Depron Heinkel HE162

Spent a bit of time testing printed rib construction as I not sure that the structure I am using so far for the ribs is as light as it could be.
So two identical ribs of the same 3 mm thickness.

The upper rib uses the form I have used on the majority of previous printed rib Depron covered wings. A lattice with a thin (0.2 mm) all over membrane. Only the rib outer profile is specified as the bracing and the membrane are 'print' features in CURA.
The lower rib uses a structure where the position of each U channel member is mathematically specified. Takes much longer to programme and to print but it does retains the geometry when it is scaled up or down.
To my surprise although the top rib looks & feels lighter it weighs 1.593 g.

The bottom rib is only 1.370 g, nearly 25% lighter. :ohmy:

I appreciate the difference is only a fraction of a gram but in this case a saving of 25% on the total weight of all the ribs will be worth the effort and the more than doubled printing time!
Enough 'playing', back to planking.

The first two bits together but just stacked one on top of the other to get an idea of how they fit.

The wing root is not quite as wide as the slot but is it still pretty wide!
The cockpit will be huge.

It would be possible to put in a fully detailed cockpit as the battery will easily fit under the seat or even in the nose cone if required.
The exhaust over the fuselage.

The exact detail will only be added when the rear fuselage is in place.
Not shown in the picture but there as still a few fuselage planks still to go on but so far so good. .

Seemed to have spent most of the day repairing the leg mounting on my daughter oak, and expensive, dining table.
Each leg is held by two 8 mm bolts into threaded inserts and sods law it was the inserts threads that had stripped! Not that surprising as the bolts supplied only reach down about three threads. Ditched the bolts, cleaned up the insert thread and extended the hole 30 mm into the wood (and threaded that too( and screwed in a piece of 8 mm screwed rod. The screwed rod is permanent as the leg is now retained by a nut.

Anyway I eventually managed to print out the wing plan to the correct scale.

It does rather show how broad and short the HE 162 wing is.
The fuselage wing saddle will have to be 'adjusted' slightly to match the wing rib underside profile. As the wing will ultimately be just glued on it needs to be a good 'all over' fit.

The wing is going to put a serious dent in my supply of 2 mm Depron!
Anyway after much thought I took the plunge and cut out a wing skin.
I will get 2 skins out of a full sheet and of course will need 4 in total. :woohoo:
It seemed sensible to test the build sequence before cutting out all of the skins.
The printed ribs and the "inserted" hard balsa spar in the lower wing skin.

If you look closely there is even the bit of Depron cut out lying on top.
The tapered spar only goes out 2/3 of the span as the Depron alone should? be quite adequate for the outer 1/3.
The "Lippisch Ears" (the downturned tips) will be added once the wing is complete.

looking good Simon, never appreciated that the wing was so broad.

I thought the Germans favoured broad wings as a lot of their aircraft had them

Is suspect in this case the broad, highly tapered wing was chosen because they were made of wood.
Such a wing shape gives a good root thickness even when using a relatively thin wing section an important attribute given woods limited strength compared to aluminium.
The DH Mosquito actually has a similar wing planform for much the same reason. The rather more extreme shape chosen by Heinkel probably took into account the state of German manufacturing by late 1944.

It is perhaps worth noting that even DH had to adopt Dural flanges screwed & bonded to the wood spar for the DH Vampire which was actually designed 2 years before the HE 162.

I know LiPo have to be well packed but.........:woohoo:

The 450 mAh 4s for the HE162 from the HK warehouse in Belgium.

I have been trying to get a lipo for the micro helo and been told they cannot be sent via RM ?

These were sent from Belgium via courier not RM ?

Rich
Yes, they were delivered here by Hermes from HK Essen but it was actually ordered from HK Hong Kong.
As we are no longer in the EU there is a customs declaration as "Hobby Parts" but I note with amusement the gross package weight is given as 0.0001 kg or 0.1g!

A start on the RH wing.

Ribs glued onto the lower skin and the Depron shear web added between them.
The leading skin including the upper balsa spar will only be added as far back as the shear web. The resulting box spar will make the wing rigid enough to be completed 'free hand'.

nice job!!

Quite a bit done today. There are now 3 big bits.

As the wing is easy to damage in this state I think I will add the aileron servos so the wing skin can be completed.
Then it will be on to the rear fuselage (more planking) and ultimately the tail feathers. With those done the wing can be lined up to match. If the wings and tail 'out of kilter' it is very obvious.
The big concern is the weight. The thee bits so far weigh 300g which means even 500 g will be a hard target to achieve so it looks like a total of 18 oz rather than 16 let alone 14. :woohoo:

Just caught up to where you're at with the build, very impressive ! Time for one of my probably dumb questions. I think you are using a 50mm EDF ? On completion, If you require more power, would there be room for a 64mm EDF mounted slightly further forward in the nacelle?

crash
Actually it is using a 'racing drone' 68 mm 4 blade prop and motor on 4s so if all else fails I could use a 70 mm EDF but it would of course be a great deal heavier and require a bigger (5 times size) battery!
At the moment it is using the same motor/prop set up as I used in the nacelles of my Airbus A350 which flies well enough however in the HE 162 the duct is 4 times longer so will cost a bit of thrust.

At the moment I will continue with the 'light as possible' approach but if it looks like the thrust really feels too feeble I could go up to a 6s, as used in some racing drones, but the motors are not really rated for continuous running at such power and are likely to overheat.

This my 'You have got to be joking!' picture.

The intended 4s, and yes it is the flight battery, shown against the back wall of the cockpit. :woohoo:

The electronics bits should fit, then! [badass]

Does not look much but there was quite a bit of finishing and sanding before the aileron servos could be fitted.

Every time I wire up 3.7g servos and solder extensions in 32 AWG wire I say "this is the last time" but it seems it never is. :ohmy:
The top skin can now go which will complete the basic structure although it will take about 1/2 a tube of POR to do it.