Takeoffs

[GAHorn]

Varr, It's my experience that the book figures are accurate. The problem is the perception one gets when actually in the cockpit with your loved ones aboard and the trees loom in the windshield. No spark-plug failure or dragging brake, or....????.... and you will make the book performance. But there's no reserve and the book is the BEST you'll get.
Even my cruise prop (7655) will get off the ground with about the same as book ground runs....but that climb to clear the 25' pwr line at the end of my strip can keep my attention on a warm summer day with full fuel and pax and baggage. It takes the full 3500' I've got sometimes.
(Remember - - Don't retract flaps until the obstacles are cleared! The book performance is done with the flaps at the takeoff position specified until obstacles are cleared. Flap retraction prior to the obstacle will increase distance required.)

Meanwhile.... back to the engine: The C145/O300 makes rated power (145 hp) only at 2700 rpm. No one gets that rpm though. (See the Type Certificate Data Sheet (TCDS) which specifies a standard prop will only make 2230-2330 static....This means you only get 120 hp at takeoff with a standard prop.)
If you can use a prop with a finer/flatter pitch you will get higher rpm and therefore more horsepower. That's why a "climb" prop will takeoff/climb in a shorter distance.
The "175 hp O-300" engine you've been told about is probably the GO-300 engine that was used in the C-175 airplane. It was not a success for several reasons. It only made 175 hp by using a gear-box which was built into the front of the engine between the crankshaft and the propeller. This allowed the engine to turn more rpms and therefore make more hp. It was like running the engine in second-gear all the time. This made the engine burn more fuel and wear out faster. (It only had a 1200 hour TBO and virtually none of them made it anywhere near that without major cylinder repairs.) The engine is now considered un-supportable. Many parts are no longer readily available, especially thrust bearings.
Even so, you wouldn't want to convert to that engine. It'd be much simpler to convert to an already existing, certified (STC'd) engine/prop like the Lycoming O-360 or TCM IO-360. (About $35K-$45K)

[N3243A]

do you have to get an stc for the 80" prop and what brand of prop?
varr

Yes, the STC for the 80" MaCauley 1A175 DM 80-42 (or 43) prop is available from Kenmore Air. With this prop I can operate in and out of 600 feet at less than 500' MSL on a 60 degree day at about 2000 gross weight under ideal runway conditions. You will use every bit of the 600' so there had better not be any obstacles at the end as in taking off over water or open ground. One of my tests to see if I was too heavy to go fishing at a remote gravel bar was to see if I could get up in the 600' of pavement at Birchwood's Runway 19L. There is exactly 600 feet from the threshold of 19L to where the remainder of the runway's gravel starts and If I could make it up before touching the gravel (always just barely) I knew I could get out of the mud bar I was going to go fishing at. This is with one adult pax, 1/2 gas and fishing gear only. Add soft sand or wet mud or grass to the runway and add more length too (sometimes a LOT more).

Having said that 800-1000 feet feels much better or put 10 knots of head wind on the nose. Just 10 knots of wind on take off helps immensely. Keeping that last 200 lbs out of the plane is really is important too (as in no adult back seat pax). Better yet pull out the back seat entirely and save another 25 lbs. Keep that back light and keep what weight there is forward so that tail can come up quicker.

Bruce in AK

[Alaska Flyer]

With two adults, one child, two dogs and some groceries it takes every bit of 1,000' to get off the ground. I need 1,600' - 1,800' to clear that famous 50' obstacle. That is with a C170B with a 160 hp LYC.

400' is possible (only tried on 800' strips) with two adults and fishing gear, 600' - 800' feels much better though and I agree, wind is your friend.

All of this said I agree with the other comments, make sure you have sufficient safety margin build in.

[flyer170]

I flew out of my neighbors strip for several years and it was 1500 ft long, grass, cut regularly, farm crops all the way around, no obstacles except when the corn was 9 ft tall. I have a 1950 A with the C145, the prop is a climb prop and I don't know the numbers off hand, just that it is not a cruise prop, guess I'll have to look it up . Anyway I could operate out of that strip comfortably with 2 adults full fuel and with the back seat out and about 40 lbs of baggage. The strip was at 930 msl On warm days with the tall corn I was glad I had the 1500 ft. With cool temps and short crops 1000 would have been alright. Having said that, I had to be able to set it down on the end where I wanted it, not a good idea to be floating down the runway. I never flew out of there with four adults on board.
Another challenge for me was the width of the runway 50 ft. When the corn was tall. 36 ft wing span, 7 ft on a side. I had to be carefull with cross winds.
Bob

[pojawis]

Another challenge for me was the width of the runway 50 ft.

Until very recently when the runway was rebuilt, my home strip was published as 40 ft wide. I actually measured it in several places and came up with a high average of just under 30 ft. Yes, the wingtips [of the 170] hung over the edges of the runway. The runway had to 'bulbs' at either end for turnarounds. Was easy to find as it looked like a very thin, double-ended thermometer. Good training to be able to find and hold the centerline with little problem...

[mrpibb]

Board at work
I agree with George on the book figures, two summers ago I flew a buddy and his "EX" girlfriend from jersey back to NH with a slight detour down the hudson river corridor for a quick sightsee. Andovers length is 1981 ft with clear departures to the north, and to the south your 50 ft obst is about 4000 ft. My weight was just shy of gross= three adults and 20 gal of fuel and min bagage. Oat was 76deg field elev. 586 DAlt was about 1500 that morn. My takeoff to the south was as follows, full power, full flaps (1948) lifted the tail to the tail low attitude per the poh. and waited for that leap skyward bound at the usual 900 to 1100 ft. however when i eased of the foward pressure holding the tail up slightly the tail just sat itself happilly back on the ground, well a little farther down about 3/4 of the runway things came alive and we became airborne shortly thereafter at about 55 mph (again as in the poh). cleared the 50 ft obstacle by 75ft then proceeded on our merry way cruise climb 250 fpm at 90 mph. Going back looking at the poh the figures were almost dead nuts on, current condtions called for a 1650ft ground roll and a 50ft clearance of 2850 ft.
We all like to think that our airplane has that something special that the other dosn't have, but in reality it is a machine born of engineering and science, and in my case in 1948 a rose was just a rose just as it is today.

[flyer170]

I just figured my take off distance to clear a 50 ft obstacle using the chart and at 75 degs at 1000ft msl about 2050ft at gross. Ground roll is about 820ft on hard surface.
That matches my experience on the 1500 ft grass if I add on a factor for the short grass and not hard surface. I also never flew out of there at over 1800 lbs. I did not have any 50ft obstacles in the area close enough to figure in. I guess I would not be comfortable with the 1000ft I spoke about
Bob

[flyer170]

I just found my prop #s it is a 7651 I think it is a climb prop but I don't know where it fits in on a scale of props.
Bob

[hilltop170]

There are some of us who are totally pleased with the 170's performance just like it is. We don't want it to be a high porsepower/high fuel burn/high performance airplane. If you want one of those, get one of those, there are lots of choices. We don't push the book numbers and are happy with that. As designed, it has a great balance of power, speed, efficiency, and it's obviously kool.

What I am hoping is the AOPA will have its way with the FAA and get 4-place, 180hp and less planes approved for flight by pilots with a driver's license and no medical. We should all support them on that since last I heard we're all getting older every day. Not to mention what that ruling would do to values of 170s.

I expect the 170 to be my final airplane, one I can handle by myself as I advance in age, and still be able to legally fly it for another 30 years or so. I'm 55 now and I'm going to enjoy the 170 the whole way.

It's fine to modify your plane any way you want it, but for me, I'm happy with its performance just like it is.

[Watkinsnv]

This idea that you don't need a medical is fooling a lot of people right now in the LSA market. And after its better clarified the LSA market might just flounder. Its true you don't need a medical. But you have to be healthy enough to pass one. If there is anything wrong with you, that you couldn’t pass a medical and you know about it you can’t fly LSA. Lose your medical buy a LSA Wrong. Don’t renew your medical because you know you can’t pass one, Buy a LSA Wrong. The FAA is in the process of making this a lot clearer. At my IA seminar I ask them all right questions that others said they wouldn’t or didn’t want to know the answers to. This is going to be a lawyers field day. He was in poor health and slammed his LSA into….. Killing…. And he knew he had.... Lance

[Robert Eilers]

I am happy with the 170 also. However, the one thing I might consider doing is having my prop modified to the California Prop. Does anyone have actual experience behind the California prop modifiction?

[hilltop170]

Lance- You are correct about flying without a medical. I currently hold a first class and by the time I can't pass one anymore, I hope I've had enough flying. We don't make the rules but we can play the game to full advantage. Having the medical exemption for 4 place, 180hp and below would be good for aging pilots. Knowing when to fly or not is still the pilot's responsibility no matter what medical they hold. Federal Aviation Regulation 61.53 requires that pilots voluntarily self-ground any time they have a medical condition that would adversely affect their abilities to safely act as pilot in command.

[bsdunek]

I just found my prop #s it is a 7651 I think it is a climb prop but I don't know where it fits in on a scale of props.
Bob

Originally, on the 170A, the 7651 was the 'climb' prop. The 'cruse' prop was 7653, and the 'seaplane' prop was 7649.

I have the 7651 on my 170A and like it. Dad bought the plane with it as we had a 1800 ft farm strip. It probably don't cruse as fast as the 7653, but I'm not in that much of a hurry anyway. I like the take-off and climb performance.

[bsdunek]

This idea that you don't need a medical is fooling a lot of people right now in the LSA market. And after its better clarified the LSA market might just flounder. Its true you don't need a medical. But you have to be healthy enough to pass one. If there is anything wrong with you, that you couldn’t pass a medical and you know about it you can’t fly LSA. Lose your medical buy a LSA Wrong. Don’t renew your medical because you know you can’t pass one, Buy a LSA Wrong. The FAA is in the process of making this a lot clearer. At my IA seminar I ask them all right questions that others said they wouldn’t or didn’t want to know the answers to. This is going to be a lawyers field day. He was in poor health and slammed his LSA into….. Killing…. And he knew he had.... Lance

Right on! I think all the effort of getting the FAA to have the LSA and RA ratings was a big waste of time. The ratings, IMHO, are mostly useless. While I'm a big supporter (and member) of both AOPA and EAA, I would rather they spent their effort on reducing the medical required for a Private.

[dacker]

I just had my medical yesterday (I'm 45), the inevitable finally happened... they had to print the little sentence "Holder must wear corrective lenses.". After having perfect vision up to about 42 or so, I woke up one day and couldn't read the newspaper, or the Kollsman window on the altimeter, or the fine print on the chart when I was flying to Recklaw, etc. I also have a weak distance correction, it is hard getting used to. For color of hair I didn't know whether to still put brown like in the past or "kinda grey"!
I guess that is what I get for having two pretty girls.
David