zoomzoooie

Triflyer, What is the difference of the DII and DIIa? Can you confirm?

There is a lot of contradicting info on the Halberstadt D types on the internet.
I don't a copy of the Datafiles Halberstadt fighters yet but I have seen a lot of differences in the photos I have collected and the description of which type they say they are.

The differences I have noted from the photos I have:
Cabane struts - Early types have double inverted and others have a third inverted strut at the front. Others have 3 vertical cabanes.

Upper wings - Early types have straight trailing edges while others have an extented aileron cord and some of those have a taper at the center visiblity cut out. Some of those cut outs have straight lines and others are half round. These all had the trailing edge "droop". The later types had straight ailerons with aerodynamic aileron balances and no trailing edge "droop".

Aileron controls -The early types had cables coming for the lower wing to a horizontal aileron control arm. The cables exited the lower wing wide at the spar locations. There are some that the exit points on the lower wing where close together. The later types used torque tubes with control rods coming up near the fuselage.

Rudder - They all had full flying rudders. The early types had a sharp radius at the top of the rudder. The later types had a wider radius at the top of the rudder and some had the lower section of the rudder removed to allow a full elevator with out rudder allowance cut aways.

Elevator - They all had full flying elevators. The early types had rudder allowance cut aways.
The later types had the rudder allowance cut aways filled in.

Turlte deck - The early types had 7 stringers with fabric covering running part way to the tail. The later types had a plywood turtle deck that ran all the way back to the tail. These are the ones that had the full elevator, cut away lower rudder and aileron torque tubes.

Spinner - I have notice a spinner only on later types with torque tube aileron controls.

Engine - 120Hp Mercedes seems to be the most common.

From the info and limited pics I have I believe:
DII - straight wing trailing edge with "droop".
DIIa - extended aileron cord on the same wing and added front cabane strut?
DIII- extended aileron cord and taper near center visibility cutaway and vertical cabane struts.
DIV - I have no info but I would think that it would be close to the DIII. Maybe the center cutaway was rounded?
DV - Straight trailing edge,dynamic aileron balances, rounded visiblity cut away in upper wing.
DV later? - reshaped rudder with new strut brace location(some had no struts), full elevator, plywood turtle deck and spinner.

The fuselage was of wood frame, plywood and fabric. The cockpit forward had plywood covered sides and deck but I have a pic showing all fabric sides but it also has the 3 vertical cabane struts. The later types had a plywood turtle deck /all plywood?

Much of the drawings out there are contradicting, even on the same drawing. I compared the drawing to the pictures to arrive at my conclusions. I don't have accurate measurements but it seems it's agreed that the DII had a 28ft,10in wingspan. All the drawings do not show the trailing edge "droop".

I looked over the drawings from The Pipe's zipfile (thanks again).
I believe this is a DIII, not a DII as it is labeled. It show 9 turtledeck stringers when there should be 7.

ZZ