Franklin Conversion: Should I?
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Steve, I was in your position for a while until I put everything into the economic equation. While I still have 900 hours to go on my O-300, I wanted to do the research now. When all the dust has settled from an engine conversion in my 170B, I will have invested enough cash to place me squarely in the lower half of the C-180 market. This is not even factoring in the cost of downtime for my 170B. In a purely economic sense, I cannot justify paying more for an airplane that in the end will have a lower gross weight and lower cruise speed. When and if I feel the need for an aircraft with more power and speed, I will enter the C-180 market and get a higher useful load as a freebie! Another thing to consider is resale. If you do decide to convert your 170B, you may loose a large part of the market. When I was looking for my 170B, I did not even consider the converted aircraft with $55K to $65K price tags. The median price of $35K for a 170B with standard O-300 was much more attractive. Just some more things to think about!
John, 2734C in Summit Point, WV
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Dave Clark
- Posts: 894
- Joined: Mon Apr 22, 2002 6:25 pm
Thanks Steve.... if this works you guys can see my install progress as of last week. It should run next week.
Last edited by Dave Clark on Fri Feb 21, 2003 1:53 pm, edited 1 time in total.
Dave
N92CP ("Clark's Plane")
1953 C-180
N92CP ("Clark's Plane")
1953 C-180
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Here goes again. I think I sucessfully copied the one digital picture I have of my plane onto the supercub website.
It is located at
It's not a great picture, but it shows my 170B at my strip at Shell Lake. I'm flying 3000 Fli-Lite wheel skis. For those of you not familar with the heater I'm using, it's a "Northern Companion" that is made in Eagle River, AK (just outside of Anchorage). It's a great preheater and it doubles as a survival stove.
-Rob
It is located at
It's not a great picture, but it shows my 170B at my strip at Shell Lake. I'm flying 3000 Fli-Lite wheel skis. For those of you not familar with the heater I'm using, it's a "Northern Companion" that is made in Eagle River, AK (just outside of Anchorage). It's a great preheater and it doubles as a survival stove.
-Rob
Franklin Conv.
I have a '56 170B with 220 HP Flanklin . I fly it on floats , skis , & wheels . It is a great aircraft . There are no " forward C.G. " problems . It out-performs a Cess 180 in take-off , climb , & speed . Very smooth engine & burns about 11 gph . 10.5 comp ratio demands 100 oct aviat fuel , but that is not a problem (yet ) .
Andrew D.-
planepilot1
- Posts: 49
- Joined: Fri Apr 26, 2002 1:02 am
220 Franklin conversion (Andrew)
A couple of questions: How much useful load did you lose (if any)? What is the fuel burn while out climbing, going faster, etc than that 180? What is the recommended TBO on the Franklin?
Frank Stephenson
franklin conv
my 170B with 220 Franklin on EDO 2440 floats weighs 1,418 LBS . A useful load of 782 lbs , i.e. - 3 persons , full fuel , 56 lbs of cargo . It can easily do that . Basically on wheels , it can get off with anything you can fit in it .
Fuel burn is about 11 gph @ 24 / 24 . I don't think it burns much more at max power , but I always power back to cruise as soon as I get a couple hundred feet in the air anyhow .
On floats , it indicates about 118 mph and on wheels about 138 mph . I flew last summer with another seaplane , cess 180K , he could not catch me . Andrew
Fuel burn is about 11 gph @ 24 / 24 . I don't think it burns much more at max power , but I always power back to cruise as soon as I get a couple hundred feet in the air anyhow .
On floats , it indicates about 118 mph and on wheels about 138 mph . I flew last summer with another seaplane , cess 180K , he could not catch me . Andrew
Andrew D.-
Dave Clark
- Posts: 894
- Joined: Mon Apr 22, 2002 6:25 pm
Had thoughts about starting a new thread for the 180 Lyc but it looks like it's mixed in here enough that I can give my first flight report here. remember this is the conversion that has been underway and I have posted a photo on page 2 of this thread.
I flew it the first time last Thursday late afternoon for about fifteen minutes because it was late and I had noticed the cowl was too close to the spinner at the bottom half. I had about 30 gallons and a 200lb friend aboard. Remember we're at 5000' and it's about 60 degrees out. It had a very noticeable increase in acelleration (sp?) on the takeoff roll, being even much better than if we had been at sea level with the old engine. Our rate of climb after I'd pulled the power back to 75% was in the 700fpm area. In all we had better performance than if we'd been at sea level with the Continental. Perfect! Ended the flight early to check it on the ground. I spent Friday fixing the cowl.
Saturday I flew it twice for a total of two hours. Once alone in the morning and then to take the wife to Sedona for the $100 hamburger. Let me just say that I love it and all the money and time was well worth it. It has made an airplane that is quite usable at elevations and much safer for the mountain flying here out West. That is what I was after. A side benefit is it's about 10++ knots faster where we normally cruise it (at 7-8,000 feet). At 7500 ft cruise and 2300 rpm and 21" mfld press (which is just barely over 65% and 8.8 gallons per hour per Avcon) we were getting over 110 knots on the GPS. I am being conservative because there was some wind, it could have easily been 112 or 113 but probably not 115. Same conditions with the Continental full throttle would have been 100 knots at just over 7GPH. So I guess I got 10+ knots for another 1.8 or less GPH which is not a great tradeoff but..... we cruise climbed (full mains) at about 4-500fpm where the Cont would have been at maybe 300fpm and beginning to really struggle. I had the impression that getting over 10,000ft would be no problem at all with the Lyc so I have yet to figure if in no wind there might be a more efficient altitude but it probably wouldn't matter a whole lot. Plus who cares? This thing is SAFE to fly in these conditions now. That's what I wanted. I'll have to wait to see how it does at sea level but I expect I'll be powering it back soon after takeoff. For me at least the 180 was the perfect engine. For others that have to have a brute the 210 or 220 hp jobs might be the answer.
I did a lot of things to the plane and filed eight 337 forms! It's now 1335lbs empty at 39.36" moment. I lost just over 20lbs useful load with the Avcon, 11 lbs with the Supersoundproofing which is great stuff, and about 24 lbs with the Javelin tank. The CG actually went aft due to the Javelin. Now with 55 gallons of fuel, my wife and I aboard we can carry only 120 lbs of baggage legally. But that's ok I guess because if we acidently
fly it even quite a bit over gross it will be much safer than before. I will say that if we lived back East or never left Puget Sound with it I probably wouldn't have made the change. One needs to match the equipment to the mission.
Other than having to paint the cowling and put in a headliner the plane is about done. The compressions were all fine so it looks like that 1100 hour engine will go for a while. I'll post a photo or two when it's done.
I flew it the first time last Thursday late afternoon for about fifteen minutes because it was late and I had noticed the cowl was too close to the spinner at the bottom half. I had about 30 gallons and a 200lb friend aboard. Remember we're at 5000' and it's about 60 degrees out. It had a very noticeable increase in acelleration (sp?) on the takeoff roll, being even much better than if we had been at sea level with the old engine. Our rate of climb after I'd pulled the power back to 75% was in the 700fpm area. In all we had better performance than if we'd been at sea level with the Continental. Perfect! Ended the flight early to check it on the ground. I spent Friday fixing the cowl.
Saturday I flew it twice for a total of two hours. Once alone in the morning and then to take the wife to Sedona for the $100 hamburger. Let me just say that I love it and all the money and time was well worth it. It has made an airplane that is quite usable at elevations and much safer for the mountain flying here out West. That is what I was after. A side benefit is it's about 10++ knots faster where we normally cruise it (at 7-8,000 feet). At 7500 ft cruise and 2300 rpm and 21" mfld press (which is just barely over 65% and 8.8 gallons per hour per Avcon) we were getting over 110 knots on the GPS. I am being conservative because there was some wind, it could have easily been 112 or 113 but probably not 115. Same conditions with the Continental full throttle would have been 100 knots at just over 7GPH. So I guess I got 10+ knots for another 1.8 or less GPH which is not a great tradeoff but..... we cruise climbed (full mains) at about 4-500fpm where the Cont would have been at maybe 300fpm and beginning to really struggle. I had the impression that getting over 10,000ft would be no problem at all with the Lyc so I have yet to figure if in no wind there might be a more efficient altitude but it probably wouldn't matter a whole lot. Plus who cares? This thing is SAFE to fly in these conditions now. That's what I wanted. I'll have to wait to see how it does at sea level but I expect I'll be powering it back soon after takeoff. For me at least the 180 was the perfect engine. For others that have to have a brute the 210 or 220 hp jobs might be the answer.
I did a lot of things to the plane and filed eight 337 forms! It's now 1335lbs empty at 39.36" moment. I lost just over 20lbs useful load with the Avcon, 11 lbs with the Supersoundproofing which is great stuff, and about 24 lbs with the Javelin tank. The CG actually went aft due to the Javelin. Now with 55 gallons of fuel, my wife and I aboard we can carry only 120 lbs of baggage legally. But that's ok I guess because if we acidently
fly it even quite a bit over gross it will be much safer than before. I will say that if we lived back East or never left Puget Sound with it I probably wouldn't have made the change. One needs to match the equipment to the mission.Other than having to paint the cowling and put in a headliner the plane is about done. The compressions were all fine so it looks like that 1100 hour engine will go for a while. I'll post a photo or two when it's done.
Dave
N92CP ("Clark's Plane")
1953 C-180
N92CP ("Clark's Plane")
1953 C-180
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Congratulations,Dave! You must have a big grin ear-to-ear now! The weight at 1335 is plenty good,considering the bigger engine,soundproofing,and other upgrades. There's a lot of plain-Jane,145 powered 170's around the same weight (like mine).
Did you weight it,or calculate it?
I'll be looking forward to a ride in that bad boy this summer.
Eric
Did you weight it,or calculate it?
I'll be looking forward to a ride in that bad boy this summer.
Eric
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Dave Clark
- Posts: 894
- Joined: Mon Apr 22, 2002 6:25 pm
eric
I know better than to weigh it! Especially with the Lyc because I'm after all the legal useful I can get. And the of course I'll probably sorta accidently abuse it now and then.
Hey, I'M looking forward to that first takeoff at sea level! Even with the 181 when we'd go direct over the high country that first takeoff at sea level was always a lot of fun. A ride? Heck you can fly it.
I know better than to weigh it! Especially with the Lyc because I'm after all the legal useful I can get. And the of course I'll probably sorta accidently abuse it now and then.
Hey, I'M looking forward to that first takeoff at sea level! Even with the 181 when we'd go direct over the high country that first takeoff at sea level was always a lot of fun. A ride? Heck you can fly it.
Dave
N92CP ("Clark's Plane")
1953 C-180
N92CP ("Clark's Plane")
1953 C-180
Well I spent sunday working on the firewall, finishing all the modifications to it so that I can mount the majored Lyc O-360 to it this coming weekend. The engine will bolt up complete; mount, exhaust, accessories and engine baffling. Then the next big thing to do is modify the engine cowling, blisters, new modern nose bowl, oil door. With the engine mounted the nose bowl is centered around the starter ring gear of the Lyc, and the blisters are fitted for the fwd cylinder interference. Starting down the home stretch now. Lance
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Eric ,
I guess I'm pretty slow on this question ( like about 6 months ) . and I 'm now confused . I put my 170 on scales with no fuel and came up with 1550 lbs . ( that is on wheels ) , but my only weight & balance record says 1418 lbs on floats ! I think there is a mistake somewhere .
what do other 170B 's weigh with 220 hp Franklins ?
Andrew D.