1/24 scale DH Mosquito for rubber power.

[Prosper]

Hi pedwards - I've often thought of a gopro copy - not just for modelling - but I can't figure out how they handle data storage. I mean my portable camera can generate .mov files of multiple gigs in less than a minute at high resolution - so what happens when you gopro a 1/2hr walk in the countryside, even at medium res.?

Hi John -

By the way that's a nifty freewheel setup on your prop!

top marks for noticing, but I wonder if you can divine how it works from the photo? I invented this early in my aeromodelling days, probably about the time I joined HPA. It's very unobtrusive IMO but does involve a tricky mechanical solder which I don't look forward to.

Flight Report

Yesterday had almost zero wind all day, and the cattle weren't around much. The motors had been 20" 7/32" Tan SS - 2 loops of 1/16th and one of 3/32. I replaced them with 4 16" loops of 1/16". I made some adjustment to the rudder to anticipate the extra torque but it wasn't nearly enough. On about half of the motors' safe turns the model took 2-3 seconds to rear into a barrel roll to the left, over the vertical and dive almost vertically onto the frozen ground. It bounced backward. I did that pained, wincing "oh well . . . there goes that, then" thing, but amazingly the model was hardly damaged . I had to repair a tailplane spar, a bit at the back of a nacelle, some cracked sheeting at the front of same nacelle, and the pendulum arm had snapped under the momentum of the 1 gram bobweight. I even had time for another try before dark - just 350 turns per motor, with the downthrust on the left motor halved, and a bit more right rudder and down elev.

That worked well. The power increase has transformed the model. It did rock its wings a bit at one point, but okay. The flight ended with a tightening right spiral though. Against the torque there's plenty of right aileron and some right rudder - so no surprise it spirals right as turns run out. I'll have to play with thrustlines to manage torque if poss. It was fairly pitch-stable, and flew at a believable speed too, so I can almost forgive the need for noseweight.

Today I gave it 400 turns and it sailed off - lovely! Except that it sailed off towards a 'built up area'. Thankfully captured by a shrub, not smashed into a wall. No damage except the right aileron needs to be hooked up to its link to the bellcrank. And the ever-increasing potential danger of me teetering at the top of a wobbly stepladder. The model was 10-12ft up.

Stephen.

[Prosper]

Over the years I sometimes considered a Mosquito model. I would dig out my Plans Service drawing and peruse it. Nope. Not nearly enough wing for that fat fuselage and those fat nacelles. Too damn curvy. Then recently I thought what the hell, and started looking online for information and images. I noticed right away that the Mosquito 'bodies' (fuselage and nacelles) didn't look very curvy or fat. Well it turns out that yet again I was fooled by believing drawings. Surely I'd abundantly proved to myself aaayges ago that nearly every drawing out there is rubbish?

Actually arriving at a believable shape involves much much poring over many many images. The three examples attached below were very useful, and actual measurements from a NACA Report, and videos, and 'walkaround' image collections including inside views showing fuselage frames. I can't claim my conclusion is correct but it's a durn sight better than my Plans Service drawing, which I bought as a teenager, and '3-views' in books like Squadron/Signal monographs.

Stephen.

[Mark.]

I only know of one accurate drawing for the Mosquito. I was fortunate enough to be allowed to measure certain areas of a Mosquito at the DH Museum, which were then converted to the scale that my drawings are in - perfect.

The Mosquito plan I used for my build also had the scale sized fin, wing and tailplane area.

When I remade the fin and tailplane, I also increased the depth of the airfoil section as well on the tailplane. It's a lifting tail, and oh my word did it have a massive effect. It caught us off guard and the Mossie came down heavy. Good job I've got well practiced at the repair work! Ha!

Regarding your propellers, how have you set the pitch of the blades? Are they x amount of degrees at x distance?

[pedwards2932]

They use the mini sd cards so you can get a pretty large 64 gig card.  Mine came with multiple batteries so you can change out if you need more power.  The only issues I have with them is you can digitally zoom when you edit the mov but the camera itself won't zoom.  I also had one that held my phone which really looked ridiculous but took pretty good movies.  With phone you can use verbal commands. "Shoot" will take a picture.  "Start video" will take a movie.

[Prosper]

Ah, I see. If you've got a lifting tail, then presumably it needs to have lots of area, and it also adds to the total lift, which should make for a very buoyant model. Measurements from a real Mosquito - can't beat that!

The blades are currently 26°at 75% diameter. The blades are set simply by the slots they mount into - the slots cut into the hub/spinner. Pitch can be varied by heating the blade at the root until it can be twisted, or by removal from the slot and re-working the slot to a different angle.

I hope your model finds some long grass this year.

Thanks for the info pedwards.

Stephen.

[Prosper]

I'm making the wings first.

The wing section is RAF 34, with the 'Piercy Mod' according to NACA - but they don't tell us what that mod is. The true RAF 34 has some reflex towards the T.E. but in no Mosquito photo can I see any reflex, so I'm taking that to be the mod.

The wing section retains the same thickness/chord ratio from root to tip rib.

I used to be shy of tapered S&T wings because I couldn't get my graphics program and/or printer to scale the ribs properly. I start with one rib drawing, photograph it then upload the .jpg to my PC and open it with the graphics program. Then I duplicate the rib image and rescale it to the correct chord and thickness for its position along the wing - and so on for all the ribs. The printer would print out a page of ribs all innocent-like, but on checking them the original one in the series would be dimensionally correct but the others would all diverge from the correct taper and thickness. I've tried several times over the years.

I thought I'd give it one more go, and it worked! I use GIMP, and the scaling operation works in pixels by default. This time I chose the millimetres option, and that's what made the difference. I'd never thought to try this before because why would a computer program care what measurement units it works in? Mystery.

This time then, I printed out the rib shapes on thin paper, sprayed the back of the paper lightly with 3M Spraymount, cut each rib from the paper with scissors, then stuck each paper rib onto balsa, to be cut out with a scalpel. Then this rib was placed over more balsa to cut out its opposite-wing counterpart.*

The root rib of each wing is 1.6mm thick; 4 ribs are of 0.8mm and the rest are 0.5mm. The wood is medium/hard C-grain.

*I wrote this in a past tense as if I've done all this - but no. I'm referring to the process I used to make the test model. I've only just started this new model and cut the root ribs as per pics attached. I'll probably spend much of tomorrow cutting out the other ribs.

Stephen.

[Prosper]

Cutting the ribs was not nearly so onerous a job as I'd feared - maybe an hour, if that. However I haven't yet cut the 657,343,556 little slots or notches to accept the multiple spars.

But first I've hit a snag. This is down to the leading-edge radiators between fuselage and engine nacelle. The long thin rectangular intakes in the leading edge have a small but characteristic cant to them, relative to the LE of the wing itself. They tilt up from fuselage to nacelle. In the test model I wasn't interested as this was one of many things not worth wasting time on, on a crude test model. Now I'm faced with trying to get it right. There are four ribs along this stretch of the wing, each one slightly smaller than the one inboard from it, but identical in shape. They have a forward extension to house the radiator. And because the radiator is canted, the curves of these forward extensions don't fair with the lines of the RAF 34 aerofoil.

Clear as gin, eh? Maybe some photos or sketches will make this clear. Will report back.

Stephen.

[One Cut]

Stephen, keep the Mossie away from the cows.  They love balsa and doped tissue.  Something in the dope attracts them.  Lived on a farm as a kid.  My dad had a friend who flew models on our farm. Some of the cows snuck up to his car and ate one of his models that was still in the car trunk!

Gary

[Prosper]

Thanks Gary, good story - well not so good for the aeromodeller, I suppose . . . I've noticed that the fast-growing young cattle have been extra-restive the last week or so - they charge round, head-butt each other, perform strange leaping stunts like they're trying to throw a rider, and have mass mooo-ing choruses. I think they must be reaching adolescence, in cow-years. Flying is off, what with them and the weather.

I've been kept from modelling for several days - still have a few wing ribs to finish.

Stephen.

[Lastwoodsman]

Sun Jan 25 2026     Mosquito Build

Hi Stephen.    Here is a new video about the Mosquito. 
We have one almost restored,   in out local Canadian Aviation Museum here in Windsor,  Ontario Canada.
https://www.canadianaviationmuseum.ca/museum/aircraft/


Here is the new video:
How A Canadian "Wooden" Plane Became The Allies' Most Feared Aircraft    Jan 16 2026      23:06
https://www.youtube.com/watch?v=Nnq8pQDX5eY

Lastwoodsman
Richard

[Prosper]

Thanks for the links, Richard.

Brrr! My workplace is around 10° lately - that's hampering my progress (Centigrade, BTW).

I feel I have to confess that my number of 657,343,556 rib notches to be cut was in fact a slight overestimate. In fact the number was about 170 - and as the ribs are cut in L/R pairs, that's 85 cuts. Huh - serves me right for using Governement Accounting software to calculate the intitial estimate.

The photos are self-explanatory, I guess. Pic 2 is staged to give an impression of how quick the notch-cutting is. Pinch the rib pair between finger and thumb, close to the cut for max. support, and stroke the razor saw backward - next!

Stephen.

[Prosper]

Hi folks, a little progress here. I hope the work speeds up soon but things get in the way. The pic is of the 'working drawing' I made to figure out the wing for the test model. It uses rock-solid information - I have the fuselage width, the root and tip chord lengths, and the L.E. sweepback. There's lots of erasures and additions as I figured out a design. A couple of erasures and scribblings-out came because I used some info from the original Plans Service drawing I showed in post #16. Principally the trailing-edge extension of the engine nacelles (shape wrong; size wrong), and the outboard aileron rib (it's parallel to the a/c centreline, not perpendicular to the aileron L.E. as the Plans Service drawing has it).

While I think of it, the Plans Service drawing is labelled "Drawn by: XXXXX" and "Traced by: XX XXX". What's the difference between drawing and tracing?

[Prosper]

The mainspars are of hard 0.8mm, tapering in width towards the wingtip. Pic 2 shows an assortment of tools for cutting rib slots in the trailing edge (medium 3.2mm balsa). The implement that's arrowed is a piece of thin plastic card with squares of abrasive paper stuck to either side. The last two photos show the importance of getting the ribs to fit properly in their T.E. slots. Not only can one encounter wavy-rib, but mal-positioned ribs can cause the mainspar to go wavy too - it's infectious!

Stephen.

[malc]

Hi Prosper, fantastic to see your process, plese keep posting!

Pre 1980's, before the age of CAD, drawings were all done on paper by the designer in pencil. These drawings were often revised and changed through the design process, leading to what could be (depending on the fastidiousness of the designer) a pretty 'tired' looking piece of paper. Also paper is not a good archive material for a drawing that may be handled a lot and not necessarily treated very well!

When the drawing was approved by the chief designer for release, it would go to be traced, in ink on tough tracing paper, this work was often done by women. You could tell where they worked as the floor would be peppered by their heel marks where they stood at their drawing boards. (Where I worked as the floor was orange painted cork tiles). They would then 'spike' the paper drawing, which means tearing off the bottom RH corner and putting it on a spike, so everyone could tell what had been been traced. The inked tracing would be then submitted to the drawing stores. The original paper copies were destroyed.

One designer always made lots of graphite smudges on his paper drawings, so the others used a rubber to draw mushrooms in the smudges....

Malc.

[Prosper]

Thanks malc for that thorough explanation - very interesting picture you paint.

Because work on this model has been so bitty, I haven't taken photos. I've reached the stage of glueing things together. The wing is in a simple jig that does nothing but hold the front spar (top and bottom spars in this case). I think I made this jig for a Martin-Baker MB.5 model, but it works for the Mosquito wing too.

There's a stiff strip of 0.8mm balsa fixed to a piece of white card. The strip has vertical strips alternating along its length - one behind; one in front; one behind . . . (green arrows). The spar/s are slotted into this arrangment, thus guaranteeing straightness in plan. The metal rule is just checking straightness in front elevation, and the card template is checking the angle of the ribs to the spar.

Stephen.