A Cardboard RC plane.

[Simon Chaddock]

My plan is to build a card & /Depron wing 40" by 7" so it can be used on my modified Wing Dragon which already has a 'built up' balsa/Depron/balsa wing of exactly this size so it will provide a direct weight/strength comparison.

As construction is limited by the size of the cereal box the wing will be built in four 10" sections. The wing section is a standard Clark Y of 11.7%.

The rib lay out is drawn directly on the lower cardboard skin and the Depron ribs and shear webs simply glued on to it.

The aileron is cut out of the wing. It will be top tape hinged.

A 3/7 g servo added and the aileron skinned.

The whole plane will look like that so I don't think you will miss it!

[Rick Tee]

Love it.

[Simon Chaddock]

The inner wing panel has much more support for the skin towards the root with closer set ribs and shear webs.

Hopefully the extra support will enable the card skin to take higher compression forces before it buckles. In addition this wing will be held down with rubber bands so the skin at the root has to withstand additional external compression as well.

With the two panels covered and joined they can be compared to the existing identical wing made using the same green foam with modest balsa reinforcement.

The card wing feels about as rigid but then it is 54% heavier! To carry the extra weight it will obviously have to fly a bit faster but with a slightly thinner section it should have less drag.

Now I just have to eat some more cereal in order to complete the rest of the wing!

[Mark Kettle 1]

Looks good Simon.

[Mark Kettle 1]

Simon I've been using double skinned cardboard for the wings. 

Will some of these techniques.

Flying here over the sea which we try to keep it out of. 

Edited By Mark Kettle 1 on 18/12/2016 07:10:24

Edited By Mark Kettle 1 on 18/12/2016 07:12:03

[Simon Chaddock]

Mark

That wing looks interesting although it still falls into the 'card + wood' category.

My aim was to build 'card + Depron' where the Depron itself adds little to the overall bending or torsion resistance.

To be honest I am not expecting that card will provide any real structural benefit (more likely a significant disadvantage!) but simply to see the result.

[Rick Tee]

This is probably worth a look if you haven't seen it before: **LINK**

[Simon Chaddock]

Rick

I had not seen that. It certainly looks like a really good effort and obviously the fuselage at least seems to be of a 'card only' construction.

Edited By Simon Chaddock on 22/12/2016 14:11:43

[Mark Kettle 1]

Also Simon and others following, this is also worth looking at, many moons ago I had the CEO of the Smurfit Kappa Group ( Europe's leading corrugated cardboard and the worlds leading paper based packaging company ) in the car on his way to a London Heathrow.

On the journey he shared with me about one of his resent employee's, a designer who came over from Formula 1 too work with them on complicated cardboard designs. Upon starting and after the designer had a look around he had took in the vast range of paper types and cardboard strengths etc, so he said "for PR purpose we can make a man carrying aircraft if you wish", he was given the go ahead and the next video shows the results.

Smurfit Kappa

and this ...ideal for flying events.

 

 

Edited By Mark Kettle 1 on 22/12/2016 16:29:17

Edited By Mark Kettle 1 on 22/12/2016 16:32:37

[Simon Chaddock]

The completed 'cereal box' wing with an all Depron equivalent..

Both are 40" span and 7.5" chord. The all Depron wing weighs 105 g whereas the card/Depron one comes it at 165 g or 57% more but it plenty strong enough for mild aerobatics.

Had its maiden this morning in calm but cold conditions.

The frosty grass was super slippery making belly take offs easy.

[Mark Kettle 1]

Nice flight Simon, have you weather proofed the cardboard surface?

[Robin Colbourne]

KC mentioned the Pappendeckel by Mike Smart. Thanks to some kind Swedes who uploaded it, it is available here: **LINK**

Note the clever use of the bottom of a Comfort fabric conditioner bottle as a cowling!

 

Edited By Robin Colbourne on 01/01/2017 22:55:29

Edited By Robin Colbourne on 01/01/2017 22:57:05

[Simon Chaddock]

Mark

No it relies on the glossy(ish) printed surface and the rather sense cardboard for protection. It would seem to be adequate but of course would not stand much real rain.

[Graham Stanley 3]

Re Stanley Model Aircraft.... Sorry to say only I am left, Frank (my dad) passed away several years ago.

Between us we designed the Apprentice 60" as a low cost replacement for the "Slim Jim" trainers I was using to teach dad to fly with. It turned out to be a strong model with good flying qualities. We did try a full cardboardboard wing on the early prototypes, but ended up with a foam leading edge to achieve good handling. Early "purist" prototypes had no spars in the wing, but 6mm x 6mm spruce was added very early on after a wing fold at a Sywell public show! We had some great support from the press, and David Boddington was especially supportive..

The Craftsman 60" followed on, styled on the 1930 style races, later versions having a vac formed cowl.

Sadly we didn't market it widely enough to support the volumes needed for the cardboard manufacturing process, batch sizes in the 1,000s being needed. The cardboard was made specially for us, with smooth (craft) paper both sides.

The USAF club based at Upper Heyford mandated the Apprentice as their beginners model. I remember Major Hanover ordering a lower rank to buy one at a show!

[Andy C]

Well, look what I now have. Think it could be complete but don't have any instructions or plans which is a shame as would love to have built it. I'm still hoping they turn up in previous owner's loft though.

[Graham Stanley 3]

I can dig out a copy of the instructions for you. That is a Craftsman 60 Mk2, which has veneered leading edge D section and Spruce spars. You will need PVA glue, Solarfilm or equivalent heat shrink glossy film covering and metric ruler. All the (card) parts are identified by their length in millimetres.

I will try and remember which moulded cowls fit it too. Power can be anything between a four stroke 40 (scale like flying), two stroke 40 for normal sport flying, upwards. One customer fitted a 90 four stroke, but the model is designed to balance correctly with a 40 two stroke.

It may take me a while to dig them out, please send me your email so I can forward copies.

Graham Stanley

[Graham Stanley 3]

Instructions for the Craftsman can be seen here -

https://docs.google.com/document/d/1zeryw3Xjkx-8wQ1T6N-T8POlZLnuUpIW4rVVWIdh6N8/edit?usp=sharing

[Alan Gorham_]

Or here if you don't want to cut and paste:

**LINK**

[Nigel R]

interesting stuff graham

a true ancestor of the fanfold type foam board models that are around in abundance these days,

I see a few other things - like the depron wings made from a single sheet scored and bent around a depron spar, which strongly resembles your methods (rear of wing, tailplane).

what sort of all up weight did the craftsman come in at?

[ChrisB]

A good mate of mine, now sadly departed, Dave Orton used to fly a cardboard plane from Lawford Heath and then Rolls Royce Ansty.

I think that was a Craftsman. It must have been back in the 90's when he flew it. From memory it had a Laser 70 up front.

[Graham Stanley 3]

Sorry I can’t remember the all up weight. 6 lb rings a bell, but that sounds a lot for an aircraft with such a good low speed flight capability.

We did fit anApprentice with a 20 size four stroke. It was exceedingly economical, but very marginal on take off. I recall it flying for an hour on 6ounces of fuel.

[Dave Cooper 3]

I use card a lot mainly for making 'template' structures out of other materials - old birthday, anniversary cards etc are great for this as you get a wide variety of strengths, weights and thicknesses. However, for primary structure on models I think it needs the following :-

1. Extra support in key load-bearing areas eg wing 'D-box' structures, fuselage former and stringer coverings.

2. It needs some form of water-proofing - even a slope soarer will get put down on wet grass occasionally.

3. IC power models need careful fuel proofing from the inside out - not easy in difficult to access areas, but, fuel will probably find a way in.

4. For longevity, the card will probably need to be quite thick if you want to avoid a lot of time on repairs /maintenance - need to watch the weight when it is 'distant' from the CG.

5. May need surface sealing before adding paint etc.

Depron

1, 2 and 3 above apply depending on the adhesives / joining methods used.

Correx

My "Wildthing" (largely EPP) had a Correx fin and elevons as built from the kit. After about 5 seasons the Correx began crumbling away even though it was stored out of direct sunlight when not in use.

I could have just replaced same with more Correx, but, it now has a balsa /ply /carbon fin and elevons....there's a moral there somewhere !

Dave

[Graham Stanley 3]

Hi Dave. I agree with your comments. On the Craftsman instructions (link above) there are a number of illustrations showing exactly how we added local bits of spruce and ply where needed.

[Graham Stanley 3]

We also added veneer to the leading edge D foam, not for structural strength but for cosmetics and to make it easier to cover. Solarfilm was best, the extra weight of Solartex wasn’t worth it. I thought the Solartex versions didn’t fly as well. Weight of surface finish?

[Dave Cooper 3]

Hi Graham - I'd heard that Solarfilm and Solartex was no longer available ? However, on researching other coverings for my next models I found a reference to 10 Micron Melinex (film) covered with 'Jap' tissue which they say is light and very durable /takes paint etc. (ref: George Stringwell's "Radio Controlled Gliders". I think this will also be suitable for small, light card models.

For the larger, heavier models, Ceconite is also worth considering but you need to search for the very lightest cloth. We use this on full-size gliders !

I believe prices for the above are very reasonable but may require a bit of hunting down...

Dave