To retract, or not to retract, that is the question..

[Guest browng]

Before I start, there is no absolute right or wrong here, it is an age old controversy that still rages, but here goes....

 

You are flying a single engine retractable gear type, you start your takeoff roll and have just rotated and are airborne, do you;

 

(a) Retract the gear immediately for minimum drag and best climb?

 

(b) Leave it down until all useable runway is behind you in case of engine failure?

 

© Now repeat the same scenario and questions in a twin engine type.

 

What would you do?

 

 

[motzartmerv]

In a single engine i would retract after the usable runway has passed underneath and then clean up..But in a twin i would retract as soon as a possative rate of climb is attained ..this is becasue the chances of 1 engine failing b4 the other would be much higher then both at once..in twins u need to be clean as possible when one engine fails (they tell me) as 85 % of performance is gone with one engine failed..flaps up gear up, prop to feather...if you dont do all these things the assymetry induced by the one engine will be impossible ot overcome with control deflections, and u stall/spin..a belly landing is better then a spin into the dirt..Ive said it b4 and ill say it again...The angle of arrival is directly proportional to the probability of survival...my 2 cents

 

 

[Guest browng]

in a twin i would retract as soon as a possative rate of climb is attained ..

 

 

You are talking about the need to obtain SSES (Safe Single Engine Speed) as soon as possible after liftoff. It varies with type, but between 15knots and 25knots is a reasonable estimate between liftoff and SSES. So for a twin it seems a simple decision, and I would agree, but for the single however it is not so simple......

 

 

 

Any more offers?

 

 

 

 

 

 

 

 

[Guest High Plains Drifter]

Read the flight manual for guidance ?

 

HPD

 

 

[facthunter]

Retract point.

 

For a SINGLE engined aircraft, depends on whether you have a near obstacle to clear, if so, retract the gear with a positive climb rate and the proper climb speed at about 15 feet. If it's a CESSNA, the drag with the gear part-retracted is more than with it DOWN so take that into consideration, if the initial climb angle is critical. If none, what's the hurry with getting the gear up? You still might need it. It's better to land wth the U/C down, except when ditching, where the gear should be retracted. Nev..

 

 

[Guest browng]

A few more points to ponder.

 

1. Some types can reach the max gear retraction speed quite quickly, particularly those with high power and U/C doors attached to the legs.

 

2. Some types have sequencing valves in the retract mechanism that prevent the cycle being reversed until the current cycle is complete, i.e. if you start a retract, you can't put them down again until the retract is complete.

 

3.Some types do not retract the legs synchronously, i.e when one is fully retracted the other is still on the way.

 

If you have a combination of 2 and 3 plus an engine out, you could end up landing with one up and one at least partially down.

 

Any advance on Facthunters analysis ?

 

 

[Flyer]

I was taught to leave the gear down while there is a chance of putting it back on the runway. Once the runway is behind you, get the gear away and put some altitude between you and the ground.

 

As for twins, I've no time and training in one so I'll sit back and learn something....

 

The 3 most useless things to a pilot....

 

1. Altitude above

 

2. Runway behind

 

3. Fuel in the bowser

 

regards

 

Phil

 

 

[Guest Andys@coffs]

Ok, I'll have a guess (and its just that as I dont want to play the retracts game, = more complexity = more fragility=greater cost=less choice of landing sites = why wouldya want to in the RAA context?)

 

Know the cycle time, if it takes 15 seconds to put it back out you better be sure that you have at least 15 seconds for that to occur and positive lock to happen before the mains will touch which ever ground youve decided will approximate a landing strip . If as others have suggested it takes 15 to put it away and then 15 to get it back out then that sort of limits you to being at around cct height I would have thought (1000fpm = 1 minute = some time to do the WTF!!! thing before transitioning to the "I suppose I better do something" phase.

 

Andy

 

 

[Guest ozzie]

The one exception to the phrase 'what goes up, must come down' is retractable undercarriage

 

 

[Guest J430]

Here is a thought, and from the very experienced too (not me directly), in saw a Bonanza the gear retracts quickly and during retraction not much increase in drag.

 

Now take a 172Rg or 182RG or 210 etc.........they are bloody awful angly legs during the cycle and very draggy during it. best to leave them out until well clear of obstacles and say 700' or so AGL and then retract. If terrain is good maybe lower.

 

J

 

 

[Guest browng]

The main counter argument goes like this, Yes, leaving the gear down until all usable runway is behind you, (including the overshoot area), is good idea, but if you have an engine failure at precisely that point, you are now lower than you would otherwise have been, and draggier, therefore your choices are now severely limited as to where to put it down.

 

As I said in my OP, there is no absolutely correct answer. Personally I agree with Facthunter's analysis, I too was taught that getting the gear up was not a race, as long as you did not exceed VLO (max gear retraction speed). Incidentally, if you do exceed it, you can still safely fly the aircraft with the gear down up to VLE (max flying speed with the gear extended), VLE is usually significantly higher than VLO

 

 

 

George

 

 

[Flyer]

You certainly don't want to have a race in a Cessna 172rg as when you tuck the gear away it swings lower than fully extended. (does that make sense?) I have seen the results of a partial gear extension landing in one of these. Not pretty and no I wasn't the pilot...

 

In a Piper Saratoga, getting the gear away is equivalent to getting rid of about 10deg of flap in drag, consequently I get it tucked away reasonably quickly to assist the performance.

 

Hot and high out of Alice Springs where I did all my training, you went for as much performance as possible...

 

regards

 

Phil

 

 

[Guest browng]

A question for any RAAus instructors here. As a pilot who did a PPL to AUF conversion, I have never undertaken the full AUF/RAAus syllabus, given that retract (and CSU) are permissible on RAAus types, what type training is given in their use? I do realize that there is currently no requirement for such training, but I am curious as to how people get checked-out on them.

 

 

[Guest J430]

browng

 

I started off doing the RAA trainingand then continued with PPL and then later CSU & Retract endorsements, and I did it so I could have both.

 

There was NO training on CSU or retract and when I did my training there were some very interesting things taught, that in an emergency could be a life saver.

 

Myself I do believe that it should be a requirement, its not hard, but it should be like a passenger or x-country endorsement.

 

I really think that RAA flying should be kept simple, no CTA, No CSU and retract......keep it simple affordable and safe. Ohhh and fitted with transponders!

 

J

 

 

[IanR]

Just looked at some checklists and manuals I have -

 

For twins it seems universal that the manual says "retract when positively airborne"

 

For singles most say "retract when airborne and insufficient runway available for landing"

 

That certainly matches what I was taught in both situations - particularly when obstacle clearance is not an issue.

 

 

[Guest pelorus32]

A question for any RAAus instructors here. As a pilot who did a PPL to AUF conversion, I have never undertaken the full AUF/RAAus syllabus, given that retract (and CSU) are permissible on RAAus types, what type training is given in their use? I do realize that there is currently no requirement for such training, but I am curious as to how people get checked-out on them.

The new ops manual which has been approved by CASA as I understand it and which will apparently come to you early next year contains, inter alia, CSU and retract endorsements.

 

M

 

 

[Yenn]

Why no CSU for RAAus. Several planes in the RAAus fleet have adjustable props and as I see it an adjustable prop is harder to handle than a CSU unit.

 

 

[Guest ozzie]

basically taught that when showing positive rate of climb 'gear up, then 500ft flap up' (nomad).

 

 

[facthunter]

Procedure for gear retract.

 

Ozzie, that is the correct procedure for multi engine, where the engine-out climb becomes the critical factor. It could be noted that gear extended ferry can be available ( at a reduced weight , to allow the climb to be achieved ). Nev...

 

 

[Guest ozzie]

i didn't do this, I just pick em up. the ferry to workshop was with gear locked down and reduced speed applied. the tailplane also had to be replaced lots of poped rivets and canning on it. good thing it rolls on its wheels when the door skins crush up.

 

result from a attempted go around in a storm. must have positive rate of climb before selecting gear up. there was about 1000mts rw left

 

personally i'd wait a bit as when the mains doors open they are a few square feet of drag.

 

anyone out there ever work on these?

 

ozzie

 

 

 

 

[Guest High Plains Drifter]

anyone out there ever work on these?

 

 

Yes I did, back when I was a male stripper (guess what I did)

 

HPD

 

 

[Guest ozzie]

ahhh grease the pole?

 

http://au.youtube.com/watch?v=EPE-3FKh2_4

 

 

[Guest High Plains Drifter]

yeh, it was a dumb joke ozzie - when I was a teenager travelling around Aus, I did a short stint as an aircraft paint stripper.

 

When I was stripping a Nomad, I wondered why it had retractable mains, it seemed to me that a fixed and faired gear wouldnt take much away speed wise - considering the aerodynamic mess of the gear pod, struts etc.

 

HPD

 

 

[Guest ozzie]

absolutely weirdest set of retract gear i've seen. narrow, oleos, small wheels, small brakes and heavy.

 

chain drives the nose gear. if you fill the tip tanks the oleo will drop and suddenly the wing tip is 3 feet lower or jammed on the ladder. come to think of it the only good thing about this aircraft was that it filled your schedule of experience log real fast.

 

Stripping paint, been there and never again. But i am a wizz with a gun.

 

 

[facthunter]

Weird retract.

 

So little achieved by retracting the gear (partially) .All the complexity and weight. I always thought that the faired wheel cover should have moved instead of the wheel. You would have achieved almost as good a result drag wise.. Nev...