CamTom12 wrote:

Cary wrote:

jaudette wrote:No - It's got 38 Usable. About 4 hours endurance which I'm ok with.

Jim

I think with the Franklin that'll be 3 hours 20 minutes total, or 2.7 plus 30 minute reserve. With my 180hp Lycoming, I get 9.8 gph almost constantly. I'd guess you'll be in the 11.5 gph range.

Cary

It takes very nearly the same amount of fuel to make the same horsepower, regardless of the engine.

If you want to dial back the MP/RPM a bit, you can have fuel burns very similar to a smaller engined airplane with very similar airspeeds.

I cruise my 160hp O-320 between ~5.5 and 8.5 gph. Just depends on how fast I want to get somewhere.

In other words, there's no magic behind a smaller engine burning less fuel. A larger engine can do the same.

Oh, I agree completely--but I also know that there's a tendency to use all the horses you have. If I wanted to, I could bring mine back also--in fact, I did that just 2 days ago to see what the airspeed would be at 2200 rpm and 19" MP instead of my usual 2400 rpm and 21" MP. Fuel flow went down to just under 8, but I lost 10 knots. Not that it makes all that much difference, but 105 knots instead of 115 knots means that my flight time to OSH in less than 2 weeks would be 45 minutes longer to save 7 1/2 gallons of gas. Then I couldn't brag about my hot rod airplane's fantastic speed!

Cary

Cary wrote:

CamTom12 wrote:

Cary wrote:I think with the Franklin that'll be 3 hours 20 minutes total, or 2.7 plus 30 minute reserve. With my 180hp Lycoming, I get 9.8 gph almost constantly. I'd guess you'll be in the 11.5 gph range.

Cary

It takes very nearly the same amount of fuel to make the same horsepower, regardless of the engine.

If you want to dial back the MP/RPM a bit, you can have fuel burns very similar to a smaller engined airplane with very similar airspeeds.

I cruise my 160hp O-320 between ~5.5 and 8.5 gph. Just depends on how fast I want to get somewhere.

In other words, there's no magic behind a smaller engine burning less fuel. A larger engine can do the same.

Oh, I agree completely--but I also know that there's a tendency to use all the horses you have. If I wanted to, I could bring mine back also--in fact, I did that just 2 days ago to see what the airspeed would be at 2200 rpm and 19" MP instead of my usual 2400 rpm and 21" MP. Fuel flow went down to just under 8, but I lost 10 knots. Not that it makes all that much difference, but 105 knots instead of 115 knots means that my flight time to OSH in less than 2 weeks would be 45 minutes longer to save 7 1/2 gallons of gas. Then I couldn't brag about my hot rod airplane's fantastic speed!

Cary

What's 2200 rpm and 21" get you? Shoot, at the DAs you fly that's probably WOT! When you descend to OSH, I bet your fuel flow would decrease more with RPM reduction than MAP. Have you tried 2200/24" at lower altitudes? How's that do for speed/fuel burn?

Total thread drift, sorry jaudette!

I can't help but envy your manual flap. I have had my 67 172 H with a 220 Franklin for about ten years now and 800+ hours an airplane that has won the hearts of all that have flown with us.
Mods that I have done and glad I did.
1. JPI 711 engine analyzer with fuel flow, no joke it saved my engine and may be more last year, I had a bad plug that started pre ignition, #2 cyl went into thermal runaway. JPI also interacts with my 496, calculates fuel reserve, very nice to have. XM in the head sets is nice too.
2. Sportsman STOL kit, took 10-15 mph off my bottom numbers, drastically improved low speed handling, the aileron seals that come with the kit reduce much adverse yaw in turns, big improvement in the pattern/every where.
3. BAS harness no improvement in performance, just piece of mind.

Performance: At cruse, I generally run a bit lean of peek on some cylinders, @ 8500 ft 2450 rpm 21 mp = 8.7 gph average on a X country, true is 142-145 mph
If I burn 10 gph I average 152 mph or so. Normal climb out from L05 2614 ft with full tanks and some stuff in the airplane 100 mph 1000 fpm

Advice: the major difference between A Franklin 220 and most other aircraft engines is the compression ratio the Franklin 220 is 10.5:1, never run MoGas in it, many have been destroyed in this manner. Prior to my ownership mine was, burnt pistons, spun bearings, forced landing.
Thanks to the high compression ratio your Franklin will also preform better at high altitudes than other aircraft engines with lower ratios. Look up my thread "why some cams fail" long story, but this is why Franklin's eat cam shafts.
I love these aircraft, the Franklin makes a 172 a joy to fly, OH yea,,, they sound real cool to.
If I can help call me 760-832-2736 Joe

Guy's - Thank you for your comments! I've put only two hours on the plane and I have to say I think this one will work out. I haven't decided everything I'm going to do yet. I know for sure I'm going to put the bigger mains and Airglass front fork and also shoulder harnesses.

I was thinking about VG's, but they don't get you much and might be more of a PITA than they are worth. I've been looking at the Sportsman but I don't know. As it sits, it will get me in and out of any strip I'm going to go into. I guess it would give me some margin.

I'm going to spend the rest of the summer fixing it up and will see where I end up.

Jim

I'm sure it may vary by aircraft, but for the 205, the VGs were a huge bang for the buck. A very noticeable increase in performance. Aopa did a review on a 172 a few years ago and came to the same conclusion. Stall speed drop around 10%+ and increased control effectiveness. Definitely worth the money.


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Grassstrippilot wrote:I'm sure it may vary by aircraft, but for the 205, the VGs were a huge bang for the buck. A very noticeable increase in performance. Aopa did a review on a 172 a few years ago and came to the same conclusion. Stall speed drop around 10%+ and increased control effectiveness. Definitely worth the money.


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I'm not ruling them out, I'm just going to fly it for a while and get used to it before I decide. The sportsman STOL kit is not really all that more expensive (all things relative). Big engine + big wheels + Sportsman STOL =

It's funny, this thing fly's a lot like my Maule. I really like the panel, manual flaps and the smoothness of the engine. I'll take a picture of the panel, but it's basic IFR with two KX-155's. I'm not planning on doing anything with the panel aside from adding ADSB and a cradle for my iPad.

I had my mind set on a 182, but all things considered, I'm pretty happy! I'm taking the rest of the summer and fall off of work to get this thing where I want it and it will be my full time job.

Jim

That's awesome. And I agree. I want both the sportsman and the VGs. A friend has the setup and is consistently seeing 300' takeoffs and landings in his 205. For us, the VGs are almost as important on the tail as they are on the wing just for the added elevator authority since we have the shorter horizontal stabilizer. Sounds like a fun bird you've found!


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Grassstrippilot wrote:I'm sure it may vary by aircraft, but for the 205, the VGs were a huge bang for the buck. A very noticeable increase in performance. Aopa did a review on a 172 a few years ago and came to the same conclusion. Stall speed drop around 10%+ and increased control effectiveness. Definitely worth the money.


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I don't disagree that VGs can make a difference, but for some, it's their flying that needs to modified rather than the wing. Some months after I bought my airplane, which has the stock 1962 Cessna 172 wing (no cuff at all) but with super droopy tips, I was chatting with a hangar neighbor. His was a somewhat newer 172, I think about 74 or 75 or so, with the Cessna mild cuff and VGs. I've flown beau coup 172s with the Cessna cuff but none with VGs, so I asked him what he thought of them. First he told me that they were a pain when refueling--literally, since he'd cut his hands more than once on them. Then he started bragging about the increased performance: "I can make my approaches now at 65 knots!"

Not wanting to burst his bubble, I just said, "That's pretty good." Unfortunately he burst it himself, when he asked what my approach speeds were. I had to tell him that I made most of my final approaches at 70 mph, about 60 knots. He said something about my droopy tips must make that difference, but I told him that although they do make for more positive control, 70 mph or 60 knots is what I've always used for a final approach speed in any stock 172, except in crosswinds or other gusty winds.

But as has been discussed, each airplane is a bit different. 205s and 206s are not 172s or 182s. Similar wings, yes, but significantly different empty and gross weights. So I'd never belittle anyone for putting VGs on any larger Cessna; I just wouldn't expect any significant benefit on mine.

Since that conversation with my then hangar neighbor, I did have flap gap seals installed. I've flown with them for about 12 years, and I can't see that they did anything pro or con for slow speed operations. They did provide an honest cruise speed gain of about 5 mph.

Cary

I have not tried anything different than 2400/21" at lower altitudes except once. I did higher power settings going into OSH, when I was within a gnat's arse of not making it in before the airport closed a couple of years ago (forgot the time difference, and thought I still had more than an hour and 15 minutes when I actually had only 15 minutes). At 2700 rpm and full throttle (don't recall what the MP was, but close to 30 probably), my little airplane "leaped" ahead to about 125 knots (130 once I started downhill), fuel flow jumped up over 12 gph, tower allowed me to bypass the RIPON/FISKE VFR procedure, and as I touched down on 36 left, I heard "Good job, Cessna. Welcome to Oshkosh. Attention all aircraft, Wittman Field, Oshkosh, Wisconsin is now closed."

Cary

Lots of Frank guys on here with great data. I'm sure you've already heard it, they like RPM.
My 165 hp and 220 ran nicely at 2550.
Generally never lower than 2400.
Never killed a plug, cylinders trouble free.
Chaz

Chazdevil wrote:Lots of Frank guys on here with great data. I'm sure you've already heard it, they like RPM.
My 165 hp and 220 ran nicely at 2550.
Generally never lower than 2400.
Never killed a plug, cylinders trouble free.
Chaz

The TBO is 1,400. What did you get out of yours? I spoke to a frank engine builder yesterday and he said pay no attention to TBO. He said run the engine... Before I bought the plane I spoke to three engine builders who said they had the parts to re-buil the engine now.

Thoughts?

My spare 220 has something like 1960 hours SNEW, and I don't see anything in the logbook saying it's even had a top overhaul. Compressions are still good. I suspect it was removed because the owner figured going 500+ hours past TBO on an "orphaned" engine was good enough and he upgraded his M5 to an O540.