Humbrol Tiger Moth

[Andrew D]

Why on Earth would the government limit the suction of a vacuum cleaner?  Thats bizarre.

Was the EU, with the aim or reducing power consumption.  It's a pain in the UK, as we have a habit of having more wall to wall carpeting that require a bit more ooomph than on the continent where tend to go with hard floors more...

[Piecost]

Thanks for the information about your vacuum setup Andrew.

Tim

[Piecost]

This post feels like a confession of a dirty secret. I have only once before resorted to using DIY filler on a model and never on a wing.

I have been having an awfully tedious time sanding the wings.

I put some effort into pre-sanding the leading and trailing edges and checking their profiles against the ribs, before assembly. But still found problems.

I cut out a card profile board as a reference. This is rather overkill and I certainly am not concerned about accurately reproducing whatever wing section the kit specified. But, the photo below shows how the profile.board helped to highlight the step between the rib and the leading edge.



I ended up adding shims of balsa:


And in particularly bad areas I applied DIY store lightweight filler (shown before sanding)


At least the trailing edge matched well to the sanded rib profile.

[Piecost]

I have glued the wings together with balsa cement (thinned Duco). The root ribs were precoated a couple of times before the final application.

This should allow me to seperate them, with acetone, if a repair or replacement is needed. The 19mm tip dihedral specified in the plan corresponded exactly to the width of Lego bricks. I used tape under the joints and small baggies of lead shot to hold the wing panels down without warps.

Final shaping of the centre section will follow; so that the structure matches each panel

[Piecost]

The fuselage has glued together not straight. This is disapointing; considering the tab and slot construction. The sides were of similar stiffness, so that was not the cause. I have to live with it or scrap the fuselage. I chose the former.

At least I can try to get the motor thrustline, wings and tail in their correct orientations to each other.

I layed the fuselage on foamboard and marked the centreline as best I could. The centre of the nose was not near to the pencil mark. Oh well!

I marked 2 degrees sidethrust bisecting the centreline and used a card shape attached to the engine firewall to eyeball thenalignment.

I used a card jig resting on the fuselage botttom and the back of the firewall to set the downthrust.

[Piecost]

The three canted and uncanted ribs forming the joint between the centre section and each wing panel lack the sharp crease where the dihedral begins.

So, I added tape at this point, as a guide, and made a sanding block to the exact width of the centre section. Unfortunately, more balsa shims and filler was required.

I am disapointed with the amount of rework nessesary to such a simple structure. I hope that this is rewarded with a covering that is smooth and wrinkle free.

[Piecost]

I have installed a refurbished Telco.

I need to check that it runs before gluing the top decking on the nose. Unfortunatley, my large soda stream bottle is empty and I understand that the bottle it uses is superced (I have not flown CO2 for a long time). So, I need to get a friend to fill thw tank to test the motor.

The first photo shows the hole in the bottom of the firewall through which the  cylinder head and pipework are threaded before attaching to the cylinder head.


The send photo shows the inclinded tank installation. The filler nozzle will protrude out of the front cockpit.

[billdennis747]

Where I am, Lakeland stocks both types of bottle.

[Squirrelnet]

Unfortunatley, my large soda stream bottle is empty and I understand that the bottle it uses is superced (I have not flown CO2 for a long time). So, I need to get a friend to fill thw tank to test the motor.

I use Grabner refils in Abergavenny they can fill all types of bottles including the ones with the old thread for about £12 + post

[Piecost]

Thanks for the recommendations gents. I am very happy to not have to change my charger.

Squirrelnet; I have been reading your helpful vacuum forming article from the August 2021 Aeromodeller.

My fuselage has not turned out exactly the shape as the plan intended, so I have to make a new rear decking mould. I will use balsa, rather than MDF, this time. Since it is easier to work.

[Piecost]

The cowl was formed from the 0.5mm yellow plasticard. I cyano'd a couple of rings of the same plastic to reinforce the hole for the propeller. A Sharpy marker made a convenient mandrel tonline them up.

I intend for the hex throttle nut of the Telco motor to protrude from the cowl.