Scratchbuild 84" Depron DH Mosquito

[Electriflier]

Still struggling with the images.....

Colin, you mentioned washout earlier. Sorry I haven't replied earlier but things have conspired against me!!!
I do agree with your comments and I'd hate to see Phil having to BALE if he loses a motor!

I have incorporated 2 degrees of washout between the outer nacelle and the wingtips. Adding +.2 of a deg to each of the ribs totalling 2 degrees by the wingtip.

Hopefully, you can see this in the illusatration below?

​

[Philip Rawlinson]

You certainly don't hang about .

To bale out is not an option, if need be I am going down with the ship

[Electriflier]

Posted by Monz on 01/09/2015 21:19:59:

Roy, do yourself a favour and revert to your previous version of Windows. Best thing I did and I only had 10 for about 30 mins!

Mozzie is looking good so far.

Monz

As i type (on iphone), my PC is doing just that! Reverting back to a stable version of Windows 7! What a waste of time that was! My CCTV cameras didnt like it, my music workstation seemed unstable, unable to paste into the browser for goodness sake. Anyhow, you've helped me make the decision-thank you! Hopefully back to regular, almost stress-free posting before too long.

The Mossie' should make for a nice model and quite honestly, im looking forward to getting started although ive been at the drawings almost constantly for 2 weeks or so. Time not wasted though because, as youll know, you get to know the aircraft well whilst youre looking at each component.

[Electriflier]

Good evening,
Well, firstly, thank you Monz for bringing me to my senses with regards to rolling back to Windows 7. Quite a painful experience though in that once I had rolled back, my PC refused to recognise my network adaptor. Nothing seemed to cure the problem so I had no choice but to format my machine and start afresh. Fortunately, I'm a 'belt and braces' man when it comes to system backups so thankfully, I lost nothing other than a couple of days reinstalling everything. Anyhow, that's done with now so I have been able to concentrate on the build.
The plans were taken to our local printers who turned them around very quickly and reasonably I might add. They were done within a couple of days and although smaller than plans I have produced in the past, still 3M long!

See Pic

The obligatory 'Me stood on plans' picture
I spent a while gathering together some of the bits that would enable me to get cracking on the nacelles/retracts/motor mount area. Plywood, light ply, captive nuts, hardwood bearer for the retracts etc and then cut the plans in to manageable pieces. The area of the plans that covered the nacelles looked like this....
The sides of the battery box are to be of 3mm light ply and the floor, front and rear from 6mm normal plywood. This area of the model is the place that carries most of the loads that are likely to be placed on the model. So I have ensured that the motor will be well secured to 6mm ply whilst the retracts will be nestled into 15mm hardwood bearers which will be fixed to the underside floor of the battery box. Carrying the load through the fuselage and wing centre-section on the lightweight 22mm aluminium tubing that was once a tailboom on a 50 sized heli'. and blue foam centre section that will pass through and be built into the fuselage.
I left my phone at home today so was unable to take many photos of my progress but as soon I got home, took a few pics of the components that I had cut from both light and normal ply sheets.

The battery box will be in the nacelle in each wing and the bare components can be seen here
You'll notice that I have already drilled and fitted the 3mm captive nuts into the motor bulkheads. (If you notice on the plans, the motors sit quite low on the front of the battery box to get the correct alignment).
I have drilled out the 6mm ply floor with a 13mm forstner bit to cut down on weight and will do the same to the side pieces of the battery box later. SO as to ensure that the battery boxes hang vertically at 90 deg rather than follow the 3mm of dihedral, the side panel of the battery boxes are of a slightly different size so that with both side pieces stood vertically on the workbench, the holes that take the ali' tube introduce the desired 3 degrees by being slightly offset. (Thank goodness for the drawings)
Anyhow, today finished off with a dry assembly of the said parts and hopefully tomorrow, I can start mixing some epoxy.

Hope this lot makes sense?
For now..........
Roy

Edited By Electriflier on 05/09/2015 21:48:20

[Martian]

it makes plenty of sense Roy and looking good already

[Danny Fenton]

Looking fabulous Roy, it is great to see your process.
Cheers
Danny

[Electriflier]

Cheers Martian, Danny.
Managed a little more on the Mossie today. Needed the bench tools that I have at work so locked myself away at the shop for a few hours.
I needed to start on work that could only be done at the shop requiring electric fretsaw, bandsaw, bench press drill, hot wire cutter etc. On this build, it seems logical to work on the nacelles, inner wing section first then the fuz leaving the outer wings 'til the last job almost. As I think I've already mentioned, I'll be using blue foam for the section of the wing that passes through the fuz and the inner wing roots to the nacelles. The section that is embedded in the fuz I'm leaving as a square block to make alignment and wing dihedral angles easier. The first job today therefore was to cut some lightply wing rib templates (wing root to inner nacelle) Ribs 2 and 4. I spray-mounted the two pieces of light ply together so I only had to cut each rib once. Whilst they were still lightly tacked together, I reamed out the 22m hole for the wing tubes. Not having a 22mm drill bit, I filed some nasty looking teeth into the end of one of the ali' tubes and carefully wound them through the two ribs. Went through quite easily!

The blue foam sections of the wing are made up of 3 pieces. The central fuselage block and the two inner wing pieces. Each piece was cut from a block of foam (100mm x 600mm) on the bandsaw which ensured each cut face was at right angles and clean. The 2 blocks that made up the inner wing sections, I fastened wing ribs 2 and 4 on each side (after quite a lot of measuring, checking and double-checking) of each block and fired up the hot wire cutter. Not a job I enjoy to be honest! Nonetheless, necessary and thankfully, didn't take too long.
Whilst the ply rib templates were still fastened to the now airfoil-shaped wing sections, I again used the saw-ended ali' tube to cut the hole through the foam block between the ribs. Care had to be taken to get the cut to line up with the hole on the other side.
It's worth pointing out at this stage that all wing ribs (apart from the 2 that make up the battery box sides) are at right angles to the ali' tube. By this I mean, the 3 degrees of dihedral is achieved by removing a 3 degree slither from each side of the centre blue foam block.
Next job, I removed the rib templates from the foam blocks and measured and lined up Wing Ribs 2 on each side of the centre foam block. When correctly lined up and screwed in place, I again reamed out a hole in each side in which the Ali' tube will be secured eventually.

After I'd done this I removed the ply rib templates and PU glued the inner wing blocks in place using the ali tube to ensure correct alignment whilt the adhesive set.
So, the sum part of my labours can be seen here.
Might start using some Depron soon!

Cheers
Roy

[Philip Rawlinson]

Got to say I feel ever so slightly guilty lapping up the sun and getting in a bit of flying here in France while you beaver away back home but I know you love it really

The quality and attention to detail of your work ia a joy to see and testament to the fact that all your lovely creations fly so well.

Sitting here with a glass of chateau de falling down juice and enjoying every minute.

[Shane Sunday]

Ah sir it is a pleasure to see you at it yet again. This time a twin boom! would that I had the time. But I will follow your build closely in hope that one day I can put some of what I learn into practice. subscribed To **** as they say over here.

[Colin Leighfield]

Very impressive Roy. I must get my head around CAD, it is clearly a big advantage and would certainly help me. Every time I look at it I end up scratching my head and going back to the pencil. The XB42 was inspired by the Mosquito, which the Yanks hugely admired. A bigger one in Depron, with retracts, would be a challenge and suitable contra-prop motors are available. Later maybe. I've got the blue foam as well.

[Electriflier]

Hi,
As you may have noticed, the future owner of this build is hard at work researching the bottom of his wine glass!
Can't fault him.......so long as he brings me a bottle back
Welcome back Shane...... nice to have you tagging along. Colin, I cannot profess to understanding CAD in any way. I have used MS Visio for quite a long time now and find it quite straight forward to use. CAD drawings can be imported into Visio but the guys at our printshop are quite happy to print from Adobe .pdf files which Visio can export to.
A little more progress to report anyhow.
I have now glued all the battery box wooden parts and secured the retract hardwood bearers in place underneath the floor of the battery box. The 22mm Ali' wing tubes have also been PU'd into place within the blue foam inner wing cores. To add further strength across the centre blue foam section, I have inserted and glued in some 6mm Carbon tubes. I simply cut some saw teeth into the end of the Carbon tube, stuck it into the drill and drove it in through the rear micro bore plastic tubes that are toward the trailing edge of the wing.
DrilIing the carbon tubes into the centre blue foam block.
I drilled one PU-coated carbon rod into each side that were made long enough to reach the centre of the wing centre block resulting in a very strong section that should hopefully handle even the roughest of arrivals!
Hopefully you can see the degree of dihedral from the picture taken from the front of the wing centre section.

Time now for Depron!
I spray-mounted the drawings of the component parts of the nacelles and carefully cut them out. Again, making sure the cuts were at 90 deg and not on a slant. A section I ad not drawn was the 6mm retract wheel well side walls so after another hour drawing was able to produce and print out the parts accurately. With all parts now cut , I was able to dry-assemble the bits and check their fit. All good!
An hour or so later, I had two identical, part-finished nacelles that were starting to take shape as you can see here:- More tomorrow I hope.
Regards
Roy

Edited By Electriflier on 09/09/2015 21:48:05

[Dave Hopkin]

Looking good and moving fast,,,,,

[cymaz]

Another stunning build

[Philip Rawlinson]

Do not worry Mon Ami , I have been spending my time wisely sharpening my flying skills in tricky conditions and visiting numerous vineyards to get you some of the finest red falling down juice to reward your efforts.

The work so far on the build is looking awesome.

[Electriflier]

Evening,
'Tricky conditions'........
Yeah, OK, I believe you!................enjoy my friend!
The build, I have to say, for whatever reason, is by far, the most enjoyable yet. Don't ask me why because I wouldn't be able to answer you honestly. Strange................
Today I was able to get cracking again on the nacelles. They're probably the most technically difficult part of the build in that they need to be strong yet light, carry the retracts, carry the batteries, ESC's and motors. The good thing is, I am able to work with the nacelles as individual components. OK, everything has to be done twice but with the nacelle unit off the wing, it's really easy to work on them and so far, I have been able to cut two sets of everything and...... they fit either nacelle!!
Again, the accuracy of the drawings has paid dividends on this build.
Firstly, I added the 6mm depron 'keel' shape to the front lower section of the nacelles.
I have removed the 3mm lightply ribs from the outer section of the blue foam as they were only there for the hot wire cutting. The nacelle will eventually glue up to the blue foam when the time comes.
I have drawn, printed and cut out the nacelle longerons from 6mm white depron and PU'd them in place along the body of the nacelles which has added very little weight but an immense amount of strength to the structure.
The wheel well area has been boxed off in 6mm depron and although the retracts are not yet installed, I'm able to access the area quite well for when that time arrives. There seems to be plenty of room.

I have started to do a little more work on the battery access hatches to the top of each nacelle. Just behind the first former in the nacelle, I have added a 3mm lightply former that serves two purposes. First one is to protect the batteries from the end of the motor shaft that protrudes through into the battery box and the second, to act as a front stop for the battery access hatch. I have cut a slot into this former to allow a 'tongue' from the front of the access hatch cover to locate in to. To the rear of the access hatch, I have glued some more 3mm lightply to act as the 'latch-catch' to the access hatch panel.
Each access panel lid is again made from 6mm depron and I've epoxied in some sprung hatch-catches into the rear edges to locate into the said ply formers. The hatch panel lids will eventually be brought up to full depth with blue foam and shaped accordingly.
I might also mention at this point that the nacelle front cowl, the rear of the nacelle which is very boat hull-like and, as already mentioned, the battery hatch panel lids, will be finished in blue foam.
Unusually, I feel that the build is progressing quite quickly although I am in now way rushing the process. That said, I can see me spending a good few days yet on each nacelle and I haven't even started on the retract doors yet......... maybe I'll find myself eating my words?
Looking forward to sampling Phil's falling down water!

Cheers
Roy

[Philip Rawlinson]

Awesome !!!!!!!!!!!

[Electriflier]

Evening,
Well, today has been hard.......
After receiving news of a close family bereavement, I just had to keep myself busy. Building model aircraft seems almost trivial in the scheme of things but believe me, at times like this, being able to immerse yourself and focus on something that you enjoy, helps you through.
I was quite happy therefore to sit and work with the nacelles in my lap, shaping the blue foam nacelle cowl and battery access hatches.
I had been down to the shop earlier to cut the blue foam blocks to the rough required shapes on the bandsaw. I slightly over-sized all the parts so that I could be allowed a little more breathing space when shaping.
The cowls, I prepared a ply former (Nac 2) to act as a template before cutting from 100mm thick blue foam block. I used this template also to guide the blade whilst cutting the internal hole from the cowl. Knowing this was the widest part of the cowl, also cut the smaller nose former (Nac 1) to align and screw to the front of the foam block.
Once home, I spent quite a fair bit of time with the dust mask on and my hand-held orbital sander achieving something like the desired shape.
The rear of the nacelles will be formed in the same way and so too the retract doors when I get around to them.
Short, to the point update this evening but i hope you'll understand why.
Cheers Roy

Edited By Electriflier on 11/09/2015 19:39:42

[Ian101]

Our thoughts are with you at this difficult time Roy.

[Shane Sunday]

I know exactly what you mean Roy about imersing yourself in a build during difficult times. The build is looking fantastic by the way. I'm picking up lots of tricks. May I ask exactly how you got the bandsaw blade in the center of the former? or did you just cut straight into it?

Best wishes.

[Electriflier]

Thank you for the kind messages.
Shane, you'd be correct! - I cut through the side wall to remove the centre core. No big deal because it is such a clean cut that it could be glued back together. I probably won't bother as the blue foam bits will be skinned in 3mm depron anyway.

Saturday is always a difficult day to work on any build as it's usually spent chin-wagging and serving customers in the shop. Today was no exception I'm pleased to say and I even had a visit from 'he who will be owner' after his arduous stay over in sunny France. Talk about giddy!!!
Thanks Phil for the lovely bottles of 'falling down water'. They will help the build no end Sir!
So, more today about getting small jobs addressed. Showed Phil what it might look like once the spinners arrive. I'm using the DB Sport & Scale Spitfire spinners which are 4 3/4" dia (I think).I had made provision in my drawings to use these spinners and I was relieved to see that once they were offered up to the nacelle, they were perfect in that they allowed for the 3mm depron skin that I have yet to apply.
Apologies for the quality of today's photographs. I think my phone needs the camera lense cleaning.

I took the opportunity to weigh each nacelle separately and was amazed, and relieved t see that they were within 1 gram of each other. They weigh 350 and 351 grammes respectively. I can only put this down once again to being able to refer to clean, accurate drawings.
Speaking of weights, whilst the scales were out, decided rightly or wrongly to weigh the whole centre section including retracts, batteries, esc's 1 x wheel (because I had only brought 1 with me) and anything else I could lay my hands on applicable to the finished product - Just over 3 kilo's. So, now I can hopefully predict an AUW of the completed model at around 4 1/2 Kilo's or 10lb. give or take a few oz's each way.
1400W of available power should get this bird safely and promptly off the floor I think?
Retracts were dropped into place and holes pre-drilled ready for the screws which I have yet to source. Motors were test fitted for the first time just to get and idea of how the whole thing was balancing. Taking everythng into consideration, I am pleased with how things are shaping up.
The only thing I could really do today during office hours was to cut the foam blocks that will be the rear of the nacelles.They're a very complex shape and will require lots of care and attention to detail to get them right. That's tomorrow's job so until I get them sorted...... th-th, th - that's all folks

Regard
Roy

[Electriflier]

A little more progress....
Cut the outer wing ribs from 3mm lightply and the same from 6mm depron to cap the ends of the structure. Firstly, it was now time for me to glue the nacelles in place. I used PU glue and both up at the same time so I could be sure of alignment and uniformity on both sides. I didn't need to use clamps as the fit onto the ali tube and the plastic pipe ensured a good snug fit which held itself in perfect alignment whilst the glue set.. I gave it about an hour before I glued on the newly cut outer wing ribs. I chose light ply here because the constant on-off with the plug in wings would tend to damage depron.

As I mentioned yesterday, the foam blocks to the rear of the nacelles were glued in place before I attacked them with the orbital sander. These, like the cowls will eventually be skinned with 3mm depron. I have achieved a reasonable shape but have stopped now until I get the undercarriage doors done as their back edge comes close to this fairing,
Unless you've got your eyes closed, you'll notice that the centre section has taken on the appearance of a slice of Swiss cheese. I found my large forstner bit and so drilled strategically placed holes through the heaviest part of the wing section. I reckon I removed a good 4-6 ounces by doing so Doesn't look too pretty but it'll all be covered in 3mm depron before too long.

Talking abut the undercarriage doors, they are quite a complex shape. Not straightforward right angled doors but .curved along their length as well as curved to the shape of the underside of the nacelle. Before I attempt making these, I need to know how the retractable undercarriage will fit/sit within the wheel well. Not having the 140mm sprung oleos yet, I decided to mock some up in wood.A big help when trying to work out clearances above the retracted wheels.
So, again, another day gone!
Roy

[Pilot_Chuckle]

Looking good, be interesting to see how much weight it's lost.

[Colin Leighfield]

Another fascinating build, provokes lots of ideas.

[Ian101]

Very methodical. Your builds seem to flow effortlessly.

Looking forwards to your gear doors. I have left mine until last because I haven't got a clue how to do them!!

Ian

[Philip Rawlinson]

The progress since I saw you yesterday is staggering, as is the accuracy of your finished parts.

I will again admit I could never come close to creating something anywhere near the quality of your creations and it is a real privelage to be able to fly them.

Bottom licking excercise complete , thanks again.