Depron Heinkel HE162

I know it does not look like much but I have at last (about 20 hours work!) finished the drawing.

The next problem is not the fuselage, the formers sizes will generate the required fuselage, but the tail plane and fins will have to be individually redrawn to the correct projected size. I'll worry about doing that when I built the fuselage.

Clear the table top to start on the fuselage. It will likely be in 3 sections. the centre part first so it can be matched up to the nacelle.

It would be so much simpler, and probably cheaper, to just go an buy an ARTF!

I'm sure a tutorial on what resources and software and how you use it to design your models would be a welcome article Simon?

I agree Simon! it would be easier to buy a artf but there's no fun in that ( imho) why would you want a poorly built piece of Chinese crap when you can create something wonderful with your own hands?
lovely drawing.

Made a modest start to cutting out the first 3 formers for the centre section.

Former F is the rear of the cockpit. The circular holes are nothing to do with the EDF but simply to make it easier to get things down the fuselage and to save a smidgen of weight.
Just to give an idea of size at former F the fuselage will be 8 ¹/₂" tall and 7" wide.
There are 21 formers in total.

Just plucking a number of the air but considering the full size was fairly small yours must be around 1/6 scale?

From my drawing the wing span will be 1384 mm. The full size had a span of 7.2 m which give a scale of 5.2:1.
This does sound like a huge plane for a 90W EDF. Although size itself is not a problem weight or rather wing loading is and at the moment I don't have a good handle on how heavy it might be.
Despite Depron being very light there will be a lot of it so unusually the basic airframe will make up a significant proportion of the total weight.
At this stage I can only guess it will be close to 16 oz all up thus giving 90W/lb which should at least be flyable. If I have done the sums right it will have a wing loading of 3.6 oz/sqft which is an extraordinary figure for an RC plane, let alone an EDF.

Spent quite a bit of today tracing and cutting formers, all twenty of them, but that is still less than half the total!

They will make the fuselage centre section.
It will also need 'disposable' top and bottom keels to be fixed onto the plan so the formers can be glued to them and likely with disposable jury struts too. At least the change in cross section over this bit of the fuselage is not too great so the individual planks will require only modest shaping.

Once the centre fuselage is complete I will have a better idea of the likely all up weight as it represent the biggest use of Depron, Hopefully it will indicate the AUW to be closer to 400 g (14 oz) than 500 (16 oz)!

Nice neat work! I like it.

The planking begins.

I must say it is nice to actually make something rather than doing the rather tedious preparation.
Of course even when this bit of planking is complete there will be another 5 lots to do and that's just for the fuselage.

Once the centre fuselage is complete I think I will need to build the wing as its upper surface fairing plays a vital part in how the nacelle will be mounted even if it is not actually fixed on at this stage. Anyway making the wing with printed ribs? will give me a break from planking.

The first half shell complete.

The row of pins indicate the position of the last plank.
It is actually lifted from the plan but is resting lightly weighted whilst the glue hardens.
The next bit is actually the most critical as it is very floppy and liable to build in a twist twist until a proportion of the planks are added to the other side.
The printed centre rib.

It is printed in two parts either side of the spar line. A rather complex mix of variable depth beams and a lattice framework.
I shall have to find out how well it scales otherwise I will simply use hand cut Depron ribs.

With the other half of the formers glued in place it becomes a bit of an essay in "wobbliness" or rather how to control it with jury struts.

It will all get much stiffer after the first few planks go on. The trick is to make those quite narrow so it puts the minimum strain on the structure.
I will just have to remember to take out all the struts before the planking goes to far.

As it is only printing time the full set of ribs for one wing set approximately in their correct position.

The HE 162 has a rather highly tapered wing which when coupled with Heinkel's penchant for a straight leading edge gives a notably swept forward spar line. Not ideal for a flimsy light weight!

We shall see.

Use a carbon or spruce spar and a hard balsa leading edge.. looking good

Carbon or hardwood spar?
I don't think such will be necessary as I believe (hope!) the Depron skin will resist the forward sweep torsion forces adequately.
My plan is to include a 2mm tapered balsa spar 'flange' within the top and bottom Depron skin. There will be a Depron shear web between them.
Somewhat along these lines.

To keep weight to a minimum, it will be quite a big plane for the power available, everything has to be 'just strong enough and no more'.