Prop advice to Lyc O-235 L2C

[LesBoatright]

Thanks Sean & Dan!
Very Helpful Information. And thanks for the quick reply.
I posted a much more detailed response, but apparently the forum times out, and I lost it all. I'll type faster and not so much this time.

At Wide Open Throttle, during a 1 minute run, we saw a high of about 2140 RPM, and a low of about 2080 RPM on the GRT Sport EX display. Our RPM input comes from the P-lead of each Mag, and we have a LH/RH selector switch so we can switch the input when one Mag is OFF during a Mag check.

Great suggestion about using an optical Tach. A Hangar neighbor suggested same, and loaned me his pocket TruTach RPM checker. We took the day off from the project today, so I have not had chance to re-do the run-up and independently verify our RPM readings, but I feel they are accurate since they are based on the impulses coming from the mags. We will check with the optical checker next time we run engine.

Per the book numbers, our O-235-C2C has slightly less HP than the -L2C series that Sean has, which may account for some of the RPM difference.

I think we may also need to read up on idle and mixture adjustments for the Carb. We have not changed that since we got engine. The engine idles at about 750 RPM, and feels a little rough to me. It doesn't shut off, but not as smooth as it is at say 1000-1200 RPM. We may be running a little lean at idle?

I'll look to see if I can find an EAA Hints for Homebuilders on Carb adjustments. I have the O-235 operator's manual and it has some guidance, but more detail would be nice.

Also, we did mag checks and Carb Heat check at 1700 RPM, and saw no discernible change in RPM regardless of 1 Mag or 2, and with Carb Heat ON or OFF. So there's some more investigation for us to do there. Maybe a Mag check at Wide Open to see if there's an RPM response.

Last, I did a brief taxi of maybe 300 yards total, out and back to the T-hangar. I liked the responsive ground steering as compared to the Citabria I've been flying recently. The brakes were good and firm, and seemed plenty adequate, but they were noisy and squeaked a good bit. I suspect that has more to do with them being brand new than anything else.
It was exciting to have our project move under it's own power for the first time!!

At the 6 month mark into our build, we're calling our build done less the testing, tweaking, calibrating, and paperwork.
Thanks again. Bob, Ed, & I appreciate any more insights you might have.
Les Boatright
Panther Co-Builder
SN 083

[Seansull]

Hi Les,

I am seeing about 2370-2400 rpm static with my 0-235 L2C (118 hp at 2800 rpm) and my WC68PM-65 prop that Dan set me up with.

I am seeing the following speeds straight and level. All of these numbers were preformed at 3500 msl at around 90 F.

RPM IAS
2800 159 mph
2700 150 mph
2600 145 mph
2550 142 mph

Full throttle climb 115 mph @ 2500 rpm climbing 1240 fpm
135 mph @ 2650 rpm climbing 900 fpm

Hope these numbers help you out!

Sean

[danweseman]

Les
You should be seeing "around" 2300 rpm static with the WC68PM-65. In your post you didn't say what you are getting?
Also the first question when dealing with props "Is your tach accurate" . WIth EIS sysetems its very common to have to play with the settings etc to get accurate RPM readings. We always use a hand held external optical "prop tach" verify the Tach readings early in the testing. I can bring one down with me If we get down to look over your plane.
Let us know the rpm you are seeing

[LesBoatright]

Just a follow-up question related to the subject of this thread . . .

WHAT would be the expected Static RPM for an O-235-C2C (108 HP) at Wide Open Throttle (W.O.T.) using the Sensenich Prop you mentioned below (model: WC68PM-65)??

We got our baffles done, got all cowled up, and did a full-power run-up today. Good Oil pressure & temps on a hot day.
Ran smooth & strong, but we have some questions about what we saw for Static RPM, and about our mag checks.

Thanks!
Les Boatright
Panther Co-Builder
SN 083

[danweseman]

Sean
Just wanted to give you a heads up on another Prop option for the smaller "traditional" aircraft engines IE TCM 0-200/0-240,lycoming 0-235, and Franklin 4b-235(sport 4),all inn the 100-130 hp class. Sensenich has a deigned a new prop series for the Panther with these engines. The are of the newer swept tip design , which are efficent ,quiet,and have a attractive appearance. These are Wood core composite props with urathene Leading edges,of a similar design as the props we recommend on the Corvair/Panther.
We have a OEM with Senesenich and Whirlwind propellers. We have flown props from Tennessee,Prince,Sterba,Catto,Culver ,Warp, Whirlwind,And Sensenich.
For Wood Or wood composite props we have had the best overall experience with Sensenich. Frankly all the modern wood /wood composite props work well and when PROPERLY matched will yield similar performance. Stories of one "magic" prop that works so well is usually due to the prop it replaced not being optimal for the combination.
We like Sensenich because they typically get very close to optimal performance on the first try, meet the delivery schedule ,and they have been virtually perfect quality!
Another thing to consider about buying a Sensenich through SPA, If you get the prop and decide you want a little more or less RPM etc, we can likely send this prop to a another builder and get you one that is exactly what you wanted !
The new prop for the the 0-235 cost 1455.00 ,comes in white, black or grey with red or black tips and has urathene Leading edges.
Hope this helps Some

[Seansull]

.....quick add to the above post. Any expericence with Prince P-tip prop?

Thanks!

[Seansull]

Hey All,

I am ready to order my prop, and would love some input. Here are the facts...

Lycoming O-235 L2C (118hp)
Panther LS wing
Home airport altitude 800'
Texas.....hot

Primary mission will be aerobatics with about 40% XC flying.

I am considering a 3 bladed Catto fixed pitch, Sense 2 blade ground adjustable, or anything else that makes sense.

Thanks in advance!