I’ve seen some airplanes that have a long narrow spike sticking out of the front of the plane. What purpose do these spikes serve? I assume they’re not for air jousting.
A few examples:
Dornier DO-31
Grumman F9F-4 Panther
Hawker P-1127
North American F-100A Super Sabre
Republic F-105 Thunderchief
Isn’t that where the Pitot tube is?
Some of those look like a Pitot Tube used to measure air velocity.
Another looks like it has an antenna hanging off of it.
At another site (that I just lost the link to and cannot find again dang it) it was suggested you stick them out on a spike like this to be able to take readings unaffected by airflow around the plane. For instance jetliners have a pitot tube sticking out of the fuselage just a little bit but presumably this can be affected by airflow around the plane. I presume they account for whatever effect that may have today but perhaps in all those older planes they felt they needed to stick them way out in front.
It’s used when jousting with other aircraft…
NM…too slow…already answered. I think the jousting thing has possibilities though…
-XT
Donut holes.
Apart from jousting, sometimes aircraft have a big ass spike for refueling.
There may have been a need to put the pitot tube out there, but the Super Sabre looks like the spike is meant to alter the air flow conditions at the intake above it. Some of the other planes may have used the spike so that the overall nose shape was fairly blunt at low speeds, and pointed at high speeds to reduce profile drag.
But why would they make a pitot tube eight feet long? Most planes get by with one on the side of the fuselage, a few inches from the body and a few inches long.
If you have a longer pole then…um…well, it makes it easier to knock the other guy off his plane! Yeah…that’s it…
-XT
Aircraft in flight test will often be fitted with a super-long pitot tube, which will give more accurate readings than a compact one that can be disturbed by local air flow, but which are fine for normal flying.
It looks to me that the F9F, F-100, and F-105 spikes are pitot tubes. (The F9F is not a -4 but a mod -6 or later, the swept-wing Cougar rather than the straight wing Panther.)
On the other two craft, they are probably pitot tubes PLUS other equipment for use during testing. The P-1127 does not have those particular tubes on production models and that version of the DO-31 was a test bed.
To add to that, the reason they don’t need the highly-detailed info in the production models is because they already got the highly-detailed info when they were testing the plane and seeing what it could do. The prescribed performance limitations (do not exceed such-and-such speed and such-and-such altitude and such-and-such angle of bank and so on so forth) are based around that data, so they can have a margin of error when using a somewhat less-accurate-but-still-good-enough pitot tube that might simply take up less space or be easier not to break off, or might simply be moved to make room for other equipment they wouldn’t be carrying in the test version, such as radar or communications equipment.
And also as said before, sometimes when you see a long tube sticking out of the front of an airplane (and especially when you see it sticking out of the front of a helicopter), it’s for aerial refueling. The tanker strings out a fuel hose with a basket on the end that looks like a giant badminton birdie thing, the tube connects to the nozzle inside the basket, and they get gassed up.
Of course, 99% of the time, it’s mainly for jousting. 
I suppose a big spike would also be useful is the pilot wanted to harpoon a few geese for his supper.
It does provide a handy bit of motivation for the geese to get out of the way. You’ll note that Airbuses don’t have spikes on them, and we all know how THAT ended.
Pitot tubes may be longer than usual on supersonic aircraft, to get it out ahead of the main shockwave from the fuselage.
On the hun, I think its a radio antenna.
Declan
A pitot tube mounted far forward in clean air may also be used during test flights to calibrate one that is mounted close to the fuselage, where the local slipstream velocity may be different (due to interactions with the airframe). A calibration curve can be developed this way, so that when the close-mounted pitot reads X local slipstream velocity, they know the aircraft is actually traveling at Y knots.
I think it has to do with the shockwave that develops at high speeds. It’s designed to push the shockwave ahead of the plane and help minimize it’s interaction with the wings. I know I’m describing it poorly - but I’m pretty sure it deals with moving the shockwave ahead of where it would otherwise develop.
This shows some graphic examples of different shapes.
Except that three of the five aircraft listed in the OP are subsonic; no shockwave would form at the nose spike.
This.
Nowadays long pitot probes are used only in flight test. Once enough flight test data is gathered to accurately calibrate the smaller probes close to the fuselage, they dispense with the long probe.
Most of the aircraft the OP mentioned were very early supersonics, i.e. 1950s designs. In those days airspeed indicators were little more than mechanical differential pressure meters and could not deal with the complex changes in pressure vs airspeed in supersonic flow around a large fuselage. So they had to use the long probe to get clean pressure values into the dirt simple meter.
Starting in the late '60s serious aircraft started having an “Air Data Computer” (ADC) Air data computer - Wikipedia to convert the physical pressure signals into electical signals to drive the cockpit instruments.
The wiki article is accurate for 21st century airplanes, but understates the history of these things. Simple ADCs using mechanical linkages, resistors, and capacitors were used in the '60s - '80s. Nowadays it’s solid state pressure transducers providing inputs to a digital computer.
Big airplanes also have a backup airspeed indicator which bypasses all the electronic mumbo-jumbo & relies on direct pressure measurements. That way if all else fails we have some speed indication. It’s common to see 10 or 20 knots difference between that indicator & the main ones at high speed. This is directly due to the standby indicator’s minimal compensation for local airflow around the pitot tube(s).
