Help, Dornier Do 17E/M/P engine location - are they the same?

[Icabod]

I have plans for the Do 17E/F and the later Do 17M/P. The E/F plans have the engines positioned inboard of the M/P plans. The M/P plans have the engines in the same wing location as the Do 17Z. This suggests that the engines were moved outboard when they were changed from the inline BMWs to the radial BMW 132s. It seems unlikely considering the wing construction but the plans look good. Moving the engine position outward isn't mentioned in anything I have read.

[KRK4m]

That's true. Also the German-built Do 17Ks for Yugoslavia (Kb-1 bomber and Ka-2 recce-plane, both with fabric-covered wing undersurfaces) featured engines close to the fuselage, while later series (licence-built Ka-3 with metal-clad wings) had them moved roughly 10" (250 mm to be exact) outwards.

[Test Graham]

The requisite propeller diameters might be a hint, if that is known. The aircraft will have been designed for the less powerful inline BMW VIs, whereas the more powerful Bramos would need a larger prop requiring a wing rebuild to move the engines further out. The wing will have undergone a redesign anyway when moving from a fabric-covered structure where all loads are carried by the internal structure, to the later stress-skinned design where some of the loads are carried by the skinning. It would seem an ideal opportunity to do the two redesigns as one.

[Icabod]

Ahh.. at least the plans I have are likely to be correct. The problem is the Hobbycraft Do 17E model has no moulded nacelles on the wings, unlike the Do 17M/P or Do 17Z. When the wings are marked with the correct locations the engine nacelles do not fit at all and where they do fit, the engines point down about 10 degrees.

All the web reviews concentrate on the banana fuselage which is fairly simple to fix, but none mentioned the engine locations and the major surgery needed to make the kit engines fit. I must say though that the overall dimensions appear to the be almost spot on and I have already fitted 8swg piano wire strengthers in the rear fuselage and across the wings to keep them square to sort out the warps, now I'll press on and get the carving knife out.

Thanks for the confirmation, it's appreciated.

[Pawel Burchard]

regards,

Pawel

edit - and here for Do 17 P

Edited April 29, 2014 by Pawel Burchard

[Test Graham]

Thanks Pawel: It's good to find that the logical solution actually turns out to be the right one!

[KRK4m]

So I have to apologize - not "roughly 10 in", but "almost 8 in" (200mm and not 250 to be exact), although the blade of propeller fitted to BMW 132 engines (17P) is 250mm longer than corresponding blade of BMW VI 7.3 (Do 17E/F) prop. The Bramo 323 (17M/Z) prop blades are 200mm longer than those of BMW VI and 50mm shorter than those of BMW 132-engined variant.

[Denford]

Very interesting, and not strictly the thread of engine position, but note the smoothly curved junction between the fuselage underside and the wing.

At Cosford I spoke with the Airfix designer who had 'created' their forthcoming Do 17Z. I asked him if he examined the wreckage (yes) and asked if it had influenced their product. Yes, the junction between the fuselage and wing was much sharper than shown in 'plans' and he had amended the design accordingly!

This goes to show what some know (but many, many others do not), don't ever trust plans, even those from the manufacturer!

[Icabod]

The drawings are very helpful for this project, thank you Pawel. I have already made a start using the plans I have. It will be interesting to see if I have got it right. Back in UK next weekend hopefully. I'll check then.

[tempestfan]

Have you checked the German "Vom Original zum Modell" publication ? It's been some years since I had a look in mine, but the Do 17 volume is one of the better ones in the series, and IIRC it contains a number of reprints of manufacturer's dimensioned drawings (which may not work as scale ddrawings but give some additional dimensions and/or details).

[Icabod]

Yes, I have the Do 17 book. It is very helpful but the 3 view drawing are undimensioned. I did scale one of its drawings using a dividers and ratios but I could not be certain the 3 views were scaled anyway. Now I am back home I have checked the work done so far and found the 'guesstimates' I used have given me a distance of 101mm. Distance should have been 104mm. This puts the engines out by 1.5mm each. Technically wrong but they do look right. When I figure out how to post a picture I'll put it on the posts and start a build article. After the debacle of my first build of this model a lot of years ago, I would like to get this one looking right, externally at least.

Edited May 10, 2014 by Icabod