[STEVE]

STEVE on June 1, 2024 at 10:06 am #22549

Hi Ken;
I’m grateful that you updated me on the solution your AME discovered.
Glad your airplane is now flying well again.

Best,
Steve

[Ken]

Ken on May 31, 2024 at 9:56 am #22548

Hi Steve,
Thanks for your response, I went on a flight and verified that only 2200 rpm climb and cruise. After discussing with AME further, I had another AME look at it and he discovered timing set to 20 degrees instead of 25 degrees. Now 2400 static and 2600 in flight. The airplane is new to me and turns out timing off since before I owned the airplane and the first AME missed timing being off.
Thanks again for your response.

[STEVE]

STEVE on May 23, 2024 at 4:13 pm #22542

Hi Ken;
I’ve expanded my reply:
I need a little more information; is this 2200 rpm number a change from a previous static rpm reading?? If so, I’ll need to ask more technical questions about the engine condition, such as has there been changes in compression ratios, a change in the propeller, or recent maintenance on your engine.
What is the altitude of the airport where you are experiencing this on-ground static rpm? As I’m sure you know, there’s less atmospheric pressure at higher altitude airports, hence less pressure to push the oxygen into the cylinders at higher altitudes. 

What does your propeller look like? It should look like it’s new (ish) and not have any visible defects. The longer aluminum fixed pitch propellers are in service the less effective they become simply because part of the normal servicing is reshaping the leading edges with files to restore the leading edge shape and remove any divots or dings. This does remove blade material. 
Sensenich (www.sensenich.com), the prop manufacturer, or a competent prop shop can send you the minimum widths at a couple of stations (distances) from the hub to see if you prop is worn below limits. 

The Type Certificate Data Sheet (TCDS) for your PA 22 with a Lycoming O-290 engine lists three propellers. The first is a wood Sensenich 74FM59. The static rpm limits for that prop are not over 2400 nor under 2200 rpm.

The metal props include the Sensenich M76AM-2 and the M74DM. According to the tech support folks at Sensenich, the 76AM-2 is no longer in production; the 74DM is the current offering.  The static limits for both of these propellers are not more than 2450, nor less than 2150 rpm. 

The part number for the wooden prop includes the diameter (74) and the pitch (59). 

The part numbers for the metal props do not include a pitch number, only a diameter number. 
Your 2200 rpm static reading is within the static rpm limits for both of the metal propellers, so legally you’re OK. But if the static rpm has decreased, I suggest you check the following items to determine why your engine is not producing as much power as it was.
• Compression tests; Lycoming suggests that all pressures be within 5 psi of each of the others; and that if any pressure drops below 65 psi/80 to retest after 10 hours of flight. 
• A partially blocked muffler outlet—it’s not uncommon for the internal baffles in a light plane “muffler” to partially fail resulting in chunks of baffle falling to the downpipe entrance.
• Induction leaks
• The Lycoming O-290-D engine has solid lifters so the valve lash (clearance) must be checked at regular intervals. The proper clearance is 0.007 to 0.009 inches.
According to the Operators Manual of the O-290D, at 2200 rpm the engine is producing approximately 77 brake horsepower at the prop. At 2450 rpm—the maximum static rpm permitted—the engine would be producing 105 brake horsepower at the prop. The only down side of upping the static rpm is the increased fuel consumption (8.75 gph vs. 6.2 gph) But the performance increase would be noticeable. 
If your static rpm has always been 2200, and you want the engine to produce more power at a higher rpm, your metal propeller can be re-pitched. Re-pitching to a higher static rpm will reduce takeoff roll and increase climb rate, but will reduce cruise speeds and increase fuel consumption numbers.
A propeller repair station will be able to re-pitch your prop. 

It’s a little unusual to have the static rpm (on the ground, brakes locked, on a calm day) be the same as the full throttle cruising flight rpm. Has there been any change recently in your full throttle flight rpm?

Let me know the answers to these questions so I can better answer your question.

Thanks,
Steve
 
Please let me know if there’s anything else I can do for you.

S

[STEVE]

STEVE on May 22, 2024 at 10:20 am #22538

Hi Ken;
I need a little more information; is this 2200 rpm number a change from a previous static rpm reading?? If so, I’ll need to ask more technical questions about the engine condition, such as has there been changes in compression ratios, a change in the propeller, or recent maintenance on your engine.

What does your propeller look like? It should look like it’s new (ish) and not have any visible defects. The longer aluminum fixed pitch propellers are in service the less effective they become simply because part of the normal servicing is reshaping the leading edges with files to restore the leading edge shape and remove any divots or dings. This does remove blade material. 

If the static rpm has not changed then the following applies: 
The Type Certificate Data Sheet (TCDS) for your PA 22 with a Lycoming O-290 engine lists three propellers. The first is a wood Sensenich 74FM59. The static rpm limits for that prop are: not over 2400 nor under 2200 rpm.

The metal props include the Sensenich M76AM-2 and the N74DM. The static limits for these are not more than 2450, nor less than 2150 rpm. 
The part number for the wooden prop includes the diameter (74) and the pitch (59). 
The part numbers for the metal props do not include a pitch number, only a diameter number. 
Your 2200 rpm static reading is within the static rpm limits for that propeller.
However your metal propeller can be re-pitched. Re-pitching to a higher static rpm will reduce takeoff roll and increase climb rate, but will reduce cruise speeds.
A propeller repair station will be able to re-pitch your prop. 

It’s a little unusual to have the static rpm (on the ground, brakes locked, in a calm day) be the same as the full throttle cruising flight rpm. Has that changed?

Let me know the answers to these questions so I can better answer your question.

Thanks,
Steve
 

[Ken]

Ken on May 14, 2024 at 4:50 pm #22530

Does anyone have a suggestion of why my lycoming 0-290D in my Pa-22 will only run at maximum of 2200 RPM. 2200 is the max I can get either static or while flying, We have checked tach with a Trutach, We have also checked fuel screens etc and have good fuel preassure. Also have checked to make sure carb heat isn’t partially on. Checked timing on mags everything good there too.