Three rules of Aviation

[dmccormack]

Sometimes the performance tables are optimistic (as are the W&B figures). And every once in a while you mentally think you've brought gear up when you haven't (oops).

I put VG's on my Commander and it was one of the best mods I made.

True, that.

...or non-existent (older airplanes).

I learned the almost hard way 65 HP is reduced to 45 or so with carb heat IN.

The A36 I flew had VGs -- that thing simply would not stall -- just mush.

 

[wsuffa]

True, that.

...or non-existent (older airplanes).

I learned the almost hard way 65 HP is reduced to 45 or so with carb heat IN.

The A36 I flew had VGs -- that thing simply would not stall -- just mush.

Pretty much the case here. It'll stall under the right conditions, but it's pretty hard to do, esp. power-on (it is a very, very uncomfortable angle).

I was out practicing slow flight one day w/flight following - ATC called to ask me what I was doing as he showed zero groundspeed.

 

[Mtns2Skies]

Boost makes the world go 'round, after all.

MORE BOOST!

You're not from Colorado.

I will be shortly, and from what I've heard, performance is going to the gutter.

 

[dmccormack]

Pretty much the case here. It'll stall under the right conditions, but it's pretty hard to do, esp. power-on (it is a very, very uncomfortable angle).

Yep -- feels straight up. A glance out the side helps reorient, but a WOT stall angle is ridiculous.

 

[poadeleted20]

Sometimes the performance tables are optimistic

That's why my personal standard is to stick to runways whose length is at least 150% of the book-computed 50-foot obstacle takeoff distance. Yeah, it's conservative, but it reduces the strain on my cardiovascular and digestive systems.

 

[poadeleted20]

Yep -- feels straight up. A glance out the side helps reorient, but a WOT stall angle is ridiculous.

Not at 10,000 DA, which is one reason I teach folks power-on stalls at reduced power settings (like 75%) when the DA is low where we're training, and require recovery with pitch alone -- they get to see what a takeoff/departure stall at Leadville is like with a full load. They are usually shocked at the low pitch attitude when the stall occurs compared to the "stand on your tail" situation when they unrealistically do a full throttle stall in a 172 with two people and half tanks.

 

[midlifeflyer]

Not at 10,000 DA, which is one reason I teach folks power-on stalls at reduced power settings (like 75%) when the DA is low where we're training, and require recovery with pitch alone -- they get to see what a takeoff/departure stall at Leadville is like with a full load. They are usually shocked at the low pitch attitude when the stall occurs compared to the "stand on your tail" situation when they unrealistically do a full throttle stall in a 172 with two people and half tanks.

They's be even more shocked by a real takeoff in Leadville in a 160-180 HP 4-seater.

 

[dmccormack]

Not at 10,000 DA, which is one reason I teach folks power-on stalls at reduced power settings (like 75%) when the DA is low where we're training, and require recovery with pitch alone -- they get to see what a takeoff/departure stall at Leadville is like with a full load. They are usually shocked at the low pitch attitude when the stall occurs compared to the "stand on your tail" situation when they unrealistically do a full throttle stall in a 172 with two people and half tanks.

In HP airplanes the PTS only requires 65% power, so I usually demonstrate one WOT stall (if the pilot's willing).

But a high DA stall demo is a very good idea.... I'll have to add that to my Instructors Bunch of Scary tricks!

I'm also a fan of demonstrating power off recovery with pitch only -- despite the FAA's insistence on simultaneous power and pitch.

 

[flyingcheesehead]

I will be shortly, and from what I've heard, performance is going to the gutter.

Takeoffs and climbs will be markedly slower than you're used to - Several seconds added to the takeoff roll in the 182. At Leadville (with a DA of 12,200 feet ) it took 2000 feet of ground roll, and we were probably 100-200 pounds under MGW.

 

[gismo]

I have - A Cherokee 140 near gross weight at 105 degrees F on take off at Baton Rouge. Encouraged me to add some performance mods to improve take off an climb.

I had one departure last summer from a short soft grass runway that had me wishing I was carrying less fuel. I had more than I needed to have a decent reserve at my destination (less than one hour away) and was carrying extra due to getting more fuel than I asked for prior to arriving at the short strip. The gross weight was within acceptable limits and the takeoff went as planned (consuming most of the 1800 ft runway) but I would have preferred to be another hundred pounds below MGW.

There are certainly times when extra fuel provides additional options and improves safety, but IMO this is NOT universal. Knowing how much fuel you have at all times and keeping track of options for landing to add fuel is far more important to me than departing with the maximum amount of fuel I can carry.

 

[Clark1961]

Not at 10,000 DA, which is one reason I teach folks power-on stalls at reduced power settings (like 75%) when the DA is low where we're training, and require recovery with pitch alone -- they get to see what a takeoff/departure stall at Leadville is like with a full load.

Funny, in the Dakota at 10,000 a power on stall is still a tail-sitter...

 

[Graueradler]

There are certainly times when extra fuel provides additional options and improves safety, but IMO this is NOT universal. Knowing how much fuel you have at all times and keeping track of options for landing to add fuel is far more important to me than departing with the maximum amount of fuel I can carry.

Lance said it much better than I did. My feelings exactly

 

[gismo]

Funny, in the Dakota at 10,000 a power on stall is still a tail-sitter...

Maybe not if you're at MGW and the temp is 15C above standard?

 

[wsuffa]

There are certainly times when extra fuel provides additional options and improves safety, but IMO this is NOT universal. Knowing how much fuel you have at all times and keeping track of options for landing to add fuel is far more important to me than departing with the maximum amount of fuel I can carry.

Agree - this is one reason I love having a fuel totalizer.

 

[Clark1961]

Maybe not if you're at MGW and the temp is 15C above standard?

Maybe. Mostly I practice power on stalls at 25" and it's hard to keep the deck angle below 30 degrees and get a nose drop. If I go to 41" then I suspect it'll just hang there for a long time but I've never ridden it out 'cause I know the CHT will spike into the "really bad" region.

As a side note, last time I departed LXV the climb rate was north of 1,000 fpm and it was July. Okay, early morning July but it was a really nice climb.

 

[gismo]

Maybe. Mostly I practice power on stalls at 25" and it's hard to keep the deck angle below 30 degrees and get a nose drop. If I go to 41" then I suspect it'll just hang there for a long time but I've never ridden it out 'cause I know the CHT will spike into the "really bad" region.

As a side note, last time I departed LXV the climb rate was north of 1,000 fpm and it was July. Okay, early morning July but it was a really nice climb.

Did you forget to mention that this is a Turbo Dakota? Neither 41" MP nor 1000+ FPM climbs above 10,000 DA are plausible in a NA Dakota, AFaIK.

 

[PilotAlan]

I'm also a fan of demonstrating power off recovery with pitch only -- despite the FAA's insistence on simultaneous power and pitch.

YES YES YES!!
Doing a couple of those is a real eye-opener about airspeed control with an engine out. I made several mental changes to my emergency procedures after that...

 

[PilotAlan]

There are certainly times when extra fuel provides additional options and improves safety, but IMO this is NOT universal. Knowing how much fuel you have at all times and keeping track of options for landing to add fuel is far more important to me than departing with the maximum amount of fuel I can carry.

I understand your point, and agree there are no hard and fast rules.
That said, the question is what is your default setting?

Unless there's a specific reason not to, I fill the tanks.
The most common cause of planes going down is fuel exhaustion. I know none of them planned on running out of gas.

 

[gismo]

I understand your point, and agree there are no hard and fast rules.
That said, the question is what is your default setting?

Unless there's a specific reason not to, I fill the tanks.
The most common cause of planes going down is fuel exhaustion. I know none of them planned on running out of gas.

My plane holds 140 gallons which is good for 5.5-6 hours and 850-1000 nm (no reserve) and that's a lot more than I consider useful for a 1-2 hour flight so I will often depart with less than full tanks, especially if the price is high where I'm at compared to where I'm going.

The point I was trying to make earlier is that unless the engine quits shortly after takeoff, running out of fuel in flight has little or nothing to do with how much fuel was in the plane when it took to the air and everything to do with how much of the available fuel was consumed in flight. In an airplane that only holds enough fuel to fly for 3 hrs and 250 nm before nothing but fumes remain in the tanks with proper leaning, departing with full fuel won't prevent exhaustion if the pilot departs on a flight that was planned to take only 2.5 hours but due to unexpected weather ends up taking 3 hrs. IOW preflight fuel planning should be considered as more of a means to decrease the chances of needing an early stop for fuel rather than a way to insure the flight will be completed before the fuel runs out. That (completing with fuel left over) requires a continual assessment of the fuel situation during the flight. Heck even if you departed on a flight you expected to take 3 hours with only 2.5 hours of fuel in the tanks could be a successful flight if only you realize the insufficiency of the fuel supply in time to land at some closer airport than the planned destination.

 

[Clark1961]

Did you forget to mention that this is a Turbo Dakota? Neither 41" MP nor 1000+ FPM climbs above 10,000 DA are plausible in a NA Dakota, AFaIK.

Naw, I've mentioned it many times in the past and by service bulletin I am required to refer to it as a Dakota (all "turbo" markings removed)... At least you did catch on. You do get points for that.:smile:

I'm just pickin' on one of the "experts" about their overly generalized claims...and their rather obtuse stance on particular subjects.

 

[Everskyward]

I am required to refer to it as a Dakota (all "turbo" markings removed)...

I can see how some line guys might mistake it for a jet.

 

[Clark1961]

I can see how some line guys might mistake it for a jet.

Hey, it's just a small Meridian with a really short nose, right?

I really did laugh out loud when I read the SB....just more help from our friendly, taxpayer supported, folks at the FAA.

 

[flyingcheesehead]

Hey, it's just a small Meridian with a really short nose, right?

I really did laugh out loud when I read the SB....just more help from our friendly, taxpayer supported, folks at the FAA.

You're kidding - There's really an SB to remove "turbo" markings?

 

[flyingcheesehead]

Unless there's a specific reason not to, I fill the tanks.

I will often depart with less than full tanks, especially if the price is high where I'm at compared to where I'm going.

Which sounds like a specific reason to me.

It is a reason I've used many times, but I'm in the I-fly-a-plane-with-6-hours-of-fuel camp.

 

[Clark1961]

You're kidding - There's really an SB to remove "turbo" markings?

Unfortunately I'm not kidding. It's SB 798 issued 11 Dec 84. In addition to a list of models the SB specifically states that it covers any and all Piper piston powered aircraft that had "turbo" in paint or decal on the exterior. Compliance time was 100 hours operation or 90 days.

 

[flyingcheesehead]

Unfortunately I'm not kidding. It's SB 798 issued 11 Dec 84. In addition to a list of models the SB specifically states that it covers any and all Piper piston powered aircraft that had "turbo" in paint or decal on the exterior. Compliance time was 100 hours operation or 90 days.

So, any Piper Comanche, for example, that still said "Turbo" on it would technically not be airworthy?

What if it said Trrrrrrrrbo?

 

[Clark1961]

So, any Piper Comanche, for example, that still said "Turbo" on it would technically not be airworthy?

What if it said Trrrrrrrrbo?

With that attitude you may make a fine lawyer. However, I suspect that your chances of obtaining and holding a government position are at least slightly below average.

I'm thinkin' that since it's an SB that my Dakota is still airworthy even though the "Turbo Dakota" name was added when it was repainted in 99. Ok, I better rephrase that: I'm thinkin' that since it's an SB having "Turbo Dakota" on the outside of my aircraft does not affect it's airworthiness. However, I'm not an expert on SBs and airworthiness even though yadda, yadda, yadda.

My question is: why don't two "100LL only" placards over-rule one "Turbo Dakota" sign?

 

[flyingcheesehead]

With that attitude you may make a fine lawyer. However, I suspect that your chances of obtaining and holding a government position are at least slightly below average.

Hehe. I agree.

I'm thinkin' that since it's an SB that my Dakota is still airworthy even though the "Turbo Dakota" name was added when it was repainted in 99. Ok, I better rephrase that: I'm thinkin' that since it's an SB having "Turbo Dakota" on the outside of my aircraft does not affect it's airworthiness. However, I'm not an expert on SBs and airworthiness even though yadda, yadda, yadda.

Ah. OK. Really, I'd think the Hoover nozzles, etc. would have solved this by now.

My question is: why don't two "100LL only" placards over-rule one "Turbo Dakota" sign?

Same reason two brain cells don't over-rule one FAA.

 

[poadeleted20]

I'm also a fan of demonstrating power off recovery with pitch only -- despite the FAA's insistence on simultaneous power and pitch.

For those unfamiliar, the PTS section under discussion is:

C. TASK: POWER-ON STALLS (ASEL and ASES)

REFERENCES: FAA-H-8083-3, AC 61-67; POH/AFM.​

NOTE:​

​

​

​

​

In some high performance airplanes, the power setting may
have to be reduced below the practical test standards guideline power
setting to prevent excessively high pitch attitudes (greater than 30° nose
up).​

Objective.​

​

​

​

​

To determine that the applicant:
1. Exhibits knowledge of the elements related to power-on stalls.
2. Selects an entry altitude that allows the task to be completed no
lower than 1,500 feet (460 meters) AGL.
3. Establishes the takeoff or departure configuration. Sets power to
no less than 65 percent available power.
4. Transitions smoothly from the takeoff or departure attitude to a
pitch attitude that will induce a stall.
5. Maintains a specified heading ±5°, in straight flight; maintains a
specified angle of bank, not to exceed a 20°, ±10°, in turning
flight, while inducing the stall.
6. Recognizes and recovers promptly as the stall occurs by
simultaneously reducing the angle of attack, increasing power to
maximum allowable, and leveling the wings to return to a straightand-
level flight attitude, with a minimum loss of altitude​

appropriate for the airplane.

I think the FAA might want to consider a rewrite of that section to develop a more appropriate recovery technique for a Task which simulates a full-power stall entry.

 

[Dan Thomas]

I seem to recall hearing that the #1 cause of engine failure was insufficient fuel. That's a really stupid reason to have to ditch your plane.

That's number two. Carb ice is number one, unless you're talking fuel injection.

Dan

 

[Dan Thomas]

Funny, in the Dakota at 10,000 a power on stall is still a tail-sitter...

As it should be. Stall is dependent on angle of attack, not true airspeed. The true AS will be higher at stall at altitude, while the indicated AS and AoA will be the same.

Dan

 

[Ted]

That's number two. Carb ice is number one, unless you're talking fuel injection.

So what would #1 be overall, then per NTSB reports?

 

[Dan Thomas]

So what would #1 be overall, then per NTSB reports?

No idea. What's the ratio of carbed to injected engines? I think the carbureted engines would outnumber injected by a wide margin, and they're often flown by students or very occasional pilots who might not recognize the symptoms soon enough. I once did a search for carb ice on the AOPA accident database and it showed up with distressing frequency. The investigators can't usually name it as a certainty because the evidence (ice) is gone when they get there, so they'll say that the conditions were conducive to icing.

Dan

 

[Graueradler]

Did it encourage you to look up the performance tables before takeoff??

No - 7500 ft runway, 70 ft MSL - but it did encourage me to change my summertime take off practice to a notch of flaps and a Vx climb until clear of the field. We could have made a few new friends waving to people on the elevated roadway (I-110) SW of KBTR

Overhauled engine, 10 more horsepower, modified proptips, and VGs did a lot for take off and climb performance.

 

[gismo]

As it should be. Stall is dependent on angle of attack, not true airspeed. The true AS will be higher at stall at altitude, while the indicated AS and AoA will be the same.

Dan

But with a NA piston single the deck angle (which is far more obvious to most pilots than AoA) will be significantly lower at the onset of a full power stall at high DA with a full load than it will be at lower weights and lower DA.

 

[John Baker]

After having the engine modified a little on my Piper Warrior with a new Schneider racing cam with double valve springs, a Roots blower, supercharger, fuel injection and turbo charged, with a new five blade prop, I have found that I don't have to worry about no stinking stalls.

John

 

[dmccormack]

After having the engine modified a little on my Piper Warrior with a new Schneider racing cam with double valve springs, a Roots blower, supercharger, fuel injection and turbo charged, with a new five blade prop, I have found that I don't have to worry about no stinking stalls.

John

Pull the mixture then try it.

 

[EdFred]

#1. Given enough time, gravity is always going to win.

#2. Frederick's Law. Based on Godwin's law, the longer a thread continues the probability that someone will mention their time and experience approaches one. This usually occurs when the person mentioning said experience finds themselves losing the argument, or can no longer save face.

#3. No matter what plane you fly or own, you always want 20% better performance.

 

[dmccormack]

#1. Given enough time, gravity is always going to win.

#2. Frederick's Law. Based on Godwin's law, the longer a thread continues the probability that someone will mention their time and experience approaches one. This usually occurs when the person mentioning said experience finds themselves losing the argument, or can no longer save face.

#3. No matter what plane you fly or own, you always want 20% better performance.

After 250 hours this past year, I disagree with point #4.

 

[Arbiter419]

After 250 hours this past year, I disagree with point #4.

...#4?

Am I missing something?