Hi guys, now my son is old enough to enjoy going to indoor flying at nights with me, I want to build some nice looking models. I was brought up on stick & tissue FF rubber models as a kid, and really enjoy building them, but now I'm seeing some guys doing amazing things with vac-formed 1mm Depron. As weight is the key to success with micro stuff, I was wondering if anyone has done a proper study to see which is lighter. I'm thinking in the 12-18" span range, anything from a WW1 bipe to a WWII fighter. Sure, that's a big range and what may work for a slow bipe may not be the best for a Spitfire. What I like about vac-formed Depron is that once you have the moulds you can make a dozen vac-formings in one sitting, and build say 2-3 models all at once, not to mention the end result can look quite stunning, esp if it's something like a WWII fighter. Stick & tissue has a special appeal for WW1 bipes, but perhaps not durable enough for indoor flying in small sites. Any input would be great to hear, thanks!

Stu.

well they are very different mediums. getting a stick and tissue pretty is very easy. getting a foam pretty is very hard. vaccume forming foam is not something i have heard much of. any links?

most people that i have seen molding foam are using heat and pressure molds.

if its your son, id say get (or build) an ugly foamy that files well. he will be crashing alot. stick and tissue si very pretty, but very fragile.

tho for straight out weight, id say balsa. tho it would be to fragile to take any hard landing.
foam is your best bet, unless you got bird like piloting skills or like building more that flying.

if you can get it down right, the foam will be lighter for the same strength level. you can build lighter with balsa, but to get there, you lose durability and REPAIR ability. one bad stick movement and you get a pile of sticks, with foam, you just glue the broken pieces back in place and go fly in a few minutes

also, if you used a plastic model kit, you can get all the surface details that would take LOADS of time to get in balsa.

what derk said. i tend to talk too much!

If we're talking about the suitability and durability of 1mm vacuum formed models versus balsa stick and tissue models for a kid, I'm not sure there's a difference.

Both are about as delicate. Both have similar mass, rigidity, etc.

I can say that given the choice, I'd personally rather make repairs on balsa models than 1mm depron non-profile models.

When I damage a balsa model I can very precisely remove broken spars/ribs/etc and replace them, returning the model to its exact original state. It'll take a bit of time and I won't be in the air again with that plane during that session. But it will be like the damage was never there.

When I damage a formed sheet foam model I can't return the damaged part to its original state without replacing the entire part. Imagine a wing with a chunk taken out of the leading edge. To make it "perfect", I need to replace the wing. To make it flyable again I can cut out the damage and glue in a patch. The more patching I do, the heavier the plane gets.

In the end it's a tradeoff. If you're not crashing a lot, balsa is great. If you are, foam is great.

My suggestion: increase your options a bit.

For example, profile foamies are very forgiving when it comes to making repairs and are even something most kids can make themselves with a bit of help.

Consider designs like the nutball as well. My kid flies a nutball that has a carbon fiber rod arc in front of the prop that allows him to bounce the plane off everything without a scratch.

Thanks for the info, guys. I should have been a bit more clear, my son won't be flying them, he's still learning to fly his Vapour, but he's keen to come out to indoor flying with me, which means I'm "allowed" to go at nights when the venue is open, hence my renewed interest.

I thought I'd read a bunch of threads about vacforming Depron models, for sure I've seen Harpeye's awesome threads about press forming. I was thinking of trying vacforming but thinking about it, press forming looks a little more controlled. I have some special glass with a conductive coating on one side, capable of up to 350degC, (not that I need to get that hot) with totally uniform temperature over the surface. I was going to sandwich the Depron between two layers to heat it then drop it onto the mould and press it in. The heated glass is actually one of my inventions, I'm developing a transparent toaster with it, it's the perfect solution for this type of thing as the temp control is +-1degC with no overshoot and it will heat the entire surface of the Depron perfectly, so I can get very consistent results.

Stu.

Wow stu, that sounds amazingly cool! Then you could see when your toast is just how you like it

I wish you the best with your venture!

Check out Don Slusarczyk's 36" span, 20 gram "Gronk". It would be challenging accomplishing that with vac-formed Depron.

http://www.rcgroups.com/forums/showt...ighlight=gronk

Originally Posted by Trisquire

Check out Don Don Slusarczyk's 36" span, 20 gram "Gronk". It would be challenging accomplishing that with vac-formed Depron.

http://www.rcgroups.com/forums/showt...ighlight=gronk

I am not sure what your point is. There mat be a lot of planes that may be difficult for molded depron. Then there will be many that are suitable.

Okay. I'll repeat myself. Don Slusarczyk's 36" span "Gronk" weighs 20 grams. Get the point?

I feel like I'm pretty good with balsa, but 20 grams (with electronics) with a 36" wingspan? That's incredible.

contest balsa. crumbly stuff. hard to find unless bought local. its amazing, and amazingly freagile.

Originally Posted by Trisquire

Okay. I'll repeat myself. Don Slusarczyk's 36" span "Gronk" weighs 20 grams. Get the point?

How about molding one of Spence Lisenby's Kinetic 100's in Depron. You could make a slow flying indoor version of the fastest glider in the world.

Same point!

No need to stick to suitable planes. How about a molded carbon fiber microfilm job so you can fly it outdoors in the wind? Of course you would have to double up on the rubber. Or maybe triple it?

Pete

Originally Posted by stumax

Thanks for the info, guys. I should have been a bit more clear, my son won't be flying them, he's still learning to fly his Vapour, but he's keen to come out to indoor flying with me, which means I'm "allowed" to go at nights when the venue is open, hence my renewed interest.

I thought I'd read a bunch of threads about vacforming Depron models, for sure I've seen Harpeye's awesome threads about press forming. I was thinking of trying vacforming but thinking about it, press forming looks a little more controlled. I have some special glass with a conductive coating on one side, capable of up to 350degC, (not that I need to get that hot) with totally uniform temperature over the surface. I was going to sandwich the Depron between two layers to heat it then drop it onto the mould and press it in. The heated glass is actually one of my inventions, I'm developing a transparent toaster with it, it's the perfect solution for this type of thing as the temp control is +-1degC with no overshoot and it will heat the entire surface of the Depron perfectly, so I can get very consistent results.

Stu.

You'd probably have to heat the mould too so you can avoid the problem of the Depron cooling too much in transit.

Same problem in gluing certain woods with hide glue in musical instrument making. The glue will gel when it hits cold wood so you have to pre heat the wood.

Don't ask why hide glue, the answer is too long.

Pete

Originally Posted by derk

Wow stu, that sounds amazingly cool! Then you could see when your toast is just how you like it

I wish you the best with your venture!

Thanks! Yep, it's pretty cool, makes the best toast ever, too, as it traps the moisture inside the bread, making the outside crispy and the inside hot and doughy, so the toast also stays hot a lot longer. It can also lay flat and contact grill a steak in 2 minutes from pressing "go", using a fraction of the energy of any other method, or toast foccacias and let you see when they're toasted. Sorry for the sales pitch, it's an invention which should change the way we all cook but even with live demos to major appliance manufacturers which totally blows them away, do you think I can find one brave enough to want to take it on? The fact that I still make EDF systems tells all unfortunately......

Stu.