C201 337 approval for Franklin

flyfish1 · Post by **flyfish1** » Fri Dec 13, 2013 5:49 pm

I just received the approved 337 back from the FSDO for the McCauley c201 prop on my M4-220C. In all it was about 10 months turnaround time for the approval. Since I have the Maule extended gear we were able to get the approval without the 850 tire size limitation. They did put a limit on maximum rpm for noise abatement which is to be placarded in 1/4 inch red letters. The rpm limit is 2660 for noise while the normal redline for the Franklin 220 is 2800rpm. I am sure if as the PIC I deem it necessary to exceed this limit for safety of flight reasons it just may creep up to 2800. Anyway I do have the 337 approval and the memo from the Chicago ACO if anybody needs it for reference. I would attach it on my post if I could. Just pm me and I can email a copy.

MauleMechanic · Post by **MauleMechanic** » Fri Dec 13, 2013 5:53 pm

flyfish1 wrote:I just received the approved 337 back from the FSDO for the McCauley c201 prop on my M4-220C. In all it was about 10 months turnaround time for the approval. Since I have the Maule extended gear we were able to get the approval without the 850 tire size limitation. They did put a limit on maximum rpm for noise abatement which is to be placarded in 1/4 inch red letters. The rpm limit is 2660 for noise while the normal redline for the Franklin 220 is 2800rpm. I am sure if as the PIC I deem it necessary to exceed this limit for safety of flight reasons it just may creep up to 2800. Anyway I do have the 337 approval and the memo from the Chicago ACO if anybody needs it for reference. I would attach it on my post if I could. Just pm me and I can email a copy.

awaiting video with improved sound!!!

MauleWacko · Post by **MauleWacko** » Fri Dec 13, 2013 7:46 pm

Curtis · Post by **Curtis** » Sat Dec 14, 2013 7:08 am

MauleWacko wrote:That is great it was done. What lenght did you get for the propeller. Mine was 90-8 which made it 82 inches and 850 tires had plenty of clearnce for the 337 approval. 140 rpms is minus how many horsepower on take off? I'd tell chicago to piss up a rope there on dope. Go Northwest. Farmaule where are you??

The RIGHT to LIFE, LIBERTY and HAPPINESS. I would fly it like I had stole it!

flyfish1 · Post by **flyfish1** » Sat Dec 14, 2013 6:06 pm

I also put on an 82 inch c201 prop. Most of the 337s I have seen were limited to 850x6 tires as the smallest. My 337 approves 6.00x6 tires if I want to put them on because I have the maule extended gear. I have seen some 337s which limit the time at high rpm for noise. Unfortunately mine limits the rpm. In either case I am sure a pilot will use whatever is required for conditions. As with all other noise abatement procedures they go out the window as soon as the pilot deems its compliance causes a safety issue. I think everyone would prefer a little extra prop noise opposed to the sound of impact.

FARMAULE · Post by **FARMAULE** » Sat Dec 14, 2013 6:34 pm

Awesome news! I just returned home today from USAF officers training to a nice assortment of papers including the required 337s for my approval. Thanks to Tim's Aircraft Repair and Tim for all of his help. I plan on installing it very soon.

FARMAULE · Post by **FARMAULE** » Tue Dec 17, 2013 3:04 pm

Just curious how you guys made your RPM adjustments. Were you able to reach redline with governor or did you have to get into the prop?

MauleWacko · Post by **MauleWacko** » Tue Dec 17, 2013 3:28 pm

MauleWacko · Post by **MauleWacko** » Tue Dec 17, 2013 3:40 pm

aero101 · Post by **aero101** » Wed Dec 18, 2013 10:36 am

The redline limit for noise abatement RPM is 2660 and after 5 minutes, for normal climb out and up to 5 minutes, the RPM LIMIT IS 2800.... After 5 minutes you pull it back to 2660 is all that's about. The prop shop should be setting up for 2800 in fine pitch stops at 2800RPM... This is simply a way to getting around noise survey that satisfies the FAA in this situation.... You problem is you probably won't getting by the 2660 without reseting prop fine pitch stops which does have to be done at prop shop?? Then, if governor is set right, it will not let it exceed the 2800 under any circumstaces unless you have gov failure.l...

TomD · Post by **TomD** » Wed Dec 18, 2013 5:09 pm

I am curious on these long props w/ high RPM how much more thrust you get if the tips go supersonic and cavitate?

Seems like there should be a sweet spot just before you start cracking windows and ear drums like a C185 that you would get max thrust.

TD

JLB · Post by **JLB** » Wed Dec 18, 2013 5:29 pm

FARMAULE · Post by **FARMAULE** » Wed Dec 25, 2013 4:19 pm

Flyfish1, did you ever figure out your pitch settings. I just put my prop on today and am only making 2250 Rpm. What settings are good for a full 2800 or will this be common amongst prop shops in there tech data?

firstmaule4 · Post by **firstmaule4** » Mon Mar 24, 2014 8:54 am

Overhauling my motor and sent prop in to shop and it is out of limits can I get some help with the paper work you used to get the c201 approved currently looking for a prop now

aero101 · Post by **aero101** » Mon Mar 24, 2014 7:12 pm

I may have a McCauley 84" available soon.. I will know by end of week. Recent overhauled, probably 200 since OHC... If it becomes available will be looking for around $3500 for it.. Depends upon what happens with project acft I have and if neighbor buys engine, that will determine whether I part out or sell flying airplane.

Any good prop shop should be able to figure out fine pitch blade stop adjustment after you know what RPM you can pull with governor adjustment backed off completely... Only 2200 RPM sounds like a problem with prop or governor to me, as they're usually within 100-200RPM out from the redline of 2800 on the Franklin. Different strokes for different FSDO's on the noise abatement, RPM limits. All that I have run thru approval process allow full power / RPM for 5 min then back off to the 2600
area for noise, and we usually bring em back on RPM as soon as we clear obstacles which is neighborly thing to do anyway.

When a prop exceeds about 92% of mach at tips, blades start air cavitating and prop becomes very inefficient. At 92% it will bark quite loudly as most have heard C185 seaplane props do...

C201 337 approval for Franklin

C201 337 approval for Franklin

Re: C201 337 approval for Franklin

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