De Havilland Mosquito

[The Wooksta!]

[kitnut617]

you can put your handbags away Lee ---

[The Wooksta!]

Bob, whilst you're playing about with scaled up Mossies, take a look at the drawing of the jet version.  The fuselage looks scaled up.

I'm toying with a Mosquito hotrod - take a standard bomber fuselage and add the wings and engines of the Hornet for a fast low level strike aircraft.  The other idea I'm thinking of is a deepened Hornet fuselage to take a single 1000lb bomb.  Alternatively, take the cannons out and have it semi recessed.

[rickshaw]

Thats interesting.  According to the references I have, the Merlin and Griffin are approximately the same width.  In fact the Griffin is whisker narrower with the Merlin measuring in at 30.8 inches while the Griffin is 30.3.  So why would the nacelle need to be appreciably wider?  Taller perhaps (Merlin is 40 inches and the Griffin 45) but not necessarily longer (Merlin is 88.7 inches versus the Griffin at 81 inches). Remarkable how Rolls Royce managed to get another 500+ HP out of an engine smaller than the Merlin.  The Sabre OTOH, is the same width as the Merlin (40 inches), the same height as the Griffin (45 inches) and 1.5 inches longer (82.5)

What are you going on about a Griffon for, the aircraft in question is a SABRE powered Mosquito.  

A good question.  I was using it to illustrate a point I was implying.  British inline aeroengines all appear to have approximately the same width - perhaps intentionally - to ensure against a lack of supply during wartime.

I do have to apologise though, I suggested the width for the Sabre was the same as for the Merlin it isn't but it isn't significantly different either.  ~3.5mm in 1/72.  You could just widen the nacelles by about that much and no one would know any different.

The Sharp/Bowyers book says it was a proposed SCALED up Mosquito.  And if you think a Sabre is the same width as a Merlin, you need to go back and check your figures.  BTYI, photos of Typhoons and Tempests with their cowling panels off, show that there wasn't a square inch of space left between the engine and the cowlings.

Sabre Bore & Stroke- 5" x 6.5"  Horizontally Opposed
RR Griffon Bore & Stroke - 6" x 6.6" 60 degree Vee
RR Merlin Bore & Stroke - 5.4" x 6"  60 degree Vee

Look its your WHIFF.  You can do what you like with it but I'm merely pointing out that perhaps one of your dimensions is wrong and trying to save you something you seem to be worrying about, thats all.

And at that point I will leave it.

[Aircav]

Wasn't the Griffon and Merlin the same engine block ?

[Pablo1965]

Good Idea...thank to share it 

[apophenia]

Wasn't the Griffon and Merlin the same engine block ?

The blocks aren't the same. The FAA requested the Griffon as an enlarged Merlin but, instead, Rolls-Royce applied the R dimensions to a Merlin-inspired (but not Merlin-derived) block. Or as Flight (20 Sept 1945) put it: "... the knowledge gained in the Merline has resulted in the refinements which distinguish the Griffon".

The Griffon resulted from a redesign of an earlier Griffon (the R11, developed from the racing R, from the Buzzard, etc.). Bore and stroke are the same but, according to Flight, the only component held over from the R series was the crank.

For the rcord, Flight compares dimensions for the Griffon 65 and Merlin 66. These are given as OA Length 81in/78in; OA Height 45in/43.675in; OA Width 29.5in/29.825in.

Apologies for the hijack. And now back to our regularly-scheduled programming ...

[jcf]

Building on apo's hijack, a short side-bar here:

Griffon and Merlin do not have the same block nor is the Griffon 'smaller' than the Merlin.
It is in fact much larger at 2,240 in³(36.7 liters) vs. 1,637 in³(27 liters) for the Merlin.
Weight also increased with the Griffon being from @ 300 to 600 pounds heavier (Merlin weight varying by version).

The overall length measurement in the Merlin series varied from 69 inches for single speed engines up to the 88.7 inches
of the two-speed/two-stage engines. Griffon lengths varied from 72 - 81 inches, depending on accessories and in all versions
it is deeper than the Merlin and only narrower than the two-speed/two-stage models. Using external measures only gives a
false sense of relative size.

The Griffon's dimensions were constrained by the need to fit into existing/planned designs so R-R paid close attention to
packaging to keep overall length down, the camshaft drives and magneto were moved to the front of the engine. Originally
the first part of the supercharger drive was also front-mounted, this was later changed to a rear-mounted design due to cost.

From British Piston Aero-Engines and Their Aircraft, Alec Lumsden, Airlife 1994 (2nd impression 2003)

Back to the subject at hand.
Robert, even if as Sharp-Bowyers say the Sabre-Mossie was 'direct scale-up' of the DH 98 in general dimensions, this does not
mean that every dimension would be, or even could be, increased by exactly the same ratio. While a span of 65' is indeed 1.2 times
greater than 54', the fuselage/overall length would not necessarily be exactly 1.2 times longer as aerodynamic and weight/balances
issues would also impact the length. As to the interference problem between props and fuselage, try not scaling the fuselage in width
by the 1.2 factor, the canopy apparently stayed approximately the same size so perhaps while they 'deepened' the fuselage the
width was not increased as greatly?

Jon

[The Wooksta!]

... take a standard bomber fuselage and add the wings and engines of the Hornet for a fast low level strike aircraft...

Very cool idea! Something like this? Or would you keep the Mossie nacelles? Hornet tail?

Not quite sure yet, I'm just throwing an idea I had a few nights ago into the ring. That top view looks about right though.  

I'd probably keep the Mosquito tailplanes but add a Hornet fin fillet.  I've done it with a Mosquito NF38 that remains unfinished - the 38 had some serious stability problems so I added the fillet to sort them out and it'll get handed props too.  Still undecided as to the scheme it'll end up in but Dark Sea Grey and dark green over PRU Blue is a current favourite and very attractive.  It certainly looks different.

I'm liking the idea of hybrids and manufacturer kit bashes in general more and more.  The RR Eagle engined Tempest with a Fury wing is one of my more attractive ideas, along with the Sea Fury torpedo fighter with a Tempest wing to allow for torpedo carriage.  I'm also going to make a start on the Lancaster/Linncoln/Shackleton mash up next year.

[The Wooksta!]

Love the Tempest-winged Sea Fury torpedo fighter idea. Looking forward to that!

BTW: assuming that I got the scaling about right, it is impressive how much more compact they got the Hornet cowlings compared with the Mossie originals!

The engines are smaller in cross section as RR removed all the ancilliaries and put them behind the engine. 

I've a two seat version of the Fury TF done but the single seater is nearing completion.  Hopefully, I'll have it done by tonight.

[kitnut617]

I've had a review of all the info I have and various peoples comments, and not being as grouchy as I have been, started to look at this a bit more constructively.

I've been basing all my calculations (and arguments) on the fact that the prop was to be 15 feet in diameter which I got out of the Putman's De Havilland since -- book, and not the Sharp/Bowyer book (see top pic below).  This was up until the side profile appeared, the only dimensional fact to be attributed to the Sabre Mosquito that I could find.

But now we have a wing span and length dimension to work with, which suggested that the scaled up Mossie was 1.2 times bigger and to make a 1/72 model of it I would need a 1/60th scale drawing (or model), which I now have.  I found that even though some things worked in the side view, they didn't work in the top view.  For instance there's no way a 15 foot diameter prop fits in the top view.  I started to do a lot of measuring of the 1/60th drawing with my 1/72 scale ruler and one thing I found was that the real Mosquito prop diameter in 1/60th measured out to a tad under 14 feet diameter in 1/72 scale.  I decided to overlay some of the Tempest parts I have which I was planning on using in this build, over the 1/60th drawing and found that the 1/72 Tempest prop measures out to ---- a tad under 14 scale feet.  This was quite interesting because now I'm thinking that the Putman book 'might' be wrong because re-reading the text it also says that the proposed Sabre Mosquito was to carry 18,000 lb bomb load.  Now I'm fairly certain the Sharp/Bowyer book says it was to carry 8,000 lbs, but I don't have my book at the moment because my bro has it (he's building the 1/24 Airfix Mossie at the moment) so I can't verify that.

The upshot is I decided to scale off the Sabre Mosquito profile using 14 feet as the prop diameter and guess what I found ----- an almost exact fit with the 1/60th drawing (second pic). The fin and rudder are the same but it looks like the tail will have to be extended a bit (3rd pic)

last pic is the difference between the 15 foot prop profile and the 14 foot prop one.

[The Wooksta!]

Ages ago, back in days of lore, you may recall that I mentioned that the Napier Dagger was considered as an engine.

Anyhoo, I found the reference.  The Sharp/Bower book "Mosquito", pages 32 and 33. Very little, except to say that studies based around two large Daggers or one Sabre were considered.

Now, I have a mould for a Dagger so I'm thinking about converting an Airfix Mosquito back to the prototype or a alternate early mk 1 but with the Daggers rather than the Merlins.  Should look really different.

[PR19_Kit]

Now, I have a mould for a Dagger so I'm thinking about converting an Airfix Mosquito back to the prototype or a alternate early mk 1 but with the Daggers rather than the Merlins.  Should look really different.

That should look excellent! 

Apophenia's drawing looks wholly believable, and I bet it sounded awesome. Can you build a sound unit into the model please? 

[The Wooksta!]

A quick dig through the Mosquito spares box yielded the smaller tailplanes and two Daggers.  I've a spare set of bits from the Paragon Mosquito prototype set but it's the later one for the Tamiya kit so I'll have to leave the aircraft with the longer nacelles.  No smaller wheels either but I've the spoked wheels anyway, so it's a kind of halfway house.

Wings and nacelles now glued together.

[Mossie]

If you wanted to go the whole hog with th retro look you could drop the mocked up turret in there too?