SE5a aileron cables and cabane rigging questions

Romani · 23 October 2007, 01:35 PM

I have been looking through many photographs of musems, both my own and those found in the web, and the cabane of the SE5a is a complex part and frustrating because it's obscured in wartime photos and is hard to get a good view of the area in museums.

I finally found a good photo wich hopefully illustrates my questions (click to enlarge)

So here they are:

1) Aileron control cables: The SE5a has 2 pairs of control cables, seems to me. On photos and the Roden box covers the one on the starboard side is easily visible, as well as on photos of the silver painted SE5a at the Science museum in London (sorry can't scan my copy now , so you will have to figure out) it goes into a neat hole in the cowling just next to the panel line, in this picture, you can see the opposite cable on the port side entering the machinegun cover

Now, there is another pair of wires in between the front cabane struts, i am not sure where exactly do they enter the fuselage but it seems the entry (or should be exit?) holes are higher than that of the ailerons.

Previously I had thought these cables were tranversal bracing wires, but now i realized every pair of ailerons should have its own pair of control cables.

2) What are those bulges on the wing? I had thought before they were the aileron control cables mechanism housing (what's the correct term? crank? pulley?) but now it seems the front control cables go inside the wing at the tip of the front cabane struts.

What are they? and what are those hooks projecting from them? In this picture it almost seems as the cabane bracing wire running from the base of the rear cabane strut to the top of the front cabane strut (wish i could draw this) is hooked to them, but on another picture I have this is not the case.

What are they for?

Bonus question:

What's the correct angle of incidence for the undercarriage axle wing?

In my photos of the examples at Hendon and the Science Museum, it seems is paralell to the fuselage bottom, however in this pic it seems to be angled downwards to be paralell to the ground and thus at an angle with the fuselage.

I am not asking for a precise measurement, just asking if it should be paralell to the body of the airplane or to the ground.

Breguet · 24 October 2007, 04:20 AM

I'd have to look more into the rigging questions. As for the bulges though aren't they to do with the gravity feed tank in the leading edge of the top centre section wing?

Breguet · 24 October 2007, 04:25 AM

As for the angle of the axel wing this should help

Breguet · 24 October 2007, 04:30 AM

This is the nearest I could fine to a drawing of aileron cables....

crankcase · 24 October 2007, 06:31 AM

romani
which museum is the photo you posted above? and is the model plane in front of the real one by any chance a hasegawa (or scratch-built)?

i find such models enhance the exhibit and are a good idea.
CC

FlyXwire · 24 October 2007, 07:57 AM

Romani,

The SE5a had a combination gravity fuel tank and radiator water expansion tank in the leading edge of the top wing's center section. The fuel tubing from the gravity tank ran down the port strut, while the water pipe from the header tank ran down the starboard strut. The tear-drop fairings on the underside of the top wing cover the drain-bowls/connections for these respective tanks.

On the aileron control cable circuit, here's an image assembly from wartime German and British documents showing the wing-enclosed routing of these wires:

The second series of RAF-wires from the top wing through the fuselage decking that you mentioned above (if I'm reading you correctly) are cross-bracing wires (listed as "M" in the British RAF-wire rigging diagram below):

Romani · 24 October 2007, 11:46 AM

Well, I try to avoid making "thank you" posts in order to not artificially pad my posting record, and because I get so wonderful replies in this forum from such wise people that I choose to let them close the thread so other people might feel curious and click on the answers, wich are far more interesting than my silly questions.

Some of my questions seem pretty obvious in retrospect. Obviously the axle wing should be paralell to the fuselage to offer less resistance in flight, though with the variations between axis of the airplane and axis of flight you can never be sure.

But since somebody asked a question, a big thank you to you all!

It seems now that in order to build some models you have to buy the bloody blueprints of the thing, and i thought going to a museum to take pictures would be enough

Oh well, research is half the fun!

Crankcase, it was taken in the Boeing museum, there are other pictures of the same museum in the Webshots gallery of the person that took them. No idea about the model, I just found it online in an image search, but usually the large scale models I see in museum are scratch built.

Flyxwire, thank you very much for your enlightening answer. I should have realized aileron cables can also run inside the wing. And I always had thought odd that there didn't seem to be cross bracing wires in the cabane.

Another question for you, you mention fuel tubing and water piping, but I can't see nothing on my museum pics, where they routed internally through the cabane strut or what? They must have been small pipes in diameter, because I can easily see the cable to the starboad interplane strut with the pitot tube (I think) on the SE5a at the Science Museum.

Bonus question: The machinegun is angled slightly upwards because the airplane was flown nose down, i suspect, but it's also angled slightly to the right of the gun as it seems in some photos? Twin machineguns are sometimes slightly angled toward the center for converging fire at a distance, just wondering if with guns offset to one side you have to adjust convergence too.

FlyXwire · 24 October 2007, 12:44 PM

Not silly questions at all Romani!!!

You are correct on the fuel and water lines running within the fairings of the front two cabane struts (if you have access to the Windsock Datafile Special on the SE5a, there's an excellent picture of both the cabanes and tubing on pg. 30).

As you know, the SE5a could mount both a ring and bead sight on the left for the Vickers, and an Aldis optical sight centrally, or to the right slightly. Although most MGs could be adjusted for convergence/alignment, I can only imagine that the Aldis sight picture reflected a generic view for both the Vickers and Lewis gun firing forward.

I've never seen any official WWI documents on bench-setting data for fixed aircraft MGs (other than photos showing this being done). Maybe someone else has more details they might be able to add to this subject Romani. (?)