Climb prop questions

Huckster79

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Huckster79
so I understand every airframe is different, but is their any rule of thumb of what a climb prop would gain you over a standard?

I have a Cessna 140, as it’s getting warmer even around just 70 it’s obvious one will have to be very cautious as weather heats up- noting the difference I’ve seen between 30 and 65...

She’s got a c85 stroker with 7148 (standard) prop. If I am getting 500fpm in a certain scenario of weight and DA - what might I expect with a 7146 or 7145???

Anyway to calculate approximately what the gain might be?
 
so I understand every airframe is different, but is their any rule of thumb of what a climb prop would gain you over a standard?

I have a Cessna 140, as it’s getting warmer even around just 70 it’s obvious one will have to be very cautious as weather heats up- noting the difference I’ve seen between 30 and 65...

She’s got a c85 stroker with 7148 (standard) prop. If I am getting 500fpm in a certain scenario of weight and DA - what might I expect with a 7146 or 7145???

Anyway to calculate approximately what the gain might be?
Not really,, but don't do it, you already have the premium prop.

a 45 will allow you to over speed.
 
Not really,, but don't do it, you already have the premium prop.

a 45 will allow you to over speed.

Would a 46 allow me to overspeed? Just curious...
 
Would a 46 allow me to overspeed? Just curious...


What is your static RPM?

What rpm are you typically climbing at?

At what altitude do you not overspeed at full throttle cruise?

What is your normal cruise altitude?

What’s your redline?
 
You need more horse power not less prop pitch.
 
You need more horse power not less prop pitch.

Different engine not an option, different prop is, budgetwise...

I know she’ll never be a homesick angel besides solo when it’s 15 degrees out, am just kicking around the idea of some more fpm by trading in some mph with what ponies are available...
 
What is your static RPM?

What rpm are you typically climbing at?

At what altitude do you not overspeed at full throttle cruise?

What is your normal cruise altitude?

What’s your redline?

I don’t recall off top of my head some of those - I will get em and reply once I got em...

Normal cruise I can tell ya is 2500...
 
My 140 has a tired O200A with a 6946. Static has been okay with the tired engine but she is getting a fresh O200A within the next couple of weeks. Randy Thompson says the static will be too high so I may be prop shopping before I’m done.

Maybe the stroker will be okay with a 46. If so,I don’t expect it to give you any drastic climb rate increase.
 
Not really,, but don't do it, you already have the premium prop.

a 45 will allow you to over speed.

You are correct sir! An inch of twist would over speed me! My mechanic lent me his prop rpm reader tool tonight. I’m 20rpm short of max static now... that 72 year old automobile tach is pretty dead nuts on too!

Also figured out tonight that letting her get up to static and then release brakes made a tremendous difference! I’m not a “jammer” I like to smoothly ease any knob, lever, etc... Well coming out of a 180hp 172 that I was always light, me and a couple kids... pulling onto runway and easing it in over a few seconds was fine...no where close to gross, the 140 is close to gross before I jump in, lol. An easy rolling power add in the 140 just meant a lot of burned runway easing in that throttle...

So I kicked that bad habit tonight.. still not jamming her but I’ll stand on the brakes while I ease her in then I’ll let all 85 or so of those continental ponies Loose!
 
What is your static RPM?

What rpm are you typically climbing at?

At what altitude do you not overspeed at full throttle cruise?

What is your normal cruise altitude?

What’s your redline?

Prop shopping is done! No need to. An inch of twist, if it gained me 50rpm would put me over. 2300 is max, she was at 2280...

Climb out was at about 2400 rpm

She gets to edge of kissing red line full throttle at 2000 ft in cruise.

Well now that no new prop is needed, guess I can get those VGs!
 
Prop shopping is done! No need to. An inch of twist, if it gained me 50rpm would put me over. 2300 is max, she was at 2280...

Climb out was at about 2400 rpm

She gets to edge of kissing red line full throttle at 2000 ft in cruise.

Well now that no new prop is needed, guess I can get those VGs!

That was the cheapest airplane project I’ve seen in a long while!
 
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