Pa28-151 stc

[SY737]

A bit of a technical question, wanted to see the feedback.

I fly a PA28-151 Cherokee Warrior with the RAM STC that upgraded the engine from 150hp to a new 160hp engine. Would any of the V-Speeds change on it? I'm sure structural speeds such as Vne, Vno, Vfe, etc. wouldn't change, but what about speeds like Vx and Vy? These speeds relate to Power/Thrust Available/Required. Would they change at all? I'm sure it's fairly negligable, but I'm just curious. I just use the AFM numbers right now.

Any feedback is appreciated.

Tony

 

[Baronpilot244]

There should be a supplement in the aircraft detailing the changes.
We upgraded to a 160hp in our flight school 172 - gross weight changed, empty weight changed and there were a few other subtle changes.

Read through the STC paperwork (you might have to look through the aircraft maintenance logbooks) - you should find the differences as well as a superceeded weight and balance.

Bp244

 

[SY737]

All of the W&B info was in the paperwork, but saw nothing regarding airspeed changes. I'll give it another look though, it was a while ago.

 

[tgrayson]

but what about speeds like Vx and Vy? These speeds relate to Power/Thrust Available/Required. Would they change at all? I'm sure it's fairly negligible, but I'm just curious.

Vy/Vx would only change if the *shape* of the power available/thrust available curves changed. Merely raising them up or down due to power/thrust changes would not itself change the point where maximum excess power/thrust occurred. It would just change the maximum climb rate or climb angle at those speeds.

That said, whether you would see changes in these speeds with your conversion would depend on where the extra power comes from. A different engine or propeller might very well change Vy/Vx. The only 150-160 hp STC I know of for the pipers merely changes the piston shape to produce higher compression ratios.