Initial climb profile?

[bjornhall]

What is the best profile to use for initial climb?

I hear one school of thought saying you should climb at Vy to pattern altitude, while another idea is to climb with the horizon on the nose cowling for better forward visibility (gives about 85 - 90 KIAS and just under 1,000 fpm in a light 172S or 172R-180 on a cold day).

Will try both and eventually pick one, but was just curious what others are using!

[TheOddOne]

I hear one school of thought saying you should climb at Vy to pattern altitude,

Exactly. The clue here is in the word 'profile' If you move away from the figures given in the POH, unless you're leaving a completely flat field, how can you make sure that you have adequate terrain clearance. Also, by climbing at teh best rate, in the event of an engine failure, you've got the greatest possible glide range. It's a good idea to occasionally practice Vx, too, for those situations where you have significant obstructions. Another good reason for using Vy if you're flying circuits is to get yourself time on crosswind to properly trimmed for the circuit cruise, so that you minimise height changes while you're distracted doing your pre-landing checks etc.

Cheers,
TheOddOne

[IO540]

In GA, VFR, one should climb at Vy (best angle of climb) until clear of obstacles (generally this is a few hundred feet) and then trim forward for a speed which provides good engine cooling.

That will also give you good forward visibility.

[bookworm]

Exactly. The clue here is in the word 'profile' If you move away from the figures given in the POH, unless you're leaving a completely flat field, how can you make sure that you have adequate terrain clearance.

Eh? Climbing at max rate or max gradient offers no guarantee of terrain clearance. There will be many circumstances in which climbing at 1/2 max rate offers perfectly adequete terrain clearance. There will be others in which Vx won't get you over the obstacles.

The choice of speed is most affected by how much performance excess you have. In a light high-performance aircraft, frying the engine in a blind Vy climb is simply daft. In a heavily loaded basic type, you may need to keep it close to Vy to get the climb rate you need.

[FlyingForFun]

Does it matter?

This is one of those questions where everyone will have their own view, and at the end of the day they are probably all correct in the right circumstances.

Of course there are times when it is important to climb at best rate, or best angle, for terrain clearance. But if terrain is not an issue, you can climb at pretty well whatever speed you want. Some will go for best rate, some will prefer to lower the nose to give better visibility and improved engine cooling. Personally, I don't care.

However, what is important is that you decide what it is you're going to do and why you're going to do it. Deciding that, due to a combination of engine cooling characteristics, excess performance and the terrain on the climb-out, you're going to climb at Vy+20 is absolutely fine. However, getting airbourne without having thought about a plan or a profile and settling down to a speed of Vy+20 because it seems about right is not ok.

Personally, I usually follow my company's standard procedures, which call for a climb at 100kt (Vy=85, so that's Vy+15) and at a reduced power setting. However, there are times when this won't achieve the required climb gradient (usually an ATC climb gradient to comply with a Standard Instrument Departure, rather than terrain, but the principle is the same), in which case I will quite happilly climb for as long as necessary at Vy and at full power (which happens to be allowed by the POH for my aircraft, but isn't for all aircraft).

FFF
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[bjornhall]

Well, I like to see where I'm going, or more to the point, make sure there's nobody else going there at the same time... But I also like to be as high as possible as soon as possible to have more options when the engine fails... Getting higher faster to reduce noise, and keeping speed up to keep the engine cool are secondary considerations in the C172 I'd imagine...

To climb at Vy until having performed the after takeoff checks at 500 ft seems reasonable, will try that next time! :)

Until I get yet another instructor with a different opinion, that is... :ooh:

[Put1992]

I know he has said profile, but i would just lightly adjust attitude to maintain a good speed. But i would ask your instructor if i were you.

[homeguard]

For the ab-initio pilot to be taught the climb at best rate (Vy) makes most sense. They are learning a skill and will be expected to be able to fly their aeroplane at its 'best' later. Best angle, although rarely much different in small low powered aircraft should also be practised as a skill.

What you fly,Vx or Vy, as has been said, dosn't really matter save for engine management and care and to, somewhat obviously, avoid hitting anything

[bjornhall]

Thanks for all the advice!

Asking my instructors is what I always do; problem is, they give conflicting advice on this one... Which, on the other hand, is probably another good sign that it doesn't matter all that much!

[Lurking123]

Vy works well in the cct. Not least because it is normally pretty close to best range glide speed so if the donk fails, student just stuffs the nose down to maintain (re-achieve) the same speed.

Personally (a grass strip operator), Vx until about 100ft agl or above significant obstacles, then Vy until about 1000ft agl, then something that both gets me somewhere, lets me have a continuous look over the nose and keeps the engine sweet.

[Julian]

Its horses for courses, you fly the profile required for what you want to achieve, be it obstacles, cooling, SOPs, etc.

One thing you will find is different instructors will have different ways of doing things, glaring at you if you do them any differently. It does not mean to say what you are doing is wrong, just not what they are used to. Once you get more experienced and get pulled up on something you will actually be able to turn round and explain WHY you are doing it that manner and you may find that they actually learn something!

J.