100,000 Feet in a Canadian  CF-104 Starfighter   by Jim Reed

I flew the F-104 at Edwards and on exchange with the RCAF.  My most interesting F-104 time was while project manager/pilot for a world altitude record attempt with the RCAF. 

Using an F-104A with a B-model tail, stripped of unnecessary weight (e.g., most of the instruments), we would accelerate to Mach 2.5 while getting an energy boost from the jet stream, then pull up to a 60^o climb angle.  Going through 75,000 feet we shut down the engine and simply followed a ballistic arc -- the job of the pilot at that point was to keep the airplane pointy-end first.  The top of the arc was critical - If you pushed over too slowly the airplane would start down tail first, resulting in an uncontrollable pitch-up.  If you pushed over too fast, the engine's gyroscopic effect created yaw beyond your rudder authority and it would go into an uncontrollable flat spin.  (Even shut down, the engine was still turning at about 93% rpm.)

The descent was a mirror image of the ascent -- even without the engine you got to Mach 2+, restarted at about 35K' and returned to land, out-of-fuel.  Total flight time - 20 minutes.

Ultimately the limiting factors were total energy at pullup (kinetic+potential energy) and rudder authority at the top of the arc.

The nose boom from the aircraft is on a trophy in my living room; the rest of the airplane - RCAF # 700 - is in the National Air Museum at Rockcliffe, Ottawa, Ontario

At that time Russia had set the record at 103,XXX feet using rocket assist, but the rules changed and we couldn't use rocket assist.  National Aeronautics Association rules required exceeding the previous record by at least a minimum percentage so we had to get to 109,000 feet.

It wasn't aerodynamics, it was Newtonian physics -- total energy = kinetic energy + potential energy  -- potential energy is a function of altitude, kinetic energy is a function of velocity squared -- and velocity is groundspeed, not airspeed.  We made an assumption that our total energy would remain approximately constant -- that is, drag losses would be offset by having the engine running in a/b during the pull-up.  If sigma E (total energy) remains constant and you know the entry and minimum airspeeds, you can calculate the maximum altitude - "h", the only remaining unknown.  Essentially, you solve the equation, total energy at pullup = total energy at max altitude, or 1/2mv₁² + wh₁ = 1/2mv₂² + wh₂ .  v₁and h₁ are your entry conditions; v₂ is your velocity at the peak altitude, which can be approximated.  So the only unknown is h₂, the altitude at minimum speed.  Solve the equation for h₂ and you can select various v₁ and v₂ to see what your max altitude might be.  The velocity in the equation is with an earth-based reference, so having the jetstream as a tail wind adds to the total energy in the aircraft.  At peak altitude you don't have that additional velocity.  So the procedure is simply an exchange of kinetic energy for potential -- swapping groundspeed for altitude.  We don't usually llink flight characteristics with groundspeed, but in this case you're flying out of one airmass into another, using equations of energy, not aerodynamics.  Under ideal conditions, if our assumption was correct, max altitude was about 113,000 feet.

The F-104 is normally limited to Mach 2.0 by 3 factors -- directional stability, inlet shock wave and compressor inlet temperature.  By having an  "A" model airplane with a larger "B" model tail we calculated we had directional stability to Mach 2.5.  We got some special inlet duct nose cones from Lockheed that solved the shockwave problem, and we waivered the inlet temperature restriction.  We also increased afterburner fuel flow by 50%.  (We did overheat one engine, but only because the pilot didn't get it completely shut down during the pull-up.)

This was a Centennial Year project for the RCAF, so a Canadian had to make the final record attempt.  I got to about 103,000 feet during the workups.  There were 3 pilots -- me, Ron Hayman and Bud White (latter two are Canadians).  Based on the actual flight results we realized we could get to 103,000+, but not to 109,000', so we decided that as soon as the Canadian pilot (W/C Bud White) recorded an altitude over 100,000 feet we would end the program.  On Dec 6, 1967 Bud reached 100,110 feet.

Sidenotes: our only heading indicator was the whiskey compass, which was unreliable due to acceleration errors.  We navigated by observing our heading relative to the sun, and were consistently accurate within one degree.  Over the top, we showed 60-75 KIAS, -- and were still supersonic!

For other Aviation and Fighter terminology go to:  http://www.fighterpilots.net/glossary.htm