HORSEPOWER UPGRADE

[minton]

Sure would be nice to get a smooth running six cyl. engine under the hood.

[ak2711c]

Rumor has it that Tom at XP mods retained all his STC's at the auction and is now operating under TD Aerospace. He is in the process of getting FAA approval to start producing his products and conversions again. I heard this second hand so take it for what it is. The guy I talked to had talked to Tom yesterday.

[falco]

Looks like an alternative, eventually, might be the Lycoming IO-390 engine at 210 hp. Data on one installed on a C-175 reportedly gained about 5 mph vs the IO-360 (Lyc), 180 hp engine, but quite a bit smoother. Doubt it would be as smooth as the Continental IO-360, but maybe a longer life engine? Maybe someone will get an STC for the Continental IO-360 again. Hopefully if they do and the engine happens to have come from a Cessna 172 Hawk XP it will permit the 210 hp vs the Hawk's 195 hp. I think its only an rpm difference. It only comes down to $$$$$$$$$$$

Hawk XPs are normally 195 hp, there is an STC by a guy named Isham to set the governor faster and IIRC move the low pitch stop in the propeller.

[blueldr]

It is my understanding that Cessna derated the IO-360 engine by reducing the RPM in the Hawk XP to to quiet it down . This was also done on the C-182 for the same reason except they reduced the RPM and raised the BMEP to maintain the same HP so they would not have to recertify the airplane.

[170C]

I heard years ago that the reason the Continental IO-360K (?) was derated to 195 hp on the Hawk XP had to do with certification. Something about keeping the hp under 200 hp. Don't know if that is true or not and if so I don't have any info regarding what the engine producing 200 or 200+ hp does to an aircraft's certification. Maybe some of you do and will enlighten us.

[minton]

TD aerospace has a web site w/ contact phone numbers and Email address.

[GAHorn]

I heard years ago that the reason the Continental IO-360K (?) was derated to 195 hp on the Hawk XP had to do with certification. Something about keeping the hp under 200 hp. Don't know if that is true or not and if so I don't have any info regarding what the engine producing 200 or 200+ hp does to an aircraft's certification. Maybe some of you do and will enlighten us.

Certification rules have fuel/oil endurance/capacity rules. If you raise the horsepower....you must raise the fuel/oil endurance (capacity) .. Unfortunately, larger fuel tanks mean more fuel as WEIGHT...which affects gross weight and performances.... and affects necessary structural-strength rules. (Remember when Cessna reduced 40-degree full-flap settings on current production airplanes to 30-degrees? That was due to balked landing-climb requirements and the fact that the rear doorposts were not strong enough for the higher weights if using 40-degree flaps. They'd already penalized themselves structurally by adding "omni-view" rear windows.)
So it becomes a sliding-scale/moving target for any changes made. For that reason (and others) engines are sometimes de-rated when installed into existing designs.