[f-AA] Engine and STC info

[Willie and Mary Jo Langholz]

All

 I had started a thread on the NAA face book page and realized that may most of you here prabably do not do facebook.

Here we go.

We now live full time in Texas on a strip at 1400 feet and I'm finding it a bit challenging with 2 people on board.....never worried at all in Minnesota with no real DA

I have a o-235 C1 on my 7Ac through the Buzz wagner stc. As I read it, that would include all variants of the o-235 through the L2C series.

My thought is to find another o-235 C1 and overhaul it while still flying the other one. The tag on my engine now states 115 horse continuous at 2600 rpm. well my plane will hit 2500 rpms level flight but thats it. Prabably becuase of my prop is a 72/44. The STC statesI could use 74/41......

Maybe my engine is not as weak as I originally thought and I should repitch my prop or fine another that would fit , pitched at 41-42 and see what difference it will make,

  I know the o-235 is a strong engine but reading back on the engine logs this is the second major OH on the current engine 

So after all my rambling the HP limit on my 7ac is in the stc not the engine so should I first find a replacement prop and see if I can hit the 2600 static?

Is my engine weak and need to go to a fresh overhaul

what about higher compression pistons ? Can one have and experimental LSA?

Thanks for your thoughts in advance.

Willie 

[Richard Holcombe]

Re-pitch

Speed is fun, but climb will save your but.

--

Not all who wander are lost.

[harveybrock]

I agree with Richard, pitch sure limits your HP output and the design of your plane isn't going to allow much speed anyway.

  I also have this issue on a different airplane. I have found a prop shop in Mt View, AR that will repitch my prop for less than $300.00. As soon as I can pull my prop, it will be be there because the density altitudes over 2500' are making the trees nervous at the end of some of the short strips.

Harvey

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[Roger Anderson]

I'm a fan of repitching when necessary.  I had the wrong prop on my last Ercoupe.  When the engine was upgraded from C75 to 85, they left the C75 prop on.  I had the prop trimmed and repicthed to correct C85 specs.  I got and extra 350 rpm and a much better climb out of it then....along with a bit of cruise speed decrease.  roger

---

From: "harveybrock" <harve...@hotmail.com>
To: aer...@westmont.edu
Sent: Monday, July 13, 2015 7:13:29 AM

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[danv...@gmail.com]

I echo Richard, Harvey, and Roger. I'm
pitched for best cruise. That is great at home in Florida where I my runway is 4000' of concrete at about 7'ASL and no serious obstacles.
I've noticed a significant difference these past several weeks flying from 3000' of grass at just 500'AGL, density altitudes of 2000' on 95 degree days, and 50+' oaks and loblolly pines at the ends. It's been a good reminder of why I had the prop pitched for climb when I live up here in Carolina.
Dan v

[John Rodkey]

Tell me about it, Dan!!!  Flying out of a 2100 foot grass runway with trees at the end and at 700 AGL and 90 degrees (3200 DA?) was a nail-biter at Sandy River, Oregon  a couple weeks ago.  My prop is medium pitch, but I would have been happy with another 20 horse power...

John

--

John (poobah) Rodkey - N9361E 11AC at Goleta

[David Polley]

What about a sparrow hawk conversion. Converts a 0235 into 125 up engine.  Might work?

David E Polley

[Jerry Eichenberger]

Sparrow Hawk STC only applies to C-152 and maybe a Tomahawk. We had a Beech Skipper years ago and tried to get it applicable but it would have taken a whole new STC. 

Sent from my iPhone

[John Rodkey]

https://www.google.com/maps/@45.4021028,-122.2287259,629m/data=!3m1!1e3

[David Polley]

Too bad. Same size engine configurations

David E Polley

[Ian Harvie]

Fit VGs I found they make a considerable difference.
Ian

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[Willie and Mary Jo Langholz]

All

Thanks for all your thoughts. I went through and did the P=V x 1056/rpm and the V= D x R/229 thing and I came to the conclusion that I still need to flatten my prop some for what I want.

Right now I have a 72" 44 pitch.... I'm thinking about 41-42.... with the o-235 it will fly about as fast as the original Champ but give me considerable more on take off and slow flight for shorter landings........ who bought a Champ to go fast anyway..... low and slow , RIGHT :)

[Aeronca Flyer]

7244 seems pretty flat, what is your static rpm?

This may be comparing apples and oranges because of different propeller profiles, but my C-90 turns a McCauley 1B90 7345 2310rpm, with a max 2360rpm allowable. I consider it to be between standard and climb.

Richard in Creswell, delving into propeller voodoo

[Richard Holcombe]

I think i heard 50 rpm per inch of pitch once.

[Willie and Mary Jo Langholz]

Aeronca Flyer, don't worry about the Voo dooo  I'm to it now that I'm not going to let a little Voo Doo chase me away. 

I haven't done a (tie the tail down and do a run up) check in some time.How ever on a straight and level flight wide open 2450-2500 max

My o-235 through the Buzz Waganor STC allows 115 hp at 2600 continuous Prop no longer than 73 or shorter than 71. So reading all the data on the original 7AC and it's variants and the o-235 and it's variants I need to match the prop to the engine to the plane for max performance.

A little pixie dust is welcome here as well.

My goal for my little Champ is to have it run at it's very best......tweak here and a tweak there and look out Chiefs here I come :) :)

It's amazing how different little things can make a big difference.

Willie

[joer...@suddenlink.net]

---- Willie and Mary Jo Langholz <wjlan...@gmail.com> wrote:
> Aeronca Flyer, don't worry about the Voo dooo I'm to it now that I'm not
> going to let a little Voo Doo chase me away.
>
> I haven't done a (tie the tail down and do a run up) check in some time.How
> ever on a straight and level flight wide open 2450-2500 max
>
> My o-235 through the Buzz Waganor STC allows 115 hp at 2600 continuous Prop
> no longer than 73 or shorter than 71. So reading all the data on the
> original 7AC and it's variants and the o-235 and it's variants I need to
> match the prop to the engine to the plane for max performance.
>
> A little pixie dust is welcome here as well.
>
> My goal for my little Champ is to have it run at it's very best......tweak
> here and a tweak there and look out Chiefs here I come :) :)
>
> It's amazing how different little things can make a big difference.
>
> Willie

I never saw where you checked the accuracy of the tach, that the throttle plate was properly adjusted for wide open, that the airbox was tight and the carb heat flap properly adjusted, that the mixture control was properly adjusted, or that the primer was not leaking fuel when locked. You could also check valve lift to be sure the cam is OK, but you would have seen some metal in the screen if the cam was going bad. These are all things that might affect power or your propeller choice and I might check them to make sure I spend money wisely on a propeller purchase. jrh

[Willie and Mary Jo Langholz]

All of the above was done in may with the exception of the valve lift ... But I always check the oil and have not seen anything.
The prop was just overhauled about 6 months ago. It was at 72/47 . I could fly faster than any Chief but took forever to get off the ground. I almost went to 42 at that time but I was in Minnesota then and chose the 44. Here in Texas I think I would benefit with a flatter pitch for take off and controlled landings. It will cost me around $500 to re pitch it or I may try to find another one that is in good shape and re pitch it to 41.