A light weight Gloster Meteor

On the RCME site I have been in discussion with a feather weight (sub 100g!) flyer who wants to build a Gloster Meteor.using two brushed 30mm EDFs. They are very light and with just 50g thrust at best! 
My suggestions have centered around using 2mm Depron "planked" structures.but foam sheet planking is not popular and certainly not in the feather weight class.
Anyway the concept is interesting and in true scale which the feather weights rarely are.
First there is the subject of the Meteor "fat" nacelles resulting from the centrifugal compressor Ghost turbojets and the equally minute inlet and exhaust areas.
 
Not good for an EDF!
Being realistic it seemed logical to keep the inlet to suit the 30 mm EDF but increase the exhaust to match the EDF. Some thing along these lines.
 
Even so it would still be a fat nacelle.
I can get 2mm Depron but a suitable box of sheets costs nearly as much as much as a full kg reel of E Sun LW-PLA!
Just for fun I used Free CAD to see what might be possible.
 
The advantage is it is quite easy to incorporate the necessary features to install the EDF inside at the front.
 
The duct also tapers from 30mm diam at the EDF to 28mm at the tail pipe.
Printed in LW-PLA it would weigh about 17g.
I expect using a 2mm Depron outer skin around a printed LW-PLA duct would be a bit lighter and be much tougher but it would also much extra work. So much easier to print the whole nacelle!
Its not even that I intend to actually buid a feather weight Meteor.     
 
 .   

After some reflection I decided to buy a 30mm brushed EDF. I suspect the same thing as in Eric's lightweight off the shelf job.
The main reason was to see how much a meteor style nacelle might weight using my preferred LW-PLA  printed duct and 2mm Depron planked outer skin.
This progress so far.
 
The EDF weighs 9.8g and the LW-PLA duct just 2.1g
Now to add some circular formers to give the planked skin the profile of a Meteor nacelle.    

The LW-PLA duct planked in 2mm Depron, there are 22 of them, each individually shaped. Then a light coat of silver paint.
 
 
The EDF weighs 9.8g. The complete duct is 18g. It delivers just on 30g thrust on a 1s.
A 3 view of a Meteor F3 but with the EDF nacelles superimposed.
 
It would have a span of 20"
The nacelle is scale length, max diameter and inlet but with an over size exhaust to suit the EDF.
Still not sure I actually want to built it. 
  
  

The planked nacelle although strong is very tedious to do so I tried a Mk II.
Instead of "planking" the inner duct and the 3 formers with Depron I "sheathed" it with a LW-PLA single wall 'vase' printed skin in two parts joined over the largest former.
 
Done this way does give the nacelle a nice smooth profile and is much quicker to do particularly if you have more than one! The downside is the formers have to be the exactly the right diameter to snugly fit in the skin so they can be glued to the skin. To my relief the printed skin added less than 1g to the total weight of the nacelle compared to the Depron planked version.
I did try printing a complete 'one piece' nacelle but it ended up considerably heavier to achieve the same surface quality as just vase printing just the skins.

Now I've got two nacelles I suppose I will have to build the rest of the Meteor!   
 
 
 

First the wing centre section. 2mm foam sheet top and bottom with 5 LW-PLA ribs.
The centre rib. It is a scale symmetrical 12% section. As it is the biggest it is also the master. The other pairs will be scaled in CURA.
 
The end of the wing will be sanded to exactly fit the nacelle and then simply glued on directly to give the lightest possible joint.
 
As there is no spar the wing skin carries all the loads so a direct glue joint will simply transfer the loads directly onto the nacelle skin. Well that's the theory.
The two nacelles and the wing centre section weigh a total of 40g.
The weight is creeping up fast!

 

I am waiting delivery a second 2g servo for the other aileron to complete the RH outer wing panel. 
In the meantime I made a start on the fuselage.
A big advantage is the Meteor has long flat side panels which means it can be constructed in a very conventional manner.
Just resting, not yet glued on to the wing but it does show the cumulative progress so far.
 
All in "real" 2mm Depron. Unfortunately my existing supplier of 2mm has disappeared off the web so I may not be able to get any more. 
.

Planking that relatively tiny fuselage has proved to be a bit of a nightmare but I persevered.
Just resting on the wing.
 
The nose cone is printed single wall in LW-PLA.
Note the plethora of tiny masking tape strips to hold each plank in place until the glue sets.
In the state it is in the picture it weighs 6.2g, which is not too bad.
It will need a bit of sanding and filling.
Still waiting for two more 2.5g servos and the lightweight brushed ESC.    

Eric
Yes I have but at the bottom line I am trying to use components that are not specialist to an indoor lightweight but that could be used in a more conventional outdoor plane as well.

The beginnings of the fin and tail plane added to the fuselage.
 
All single sheet 2 or 3mm Depron except the fin onto the fuselage which is a true aerodynamic section to both support the high mounted tail plane and to create a structure to hold the 2g elevator servo. Although this will allow a simple direct link to the elevator horn it is a concern to have a servo so far back but I trust the weight of the LiPo will to compensate for it.
The tail plane does have some hard balsa reinforcement. The two halves of the elevator are joined by a 2mm carbon rod.
 
In the above state the complete fuselage now weighs 10g exactly. 
This will be a bank and yank EDF so there is no rudder. 

I can remember when the Meteor first came out, my dad and i went to a display at RAF Cranwell a few miles from Ancaster where we lived and  a Meteor was standing there and then put on a display, hell of a site and sound in those days, a long long time ago 

As a 5 year old we lived in Sevenoaks not far from Biggin Hill which then was an operational RAF base. Both Meteors and Vampires were regular over flyers. Meteors were noisy whereas the Vampires just went "wheee".
As a result all jets were called "whee" by me except helicopters which I very logically named "whicker whee" from the rotor noise they made. 

The latest picture of the Meteor. 
 
Structurally almost complete with just the canopy (battery hatch?) still to do.
I am still waiting for the 2g elevator servo, the ESC and the Rx before the wing is permanently fixed.. I am assured by email they are now in the UK and are "out for delivery"
What's in the picture weighs 67.3g.  

Believe it or not this is a 10A ESC for 1S!
 
It is double sided. This side has connections for the +/-  & PWM. The other side has connections to the motor.
At 10A it should be able to power both the brushed EDFs on the Meteor and it obviously doesn't weigh much at all.
By far the biggest problem will be soldering on the wires. 

I also have its 4ch Rx which by comparison seems enormous even at 1.7g!