fixed pitch vs. constant speed

[plehrke]

Originally Posted by Dbro172

There is not much cost difference between a 320 and 360, maybe $1500. The difference from FP to CS is $5k and up.

Exactly why I went 360 with fixed pitch. (And I am not a "financial sub-standard member of the community" but may resemble one at first impression)

[PilotjohnS]

"There is not much cost difference between a 320 and 360, maybe $1500. The difference from FP to CS is $5k and up."

To paraphrase Everett Dirksen," Ya a thousand here, a thousand there, pretty soon your talking real money"

[kentlik]

Originally Posted by n5lp

Boy do I ever feel the fool. The enjoyment of the last 17 years of flying an elegantly simple and efficient design was just an illusion.

Maybe with a heavier, more expensive and more complicated propeller that wouldn't let me fly any faster but would accelerate better during the takeoff roll, I would actually be having fun.

Awesome. I hope I say the same thing...when I install my fixed pitch.

[jtppalmer050390]

I have 7A fixed pitch. Came into the pattern a few evenings ago on a 45 degree downwind at 168mph. No problem getting speed within flap range on downwind. Don't think ability to slow down should influence CS vs FP.

[KBSUP]

Go with the FP. KISS. Flown both and like simplicity.

[rightrudder]

Originally Posted by jtppalmer050390

Don't think ability to slow down should influence CS vs FP.

Not with a -7, but it would come in handy on a -9! I still like my FP on my -9A, even though it does a Schweizer sailplane impression on final. If I needed to get into shorter airstrips, I'd consider the CS.

[airguy]

Originally Posted by rightrudder

Not with a -7, but it would come in handy on a -9! I still like my FP on my -9A, even though it does a Schweizer sailplane impression on final. If I needed to get into shorter airstrips, I'd consider the CS.

I'm still in Phase I, but yes the C/S prop on my 9A definitely does give the ability to bleed energy quickly in the flare. I love it, wouldn't trade for it.

[vlittle]

Originally Posted by Dbro172

There is not much cost difference between a 320 and 360, maybe $1500. The difference from FP to CS is $5k and up.

At sea level, take off power
An IO-320B CS 2700 RPM produces 162 HP
An IO-360A FP 2250 RPM produces 163 HP

At 8000'
An IO-320B 2700 RPM produces 130 HP
An IO-360A 2700 RPM produces 163 HP

The FP is lighter, cheaper, climbs better, is faster and produces more HP.
Big problem with the IO-360 FP will be exceeding VNE, and you'll have to pull the throttle back above 8000'. The emperor has no clothes.

If you are an aircraft designer, you don't want an engine that wiil exceed the airframe Vne in normal flight. A way to get the climb performance without increasing top speed is to use a CS prop. In fact, this is the major reason why the RV-9 is limited to a 160 HP engine, but adding a lightweight CS prop is OK.

[brad walton]

The designer advised to build light and keep it simple. Doing this will maximize the wonderful handling characteristics of the design. Heavy and complex may be advantageous for those interested primarily in crosscountry.

[Saber25]

Originally Posted by brad walton

The designer advised to build light and keep it simple. Doing this will maximize the wonderful handling characteristics of the design. Heavy and complex may be advantageous for those interested primarily in crosscountry.

I agree with Brad on this and my Catto F/P on a light RV4 has absolutely no problem surmounting the 14teeners around here nor landing in short back country strips. She'll turn on a dime and bite your six. Been that way for 27 years and I'm still grinning.

Cheers, Hans