10000ft in a Warrior
 

I'd quite like to take a PA-28 up to 10000ft, just to try something a bit different, and for the view :ok:, and I'm wondering what implications I need to consider. While doing my PPL I was briefly taught leaning but have never tried it in practice, would you lean every couple of thousand feet in the climb (reduce mixture untill rpm stops increasing, and richen the mixture slightly)?

Also, in terms of airframe icing, am I right in thinking this is only a problem if there's visible moisture? And finally, during a decent, is there anything wrong with an idle decent with carb heat at the high end of the green arc speed, with an engine warm every so often, or would the high airspeed cool down the aircrame too much, as I believe happens to some gliders?

Many thanks

Mixture lean maybe a couple of times during the climb, and again when at cruise (just gradually for the RPM peak, then as per your SOPs - some schools try and help the engines last longer and teach to run slightly rich). Icing only a problem with visible moisture. I've flown a Warrior many times over the Rockies at 11,500 with no problems...enjoy the smooth ride! Oh another thing...expect the rate of climb to dwindle very quickly above 8000ish feet!

Ben

Check the manual for cruise settings and leaning for 10000 feet as well as climb settings and use those.

10000 feet in itself is not relevant to icing, temperature is, pedantic maybe but you can takeoff on a hot day of 32 deg C and be well in the plus at 10000feet yet takeoff on a cold 4 deg C day and have icing problems at 4000 feet and none at 10000 feet.

In most circumstances icing will not be a problem unless flying in visible moisture ie clouds.

No do not just close the throttle and descend. Try for a managed cruise power descent or reduced power descent rather than closed throttle.

Monitor the manifold pressure which will increase in a normally aspirated engine as you descend and reduce accordingly.

Monitor the speed in the descent keeping it in the green arc. Only go into the yellow arc if the air is smooth and you are sure it will stay that way.

IAS will decrease as you climb TAS will increase so be aware of that fact.

As CanadaAir stated your climb rate will decrease as you climb higher do not be tempted to pull back chasing the climb rate or you will get into a high angle of attack high drag situation. Hot days and heavy and you may struggle with a normally aspirated engine so precise flying is more important at altitude.

Finally while you should not have a problem at 10000 feet with lack of oxygen, a small minority do. Above 5000 feet and night vision suffers which shows there is an effect how much depends on your fitness lifestyle and natural tolerance.

If unsure go for your first high altitude climb with an instructor.


Pace

I did it once in a PA28-140. Took forever to get up there, and climbing into a headwind, I think I was down to a groundspeed of like 50 knots or so at the top of climb. It was a crystal clear day and the view was awesome.

I don't recall my leaning procedure, I did it quite a few years ago. I do recall the climb rate was pretty crappy nearing the top. And coming down with power makes a lot of sense.

Lean as suggested, check your airspace (even if controlled, they'll probably give you a clearance of you ask), avoid moisture, and go for it! As mentioned, for the sake of the engine, do not get up there, and close the throttle. Presuming this is a fixed pitch prop aircraft, once you reach to top, plan to reduce RPM at a rate no greater than 100 RPM per minute, as you start down. If Constant speed, 1" MP per minute. Descend with some power on, and the slowest practical airspeed, to reduce the cooling of the engine, which will now be producing little heat in the cooler air. By caring this way you are preventing "shock cooling" and the person who pays for the maintanence of the engine will appreciate it!

During a flight test for MOGAS, I once had a normally aspirated Cessna 180, with a carburettrd engine, to 20,800'. At that altitude full power was only about 40% of sea level, and the maximum attainable airspeed was stall speed. I regularly fly longer routes in my Cessna 150 at 9,500'/10,500' when the strong tail wind becomes an advantage.

Have fun, Pilot DAR

If you want to get down quicker, while keeping some power on, you can always use flaps to dirty it up - at suitable airpseeds of course. I personally see nothing wrong with coming back to idle *once the temps are right down*, just clear the engine every now and then.

The glider problem isn't so relevant to you - what we have a problem with is cracking the gelcoat (no gelcoat on a warrior..) Having been up there for a long time (maybe 3-5hrs) and truly cold-soaked the airframe, someone comes down rapidly - perhaps 1000fpm or more with the airbrakes out. The skin warms and expands first, while the core is still cold and shrunk.. hence the gelcoat damage.

Lastly a word on perception. If you've not gone high much, you'll find that after tooling around at 10,000 you'll feel like you're in the weeds at 2000, and want to flare at circuit alt. Just keep an eye on it, and believe the clocks.

A bunch of nuts in the C120/140 association had an interesting "how high have you gone" thread, complete with some good pics:

http://www.cessna120-140.org/forum/viewtopic.php?t=2816

Some of the 120/140's don't have mixture control. Others have a hokey mixture control.

-- IFMU

Nice trick if you can do it in a PA28 WARRIOR (No MP gauge)

Got a 1200cc VW powered Druine Turbulent up to 10k. Took a long time, took longer to get down, pulled off the power - cyl. hd. temp disappeared off the clock - can't do that, restored some power and temperature and stuffed the nose down - Vne 104 kts. cyl. hd. temp. also disappeared. Eventually came down with some power and speed to retain some positive cyl hd. temp.

Might take you a while to get there :uhoh:

The only benefit in climbing to such a high altitude would be reduced fuel burn & a decent tail wind (if any) over a long flight, say >500nm. For a shorter flight there's not much point in wasting time & fuel climbing up there.

Also depends if you have nice enough weather in the first place to get to 10k!

Must be a bit chilly in a Turb though :uhoh:

Smithy

That's really not a good suggestion if there's any chance of flying through rough air on the descent.

With regards to leaning on a climb; wouldn't you always want the mixture to be lean of peak as compared with rich of peak?

The revised LAA flight test schedule for initial permit issue now requires a V(y) climb for 5 mins.

Found myself and air test observer just short of 10 000' at the end of Dec. No heater so it was cold - vis was wonderful, in cold clear blue sky, I swear I could see Holland, Germany and possibly Scandinavia!!:ok:

You'll find at higher levels, you need to fly the book speed accurately to get any climb out of her. Also once in the cruise, note the difference in IAS and TAS (use the little white adjustable ASI scale to compensation for altitude/temp). You learn about this in the PPL but until you get to 10,000 feet and see the speed indicating 90 knots when you are used to it reading 110kts that you realise that the books were right.

Don't forget to set 1013.25 on the altimeter as you pass 3,000 feet in the climb and report your height in Flight Levels.

If you want to get down quicker

I don't recommend this either. Apart from the risk of shock cooling the engine, it's not good airmanship to descend quickly as it hurts your ears. I usually descend from high levels at just 500fpm in unpressurised aircraft and the technique I use is to pitch forward for -500fpm, let the speed build up towards the yellow arc then throttle back so you've got some power on all the way down to avoid shock cooling.

Adjust your speed for smooth/rough air accordingly.

The distance to the horizon is 1.25 times the sq root of the height in feet so at FL100 you should be able to see 125 miles (vis allowing). Also at that height you'll almost always be above any inversion and the general haze of lower levels and in a standard atmosphere, it will be 20 degrees colder up there too, so wear a woolly!

While doing my PPL I was briefly taught leaning but have never tried it in practice

I had the same experience in my PPL and frankly it's shocking behaviour on the part of the schools. With the high cost of fuel, it's negligent to leave the mixture on full and it's not too kind to the engine at high level. How anyone can fly a plane and not use a primary engine control lever beats me. It's not your fault, but I do suggest reading up on the technique both with/without CHT/EGT gauges. Even an approx inch or so is much better than leaving it all the way rich.

Finally in the long descent at low power settings, even clear of clouds, carb ice is a real potential issue, so make sure you use carb heat according to the book.

In unsure, check the POH about leaning. For a Cherokee, I seem to recall it says don't lean below 5000 feet at more than 75% power.

What peak are you talking about? If you mean peak EGT, definitely not!
1) in any event, you'll struggle to get all four cylinders of an O-320 lean of peak;
2) even if you could, the power loss would make the long, slow climb even longer; and
3) because you won't be able to achieve a sufficiently lean setting, at least half the climb will in the 'red box' avoid area for mixture settings.

What you really want to do, above the first few thousand feet which should be at full rich, is climb at peak power, circa 100degF rich of peak egt.

You can lean at any altitude as long as you are under 75% power.

I was taught about leaning by my instructor; I'm not sure why other schools don't bother.

Chilli Monster

Thanks for correcting that posted my piece late last night and have flown too many aircraft with MP gauges :)

Pace

A standard Warrior doesn't have an EGT gauge so leaning ROP/LOP is virtually impossible. It also doesn't have a MAP gauge or fuel flow gauge. The only gauge you have related to engine performance is the RPM gauge.

This is from the PA-28-161 Cadet POH:

This suggests that during the climb you should be running full rich all the time. However, if you look at the performance charts for a climb, then you'll find that the numbers in it are based on "lean mixture per Lycoming instructions". But these instructions are not included in the POH... In fact, later on (in the Airplane Description) another reference is made to the Lycoming Operating Manual.

Personally what I would do in a Warrior (no EGT) is simply lean for maximum RPM, once above 6000 feet, to obtain best climb performance.

Oh, and if you look at the performance chart for the descent you'll find that if you follow the instructions, the descent from 10.000' takes about 12 minutes, or a little over 850 fpm. This might be a bit uncomfortable. As someone else suggested, you'd better aim for about 500 fpm, particularly if you have passengers.

Oh, one more thing, don't forget to factor in the time for climb/descent. It's not a 20 minute jolly. I reckon it will take around 15-20 minutes to get up there and 20 minutes back down again. 20 minutes in the cruise and you've got an hour logged.

Don't forget to consider the winds aloft as well. They can be quite strong at those levels (50-80kts) when it's fairly benign on the ground. With a groundspeed of 20 knots into wind, it will take you a long time to get somewhere!