lostpianoplayer et al.
Shock cooling is more myth than fact.
What engine/prop are you running in your Harmon Rocket?
In my Bonanza (IO550b/3 bladed Blac Mac) I can prove it to you with the EDM 700 engine monitor. I generally cruise LOP but the same theory works ROP. I have shown a very experienced CFI and he just shook his head in disbelief...before walking away, and I strongly suspect, convincing himself he didn't
really see what he thought he saw.
What I do on descent is the following.
When I want to descend I poke the nose down for a desired rate of descent.
As speed builds up I wind back the rpm...eventually all the way back to min governing.
When that is not enough to keep the speed in the green (about 3000') I reach out and in one smooth motion pull the throttle back from wide open, where it has been since takeoff, to around 16in MP. In doing so I dramatically decrease the air available to the combustion chambers and this enrichens the mixture from about 30-40F LOP to 50F ROP. 50-80F ROP is the hottest place to run your engine from a CHT point of view.
When I do that all the EGT bar graphs in the engine monitor increase (richer mixture burns hotter when you start from LOP) and the rate at which the CHTs cool actually slows down...this is the bit the CFI couldn't get his head around...the CHTs cool slower but I am still on a high speed descent with the IAS at the top of the green arc but the throttle pulled out to just above gear warning horn. You can actually see them ticking down a degree at a time on descent and when I pull the throttle they almost stop ticking down...the rate of cooling visibly slows.
It's fast enough that it'll set off the shock cooling alarm in level flight, at full power, immediately after takeoff
I would be prepared to bet folding money the alarm sounding in this case is
not your
shock cooling alarm. It is more likely to be a high CHT alarm which may be set too low...what is that set at now? If it is set at less than 400F it is set too low. If your hottest cylinders see 360F just after takeoff that is no problem at all. Keep them at less than 380F in cruise...if you're running an injected Continental without GAMIjectors I strongly recommend fitting them.
On descent do as I do and if you're running ROP just lean the mixture enough to be around peak EGT. In this configuration, peak EGT and min RPM you can happily pull the throttle back with no fear of shock cooling anything because you will be effectively enrichening the mixture to around 50-80F ROP when you reduce throttle. You may find they are around 300-330F when you pull the throttle closed...they can't shock cool at this point because
they are already cool.
As you approach circuit ht pull the throttle back to 12-13in MP and carry that into the circuit. You will find even if you hit the circuit at 200kts, one 180 degree turn...upwind to downwind...say 45 degree AOB level turn with a little 'G' will have you down to flap speed without all the carryon you're experiencing now...and with really low RPM and low MP you will be effectively in stealth mode and the neighbours likely won't hear you at all.
With a little practice and thought you will be able to time it so you hit flap speed abeam the landing threshold and simply add flap in a constant turn onto final while leaving the power alone...once down to approach speed on final the prop will be on the fine pitch stop anyway and you can shove it up to full fine for a go around without it making any noise at all.
Top rudder in a steep turn?
Not unless you're flying something with massive torque, like a Spitfire, Mustang, Bearcat etc...or something with very strange aerodynamics. Neither case applicable here I think.