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"difference between albatross dv and dva ?" Topic


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wardog17 Jun 2010 12:30 p.m. PST

what are the differences visually between the albatross dv and dva

Personal logo Dervel Supporting Member of TMP Fezian17 Jun 2010 12:38 p.m. PST

The structure was supposed to have been beefed up due to the lower wing failures reported on the D.V.

A clip from the net:
On 24 July 1917, Idflieg admitted that the D.V could be considered only as a lightened D.III of virtually equal performance: production was consequently halted after about 900 aircraft had been ordered and the model superseded by the D.Va.
The D.Va started to arrive at the front in October 1917. It was similar to the D.V but the whole structure was beefed-up with additional fuselage ribs, stronger wing spars and heavier ribs. Aileron control cables were routed through the lower wings as per the D.III and wing tip support cables were also fitted for additional strength (the only way of identifying a D.Va from a D.V). As a result, the aircraft was heavier than even the D.III and its reputation was only partly salvaged by engine developments giving more power.
The wing failures continued to occur and testing continued in an effort to resolve the problem. As a result of these tests, the aircraft were modified in-the-field by replacing the spar attachments, increasing the diameter of the drag and anti-lift cables and reinforcing the wing ribs at the point where the auxiliary bracing strut was fitted to the leading edge of the wings; all of which seemed to resolve the problem.

Personal logo Dom Skelton Sponsoring Member of TMP17 Jun 2010 1:03 p.m. PST

Ditto – the only way I can tell the difference in photos is the aileron horns.

show some respect for women Inactive Member17 Jun 2010 4:25 p.m. PST

This is discussed at length in my Yanks! book. I don't have these files handy -- will look at them tomorrow.

Just off the cuff, the Albatros D.5 did not have external support wires which reduced drag when compared to the D.3. IIRC this may have enhanced speed marginally but adversely affected maneuverability.

So they went back to external bracing wires which didn't really affect the speed of the aircraft (which was much lighter than the D.3) but did enhance maneuverability -- again marginally so.

The problem with the lower wing oscillations / collapse found in the Albatros D.3 persisted in the D.5 and D5a. so they put in a 'support bracket' located at the bottom of the Vee strutts to address the wing collapse problems (generally occurring in a prolonged dive). It is my understanding that this support bracket did little if anything to correct the problem.

There is a lot of confusion among some relating to the German Albataros D.3 and the Oeffag Albatros D.3 (which was the Austro-Hungarian version).

Dervel, where are you getting your information? I'd be interested to look at it.

mjc

Personal logo Dervel Supporting Member of TMP Fezian17 Jun 2010 5:09 p.m. PST

Wotan's Children website was were I picked up the clip.

link

I cannot confirm the total accuracy related to the weights, just that the DVa was meant to improve the lower wing failures.

gweirda Supporting Member of TMP Inactive Member17 Jun 2010 6:29 p.m. PST

on the side, this is an interesting write-up concerning the flutter… link

Old Slow Trot18 Jun 2010 5:37 a.m. PST

Also,I think the lower parts of the cabane struts were reinforced on the D5a to prevent that fluttering and to strengthen said struts.

Daffy Doug Inactive Member18 Jun 2010 8:41 a.m. PST

Just off the cuff, the Albatros D.5 did not have external support wires …
The D5 didn't have external bracing wires? I've never heard that before. picture Looks like bracing wires to me. In the pic link, you can see the "sheath" on the aileron control cable, identifying this as a D5 and not a D5a.

Hans von Hippel survived the loss of a lower wing in his D5 precisely because the control wires went through the top wing and not the bottom on a D5….

RockyRusso Inactive Member18 Jun 2010 11:40 a.m. PST

Hi

The problem involved the internal structure of the wing cellue where the center of spar rotation was not congruent with the center of lift of the section and the pitch momment of the section at speed.

Oddly the austrian versions didn't have the same problem because they recognized it and changed the placement of the central spar and added sub spars.

Rocky

show some respect for women Inactive Member18 Jun 2010 1:17 p.m. PST

Alright,

Here's the straight scoop:

Engine. While the 220 hp Mercedes and 200 hp Benz engines were used experimentally, essentially ALL D.3, D.5 and D5a aircraft were equipped with the very same 160 hp Mercedes engine -- allegedly the compression ratio was increased on this engine sometime in 1917 which raised hp to 180hp -- regardless this same engine was found in all three models.

D-5 Wings, interplane strutts and tail were identical to the D.3. The aileron cable configuration differed in that it passed through the top wing and had small shrouds while the D.3's ran through he lower wing and thence up to the crank levers on the top wing. the D.5 fuselage was 'flattened' compared to the D.3 most noticeable on the sides. The D.5 cross section was oval in cross section and deeper so that there was a smaller gap between it and the top plane. A faired head rest was fitted but it was frequently removed. The undercarriage was of the steel tube type with a fairing over the axle which provided extra lift.

The D5a differed in that the aileron cables were the same as the D.3. It's airframe was strengthened, adding 80 pounds of weight (1580 lbs v. 1500 lbs). It's head rest was also often removed. Later a bracket was installed to re-enforce the 'V' strut on each side.

As far as I can tell German Albatros aircraft wing composition was not altered significantly from the D.3 to the D5a.

Wing collapse problems persisted (generally brought on by a prolonged dive) in all models noted above.

Note, tail assemblies on aircraft built at the O.A.W. factory were different from the 'standard' tail assembly.

It was the Austrian (Oeffag) aircraft that had all the wing modifications.

Want to check it out yourself:

See:

Lamberton, Fighter Aircraft of the First World War

Signal Publications, Albatros Fighters in Action #46

Morrow, German Air Power in World War I, pp 36-72 & 80-112

mjc

RockyRusso Inactive Member20 Jun 2010 9:21 a.m. PST

Hi

quid, the change in head design for the engine and upgrading in horsepower wasn't "alleged".

Although, the way horsepower was rated is the same as we do it now. AND it doesn't actually compare to similar horsepower ratings for rotaries OR allied motors.

Throw in the issue that propellers were fixed and that was a compromise. Some were flatter pitch for better acceleration/climb, some were more corse in pitch for higher speed.

Rocky

show some respect for women Inactive Member15 Jul 2010 3:50 p.m. PST

So true Rocky.

That's why I stick to actual performance trials -- like a lot of things, you can argue about technical issues till you are blue in the face but the only thing that matters is the actual performance.

My choice of 'alleged' may have been poor. My thinking was two fold. First just because the Germans said they did something doesn't mean they did it. Second, either the increased hp did little for speed or none of the pilots noticed it (although the extra hp probably increased rates of climbs). It takes a great deal of power to overcome the drag of the design coupled with a relatively heavy aircraft.

mjc

RockyRusso Inactive Member17 Jul 2010 10:02 a.m. PST

Hi

I am hoping that your misunderstanding is another case of modern thinking rather than anything.

The issue of horsepower is that the propeller did not change. If you have the engine spinning at 1500 rpm, which is about where these engines turn, there will be no change in speed. They don't have variable pitch props and, in general, the allies used a more corase pitch prop optimized for top speed while the germans used a fine pitch optimized for "climb". Raising the HP means for the germans, that the motor reaches top RPM faster, and accelerates the plane faster when below maximum, but won't change the top speed.

Tests are problematical in that one cannot know how the conditions differed in the way the test was done.

To describe another era, the listed climb rate of the Zero doesn't reflect its energy advantage over its enemies, and the test of the Mc202 lists an amazing climb rate that did not show in combat (as well as a similar P51 climb test).

In the zeke's case, the test was from idle on deck to altitude from a carrier.

In the Mc202's case, the test was after unstick. In this particular case, the pilot to sell the plane, held it on along runway way past take off speed and only pulled off at about 190mph meaning that the first 1000feet was a 'zoom" climb not a actual climb test. Sold the airplane.

Similarly, the P51's first merlin test did something similar, and carried so little fuel that after reaching the altitude of the test, had to glide down dead stick!

So, In more recent times, rather than showmanship, governments hire actual aerodynamicists to calculate what the plane is capable of.

Rocky

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