too many coats, made to be able
to be pealed off ...I don't know but they have white at home depot, how you gonna paint over black anyway?

2: pledge floor wax. Rec by Jetman

3: minwax ...oil or water based
Sponz I think rec this with a heavy brown paper application (over the dtf paper??? Or strip and apply???)

What's least trouble cheap and water proofs a good job???

Thank you
Leonard
"Push the button, Max"

Found that 2.7mm x 4'x8' $16 at home depot looks real good weighs about same as lite ply
Here's some pieces of lite ply, bought from Amazon.com 1/8x1x4 sheet $10 each
I've used minwax on factory made foam models, and have had lots of trouble with it flaking off if the foam get bent at all. However, it should hold much better on foamboard.
 

L Edge

Master member
Here is a flat plate model 31" by 37" built ultra light model that has been reworked a number of times to improve 3D flying.

Having a background in pattern planes and flying pylon, took a look at some areas of improvement Hardest is to set up for both the left and right approaches.
1) lengthen the distance between wing and horizontal tail.


2) shorten nose distance from L E wing.
IMG_0756.JPG

3) flying knife edge, I increased the % area of fuse under wing.
4)changed angle of wing for better flow.
5) reworked % of aileron/wing
6) reworked tail feathers(fixed,hinge line and overhang) especially in hover.
7) explored props(dia and twist) for best performance.

Plane is built ultra lightweight, 3 servos, has a Eflite 370 1200kv with a 9 x 3/4 and 3s 1300lipo. One thickness only of FFF.
Will do the same as video under the hands of a master. Noticed that he does a rolling loop which very few pilots can do, our does the same(not me, my son can).

It is interesting that the Revolt has wing tips.
 

L Edge

Master member
Being ancient(my reaction time and eyesite, especially in a glare) are down.

But here is a video of the performance of the 3D(shown in thread131) showing the basic moves it can do. Plenty of power to pull out of a oncoming crash, and actually can be shown flying slow or fast under the hands of a good pilot. I attempted at least show the capability of inverted, knife edges, hovering and I tried rolling circles. When one can do a knife edge into a least a 10mph wind, stop it's forward movement, have it drop vertically, add power and go forward, this plane will do it. My son taught me this one.

In my opinion, no need to spend hundreds when a cheap foamy will teach you how to do it all. Too expensive with 50 cc or larger.


In gusty wind, some decent knife edges so you know I can(was) good even low.
 
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Jonny Gum

Elite member
I've recently had some new ideas for this thread.

Extreme Flight is releasing new 49" airframes of their Laser and Extra 260 using a new power setup from T-Motor called the AM480 Combo. The setup runs on 6s and swings a 13x6.5 propeller. I think that the ability to design and build a good flying modern style 3D/XA plane at this size is going to be dependent on the electronics inside. In my opinion, a power setup swinging a larger prop effectively will perform better than say a "C Pack" on 4s with a smaller prop at higher RPM. We want strong, smooth thrust. I also know that servos make an incredible difference when it comes to 3D. Having lots of torque, speed, and precision in your servos makes a world of difference. So, I have my eye on the DS17HV from flex innovations as they are reasonably priced with great performance. I have been using them for a year on my 33" JTA profile Slick, and the performance gain from unmarked 9g and Flitetest servos on my last JTA profile is incredible.

In short, I believe that a great flying 39"-50" 3D design with foamboard is entirely possible and I am working with my own ideas of a Laser within this size range. The use of quality and high performance electronics is going to be crucial in achieving this goal.