need a prop :(

[N74DV]

well, 43122 is in for annual right now. My IA called to tell me that there is no record of the metal prop that is on it now ever being installed. He also stated that the metal prop on it now appears to not be a prop that is allowed. He cannot find it on an approved list anywhere.

So what it comes down to is I will probably be needing a new prop.

I know metal ones are pricey so maybe I should go with a wood prop? I dunno. I'm clueless here and need some help and feedback.

what to do??

[barnstmr]

Re: need a prop

DJ
Send me an email direct. I may be able to help with a DER approval.

[email protected]

Regards,

[N74DV]

Re: need a prop

my prop is a McCauley 1B90 74-45. It is called a Klip Tip prop.

Is this prop the same as a McCauley 1A90 but with angle cut clipped tips? Anyone know? My IA seems to think it is. If it is, seems like an approval for it would be not too bad... what do ya think Terry?

[barnstmr]

Re: need a prop

DJ - Check your email. I have good news.

[Guest]

Re: need a prop

my prop is a McCauley 1B90 74-45. It is called a Klip Tip prop.

Is this prop the same as a McCauley 1A90 but with angle cut clipped tips? Anyone know? My IA seems to think it is. If it is, seems like an approval for it would be not too bad... what do ya think Terry?

look up the prop type certificate, look for note #9 (or #6) it says that 1B90 and 1A90 are the same

[Vasey fan]

Re: need a prop

Is it really a 74" diameter? If so, it's a little too long (per the TC), but that's a whole lot easier to fix than too short.

[barnstmr]

Re: need a prop

Vasey Fan - Look at note 3 on the TCDS. 74 inches is OK.

3. McCauley 1A90 with the following limits: Static r.p.m. at maximum permissible throttle setting: Landplane: not over 2210, not under 1960 Seaplane: not over 2210, not under 2070 No additional tolerance permitted. Diameter: not over 74 in., not under 72.5 inc BC-65, BCS-65, BC12-D, BCS12-D, BC12-D1, BCS12-D1 +21 lb. (-46)

[Vasey fan]

Re: need a prop

Leave it to the Feds - all the BC-12 variants on pages 3-6 have 72" listed for max under "prop limits". Which one do you go with?

[N74DV]

Re: need a prop

thanks for the email and details Terry! Looks like my 1B90-CM7445 may substitute. BUT the TCDS for the McCauley props says that the "CM" designation means SAE 1 hub and STRAIGHT TIP blades. Mine are the Klip Tip variant. It even has stamped into the hub "Klip Tip" so it came that way from McCauley but I didn't see anywhere on the TCDS where Klip Tip props are referenced.

[Robert Lees]

Re: need a prop

If I remember correctly, the 1A90 blades are rounded, and the 1B90 are squared off (hence "klip-tip")


If you contact Mark Julicher, he has a copy of the MacCauley letter that should help you demonstrate that the 1A90 and 1B90 props are equivalent. (from this thread).

Perhaps Mark can send me a copy too, and I can post it on the Foundation website for all.