Heavies flying with their wheels down....... My question.

[facthunter]

I'm curious why trim is there and flaps? Trim is done anytime (except in turns) to relieve stick forces. Trim (rudder) IS done in a multi when the approach is done with a motor out to avoid the bias causing a yaw when the remaining engine(s) are throttled back near the flare. That's not RAAus stuff.  

  Flaps are planned as appropriate for your circumstances . Most lighties  it doesn't make a lot of difference in your circuit size  OR you threshold target speed.  and a goodly % don't have them  (even some GA).

  A flapless is an abnormal operation in a commercial jet.. You'd add over 60 knots to your approach speed. You'd probably scrape the tail and exceed the tyre speeds..  and need a lot of runway and a larger circuit size. Nev

[Flightrite]

PUF is/was common, I still use it today from basic stick & rudder to Transport Cat machines, silently of course in two crew😉

[Bosi72]

By the same analogy why Undercarriage if large % of RAA aircrafts have fixed gear? Why Pitch when % of aircrafts have fixed prop.. 

 

Checklists are here to help because we are humans and we make mistakes. BUMFOH, PUFT, TMPFISCH, CFMST, FMOST etc.. are not in any CAO, CASR...  it is up to a pilot in command whether he/she wants to use them.

 

Back to question..

Agree, an aircraft can land flapless and without trimming.

However, applying full flaps when turning downwind to base would make a trip to threshold very long. I usually apply last stage of flaps on final (if required).. 

Finally, imagine after base to final,  when you push Pitch to fine, then you realise that Undercarriage was not extended earlier on a downwind (thanks PUFT), then apply last stage of Flaps, that would cause a lot of imbalance. Certainly Trimming would help with controlling the aircraft.

 

So the checklist PUFT, and in that particular order, make sense to me regardless whether I fly RAA or GA.

 

 

 

 

[facthunter]

There's GOOD reason to have TRIM in the pre take off checks, as it could be anywhere. and THAT is dangerous. Once you are in flight you  trim to remove control forces automatically apart from the times I elaborated on above.. Nev

[flying dog]

If you are still reading this....

 

This is (I hope) the clip I mentioned way back.....

 

Enjoy.

 

 

[F10]

On 27/11/2021 at 1:06 PM, onetrack said:

Wouldn't a set of wheels left down and left to spin at takeoff speed, after takeoff, take a considerable length of time to slow to low RPM's? - and wouldn't that set of spinning wheels, which are usually unbalanced due to flat spots from landing, provide a level of gyroscopic imbalance to the aircraft? 

I was always taught, “brakes” (quick dab on the pedal tops), before gear up or down. When retracting, it stops spinning wheels, which I think is important. Imagine the damage a spinning wheel that had thrown a section of tread, could do to hydraulic lines, fuel lines, who knows what, in the wheel bays? Even a spinning good tyre, could be rubbing on something in the bay?When extending the gear, “brakes” shows your brakes have pressure in the lines and still should work.
Another angle to this, I often see early gear retractions, by GA aircraft…I think it is better to leave the gear down after taking off, up to the point where a land back is not possible, or the terrain ahead is more suitable to gear up landing.

As for overspending gear, the parts that will be damaged or break off, are the delicate and often light gear doors. I do not believe even an F14 could rip its main gear off, the drag would be too high to accelerate to that speed. Also, if the gear was extended at high speed, I still think it would not rip off, but serious airframe damage would result. Those gear legs are strong! 
One good story, as related in Larry Forresters “Fly for Your Life” the Story of Bob Stanford Tuck, now officially credited with 30 kills in the war, (still my best book on WW2 air combat, Reach for the Sky included), after a rushed scramble when leading 257 Sqn Hurricanes, Tuck found his Hurricane was yawing and pitching, not accelerating. Thinking something was wrong, he glanced around the cockpit, not even thinking the obvious, when Pete Blatchford pulled up next to him, mask removed showing a big grin and held his left hand up, with two wiggling fingers pointing downwards….Tuck immediately realised, he had for the first time ever, forgot to raise his gear! Furiously he ripped it up, whilst flashing a rude gesture!

[Jase T]

Long taxi at heavy weight can equal hot brakes.So can an aborted take off. Certain warnings on ECAM or similar can require a minimum break temperature before you can retract the gear. Otherwise you risk a wheel well over temp. Lots of stuff in there you don't want getting too hot. So let it dangle keep it below VLGE and let the airflow cool the breaks before retracting the gear 

Edited January 4, 2022 by Jase T

[flying dog]

To digress - well, I posted the video above.

 

Believe it or not.

 

But I don't think they were sitting there telling that story and it is/was a lie.

 

[turboplanner]

On 16/12/2021 at 7:15 AM, Bosi72 said:

By the same analogy why Undercarriage if large % of RAA aircrafts have fixed gear? Why Pitch when % of aircrafts have fixed prop.. 

 

Checklists are here to help because we are humans and we make mistakes. BUMFOH, PUFT, TMPFISCH, CFMST, FMOST etc.. are not in any CAO, CASR...  it is up to a pilot in command whether he/she wants to use them.

 

Back to question..

Agree, an aircraft can land flapless and without trimming.

However, applying full flaps when turning downwind to base would make a trip to threshold very long. I usually apply last stage of flaps on final (if required).. 

Finally, imagine after base to final,  when you push Pitch to fine, then you realise that Undercarriage was not extended earlier on a downwind (thanks PUFT), then apply last stage of Flaps, that would cause a lot of imbalance. Certainly Trimming would help with controlling the aircraft.

 

So the checklist PUFT, and in that particular order, make sense to me regardless whether I fly RAA or GA.

 

 

 

 

Probably not so applicable in RA, but in GA you might from time to time be flying a Retractable Undercarriage, and it's safer to have a standardised checklist than a whole lot of checklists where you also have to decide which one to use.

[facthunter]

 A "Positive Climb" situation should precede gear retraction. If it could be of some use to you. (Very long runway) a delay might be justified. Some planes have much more drag during the retract cycle than with gear down so take that into account if you  need to clear a near obstacle.

  Some "Ace of the base" types retract the Gear too soon as it looks cool, they think.  It's dead easy to settle a bit and make contact with the runway and that has happened a few times. Nev