Cessna 170 on floats

[hbcroft]

Hello folks

I currently own a Citabria 7ECA. Love it and beautiful time builder but I am looking at upgrading eventually. There is a nice Cessna 170b powered by the o-300 cont not far from here that may be for sale in the near future. Would that make a decent 2 persons float plane? I live in Fort Smith, Nortwest Territories right at the edge of the Canadian shield. Lots of lakes and elevation varies from 600 - 2500 asl at the most. So quite a float plane friendly area...

Any advice...

Cheers

Bruno Croft
Ft Smith, NT

[flyguy]

I have a little time in a 170B on floats and can tell you that at standard (59*/sealevel) the plane is a an OK two-place. Any combination that puts the plane close to 85% of gross weight or higher temperatures or altitude (density or other) will need lots of water and the right conditions to get airborne. I love the look of one but avoided giving in to the urge to put mine on floats when I lived on a lake in northwestern Missouri.

These limitations are directly related to marginal horsepower. At only 145HP (less on older engines!) the 170 has a struggle flying at book numbers. They are not only difficult to get airborne but cruise much slower than one with wheels. A 170 with higher HP would be a different breed of cat, but then you get into the price range of a 180 on floats.

[zero.one.victor]

There's an STC'd "borer"-type prop available,McCauley 1A170DM 8043,approved for 170's on floats & wheels. I understand it makes a hell of a difference for TO & climb,but of course you give up some cruise ( unless you don't mind running at redline!). A guy I know has one on his wheel-plane & likes it.
Trouble is,they list for like $2500 or $3000 new & they're pretty hard to find used. The few I've heard about that were for sale were all in Alaska. Kenmore Air Harbor in Seattle has the STC.

Eric

[mit]

I have over 400hrs flying my 145hp 170-B on floats. If I had the money I would get a Cessna 180 or 185, or at least 180 hp lyc. conversion.
I have flown thousands of pounds of exterior loads full sheets of plywood 2x4's, counter tops, 32 ft extension ladder, preframe door, I have been wishing I had more Horse Power for along time!

Hello folks

I currently own a Citabria 7ECA. Love it and beautiful time builder but I am looking at upgrading eventually. There is a nice Cessna 170b powered by the o-300 cont not far from here that may be for sale in the near future. Would that make a decent 2 persons float plane? I live in Fort Smith, Nortwest Territories right at the edge of the Canadian shield. Lots of lakes and elevation varies from 600 - 2500 asl at the most. So quite a float plane friendly area...

Any advice...

Cheers

Bruno Croft
Ft Smith, NT

[flyguy]

[quote="zero.one.victor"]There's an STC'd "borer"-type prop available,McCauley 1A170DM 8043,approved for 170's on floats & wheels. I understand it makes a hell of a difference for TO & climb,but of course you give up some cruise ( unless you don't mind running at redline!).

Eric[/quote]

If you had a four speed standard transmission in your pick-up truck would you be willing to drive in only "granny"gear all the time? That is what a "43" prop does. Cruise speed, if that is what one can call it, of 80mph is not very efficient. A J-3 on floats will almost keep up with that! I'm with the post above and if I had the money I would go with a 180.

[N3243A]

Flyguy,
Using the analogy of flying behind a 43 pitch prop as being in "granny gear" all the time is the same as saying that flying behind a 55 pitch prop is the same as being in 4th gear all the time and "lugging it" to get out short or steep. Either way has trade-offs, depends on your mission profile. Were both fixed pitch, period. The trade-off for a 80-42 prop is not 80 mph, either. You can expect 100 mph cruise with one.

Bruce Christie

[mit]

Flyguy,
Using the analogy of flying behind a 43 pitch prop as being in "granny gear" all the time is the same as saying that flying behind a 55 pitch prop is the same as being in 4th gear all the time and "lugging it" to get out short or steep. Either way has trade-offs, depends on your mission profile. Were both fixed pitch, period. The trade-off for a 80-42 prop is not 80 mph, either. You can expect 100 mph cruise with one.

Bruce Christie

I sure don't get 100 with my 80/40, floats wheels or skis.

[zero.one.victor]

From what I've heard,on wheels you can expect 100-105 mph behind an 80-43 IF you run it at around 2600. The logic behind this is that with such a flat pitch,you're not pulling very much manifold pressure--ie,the engine is not working very hard. I'll buy that theory,except that it seems like wear would be increased on the engine parts.
Bruce,what powwer setting(s) do you use to see 100?

Eric

[auxtank]

My '48 ragwing does 85 KIAS (at 2350-2400 rpm) with an 80/43. That's 97.9 mph.

Gordon Sandy

[GAHorn]

I'm no injuneer,..but I believe you can have a small diameter prop with high pitch equal the efforts of a large diameter prop with low pitch because the thrust is equal to the mass of air moved by each. There's rarely an exact relationship that can be documented in fluid dynamics with such variables as different engines, different airplanes, different days, etc. with accuracy. It sounds as if an 8043 prop is doing about the same job as a 7651, from all I've heard, except that the larger diameter might give a bit of advantage "out of the hole" so to speak. I'd like to know (with an accurate tach reading) the static rpm of the 8043. Anyone?

[ak2711c]

I have a Borer prop on my 170B with a 145, and on wheels and light I get 98-100 mph. If I am heavy it is closer to 95 mph. I have not experimented with different props on a 170 to know if a 76-51 would give similar performance. However I have on Supercubs and I can tell you there is nothing that will come even close to the short field and climb performance of a Borer prop on a Cub. How much airspeed and rate of climb are you guys loosing of floats?
Shawn

[flyguy]

"gahorn" I'm no injuneer,..but... I believe... There's rarely... It sounds as if... I've heard, .." so to speak.

YEP THAT SOUNS LAK INJUN(EER) TALK! SUMORE TALK LAK THAT N YOU WILL GRADIATE FRUM FLAPPERJAW INJUN(EER) SKOOL. THEN WEEL TAKE YOU TO THU WOODS AN SEE IF URE GUD ENUFF TO BEE A REEL INJUN.

[zero.one.victor]

George,I'd put off graduation from Flapperjaw U. as long as possible. I've heard about what happens when yoy go out in the woods with them Leesiana boys!

[mit]

Ok, I went flying today here is what I came up with at 2,500 ft 20.5 " of MAP, 2508 RPM 81 MPH airspeed GS of 51 off the gps, on the way back at 2,500 ft 20" MAP 2460 RPM I was showing 75 MPH airspeed & 77 knts grnd speed It was tuurbulent on the way back so the # are not as good.
I have never seen 100MPH airspeed unless it was in a descent. This is with a 80/40 prop on floats. I have been passed by Cubs at the same power settings as i was using.

[zero.one.victor]

Bruno,we used to have a member who signed his posts "Liard Trapper".I don't remember if he had floats on his 170 or not. You still aboard,Trapper? Maybe you have some insights for Bruno?
I used to watch a fictional TV series set in your part of NWT called "North of 60".I think it was actually filmed in Alberta. Like most TV,it was probably not very realistic but I remember they had an airstrip right in the little town that was pretty much the only way in & out. Really enjoyed the show.

Eric