Prince P-Tip Prop Failure

[3ddd]

your sure right about not worth it

[KTS]

The sticker on the prop said it was rated at 6250 RPM.

Never acutally tached it on the ground but the prop would only go supersonic in the air so I felt comfortable that I wasn't over reving it.

The airplane Steve is referring to is the Cessna Skymaster. The rear engine in the pushing configuration was having problems due to the exhaust.

I have the muffler cut at a forward angle on my DA 150 powered H9 Ultimate. I am running a Mejlik 32 X 10 carbon fibre prop and have had no issue.

In light of the damage to the airframe, it would have been nice to have the propeller replaced.

Comments from the peanut gallery at the fly in are that Prince has never been known for their customer service. This was my first (bad) experience. I did run the same prop on my Comp ARF 3.3 Yak w/ 3W 200TS. It truly made that engine come alive.

Obviously they do not value the modeling segment of their business. Needless to say the $ 271 quote, less the 10% of course, would be better spent at another prop vendor.

[3ddd]

for that price buy you three bolly's

[hpapilot]

A 34" Diameter prop going 6250 rpm has a tip-speed of about 632 mph. What speed are you figuring "supersonic" to be? If you estimate 700 mph (I dont know what altitude and temperature you're flying at) you must have been well over the RPM limit to hear the tips go supersonic.

Just food for thought.

RJ

[KTS]

85 Degrees F. Not too sure of the elevation of Rockford Ill.

[hpapilot]

At that temp, the chart I have says Mach 1 is actually 780 mph. Sooo....

[Flyinrazrback]

The P-tips unload in the air like no other prop, it would not surprise me if you exceeded the max rpms on the prop. Prince doesn't need the $$ from the model props, he makes all his dough on the full scale stuff. Understandably there is not very many options available out there for the 200cc+ engines. Maybe check out the ZM props that RCS carries for the 210.

[KTS]

Elevation: 730 ft / 222 m. 84.3 °F / 29.1 °C ... Rockford, IL.

[SleepyC]

I really wonder if you didn't pop the max RPM unloading in the sky.

I mean there HAS to be a reason all P-tips have a Big WHITE sticker stating the MAX RPM the prop can take Gel coated into the prop.

Well if I learned anything here , its that I for one will TACH my P-tips a few RPMS below the limit on the ground!

[KTS]

It is what it is!

http://www.aerographix.biz/p-tip_props.htm

My post was sent as an FYI to anyone who might be running this prop and engine combination. You can infer what you want from the MFG's response.

[SleepyC]

I'm sorry to hear this happend to you.
I wanted to make sure I made that clear, and again, I'm not trying to be a stick in the mud, I'm just trying to figure out if it was the RPM's. Because I just bought 3 of these props, and will be flying a nice new 40% with them, and I want to take every precaution!!

[Flyinrazrback]

Sleepy, the P-tips unload like heck, so do not let them run WOT for extended periods of time. These are a 3D prop for low speed flying, not the big over the top maneuvers. If you let them unwind too much, you are cruising for trouble.