The International Cessna 170 Association

Hi all!
I'm in the market for a 4 seat taildragger to haul my family (2 adults, 2 kids - 600lbs of people) for $100 pancakes for the next few years. The 170 is on my list of options. My question is about takeoff performance. I'd like to be able to operate it off my 1450' grass strip (@1200' MSL) - will it safely do it?

Thanks in advance for your input.

For me that is a little tight. If you can find a 180hp conversion in your budget it would be much more realistic.

Climb prop, half tanks, no obstacles would all make it more manageable, but I think it would be outside my comfort level.

I bought my 170 as a family hauler and in 6 years have had all four of us in it once or twice, and now they are both off to uni. My son only comes home to borrow the plane, and yes he leaves it just about out of gas when he brings it back.

That said I can't think of a friendlier plane with better manners and such reasonable operating costs.

With a stock 170 at gross weight on a summer day, I wouldn't try it unless there was nothing at the end of that 1,400' strip but field mice.

If you're not worried about speed, a sea plane prop would let you use that field quite easily. But your cruise will go from 120mph to 100mph.
Not much of a difference unless your burger of choice is on the other side of the state.

With a climb prop, you could use that field at gross on all but the hottest summer days but you might want to tell the field mice to duck once in a while.

I don't know of another all metal 4 place taildragger that will do better than a 170 tho.
EDIT: I forgot about the 180 - It will do better than a 170 but the price and operational costs are a little higher.

NovemberPapa wrote:Hi all!
I'm in the market for a 4 seat taildragger to haul my family (2 adults, 2 kids - 600lbs of people) for $100 pancakes for the next few years. The 170 is on my list of options. My question is about takeoff performance. I'd like to be able to operate it off my 1450' grass strip (@1200' MSL) - will it safely do it?

Thanks in advance for your input.

Well that depends. Are you at sea level? Is the runway down hill into prevailing winds? Do you have a clear departure path for a few miles?

Depending on your answers, you would be living near the edge even with a 180hp. Realistically even with the 180 I think you would be uncomfortable. At best there would be little room for error.

My 170A with C-145 and '51 climb prop was operated out of a 1350 one way grass strip at 350ft msl here in PA for years. The prevailing wind was not down the runway with the clear approach. They rarely left this field with 3 people unless they were small and never with more than half tanks. My buddy operated a 180hp 170B off the same strip. I was with him many times. He probably wouldn't take the time and think hard enough as to whether he could do it, preferring instead to arrange to pick up the extra people at the longer airport a few miles away. Flying should be fun. A mental exercise with your family at stake every departure is no fun.

I currently operate my 170A C-145 with a standard prop off an 1800 ft one way grass strip with left quartering prevailing head wind coming through large tree line just to add some turbulence. Often it is nearly a 90 degree crosswind through those trees. There is better than a 3% down hill slope for take off. We must clear a 60 ft house roof immediately at the end of the runway or fly between it and the tree line on the left. We must make a go no go takeoff decision int he first 300 ft just as we get light and go down the slope or we will not be able to stop at the property line and into the house yard we will go. We do not depart the airport with more than half tanks and usually one person. If its cool and winds are favorable, half tanks and 400 lb of people is doable but not for the faint of heart. You have to believe and can not second guess your departure. The 3000 ft paved runway public airport is 1.5 miles off the end of our runway. We actually depart into the base of the other airport and don't even raise the flaps from takeoff to landing there. We have no reason to push it and we don't try to do so yet sometimes things happen and a pucker factor starts our flight.

I have 180hp in a 170A and can get off the ground with full fuel and 4 pax ( 400 kg of lard) at sea level on a standard day at sea level . Using 10 deg of flap. I had to do that running from a bush fire . It was a lot less than 1300ft . Will look it up when I get home, Admittedly I was worried ( scared stiff) but pleasantly surprised .

Note. I have been out to measure the TOD and its around 650 ft . The surface is hard baked earth. I do not know how we did that day with slight head wind .

ghostflyer wrote:( 400 kg of lard)

That is 880 lbs those of us who use US Standard units.

I believe Cessna engineers and test pilots did a good job in documenting performance info on the 170 and have personally found the numbers to be accurate with normal piloting technique. Looking at the C-170A Owner's Handbook, it clearly states with a (stock) airplane and (stock) engine in good condition at Gross Weight, Sea Level, Standard Conditions, No Wind, ON A PAVED RUNWAY the takeoff distance over a 50' obstacle is 1820' with a ground roll of 728'. Similarly, the landing distance over a 50' obstacle is 1755' with a ground roll of 790', also on a PAVED RUNWAY. Grass runways will lengthen the takeoff who knows how much, depending on conditions. Performance degrades significantly with increased density altitude, ambient temperature, and worse runway conditions.

I live on a 1400' seal-coated hard packed gravel strip at 375'msl that is usually at about standard conditions or better with no obstacles. I have taken off with no wind, full fuel, and three 200 pounders with my O-300D/76-55 cruise prop. That would make it about 100lb over. We used a good 1000' for takeoff and would not have cleared a 50' obstacle at the end of the runway.

I would not hesitate to operate off a 1450' grass runway but loading would be adjusted for conditions and not be anywhere near gross weight. Loading up to gross can always be done at an appropriate airport somewhere else.

I've got a two phone videos, one of me taking off and one landing at my 650' strip ( approx. 500' usable), If somebody knows how to turn them into a postable link let me know...

Joe

Put them on YouTube and copy and paste the link.

Grass extends takeoff ground-roll by 20% if it's less than half-wheel-height and dry. (I don't recall where I got this bit of info, but it's been with me for about 40+ years and seems to work. I think it was from an old-geezer...perhaps he got it from old-geezer-school....maybe bluElder attended that school and can pitch-in..??)

Taller grass (than half wheel-height) really adds to the takeoff distance due to rolling-resistance.

Wet grass will make that worse and upon landing, will behave as if it's greased....(as it will if you abort that takeoff....which I HAVE experienced with shaking knees.)

hilltop170 wrote:Put them on YouTube and copy and paste the link.

Will do when I get around to it, I'll have to round up the people that took them.

Joe

I would be leary about operating out of 1400 ft of grass with 2 adults and 2 kids. I used to fly into a 900 ft ultralite strip with my 170B with a Horton STOL kit. By myself with no more than 1/2 tanks, it was OK. I did it once with another big guy in the right seat and it was another story. Better safe than sorry, buy a light 182 or 180.

I have a 54b with a o 300a on it, with a Horton stall kit, and 175 wings (10 extra gallons of fuel). I am based at 64fa in South Fl and routinely fly full tanks, me, my wife, 2 boys (3 1/2, and 21 months) with everything you can squeeze in the aircraft including the kitchen sink on hot summer days. I would have no problem flying off our 1,980 grass strip with 50 foot trees on the east end. Not sure I would do it off a 1,400 strip unless there are no obstacles to clear. My ground roll seems to be about 800 to 1000feet on a hot day (90f), and climb out about 300fpm at 100mph indicated. Just some rough numbers so take it for what it's worth. My rule of thumb is 2000 foot runway I am good to go, less than that I have to start asking questions and doing research. By myself or another large male and I, and no bags she is a different airplane. 500 foot ground roll and 500fpm or better all day long. Hope this helps. I am truly happy with the 170 as a family airplane and routinely fly from FL to NC to visit grandparents, and all over the Southeast. Would 20kts faster be nice. YES, but at what cost. Decent 180s were in the $80,000 + range 3 years ago when we bought ours. For the money and "cool factor" you can't beat a good 170.

gahorn wrote:Grass extends takeoff ground-roll by 20% if it's less than half-wheel-height and dry. (I don't recall where I got this bit of info, but it's been with me for about 40+ years and seems to work. I think it was from an old-geezer...perhaps he got it from old-geezer-school....maybe bluElder attended that school and can pitch-in..??)

Taller grass (than half wheel-height) really adds to the takeoff distance due to rolling-resistance.

Wet grass will make that worse and upon landing, will behave as if it's greased....(as it will if you abort that takeoff....which I HAVE experienced with shaking knees.)

Makes sense, but I'd like to understand it better. Is this due to the rough surface disrupting Ground Effect or because the airflow into the pitot tube is somehow disrupted, again due to the rough surface affecting static pressure? Without accurate airspeed indications, rotation speed ends up indicated later than normal thus extending the takeoff roll. Or is it really the difference in friction between the ground and gear? I'm trying to figure out where the difference between grass and pavement exists here: L = (1/2) d v2 s CL... (WARNING, NERD ALERT). I have experienced this phenomenon but I never really gave it much thought at the time. I was just thankful that we made it off the ground without hitting the trees and immediately filed the experience in the archives under the "Forget that crap!" tab.

I have a grass strip setting @ 3400' msl with 800' useable. On a 58 deg. day I used the majority of it (750' +) with myself & 115 lb grandson, (310#), full fuel, cruise prop, etc. That was the deciding factor in going to eng & prop upgrade. I am still working with the new equipment, but have cut the distance by 200', & I don't have it dialed in good yet. Very happy so far!

Does anybody have any specs with climb props on the O300? If you are not worried about cruise, could be the way to go, especially with 1450' of strip.