Fuel Tanks

HC Smith III · Post by **HC Smith III** » Mon Jan 24, 2005 12:30 pm

Greetings

Ive posted this question on the International 120/140 site, but I'm checking all avenues. Does anyone know if a Cessna 120 with fabric covered wings can accept Cessna 170 fuel tanks as utilized in the 1948 Model 170? Very good friend of mine has a 120 that is about to have the wings recovered, he has asked if it is possible to put in larger tanks. Does anyone know if this has been done on the 120 or 140 type aircraft with the fabric wing. We know that the 140A can accept the longer range tanks. Thanks

Post by **Bruce Fenstermacher** » Mon Jan 24, 2005 2:38 pm

I'm sure others will chime in but I believe the tanks in the '48 170 are the same as the 140. Don't know about the 120.

mrpibb · Post by **mrpibb** » Mon Jan 24, 2005 5:03 pm

The 1948 170 has three 12.5 gal fuel tanks, there are two in the right wing combined together to make 25 gal, and a lone 12.5 gal tank in the left. And as far as I know the 140A has a different wing, more like a C150 without the fowler flap which would give a greater wing cord and space between ribs to accommodate a larger tank as opposed to the constant cord 120/140/48'170 wing. I do not know if anyone has put the dual tank setup in a 12/140, I know that people have put dual tanks on the left side of the 1948 170's which is kinda the process of what your looking to do. So to sum up what I think I'm trying to say is that you will have to duplicate the 170 fuel tank set up which would yield about 33 gals usable.

Cheers

HC Smith III · Post by **HC Smith III** » Mon Jan 24, 2005 5:50 pm

Thanks Bruce and Vic,

I'm sure that the fuel bay area in the 120 wing will not accept the addition of another tank unless modification is performed and approved to the structure. I know that there is an issue concerning the anti-drag wires in the 120 wing. In order for one to mount additional tanks, the structure would more than likely have to be modified by moving the rib outboard of the fuel tank as well as moving the anti-drag wires which I don't think is going to fly with the FSDO. Personally I think that trying to put bigger tanks as in the 170A or B in the 120 wing would be a major undertaking. What we were hoping for is that someone may have already accomplished it, and would be willing to share the "how they did it" information. My own aircraft is a 140A for which the wing can accept the longer range type fuel tanks than the standard units in that airframe. I'll check back on the site tonight to see if anyone posts anything differently.

Thanks

Mike

zero.one.victor · Post by **zero.one.victor** » Mon Jan 24, 2005 6:58 pm

Guess I'll chime in too.The ragwing 170 has three 12.5 gallon tanks, like a lot of others mine has a fourth added. As far as I've ever heard, they are the same as the 120/140 tanks. I've never heard of any "long-range" tanks for the 120/140 other than the (40-gallon?) "patroller" tanks for the 140A. But that sure doesn't mean it's never been done! You might check the wing-rib spacing, it might be possible to install extra outboard tank(s) ala the 48 170. FAA sign-off might be a problem, though. The extra fuel would sure be handy for longer flights, or if the 120/140 had a Lycoming 290 installed.
I don't have mine here at home, but you might check out the 170 IPC for a drawing of the wing structure, and see how they fit the outboard tank in there. Then compare that to the 120/140 wing, a similar installation might be possible.

Eric

zero.one.victor · Post by **zero.one.victor** » Tue Jan 25, 2005 5:13 am

I looked up the fuel tank info in my 1948 IPC. The LH tank is p/n 0522612, the RH inboard tank is p/n 0522613, and the RH outboard tank is p/n 0522614. I don't know what the p/n is for the added 4th tank (LH outboard) that alot of us (including me) have installed-- there doesn't appear to be any logbook entry or 337 for this mod. Musta been factory issue-- right?

Mike, I'm curious if the part numbers for the 170 inboard tanks are the same as for the 120/140 tanks. The outboard tanks have no filler caps. It'd be interesting to know what p/n the added LH outboard tank is-- maybe a LH inboard model with the filler neck welded shut? Anybody have the p/n for this added LH outboard tank from their paperwork?
I also looked at the wing structure drawings. It showed that the #2 rib was omitted from each wing to install the inboard tank,& the #4 rib was omitted from the RH wing to install the outboard tank. The anti-drag wires start at the #5 rib of each wing & go outboard from there. Maybe the 120/140 wire installation is similar, and you could make room for an extra tank by removing the #4 rib.

Eric

N2540V · Post by **N2540V** » Fri Jan 28, 2005 6:42 pm

Eric,
I have no idea for the part number for the 4th tank
My repair and alteration form says
"installed aux. fuel tank in left wing exactly as aux. tank was installed in right wing.

This documentation is confusing when it says that they removed item #303 from left wing and installed #304 in both wings.
Jim

zero.one.victor · Post by **zero.one.victor** » Sat Jan 29, 2005 7:03 am

I wonder if they're referring to the TCDS: "item 303: landing light, Grimes D-3040-8 (Cessna dwg. 04220007), 6 lbs. item 304: landing light, GE 4509 (Cessna dwg. 0523000-2), 2 lbs"
Sounds like item 303 is the fold-down landing light, and item 304 is a leading edge landing light (dual or single?). Then that logbook/337 entry seems to make sense. But you'd think they would identify the parts by name as well as by TCDS item number. Oh well, at least they logged the modification, even if it was in a confusing manner.

Eric

zero.one.victor · Post by **zero.one.victor** » Sat Jan 29, 2005 4:44 pm

I got to thinking about this-- as I recall, 4509 is the p/n for the lamp itself, not a landing light assembly. Checked my catalog, yup I was right. So i figured maybe item 303 was the fold-down landing light assembly, & 304 was the lamp itself.
BUT, the TCDS shows item 303 located at station +44" on the ragwing, and item 304 at station +32" for the A & B. So I was right the first time, item 304 is the leading edge landing light assembly. I assume that's the two-lamp assembly, as I've never seen a single-lamp leading-edge light on a 170.
If someone installed 2 two-lamp landing lights, they musta been serious about wanting to see at night!

Eric