Scratchbuild 84" Depron DH Mosquito

[Philip Rawlinson]

Jebus I've developed a stutter

[Shane Sunday]

Absolutely Fabulous! I go away for a week to work on a project and this is what happens? Today I'm awaiting the arrival of a stepcraft machine. Hopefully I can get a chance to build more with the help of the machine. Then at least I can pretend to be as deft as yourself. That canopy is well done. Tapping off the frame work can be so fiddly. I've a Propper vacformer here in the shop and can't force myself to buy them anymore. Although getting my hands on the raw materials can be more dear than purchasing a prefab one. Those struts look great you're so very lucky to have your very own McGuiver. Ours is unfortunately not too well these days. Every club needs one. Keep them coming... life is more pleasant this way.

Shane

[Electriflier]

Shane,

Thank you kind Sir!. CNC Router eh? That's got to help!

Phil, yeah, it'd be good to catch up on progress.....see you Saturday.
Speaking of progress, again, a little more to report for those of you following the build. The tailplane needed skinning and so, first thing this morning was the first job. 3mm white depron was used to skin the top and underside of the tailplane. I will be removing a section in the centre of the tail to ensure the tailplane 'plate' slides and locates into the slot in the fuselage which I know is set at 0% incidence to the centre line. I also will be removing a section in the centre of the elevator once I have double-checked the measurements.

I also epoxied a 1/16" ply plate at the seat area of the underside of the tailplane to add a little more strength.
Note the square cutout in the ply plate. This is where the vertical stab balsa trailing edge will fit through the horizontal later. As mentioned, the balsa trailing edge, (which was left over from the tail/elevator) is to fit down through this hole and at the same time, glued into place along the T/E of the vertical stab.
At this stage, I decided that it would be best if I glued the horizontal stab in place so that I could work on the rudder/steerable tailwheel, which needs to pass through the horizontal. I used PU adhesive to fix it in place and as you can imagine, whilst the glue was curing, I was constantly measuring and checking for perfect horizontal and vertical alignment. I had to nip out at this stage and so, the tail had plenty of setting time before I came back and started on the rudder.
Ooops, forgot to mention, I removed the centre-section of the elevator to give me the splt elevator config' After removing the centre bit, I finished off the inner edges of the elevator with 3mm depron end caps (pic above).

The rudder, I had already cut from the main vertical stab and first job was to trim the elevator width to allow for the 6mm thick balsa trailing edge of the vertical stab' and the 8mm thick balsa triangle that I would be using as the leading edge of the rudder (as per the elevator). Using the same methods applied to the elevator torque rod assembly, the 12SWG piano wire will pass through the horizontal tail plane (bushed by using the outer sheathing of a snake) where, on the underside, I'll utilise another of the 'tiller arm' type control horns. The wire will then be bent into shape to form the steerable tailwhweel leg.
The observant of you will have worked out that it was quite a feat to get the rudder hinges to slot into place!!! What a job!!
Anyhow, once they were slotted firmly home, were CA'd into place. That's about where I ended up today. doesn't seem like much progress but what progress there is, I'm happy with!

[Philip Rawlinson]

Roll on Saturday

[Shane Sunday]

I have that same Model cradle and wow that model is huge? Really like your method for building the elevator in one piece to be split once you've got the wire joiner in place. I have one of those handy dandy Slec hinge slot cutters and it's still a PITA.

[Electriflier]

Briefest of updates....
Over the past few days, build time has been sporadic to say the least. Again, not through lack of interest....... just been busy!
Managed to meet up with 'MacGyver' Rawlinson today to get a look at the retracts/oleos. Lovely job Phil!

Promised him that I would post a picture of the model stood on its wheels this evening come hell or high water so, here you go Phil.....

Other jobs I've managed to get done over the past few days. Tail wheel fitted, snakes re-routed and connected at the tail end, canopy now glued in place after Phil painted the Co-pilot, underside of the wing centre section skinned in 3mm white depron (after routing the aileron and retract cables through the blue foam). Hoping this week to start work on the undercarriage doors (sorry it's taken so long Ian!) and maybe, just maybe, fuselage skinning................'the best laid plans.............

Edited By Electriflier on 04/10/2015 19:16:37

[Philip Rawlinson]

Looking good Roy, take your time mate, the point of the exercise is to enjoy what we do and believe me I'm getting a whole lot of enjoyment from this side .

Watching in awe .

[Electriflier]

Today I managed to get the elevator and rudder servos centred and connected up before I either sealed up the servo compartment or................ couldn't bring myself to just skin over the top and so, like the front battery/receiver compartment, fashioned a 'lid' from some scraps of 6mm depron to cover the servo area. The lid of the hatch cover also from 6mm depron was worked flush with the fuselage formers so that when skinned in 3mm depron, all that'll need doing is to cut around the hatch to ensure a nice neat fit
I have been a bit concerned as to how to secure this hatch as I dont want latch catches visible on the top of the fuselage. Bit of a brainwave...... and I dont get many of them these days......I'll use the plug-in antenna mast as a hatch retainer. (i'll explain more when I get around to making the antenna mast)
Also, secured the aircrew and canopy onto the model as I was getting a bit tired of the pilot and co-pilot baling out every time I moved it.
Maybe, just maybe, tomorrow will see the start of either the retract door assembly or skinning of the fuselage. We'll see what tomorrow brings.

[Electriflier]

Well, I have just finished looking at Ian101's beautiful Lancaster..... lovely model!!!
As I said yesterday, any time I had to spend on the build would be either skinning or the retract doors. The retract doors won!
I set about today with the intention of finding the simplest way to operate the retract doors and I think I may have done just that.
Looking forward to starting to work on the actual doors tomorrow and my next blog update should explain the simplicity of the workings of the retract doors.
Cheers
Roy

Edited By Electriflier on 06/10/2015 21:36:52

[Ian101]

Thanks for the plug Roy. I am trying to finish it before you finish this beauty!

Intrigued by your retract doors.

[Keith Simmons]

May I ask how you did the door's. Was the idea copied somewhere?

[McG 6969]

Hello Sir,

I’ve been silently subscribing to your build since you started building your splendid Mosquito.

If you haven’t yet decided on the decoration/markings of your model, I was thinking of suggesting you this ‘Red Sea Shark’ version.

The Red Sea Sharks (French: Coke en stock) is the nineteenth volume of The Adventures of Tintin, the comics series by Belgian cartoonist Hergé. The original comic is from 1958 and reprinted over and over again since.

The "Coke" referred to in the original French title is a code name used by the villainous antagonists of the story for African slaves.

The Mosquito is flown by a Khemedi Col. Achmed and mistakenly destroys two of his own armoured cars half way the story. The comic is about modern slavery and the Khemedi state is behind this trade. As you can expect, Tintin, Capt. Haddock & Szut (a Khemedi pilot discovering in time he joined the wrong people) save hundreds of people from slavery.

This Mossie version has been build up by some Belgian & French modelists at a small scale (Airfix or Revell 1/72) but no trace of some bigger models on the net. Most of them even didn’t bother about including the Arabic registration… but almost all replicated the ‘in square’ (instead of the ‘inline) position of the 20mm nose guns.

I thought this colour scheme could be rather unique as far as both you & your ‘McGyver’-partner like it too, of course.

Just being a thought, here.

 

 

… and please, go on showing us the way it should be done.

 

Happy building

 

Chris

Brussels, Belgium

 

Edited By McG 6969 on 08/10/2015 12:17:23

Edited By McG 6969 on 08/10/2015 12:17:57

[Electriflier]

Good afternoon,
Keith, I'm not sure what you mean by 'was the idea copied somewhere?' but I'll try and answer your first question in the log entry.
Chris, many thanks for the intriguing theme suggestion for the Mossie' However, Phil has already stated that he would like to see it finished in the grey/green camo' pattern complete with invasion stripes. Nice idea though
As I mentioned yesterday, the retract doors would be the focus of my attention today and so, after removing the 'test' depron doors that I showed you yesterday, set-to with the ones that will be on the model.
Being that the doors might take a fair bit of abuse what with the retracts pushing on them from the inside and the rubber bands pulling on them to close the doors, I made the door 'plate' from 3/16" balsa sheet.
Now, the wheels protrude from within the well my around 1/4" and so I had to build around them by removing a section from the doors. I would then be able to build around the protruding wheels with some balsa ribs.

Like so......
I added some 1/4" square balsa strip along the edges of the depron wheel wells to allow me to drill and hinge (pin hinges) the doors to the actual wheel well. After much trial and error getting the doors to swing reasonably freely. I test fitted 2 x 6" rubber bands into each well. Difficult to explain but i pinned one end of each rubber band into the floor of the wheel well, close to where the tyre sits when retracted. On either side of the tyre.
Then the rubber bands were crossed as I brought them up to the doors, where I pinned each end to the door lip 

.
Again, many ups and downs later, found the sweet spot on the doors and the correct tensions on the rubber bands to get the doors to open and close every time. I marked off the rubber bands at the correct length and then made up 4 lengths with balsa stoppers on the end. These, once passed through the side walls of the retract bays would anchor the bands into the bottom of the wheel wells.
The rubber bands each glued around a strip of balsa

One of the rubber bands anchored in place ready to be secured to the retract door.

Cutting a very long story very short, once I had fastened the rubber bands in place, skinned the doors in 3mm Depron. Quite pleased with the results as they do open and close every time and look reasonably tidy now they are skinned.
And here's the proof.............


That's it for today.............
Cheers
Roy

Edited By Electriflier on 08/10/2015 18:00:26

[Ian101]

I am really impressed with that and so simple.

Ian

[McG 6969]

Thx for the answer, Mr Electriflier.

I can imagine you both had already a deco scheme in mind.

But anyway, it could bring some other Mossie builders to some 'un-classical' idea.

Still following, and... happy decorating.

Chris

Brussels, Belgium

[David Holland 2]

Evening Roy. This might not be the appropriate thread in which to seek your advice, but here goes. I have "lurked" quietly in the background of all your builds and have become more and more impressed with the possibilities of Depron and have decided to have a go. I have drawn up a 44inch Britten Norman Islander which will win no prizes for originality but nice boxy fuselage and constant chord, constant section wing and tail make for a simple first attempt, plus the fact that I have always found it a very appealing design. I intend to use balsa leading and trailing edges to improve ding resistance plus one or two formers in high load areas but I have no idea of a suitable depron to balsa adhesive?

Eagerly awaiting the next instalment of the Mossie build!

Thanks in advance, David

[MattyB]

UHU Por is the glue of choice for sticking Depron to, well... pretty much anything else really! Other than being a little pricey it is a really good general adhesive for model building - every modeller should have a tube in their glue box!

Edited By MattyB on 10/10/2015 08:34:13

[perttime]

Posted by McG 6969 on 08/10/2015 18:57:29:

...

But anyway, it could bring some other Mossie builders to some 'un-classical' idea.

One more fan of fantasy and what-if designs and schemes reporting....

Another Mosquito mutation would be the Finnish VL Vihuri paper project that was basically a Mosquito copy powerd with DB 605 engines.

**LINK**

[Electriflier]

Evening.....

David, I second MattyB in his reply to you and would have answered sooner had I had the chance. Yes, Uhu Por is the adhesive of choice to give an instant strong bond between the balsa and the depron skin. Just be sure to align it correctly before applying any pressure as you'll not get it apart in a hurry!
Pertime, welcome and thanks for the input. Very interesting suggestion which made me go away and do some research. That's another part of the hobby that I truly enjoy......... learning!!!

Sadly, no photo updates this evening as, well I don't have any!
Been busy in the shop I'm pleased to say and so the odd minute here and there is all I could afford. Phil called in to sign-off the retracts. THink he was suitably impressed.......
He took with him the oleos to do a little more work on them and also, gathered a few measurements for the armaments that hopefully, he will be manufacturing.

I can report however that the motors spun in anger today and we had a worrying moment when it appeared that there was a huge amount of torque effect from motors spinning the same way. I should point out at this stage that the decision has been made to go with 2 x 13" 2 bladed prop's as 13" 3 bladed would put too much load on the Esc. The 2 x 13" prop's produce 710W of power each which a constant draw of 45A. The pull to the left was resolved by setting the throttle end-points on both ESC's. Only one had been done in the past and the difference between the calibrated and the one not calibrated was measurable. Once both end points were reset, there was no noticeable pull in any direction other than forward and by pull, I mean PULL!
Phil was there t the time and seemed pretty impressed by the amount of power he will have 'on-tap'.
I will take some photo's of the ESC location and any other new developments for the next update and in the meantime, start working on cutting out the Aluminium spinners and getting the nacelles prepared for the 3mm Depron skin.
Unitl then....

Regards

ROy

[David Holland 2]

Thanks Roy, MattyB and Tony (by PM) re the glue query. I tried canopy glue, just out of curiosity, and it stuck depron to depron and depron to balsa like wotnot to a blanket. Is this a viable alternative where a bit more time to line things up is useful? Takes a lot longer to dry but not a problem for doublers and the like I would have thought.

David

[Electriflier]

Good Evening,
As promised, the 60A ESC' have been sited just between the first and second formers of the nacelles. Stood on their edge, presented face-on to any incoming cool air. The wires to the receiver will pass along the radiator front section of the leading edge and be covered with a strip of 3mm Depron. I removed the red wire from the cable as I will be using a separate 6v battery for the flight pack and not relying on the 2 x 4S lipo's.

The 2 Esc's were 'Y'-leaded to the front receiver compartment at the front of the aircraft and plugged into the 7 ch receiver that Phil has supplied.
At this stage, prior to commencing the 3mm depron skinning, I had to address the ali' spinners. By that I mean, they needed cutting out to facilitate the 2 bladed props'.
Not a job I relish and one that you only get one shot at so the measure 25 times and cut once rule applied!

I marked the spinner backplates along the outer edges of the props. measured the height of the props' and then removed them from the model. I then assembled the spinners off the model and transferred the marks onto the spinners themselves. Again, measure many times before cutting, I decided it best if I copied these measurements onto a piece of plasticard and then drew the required shape freehand. I cut the shape out of the pasticard and tried it over a prop, on a level surface to ensure sufficient clearance. Once I was happy, held the plasticard to the spinners (as a template) and drew the cutout shape onto the spinners. Dremel came in handy here!! It seemed to take an age to cut out the slots in the spinners as again, I was aware....... one slip. Long story short, all good, no errors thankfully.
Now I was sure that the spinners were complete, I was able to tighten everything up (see pic) and check the clearance behind the spinner was sufficient and even to allow smooth rotation. I had to sand some parts of the blue foam to get it looking something like.
That done, the bit I was looking forward to had finally arrived. Skinning the nacelles. - WRONG!

No Exhausts!!

I had overlooked the exhaust area of the nacelles so I had to forget any thoughts I had about starting to apply Depron.
Referring to my drawings, I found the correct measurements for the exhaust back plate and recessed some 6mm Depron into the side walls of each nacelle.
I'll not be doing any work on the exhausts themselves yet but I needed to do this work on the backplates before I did anything else. I needed this plate to sit back from the outer nacelle skin and so added some 6mm strip top and bottom to catch the edge of the 3mm depron skin when the time came.
As most of you who know me will know, I try to use white 3mm depron wherever possible as I find it less susceptible to dents and dings than the much easier to use, softer, grey depron.

The first piece of 3mm white skin was applied to the underside of the nacelle which went almost halfway around the circumference of the blue foam. I'm happy enough to 'panel' difficult areas of the skinning so long I'm happy that strength is maintained in the bond. That's to say, I try to ensure any bonds in the skin are offset from each other. UhU adhesive for those of you who haven't done any skinning yet, is by far the best glue to use for this part of the build. You're able almost to pull and knead the 3mm Depron around complex compound shapes as the glue just grabs insantly (after the obligatory 10 minute wait). OK, you use a lot of UhU and it's not all that cheap.

Anyhow, a few hours later, one nacelle is skinned and I can look forward to doing it all over again tomorrow!!!!
Cheers
Roy

Edited By Electriflier on 13/10/2015 21:20:24

[Philip Rawlinson]

Fanbloomintastic

[Philip Rawlinson]

 As the build is moving along at a terrific pace I thought I would have a bash at making something resembling the cannons for the nose. A bit of brass tube was heated up and forced onto the end of a tapered punch to make the fluted end then a few slits formed in the barrel under the pillar drill. A bit of fine line masking tape was used to create a raised ridge followed by a dusting of black aerosol. The cannons will be a push fit onto wooden dowel glued into the nose to allow them to be removable so avoiding damage during transport. Just need to get the o.k. From the depron guru and I will make the rest.

Edited By Philip Rawlinson on 13/10/2015 22:12:16

Edited By Philip Rawlinson on 13/10/2015 22:14:22

Edited By Philip Rawlinson on 13/10/2015 22:15:23

[Rosco]

Hats off to you Electrifier.

I'm watching your build in awe.

I must say though that I'm always a bit worried when electrics are concealed within builds and as a matter of course, I always try to make things accessible.

As I say, I'm watching your build in awe and it is truly inspirational stuff because it makes my fingers itch to start on another build.

I look forwards to the rest of the build and the report on its first flight (vids are great!)

Rosco

[Colin Leighfield]

Roy, I continue to learn from you. Having had some success with my (less ambitious) Depron project, I'm thinking about another one. We will be off to Spain for 3 weeks shortly and I might be doing some drawing while away. That's how the XB42 came about and it's worked out very well. What next? I've got a good stock of blue foam, 6mm grey and 3mm white aero quality Depron, so the ingredients are there. I think I know what it will be. A low Kv motor with a large prop would be necessary.

I still fancy the idea of catching up one weekend and bringing the Mixmaster. What do you think? I need to think about techniques for improving the finish on Depron which hasn't been glassed over and clearly matt camouflage is a better bet than gloss silver for that purpose!

I'm interested also in the technique you are using for creating the spinners. That is one of the most challenging features for me with some of these scale designs. Also I can balance a prop ok but haven't yet learned out how to balance a prop and spinner together. It might dawn on me eventually.