Project Dornier Do-17z2

[aleatorylamp]

Hello Ivan,
Yes, I suppose it wasn´t much of a hot ship... although when the designs for the Fafnir engine and the aircraft started out in 1937, it was probably quite good, but not in the second half of WW2. Anyway, it´s lucky for me and Smilo that you are looking into the performance side of things. The extra knowhow certainly helps out!

OK then, thanks a lot for the clarification on the two maximum speed contradictions:
a) The Kauz (little owl) was faster and that accounts for the 265 mph. As it is, this speed just came out in the "unwanted" peak.
b) I´ll try to get the 255 mph, which at the moment are at 16400 ft, down to 13200 ft.

I just did a test at 13200 ft with the current .air file, and it gives a maximum speed of 259.6 mph with 40.4 Hg and 1012 Hp.
A little reduction torque will correct this, and S.L. power and speed will become more correct as well.
Of course, the current 16400 ft reading will desirably also fall, as will the unwanted power peak.
Let´s see what happens!
-----------------------------------------------------------------
First Update: OK, here we are! It´s slowly getting better.
I increased Drag a little and then started reducing Torque bit by bit:

Zero Lift Drag: added +1, now at 75
Oswald factor: added +500, now at 6200
Torque: lowered -0.003 now at.453
New results: (MP readings are the same as before)

Sea level: 224.3 mph, 989 hp (specs say 217 mph and 1000 hp)
10200 ft: 255.8 mph, 1080 hp (critical altitude)
10800 ft: 257.9 mph, 1086 hp (unwanted peak is lower)
13200 ft: 255.6 mph, 998 hp (specs say 255 mph and 940 hp)
15000 ft: 253.0 mph, 927 hp
16400 ft: 250.4 mph, 874 hp
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Second Update: Further testing. I wonder if this is more correct. Torque is now lowered to .450

Sea level: 223.5 mph, 980 hp (specs say 217 mph and 1000 hp)
10200 ft: 255.0 mph, 1071 hp
10800 ft: 257.2 mph, 1077 hp (unwanted peak is lower still)
13200 ft: 255.2 mph, 990 hp (specs say 255 mph and 940 hp)
15000 ft: 252.5 mph, 919 hp
16400 ft: 249.9 mph, 869 hp

What is happening was to be expected, but strangely enough speed is not going down as much as the power.

a) In order to get more correct slower S.L. speed, power is 20 Hp below specification, but it´s still 6.5 mph fast
b) Max. 255 mph at 13200 ft is correct, although we need +50 Hp to get there.
c) The unwanted peak at 10800 ft is considerably lower, which is a relief.
d) Higher altitude power and speeds are expectedly poorer.
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So... I wonder if all this is of any use...

Cheers, and thanks for inspecting the results...
Aleatorylamp

 

[smilo]

hello Stephan,
please take this for what it is,
just my opinion....

first, as for the asymmetry issues,
i would say, don't make yourself crazy
worrying about them.
to be honest, most of us here wouldn't even notice.
you are already well aware
that the design of this aircraft is very complex.
compromises will need to be made
if the model is to be completed.
use your resources for something more important.
save those kinds of detail for a different build program.

as my wife once told me,
"stop pointing out the flaws in your projects.
i didn't know they were there until you showed me."

the same holds for the air file.
i appreciate your tenacity
trying to get it gnats ass accurate,
but, i remind you, it's for cfs1.
why bust your balls
over a few miles per hour
at a few hundred feet?
that is, unless you really want to.
in the end, it's your project
and it's up to you how much
you put into it or leave out.

again, it's just my opinion.
either way, my hat is off to you.

 

[aleatorylamp]

Hello Smilo,
Actually, I agree with you on both points, thanks!
The asymmeties in question aren´t clear enough for me to be able to do anything about them on the model, so I´ll let that be. Then, the FD performance difference was quite small, but the adjustments last night seem to have got it closer to what it should be, once the contradictory information was cleared up, so I´ll leave it as it is now. As you say, further effort here won´t make any difference.
I´ve just finished the inner wing and when engine nacelles and outer wings are ready, I´ll post another screenshot!
Cheers,
Aleatrylamp

 

[smilo]

how about if we say,
further effort here won't make a noticeable difference.
it may be splitting hairs,
but, i believe more to the point.

good luck with the nacelles.
they would appear to be quite a challenge.

as always, i look forward
to your progress report.

 

[Ivan]

Hello Aleatorylamp, Smilo,

I did a bit more reading about the Dornier 215 and now I am even less sure than I was before about what the performance actually was.
The Germans claimed over 500 KPH for the Do 215 which puts it well over 300 MPH.
Another cool thing is that the Do 215 not only had respectable performance, it didn't have the Nacelle / Flap interaction as the Do 17Z did.

Aleatorylamp,
As I stated earlier, although the performance conclusions I came to regarding the Dornier 17Z did not agree with your conclusions, that really doesn't mean my opinion is better than yours on the subject, especially as you probably have done much more reading than I have.
This is YOUR project, so build it any way you like.

I came across yet another surprising thing: The Dornier 215B-1 with the Gnome radials was getting almost 290 MPH which sys even less for the Brandenburg Motors radials.

One correction which is actually in my notes but I did not notice when making a prior post: The higher speed of the Do 17Z Kauz Night Fighter (not sure if it was a Z-7 or Z-10) made better speed and altitude but it was with BraMo 323R-2 engines and not the 323P-1s.

Still reading and making notes and still looking for the propeller pitch numbers....

- Ivan.

 

[aleatorylamp]

Hello Smilo,
Here´s another set of screenshots.
I´ve done the wing, and now come the nacelles.

Hello Ivan,
Yes, the 323-R-2 had water injection and was more powerful. They also used it on the FW Condor, I think.
Don´t worry about my misinterpreting your coments at all. This is a discussion, implying everyone has their say, and I know I don´t have to do what others say unless I think it´s good for my project! Anyway, you see that I can do some things that are suggested, but not all.
For the moment, it´s going quite well. We´ll se how it continues with the nacelles...

It´s a Do-17z2, and I may modify it later for the Do215 hot-rod, but we shall see!

I may also make the Do-17z10 night fighter, to take advantage of the build for an extra model.
It´s like more effort- efficient, isn´t it?

Cheers,
Aleatorylamp

 

[smilo]

the speed at which you build
never ceases to amaze me.
i'd still be back there,
cleaning up and scaling the drawings.

attached are some more texture options.
my apologies for the quality of the images.

 

[smilo]

oh, what the heck, one more.

 

[aleatorylamp]

Hello Smilo,
There´s certainly a chice as to colour schemes!
I´ve been busy with the nacelles, flaps and ther retractable rear nacelle parts, and it hasn´t been too easy. The flaps still cause bleeds, but it seems to work. Here are some shots.
For the moment, I´ll finish the tailplane now.
Cheers,
Aleatorylamp

 

[smilo]

yes, you have been busy.
she looks very good, Stephan.

four days from my comment
on the speed which you build.
to be honest,
i was beginning to worry.
i thought, maybe, the nacelles
had sent you running away,
screaming off a cliff.
or, you had taken a much deserved vacation.

anyway, it's nice to see the progress.
how is the resource count?

 

[aleatorylamp]

Hello Smilo,
Thanks for your support!
Ha ha! You are actually quite right about my problems with nacelles. I always find matching their upper and lower parts to the inner and outer wing sections extremely difficult.
Also, the tailplane being a shoulder wing, is not as straight forward as I´d thought - it has to match a small fuselage bulge there, but it´s coming along OK!
Parts count at 108% (864 out of 1200) is no problem, so I think I´ll have enough left for at least 3 or 4 crew and guns, although some of these planes had 6 guns (but only 4 crew).
Cheers,
Aleatorylamp

 

[Ivan]

Hello Aleatorylamp, Smilo,

Smilo is right, your speed in building is amazing.
With your project going and the recent revelation about the Dornier 215, I have been looking at LOTS of photographs of the Do 215B-4 and the Do 17Z-2.
Even though I am not working on my model, I can say that I would not even be done browsing pictures and you already have most of your aeroplane built.
....and that is after having done the photographic and drawing review once before!

I actually have been trying to work out a sequence for the rear of the Nacelle and the Flap interaction that can be done all within AF99, but it is very resource expensive. It would not be a problem with my model because the final assembly has to be done in SCASM, but it probably would not work on your version.

Regarding the Tail Cone et al., it seems like one of the more straightforward areas of the entire aeroplane, especially if you are not trying to animate the control surfaces. I haven't figured out a nice way of animating the Elevators without some bleeds, but the Rudders look pretty simple.

Regarding the armament: Although the gun count is pretty high at 6-7 in all, the arrangement is not terribly effective. I am not entirely sure yet now to best model that effect in a CFS DP file.

I have been doing some poking around at yet another potential project. (It is pretty easy to browse almost anywhere with a decent cell phone and lots of data available.) Would anyone be interested in yet another "Design Study" thread?

Take Care Guys.
- Ivan.

P.S. I do notice a minor issue with your model: The Dornier 17 had Split Flaps, not Plain Flaps.

 

[aleatorylamp]

Hello Ivan,
The tail empenage went OK despite my misgivings about the fuselage bulge there - I had to eliminate it anyway for parts-count reasons. Otherwise the crew and the weapons would fall short.

At the moment after some simple landing-gear struts, I´ve also put in a pilot and 3 machineguns. Now parts-count obviously rocketed up to 143.3%. In order to get in 6 or 7 machineguns, and have enough for some more crew members, I´ll have to take out a bulkhead from the machine-guns to simplify them - although then they will look like rifles...

Thanks about the split flaps - I had trouble trying to figure out what type they were. OK then. That has just saves some parts: Without the cut-out wing and the extra upper-flap surfaces it amounts to 10% parts!

Cheers,
Aleatorylamp

 

[aleatorylamp]

Hello folks,
The split flaps now work almost fine - when lowered completely the glue gluing them to the rear nacelle fails.
Then, there are now 3 crew and then also 2 nose guns, the upper of which is for the bomb aimer who sits next to the pilot, a dorsal one whose gunner is just a head, and a ventral gun in the belly canopy, and you can´t see the gunner.
Landing-gear struts don´t bleed, and with a parts count of now 148%, I think I just about have enough parts for the 3 wheel doors and wells, (the rear wheel was also retractable) and the thick antenna on the cabin.
Let´s see...

Update:
Now I´ve got everything in that I want, antenna included, and parts count is at a squeezed 149.9%!!
I had to duplicate the outer wheel-doors because of bleeds, and although it´s not perfect, it´s better.
Ivan: I wonder if it´s time to post the model incl. AFX (there are no main textures as yet) for you perusal, (of course, if you would be so good)?

Cheers,
Aleatorylamp

 

[aleatorylamp]

Hello Ivan,
I was going to answer before: You were asking > Would anyone be interested in yet another "Design Study" thread? <
I´d say "Yes indeed!", if you were up to it!

...and here are another 2 shots of the Do17-z2.

Smilo:
I think I´ll have to ask you to start deleting attached images from my few first models from 2 years ago, as I think my attachment-quota is slowly filling up. Unless of course there is a way I can do it myself without bothering you!

Cheers,
Aleatorylamp

 

[smilo]

there's an attachment-quota?
that's news to me.
i'll look into it.

 

[aleatorylamp]

Hello Smilo,

I think there´s a maximum Mb per person for attachments.
A couple of weeks ago there was a change made in the way of editing posts. The advanced editing mode which allowed editing titles and attachments was made to be standard, and only one mode is available now. During the day they were making the change a notice would come up stating how much of the maximum Mb per person for attachments I had used, and I think it was about 75%, but I´m not sure. Anyway, it´ll still be couple of months before it reaches the limit.

I´m putting camo textures on the Do-17 now!

Cheers,
Aleatorylamp

 

[smilo]

i have the capability, among other things,
to edit posts and manage attachments.
which, by the way, i try not do.
(okay, i'll admit to correcting a typo or two)

i did look into it and found...
when clicking on Edit Post,
then, Manage Attachments
i can delete them.
i'm just not sure if by doing so,
the attachment is deleted
just from my view or everyone's.
to be honest, i'm adverse
to deleting your attachments.
i guess i'm afraid of deleting something important.
as i see it, it's your call.

here's how to do it;
in the upper right corner,
click on Settings, then,scroll down the menu on the left
and click on Attachments
all your attachments are listed
with a check box to the right of each.
after selecting which you want to delete,
scroll down to the bottom
and click on the Delete Selected box.
that's it, you're done.

i would highly recommend taking your time.
as i said above,
there may be something important.

now, back to the task at hand...
i anxiously await the next phase
of the Do17 project.

 

[aleatorylamp]

Hello Smilo,
OK thanks, I found it! - as I´m only a little above half the maximum, I won´t go about deleting anything for another year or so!

At the moment I´m fitting the Dornier 17 camo textures, and as soon as their edges match, I´ll post some pics.

For the event you are itching to try it out, I´ll also post the model when the textures are acceptable! (For the moment, only camo colours with no markings). That way you can have a closer look.

The model is the 5K-U, whose picture is in the middle of the three you sent, with yellow rudders and forward engine nacelles.
I like the nose-art eagle it has!

Cheers,
Aleatorylamp

 

[smilo]

YES, SIR!
please send me a beta model.
i would be honored to check her out.
i'll give her the once, twice, thrice over,
even though i am adverse to nitpicking.

i agree regarding the U5BH scheme.
i, too, like the yellow accents and eagle nose art.
yes, we disagree on the numbers/letters.
may i direct your attention to post #14?
same image, but, much sharper.

i also agree that you should hold off
deleting attachments.
what's the rush?
maybe, when you get around 90%