Albatros D II / D III news

[Koloman Mayrhofer]

hallo,

the incidence on the topwing of the D III DV and DVa is
according to the handbook of the polish airforce

centerline 4°
strut 3°
last rib 1,8
all on the right half
left it is 4.1° 3° 2°

bottom wings
5° 4,9° 4,2° right
5° 4,5° 4° left

this have to be treated with care as this are obviously taken from a particular example which was most likly rigged that way to fly straight.

the D II
has

[Koloman Mayrhofer]

hallo again
sorry was not finished with the post.

the D II
has
5,3° 4,8° 4,2° bottom

4,75° 3,78° 2,7° top wing

cheers
koloman mayrhofer

['14-'18aviationcollector]

Hi Koloman,

Thank you very much for posting this information. The slight discrepancies between Bob Waugh's drawings of the D.Va, Stanley Teachman's drawings of the D.II and the Polish report you have mentioned are very typical of discrepancies encountered when researching First World War aeroplanes. It is always very difficult to obtain definitive data when researching construction, covering and even doping / painting of WW1 aeroplanes. Although the Teachman drawings give the incidence of the top wing of the D.II at the centreline as 5 degrees, and the Polish handbook states 4.75 degrees, as you said, these differences could be due to measuring a specific example which has simply been rigged that way. As I mentioned yesterday I have seen first hand just how much you can bend a fuselage or manipulate a set of wings with some fine tuning of the rigging. The figure you quoted from the Polish handbook of 4 - 4.1 degrees for the top wing of the D.Va (whereas Bob Waugh's drawings state 5 degrees) make sense since I noticed that German biplanes often have incidence which converge at some point forward of the fuselage - in other words, the lower wings have more incidence than the top wing. I don't know if this was the case with British biplanes but I tend to think it was not. Your figures which are slightly different on each side also make sense to me since during my examination of the original Albatros D.Va I noticed that the right (starboard lower) wing panel has slightly more washout than the left (port lower) wing panel. This was achieved by starting the washout one rib inboard on the right (starboard) lower wing than it starts on the left (port) lower wing panel. At the time I wondered whether this was due to the various fabric coverings and coats of dope which have been applied to the wing panels over the years, or whether the wing panels were specifically built that way. As I am sure that many of you will have noticed, when airframes are doped on numerous occasions, the dope tends to distort each component each time it is applied, and causes the framework to shrink where it is at all possible. Your data confirms that the wings were specially built to have different amounts of washout on each side, which is what I suspected, since when you look closely at the real thing, it certainly looks as though it was deliberately manufactured that way.

I purchased some American Oak today, since I have not been able to find any European Oak so far, but following a discussion with Brinesharks (again, just today - isn't that always the way!?), he has informed me that European Oak is available from Matthew's Timbers in Melbourne. He said it is old and has been weathered, but still I think it's worth a look. I have probably asked you before if American Oak is a suitable substitute for European Oak, and I am reasonably confident that it is a reasonable substitute. It is virtually identical in appearance, and I have been told that they are very closely related to each other. I also purchased some King William pine, since it has been suggested to me that it is or could be a reasonable substitute for Spruce. I have not checked this with CASA yet, and when I called them, at least their Melbourne branch was closed this afternoon due to the storms. Does anyone know anything about King William Pine? I am keen to learn about it. It looks like Western Red Cedar, but when you look closely the grain is very similar to that of spruce. Again, Brinesharks told me that White Pine is a suitable substitute for Spruce (Chris has told me that too) which is good because it is easily available here in Canberra. Does anyone know anything about Kiefer (or is it Keefer?) Pine. I am keen to learn about it too. Apparently it was used extensively by the Germans for longerons and spars.

Cheers Koloman, and as always it is a real pleasure to see the results of your hard work as well as research work such as the figures you have just quoted.

David.

[Koloman Mayrhofer]

hallo,

i am pretty sure that this figures are coming from a particular airplane as they do not make too much sense.
i have not yet done any drawing work on the albatros DVa so i can not say what the intended design figures was. it should be more by 4,5° at the centerline.

the datas for the D II are the figures indicated by the design of all parts. stanley teachman had used a profile originated from the C type planes in his D II drawings. we discussed this issue at that time as we both had serious doubts about this but he was not able to correct his drawings in this case due to his degrading health.
after much more research i know now that they used the same profile as on the D III and D Va or better they used the same profile on the D III D VA as on the D II . its the göttingen 171. slightly modified. albatros had give a few airfoils developed by themself to the göttigen institute for testing.


have to look a bit into the books about your questions regarding the wood types.

more soon, i have to catch the last train home.
cheers
koloman

[sheppo]

I would not use this timber for structural stuff on A/C...It has a reputation for splitting faster than a dog on cracker night!
It can also be quite "spongy" if that makes any sense?
White pine is Ok so long as you can get the right grain, ring etc

Chris

[wilhelm]

I remember reading an article in WWI Aero where a captured example was disected and most of the wood used was Fir and ash. Fir for the spars and ash for fuselage longerons. If I had a choice, I would not use white pine for any thing structural.

Willie

[sheppo]

Good point Willie ,I should probably be clearer by stating "white pine is Ok" so long as it is in the necessary dimensions to perform the same job as the original.
Where Fir was used, white pine or spruce would not automatically be sufficient in the same dimensions.
Im happy to trade a little weight in the Dva for a stronger fuselage. Without ammo or heavy guns to carry so theres a little room to move.

Chris

[wilhelm]

Exactly my view, you figure the weight you will save using a modern engine and dummy guns is about 400 lbs, the weight of using fir is minor.

Willie

[sheppo]

I plan to have the engine of very similar weight one way or another...C of G must still be maintained of course!

anything else makes the flight attitude "interesting"....

[wilhelm]

what engine do you plan to use.

Willie