Backcountry Pilot

[Skystrider offline]

This thread was split from a review of the McCall Mountain & Canyon Flying Seminar. See the original thread.
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Thanks for the report Sojorrn.

Boy, not cycling the prop caught me by surprise! Heck, that is number four on the engine check list in the M5 180C Maule Flight Manual. I have also been taught to do that by a high time Maule instructor. How can cycling the prop damage it? Did they give you any specific reason?

A curious idiot wants to know!

[skybobb offline]

Nice write up and I will be looking forward to seeing you at JC one of these days. Bob

[Green Hornet offline]

Not Prop cycling. It surprised me as well ( check mate has it on the check list and that is the way I was taught I never seen the interconnect between prop and engine parts but they are convinced that at 2000rpm when engaged it could damage the interface mechanism. I put that point on the site to prompt more discussion from the more learned among us but there primary point is that the governor supplies the oil.

[Hammer offline]

What other pre-flight advice did they give?

[mr scout offline]

Prop cycling. they are convinced that at 2000rpm when engaged it could damage the interface mechanism.

I call BS on that one, although I cycle the prop at about 1400 when cold to move some oil around.

The prop gov. is about as primitive as they come much like an old steam engines.

When you cycle it you should be looking for a brief drop in oil pressure and a rise again. Without that you could have a problem. What do they think happens at 27 or 2800 rpm when you pull it back.

Or were they telling you not to bring it all the way back? When cold?

[mtv offline]

Sojorrn,

I'm with Scout on this one--these guys, if that's what they are teaching, are just flat wrong. EVERY checklist you'll ever see will tell you to cycle the prop prior to FIRST FLIGHT EACH DAY.

IF what these guys are saying is that it isn't necessary to cycle the prop every time you start the engine, I'd agree. If they are suggesting that you can do a lot of damage to the blades by cycling the prop at high rpm over unprepared surfaces, I agree as well.

BUT, you should ALWAYS cycle the prop at least once prior to the first launch of the day.

Now, HOW you cycle the prop is another deal: You should never drop more than a few hundred rpm during a cycle. Some folks pull that prop lever to the coarse pitch stop and leave it there, till the engine loads up. That is not necessary, and is not good operating practice.

The notion that you will actually damage the propeller mechanism by cycling it is totally bogus. If that were true, you sure wouldn't want to move that prop control in flight, would you?

I've discussed cycling propellers (specifically on an O-360 Lycoming) with Lycoming, specifically asking them if there is any real need to cycle the prop three times, as virtually all checklists call for. The engine reps's response was that that is considered the proper procedure, and we should do it. I then asked Hartzell, and their response was the same. If there was any danger of prop cycling damaging the prop or engine, I think these folks would have brought it up.

Damage your aircraft someday because of a prop issue, and try telling the FAA that these folks taught you not to cycle the prop, and see what the FAA, Lycoming and Hartzell all tell you in response.

MTV

[Green Hornet offline]

The disc brakes as we were taught can be inspected but what I did not know is that the metal piece that is parallel to the dics, closer to the aircraft can be used as a measuring guide. If your disc is less than half the width of this piece you need new brakes.
What is the most important gage in the aircraft?
ANS. Oil Pressure
Run up check the mag closest to the off switch first then go back to both, then check the next mag and return to both. reason = a lot less likely to take off with one mag.
Do not use Nav lights because they tend to sink amps and anti Collision can be seen better.
Shutdown is also different from the way I was taught.
SLIM = Switches, Lean, Ignition, Master. Why because you can do damage to the master electronics's by turning off while the ignition is still on.
Of course some of this is my problem due to it not sinking in the first time but I am glad it was brought to my attention.

[Green Hornet offline]

They did mention the blade damage as well during prop cycle. but they were adamant about not doing it period . I questioned it several times . They did mention that run up on a back country strip was a no no because of rocks etc.
One of them said propr cycle was a hangover from radial engines??

[retired user offline]

I guess I knew the day would come when I would have to agree with MR Scout and now it has.

I for one, would really like to know that when I start backing out the prop after TO it's going to work and it's not going to spew oil all over the windshield. I have always cycled the prop for 200-300 rpm drop and push it back in, one time. It shows it works and it shows it doesn't leak. I'm not sure how else you could verify either without cycling...

[Hammer offline]

Any chance they were cautioning against pulling the prop through by hand prior to starting the engine, rather than cycling the prop during the run-up? That would seem to fit better with the radial engine connection.

[Green Hornet offline]

This is the men who informed me of the prop cycle no no
Bart Welsh Email Bart

Wellington, Nevada

Bart started flying at age 18 and has accumulated a vast amount of flying experience. He is a Commercial Pilot, an Instructor in both single and multi-engine, and an Instrument Flight Instructor. He has held an A&P Mechanic License for many years and possesses an Inspector Authorization (IA). He is also an FAA Safety Counselor. Bart is one of our original Flight Instructors and has been with McCall Mountain/Canyon Flying Seminars since the program's original planning.

Bart is the former Director of Aeronautics for the State of Idaho and has spent many years working to develop and preserve the Idaho network of backcountry airstrips.

He owns a Cessna 180, a Cessna 150, and a Stinson 108-2 (Voyager). He has flown nearly 6,000 hours with about 1,200 instructing, and over 3,000 in tail-wheel aircraft. Bart has been flying in the backcountry as well as teaching in the backcountry for over 25 years. Teaching is his passion. He holds a BA, MA and Doctorate degree as a Teacher and Vocational Educator.

At this time, Bart operates a small flight training operation in Nevada and Idaho, to introduce youth and adults to aviation at virtually no cost. Students that are interested in learning to fly must pay only for the fuel and help with labor to maintain the airplanes.

If you would like to question the input here is his email

[email protected]

Here is the other man

Captain Holbrook Maslen Email Holbrook

Boise, Idaho

Holbrook holds air-transport pilot, instrument instructor, multi-instrument instructor, Part 135, and A&P certificates. He has over 23,000 hours of experience, including over 2,000 hours in the Idaho backcountry. He started flying in 1949 and served 3 years with the Army Paratroopers and 10 years with the LAPD, where he flew helicopters. He also retired from United Airlines with 36 years of service.

Holbrook owned a skydiving school and a FBO in southern California in the 1960's and later started a FBO in Honduras. He continues to compete in the Reno Air Races and plans to fly a Formula One and his Unlimited in September.

He currently owns a Cessna 180, 185, and 195; a Russian Yak3; a Beech 18; an L5; and a helicopter. He is also restoring several other projects for his museum, “AEROPLANES OVER IDAHO.” He recently restored a 1937 Military Harley Davidson and a Model T.

Holbrook will roll out the red carpet for anyone donating planes and military memorabilia to the museum.
Email:

[email protected]

[Green Hornet offline]

Mr Scout,
No, I let the rpm drop 500 rpm and then back to 2000 rpm 3 times.
I knew this would raise eyebrows but with their credentials and my lack of I was not in a strong position to argue.

[wannabe offline]

My Ole Grandpappy used to tell me, "Son, don't go gittin into no "pig fights", cause everyone gets $h!t on em, but only the pig enjoys it."
Then there is the old "saw" about "Fools rush in, etc.
But in the hopeful interest of a bit-o-balance!

The class does not advocate a depature or "violation" of any POH.

What they have found over time is that too many people keep doing the same old procedure / process regardless of the SITUATION. (situational awareness?) In other words, they have seen too many props, therefore too many days of flying, ruined by the CONSISTENT process of doing a full run-up on un-paved strips with ruiness results. This has, unfortunately, been empirically demonstrated enough times for them to suggest a slight change in procedure for unimproved strips.

I know an aging profesional ground school instructor, CFII, etc in Palo Alto. who now warns that one of the three major ways for the pilot to INDUCE DETONATION is to run the prop too slow with the MP set too high. That is the direction that we are headed in when we run up the RPM, and then pull out the prop knob. As I remember it, in my check out, in what used to be called high preformance, complex aircraft, there was, even then, a STERN warning of just barely letting the RPM drop, and then quickly back in with the prop knob to avoid engine damage. Something to do with cylinder pressure. Somethin like starting your old truck out in low gear and then jumping to high gear with the gas pedal stomped on the floor.

The reference to radial engines has something to do with them having, (remote), oil sumps measured in gallons instead of qts., and that it did take longer for the oil to warm up and had further to travel. I, unfortunately, have no radial time. Been looking at a Fairchild 24 though.


As far as finding out if the prop is going to work, and it seldom fails. When you start to unwind it, if it does not want to slow down, just simply, either, turn around, or, if the fuel allows, hop on over the ridge to the nearest mechanic.

The basic message is that in a "dirty" environment, you may want to modify some of the process a bit. One suggestion is to shut off the carb heat on short final to minimize ingestion of dirt, grass, rocks, gravel, elk meat, etc. Of course, if ya like elk meat?!?

Piggly-Wiggly out

[Green Hornet offline]

Chris,
Extremely witty I really don't see what pig shit has to do with this mechanical question. We are not talking liberal vs communist.

"The class does not advocate a depature or "violation" of any POH. "

Bart, Art and Holbrook all said that Cycling a prop was not necessary. As a matter of fact they were adamant and used the anecdote about the A & P who asked the guy if he cycled his prop, where the man said " yes" proudly. and the mechanic replied " You think that is a good thing?
Every day at run up with an different CFI I questioned their point of view regarding prop cycle. I got the same answer it does nothing for the prop and if it is bad you will see oil on your windshield before take off.
You sat through the class and not once did you question there position on this subject.
Not once did they say this was for backcountry strips only except for run up.
They did admit that this was the first year they taught this as a input to students.

[mr scout offline]

From the Hartzell boys comes this,

Perform engine start and warm-up per the Pilot's Operating Handbook (POH).
Cycle the propeller control throughout its operating range from low to high blade pitch (or as directed by the POH).
Repeat this procedure at least three times to purge air from the propeller hydraulic system and to introduce warmed oil to the cylinder. NOTE: Pitch change response on the first operation from low to high blade pitch may be slow, but should speed up on subsequent operations.
Verify precise RPM control from low pitch to high pitch for various engine power ranges.

Bill one of the great things about flying is you meet so many people and hear so many opinions.

The key is weeding out the chaff, as presented they have no basis for the argument.

If they dont want you to sit on a gravel bar and cycle your prop that is good advise.

If they dont want you to yank it all the way out at 2100 rpm when its cold that may also be reasonable advise.

If they never want you to do it, then they may make it into the floydism book.

I doubt all of them together have 1/2 as much time as Hartzell when it comes to proper operation of a prop.

[Green Hornet offline]

I knew this would bring up a debate when I posted it. I had my doubts all the time they were saying it but not enough knowledge to push back. I emailed them to see what kind of response I get. I told them I stirred up quite a ruckus with the community. It should be interesting to discuss. anyway mr. Scout I appreciate the research.
BTW are you the Floyd in Floydisms ?

[mtv offline]

Again, I specifically asked Hartzell whether cycling the prop prior to first launch of the day is NECESSARY. This was posed at Sun N Fun three years ago, and two prop experts were there to answer. Their answer was unequivically YES, you should cycle the prop at least prior to the first launch of the day.

My next question was, is it necessary to cycle the prop THREE TIMES, since this seems to be the magic number in all POH's. Their answer, once again, was YES.

If these folks feel that they have to dumb down procedures to accomodate their clientele, maybe they should work a little harder to teach students the right way to do things, in different scenarios.

On a gravel bar, first launch of the morning, I don't run the thing up to 1700 or 2000, as the POH's recommend. It'll cycle at 1300 to 1500. Cycle it once or twice, and go.

I've seen props that went ballistic on a takeoff, as in a runaway, but never spit ANY oil.

And, in a lot of REAL out of the way places, once you commit to a takeoff, the notion of just circling around to land again, cause your prop isn't functioning will just flat get you KILLED. I'm amazed that people who routinely deal with high density altitudes would even offer that.

Don't believe us, try calling HARTZELL yourself--explain the scenario, and see what THEY have to say. They build the dang things, and repair them, and pick up the pieces, and get sued if something comes apart in there.

This whole discussion reminds me of a Cub pilot who proudly discussed "THE" off airport takeoff technique, as taught be a "Bush Flying Expert", which was match the aileron deflection to the flap deflection, and hold that stick position as you accelerate. When the plane is ready to fly, it'll lift the wing with the down aileron... Good grief, what a terrible technique, but sometimes it seems that these outfits feel like they have to teach their customers some "trick" or other to justify their fees.

Call Hartzell.

MTV

[M6RV6 offline]

Hey all the pigs like to roll in it.
Here's my 2 cents worth??
When it's warm (above 40 ) I don't cycle the prop, if it doesn't move or leak you have a fixed pitch climb prop. Thats OK if your not going far.
If it's on a Round Motor, after the engine is warm and you've had your second cup of coffee, nows the time to cycle it, especially if you have 2 of them.
On the anything that has a feather position (usually a twin) you damn sure feather it as that is knida important to know if it will if you happen to lose one!!
All told in about 6000 hrs I've been real fortunate and not had a prop do anything bad.
They do loose paint in the water, snow, rocks and runway lights, but I don't think that is the fault of the Prop. Usually the fault is with the right hand of the PROP NUT!
It's nice to hear all the views, thats why we are here.
Thanks to all GT

[retired user offline]

MR Scout,

Where are we now ? 279 ?

[mr scout offline]

MR Scout,

Where are we now ? 279 ?

Last count was 277.5 but I slept since then