M20S horsepower increase STC

[Godfather]

6 hours ago, jclemens said:

Everyone knows physics don't apply to aircraft.....

I agree that a quantitative analysis is hard to use when making purchases for expensive hobbies/enjoyment activities.  However, for takeoff performance which is what we are talking about, I would think the aircraft lbs/hp would be a good judge. For that the 150->182r (gw) would be 16 lbs/hp -> 13.5 lbs/hp and the m20s 244->310hp (@ the same 3200lbs) would be 13.1 lbs/hp -> 10.3 lbs/hp...

[carusoam]

There has got to be a few Macs around.  If you are interested in following up in that direction.  TopProps have been replacing them one at a time.  It may take a blade from here a hub from there....

Best regards,

-a-

[Flymu2]

As far as I know only the Hartzell qualifies for 310 hp. Maybe the MT as well. I'd be happy to be disabused of that notion.

[M20F]

1 hour ago, Flymu2 said:

As far as I know only the Hartzell qualifies for 310 hp. Maybe the MT as well. I'd be happy to be disabused of that notion.

No matter how you slice it though my understanding is you need a 3 blade for the STC because a 2 blade isn't going to convert 310HP to thrust.

[Flymu2]

It's not strictly the number of blades. I flew a BE18 with 450 hp engines and 2 blade props. The diameter might be too big for ground clearance.

The 3 blade Hartzell is the only prop approved. The reason doesn't matter.

[M20F]

10 minutes ago, Flymu2 said:

It's not strictly the number of blades. I flew a BE18 with 450 hp engines and 2 blade props. The diameter might be too big for ground clearance.

Correct, you aren't going to get a big enough 2 bladed prop on a Mooney so the added blade(s) becomes needed.

[aviatoreb]

26 minutes ago, Flymu2 said:

It's not strictly the number of blades. I flew a BE18 with 450 hp engines and 2 blade props. The diameter might be too big for ground clearance.

For sure - it must be the diameter that would be needed and the low slung Mooney gear that make for 2 blades and 310hp to be incompatible.