Help! How do i make molded planes?

RossFPV

Well-known member
Im trying to make a Wendell Williams model 44 with foamboard and i got the formers printed but i dont know how to make the skins. i dont need plans because this is a one-time build, any idea how to do it?
 

FlyerInStyle

Elite member
Also just a tip, you should just make a compilation of all the video's, with unimportant parts cut out, as I tried designing a plane by your videos, and it was really helpful, but a little too long for me to design. I would prefer to just see instructions, and do myself, not seeing you adjusting everything. I think that part adds about 15 min per video, which is a lot. Just a tip. Don't listen if you don't want to.
 

Whit Armstrong

Elite member
Also just a tip, you should just make a compilation of all the video's, with unimportant parts cut out, as I tried designing a plane by your videos, and it was really helpful, but a little too long for me to design. I would prefer to just see instructions, and do myself, not seeing you adjusting everything. I think that part adds about 15 min per video, which is a lot. Just a tip. Don't listen if you don't want to.

Yeah, I should do that. Maybe when I have some time over christmas break.
 

mastermalpass

Master member
For finding the skin shapes, if you already have the formers, stick those formers to each other with the same space between them as they would have on the model and use this awesome technique:


If instead you need tips bending the foamboard without snapping it, here's what I know:
1) My foam is much more likely to snap one way than the other. Cut a strip and see which way yours bends easiest.

Screenshot_20221206-215956_Drive.jpg


2) FliteTest foamboard needs the paper removed from the inside.

3) Bending methods:
3i. Place board on a table/desk/worksurface and drag it off the side slowly, bending it around the edge gently and easing it in over time. This is the technique Overstreet uses, I think.

Screenshot_20221206-215646_Drive.jpg


3ii. For easier, faster bending, you want a rolling tube. Peter Sripol has something that seems like a clothes rail - but the rail can spin of course.

3iii. I put together a little machine for foam bending. Two copper pipes held in place, but able to Roll then a third copper pipe to press the foam down between the first two. Makes it easier to spread the force and get an even curve. I even made it so that the distance between the bottom two pipes was adjustable, but I never find myself needing to adjust it.

Screenshot_20221206-215638_Drive.jpg


The only problem is the poorly made wooden mounts that hold the bearings on the pipes. The bearings are often slipping out of the mounts. Thing is, just putting two pipes on the work bench and pressing foam into them with a third pipe is easier than the edge of the bench.
 

RossFPV

Well-known member
For finding the skin shapes, if you already have the formers, stick those formers to each other with the same space between them as they would have on the model and use this awesome technique:


If instead you need tips bending the foamboard without snapping it, here's what I know:
1) My foam is much more likely to snap one way than the other. Cut a strip and see which way yours bends easiest.

View attachment 232741

2) FliteTest foamboard needs the paper removed from the inside.

3) Bending methods:
3i. Place board on a table/desk/worksurface and drag it off the side slowly, bending it around the edge gently and easing it in over time. This is the technique Overstreet uses, I think.

View attachment 232740

3ii. For easier, faster bending, you want a rolling tube. Peter Sripol has something that seems like a clothes rail - but the rail can spin of course.

3iii. I put together a little machine for foam bending. Two copper pipes held in place, but able to Roll then a third copper pipe to press the foam down between the first two. Makes it easier to spread the force and get an even curve. I even made it so that the distance between the bottom two pipes was adjustable, but I never find myself needing to adjust it.

View attachment 232739

The only problem is the poorly made wooden mounts that hold the bearings on the pipes. The bearings are often slipping out of the mounts. Thing is, just putting two pipes on the work bench and pressing foam into them with a third pipe is easier than the edge of the bench.
Thank you for the detailed response! i will definitely look into fusion 360 and the rollation method, this will be very helpful!
 

quorneng

Master member
My solution to double curvature skinning in thin sheet foam is 'planking'.
The Wendell Williams model 44 fuselage is almost a straight taper from the engine to the tail so the individual plank shape is not too complex and each plank shape can be adjusted as you go along.
If you already have the formers cut then cut them in half vertically and fix them to a board at the correct positions.
Then slowly cover the formers with long narrow tapered strips of foam gluing each to all the formers and to its neighbour.
An example of the process.
The first plank on the half formers. In this case the formers are just 'rings' for minimum weight.
HalfNose1.JPG
The completed planked half shell. As each plank is narrow it does not require much force (note the pins!) to hold it to shape.
HalfNose2.JPG
The completed half shell lifted from the board when the glue has dried.
HalfNose3.JPG
The other half of the formers added and planking started
FuseNose1.JPG
The completed nose of an airliner in 3 mm foam except the 3D printed nose cone
NoseCmplt2.JPG
With a bit of filling , sanding and paint the planking is no longer visible.
Nose.jpg
It looks like a one piece moulding. No CAD is required just a 3 view drawing blown up to the required size. :)
I have 19 different scale planes, both big and small, with planked foam fuselages.
 
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Mr NCT

Site Moderator
My solution to double curvature skinning in thin sheet foam is 'planking'.
The Wendell Williams model 44 fuselage is almost a straight taper from the engine to the tail so the individual plank shape is not too complex and each plank shape can be adjusted as you go along.
If you already have the formers cut then cut them in half vertically and fix them to a board at the correct positions.
Then slowly cover the formers with long narrow tapered strips of foam gluing each to all the formers and to its neighbour.
An example of the process.
The first plank on the half formers. In this case the formers are just 'rings' for minimum weight.
View attachment 232742
The completed planked half shell. As each plank is narrow so it does not require much force (note the pins!) to hold it to shape.
View attachment 232743
The completed half shell lifted from the board when the glue has dried.
View attachment 232744
The other half of the formers added and planking started
View attachment 232745
The completed nose of an airliner in 3 mm foam except the 3D printed nose cone
View attachment 232746
With a bit of filling , sanding and paint the planking is no longer visible.
View attachment 232748
It looks like a one piece moulding. No CAD is required just a 3 view drawing blown up to the required size. :)
I have 19 different scale planes, both big and small, with planked foam fuselages.
Good idea, like making a wooden boat hull.
 

EdwardA

New member
My solution to double curvature skinning in thin sheet foam is 'planking'.
The Wendell Williams model 44 fuselage is almost a straight taper from the engine to the tail so the individual plank shape is not too complex and each plank shape can be adjusted as you go along.
If you already have the formers cut then cut them in half vertically and fix them to a board at the correct positions.
Then slowly cover the formers with long narrow tapered strips of foam gluing each to all the formers and to its neighbour.
An example of the process.
The first plank on the half formers. In this case the formers are just 'rings' for minimum weight.
View attachment 232742
The completed planked half shell. As each plank is narrow it does not require much force (note the pins!) to hold it to shape.
View attachment 232743
The completed half shell lifted from the board when the glue has dried.
View attachment 232744
The other half of the formers added and planking started
View attachment 232745
The completed nose of an airliner in 3 mm foam except the 3D printed nose cone
View attachment 232746
With a bit of filling , sanding and paint the planking is no longer visible.
View attachment 232748
It looks like a one piece moulding. No CAD is required just a 3 view drawing blown up to the required size. :)
I have 19 different scale planes, both big and small, with planked foam fuselages.

I've been considering something almost identical. Are your 3 or 6mm? ...and did you coat or reinforce them?

Thanks
 

quorneng

Master member
Edward A
The whole plane in my example is 3mm. It is not coated in any way apart from the acrylic paint.
As an airliner the fuselage is big enough to be strong and rigid enough despite being so long.
Q400Complete.JPG

The fuselage was built in 3 sections glued together. A nose, a tail and a long parallel middle. The wing sits on top of the fuselage.
The wing is also 3 mm but it does have quite a substantial hard balsa spar to carry the motor nacelles. Each nacelle also carries a flight battery. The Rx is in the wing root, the servos are all close to their respective surfaces so the fuselage is completely empty!

When I saw a full size Bombardier Q400 fly over the white wings looked ridiculously small to support the obvious purple fuselage. I just had to build one!
 

EdwardA

New member
Edward A
The whole plane in my example is 3mm. It is not coated in any way apart from the acrylic paint.
As an airliner the fuselage is big enough to be strong and rigid enough despite being so long.
View attachment 232799
The fuselage was built in 3 sections glued together. A nose, a tail and a long parallel middle. The wing sits on top of the fuselage.
The wing is also 3 mm but it does have quite a substantial hard balsa spar to carry the motor nacelles. Each nacelle also carries a flight battery. The Rx is in the wing root, the servos are all close to their respective surfaces so the fuselage is completely empty!

When I saw a full size Bombardier Q400 fly over the white wings looked ridiculously small to support the obvious purple fuselage. I just had to build one!

It looks pretty good!

What's the weight? The reason I was asking about reinforcement is because I'm expecting around 8 lbs AUW and I'm considering, will the fuse support handling it.... putting it in my hatchback, etc. I won't be able to remove the wings for transport but it's configured more like a fighter jet. The fuse is longer than the wing span....by maybe a foot or more.

Thanks
 
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quorneng

Master member
Edward A
For its size it is light, under 2 lbs.
It would asking quite a lot for an unreinforced foam skin fuselage to manage an 8lb all up unless the fuselage was pretty fat and foam thicker, 6 mm?
 

EdwardA

New member
Edward A
For its size it is light, under 2 lbs.
It would asking quite a lot for an unreinforced foam skin fuselage to manage an 8lb all up unless the fuselage was pretty fat and foam thicker, 6 mm?

Yeah, that's what I guessed. On my previous version, I used carved out xps (foamular-150). Works pretty well, but I'm looking everywhere possible for weight savings.... maybe a combination of materials where needed. I have 3 and 6mm depron sheets on hand.

There are places in the carved out xps that I can go significantly thinner, other areas, not. That's a difficult way of doing it. 5" cylinder a bit more than 5' long.

Great job on the Q400!

... sorry, didn't wanna highjack this guy's thread.
 
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FlyingTyger

Elite member
You could make a simple subframe inside that would tie all the structural parts together. Then the planked body could be built around it. That way that portion doesn't have to carry any of the loads, it's just along for the ride.
And a layer of lightweight fiberglass and resin can go along way to make the outside skin tougher and less prone to hangar rash.
 

RossFPV

Well-known member
Yeah, that's what I guessed. On my previous version, I used carved out xps (foamular-150). Works pretty well, but I'm looking everywhere possible for weight savings.... maybe a combination of materials where needed. I have 3 and 6mm depron sheets on hand.

There are places in the carved out xps that I can go significantly thinner, other areas, not. That's a difficult way of doing it. 5" cylinder a bit more than 5' long.

Great job on the Q400!

... sorry, didn't wanna highjack this guy's thread.
Im perfectly fine with you using my thread! This information could be useful for others in future!
 

mastermalpass

Master member
Works pretty well, but I'm looking everywhere possible for weight savings.... maybe a combination of materials where needed. I have 3 and 6mm depron sheets on hand.

One trick for me is the use of two-part epoxy in place of hot glue. It's a stronger bond for a good amount less weight.