DH 102(J) PR Mk 1

[Caveman]

As dizzy's put a project place holder down, I thought I'd do the same. Another 3d print but the rest you'll have to guess from the thread title (might be fairly obvious though). 

I'm on hols at the moment so won't be able to start till the back end of the week. Life (TM) is a bit complicated for a bit after so progress is likely to be slow. I will have internet access at least though, so looking forwards to seeing what else is cooked up.

[kitnut617]

I'm guessing this, Joe Cherrie's model.

[Caveman]

I'm guessing this, Joe Cherrie's model.

[Caveman]

So beginning work on the first step of drawing this out - I've got to decide what I want to build! Yes a PR jet mosquito, but what does that look like? I've done a bit of searching about and I havent been able to find a set of drawings that I am completely happy with yet.

The below is from quite a neat set of drawings by Justo Miranda but I think that possibly the scale is somewhat off!



This one is from an issue of flypast (June 1991 apparently) and seems to make the jet mosquito look even bigger!



I've scaled them so that the canopy is the same size for both - I think it is a reasonable assumption that the canopy would be the same scale if not actually the same. This makes the jet mosquito look huge in comparison. From what I can tell it should only be < 1m longer (13.56m vs 14.24m) and <1m longer span (16.51m vs 17.37m)*. If I were to scale the drawings to appropriate lengths then I think the Jet mosquito would seem to have a tiny cockpit. So I'm probably going to have to mash together my own drawings before starting on the 3d CAD, before I can print, etc...

Bit of a question to the floor if I may: I am pondering the potential for a pressurised cockpit for a PR version - which I think would make sense, or maybe pressurised flying suits would be utilised? I dont think a standard mossie canopy would work on a pressurised cockpit. The vampire would have been an earlier project than this and it had a pressurised cockpit at the time (I think) and so I was wondering about using a vampire canopy, off-set a-la vixen. Does that seen like a reasonable thought process? Or should I keep the mosquito canopy in order to make the heritage more obvious?

So showing ignorance with the above question, as there were pressurised cockpit mosquitos... So I guess ill keep the original style canopy


*interesting to note that the Canberra, the IRL jet replacement for the Mosquito, is nearly 5m longer and 3m more span

[kitnut617]

Caveman, some drawings were discovered a few years ago of the DH.101, DH.102 and the jet version of the DH.102. Those sketches you've posted showing the Jet DH.102, looked to be more the size of the DH.101. I have a full set of drawings of the DH.101 which Tony Buttler gave me some years ago as I have a build in progress of it. I'm not going to post them here though.

After inserting the drawings into my AutoCad, I was able to determine some actually sizes of the DH.101. I reported my findings to Tony and he had them confirmed by someone else. For my efforts, Tony kindly added my name to the Acknowledgements section to his book called 'British Experimental Combat Aircraft of WW.II'. You can find the drawing I have starting on Page 49 in the book.

Here though FYI, is a comparison between the DH.98 (Mosquito) and the DH.101. The DH.101 worked out to be 1.2 times bigger. To use a DH.98 as a base, it would have to be 1:60 scale to create a DH.101. I did find the canopy to be the same size as the DH.101.



After the DH.101 was cancelled because of unavailability of the Sabre engines, De Havilland was instructed to use the RR Griffon engine instead. De Havilland then scaled down the DH.101 to suit the Griffon engines. It was still bigger than a DH.98 though and there is some subtle differences to the fuselage, it's not like a DH.98. I don't think it's much bigger though, maybe not as big as 1.1 times bigger.

There's a good sideview of the Griffon DH.102 in the above book on page 51.

HTHs

[Caveman]

Caveman, some drawings were discovered a few years ago of the DH.101, DH.102 and the jet version of the DH.102. Those sketches you've posted showing the Jet DH.102, looked to be more the size of the DH.101. I have a full set of drawings of the DH.101 which Tony Buttler gave me some years ago as I have a build in progress of it. I'm not going to post them here though.

After inserting the drawings into my AutoCad, I was able to determine some actually sizes of the DH.101. I reported my findings to Tony and he had them confirmed by someone else. For my efforts, Tony kindly added my name to the Acknowledgements section to his book called 'British Experimental Combat Aircraft of WW.II'. You can find the drawing I have starting on Page 49 in the book.

Hmm thats really interesting. The numbers for the Jet Mosquito I am quoting from Tony's "British Secret Projects, Bombers 1935 to 1950" on p200. The dimensions of the Sabre 101 are provided (p55) as 14.78m length and 20.12m span (p55). Do they tally with the numbers that you came up with?

[kitnut617]

Caveman, some drawings were discovered a few years ago of the DH.101, DH.102 and the jet version of the DH.102. Those sketches you've posted showing the Jet DH.102, looked to be more the size of the DH.101. I have a full set of drawings of the DH.101 which Tony Buttler gave me some years ago as I have a build in progress of it. I'm not going to post them here though.

After inserting the drawings into my AutoCad, I was able to determine some actually sizes of the DH.101. I reported my findings to Tony and he had them confirmed by someone else. For my efforts, Tony kindly added my name to the Acknowledgements section to his book called 'British Experimental Combat Aircraft of WW.II'. You can find the drawing I have starting on Page 49 in the book.

Hmm thats really interesting. The numbers for the Jet Mosquito I am quoting from Tony's "British Secret Projects, Bombers 1935 to 1950" on p200. The dimensions of the Sabre 101 are provided (p55) as 14.78m length and 20.12m span (p55). Do they tally with the numbers that you came up with?

No, the dimensions worked out to 15.09m length and 19.81m span. Tony mentions these were the 'recalculated' from the previously published sizes -----  In the Mosquito book by Sharp/Bowyer it gives the prop dimension as 15'-0", I found that wasn't the case, it was the same diameter as a Tempest prop, just under 14'-0". Once that was established, everything else fell into place. I realized then that the size was then 1.2 bigger and that worked out to 1:60 scale. 

I got hold of a reputable drawing of the DH.98 and scaled it to 1:60, I then checked the prop diameter, here you can see what happens when you place a Tempest prop onto the drawing. In the previous pic I posted I had scaled the drawing which Tony had published in an Air-Britain AeroMilitaria article after the DH drawings had been discovered, so it measured 14'-0" in 1/72 scale, from there measuring the sideview determined what the actual length was.

[kitnut617]

Another thing I discovered is that when you scale the DH.101 sideview to 1/72 scale, the engine nacelles are almost a dead ringer to the Tempest Mk.I cowling. Which then lent credence to what else I had discovered. You can see here I had scaled the prop to 15'-0", but even though the nacelle shape was the same, it was a little larger. Once I changed it to 14'-0" diameter, the Tempest cowling matched it totally.

[Caveman]

Caveman, some drawings were discovered a few years ago of the DH.101, DH.102 and the jet version of the DH.102. Those sketches you've posted showing the Jet DH.102, looked to be more the size of the DH.101. I have a full set of drawings of the DH.101 which Tony Buttler gave me some years ago as I have a build in progress of it. I'm not going to post them here though.

After inserting the drawings into my AutoCad, I was able to determine some actually sizes of the DH.101. I reported my findings to Tony and he had them confirmed by someone else. For my efforts, Tony kindly added my name to the Acknowledgements section to his book called 'British Experimental Combat Aircraft of WW.II'. You can find the drawing I have starting on Page 49 in the book.

Hmm thats really interesting. The numbers for the Jet Mosquito I am quoting from Tony's "British Secret Projects, Bombers 1935 to 1950" on p200. The dimensions of the Sabre 101 are provided (p55) as 14.78m length and 20.12m span (p55). Do they tally with the numbers that you came up with?

No, the dimensions worked out to 15.09m length and 19.81m span. Tony mentions these were the 'recalculated' from the previously published sizes -----  In the Mosquito book by Sharp/Bowyer it gives the prop dimension as 15'-0", I found that wasn't the case, it was the same diameter as a Tempest prop, just under 14'-0". Once that was established, everything else fell into place. I realized then that the size was then 1.2 bigger and that worked out to 1:60 scale. 

I got hold of a reputable drawing of the DH.98 and scaled it to 1:60, I then checked the prop diameter, here you can see what happens when you place a Tempest prop onto the drawing. In the previous pic I posted I had scaled the drawing which Tony had published in an Air-Britain AeroMilitaria article after the DH drawings had been discovered, so it measured 14'-0" in 1/72 scale, from there measuring the sideview determined what the actual length was.

I would say that the dimensions that you came up with are pretty much the same (within reasonable error bands) of those quoted - single digit percentage differences. So I think thats pretty impressive sleuthing work from some 3 views and a propeller diameter! 

In the 2020 revision of Tony's book he states:

"An undated de Havilland report, comparing the Jet Bomber with a version of the firm's twin-Napier Sabre bomber, gave the data [as I quoted above]. This report also declared that the jet propelled aircraft could be made considerably smaller and lighter that the conventionally engined aircraft..."

As an extra check, the Canberra's wing area is 89m2 for a gross weight of 20865kg and the quoted wing area for the Jet Mosquito is 44.87m2 for a gross weight of 10954kg - which is reasonably in proportion for a wing doing a similar job.

I think that is good enough for me to go with a smaller aircraft.

[kitnut617]

As I said further up, the DH.102 was a bit bigger than the DH.98 but not as much as 1.1 bigger. Calculating 13.56m (length of DH.98) by 1.05 times bigger though, you get very close to your 14.24m calculation. So I think you're on the right path there Caveman.

Anyway, I'm looking forward to the result that you come up with for you model this time ----

[Caveman]

So progress has been nil so far. Still hopeful of getting something done but struggling to get time to sit down and get to it.