By STAN KASPRZYK

FlightLog Archive

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Aircraft Flown

Climb Performance - Jan 2022

I recently had my propellor overhauled and re-pitched on my Piper Warrior, to get to spec static RPM performance with my new 161 HP O-320 engine, and also for a bit better climb performance. My normal references at Renton - passing abeam tower on climbout and altitude at the end of the runway - were both improved while climbing out near Vx, the best angle-of-climb speed. Abeam tower with the new prop, I was at about 400 feet AGL, and climbed to around 700 feet AGL by the end of the runway. Not bad for a family cruiser.

I next had a fun demonstration of climb performance in my friend Eric's Super Cub with STOL (Short Take Off and Landing) mods and a 180HP O-360 engine, in other words a more powerful engine than my family model, combined with a lighter weight airframe and a wing optimized for climbing over cruising. Eric suggested around 60 MPH for the climbout, which is probably closer to Vy, the best rate-of-climb speed. Vy is slightly faster than Vx, but gives better cooling in many engine configurations. Since I had just flown my Warrior the day before, I used the same tower and end of runway points for comparison. Wow, it felt like I levitated off the ground after takeoff in the Super Cub, attaining about 800 feet AGL when abeam the tower, and nearly 1500 feet by the end of the runway. Very nice!

In any complete discussion of climbing performance, my previous experience flying the F-15 Eagle needs to be included. A fine example of impressive climb performance occurred while picking up an F-15 from Robbins AFB in Warner-Robbins, GA, after depot-level maintenance. The F-15 was in a rare configuration - completely clean of external fuel tanks, with both wing and centerline pylons removed. I took off on a cool February morning, with temperatures in the mid-40s - perfect for robust engine thrust and good climb performance. The local crew chiefs had mentioned that the local Eagle maintenance check pilots rarely flew full afterburner takeoffs, and since I only had a short flight back to Eglin AFB in Florida, I requested and was cleared by tower for an unrestricted climb to Flight Level 410.

My recollection of comm with ATC gives a pretty good assessment of the climb performance:
"Robins tower, Steely 11 is number 1 for runway 33, unrestricted takeoff."
--"Steely 11, you are cleared for takeoff on runway 33, unrestricted to Flight Level 410".
"Steely 11 copies, cleared for takeoff runway 33, unrestricted to Flight Level 410."

We rarely used or needed afterburner with our normal centerline tank configuration, so this totally clean Eagle accelerated quite well when I plugged in full burners and started rolling down runway 33, getting airborne very quickly. I leveled off at 100 feet to accelerate...300 knots...400 knots, approaching 500 knots I started a smooth pull to the vertical...

--"Steely 11, contact Atlanta Departure on 279.6...standby...say altitude passing".
"Steely 11 is passing 17,000."
--"Wow...ah...Steely 11, now contact Atlanta on...say again altitude passing...".
"Steely 11 is passing Flight Level 300."
--"Roger, Steely 11...ah...just go to Atlanta Center High now on 360.5".

"Atlanta Center, Steely 11 is with you, leveling at Flight Level 410".
--"Steely 11, roger, our radar is still catching up with your climb rate, pretty impressive."
Impressive indeed, as I looked down while rolling out on course to Eglin at FL 410...and I hadn't even reached the end of the Robins AFB runway 33 yet! Now that's climb performance!