Most of the foam planes are made with EPS or "beer cooler foam" EPP or equivalent like foam is so much more sturdy an reistant to dings and crashes.
Multiplex and Walkera use it. I dont have to glass it unlike EPS.

It's heavy and flexible.

Flying works better when the material is light and rigid.

There are manufacturing and cost issues, too, but forme the weight and rigidity are most important. I can glass it and end up stronger, stiffer, and still lighter and cheaper than EPP.

The biggest reason we don't see more EPP planes is that EPP doesn't work well in an injection molds for big production runs. It tends to get a heavy skin in the mold and stick to the mold.

Most of the EPP planes are wire cut one at a time making EPP an expensive material to work with. EPP is more flexible for its weight so it requires spars and structure reinforcing.

The advantages of EPP are significant. Try this with an EPO or EPS plane.

RC Plane Crashes into Brick Wall in Slow Motion. (7 min 31 sec)

Wow, if only you could see in to the future, nowadays almost every production foamie is made of EPP - to the naysayers, shame on you

Originally Posted by Lee

The biggest reason we don't see more EPP planes is that EPP doesn't work well in an injection molds for big production runs. It tends to get a heavy skin in the mold and stick to the mold.

Most of the EPP planes are wire cut one at a time making EPP an expensive material to work with. EPP is more flexible for its weight so it requires spars and structure reinforcing.

The advantages of EPP are significant. Try this with an EPO or EPS plane.

https://www.youtube.com/watch?v=HgGtMrgPgR8

Why don't you try it with EDF jet, lets see how it goes. BTW, this is EDF Forum, not Flying wings! LOL.

We have had quite a few flyers put EDFs on flying wings some of them scale builds of military and WW2 Horton planes and others with research planes others just for fun. Jets and flying wings go together and are something different. They are "Foamy EDFs"

https://www.google.com/search?sxsrf=...w=1920&bih=937

https://en.wikipedia.org/wiki/Horten_Ho_229

https://www.google.com/search?sxsrf=...w=1920&bih=937

Originally Posted by FlyMachine Art

Wow, if only you could see in to the future, nowadays almost every production foamie is made of EPP - to the naysayers, shame on you

No they’re EPO.
Three different materials here:
EPP is expanded polypropylene, the stuff they use in bouncy gliders and inside cyclists’ crash helmets, and is typically cut with a hot wire in model airplane applications.
EPO is expanded poly olefin, this is what most production foamies are moulded out of.
EPS, which is expanded polystyrene, the “beer cooler” foam that most of our planes arrive packaged in.

Originally Posted by FlyMachine Art

Wow, if only you could see in to the future, nowadays almost every production foamie is made of EPP - to the naysayers, shame on you

They are all made of EPO.

Originally Posted by bandetlol

They are all made of EPO.

MOST are EPO... Some profile planes and wings are EPP. There are still a few EPS planes around too, such as Freewing's SU-35, but not many.