WW1 aircraft structure questions

[Buddy1998 2]

While going through the damage model file line by line, I noticed a few odd values which raised some questions in my mind. I'd like to cut the amount of time needed to research these questions by drawing on the experience of the people here in this forum. This would help me fine tune the DM and any help would be greatly appreciated.

 

1. Did all aircrafts more or less have the same type of cable material (a metal alloy)?

 

2. Generally speaking which engines were more likely to fail or catch fire due to bullet hits?

 

3. Which aircrafts had their pilots more exposed to bullet hits (including observer position)?

 

Buddy

[Bletchley 8]

While going through the damage model file line by line, I noticed a few odd values which raised some questions in my mind. I'd like to cut the amount of time needed to research these questions by drawing on the experience of the people here in this forum. This would help me fine tune the DM and any help would be greatly appreciated.

 

1. Did all aircrafts more or less have the same type of cable material (a metal alloy)?

 

2. Generally speaking which engines were more likely to fail or catch fire due to bullet hits?

 

3. Which aircrafts had their pilots more exposed to bullet hits (including observer position)?

 

Buddy

 

1. I don't know anything about German wire, but here is some data on British wire. Not sure if cable wire differed in metal content from the flying and landing wires. The RAF wire was a flying wire shaped to reduced drag.

 

2. Inline engines were generally more vulnerable, I think, to bullet hits than rotary engines as they were mostly water cooled and had the addition of a vulnerable radiator and cooling system.

 

3. I think they were all more or less equally vulnerable, with the exception of some very late war trench-strafers that may have had some degree of armour protection for the pilot and observer (but from below). Pusher types had the engine placed behind the pilot and observer, and this could protect the pilot and observer from behind to some extent.

 

If you search on the Aerodrome forum you will probably find more, but hope this helps.

 

Bletchley

 

Edit: I also have a table for "Bullivants airoplane cable" (same source), but for some reason it won't upload. Can PM if you want it.

 

Source of wire data: Air Board data for structure and stability calculations of aircraft (August 1917): National Archives DSIR 36/4828

Edited April 9, 2012 by Bletchley

[Wels 2]

Hello,

in the first era there was piano wire used, which originated in France. Then, like Bletchley said, some of the british planes were equipped with streamlined wires, while german and austro-hungarian used braided cables, i think after 1915 (piano, before)

Anyway some tests have shown that there were no real advantages, the piano and streamlined steel wires twisted and vibrated in flight, taking away some of the advantage, while the air flowed well around braided cables, since micro turbulences in the air around the slightly thicker bundles allow the air to stream past those micro swirls without much resistance. However, different manufacturers within one nation used all kinds of different wires for their machines, especially airships tried out all kinds of wires for the vibrating engine gondolas, and within the rigid framework. Thanks for posting those sheets !

 

Regarding engines i have seen a lot of bullet and crash damage on photos, but i do not know which would be mmore prone to failure.

Usually rotary engines lost almost a quarter of their performance after the first four hours of service, which is why they had to be thoroughly maintained, exchanging cylinders and pistons all the time.

On one hand some rotaries were known for still running, even after one or two cylinders being damaged - certainly no damage of cylinder housing; others are said to virtually disintegrate in mid-air, losing all their parts accelerating along the lines of centripetal forces. Others just blocked and jammed, often tearing the engine off the fuselage by the violent stop ..

There is a reason rotaries were never used again, after WW1.

Engine fires usually develop after a leaking fuel system, so in-line engines were as prone to that as rotaries or so it think. I also believe most fires started not by burning engines, but a holed fuel tank or shot off pipes (and maybe carburettors sppilling). Engines of the time mostly used air pressure applied to the tank, to force the fuel through the pipes. Imagine a holed fuel tank, with enough pressure to make the highly inflammable fuel being sprayed all over the fuselage, engine, and you; and then being ignited by igneous bullets, spark plugs or the bushes running over those bare metal surfaces for the rotary ignition system.

Just some thoughts, i really do not know this for sure -

 

Greetings,

Wels

 

P.S. And Happy Easter :)

Edited April 9, 2012 by Wels

[Buddy1998 2]

Thanks for the info Bletchley and please go ahead and PM the table to me. This will definately help me refine the DM.

 

EDIT: Wels, thanks for that explanation. I also found similar descriptions on the aerodynamics of the wires.

Edited April 9, 2012 by Buddy1998

[Bullethead 12]

I'd like to add a bit on the behavior of engines. In general, I think inline engines were more likely to fail and rotaries more likely to burn.

 

On the subject of failure, inline engines were more likely to be hit because they were bigger targets. A rotary is a thin disk, presenting its largest area to front and rear and very little to the sides. And that's all there is to it. An inline, OTOH, has about the same front/rear area, plus is even bigger to the sides. And then there's the cooling system, which adds another fairly large target area, although this varied considerably between engines. Hissos had the radiator on the front of the engine so it only added a little extra target area, and arguably made no difference because bullets hitting it would probably hit the engine itself anyway. OTOH, German radiators in the upper wing definitely added a lot of extra target area.

 

On the subject of fire, rotaries were by nature rather hazardous. If throttled by cutting ignition to some number of cylinders, the other cylinders were still receiving their mix of air and fuel and spewing it unburned out the exhaust valves along with the castor oil. This tended to keep the inside of the cowling dripping with a mix of oil and gasoline, just waiting for an excuse to ignite. Castor oil doesn't burn that well and gasoline evaporates quickly in high winds, so most of the time rotarties got away with this. However, it was not unknown for them to catch fire spontaneously, and some engines did this quite frequently. The Gnome 160 was so bad about this that the French dumped all planes designed for it, which is how the US ended up with all the N28s and why the otherwise very good MS-AI was only operational for a few weeks. Damage, of course, could make this situation much worse...

[Buddy1998 2]

Thanks again for this great info. So, here's what I'm planning to do so far:

 

-Lower all probabilities to hit each damage box to correspond with exposed surface area of aircraft.

(Vanilla DM had most all probabilities at 100%).

 

-Inline engines have a 20% greater chance to get hit than rotaries -

Thanks to Bletchley, Wels and Bullethead for the info.

 

-Lower the cable hit points on all aircraft to be more or less the same -

Thanks to Bletchley for the info on cable diameters and load strength.

 

-Fuel leaks will start when the fuel tank reaches 20% of its hit points and explode when 45% or more of its hit points are gone.

(vanilla is set to explode when all hit points are gone)

 

-Oil leaks will start when 20% of its hit points are gone and loose all its oil when 45% of it is destroyed.

(vanilla is set at 100% to destroy the oil reservoir)

 

Buddy