RC Hawker Hurricane built with a Hot Wire CNC foam cutter

posted in: Radio Controlled | 0

 

Why build a Hawker Hurricane in foam with a Hot wire CNC foam cutter? Well as you may have noticed on my website I’ve built a Hot Wire CNC foam cutter and built a several flying wings. So I was thinking about my next build and it had to be the Hurricane IID tank buster in Desert Air Force colours. I already have a Spitfire and Lancaster and had just recently read Leo Mckinstry’s excellent book on the Hurricane which inspired me to make it

Huuricane IID
Finished at Last

 

Building a model from scratch is quite challenging and requires a lot of research but I enjoy that and you sort of build an affinity with the aircraft.  So that keeps me going when sometimes the motivation slides a little.

Do you need a Hot Wire CNC foam cutter

The short answer is No. You can make foam core wings and fuselage sections without a CNC machine and many model builders do. I did before I built my CNC foam cutter machine for my Super VC10 but only for the wings and tailplane. I used a gravity hot wire bow which pulls a hot wire over some airfoil templates. Works quite well with a bit of practise but making the templates takes a lot of time and you usually need one for the top and bottom of the airfoil which soon adds up. It could be argued that the time I’ve spent on the CNC machine is far more and that’s probably true. But now I can produce a wing in one cut and in about 20 mins. My third flying wing was a quick build after I crashed the first one through pilot error.

A good thread on RC groups on gravity hot wire foam cutter click

We need a plan

Firstly you need to decide what size aircraft you are going to build. Well I wanted something that was similar size to my Ripmax Spitfire for ease of storage and transportation so I settled on a 50 inch (1270mm) wingspan. There are quite a lot of drawings and CAD plans on the Internet for most airplanes . I always try to find a CAD drawing in DXF format which is an industry standard which you can use one of the Free CAD programs to scale the drawing to your dimension. My favourite is DraftSight

The Wings

I’ve used two pieces of software to generate the g-code to build the Hurricane. The wing g-code is developed in Profili2 Pro and fuselage in DevFus Foam. See my article Free CNC software if you are on a budget.

Profili2 Pro is quite an extensive program and has evolved over the years and can do lots of other clever stuff with airfoils. It has an option to generate g-code for 4 axis CNC machines and this is what I used for my flying wings. This has now been upgrade to DevWing Foam

Part 1 in the video list below show how the wings were made with Profili2 Pro, but you could of used on of the free options I’ve linked above

The Fuselage

I used DevFus Foam will generate the g-code to produce the fuselage sections. Which is available in Demo version that are fully working apart from being able to save the g-code. www.devcad.com

Part 2 in video list shows how to use DevFus Foam to make the fuselage

Part 3 in the list shows and the build progress

I’ve now created a video series on how to use DevFus Foam 2  to build the fuselage of a  BAE Hawk with a electirc ducted fan.  Here’s a link to it http://www.rckeith.co.uk/getting-started-devfus-foam-2/ At the time of this update the Hurricane is finished just waiting for its maiden flight.

 

 

 

 

Maiden Flight

On the 7th of October she was ready for her maiden flight.  I was quite nervous but reasonably confident she would fly well.  I’d worked out with a 3000mAH 3S Lipo battery I would have 5 minutes at full power, but you don’t fly on full power all the time so I set 5 minutes on the timer.  She was hand lauched, the undercarriage in the pictures is just for static display and is taken off for flight.

She leapt away and was a little lively until I got her trimmed and on lower rates, but she flies very well, what a relief after 3 years since starting this project.

 

0 Responses

  1. Keith Renecle

    Hi Keith, thanks for all of the great info on the cnc foam cutter. I want to build a similar machine so this info really helps for me to know what to buy and also how to use it all. Just a few questions on the Hurricane build. What type of glue do you use to join it all together? It is obviously something that sands well. Finally, do you cover the entire model with anything like glass cloth or tissue before painting, and if you paint the raw foam, then what kind of paint do you use? Thanks again!
    Regards,
    Keith Renecle
    Darkest Africa

    • Keith

      Hi Keith
      I use expoxy to glue it all together and because it takes a lot I just get from our Pound shops in the UK.
      On the wing I’ve just used brown paper and PVA glue to cover but on the fuselage I have some Poly C and cloth from here http://www.rcworld.co.uk/acatalog/Poly-C-500ml-PolyC500.html but havent used it yet.
      For painting I then to use emulsion match/tester pots from the local hardware store and spray on with a small air brush. Usually they can match a colour form a book, get some strange looks when I take my wardbird books in. I then use water based gloss varnish to seal and because the tester pots are matt it give a satin finish that’s easy to keep the dust off. I have on some models just painted on the foam and I always use emulsion for that.
      I still haven’t finished the Hurricane but I’m retiring at the end of the year so hope to get it finished then or maybe before with lots of other project and a few repairs.
      Hope that helps, and any question ‘ll be glad to answer
      Where in Africa are you ? I lived in Zambia for 2 years when I was a kid
      Keith

  2. Keith Renecle

    Hi Keith,
    Thanks for the info. I would have thought that epoxy would be hard to sand next to the foam. That brown paper is also used on foam slope soarers but I find it to be rather heavy. I have a roll of teabag tissue and it is almost identical to medium weight silkspan, With the thinned white wood glue this makes a really good covering over foam.

    I live in Centurion near Pretoria. Zambia was most likely more livable when you were a kid! It’s still not as ruined as Zimbabwe.
    Keith R

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