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Thread: Grass strip takeoff

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    Default Grass strip takeoff

    What takeoff distance is needed for a 180 Super cub, Super 170, 180 on firm packed grass strips? Thanks

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    Default Takeoff distance

    [QUOTE=outdoorRN;1667034]What takeoff distance is needed for a 180 Super cub, Super 170, 180 on firm packed grass strips? Thanks[/QUOTE

    Look in your POHs . . .

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    OUTDOOR RN:

    It depends on a LOT of variables.

    A. How much of a load is in the plane?
    B. How high is the take-off elevation?
    C. How Hot is the air and what is the baro pressure?
    D. Is the take-off surface level or slanted?
    E. Is there any wind?
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    Grizzly 2 is spot on. You have to also consider other factors, tire size/pressure, prop, engine condition, Temp, slope, load, pilot skill, and wind just to name a few. All of the above factors can double or triple the listed distance needed to get in the air. Do not look at U tube videos of planes landing and taking off on the knik river with a 30 mph headwind and think that is what the plane will do. Same for Valdez and other STOL comps. On a cool day with 10 mph on the nose I can get a empty cub with little fuel up in 100 ft. On a hot day with no wind and a full load it may take 800 ft.
    DENNY

    Looks like float pilot beat me to it.

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    Many Moons ago,( maybe 1995) my daughter and I went to a take-off competition / clinic at Wasilla with my old PA-12. I was all happy with myself by making 400 ft take-offs on gravel with a fairly full load on a warm day.

    LATER THAT AFTERNOON: I took a 200 pound mine owner out to his claim north-east of Chickaloon. It was high and hot back in the canyons and it took me 800 feet to stop in the weeds. Later that night, after clearing away rocks and big sticks, I took off through the smashed down weeds and it took me at least 1,200 feet to get airborne before we drifted out over a flooded creek. It might have been further. It was like flying a wheel-barrow full of dirt.
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    Quote Originally Posted by Float Pilot View Post
    Many Moons ago,( maybe 1995) my daughter and I went to a take-off competition / clinic at Wasilla with my old PA-12. I was all happy with myself by making 400 ft take-offs on gravel with a fairly full load on a warm day.

    LATER THAT AFTERNOON: I took a 200 pound mine owner out to his claim north-east of Chickaloon. It was high and hot back in the canyons and it took me 800 feet to stop in the weeds. Later that night, after clearing away rocks and big sticks, I took off through the smashed down weeds and it took me at least 1,200 feet to get airborne before we drifted out over a flooded creek. It might have been further. It was like flying a wheel-barrow full of dirt.

    ^^^^ This x 3....certainly for a -12 anyway. My cabin strip is grass / dirt and has 1000' of good surface plus another 200 that is useable to stay in ground effect, but wouldn't want to roll on it too much.

    If conditions are right (light..a relative term with my butt in the seat, cool, breeze blowing up the downhill slope), I'll regularly have liftoff in less than 300'. If conditions are not right (hot, heavy, breeze blowing the wrong way, dead air,etc), I'll regularly have liftoff at somewhere between 500 - 700'...and I'm glad to at least see another few hundred feet of runway.

    My goal is to eventually get to the point where the pilot's abilities don't limit the plane. Long way to go for that.......

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    Quote Originally Posted by boneguy View Post
    Grizzly 2 is spot on. You have to also consider other factors, tire size/pressure, prop, engine condition, Temp, slope, load, pilot skill, and wind just to name a few. All of the above factors can double or triple the listed distance needed to get in the air. Do not look at U tube videos of planes landing and taking off on the knik river with a 30 mph headwind and think that is what the plane will do. Same for Valdez and other STOL comps. On a cool day with 10 mph on the nose I can get a empty cub with little fuel up in 100 ft. On a hot day with no wind and a full load it may take 800 ft.
    DENNY

    Looks like float pilot beat me to it.
    The STOL comps are really dumb. No one ever flies like that. 40 mins of gas and every ounce of anything taken off the plane plus don't forget to take a crap so you're .5lb lighter.

    They demonstrate nothing at all.

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    OUTDOOR RN:


    As Griz said the POH's used to have that data for grass strips. Or at least the had a note saying to add so many percentages of the take-off distance listed for a softer surface. SO I dug out a few old POHs that are here on my junk littered desk.

    1961 Cessna 150 A.......................Could not find any notes about grass field
    1961 Cessna 175B Skylark........... Could find no mention Kinda weird...
    1961 Cessna 172B Skyhawk.........Could not find it in there either..
    1968 Cessna 177 Cardinal............TAKE-OFF add 7% of total distance for dry short grass. LANDING, add 20% of total distance.
    1974 Cessna 150........................TAKE-OFF add 7% of total distance for dry short grass. LANDING, add 20% of total distance.
    1976 Cessna 172M Skyhawk........TAKE-OFF add 15% of total distance for dry short grass. LANDING, add 45% of total distance.
    1976 Cessna 180 Skywagon.........TAKE-OFF add 15% of total distance for dry short grass. LANDING, add 40% of total distance.

    1965 Piper Cherokee 140.............Just says to use flaps in the grass. nothing else.
    1969 Piper PA-18 Super Cub.........No mention of grass
    1947 Piper PA-12 Super Cruiser.....Only mentions wet pavement....
    1946 Piper J3C-65 Piper Cub.........No mention of any distances
    1973 Piper PA-28R ARROW............No mention of grass, just says to use flaps on soft fields.

    Gotta go...
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    Quote Originally Posted by z987k View Post
    The STOL comps are really dumb. No one ever flies like that. 40 mins of gas and every ounce of anything taken off the plane plus don't forget to take a crap so you're .5lb lighter.

    They demonstrate nothing at all.
    I do not think the STOL comps are bad at all. It is actually a great learning platform for pilots if done correctly. In Alaska most all the pilots will share tips on how to land and takeoff, and how not to get hurt. If you think your last heavy landing on a remote strip was hard, now just think if it was live streamed to 15,000 people over the world and forever on U-tube if you screw up, that is the stress of Valdez. In a STOL contest if you land short or long the only thing hurt is pride, learn from it and you will be a good pilot. Just don't watch and think that any plane or mod does it on a daily/heavy basis. I usually fly with full fuel, extra in the back and at max weight, but I do know pilots that do take EVERYTHING out of the plane and have 5 gal left to get in and out of sheep camp, or go play on the Knik. The bottom line is every plane/pilot/day is different. Start with the POH and build off that.
    DENNY

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    POH is a fine start, but no plane flies like it did when it left the factory, with that factory test pilot doing their thing in ideal conditions. Most POH’s specify dry grass, and their percentage additions are typically inadequate for what we find in reality.

    Only way to definitively answer your question is to fly YOUR plane at temps, DA and weights you’re anticipating off surfaces akin to what you’re anticipating, with lots of reserve distance for safety, and find out. Write it down. Do it again until you’re satisfied. And, be ready to shuttle folks, equip, fuel, etc when conditions don’t favor your takeoff (and sometimes landing).

    800’ strips at 5,000msl in ID are easily doable in my 180 when it’s cold out and plane is light, but no way am I doing it during the summer. Why not? Cuz I loaded up the plane to expected weight and tried it on a longer strip and wasn’t comfortable with the margins.

    Any “bush,” canyon or mountain flying is best done first with a locally knowledgeable instructor, then with a toe in the water on your own u til applicable experience is gained. You (and your unsuspecting passengers?) deserve that conservative approach.

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    We takeoff distance required on grass is derived from published takeoff performance data charts the

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    I’m with Grizzly 2 on referring to the POH if such data exist. Once your actually on the ground looking at the takeoff situation the old standby of having 70% of liftoff speed required at the 50% of the available distance is a good way to avoid the need to call those guys over at Pioneer Helicopters to do an aircraft recovery. If you do not have 70% of the needed speed at half way point, walk off and set a visual marker beforehand, close the throttle to stop the takeoff run. From the preflight planning point of view there may or may not be adequate published data available. From Float Pilots research into old POHs it looks like Cessna occasionally did supply percentage increase corrections. If my airplane didn’t have the correction factor data then my personal solution would be to begin with the highest similar % numbers correction. Just don’t be afraid to close the throttle and try something different while there’s still room to do so. The variables of grass surface rolling resistance are great.

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    What he said.

    Quote Originally Posted by upstreamV View Post
    The variables of grass surface rolling resistance are great.

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