FlyingWrench
Join Date: Jul 2008
Location: Lost
Posts: 16
Nutloose
After reading your comment on the engine reving high I am trying to understand what you mean. Lycoming engine with constant speed propeller? This would have a propeller governor with low pitch stop setting? Adjusting the stop screw would in return adjust engine rpm by adjusting blade angle. If I am way off base of what you meant let me know.
I agree everything should be put into the tech logs along with talking to maint about it. Alot of times mechanics will have a better understanding of what prob is and will have a better starting point.
FlyingWrench
I know where you are coming from, but this was a fixed pitch prop..... Now I know what you are going to say, it is the prop then, so we tried another one of an identical aircraft that had no problem at all to no avail, we then sent the prop away for overhaul and had them reset the twist in the prop to the max limits to try and address it that way, although it had a slight effect, it did not affect the figures sufficent to notice. Unfortunately the throttle stop at max RPM is fixed so you cannot do anything with that....The manual gives several limits which range from the not more than 5 seconds examples down to the accepable..
In our case, the Engine Manufacturers continuous rated Max RPM for the Engine in question is actually is higher than the redline on the Aircraft Tacho and the Aircraft TDC RPM figures by a couple of hundred RPM, which is why I went to both Manufacturers and the CAA........ go figure.
That being the case the Engine was reving well below its Max Continuous figure but just over the Aircraft Redline by about 50 RPM in the climb, the Prop was checked and overhauled and also found to be well within limits.. That is why we could not understand how an Aircraft could possibly have a Redline lower than what the Engine was capable of producing in normal operation, naturally you would assume the prop would govern it, but that too as said was all within the manufacturers limits. There being no adjustment possible to the max RPM stop and all the fuel flows being correct, maybe we just got close to a "Blueprinted" engine.
N.B
For those in here that may not know what a "BluePrinted" engine is, It is a theoretical engine that is as close to the original manafacturers drawings as possible, hence "Blueprinted"..... a production engine will not come close to this as you will often get lips, casting marks etc such as where the induction manifold bolts onto the heads which cause poor airflows and disruptions to it and reduce performance and overall power output. That is why when you hear of a "Blueprinted" engine being fitted to a car etc it will have had all the casting marks and lips machined down to get them as smooth and close to what the manufacturer had envisioned in the design as possible, which will give you a more efficent engine that produces more power.