The International Cessna^® 170 Association

Has anyone got any data regarding the difference in weight between a C-145 installation and a IO-360 installation with a fixed-pitch propeller? There were some numbers that didn't quite correspond from one engine to the other that were posted in another thread a while back. I'm looking for a ballpark estimated weight increase from Continental C-145-2H to a fixed-pitch IO-360 installation with vacuum pump, header tank; legal, ready to fly. If it's a 30 pound net increase, I'd be interested...if it's a 125-150 pound increase, I'll go on a diet and fly from longer runways on cold days.

I enjoy the simplicity and light weight of the 170, thus my interest in keeping an IO-360 installation as light as possible over the stock form. While the performance of a constant-speed propeller is nice, I don't NEED one in a 170. I simply want more climb performance on a hot day when I'm heavy, and I don't want to sacrifice cruise speed or add a bunch of weight do accomplish this. Furthermore, with the IO-360 still being installed in one of the most popular light planes in production now, I would prefer a more modern powerplant (not that there's anything wrong with the C-145), but I don't want parts availability to become an issue. It's already difficult enough to find airframe parts...I don't need to compound that with engine parts.

As N2256D sits today, she's just a shade over 1300 empty. If I could go to 1350 or a little over and have more power, I'd be a happy camper. If this is a fool's errand, then I'll stop daydreaming and look at a Bonanza or something instead.

The header tank and plumbing won't add but a few pounds at best.

Without the governor and a light weight starter, I'd bet the weight difference is less than a Christmas ham.
if you don't need the vacuum pump, that could make it even less.

If you go that route, I have two fixed pitch props that will fit the TCM IO-360. One needs the tip repaired due to a shipping incident.

[quote="Ryan Smith"]Has anyone got any data regarding the difference in weight between a C-145 installation and a IO-360 installation with a fixed-pitch propeller?

There is a lot of information on the Swift web forums concerning this question. The issues they have installing a TCM IO360 are similar to that of installing in in a 170. Also read the info you can find on the web concerning the IO 360 in the T41B the US Air Force purchased the originals with a fixed pitch prop. It created problems for Cessna which were never resolved until they installed a constant speed propeller. Information about that is pretty detailed in the T41B section in the book Cessna Wings for the World by William D Thompson. It covers the story of the single engine development by Cessna a good reading even if you do not want developmental information about the single engine Cessna’s. There are two other books by William D Thompson. Book II & III that are not the same book. Read this review. http://www.eaa1000.av.org/related/bookrevu/cessna.htm. After doing my research I would never consider running a fuel injected engine without a constant speed propeller.

Ryan Smith,
When I did my conversion to the TCM IO-360, I bought two FP props from a guy down in OK. They were off of a Model of the cessna T-41. One was pitched 75 X 50, the other was 76 X 60. The 50 in. pitch was a little too thin and allowed too many turns static and spun like hell in climb and cruise. The 60 in. was just right and I would have been well satisfied with it if had I not tried to fly from my home here in CA to the fly in in Recklaw, TX. That long XC trip convinced that I needed a CS prop, and it so happened that a friend of mine with a C-182 had just switched to a three bladed McCauley and offered me his 82 in. CS st a very nice price. I succommed and hung, with the governor, about 35 0r 40 more pounds up front. My opinion is that the CP prop is not needed ubless you're going to be flying a lot of relatively long XC trips.
Sorry, but I can't remember much about weights. The exhaust system was about 5 or 6 pounds heavier than a stock system since there were no mufflers and a heat exchanger shroud on the left side only.
The added nose weight of the conversion was the reason I installed the C-180 LG model with the axle line about 4 in. forward of the C-170 gear.

I don't see why, after spending all that time and money to upgrade the engine, you'd give away performance by installing a FP prop. With 180hp or more up front you'll never notice the extra weight, except when you do the W&B.

DaveF wrote:I don't see why, after spending all that time and money to upgrade the engine, you'd give away performance by installing a FP prop. With 180hp or more up front you'll never notice the extra weight, except when you do the W&B.

If the STC came with a 2500lb MGW increase, I may be more inclined to consider. John Barrett's airplane is amazing and flies unlike anything I've ever flown. The only reason for consideration of this engine is to get a little better performance, and this is just the next rung higher on the ladder. I can afford the loss; I'm affording it now with less horsepower.

If your flying really doesn't need a CS prop, like if you only fly short legs as in the back country of Idaho, a FP is simpler, lighter almost maintenance free and no governor or cockpit controls.
I have a friend with one of the first TCM IO-360 conversions and he's been flying it with the same FP prop for thirty years or more.

blueldr wrote:If your flying really doesn't need a CS prop, like if you only fly short legs as in the back country of Idaho, a FP is simpler, lighter almost maintenance free and no governor or cockpit controls.
I have a friend with one of the first TCM IO-360 conversions and he's been flying it with the same FP prop for thirty years or more.

Thank you so much for your help and information, Dick.

My mission profile wouldn't require a constant speed propeller. The airplane has never had a CS propeller on it, and we've flown it some decently long distances, with our longest trip being from North Carolina to Louisiana before the airplane was sold. The airplane is a bit more of a dog when it's hot and I'm flying at MGW than I'd like, but not enough to completely change the scope of the airplane to accommodate a small change. The fact is, I'm an east coaster, and I don't generally operate out of high field elevations, and the shortest runways I routinely fly into (and would take the airplane into) would be about 1,900 feet. Certainly until my wife and I recover from the shock of aircraft ownership, we may be on the lookout for alternate means of cross country transportation, but for now, I'm focused on getting the 170 and enjoying it for a while. It'll be an all-purpose machine- from hamburger runs to vacation machine.

The pros that I've identified for keeping a fixed pitch propeller on the airplane are:

1. The airplane is getting a 30% increase in power...that alone will translate into enough of an increase in takeoff performance to satiate my desires. The airplane cruises at what it cruises at, and it will never be a Bonanza, if I can get out of where I need to get out of a lot quicker, and pull the power back to cruise at the same airspeed as I normally do, I'll be happy. I'm really just looking for a little better hot/heavy takeoff performance.
2. Simplicity. I don't feel like fooling with another expensive component on a relatively simple airplane.
3. Lower weight. I'm big, I'm not quite 6'4" tall and weigh 300 pounds right now. My lightest that I've ever been as an adult has been about 230, and that was when I was working construction slave labor for my father. One can argue that getting back down to my fighting weight will take care of the difference in the weight of a CS propeller versus FP, but that weight will always be there. I can lose weight as I can/need. Even an MT propeller setup will only be so light, the propeller and governor weight will never go away. I'd rather have the option to replace that weight with fuel or passengers or baggage rather than have it "greyed out", if you will.
4. Oddly enough...originality. I enjoy reading the jabs at George, but I really have taken a shine to his view on originality and what it means to an airplane. I really love Cessna 170s. I like Cessna 180s, but I've got a strong attachment to 170s, and my family's airplane in particular. Even though I fall into the "bullet spinner and air box cowling sacrilege" camp, a CS propeller will require a different spinner, and will alter the look of the airplane to eliminate all doubt that its' been modified. One of the major draws for the TCM IO-360 is that it fits in the cowling with a minimum of modifications, and with a fixed-pitch propeller, even a savvy aircraft enthusiast would be hard pressed to tell that there was a much different engine installed. Furthermore, a prop control is a bit harder to seamlessly integrate into a piano key panel, and I don't think I'd ever own an airplane with a CS propeller without a vernier control knob.

The only pro that I can think of for a CS propeller is performance. One can always optimize the pitch of the propeller, the airplane will be inherently more stable during maneuvering because the RPM never changes, and there is a bit extra adjustment available to optimize cruise power configuration. Again, this is a 170...so oversquare LOP operations are not really in the scope of my use or interest in this airplane.

The bottom line is, I'm a big fan of the engine upgrade. John's probably tired of me talking about getting to fly his airplane for 45 minutes, but it made a huge impact on me, and his airplane is without question the nicest airplane I've ever flown, let alone set foot in. My friend that owns the airport that I fly out of has a Hawk XP that he absolutely loves, and he's been fond of my family's 170 since we brought it to live at W88. He thinks that engine in a 170 airframe would be about the ultimate flying machine, and he's owned about 40 different airplanes over the years from ratty old J3s to brand new Baron 58s.

I can't get the cart too ahead of the buggy as the engine upgrade, if it happens, will be a while down the road. I'm focused on getting the airplane, and it looks like I'll have all of my ducks in a row in about February or so. From then, it will be a waiting game. I don't mean to derail THIS thread, as it's been a wealth of information, and I certainly don't want to detract from your engine conversion. Should Bruce or George see fit, my little tangent would probably be better served as a standalone thread. I appreciate everyone's input and responses to my daydreaming.

Should Bruce or George see fit, my little tangent would probably be better served as a standalone thread. I appreciate everyone's input and responses to my daydreaming. [/quote]
It is still a Day Dream for me even as I do this upgrade? But I have to say until you have flown the 170 with an 80-42,43 prop you are not getting 145 horse power out of the 0300. Mine goes slow with it abut 100 MPH but it is in my opinion the best option short of 180 HP or more. I like my 170 but I am not an originality guy. If It were 1952 and I were getting a 170 and I could afford upgrades like more HP that is what I might do. With all of the instrument panel upgrades virtually a glass cockpit in the Cessna P210 I maintain, Inter-cooler etc etc. I can just imaging some one in 30 years trying to return it back into it's original as delivered configuration. It is just not reality of owning that type of airplane. I do not want the fuel consumption of a 180. Unless I win the Lotto. Just day dreaming. Everyone I fly with out here is excited about my engine mod, especially my friend with the 180 HP tail dragging 172. I can hardly wait. But work gets in the way.
This thread for me is just for fun
Dream On
Jim

I'm interested to hear how you end up doing your exhaust.
The STC is vague enough with the 'cut to fit' or 'modify as needed' but that turns into a lot of cutting, fitting and modifying.

The guy building mine mentioned using the headers of the rear of a 337 or 336 and seeing if he could drop the exhaust out the original holes.
Not sure about how he'll get that approved tho.

In one of the above comments, someone mentioned the word "approval"about an exhayust system on tje C-170 modification installing thr TCM IO-360 on the Cessna C170b. The pictures of the exhaust system of mine that Johneeb posted were duly approved by me. It worked great and that was good enough "approval" for me.

Anyone considering, or in the process of, Installing a TCM IO-360 in their C-170, Check n the Trade Mart section for an exhaust system that's available.

Quick update on my project ( I dont think it's worth creating a whole new thread).

Mount is done. Prop is re-indexed and ready.

The case on the motor was split and the crank checked out fine, despite the prop-strike. But it's an Airmelt so it wont go back in anyway. We're looking for a serviceable crank now.
We also fount a broken thru bolt that caused one of the main bearings to chatter and wrecked the bore. Already have a new case lined up.
Everything else checked out fine and we hope to have it back together by Christmas.

Still working on the exhaust not fitting and looking into options. We really want to use the Hawk XP setup if possible but not without some cutting and welding.
I'd really like to but the 337 headers and a 2 into 1 Y pipe but that will be more tricky to get approved.

I don't have any photos as all the work is being done remote from my location. That'll drive my price up (labor) but it was the only way for me to get this done.

Aryana wrote:Some progress every week/month and eventually you'll be done! How far away from your home base is the work being done?

Right now, about 600 miles over in Michigan. Once the motor, mount, exhaust and brackets are done ill ship everything to Pittsburgh where I have a hangar lined up. That's only 200 miles away

http://www.ebay.com/itm/BEECHCRAFT-BONA ... 2c&vxp=mtr

I wonder if those would work and what it would take to get approved.