Is foamboard really too heavy?

[SSgt Duramax]

You know, when I participate in forums outside of here to discuss my other planes, in particular when it comes to scratch building, there are lots of folks (who typically aren't pro foam board) who claim that foam board is too heavy. Then, upon investigation of their builds, pretty much every single one of their planes of similar size to mine are bricks in comparison.

I see similar sized balsa and other foam planes that are heavier than mine all the time. So what gives?

Are they only using the heavy foamboard? Are they building it with 700lb of hot glue? Or do they just not like the stuff?

For instance, my Mig 29 is about a half pound lighter than the lightest 50mm twinjet I can find.

My FT p40 was about a pound lighter than the 1100mm banana hobby one.

My EPP planes are considerably heavier than their DTFB counterparts.

I know there are methods you can use to get lighter, and I know that it definitely is easier to get "true scale" by other means, but I don't quite get it.

The way I see it, is foam board does a lot of things decently well, but nothing particularly well. It is very cheap, and you can do some neat things with it, and build a whole airframe for south of $10, but if you want true to scale, or something feather weight, you should probably pick something else, or combine it with 3d printing or fiberglass.... which is pretty much what balsa people do anyways.

 

[Pieliker96]

I've measured a 20"x30" of Adam's Readi-Board (DTFB) at 110g / ~60g (with paper / no paper). The Elmer's stuff is north of 150g/sheet, as are most other brands I've seen out there. Certainly the type of board plays a role, as does the amount of glue used.

Construction style certainly has a good bit to do with it. I've found that my more geometrically complex designs (fuselages with formers, rounded corners, rib and spar construction, very little traditional A/B/C folds) tend to overshoot their weight targets by a more considerable margin than the simpler designs. Geometric and mechanical complexity seems to come at the expense of weight, as does building with foam using structural techniques developed for other materials.

Design determines weight as much, if not even more so, than material choice. Box fuselages and flat-bottom, fold-over wings so characteristic of the FT style are considerably lighter than much any other alternative - in order to produce a sufficiently lightweight result, design must be done in accordance with the material properties. It's possible some of the excessively heavy builds you've seen were done in design styles better suited to different materials, or had unnecessary reinforcement due to an unfamiliarity and lack of intuition of the mechanical properties of DTFB.

 

[Hondo76251]

I agree, outside the FT comunity there is a strange resistance to foamboard it seems. Also agree a lot of people dont know how to use it in the best ways.

In my area at least, the only people who fly models, to use a term longingly transfered from the gun world, are fudds. Nothing but the same old things they have always done and used are going to be warmly accepted. Is this the case on a national scale? Dont know, but it can't help.

The beauty of foamboard, along with the availability of relatively cheap quality electronics, is that it makes the hobby so much more accessible. The more people we have the more of a voice we can put to the bad legislation heading our way...

 

[Flying Monkey fab]

You know, when I participate in forums outside of here to discuss my other planes, in particular when it comes to scratch building, there are lots of folks (who typically aren't pro foam board) who claim that foam board is too heavy. Then, upon investigation of their builds, pretty much every single one of their planes of similar size to mine are bricks in comparison.

I've seen this everywhere in life, in maned flight in everyday life. People want to think what they have invested their time and money in is the best. Simple conformation bias.
There is no best—more about what you want to do and the size you wish to, etc. I like foam board because it is so inexpensive and quick to build with, but I can see where there would be a pride factor in doing a nice balsa model.
When I have more time (retirement), I'd love to start hot wiring foam block for better scale, but I'd never claim it is intrinsically better.

 

[SSgt Duramax]

I've seen this everywhere in life, in maned flight in everyday life. People want to think what they have invested their time and money in is the best. Simple conformation bias.
There is no best—more about what you want to do and the size you wish to, etc. I like foam board because it is so inexpensive and quick to build with, but I can see where there would be a pride factor in doing a nice balsa model.
When I have more time (retirement), I'd love to start hot wiring foam block for better scale, but I'd never claim it is intrinsically better.

I am not questioning the superior aesthetics. I'm also not at the point where I want a plane as nice as my car, and it is the end of the world when it gets crashed.

EPP is great stuff. Very hard to break, and I want to start using it more. But it is heavier.

Balsa is beautiful, but it is fragile. It isn't like the whole plane is made out of balsa though. Those nice curvy cowls and canopies (and maybe select other things) are made out of fiberglass or vacuum formed plastic. No different than sticking 3D printed parts to a foamie.

If I find a decent deal on a balsa kit, I will buy it, they are very rewarding. Balsa prices these days are $$$.

 

[Tench745]

This is my assumption of what happened:
Someone built a foamboard model. They were probably an accomplished balsa builder, so they are respected as a competent authority. They over-built to compensate for perceived flaws in the material or to add detail. The plane wound up heavy. They told their friends.
And now you have a respected authority on building saying foamboard builds heavy; people don't want heavy planes so they don't build their own and pass on the "because foamboard is heavy" advice they got.

We all know that foamboard has its pros and cons. One of them is that it is a sheet material like plywood is. This is great for making really light stressed-skin structures like wings. Balsa has its pros and cons too. It is great for strong, engineered structures like a truss style fuselage, and the grain runs along the force axis, so all that open truss-work will almost always be lighter and stronger than a plywood or foamboard structure.
If you use a material that isn't ideal for a specific structure you will end up making it heavier to compensate. But, if you combine the use of those same materials in a way that maximizes their strengths you can have a plane even lighter than either method alone. The trick is knowing those strengths and how to use them together.

I think there is also a size range where foamboard is ideal. If you go too small you end up with solid foamboard and the plane is heavy. If you go too big the foamboard can't handle the forces involved and needs extra reinforcement.

I'd like to end with a real-world example of how foamboard is "heavy" (ie. the same plane can be built lighter). This is my FT-Sea Angel, built with all paper removed. My build has a larger/heavier motor, carbon-fiber wing spars (to make up for the loss of rigidity from removing the paper), extra detailing on the engine nacelle and cockpit, a pilot figure, and a full paint job.

I added a whole bunch of detail and came out with an empty weight of 535grams (18.87oz).
By comparison, the published empty weight for the FT Sea Angel is 635g (22.4oz) So I saved over 100g by building without hot glue and without the paper.

It hasn't flown yet, so it could still be a complete failure, but it looks and feels pretty good to me.

Another benefit of building with just the foam, you can sand in curves!

 

[Merv]

...and build a whole airframe for south of $10....

I think that is at the heart of the matter.

From time to time I get to a really nice AMA field. There are people there who have beautiful planes costing hundreds of not thousands of dollars. I show up with my $10 flite test foamboard planes. They will snicker at me until they see them fly. Then all of the snickering stops when they recognize my planes fly just as good as theirs. I'm having just as much fun with my $10 plane as they are with theirs.

They are just making excuses to justify why they are spending sooo much money on their plane.
It's kinda like high school, the cool kids "need" to have the $200 sneakers when the $20 ones work just as well.

 

[Hondo76251]

I tried a lot of different ways to to an all foamboard micro plane thay still looked scale. Its tricky and ive had only marginal success.
My "black magic " turned out pretty neat but not exactly a joy to fly.


Might try again in the future with brushless but thats a lot of wires in a very small space.



Clearly, with foamboard, the "less scale" EZ pack style of building is superior and with 1s brushed power a true 4 servo twin engine plane is pushing the limits. I'm happy it could fly at all. Its so close to working well that even talking about it is tempting me to try again lol.

Balsa might be a better fit but this is literally pennies worth of foam and paper, nearly indestructible, and only about an hours worth of work the way i do it. (Excluding the wiring of course)

 

[SSgt Duramax]

I think that is at the heart of the matter.

From time to time I get to a really nice AMA field. There are people there who have beautiful planes costing hundreds of not thousands of dollars. I show up with my $10 flite test foamboard planes. They will snicker at me until they see them fly. Then all of the snickering stops when they recognize my planes fly just as good as theirs. I'm having just as much fun with my $10 plane as they are with theirs.

They are just making excuses to justify why they are spending sooo much money on their plane.
It's kinda like high school the cool kids, "need" to have the $200 sneakers when the $20 ones work just as well.

Yeah, I guess it depends on where your goals are in the hobby I suppose. I once thought that I wanted to work my way up to a thousands of dollar turbine jet. Now I could really care less, and I think I can have plenty of fun without it. I actually don't have a ton of interest in having an extremely expensive plane, and that could change.

The way I see it, is having a really expensive model is kind of like being the principal of a homeschool. You're really cool inside that small select group of individuals, you have power, authority, and a $10,000 toy that 99.9% of people will never see operate or fly. If an outsider does see it, you certainly wouldn't want them to touch it or even look too hard at it. I'm not trying to pigeon hole folks with really expensive planes into being jerks or anything, I know not everyone is like that, they just do it because that is what they like, and don't care what everyone else thinks.

 

[SSgt Duramax]

I tried a lot of different ways to to an all foamboard micro plane thay still looked scale. Its tricky and ive had only marginal success.
My "black magic " turned out pretty neat but not exactly a joy to fly.
View attachment 224695 View attachment 224696

Might try again in the future with brushless but thats a lot of wires in a very small space.

View attachment 224697 View attachment 224698

Clearly, with foamboard, the "less scale" EZ pack style of building is superior and with 1s brushed power a true 4 servo twin engine plane is pushing the limits. I'm happy it could fly at all. Its so close to working well that even talking about it is tempting me to try again lol.

I don't know what size you want, but I have successfully built a 20" DTFB plane that flew well. Although I wouldn't call it light and floaty. You need to depaper one side of everything, and don't even look at the hot glue gun.

Mine ran a 1407/2800kv with a 5040 prop. It wasn't exactly light and floaty, but it was easy enough to fly. Very fast too.

 

[Hondo76251]

Yeah, I guess it depends on where your goals are in the hobby I suppose. I once thought that I wanted to work my way up to a thousands of dollar turbine jet. Now I could really care less, and I think I can have plenty of fun without it. I actually don't have a ton of interest in having an extremely expensive plane, and that could change.

The way I see it, is having a really expensive model is kind of like being the principal of a homeschool. You're really cool inside that small select group of individuals, you have power, authority, and a $10,000 toy that 99.9% of people will never see operate or fly. If an outsider does see it, you certainly wouldn't want them to touch it or even look too hard at it. I'm not trying to pigeon hole folks with really expensive planes into being jerks or anything, I know not everyone is like that, they just do it because that is what they like, and don't care what everyone else thinks.

Haha, agreed.

I do this because i love flying and dont have the time or funds to do it for real lol.

How do we stack up in the hierarchy, those of us that use a foamboard airframe to fly a thousand dollars worth of electronics around! ? 🤪😂

 

[Hondo76251]

I don't know what size you want, but I have successfully built a 20" DTFB plane that flew well. Although I wouldn't call it light and floaty. You need to depaper one side of everything, and don't even look at the hot glue gun.

Mine ran a 1407/2800kv with a 5040 prop. It wasn't exactly light and floaty, but it was easy enough to fly. Very fast too.

For arbitrary reasons this project started as a brushed twin that used old toy quad parts. The personal building challenge is to make a real 4 or 5 channel plane that uses the 8mm brushed motors. Just a touch bigger and a little bit more power would indeed go a long way towards making it easier to fly... 😉

I've built a ton of planes that are easy to fly, whats the fun in that! 😂

 

[SSgt Duramax]

Haha, agreed.

I do this because i love flying and dont have the time or funds to do it for real lol.

How do we stack up in the hierarchy, those of us that use a foamboard airframe to fly a thousand dollars worth of electronics around! ? 🤪😂

I was flying my night fury one day realizing that the electronics in it were worth 40 times more than the airframe... lol.

 

[Taildragger]

You know, when I participate in forums outside of here to discuss my other planes, in particular when it comes to scratch building, there are lots of folks (who typically aren't pro foam board) who claim that foam board is too heavy. Then, upon investigation of their builds, pretty much every single one of their planes of similar size to mine are bricks in comparison.

I see similar sized balsa and other foam planes that are heavier than mine all the time. So what gives?

Are they only using the heavy foamboard? Are they building it with 700lb of hot glue? Or do they just not like the stuff?

For instance, my Mig 29 is about a half pound lighter than the lightest 50mm twinjet I can find.

My FT p40 was about a pound lighter than the 1100mm banana hobby one.

My EPP planes are considerably heavier than their DTFB counterparts.

I know there are methods you can use to get lighter, and I know that it definitely is easier to get "true scale" by other means, but I don't quite get it.

The way I see it, is foam board does a lot of things decently well, but nothing particularly well. It is very cheap, and you can do some neat things with it, and build a whole airframe for south of $10, but if you want true to scale, or something feather weight, you should probably pick something else, or combine it with 3d printing or fiberglass.... which is pretty much what balsa people do anyways.

Sounds like my friend’s dad who only flies foam ARFs because “balsa planes are too heavy”. He’s never had a successful flight with a balsa plane so I think he might be biased lol

 

[Ryan O.]

I’m lucky enough to fly at a field where just about everything from $10 foam board planes to FPV mini quads to Turbines are flown, and thanks to the club having an annual foam board/pizza box plane competition most of the good balsa builders have given it a try by now with pretty good success, but it seems my field is the exception, not the rule. I do agree with previous comments saying that balsa builders tend to over engineer their foam board planes since at first nearly everyone used really overbuilt planes with heavy wing spars, wings with too many score cuts that made folding too hard, and beefy landing gear but anyone who built their second or third plane made everything much simpler and lighter.

 

[Taildragger]

I’m lucky enough to fly at a field where just about everything from $10 foam board planes to FPV mini quads to Turbines are flown, and thanks to the club having an annual foam board/pizza box plane competition most of the good balsa builders have given it a try by now with pretty good success, but it seems my field is the exception, not the rule. I do agree with previous comments saying that balsa builders tend to over engineer their foam board planes since at first nearly everyone used really overbuilt planes with heavy wing spars, wings with too many score cuts that made folding too hard, and beefy landing gear but anyone who built their second or third plane made everything much simpler and lighter.

my fields about the same, we have just about everything but I have seen that's not the case with a lot of them

 

[SSgt Duramax]

Sounds like my friend’s dad who only flies foam ARFs because “balsa planes are too heavy”. He’s never had a successful flight with a balsa plane so I think he might be biased lol

The only two balsa planes I've flown I buddy boxed at the local club way back in the day and they flew great. They were hands off flying big old nitro planes though, so I guess it is to be expected.

I honestly don't put most of my planes on the scale though, I don't think it matters. Actually, I stress when my planes are heavier than they are supposed to be. The first FT P-40 I built was well overweight, I minwaxed/painted the heck out of it and ran the motor similar to the FT 2814 radial with a bigger than average battery. I weighed it and though holy cow, that is way heavier than I imagined. Had I know the plane was about 8oz heavier than it "should have been" I probably would have been doubting the success of it the whole time. But time after time I would just hold it up over my head, throttle it up, and open my hand and it would sail out of my hand without a toss like it weighed nothing.

I figured out then weight, while it matters, isn't the end all be all. Obviously a glooped up foamwad won't fly well, but if it is "good weight" it doesn't matter a ton.

 

[Hondo76251]

I dont mind a little extra weight when im flying FPV, helps smooth things out. Helps with wind too.

For all the debates about power, best prop, cubic wing loading, etc. Its seems theres a pretty wide envelope for what can actually fly. As long as you get a good feel for the CG you can get most anything into the air!

 

[luvmy40]

I think some of the "Foam is Heavy" comes from the Hobby Lobby/ Walmart Elmers foam boards. They are decidedly heavier than Adams Redi Board, which has already been stated. I'm sure it is also a dinosaur thing too. "That's not what I learned to build with!"

So, I have built exactly 1 balsa plane, and that was 45 years ago. It was a wire controlled wing called the L'il Satan with the Cox 0.49 Black Widow stunt engine. I later converted it to RC but never flew it as RC because I couldn't afford the radio.

Fast forward to last Christmas season, when I discovered Flite Test. My wife bought me the Simple Cub value bundle and I haven't stopped building since. I don't get to fly much, and when I do it's fairly comical, but then I get to come home and build it again!

I do have a very nice balsa kit that was gifted to me. I may, someday build it but I'm not holding my breath. The instant gratification of cutting and assembling the foam planes is quite nice.

 

[OliverW]

I’m lucky enough to fly at a field where just about everything from $10 foam board planes to FPV mini quads to Turbines are flown, and thanks to the club having an annual foam board/pizza box plane competition most of the good balsa builders have given it a try by now with pretty good success, but it seems my field is the exception, not the rule. I do agree with previous comments saying that balsa builders tend to over engineer their foam board planes since at first nearly everyone used really overbuilt planes with heavy wing spars, wings with too many score cuts that made folding too hard, and beefy landing gear but anyone who built their second or third plane made everything much simpler and lighter.

Most fields are that way where they don't care what you fly, just that you're flying! Its just the handful that are against it you hear all about...