The following is in response to a question asked by a user which is no longer in the database:
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We learned to respect our 170 with the beloved old O-300. Then we learned to really love it with the 220 Franklin. We enjoy flying around ID, UT, CO and AZ... There's a reason we did that engine conversion!

We did a fair amount of flying into those areas in the summer prior to the conversion. It was a lethargic 2-person airplane with minimal camping gear. We stressed out out quite a bit over fuel (weight) management and made all our departures before or very shortly after sunrise. I remember that the oil temperature ran a little hot, and especially so when climbing out, of course.

I can't quote performance numbers (I am not at home with access to a POH) but the Cessna 170 association website (www.cessna170.org) has the owners/ops manual online. I think you have to be a member to access that section though ($35/year).

The 170 is a really fun, honest airplane to fly. If you can find a bird with a healthy but nearly timed out engine (with price to reflect it), You'll learn how to handle it and respect it. Then do one of numerous engine conversions that are available and you will have a really great 4-person travelling machine with really classic lines to boot!

M

The 170 is a good 2 people plus camping gear airplane-- at sea level &/or in cool weather. It's an early morning mountain plane, at least in the summertime. A lot of guys up north put on an 80" prop, usually pitched about 43 --as opposed to my 76-51-- you see a big gain in TO & climb but of course a drop in cruise speed at the same rpm. Some of them guys just turn it up higher, so they don't lose too much compared to a "standard" prop at "standard" rpm (2400-ish). Due to the flat prop, the manifold pressure is low so you don't really work the engine very hard that way. Of course, they are slower than a 76-51 propped 170 turned up the same. I used to cruise at 2400-ish for 112-115 mph, nowadays I usually turn 25-2600 & see 120 to 125- this time of year anyway.
I think if you're gonna go in the mountains you'll want one with more umph. IMHO it's cheaper & easier to buy one all ready to go than to convert it yourself. A friend of mine is in the process of converting his Swift to an IO-360 Lyc & he sez he'd never do it again.
If you're interested in a Franklin-powered 170, a fella named Paul Rostykus in southern Oregon has a 52 170B for sale that he converted about 5 years ago. It's on Trade a Plane online for $48K, seems like a pretty good deal if it's in good shape.

Eric

Hi John,

We've had the Franklin for over 3 years and almost 200 hours. We haven't had to test parts availability yet. ECI has some available on their website. I was reassured by Franklin Engines (Ft. Collins) right after P&W bought PZL that they had a comprehensive inventory. However, I would be hesitant to buy this STC again unless ECI (or somebody else who's reputable) buys Franklin from P&W and resumes production. As for our conversion, I am still very very happy with it. The performance and smoothness for the $ is unbeatable. Our PZL Franklin runs very cool (verging on too cool - we bolt on a winterization kit for the oil cooler in the fall) and doesn't leak oil at all. It consumes about a quart every 5 tach hours.

If I were looking to do an engine conversion tomorrow, I'd probably opt for XP mods Continental IO-360 STC. But it's expensive and lotsa extra work (fuel injection return lines). The only 2 things I have against the Lycoming O-360/CS prop mod are the changes in the cowling/nose bowl and the vibration factor. My Dad has the Lyc in his 172 and it has been a great engine.

A stab at our performance numbers:

Ce170b-220 Observed Climb Performance numbers:
Conditions: Gross Weight, Standard Atmosphere & 100 MPH IAS (Vy would yield a higher climb rate):
5K MSL, 25" MP, 2600 RPM: 1000 FPM sustained
10K MSL, 20" MP, 2600 RPM: 500 FPM sustained

Ce170b-220 Observed Cruise Performance numbers:
Conditions: ISA, leaned 50 degrees COP @ 5K MSL; leaned to peak @ 10K MSL
5K MSL, 25" MP, 2500 RPM, 133 KTAS, 11.0 GPH
5K MSL, 22" MP, 2350 RPM, 127 KTAS, 9.0 GPH
10K MSL, 20" MP, 2300 RPM, 123 KTAS, 7.8 GPH

A gross weight takeoff at 4500MSL on a 90 degree summer day uses up about 400 feet of asphalt. You can horse it off earlier if you use "unconventional" technique. There is no weight increase with the STC - but practically speaking, if it will fit, it can carry it - and the hot & high mental stress level is significantly reduced.

Matt

What kind of weight gain are we talking with the O-360 and the Franklin? Is there a max gross increase with the STC, or does it put the squeeze on the useful load?

No cylinder problems. First annual had all 6 compressions at 80/80. Second annual was all 79s and 80s.

Here's the website for ECI: http://www.eci2fly.com/

If I remember right, our total gain in empty weight was about 60 pounds and most of it was due to the CS prop. Unfortunately Franklin does not have a gross weight increase available with the STC. They should.

M

Is the max gross weight restriction on aircraft to prevent pilots from overloading an underpowered aircraft, or is it an engineering limit of what the structure(wing) is capable of?

zane wrote:Is the max gross weight restriction on aircraft to prevent pilots from overloading an underpowered aircraft, or is it an engineering limit of what the structure(wing) is capable of?

I would bet it's a performance issue, like you said, due to being underpowered.

By 190 horse 170, I assume that you're referring to one with a Lyc O-435 like what came in the Stinson L5. From what I hear, you'd do well to stay away from those. They're heavy for the horsepower, parts are scarce, etc. The other 3 would be much better choices.

Eric

Zero-

I know XP Modifications offers an STC for 195 HP with an IO-360, I think that would be an awesome choice, and since I am in the market for a 170B, I may go down that road in the future, since I want to do my own conversion.

Question:

What is the tuning difference between 180 HP, 195HP, 210HP IO-360's?

Check out http://www.xpmods.com

Got a note from our 170B Franklinstein guy this morning. It reads:

Today I used a stop watch, from a stand still on the runway to 3,000 feet AGL, it took 2 min & 29 sec. Can anyone top that (with a single engine airplane, of coarse). Brian's Mustang II is the only one I think can beat it.

Wow! Our field elevation here at BRD is 1250 and the temp last night was 60 F with little wind.

Brad

I think I can beat that in my Franklin powered Maule.

Wow, my first time here and everyone is talking Cessna 170's. I want one so bad as Zane does. After reading Mike Vivions article in waterflying I think it would be the perfect seaplane for me.