Propeller pitch range - specific to the airplane?

[chrixxer]

Looking at the propeller log for my M20F, I see the pitch range is noted as 29.0° high, 14.8° low. Is that specific to the propeller (i.e., every HC-C2YR-1BFP/F7497 install will have the same range), to the engine/propeller combo (every HC-C2YR-1BFP/F7497 bolted to an IO-360-A1A will be the same range), or specific to the M20F (i.e., specified in A23 or ...)?

It looks like it's specified in the Mooney type certificate, so it'll be specific to the application (presumably by STC, since the Scimitar prop isn't listed on the TCDS)... Just wanted to sanity check before I start building SQL tables.

[carusoam]

Great question for Cody... @Cody Stallings

I would suspect that prop angle and blade selection is very much related to weight and speed of the plane...

All of that detail is coded into the S/Ns of the blades and hub...

So... a hub that has a set range of angles may be used on similar spec planes...

It wouldn’t take much to have something close, but not the right one...

 

When new props come out their specs are set to match the plane’s requirements... the summary report of all that tech work is essentially the STC...

No surprise... changing the blade design probably requires a different hub design....

Then Mooney owners come along... and want it lighter, stronger, and more efficient, with better ground clearance, and a KOSH discount to go with that..... 

For additional info on the TopProp and MT prop, the STCs for Mooneys are listed on their website...

See what Cody says...

Best regards,

-a-

[MikeOH]

Hmm, I'm no authority, and certainly NOT an A&P...but the 2A3 TCDS only shows he C2YR hub with 7666-2 blades for the M20F, with specs as 14 +/- 0, and 29 +/- 2 for limits.  Am I not reading it correctly?

Or, did I misread your post, and you have a non-stock, STC'd prop?

Edited May 17, 2019 by MikeOH

[carusoam]

TCDS...

a great resource for the Mooney factory data... page 23 or so for the F’s prop...

http://www.airweb.faa.gov/Regulatory_and_Guidance_library/rgMakeModel.nsf/0/60107bc8954c93a686256c24005b5075/$FILE/2A3.pdf

 

STCs for everything that came out produced by other companies.... after the fact...

typical for the 200hp engines is a range from 14° to 30° or so...

For the Turbo birds... the top end goes around 40°... bigger bite in thin air...

For multi-range birds like the O... 15 - 40° or so...

Some reason the Eagle started with a range of 20 - 40°....  the eagle also started out with a two blade prop...

the wider range probably has some additional costs...

Chrix, you brought up an interesting question! 

There are a few planes missing at the end of the list... it must not be the most updated list...

Some of the most interesting details are in the notes on the last three pages...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Bryan]

My POH specifies the pitch range, down to 10th of degrees.

[carusoam]

The tenth of a degree is important for producing the HP, to match book number performance...

Just causes difficulty when discussing all the generalities... 

Best regards,

-a-

[Cody Stallings]

1 hour ago, chrixxer said:

Looking at the propeller log for my M20F, I see the pitch range is noted as 29.0° high, 14.8° low. Is that specific to the propeller (i.e., every HC-C2YR-1BFP/F7497 install will have the same range), to the engine/propeller combo (every HC-C2YR-1BFP/F7497 bolted to an IO-360-A1A will be the same range), or specific to the M20F (i.e., specified in A23 or ...)?

It looks like it's specified in the Mooney type certificate, so it'll be specific to the application (presumably by STC, since the Scimitar prop isn't listed on the TCDS)... Just wanted to sanity check before I start building SQL tables.

It’s sensitive to the Engine an plane.

That Propeller on a J has a Different Low pitch, but the same High pitch(I have no clue why, no engineering blood in me).

What I have learned over the years with the Low pitch of a propeller, it’s a very Critical angle to setup properly. 

We will say your 200hp engine at 2700rpms +14.0 degrees is all that engine will twist. Meaning it slowly gains RPM above 2700rpm on the roll. That’s what you want, cause it’s basically a seamless transition to the Governor taking full control of the Propeller. No surging as the Gov senses the upcoming Overspeed an smoothly adjusts blade angle to hold RPM.

 

NOW!!!

Same Prop/Blade, Same 200HP But with +13.0 of Low pitch, or even +13.5 of Low pitch, when the power is advanced the propeller will meet an exceed the 2700rpm causing the Governor to get “surprised” with rapidly building RPM, so it sends a large amount of oil to the prop cylinder which it most cases pulls the propeller down 50 or so RPMs, then the Governor will release causing the surging you hear on takeoff of sometimes.

On to the High Pitch.

Anthony is sorta on the right track(till he derails..lol). The High is configured around where the plane is going to Operate Altitude wise, an the Vne of the aircraft in a power on decent. In Most cases in optimal conditions most CS piston Propellers will hit the high pitch stop in a nose down attitude power on 10-15knts from the Vne, at that point the propeller will “ go fixed pitch” an the Governor is no longer capable of controlling RPM, an you will see a rise that is only controllable with aircraft pitch.

Take Bryan’s build sheet for his C221 McCauley, it’s shows +38.0 of High Pitch so At 15k Ft he’s cruising somewhere in the area of +25 to +30 degrees @ 65% 70% power. The other 8 degrees is for when the nose gets pushed over with that power setting an ATC asks for “No-delay thru 10K” an you dial in 1000--1200fpm so you have a buffer of blade angle to utilize to keep off the high stop.

Now to the M20S an it’s Original Prop an Blade angle. The McCauley “toothpick” 2 blade that graced the nose of the S an some of the R’s was an engineering disaster. 

Trying to Derate the engine via RPM an hooking a small Propeller to it , you have to turn up the Low Pitch in order to even get it to move.

Once it got off the grd an in cruise on step it was fast as hell. It could pull a more aggressive blade angle while corkscrewing  through the air. But the HP increase an 3 blade turned them into a well rounded machine.

 

 

 

[carusoam]

Some people say I don’t know what I don’t know...

I’m all smiles while I am reading about Mooney props...   

There is a lot I didn’t know!

Fortunately, when I don’t know....  I do know a good prop guy to go to... 

Thanks for filling in so many details, Cody!

Best regards,

-a-

[skydvrboy]

8 hours ago, Cody Stallings said:

Anthony is sorta on the right track(till he derails..lol).

Aren't we all! 

[Cody Stallings]

1 hour ago, skydvrboy said:

Aren't we all! 

Yes Sir!!

[chrixxer]

I should have expected all the digression ... My question was pretty simple, and I think I've got it figured out: Specific to the airframe. More or less. So it's data that should "live" in a separate table, not tired directly to a particular prop or aircraft (e.g., an M20J with a McCauley B2D34C212/78CDA-4 is Low 14° ± 0. 2°, High 27.5° ± 0.2°, while the same plane with a McCauley B2D34C214/90DHB-16E or -16EP package is Low 13.9° ± 0. 2° High 33.0° ± 0.5°, etc). So I broke it out into what would otherwise be a straightforward many:many link table:

+--------------------------+------------------+------+-----+---------+-------+
| Field                    | Type             | Null | Key | Default | Extra |
+--------------------------+------------------+------+-----+---------+-------+
| aircraft_id              | int(10) unsigned | YES  | MUL | NULL    |       |
| engine_id                | int(10) unsigned | YES  | MUL | NULL    |       |
| propeller_id             | int(10) unsigned | YES  | MUL | NULL    |       |
| pitch_range_high_feather | varchar(255)     | YES  |     | NULL    |       |
| pitch_range_start_lock   | varchar(255)     | YES  |     | NULL    |       |
| pitch_range_low          | varchar(255)     | YES  |     | NULL    |       |
| pitch_range_reverse      | varchar(255)     | YES  |     | NULL    |       |
+--------------------------+------------------+------+-----+---------+-------+

[chrixxer]

SELECT
    aircraft.id AS id
,   aircraft.serialno AS sn
,   aircraft.tailno AS registration
,   aircraft_make.make AS manufacturer
,   aircraft_model.model_number AS model
,   aircraft_engine_propeller_link.pitch_range_high_feather as pitch_range_high_feather
,   aircraft_engine_propeller_link.pitch_range_start_lock AS pitch_range_start_lock
,   aircraft_engine_propeller_link.pitch_range_low AS pitch_range_low
,   aircraft_engine_propeller_link.pitch_range_reverse AS pitch_range_reverse
FROM
    aircraft_engine_propeller_link
INNER JOIN aircraft ON
    aircraft_engine_propeller_link.aircraft_id = aircraft.id
INNER JOIN aircraft_model ON
    aircraft.aircraft_model_id = aircraft_model.id
INNER JOIN aircraft_make ON
    aircraft_model.aircraft_make_id = aircraft_make.id
WHERE
    aircraft_engine_propeller_link.propeller_id = 1;

+----+--------+--------------+--------------+-------+--------------------------+------------------------+-----------------+---------------------+
| id | sn     | registration | manufacturer | model | pitch_range_high_feather | pitch_range_start_lock | pitch_range_low | pitch_range_reverse |
+----+--------+--------------+--------------+-------+--------------------------+------------------------+-----------------+---------------------+
|  1 | 690039 | N803RM       | Mooney       | M20F  | 29.0°                    | n/a                    | 14.8°           | n/a                 |
+----+--------+--------------+--------------+-------+--------------------------+------------------------+-----------------+---------------------+

Edited May 17, 2019 by chrixxer

[MikeOH]

UGH!

I should NEVER have read this thread....now, I'm concerned if my prop is correct on my M20F!

I have the original build sheet for the prop which was NOT the original prop on the plane.  It shows as a HC-C2YR-1BF with F7666A blades.

The 2A3 TCDS for the M20F shows both 2CYR and 2CYK versions of the NON B hub as acceptable, but only lists the 2CYK version of the B hub!

YIKES!

 Further, there is no mention on the TCDS of the 'F' on either the hub, or blade, part numbers???  Are those revision letters that are ok? Or??

Last, the TCDS ends with a -2 after the blade number.  That's not on the prop build sheet.  Or, is that just the number of blades being referred to on the TCDS?

I'd sure appreciate it if @Cody Stallings would respond, please.

 

Thanks!

[PT20J]

Prop data should be per TCDS if Mooney certified it, or by STC if someone else certified it. Often Mooney applies STC'd mods at the factory on new aircraft (speedbrakes for instance). The logbook should show this and the STC paperwork would have been supplied. If something is added by STC later, it should be logged and the paperwork should be in the airplane file.

Skip

[Cody Stallings]

4 hours ago, MikeOH said:

UGH!

I should NEVER have read this thread....now, I'm concerned if my prop is correct on my M20F!

I have the original build sheet for the prop which was NOT the original prop on the plane.  It shows as a HC-C2YR-1BF with F7666A blades.

The 2A3 TCDS for the M20F shows both 2CYR and 2CYK versions of the NON B hub as acceptable, but only lists the 2CYK version of the B hub!

YIKES!

 Further, there is no mention on the TCDS of the 'F' on either the hub, or blade, part numbers???  Are those revision letters that are ok? Or??

Last, the TCDS ends with a -2 after the blade number.  That's not on the prop build sheet.  Or, is that just the number of blades being referred to on the TCDS?

I'd sure appreciate it if @Cody Stallings would respond, please.

 

Thanks!

Your Fine.

The K Flange is what the plane was approved with years ago. The R flange(C2YR) is just the newer version.

 

The -1B(F) an (F)7666A-2 just means the propeller has large knob blades. Strengthen pitch change Mechanism. Yet another very desirable update.

The -2 means two inch diameter reduction from the Blade Design of 76 inches. That -2 puts you at 74 inches to comply with the TCDS.

Also, the B in the hub design dose not mean it’s a B hub. The B has to be in the Serial Number(CH1234B)

[MikeOH]

23 minutes ago, Cody Stallings said:

Your Fine.

The K Flange is what the plane was approved with years ago. The R flange(C2YR) is just the newer version.

 

The -1B(F) an (F)7666A-2 just means the propeller has large knob blades. Strengthen pitch change Mechanism. Yet another very desirable update.

The -2 means two inch diameter reduction from the Blade Design of 76 inches. That -2 puts you at 74 inches to comply with the TCDS.

Also, the B in the hub design dose not mean it’s a B hub. The B has to be in the Serial Number(CH1234B)

WHEW!  I can sleep again.

Thanks for the thorough answer, and clarification that the "B" hub indication is in the S/N.