This is an Otto cycle engine, not a turbine or a diesel, and talking about limiting it to around 65% power. If the throttle is mechanically driven, WOT with fuel trim would be an AFR around 23:1 at sea level. The literature tells us Otto systems either won't run at all that lean or will run really really rough while likely having some short lived internals.You correlate the Fuel table to match the engine needs. Reduced timing results in lower map and corresponding fuel.
Trim as needed . If the ECU is tunable of course.
At WOT and a given RPM, you have X airflow which requires X fuel flow to maintain X AFR. Reduced timing has nothing to do with MAP or AFR. Timing highly affects engine efficiency, detonation margins and EGTs.You correlate the Fuel table to match the engine needs. Reduced timing results in lower map and corresponding fuel.
Trim as needed . If the ECU is tunable of course.
In post 16 the OP indicates he has done some running and reinstalled the governor.So we have a high performance airplane with (essentially) a fixed pitch prop
Extra bracing is placed in the frame and all the skins from about the cockpit forward are replaced with thicker sheet. (The skins are bonded to the frame in a T-51, so it forms a strong unit.) In none of the "incidents" with T-51s has the cockpit area deformed. And the wings were tested to 10-12gs at 1650 weight.Just looking from a distance and I'd be interested to know how much modification the original designed airframe has gone through seeing it was initially designed to fly with around 115hp?
I just wonder if you're looking to push of 450hp whether you should be looking at something like a Stewart or Thunder 51?
That said, are they still available?
Yes, this is just to make the plane flyable if your prop goes minimum pitch.In post 16 the OP indicates he has done some running and reinstalled the governor.
On top of that, I recommended fitting a partial flow filter to the system so any particles generated get a chance to leave the system before silting up places in the system or imbedding in bearings and such.
I assume the commentary on setting the low pitch stop is to leave some power available for emergency mode management, not for nominal use.
I do understand that loss of governor oil pressure in singles causes the prop to go to min pitch. It seems prudent to me to set that min pitch stop where the system can hold altitude somewhere around Vy and approach speed. Is there a reason not to do that? It might not give max rpm in the first couple seconds of takeoff, but that hardly seems needed for anyone but the STOL contest guys.
Good.Yes, this is just to make the plane flyable if your prop goes minimum pitch.
There are a lot of airplanes with constant speed props where you move the prop lever full forward and then adjust power to get the level in downwind and then descending to the runway. Sounds like you have a lot of prop for the airplane weight and approach speed. If you plan to leave the prop at cruise for the traffic pattern, you should also do tests to make sure that you have plenty of climb available by just pushing up throttle for missed approach. If climb is lethargic in the go-around with cruise prop setting, I suggest that that you figure out what prop setting gives you a good go-around response and use that from pattern entry to landing...Some info / data points / calculations:
Owners leave the prop at cruise pitch when landing. If you go to minimum pitch the plane loses speed and altitude at a "remarkable" rate. It has a very thick wing, so the airframe is very draggy. So the fear of not being able to stop the plane once down unless the prop is minimum pitch is probably not real.
It is good to know that other owners have converged on the same settings.I find it interesting that the 21" at 3000-3200 rpm is what pilots use when cruising. So just by the seat of their pants they came upon the max safe sustained power?
I fly up to 10,000 feet frequently in a Cherokee. Keep your head on a swivel and check the iPad for traffic too. You can not count on altitude to keep you clear of other traffic.I plan to fly at 7000 ft to allow for generous glide distance or plenty of bailout height. I assume this is also higher than C172s and similar GA planes fly, so less traffic. Yes? (The plane has emergency canopy releases, so getting out is easy.)
At 7000 ft, only 23” will be available anyway- but you could use it in an emergency.
Probably related to cost and reliability. Are there any other engines out there you can buy brand new for $7K and will loaf along at half redline at 160mph?Seems nonsensical to install a heavy 430-480hp engine in any airframe and then de-rate it to half HP to make the marginal PSRU live.
Standard in single engine airplanes is for hydraulic prop to go low pitch on loss of oil pressure to hub. Standard in multi-engine airplanes is to have the hydraulic prop go into feather or high pitch on loss of oil pressure to hub. In singles, the theory is a failed governor and a running engine can still be flown to an airport. In multi-engines, the theory is the good engine can still take you to an airport if the dead engine is feathered.The plan is to have Elliot Seguin fly the plane. Initially the goal will be to see if the minimum pitch setting is set for too much pitch to take off and climb well.
He has quite a bit of experience with a Stewart Mustang and a loss of prop control with it. Interestingly, that prop goes to max pitch rather than min if it fails.
The "typical" aerobatic C/S prop and governor use the counterweighted "auto feather" scheme used on multi's. This is used so that the prop does not go flat during times of transient oil pressure loss during aerobatic flight. The typical aircraft engine will handle transient oil pressure loss much better than a propeller system will handle a transient overspeed.... Some aerobatic aircraft run feathering style props for responsiveness. I do not fully understand the topic. Maybe others can help.