Mode Zero

Having accumulated a couple of spare Merco 61s as part of the Concord build, I was looking for a model that suited these and as Lockdown looks like it is here a while longer, well Belair and SLEC are local to me, so a plan was hatched and after the Belair Laser parts kit http://belairdigital.co.uk/detail.asp?id=1201 arrived on Thursday by DPD within a week or so of ordering. A quick call to the guys at SLEC and Friday saw all the "stuff" needed to get cracking arrive and was only delayed a couple of days whilst I finished the Mini Drake off and hung in the rafters of Swaffham Skunk Works awaiting a suitable opportunity to test fly.
So the workbenches were cleared this morning and work started.

Despite the long tail moment, I weighed a couple of HS85MGs and they were lighter than the dowel pushrods I would have otherwise used, so mounts in the rear fuselage were made, the fuselage is now in the jig clamped up overnight and settling down in it's square position before further gluing takes place.


Here are some pics from this afternoon's activities in the Skunk Works

Reasonable progress made today, made up a nose gear, checked that the tail servos would fit the holes and got the fuselage fully aligned in the jig and all glued up.
Also made a start on the wing panels so no major hiccups to report and all going to plan.

This afternoon's work included finishing off the basic wing structure and a rapid dash over to Tesco's model department in Watton to pick up some more 1/8 x 1/4 Spruce for the spars that I had forgotten to order last week. Leon from Belair was also helpful as I was trying to puzzle out the location of some ply sub ribs included in their pack, but not seen anywhere on the plan and these turned out to be doublers for the main gear ribs, which I though was a great idea, so these were duly glued and clamped in place, whilst I was grabbing more spar material from Tescos in Watton!
A start was made on the tail feathers with the internal structure marked out on the 3/32 sheeting which needed joining into a larger than standard width. The marking out was a bit of a faff only because the wing was pinned down to the plan drying and was obscuring one tip of the horizontal stab.
Only work on the fus today was staring at the top and bottom rear sheeting, trying to decide whether to attach it at this point but decided it might be better to leave the top sheeting off until the stab and fin are complete, so I can get good access when attaching and aligning these parts.

Oh I did decide to use a tool that I have had for years and never really used in anger much, that was the Great Planes Dead Center which proved ideal to mark very accurately the bolt holes for the Merco and after drilling through with a 3 mm wood drill, was relieved when the 2 BA bolts dropped straight in and BA blind nuts (that I have also had for years) were fitted to the underside.

Great plane the Moonglow. I did a RCM&E plan feature using one of Leon's kits in Nov 2018. Powered by an Evolution 15 petrol it's a cracking aircraft, good manners and looks great.

Shaun wrote: 26 Jan 2021, 15:06 Great plane the Moonglow. I did a RCM&E plan feature using one of Leon's kits in Nov 2018. Powered by an Evolution 15 petrol it's a cracking aircraft, good manners and looks great.

moonglow - take off.jpg

That looks good Shaun!

I reduced the dihedral to 1 3/4"or 1/2" on the top wing surface.

To get this right, I made up a pair of dihedral boards to join the wings today.
It was a bit of a head scratch as the plans is very unclear as to how you get the two wing halves joined.

Anyway spent most of the afternoon getting the wing join bang on.

Here is how I did it:
1 Set the tip incidence datums. 2 compare the tips to check for any errors, as you can see the basic wing was about 2 mm out at the tip due to a very slight twist in one panel 3 set both panels up on dihedral board and pin down one ( the true one) panel to the board, then adjust the other with weights/packing, so that the tip datums are both at zero incidence. 4 Then the fun starts with cutting centre ribs, chopping the kit supplied hard 1/4 balsa braces and making ply dihedral braces from 1/8 aircraft ply! 5 lots of trial fitting, measuring and adjusting so everything in the centre section will dry assemble correctly. 6 measure again and then get the epoxy out!

I used UHU Endfest 300, this is a 1/3 tonne adhesive, which you can increase the tensile strength even further to about half a tonne by tempering the mix with a heat gun. As I sit here writing this, the smell of hot epoxy is wafting through the workshop as it cooks in its clamped state. If tomorrow, you hear a big thud from the East, then you know, I have cocked it up and I have some more firewood to heat the workshop!!

Off for a beer now and a catch up with Mr Kitchen!

Whilst the wing was still on its dihedral jig, got all the wing hold down plate and spar webbing all completed without major fuss, just loads of time required with measuring and checking everything was square. Got the wings sheeted by joining up enough 1/16 sheets to make a complete wing panel skin and it was then a case of attaching to leading edge with medium cyano and then aliphatic on all the rib tops and spars and rolling it over the wing making sure there was no stress in the skin as that would twist the wing when dry...then out with lots of heavy weights to hold it down whilst it dried.

Also built the tail surfaces and pre hinged them on the building board. I slotted the control surfaces to align with the tailplane and did this by using half thickness trailing edges so it made the hinge lines exactly central.
Much easier than doing it at this point rather than later when the model is covered.
Thought I would check wing and tail alignment and put the model on its wheels for the first time.

Your build is coming along very nicely Stuart.

Looks like you have been putting in a lot of hours to get it this far so quickly.

Should be a great flier when completed.


Mike F

MJF wrote: 29 Jan 2021, 20:38 Your build is coming along very nicely Stuart.

Looks like you have been putting in a lot of hours to get it this far so quickly.

Should be a great flier when completed.


Mike F

Thanks Mike, am lucky in that I have a very understanding and supportive partner! It is the wing that has taken all the time so far, sadly, I havent kept a log of time, but would estimate about 35 hours to date.

These arrived today from Dave at Inwoods, so the HS 225MGs found their new home in the Moonglow wing.
They will look quite convincing as a replacement for the original central servo and bell-crank design and a couple of hours work saw them fitted in place.

Well, pretty much after an elapsed time of 7 days from starting, finally got the wing sheeted today with just some detailed bits n bobs to do, such as adding the tips, cutting out the ailerons to do now before I crack on with fuselage again.

I had been faffing about thinking about the best way to do the aileron structure and decided upon my pre-hinging method I used for the stab would be the way forward.

Before I got stuck into the cutting of the ribs for the internal aileron structure, I thought that I had better have a final check of the wing's trueness, so armed with two mobile phones and the clinometer app on Google play, you can see that I was pretty happy with my tip to tip comparison results! With only an indicated 0.3 degree difference, I was delighted! Whilst I had access to the undersurface, I bored a couple of holes for teh servo cables and fed some string through the wing to pull cables through when it is finished. I adjusted my dihedral boards for anhedral so I could work on the underside without inducing any stress of distortion into the structure.

As with the tail surfaces, I used the pre installed hinge slot method which involved producing two tapering leading edges for the ailerons; where I could adjust the hinge centre line to be in the centre of the wing trailing edge and make the necessary slots and reinforcements for the mylar hinges.
Hopefully you can see from this photo how I did it and this is taken before the lower aileron leading edge is added. Glue is added between the hinge areas to bond the wood together but still allow the hinges to be taken out for re insertion on final assembly. I also need to knock up some aileron horns which took all of 10 minutes from some 1.5 mm Glass fibre board.

Then it was just a final check over that everything was ok and the wing skin panels were pinned and glued to the leading edge with thin cyano, all the internal structure was given a dose of alipahatic after a few dry assenbly runs and adjustments/tweaking to ensure the lower skins had NO stress or distortion in them.
Well that is most of the structure for the model now complete, and progress will slow a bit as I have quite a heavy Online teaching commitment starting from tomorrow, but will keep you posted when I get a chance to get in the workshop in between Skype and Zoom sessions with Norfolk's finest Engineering students!

I had a Moonglow in around 1970, also used a Merco 61 - beautiful to fly, so smooth.