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Natter Guidance System

Grif

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I'm not sure if this is the right place for this, and if it gets moved, fine, but since I need the info for a space-related project that I'm looking at...Does anyone know how the German Natter rocket fighter was kept going straight up in the launch phase? It was shot up a telegraph pole, but it wasn't just "arrow stability" model rocket style, as I recall reading that it had vanes in the main rocket exhaust, like the V2, but instead of being graphite, they were sheet metal filled with water for cooling! Was there an autopilot of some sort, or did the pilot have to keep it on the right, ie, straight up, heading?
Grif
 

Weasel Pilot

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Natter had a vertical launcher, but I'd describe it as a gantry rather than a "telephone pole." While the advertised guidance scheme was radio control to the vicinity of the target and then via the pilot to launch of the R4Ms, given the difficulties the Germans had with their SAM guidance schemes, I find it hard to believe that this system had been perfected for the Natter, especially within the system's abbreviated development cycle (Aug 44 to Apr 45). My bet is "guidance" was solely by the pilot from start to finish, so it went where he wanted. As true vertical flight is rather uncomfortable (you have the sensation of being past vertical) most pilots tend to fly at something less than 90 degrees straight up. My guess is had the thing truly gone operational you would have seen a slight "bunt" as the Natter climbed, as a result of this. question is, how would they have handled the maneuver at the top of climb. Natural thing to do is pull down, but a zero to slightly positive g bunt would be better from an energy conservation standpoint. Might depend on combat situation. Targets overhead could be engaged with the more comfortable pull whereas those further afield would necessitate the energy conserving bunt.

RE: "Water cooled graphite vanes" seems like, unless you've got a good flow of water you'd run into problems with water flashing to steam and the resulting expansion have "deleterious" effects on said vanes.
 

robunos

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Water cooled steel vanes is correct.

From 'German Secret Weapons: Blueprint for Mars', Brian Ford, 1969:-

"Right from the start, when tests began, there were problems. In spite of an initial acceleration of 2g or more, the craft left the upright launcher at a speed of only 30-40mph - far to slow to alolow the wing flaps to exert any aerodynamic effect.Clearly (as in the V-2),some exhaust deflectors in the jet stream were needed. But how could they be included and still make the proposition economically sound? The answer was simple, steel vanes were included, each one hollow and filled with cooling water. There was no circulating pump or protective mechanism, indeed, none was necessary. Admittedly, after some seconds they would begin to heat up, then as the water boiled away, they would eventually melt away in the rocket gases, but by then enough altitude had been reached for conventional controls to become effective.
So an entirely new, and very viable notion was introduced - disposable, temporary control surfaces"

also from 'Warplanes of the Third Reich', page 67:- "...and small water cooled control vanes were introduced in the rocket engine orifice, these having a life of approximately 30 seconds by which time enough speed had been attained to render the normal control surfaces fully effective..."

cheers,
Robin.
 

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