Sync Gear: How World War I Fighters Avoided Damaging Their Own Propellers
hartzellprop.com
hartzellprop.com
Sidenote, I'm sure they took all the needed safety precautions but it sure seemed like they were standing in front of the gun barrel in a few shots which made me super anxious. I knew nothing was going to happen (since it was posted on YouTube) but it just felt felt dangerous.
no they didn't, one of the most prominent advocates working on this problem was killed by a ricochet. let me see if I can find it...
I’d be interesting to hear more about the advocate you’re talking about, early-in-field professionals are so often fascinating.
See this excellent Twitter thread if you want to know more about the mechanical properties of both designs: https://nitter.42l.fr/F22124509/status/1538990570684784645#m
[1]: a pusher propeller is behind the plane, “pushing” it instead of the more common “puller propeller” located in front. For examples of pusher propeller designs, look at popular UCAVs out there, like MQ-9 Reaper and Bayraktar TB2.
But as you say, the puller turned out to be superior.
as an example problem in statistics class in grad school, we showed that the intuition that maneuverability is most important in a dogfight is incorrect, that it's speed (fly in, take a few shots, zoom away, lather rinse repeat) and that's why WWII fighters were so designed
of course, all else being equal, maneuverability is good, but all else is not equal, there are aerodynamic tradeoffs
I'd be curious to learn more about your statistics example though.
The point of these exercises was to learn to focus on the data statistically/analytically and not by eyeballing presentations, and the obscuring/revealing of the truth was to drive home the point that "lives can depend on this".
He'd approach the circle, a bit above it, then dive. He'd pull up towards an airplane on the rim of the circle. Right when his Messerschmitt would stall, he'd be in perfect position to fire into the cockpit of the British pilot, and then fall away. Nobody could follow him.
Doing this successfully required a complete mastery of the airplane. Stall too early, and you won't get a shot in. Stall too late, and you fly right in front of the guns of your opponents. Nobody else was able to make this work, and many died trying.
He racked up 158 kills. He died when his machine suffered engine failure and he bailed out, only to hit the tailplane.
https://en.wikipedia.org/wiki/Hans-Joachim_Marseille
Although a movie was made of his career, The Star of Afrika, it isn't very good.
E: perhaps reading your linked thread before making this comment would’ve been wise of me :)
Animation of a mechanical link system: https://www.youtube.com/watch?v=j1OxWxYAGlc
Hydraulic: https://www.youtube.com/watch?v=8Oh1pLl1--Y
I've always assumed there was a reason for it that required solving the engineering problem in the first place. But now I wonder whether it was just simply easier to invent the 'sync gear' than deal with whatever problems ensue from moving the guns.
> Sync gear, also known as an interrupter or gun synchronizer, was developed during World War I to ensure that...
Was the sync gear an application or adaptation of an existing technique?
focal point: not sure if its the right term here, what I mean is: If you put the guns far to the side and still let them shoot straight you have drastically reduced the chance to hit a plane flying in front. And if you point them inwards you have only one good distance (where bullets cross, like focal point) where you hit well.
Guns mounted on the wings had to be canted inward so that their pattern of fire intersects at some distance in front of the aircraft, so you only get the full firepower of all your guns at or around that specific range.
You can mount guns in the wing, as seen on many WWII fighters, or run through the center of propeller shaft. These approaches have significant benefits, notably the rate of fire is not limited by propeller speed and number of blades, as well as having much more room to work with when wing-mounting (or the case of the P-39/P-63, having significant volume in the nose).
However, these approaches have some significant limitations, particularly for WWI-era aircraft. Most importantly, the wings of WWI aircraft were not strong enough to survive the stresses of mounting (and firing) machine guns. Wings of WWII and later metal aircraft are vastly stronger than the early wood, fabric, and wire bracing wings of most WWI aircraft. Through-propeller mountings are fundamentally incompatible with radial and rotary engines, and really only work with V-type inline engines. Relatively few WWI fighters were fitted with such engines. Also notable, wing-mounted guns must be angled inwards to converge at a desired range, and to be effective a pilot wants a gunsight that helps them estimate range to target. Such gunsights didn't exist in WWI, and so fuselage-mounted guns are easier to aim with basic sights.
Some did do just that.
With the British Foster mounting[0] variants of the S.E.5a, Sopwith Camel and Nieuport fighters mounted their guns over-wing and above the arc of the propeller. Convergence issues still apply here, as noted by the other comments.