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Posted: Fri Feb 22, 2008 1:56 am
by pdb
hilltop170 wrote:
My airplane knows when it wants to take off, the less input it gets from me, the shorter it takes off. With the elevators in trail and trim set to just pick the tailwheel off the ground (1/16" would be perfect), will give the shortest roll. That is true whether I choose to use flaps or not. Load and DA determines if flaps will help reduce ground roll.
I agree with George and Richard but I might add one other point. An aircraft propeller is least efficient at low airspeeds. When I really have to make a short field take off, the last thing I am going to do is to taxi out, stop, runup and then release the brakes. That's more suited to a demonstration of technique rather than a real short field departure. (Its tougher on the prop too if you are a gravel or dirts strip.)
When I enter the runway or turn around at the end, I try to do so with as much speed as is safe and practical so that I spend the least amount of time in the least efficent regime of my engine/prop combination for acceleration. Keep it rolling...
Posted: Fri Feb 22, 2008 8:58 am
by jrenwick
The only time I ever thought I was in serious trouble in a 170 was when I made a right turn onto the runway with a left crosswind, powering up the engine as I did so. The left wing started to lift before I was lined up with the runway, and I thought I was going to groundloop for sure. I'm sure I didn't have left aileron in while I made the turn, and maybe I'd have been fine if I'd done that. But since then, I always make sure I'm lined up on the centerline with controls set correctly for the wind before I open the throttle for takeoff. That's what I would teach anyone transitioning to a 170, and to taildraggers in general. The rolling takeoff turn is strictly for highly skilled tailwheel pilots, IMHO!
Best Regards,
John
Posted: Fri Feb 22, 2008 12:03 pm
by N171TD
Thought this was about the best method for short field take off. The best all around way to get off short is have motion in effect when getting onto the strip. stated by pdb 1. Then get the tail up to reduce drag ( the least drag the faster the acceleration ) ( cruise is the least drag and that is a flat attitude ) 2. When you have the needed speed ( you know from experience and many hours in your plane ) FULL FLAPS and your in ground effect. 3. milk off the flaps as you gain flying speed ( this means using the mechanical flap handle and gently easing to 10 or 20 degrees for climb out ) On another forum a writer CD talks about more flaps on several take offs, good fun reading and very educational about flying in tough conditions.
Posted: Fri Feb 22, 2008 3:15 pm
by AR Dave
Obviously there is a hugh paradigm difference in what STOL is to different members of this forum. Like with so many other subjects that's been debated here, it's just almost impossible for someone that fly's on saturdays, off of 2500 foot runways, to relate to someone that work's off of 800' ruts, in the bush. I urge posters not to denounce someone's methods as theoretically incorrect, but only to share what you know about! From my perspective, if your 170 isn't on at least 8.00 tires, have an 80" climbing prop, and 180 gear legs, well let's just say I'm not thinking of you as an authority on STOL. When this subject was posted 5 years ago, there were experienced STOL pilots posting. I miss them!
Posted: Fri Feb 22, 2008 5:40 pm
by Green Bean
Amen
Posted: Fri Feb 22, 2008 5:53 pm
by N171TD
Well Mr AR Dave maybe 37 yrs flying starting in Ak in 71 with a SC and having owned many A/C including 170's might give me just a little more knowledge than you.
Posted: Fri Feb 22, 2008 11:00 pm
by flat country pilot
if your 170 isn't on at least 8.00 tires, have an 80" climbing prop, and 180 gear legs, well let's just say I'm not thinking of you as an authority on STOL.
I'm working on the tires but I don't consider myself an authority. I'm here to learn from you guys.
When this subject was posted 5 years ago, there were experienced STOL pilots posting. I miss them!
I do too. I think those old discussions got me interested in the 170.
Bill
Posted: Fri Feb 22, 2008 11:15 pm
by johneeb
American Heritage Dictionary - Cite This Source - Share This
par·a·digm (pār'ə-dīm', -dĭm') Pronunciation Key
n.
One that serves as a pattern or model.
A set or list of all the inflectional forms of a word or of one of its grammatical categories: the paradigm of an irregular verb.
A set of assumptions, concepts, values, and practices that constitutes a way of viewing reality for the community that shares them, especially in an intellectual discipline.
Posted: Sun Feb 24, 2008 1:58 pm
by AR Dave
Experienced STOL or Bush Pilots get that way when STOL flying is their work. They are pushed or challenged day in and day out to make calculated risk with weather, creek bed length, or how many antlers they can haul out.
Posted: Sun Feb 24, 2008 3:17 pm
by GAHorn
N171TD wrote:... ( cruise is the least drag and that is a flat attitude ) 2....
Not true. It's actually very high drag, since drag increases as the square of velocity. But we know what you meant.
Posted: Sun Feb 24, 2008 3:17 pm
by GAHorn
N171TD wrote:... ( cruise is the least drag and that is a flat attitude ) 2....
Not true. It's actually very high drag, since drag increases as the square of velocity. But we know what you meant.
AR Dave wrote:Obviously there is a hugh paradigm difference in what STOL is to different members of this forum. ...
Ol' Gar's "Kajun Hereatige Dikshunary" doesn't know hooo Hugh Paradigm is... but it ain't know Kajun name!

Posted: Sun Feb 24, 2008 4:58 pm
by N171TD
There are two types of drag parasite and induced. In taking off parasite drag is a detriment and induced drag is wing lift. Maybe reading the Pilots Handbook of Aeronautical Knowledge would be a good bet for a biannual sign off.

Posted: Tue Feb 26, 2008 11:28 am
by futr_alaskaflyer
Rules of thumb of aviation:
Avionics upgrades will only retain (at best) 50% of their value upon resale.
To estimate density altitude (at least at lower altitudes), start with pressure altitude and add 120 ft for every degree Celsius.
High wings are better than low wings, except when they aren't.
Any conversation about takeoff techniques will eventually cause the pant flies to become unzipped
The Cessna test pilots say to put in two notches (except at high DA), maintain a tail-low attitude and let her fly herself off when she's ready. In
this thread Richard P (perhaps stinging after the conversation above

) ground truths that direction and finds that - shocking - it still provides the best takeoff performance. Works for me too though I've never measured with a tape measure - yet. I can't speak to Super Cubs, Cessna 180s or King Airs. I'm no engineer but I can't imagine any circumstance where
full flaps would assist in a takeoff, at least on the B model.
Posted: Wed Feb 27, 2008 3:11 am
by markeg1964
I’m the owner of a small CPA firm working 10+ hour days seven days a week until April 15th. Needless so say I don’t do much flying this time of year. However, last night I decided to take off early (6:00pm) and stop by the airport on my way home to test what I’ve read on the forum. I’m a relatively new pilot with only 140 hours all in a 170A.
I only made four takeoffs and landings before it was time to get home to my lovely wife. In that limited amount of time I would say my shortest takeoff was made letting the tale fly itself just off the ground and then holding it low until the 170 was ready to fly. (I didn’t have time to see if one or two notches of flaps was best but I would guess two as that is what the book recommends.) I was surprised that this method worked noticeably better than holding the tail off. Of course I’m a beginner, I was a little tired, and it was dark.

Re: Shortfield Takeoff Technique
Posted: Thu Feb 28, 2008 9:35 pm
by Jr.CubBuilder
Good stuff, I appreciate all the input, I wish I could work on my own short take off technique but unfortunately the plane is going in for annual
I have also found the best success so far leaving the tail low and letting the plane fly off. I'm dubious about the flaps though. Using 20 degrees seems to get the plane in ground effect sooner (which would be good for soft field) but it seems like I could clear an obstacle faster with 10 degrees. When I get flying again I think I'll work on a combination of the two, start with 20 and milk it down to 10 once I've left the ground.