When to put the gear up...

minitour said:
But how much drag is created by retracting the gear (doors, retract cycle/motion) over just what is created with the gear dangling down.

IIRC (and it's been a while), in the 172RG the short field t/o procedure was to leave the wheels down until the obstacles were cleared because of additional drag created by the gear-up cycle.

-mini
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Codyjp said:
The cutlass manual never mentions a reason why the gear should be left down for the short field takeoff. It simply states that they should be retracted when the obstacle is cleared.
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In the C210 I always wait until no more usable runway. Takes for ever in a place like Memphis but it's so worth it, usually already at 600+ AGL by then.

According to our CP the reason for no retracting a Cessna gear during a short-field takeoff is due to the funky way the gear retracts. Apparently there have been accidents because people retracted the gear and then caught the obstacle they were trying to avoid.

dasleben said:
I would recommend coming up with as many callouts as possible. Everyone knows callouts makes your flying safer, and frankly, makes you sound cool:

"Power set" (Echoed by you for effect)
"Good engine"
"Airspeed alive"
"60 knots"
"Rotate"
"Positive rate"
"NEGATIVE runway remaining"
"Gear up" (Make sure that as you're saying this, you smoothly and smartly make the gear up motion with your hand)
"Gear up and in the wells, lights out"
"Climb power set"

Master these, and you're on your way to becoming a true professional pilot.
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Slight variations. My company does it "GEAR IN TRANSIT". And after flying that way for a few years I agree. The gear is not UP when you place the gear selector in the UP position. Especially in the Cessna gear it takes at least 7-8 seconds for the gear to fully retract. I used to say "GEAR UP" as well but I think "GEAR IN TRANSIT" is much more accurate and gets your mind wrapped around the thought that it's not up as soon as you place the gear selector up.
 
Both. Positive rate AND no runway remaining.

The hard part is teaching the student to be able to judge when you no longer have runway remaining.

One thing that became really popular around here was teaching that 1% of runway distance, plus field elevation = altitude to retract the gear. I've never been a fan of it, because it doesn't account for density altitude variations of performance, or wind. Every time I do a stage check and I hear that 1%, I have a short speech prepared :)
 
In light twins, I teach "positive rate, gear up" at an AGL altitude 20% of the runway length. Ie; 7000' of runway, gear comes up at 140' AGL.

Let's say it takes 1500' of takeoff roll, and initial climb of 88kts at ~1200fpm with the gear down, you're at 140' in ~7 seconds. 7 seconds at 88kts is another ~1040' down the runway. Now, at 140' AGL with the gear down and a decision is made to abort, you've got ~4460' of runway remaining. A 500fpm descent (conservative) to land from 140' should take ~17seconds, in that 17 seconds you will cover another ~2500' to descend, and another 1200' to stop. You should come to a stop in a total distance of 6240'.
 
7700 said:
In light twins, I teach "positive rate, gear up" at an AGL altitude 20% of the runway length. Ie; 7000' of runway, gear comes up at 140' AGL.

Let's say it takes 1500' of takeoff roll, and initial climb of 88kts at ~1200fpm with the gear down, you're at 140' in ~7 seconds. 7 seconds at 88kts is another ~1040' down the runway. Now, at 140' AGL with the gear down and a decision is made to abort, you've got ~4460' of runway remaining. A 500fpm descent (conservative) to land from 140' should take ~17seconds, in that 17 seconds you will cover another ~2500' to descend, and another 1200' to stop. You should come to a stop in a total distance of 6240'.
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I meant 2% for the above, but what blizzue says, that can vary based on the conditions...
 
bLizZuE said:
One thing that became really popular around here was teaching that 1% of runway distance, plus field elevation = altitude to retract the gear.
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At my home 'drome that means *doing some quick math* 1300' to retract the gear.

Is that MSL or AGL? AGL would mean tooling around with all of that drag for quite a while. MSL would mean you're pretty much "positiverategearup" in all but the lowest powered singles.

-mini
 
7700 said:
I meant 2% for the above, but what blizzue says, that can vary based on the conditions...
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I can't be the only one thinking this...where the heck did you get this from? I am not saying it is bad, just. . .interesting.
 
bLizZuE said:
One thing that became really popular around here was teaching that 1% of runway distance,
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Hey, that's pretty good - I like it for the usual C-172/82RG type airplane on a usual GA runway - 3 to 5000 feet. That comes to 30 to 50 feet which is in the neighborhood of when you don't have enough runway left to land on. Of course, that means you are practiced at actually doing it, and making the altitude/distance judgment.
 
We raise our gears on the Barons and Bonanzas after positive rate. It has never concerned me because our gear motor cycles the gear down very quickly if it was ever required to lower again due to engine failure and also the last time I checked a belly landing on a runway was very survivable (if it came to that). At a prior school we waited until positive rate and runway unusable but it was not a policy. What cracks me up is the people who translate runway unusable to mean waiting until crossing over the departure end of the runway. LOL
 
As MikeD said, there is no one answer. IMO, you are almost always better off getting the gear retracted at positive rate in the GA singles, unless the AOM/POH dictates otherwise.
 
minitour said:
Seems like kind of a waste on a 9003' runway to be sucking the gear up at 90' in a piston single. Even 180' in a piston single. Climbing at Vx or Vy, that doesn't put you very far down the runway.

-mini
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I never said I liked it, nor do I teach it. Someone somewhere started using it as a guideline perhaps, and now it seems to be a hard and fast rule taught to primary students.

For me, the gear doesn't come up until I am no longer capable of landing the aircraft on the runway remaining. That comes from just looking outside.
 
minitour said:
Seems like kind of a waste on a 9003' runway to be sucking the gear up at 90' in a piston single. Even 180' in a piston single. Climbing at Vx or Vy, that doesn't put you very far down the runway.

-mini
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mini, you may not be that far down the runway but getting the bird back down and stopped is what eats up a ton of real estate and most likely will put you off the end. Also, remember, the prop gets feathered or it siezes then you will have even more float from the reduced drag.
 
bLizZuE said:
I never said I liked it, nor do I teach it. Someone somewhere started using it as a guideline perhaps, and now it seems to be a hard and fast rule taught to primary students.
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I wasn't tryin to say anything about liking it or teaching it man. :beer: And as was previously posted, on a 3-5k foot runway, it actually probably works out because...

Bandit_Driver said:
you may not be that far down the runway but getting the bird back down and stopped is what eats up a ton of real estate and most likely will put you off the end.
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...which is a great point.

-mini
 
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