Talk:Northrop T-38 Talon

message: In comparing the T-38A to another trainer with nearly identical weight and thrust, we have the following:
T-2 Buckeye Navy jet trainer:  Max take off weight 13,170 lbs, 2X J85 engines with 2950 lbs thrust each (dry thrust), thrust to weight = 0.448, rate of climb 6,200 fpm.  
 
T-38 supersonic jet trainer:  Max take off weight 12,093 lbs, 2X J85 engines with 2900 lbs thrust each (on afterburner), thrust to weight = 0.480, rate of climb 33,600 fpm. 
The only first order thoughts I had to explain this were lower T-38 drag and that maybe the higher speed of the T-38 was generating a lot more ram air effect and thus thrust.  Even then though, a 5.4X difference seemed pretty incredible.  
Sustained (not zoom) rate of climb is primarily determined by thrust to weight ratio.  The text "Airplane Aerodynamics and Performance" has some quite illuminating basic statements and graphs on the subject, such as first order effect of jet thrust vs speed.  The net thrust of jet engines actually want to drop approximately linearly with air speed.  The ram air effect partially offsets this, but still thrust is declining with speed.  So, higher climb speed and more ram air effect does not explain the 5X advantage of the T-38 at almost the same weight over the similarly engined T-2.  In fact, the T-38A with its early J-85’s has about 70% the dry thrust of those in the T-2, with thrust in afterburner nearly identical to the dry thrust in the later J-85’s in the T-2.   
So, looking carefully at this article I see a note that reports that although the Air Force has been reporting 33,600 fpm climb for the T-38A for decades, pilots report 6000 fpm (!) on military power. I confirmed this with a retired F-16 squadron commander friend of mine who reports about 6000 fpm in military power, and 10,000 fpm in afterburner (below 15,000 ft, slower above that).  The T-38A briefly held the jet climb to 30,000 feet record at about 3 minutes, so had an average of about 10,000 fpm on afterburner to 30,000 feet, probably with one crew member and a light fuel load.    
So, the T-38 real climb is almost identical to the 6,200 fpm climb rate of the T-2 (as it should be). If there is any validity at all to this very high reported climb rate, then it would seem to have to be initial zoom climb from a high speed start, and not initial climb rate at takeoff.  Since kinetic energy is proportional to the square of speed, the high speed of a T-38 going flat out near Mach 1 and then pulling up does have a lot of built up kinetic energy that can be ballistically traded for gravitational potential energy (altitude) in short order. 
It would seem that the sustained climb rate should be reported as 6000 fpm in mil power (a reference is already cited), and that if the 33,600 fpm is kept that should be reported as initial zoom climb rate.  The referencing on this is not as clear as we would normally like, but what we have now seems to be a very large error that needs correction. This kind of error is apparently rare with jet trainers, but appears common as a specsmanship technique with fighters, and has apparently leaked over to the T-38 since it is derived from the F-5. PhaseAcer (talk) 21:06, 8 November 2019 (UTC)
replies: text: I have located a second and more detailed reference on climb rate for tactical aircraft.  The well known aviation author Mike Spick, in "Modern Fighter Combat", page 49, reports these very high modern climb rates for fighters are typically initial zoom climb at sea level from a starting speed of Mach 0.9. It would seem that should be reported here, and for any of these tactical jets reporting climbs over about 20,000 feet/min.  This explains these very different rates for almost identical aircraft.  For example, the F-102 reports 13,000 fpm, with thrust to weight of 0.7.  The F-106, closely derived from the F-102 and also with thrust to weight of 0.7, reports 29,000 fpm.  PhaseAcer (talk) 23:39, 14 November 2019 (UTC)
thread_title: Exaggerated Rate of Climb

message: There's a T-38 mounted on a pedestal at the Moira NY American Legion. Coordinates are 44.825915, -74.535409.
http://www.tinfeathers.com/Museum/Airports/AL_Post_939/Brushton_NY.htm 2603:7081:C02:5700:437:7DF9:8069:9F83 (talk) 03:54, 26 July 2022 (UTC)
thread_title:  T-38 on display.