Operating questions

[simonlowther]

Hi all

Sometimes best practice moves ahead of 75 year old POH's and other times the 'good ideas brigade' move even faster! Hoping to here some industry accepted thoughts (whatever that means) on operating our little airplanes...

Should I be leaving the carb. heat on after start during taxi?
Is it considered a good idea to pull the prop through as suggested in the manual before start on cold mornings, all starts, never?
Is it best to not use the park brake at all?

Not wanting to open any cans of worms just keen on learning.
Cheers

[6643]

I'm sure you'll get lots of opinions, so, I'll go first...

Should I be leaving the carb. heat on after start during taxi?

No. I would not. It allows unfiltered air into the intake, and, on the ground, that can be a very bad idea. Check the carb heat after your mag check, and I always go to full throttle after my mag check and before the takeoff run, just to confirm no carb ice.

Is it considered a good idea to pull the prop through as suggested in the manual before start on cold mornings, all starts, never?

Yes. I do it all the time. It gives you a quick compression check and, if you close the throttle completely it can even prime the engine for you. Just be aware that it could start (whenever you touch the prop.)

Is it best to not use the park brake at all?

It's best not to even have a parking brake, IMHO.

Not wanting to open any cans of worms

Too late!

[8474]

I agree with everything John says, although I must admit I don't pull the prop thru before starts. As to the parking brake, I completely removed the mechanism from the master cylinders, too many stories of the brake inadvertently activating in flight and the subsequent surprise at landing.

[6277]

Agree with John on everything. In addition, I always turn the fuel selector off about 30 seconds prior to reaching my hangar to allow the engine to run out of gas. If I time it right, the prop stops just as I pull up to my hangar door! Keeps the Stromberg from dripping and according to some, the cylinder walls are not "washed" by unburned fuel that is in the cylinder when the mags are turned off while the engine is still turning. After the engine stops, it's M&M time...Mags and Master off.

[6863]

I have in the past subscribed to the practice of pulling the prop through prior to engine start but am currently not doing that because I want to leave as much oil on the cylinder walls as possible. It's got a bullet proof battery and a good primer which works and a good oil pump so no pull through needed.

As for shutting down the engine with the fuel selector, I understand why Stromberg operators would want to do that, but I've noticed that the gascolator seals can get dried out and leak if the plane isn't flown for several weeks after shutting down with fuel selector. My Marvel Schebler with real mixture control shuts it off clean and dry leaving fuel in the gascolator to keep those seals moist and leak free.

What is a parking brake?

Lastly, my belief and adherence to some myths help me sleep better at night. One of those myths is that if I hoist the tailwheel onto a 30 inch tall bucket placed upside down with a plank fastened across the bottom of the bucket for strength, it discourages mice from inhabiting my airplane. Since 2006 so far so good. My airplane gets flown as well so I may never know if the bucket trick really works or not. Like I saiid, it makes me sleep better. Kind of like petting the dog just before bedtime.

[5469]

Hello,

I agree with the three John´s answers. I would add:

1. Carb heat.
I only use it on the ground during runup to make sure it works properly, and if icing conditions are within “Severe Risk” zone, to heat the carb applying hot air for 30-40 secs @ 1800 just before takeoff.
In all landings, when crossing the fence I push it to cold air, to avoid rolling with unfiltered air. One more advantage if you land in a cold air position is that if you need to go around, you are already set.

Lycoming has a detailed description of all this in pages 3-4 and 3-5 of the O235 engine operation manual. Is not Continental, but principles are exactly the same. I started flying with O235, then O320. We were taught that way.

https://www.lycoming.com/sites/default/ ... 0297-9.pdf

2. On the first morning start, I always pull the prop, with all due respect!

3. I also dismantled the parking brake mechanism.

Have a nice Sunday.

Just read your Mice Trick, John. A pleasure to read you, as always. And nice idea about "better sleep"

[a64pilot]

What does pulling the prop through supposed to do? Possibility of a hot mag always has me treating that prop like a loaded gun.

Several aircraft, Maules for example have had nose overs from inadvertent parking brake application, quite an exciting landing I’d assume, a Maules parking brake is identical to ours, then we all know to never set one on a hot brake and why, so I guess your supposed to just hang out an wait for them to cool? I just toss chocks under a wheel myself.
I disabled the parking brake on my Maule and my 140, I haven’t the Mooney because the outcome isn’t as severe, but I have never and expect to never use it. I don’t even know if it works. Who would trust their aircraft to a parking brake anyway?
On run up just prior take off I run the carb heat for a long time to make sure if there was any ice it’s gone prior to takeoff, and I too push it in on short final because of non filtered air. Why would you taxi with it? It won’t really work at very low power setting as the exhaust isn’t hot.
I have a helicopter story to go with that.
I always run mine out of fuel too, but do not believe killing it with ignition does any harm, how many millions of engines get shut off with ignition? Only aircraft get killed with mixture.

I don’t concur with Lycomings recommendations for carb ice on our little Conti’s, I always pull carb heat about the time I reduce power on downwind, our little Continental’s got the nickname ice machines for a reason.

[simonlowther]

thanks to all, some good info and ideas in here.

Cheers
Si

[8014]

"Rosebud" has the parking brake knob but it's not connected to anything. There's no logbook entry but I suspect that it was disconnected/disabled in the 80's during a restoration. There are lots of stories out there about 120/140 parking brake landing mishaps so I'm happy carrying PVC pipe wheel chocks instead.

Tony