I'm thinking about pulling the starter, alt. and battery on my underpowered cessna 120 hoping to gain some performance for the back country. It would be at least 55 lb lighter. It's 85hp and prop is a climb. Any thoughts?

Taildragger1783 wrote:I'm thinking about pulling the starter, alt. and battery on my underpowered cessna 120 hoping to gain some performance for the back country. It would be at least 55 lb lighter. It's 85hp and prop is a climb. Any thoughts?

That's nearly 4% of your gross weight. And it's a higher percentage of your weight if you don't typically fly at gross. You'll notice.

You could first try by comparing performance at full and half tanks.
That's about a 75 pound difference.

A Gill 25 battery is about 23 pounds. I didn't realize the starter was so heavy as well.

Will you still be in CG with 55 pounds less in the nose?

A friend of mine put his C120 on a severe weight loss program a number of years ago, and wrote up the results for the C120/140 Club newsletter. It weighed close to 950# when he started. He pulled the generator, starter, battery, lighting, and all wiring. Pulled the gyros & venturi. Stripped the paint. Replaced the metal prop with wood. Replaced the t/w with a smaller one. Replaced the heavy interior panels with some super lightweight material. Kept a lightweight 720 com, an intercom, and a small 12 amp motorcycle battery to run them. The final weight on "Fat Free" was right around 850#.

The turn and bank gyro might be part of the type certificate...

Are those 8.50s on your 120? Did you get a field approval for those? I'm trying to decide between 8.00 or 8.50 for my 140A. The 8.00s are approved but not the 8.50s

Taildragger1783 wrote:I'm thinking about pulling the starter, alt. and battery on my underpowered cessna 120 hoping to gain some performance for the back country. It would be at least 55 lb lighter. It's 85hp and prop is a climb. Any thoughts?

How much experience do you have hand propping your plane? Are you comfortable doing that all the time? That may be a bigger deal than you think. Or not. I'd try propping the plane every time you start it for a month to get a feel for it....and no cheating.

The pull type starters on those things and the generators are massively heavy mothers. An alternative might be to replace these with lightweight units and go to a Odyssey or Earth X (don't ask, don't tell) battery. Then work on the interior to lighten it some.

Do you have radios you don't need? If you strip the electrics, are you going to go no radio? If not, you'll still have to use a battery......

Another option would be to pull the generator and that heavy starter, install a lightweight starter, and light battery.....no alternator. More than a few starts, prop it, recharge the battery when at home.

Lots to consider.

MTV

I thought about doing the same on a Luscombe. I ended up not doing it because even after a good preheat it was hard to hand prop in the winter. If you don't have to deal with winter then it might be a good but kind of extreme option. I think a light weight starter and alternator with an earthx battery would be a great way to go.

As far as performance difference...yeah 50lbs would be noticeable.

I would definitely lighten it up.

The planes I learned to fly in had almost nothing but a good parking brake, an oil pressure guage.
Most all old CHAMPS could easily fly by sound alone. That was back when we carried a road map and used water towers as VORs. Flew most of Calif. that way for years. Always had a moving map out front.

One day another partner came up with a heavy little box which was mostly an old lantern style 6 v battery, and on-off switch. and two crystal that had to be switched out another runway. Hell to ya if you dropped the little 1/2" square crystal somewhere under the floor boards.

IMPORTANT thing is to fly the same route over and over so that you could do it in the dark.

If there was any pavement i would pull carb heat on, set the switch to left mag. only, and throttle full of,
Course I KNEW the right amount of blades to pull as "prime" Also had a chock on a rope tied too the front seat frame. At first it would sound like it was going to puke and die with the stuttering on the left only mag.I would quickly punch off the carb heat, switch to both mags, and climb in

So - this old age of 76+ nostalgia wants to make simpler times the best times.
Hell you could actually do an engine compartment pre-flight with those big cowling doors.

Trim

Going in the back country light on fuel is an option, however I live just far enough away I have a few gallons used when I get there. a couple of my friends go full and carry 5 gal plus for each of there planes, so I'm not sure how well that will work for me. But maybe .

MTV

Those are all great thoughts! Matter of fact I have been hand propping it for several years,I almost never use the starter because the a abendix drags also it has a generator it doesn't keep up with very many starts and much radio use. And your right about needing some power for a couple instruments and have considered a small 12volt battery similar to that in a street bike...oops did I say that.

In that case, first thing I'd do is consult the Type Certificate to see what equipment is required. I doubt that an electrical system is "required equipment" on that plane, but.....

Then, visit with your mechanic. When removing some of that stuff, you're going to have to install block off plates, etc, and this will all need to be signed off, and a new weight and balance calculated.

Good luck.

MTV

I don't know if this is doable or applies, but according to my son the engineer (actually, both sons are engineers, so No. 1 Son), a significant amount of weight could be saved if the pilot would go on a diet. He's right. I'd still be pretty healthy if I knocked off 35 lbs.

As those here who've camped with me know, I tend to be a glamper--I pretty much carry the house with me. Also, my airplane is pretty well equipped for a P172D, and all that weighs, too. So instead of trying to pear down all that, when I'm going to go into a relatively short, high DA strip, I plan my fuel to be sufficient to get in there fairly light and go out to the nearest refueling stop with a safe reserve. For instance, from Greeley to LaGarita via LaVeta Pass and Alamosa, it's about 2 1/2 hours, and I stop at Alamosa for a potty break before going on to LaGarita. My airplane holds 52 gallons, with 5 unusable in level flight, 10 unusable in maneuvering flight. At 9.8 gph average, I figure I've burned 25 gallons by the time I land at LaGarita, leaving me 27 - 10, 17 gallons to safely fly back to Alamosa 37 miles away with still more than an hour's reserve. I could probably get away with even less, but it works out pretty well.

I think paring the weight as you describe, or as MTV suggests, isn't a bad thing, but for me, I like having the electrical system and electric starter, as well as my avionics. I haven't hand-propped this airplane, although I've hand-propped several others years ago. I've never been "bitten" by hand-propping, but frankly, I just don't like to do it, no matter how safely it can be done. To me, it's an emergency issue if it's necessary. To some extent, my airplane was put on a diet when the engine was installed, as I had an alternator conversion and light weight starter installed--and I believe that saved something like 26 lbs--both were heavy clunky ol' things.

Just my 2c, FWIW.

Cary

Whee
I see your from SE idaho, where at, Pocatello? I'm from hailey. And I keep my plane in Carey.

Littlewheelinback

The tires are STC'd but they're not 800's or 850's they're AK Bushwheels,air streaks 26" I did find an STC for 800's but couldn't find one for the 850's, but that's not to say there isn't one.

An additional problem with pulling the electrical system: can't fly at night. While that's not much of an issue in the summer time most of the time with longer days, I can think of many times nonetheless when I completed a flight after dark, and it happens frequently in the winter.

Cary

Taildragger1783 wrote:Whee
I see your from SE idaho, where at, Pocatello? I'm from hailey. And I keep my plane in Carey.

I live in Idaho Falls. Used to frequent Cary quite a bit when I was commuting to Boise. Great place to base out of.

Taildragger1783 wrote:Littlewheelinback

The tires are STC'd but they're not 800's or 850's they're AK Bushwheels,air streaks 26" I did find an STC for 800's but couldn't find one for the 850's, but that's not to say there isn't one.

There is no STC for 8.50 tires on most of the Cessnas. But, there is a letter to Steve Kracke at F. Atlee Dodge from the Alaska Region Engineering office of the FAA stating that installing 8.50s on most Cessnas is a minor alteration. I'd take a copy of that letter to your mechanic and see if he'd sign it off with a copy of the letter in the records. I have an electronic copy somewhere if you need it.

MTV

That is something to think about.

Thanks MTV!

Crustation aviation
The tires are AK bushwheels air streak 26"ers