C-170 Aiplanes With Cont.IO-360 Engines

[Ryan Smith]

Hello guys,

This is my first post here, and I'm just posting out of curiosity. My family owned a 1952 Cessna 170B (N2256D, SN20408) essentially since I was born (I'm 23), however due to the lack of us flying and me being fairly involved with model airplanes, my father sold here in October of 2008. I'm working like hell to be able to buy the airplane back, as to me it's not just any 170, I've got a very big attachment to it.

I have wondered about an IO-360 conversion on a 170, and after having joined forum here (I need to join TIC170A, although it feels awkward with no airplane!), I realized I wasn't the only one with this idea. Forgive me if this has been stated previously, but what would be the weight difference between the same airplane in these two different configurations? If it matters, our airplane had a C-145, I'm not sure if that engine is any different in weight than the O-300s. Would there be any feasiblity in using a composite prop and something like a Sky-Tec starter to reduce the weight down a little? My worry would be that this conversion would eat up too much useful load and you'd end up with a hot rod for two people and light baggage. My wife and I don't have any children yet, but I would like to be back in possession of the airplane beforehand, and be in possession of it indefinitely. I'm not looking to make it into a 180, but a little extra speed would be nice, and I can't stand Lycoming conversions on 170s, not to mention the Continental 6s sound awesome!

Thank you for your input. I look forward to becoming more active on here, and maybe I'll run into some of you guys at a flyin or something.

Regards,

Ryan

[Bruce Fenstermacher]

Ryan

Legality will keep you from using a composite prop no matter what engine you have. Installing an OI360 just for a little more speed is, well to be blunt, not money well spent IMO. Spend the money on gas and fly it a bit longer. Most folks want more power to lift and climb with weight at a higher rate and at higher altitudes, and of course some of them go a bit faster.

I need to join TIC170A, although it feels awkward with no airplane!

No need to feel awkward joining the association without an airplane. I'd be surprised to find more that half the members of the association actually own a 170. They may have at one time, just like you, they might be looking for one, just like you, or they may have one that they pretend IS one. (We enjoy the pretenders company as well)

[edbooth]

Ryan , if propeller weight is a big concern to you, Mt propellers has STC's for lighter weight props. They are wooden blades covered with composite material with Metal leading edge protection. They are about half the weight of McCauley metal props...and about twice as much $$$.

Ed Booth, Trenton, SC

[KS170A]

I'm also wondering what "real-world" numbers are with the IO-360 Continental conversion. My neighbor is trying to convert me into a 180 driver, and the weight-to-power ratio seems much better with the earlier 180's than the 170. But a IO-360-equipped 170 is better than the stock 180, in weight-to-power terms. Anyone care to share how much of a weight penalty there is with the 360 & c/s prop? For what I want to do (back-country flying/camping), a heavier empty 170 won't do but I do love the 170.

[GAHorn]

Here's a chart depiction of the various dry weights of TCM engines. The difference between the O300 and the IO360 is about 75 lbs. A CS prop and gov will add another 50 lbs, approx., so the entire conversion probably adds about 125-150 lbs to the empty wt.

TCM Eng Table.pdf

(39.68 KiB) Downloaded 237 times

[minton]

Ryan,

There is also the problem of obtaining a IO-360 Continental conversion kit for a 170B. They are as scarce as "Hens teeth" as a kit.

[futr_alaskaflyer]

There are folks working on a new STC for a IO-360 conversion for the 170 up here. My A&P's 170 is one of the testbed planes, being currently flown under the restricted category pending FAA action, post testing. They hope to hear something soon.

I wish I had more particulars but I know there are a few differences from the previously-popular STC you seen in most converted 170's. A different submodel of the IO-360 and something about dual fuel pumps eliminating the need for a header tank (see, I don't remember what I'm trying to talk about )

edit: to be clear this will be an injected 4-cylinder Lycoming not a Continental.

[blueldr]

It is my understanding that "Tailwheel Tom" (Tom Andrerson) has regained possesion of his previously owned STC for the installation of the Continental IO-360 engine in the Cessna 170 series of airplanes. Since he is now apparently located in Wenachie, (SP) washington, he must get his PMA moved from Arlington, Wn.
to his new location in order to manufacture the engine mounts. I'm anxiously waiting to see what transpires.

[Green Bean]

Wenatchee, WA

[jamyat]

Continental seems to have problems reporting the weights of their engines. The table in the pdf file gives the dry weight of the O300 as 248.7 pounds. The overhaul manual says it is 268. It's not clear whether any accessories are included with the engine. The overhaul manual lists in table II "Purchased Accessories" and lists the mags, starter, generator or alternator, and carburetor. Table VI lists the weights of the accessories and they total 51.8 pounds. So it appears that the C145/O300 should weigh about 319.8 pounds if the accessories are not part of the dry weight of the engine.

The table in the pdf file says the weight of the IO360 is 327.25 pounds. This agrees with the weight in the operator's manual for the IO360. However, the manual is very clear. This weight includes the lubrication system, accessory drives, starter adapter, intake system, mounting brackets, two pendulum type dampers, 12 spark plugs, 2 mags, ignition assembly (wiring harness?), starter, alternator, voltage regulator, and oil cooler.

The McCauley constant speed prop weighs 15 pounds more than the prop for the C145. The prop governor weighs 3.5 pounds. There are some other accessories the C145 doesn't have like a vacuum pump,a boost pump, and a header tank. The 35 amp battery is a few pounds heavier. So it looks like the conversion should add between 50 and 75 pounds to the empty weight. My airplane weighs 1355 pounds. Unfortunately, we didn't weigh the airplane before we removed the C145 so I don't know exactly how much the conversion added.

I really like the IO360. It starts easy hot or cold. It is really loud during take-off and climb, but may be a little less noisy than the C145 in cruise since I turn it 2350 in cruise. My airplane cruises between 145 and 150 mph depending on load and altitude. Its best altitude for speed is about 7500. Cruise power at 7500 feet is about 62%. Climb depends on load and density altitude, but my airport is 1200 msl and the plane climbs 1200 to 1600 fpm. I have seen on a cold day and lightly loaded, 2000 fpm. I flight plan 7.5 gal per hour. I have had some on this forum question my numbers about cruise speed and economy, but those are the numbers I get.

My conversion is not Tom Anderson's STC. My mechanic friend has a one-time STC that we used.

[SteveF]

I know I will be sorry for doing this but:

Blueldr there are three airports in the Wenatchee WA area so could you tell me the identifier code for the one where Tailwheel Tom is located.

KEAT Wenatchee, WA, USA Pangborn Memorial Airport
27W Leavenworth, WA, USA Lake Wenatchee State Airport
WN17 Wenatchee, WA, USA Hoverhawk Ranch Airport Private

[GAHorn]

Continental seems to have problems reporting the weights of their engines. The table in the pdf file gives the dry weight of .... The overhaul manual says ...The table in the pdf file says the weight of the IO360 is ..the weight in the operator's manual ....

Since the TCM pdf table lists ALL the engines dry weight, and presumeably uses the same criteria/def'n of "dry wt".... wouldn't that be more accurate of comparison than attempting to correlate data from the pdf-table vs an "overhaul manual" vs an "operators manual" for a different engine model? (In other words, I think TCM probably used the same criteria for each engine listed in the same table and therefore, for comparative purposes, that table is probably the best source for comparison.)

Your suggestion as to the different wts between the props is not easily comparative, as there were several different props available for the C145/O300 and still more variance if the crankshaft-flange were different due to the C/D engines. (Another reason TCM used dry-wt in their table.)

Excellent points about the rest of the comparison, especially as regards the battery upgrade, etc., which I had not considered.

[hilltop170]

I would suspect the 35A battery would be moved to the tail to off-set the weight difference. A gross wt. increase STC would be most useful.

Empty wt. of 1355lb. is not bad at all considering my "stock" 170 with an O-300-D weighs than much.

I sure would be interested in the conversion if fuel consumption and airspeed increase numbers are as-reported.

[GAHorn]

It will probably be the final-nail in my originality-coffin in another 800 hours or so on the tach.

[Bruce Fenstermacher]

It will probably be the final-nail in my originality-coffin in another 800 hours or so on the tach.

Do you really think so?