Learning new plane: Diamond DA-40 w/G1000

[Jaybird180]

Let me start by saying this thing is Saaaaaweeeeet!

Very responsive and smooth. Excellent visibility...This plane may just be enough to get my wife to sit still long enought during our upcoming XC to complete the trip in a single hop.

I have a couple questions that I've asked the CFI, but that's one man's opinion. I'd like to get others. Mention that this is also my first venture into the low-wing world.

These questions are for my knowledge of the fuel system ONLY!

This particular aircraft has 2 fuel probes for the fuel meter. In a low fuel situation, slipping on final, which tank should I draw fuel from (up or down wing)?

Secondly, if I needed to go to legal fuel minimums (30 min Day VFR), how much can I trust the accuracy of the G1000 fuel gauges?

 

[TMetzinger]

You should not trust the gauges. You CAN trust the totalizer, though, IF you give it a known good quantity of fuel to begin with.

What I do is:

Find out how much fuel is in the tanks, either by topping it off slowly, or by using the handy-dandy Diamond sight gauge.
Put that much fuel into the G1000 on the Engine/System/Add fuel function.
Subtract two or three gallons "for the wife and kids".

Then if I'm not on final with an hour of fuel remaining, I'm diverting to the nearest airport with fuel. Period.

As for slipping, there is ONE fuel pickup per tank, at the wing root. Therefore you want to slip in such a way that fuel is collecting at the root of the wing you are draining from. If you tilt the airplane, then drain off the higher wing.

 

[Jaybird180]

You should not trust the gauges. You CAN trust the totalizer, though, IF you give it a known good quantity of fuel to begin with.

Is that the thing that counts down?

Find out how much fuel is in the tanks, either by topping it off slowly, or by using the handy-dandy Diamond sight gauge.
Put that much fuel into the G1000 on the Engine/System/Add fuel function.
Subtract two or three gallons "for the wife and kids".

Then if I'm not on final with an hour of fuel remaining, I'm diverting to the nearest airport with fuel. Period.

As for slipping, there is ONE fuel pickup per tank, at the wing root. Therefore you want to slip in such a way that fuel is collecting at the root of the wing you are draining from. If you tilt the airplane, then drain off the higher wing.

I haven't been introduced to the fuel sight gauge yet. Have only had one flight and been reviewing the documentation (thanks BTW).

So when you say subtract 2-3 gals, do you mean to say that you tell the G1000 that you have 38 or 39 gals on board when you're really full? And then you still keep your 1hr reserve based on what the totalizer is reading? Err on the side of caution can't be bad.

Thank you for answering that question on slipping. I like slips.

 

[EppyGA]

Tim's trying to say that most pilots are never knowingly going to run the tanks down to a 1/2 hour. Doesn't take much misjudgment to be flying along and the fan stops turning. BTW, what's a Skyhawk type rating?

 

[Mtns2Skies]

I like slips.

Be careful in the shower and tub.

 

[TMetzinger]

Is that the thing that counts down?



I haven't been introduced to the fuel sight gauge yet. Have only had one flight and been reviewing the documentation (thanks BTW).

So when you say subtract 2-3 gals, do you mean to say that you tell the G1000 that you have 38 or 39 gals on board when you're really full? And then you still keep your 1hr reserve based on what the totalizer is reading? Err on the side of caution can't be bad.

Thank you for answering that question on slipping. I like slips.

Yes, the totalizer is the device that measures the fuel flow to the engine, and constantly decrements the amount of fuel you have remaining.

Yep, I put in 40 gal, tell the system I have 38, and then when the totalizer shows 1 hour (10 gal or so) remaining I'm either on the ground, on final, or heading for a nearby fuel stop. If yours has long-range tanks, I'd put in whatever full fuel minus 2 gallons is. The two gallons is to ensure that if I don't have exactly full fuel in the airplane, at least I have MORE fuel than I told the totalizer.

Effectively I give myself 2:45 - 3:00 legs in the airplane. Keeps me from looking really stupid by running out of gas, and lets me stretch and pump bilges too. Our rental agreement requires planning for one hour reserve, and landing with a min of one hour in the tanks. Sometimes that gets pushed a little bit, but not by much.

Once I diverted at the hour mark to an airport 20 min away, and had about 38 min of fuel remaining on landing. I was not as comfy as I like to be by the time I landed.

I've promised myself that no matter what other stupid things I may do by accident in an airplane, running out of fuel isn't going to be one of them.

 

[HPNPilot1200]

You should not trust the gauges. You CAN trust the totalizer, though, IF you give it a known good quantity of fuel to begin with.

My emphasis in bold.

This is a very important point. Garbage in, garbage out. The known quantity has to be set everytime you refuel. In the SR20, we have soft keys for FULL, TABS, +1, and -1 increments which must be set on MFD initialization.

 

[TMetzinger]

My emphasis in bold.

This is a very important point. Garbage in, garbage out. The known quantity has to be set everytime you refuel. In the SR20, we have soft keys for FULL, TABS, +1, and -1 increments which must be set on MFD initialization.

Diamond and Cessna are similar, usually the pre-set quantities are for full tanks, tabs if equipped, and then +/- quantities.

See my post (in a few min) about data logging.

 

[Jaybird180]

BTW, what's a Skyhawk type rating?

I got it when I got my yellow belt:wink2:

 

[ElliotR]

I second all of Tim's excellent posts ITT. in my experience (with he 50 gal. Tanks) the fuel totalizer is very very accurate.

I also have checking and setting it on my "after-start" checklist.

 

[AggieMike88]

Let me start by saying this thing is Saaaaaweeeeet!

Very responsive and smooth. Excellent visibility...This plane may just be enough to get my wife to sit still long enought during our upcoming XC to complete the trip in a single hop.

Just a comment about the aircraft....

Be careful... that thing is addicting!

I did my training in the DA40's younger brother, the DA20. And it for sure is one ride I always enjoy flying. Performance and visibility get you real spoiled when you switch over to other aircraft.

Great aircraft to reinforce importance of correct approach/landing speeds. Come in faster than needed and that glider wing will carry you quite a ways in ground effect.

 

[Wingsofglass]

I have about 500 hours in my DA40. Why anyone would fly it to VFR min fuel is beyond me. I flew it for 710nm and just shy of 5 hours a few weeks ago and still landed with 13 gallons in the tanks (I have 50 gal tanks).

The fuel totalizer is more accurate than the tank gauges, although my tank gauges seem pretty accurate. I fill to the top, reset the fuel on the engine page of the MFD and then subtract 2, just like mentioned above. The G1000 will show a range ring on the MFD (at least my version does) displaying how far you can go with remaining fuel. Keep in mind this is driven off the totalizer, which is something set by the pilot so it's only as accurate as what is entered.

 

[flyingcheesehead]

Let me start by saying this thing is Saaaaaweeeeet!

Welcome to the DA40 addicts club.

Very responsive and smooth. Excellent visibility...This plane may just be enough to get my wife to sit still long enought during our upcoming XC to complete the trip in a single hop.

Just make sure she doesn't wear a skirt.

I have a couple questions that I've asked the CFI, but that's one man's opinion. I'd like to get others.

Hey, that's what we're here for. And I'm happy to share anything I know about the DA40.

These questions are for my knowledge of the fuel system ONLY!

This particular aircraft has 2 fuel probes for the fuel meter. In a low fuel situation, slipping on final, which tank should I draw fuel from (up or down wing)?

Generally on any small airplane's wing tanks, your intake will be on the inboard edge of the tank somewhere. Why? Dihedral will push the fuel that way in level flight. So, draw from a tank that you'll be pushing the fuel towards the wing root with whatever maneuvering you'll do. In a slip, that'll be the high wing.

Secondly, if I needed to go to legal fuel minimums (30 min Day VFR), how much can I trust the accuracy of the G1000 fuel gauges?

IME, they're pretty good. However, that's on my airplane. Yours may vary. As far as I've been comfortable drawing the tanks down (my personal minimum for fuel is 1 hour, so pretty close to that), both the gauges and the totalizer were about a gallon off after burning 40 of the 50 gallons available on the DA40 I fly. (Aside: Does the one you're flying have the standard 40-gal or long-range 50-gal tanks?) They also both erred on the conservative side - The gauges showed that I had slightly less fuel than I did, and the totalizer showed that I had burned slightly more, but like I said they were both about 1 gallon off after burning 40 out of 50 gallons.

However, this is something you need to check on the particular airplane you fly (and this goes for any aircraft type, not just the DA40). Every one of them will be different. When you go on a longer XC flight, start topped off, pay attention to the gauges, burn 50%-60% of your usable fuel (assuming that this still leaves you with a good reserve - They're rare, but some airplanes can only go a couple of hours to dry tanks), stop for fuel, make sure it's topped off again (and that also means that you need to turn the fuel selector to OFF on Cessnas and other "Both" birds), see how much you add and how it compares with what your gauges and totalizer said. If the numbers are all in agreement, go ahead and do a leg where you burn down closer to your reserves, lather, rinse, repeat. Pretty soon you'll have a good idea of how the fuel instrumentation works in that airplane.

You should not trust the gauges. You CAN trust the totalizer, though, IF you give it a known good quantity of fuel to begin with.

Well, mostly. Even totalizers aren't perfect, and need to be tested as I outlined above.

Find out how much fuel is in the tanks, either by topping it off slowly, or by using the handy-dandy Diamond sight gauge.

I've actually found the Diamond sight gauge to be less than ideal due to bubbles and such getting trapped in the opaque hose occasionally, which results in the sight gauge showing that there's more fuel than there really is. Tread with caution.

Put that much fuel into the G1000 on the Engine/System/Add fuel function.

You must have an older software rev. On 0321.22 (actually I think it was .19 and newer) there is no more "System" page, and the fuel softkeys are right on the Engine page on the MFD (lower right.)

Is that the thing that counts down?

Yup.

I haven't been introduced to the fuel sight gauge yet. Have only had one flight and been reviewing the documentation (thanks BTW).

Try using it a few times when there's a known quantity of fuel in the tanks so that you can see its quirks (see above).

So when you say subtract 2-3 gals, do you mean to say that you tell the G1000 that you have 38 or 39 gals on board when you're really full? And then you still keep your 1hr reserve based on what the totalizer is reading? Err on the side of caution can't be bad.

Well... It's certainly better than doing things the other way around! However, there was an old John Deakin article on AvWeb where he suggested being more accurate about such things, so that when the poop hits the prop you'll have a better idea of what fields you're capable of diverting to and the like. I don't think that Tim's method is "wrong" or that Deakin's method is "right" but it's something to think about and consider. Luckily, for VFR flying in a non-complex airplane there aren't a whole lot of things that you'll want to stay in the air for when the situation goes bad (unless, of course, you do end up in IMC). But it's still something to think about for later training and ratings.

Yes, the totalizer is the device that measures the fuel flow to the engine, and constantly decrements the amount of fuel you have remaining.

Caveat: Someone can correct me if I'm wrong, but I'm pretty sure that the totalizer on the DA40 is not actually measuring fuel flow, it's measuring fuel pressure and mathematically converting that to flow which probably isn't the most accurate method of measurement (despite my good results). Earlier DA40's showed a fuel pressure gauge as opposed to the fuel flow gauge that's present in newer revisions.

I've promised myself that no matter what other stupid things I may do by accident in an airplane, running out of fuel isn't going to be one of them.

Amen. And with the way the DA40 sips fuel, there is no excuse for running out.

I second all of Tim's excellent posts ITT. in my experience (with he 50 gal. Tanks) the fuel totalizer is very very accurate.

Well, that makes at least two of us. (Long range tanks here too.)

Just a comment about the aircraft....

Be careful... that thing is addicting!

Very. It has its quirks due to tradeoffs in the design decisions that were made (most of which I agree with!) but overall it is a VERY enjoyable airplane.

I did my training in the DA40's younger brother, the DA20.

Great aircraft to reinforce importance of correct approach/landing speeds. Come in faster than needed and that glider wing will carry you quite a ways in ground effect.

True, but I was actually surprised at how well the DA40 slows down once you add flaps. I think that's mostly due to the inboard 2-2.5 feet of each flap acting as a split flap. I'm not sure if the DA20 is that way or not. On the DA40, where the rubber seal is that separates the separable part of the wing from the inboard couple of feet that is permanently part of the fuselage, the flap doesn't end, it goes a couple feet farther inboard and the fuselage-attached piece of wing has a top skin that covers the full chord including the flap. So, 42 degrees ("Landing") flaps, with a wide span and part of them acting as split flaps, makes an amazing speed brake.

For comparison, I like to practice max-effort fast ILS approaches to be nice to ATC when there's a jet following me in. In the 182, I can fly the ILS at 140 knots, cut the power at about 325 AGL and still slow it down in time to touch down in the TDZ. In the DA40, I can fly the ILS at 145 knots, but I have to pull the power at around 600 AGL to get it slowed down in time to not float forever.

Man, I had a great approach in the DA40 last night - right down the PAPI glidepath, smooth slowdown from cruise to final approach speed, smooth touchdown about 400 feet down the runway... But I forgot to put a data card in to capture exactly how I did it. I know I did my normal pull-to-20" MP as I got down to about 2500, pulled again when I got closer but instead of my normal midpoint setting I kind of pulled it a couple of times as I descended and slowed, and I think I ended up at around 12" on short final, but I guess I'll never know for sure... Doh! I guess I need to go practice again.

I have about 500 hours in my DA40. Why anyone would fly it to VFR min fuel is beyond me. I flew it for 710nm and just shy of 5 hours a few weeks ago and still landed with 13 gallons in the tanks (I have 50 gal tanks).

I sure wouldn't fly it down to VFR min fuel, but you don't need ridiculously long legs to get there - One "weakness" of the DA40 (in quotes because it's mainly a weakness compared to the 182 that I also fly) is its useful load, and especially with the long range tanks you can make the tradeoff between fuel and payload quite nicely, as long as you don't have the plane topped off (it's almost impossible to de-fuel a DA40 more than about 8 gallons). The flight whose data I posted on the other thread is a good example of that. We did end up diverting on the way back because we weren't going to make it all the way back with full fuel.

 

[Jaybird180]

The fuel totalizer is more accurate than the tank gauges, although my tank gauges seem pretty accurate. I fill to the top, reset the fuel on the engine page of the MFD and then subtract 2, just like mentioned above. The G1000 will show a range ring on the MFD (at least my version does) displaying how far you can go with remaining fuel. Keep in mind this is driven off the totalizer, which is something set by the pilot so it's only as accurate as what is entered.

2nd flight scheduled this evening so...getting some good info on this thread.

Do you input -1 gal per tank or is it not tank specific?

Lean Find: is that ROP or LOP?

Cheese- Lots of good stuff there.

BTW all- The plane I'm using has standard (41 gals usable) tanks.

 

[Sac Arrow]

I've accumulated about ten hours or so of time in a DA40 and I find them very addictive as well. The only two major gripes I had was 1) could have used more rudder authority (apparently fixed in newer models), and 2) smallish fuel tanks (fixed with 50 gallon long range tanks.)

Definately on my radar should I choose to buy a plane again.

 

[Jaybird180]

Definately on my radar should I choose to buy a plane again.

I feel guilty, but I'm looking at the DA-50

 

[flyingcheesehead]

Do you input -1 gal per tank or is it not tank specific?

The totalizer is not tank specific.

Lean Find: is that ROP or LOP?

Sounds like you've used a JPI before? The Lean function on the G1000 is not geared toward either ROP or LOP, it'll work for both. On the engine page, when you hit "Lean" it'll add a line underneath the EGT's that says "∆Peak 0" and you just lean veeerrrrrrrryyyyyyy ssssslllllloooooowwwwwlllyyyy and watch the EGT's rise. When the first cylinder peaks, there'll be a blue line added to its EGT gauge marking the peak and it'll say "1st" above it. The ∆Peak will begin showing negative numbers as that EGT goes down. If you choose to run ROP, just richen it up until it hits peak and if you're looking for 50 ROP for example you'll just wait until it says "∆Peak -50" (or so) at the bottom. You'll end up needing to give yourself a 5-degree tolerance either way, it's very difficult to hit it right on the degree, and there's about a 2-3 second lag from when you move the mixture knob until the EGT's change.

If you want to run it LOP, after that first cylinder peaks just keep leaning slowly and each cylinder in turn will have the blue bar added to its EGT gauge where it peaks. The last one will be marked "Last" and the ∆Peak number will now be the difference from the last cylinder's peak. So, if you want to run 25 LOP, just keep going until it says "∆Peak -25" or so.

It's much easier than JPI's way (where you have to specifically set it to ROP or LOP in advance), and IME works better - The G1000 eliminates the false peaks that require "pre-leaning" on the JPI. On the DA40, you'll end up with a fuel flow in the neighborhood of 10-11 gph ROP or 7-8 gallons LOP.

BTW all- The plane I'm using has standard (41 gals usable) tanks.

Careful - 41 total, 40 usable on the standard tanks. That's still enough to get you a good solid 400nm away with an hour reserve running ROP.

IIRC your "blank" area on the fuel gauges is at the top of the tanks, where you can see the fuel anyway, and the gauges read from 17 gal per side down.

BTW, do you have a DA40 POH/AFM yet? If not, it's available in electronic form (and kudos to Diamond for that! ).

Current revision is here. Thanks to the quirks of certification, this manual does NOT cover the G1000. For the G1000 manuals (for the current software rev, 0321.22 - Check yours when you boot it up), go here. The AFM supplement, which includes some checklists more specific to the G1000, is different depending on which autopilot you have and is the smallest of the three manuals. It's also required to be in the airplane, and in turn requires the middle child of the manuals, the Cockpit Reference Guide, to be in the airplane as well. Finally, the Pilot's Guide will give you every little stinking detail you ever (or never!) wanted to know about the G1000.

I feel guilty, but I'm looking at the DA-50

The Magnum, or the SuperStar? The Magnum is diesel and will be interesting, but the SuperStar is going to be one hell of an airplane. 350hp, turbo, pressurized. 52-inch-wide cabin (that'd be 6 inches wider than the 182!) and a massive baggage area. And did I mention, pressurized? That alone must have Cirrus shaking in their boots...

 

[Jaybird180]

I have no JPI experience other than reading Deakin articles.

The fuel flow you mentioned above, is this the reason why the performance tables in the .pdf manual I have provides 2 fuel flow numbers given the same MP and RPM (scratching head)?

 

[AggieMike88]

I feel guilty, but I'm looking at the DA-50

The school I trained at also has a DA42 Twin Star. I don't know any performance info on it, but as a light twin, it sure looks much sexier than the Senacas its parked next to.

 

[flyingcheesehead]

The fuel flow you mentioned above, is this the reason why the performance tables in the .pdf manual I have provides 2 fuel flow numbers given the same MP and RPM (scratching head)?

Yes. But those are even different numbers than I gave. (Doh!)

Generally, "Best Power" will be 100º ROP. The "ROP" numbers I gave are for about 50º ROP. The "Best Economy" numbers are probably for right at peak, and the "LOP" numbers I gave are more like 25º LOP. But you can see that they all fit together just about right. (From richest to leanest, Best Power, ROP, Best Economy, LOP)

Remember that all three levers (throttle, prop, mixture) affect power. The throttle is controlling the air pressure available to the cylinders - When you pull it back, the pressure of the air that enters the cylinder on the intake stroke (and thus the mass of oxygen available to burn) will be lower. The prop lever, by controlling the RPM, affects the number of burn cycles available. When the RPM is lowered, there will be fewer power strokes per minute (and, of course, fewer times that air is drawn into the cylinders). Finally, the mixture knob - When you're at the Best Power setting, you have the optimum fuel/air ratio to achieve the most forceful burn inside the cylinder. As you lean, you'll develop less power - If you do not change the MP or RPM, leaning from Best Power to Best Economy will slow you down. At Best Economy, you should have the perfect stoichiometric ratio of fuel to air, so you'll get the most complete burn but slightly less power. As you continue leaning lean of peak/Best Economy, you're beginning to remove fuel, which means less power still, but excellent efficiency.

 

[flyingcheesehead]

The school I trained at also has a DA42 Twin Star. I don't know any performance info on it, but as a light twin, it sure looks much sexier than the Senacas its parked next to.

Yup. Sadly, they don't perform all that well, though their performance is roughly comparable to those Senecas. Pretty much 160-165 for both on a good day.

The TwinStar has a few nice things about it, though... One is the stout landing gear. Get under there and look at it sometime - It looks like it came off a bizjet or something. But, in the TwinStar Vlo=Vle=Vne=194 KIAS. So, the TwinStar's gear makes a GREAT speed brake because you can throw it out there any time you want to.

They did make mention a few months ago, when talking about one of the Austro engines, that there was going to be a "next-generation twin" coming out. The logical extension of their other work leads me to believe that it'll be a "DA52" that combines the best parts of the DA42 with the high altitude capability, pressurization, and speed of the DA50. If they can just make it with a pax door that doesn't require climbing on the wing, six seats, and keep the good things they have going with the rest of their line, I think they'll have a real winner on their hands - Finally, a modern replacement for the P-Baron! But they'll have to keep the price relatively low as well, or people will simply go for the small jets or the single-engine turboprops instead.

 

[xaminmo]

FWIW, the DA40 will sputter a little under 7gal on a side in turbulent air, or when banking. The aux pump is your friend then, as it is when the engine is hot and you're trying to start for a midday flight.

The totalizer is good. Fuel flow is good. The gauges on the DA40 are actually pretty good, but the totalizer is good so you can adjust your flow and keep tabs more accurately.

The DA42 is very glidery like the DA40 is, so it beats out the seneca in that regard. Rumor had it that a few years ago, the DA42 out in Denton or one of its relatives had a computer failure and shut down both engines in flight. They landed on-field 12 miles away.

 

[Jaybird180]

I'd heard somewhere that it's good to keep 15 gals as minimum. So much for useful fuel, huh?

 

[Henning]

Yes, the totalizer is the device that measures the fuel flow to the engine, and constantly decrements the amount of fuel you have remaining.

Yep, I put in 40 gal, tell the system I have 38, and then when the totalizer shows 1 hour (10 gal or so) remaining I'm either on the ground, on final, or heading for a nearby fuel stop. If yours has long-range tanks, I'd put in whatever full fuel minus 2 gallons is. The two gallons is to ensure that if I don't have exactly full fuel in the airplane, at least I have MORE fuel than I told the totalizer.

LOL, to me this is the same as people who set the clock 10 minutes fast, it doesn't make sense, and in a rental plane it is just plane wrong. It can cause someone in a bind to risk setting down off airport when they really had enough fuel to make a runway. This is one of the ways an outside party can make one of your six mistakes for you and you don't even know it.

In a rental/community use plane, always enter accurate figures into the fuel computer because not everybody knows that that extra 15 minutes/33 miles (or greater if you pull back some) are available to them. That's not good. People spend money on fuel totalizers so they know exactly how much fuel they have.

 

[xaminmo]

I'd heard somewhere that it's good to keep 15 gals as minimum. So much for useful fuel, huh?

That sounds about right. That would be 7.5 per side. It's happy with aux pump on down to 5 on a side. Below that, you want to be straight and level. You get an alarm at 3 gallons on either side. If you knew for certain you'd be making left turns, you could burn the left tank dry at altitude.

The risk is partially made up for by the excellent glide. Pull the prop all the way back and it helps a little. If you can get the prop to top, it's even better, but you'd better be really light or you'll stall it in the process.

If it's got a G1000, there's a pretty, green, glide ring for you on the map, but it's almost such that, at light load, if you were out of fuel, you could pretty much glide to anything on the ground you can see.

LOL, to me this is the same as people who set the clock 10 minutes fast, it doesn't make sense, and in a rental plane it is just plane wrong. It can cause someone in a bind to risk setting down off airport when they really had enough fuel to make a runway. This is one of the ways an outside party can make one of your six mistakes for you and you don't even know it.

In a rental/community use plane, always enter accurate figures into the fuel computer because not everybody knows that that extra 15 minutes/33 miles (or greater if you pull back some) are available to them. That's not good. People spend money on fuel totalizers so they know exactly how much fuel they have.

This ^^^^. Truly. The totalizer, and even the gauges, are very accurate in DA40s. Plus, it gives you an audible and visual alarm when you go below 3 gallons in a tank, and again for the other tank. There is no need to tinker with reality or cause some student to get confused and tell his DPE "yes, this plane has 38 gallons capacity!".

 

[Jaybird180]

What's normal oil consumption range?

 

[Wingsofglass]

I use about a quart every 25 hours.

 

[flyingcheesehead]

FWIW, the DA40 will sputter a little under 7gal on a side in turbulent air, or when banking. The aux pump is your friend then, as it is when the engine is hot and you're trying to start for a midday flight.

I'd heard somewhere that it's good to keep 15 gals as minimum. So much for useful fuel, huh?

Huh. I ran one tank down to ~3 gal and didn't have that problem.

I would imagine that it's similar to any other one-wing-at-a-time fuel system in that if you unport the fuel via uncoordinated flight of any variety, you're gonna get a sputter.

 

[TMetzinger]

LOL, to me this is the same as people who set the clock 10 minutes fast, it doesn't make sense, and in a rental plane it is just plane wrong. It can cause someone in a bind to risk setting down off airport when they really had enough fuel to make a runway. This is one of the ways an outside party can make one of your six mistakes for you and you don't even know it.

In a rental/community use plane, always enter accurate figures into the fuel computer because not everybody knows that that extra 15 minutes/33 miles (or greater if you pull back some) are available to them. That's not good. People spend money on fuel totalizers so they know exactly how much fuel they have.

In a shared airplane, measure your own fuel and set the totalizer to match your practices.

Oh, and don't fly to the point where two gallons really makes a difference. Since our rental agreement requires landing with one hour of fuel on board....

 

[Jaybird180]

Quick question guys: My CFI teaches to back off the power after verifying VSI, yet still prior to reaching pattern altitude. I intend to change this when I solo (or carry my family) to backing off the power only after reaching pattern altitude. So the question is, which is the better practice? Which gets me to pattern altitude faster, full power, full forward prop (2700 rpm) or 25"/2400 rpm?

 

[flyingcheesehead]

Quick question guys: My CFI teaches to back off the power after verifying VSI, yet still prior to reaching pattern altitude. I intend to change this when I solo (or carry my family) to backing off the power only after reaching pattern altitude. So the question is, which is the better practice? Which gets me to pattern altitude faster, full power, full forward prop (2700 rpm) or 25"/2400 rpm?

Full power, full forward will get you to pattern altitude faster.

I pull the prop back to 2500 at ~500 AGL, mostly to be nice to the airport neighbors.

He may have you backing off during pattern work because the DA40 will accelerate very quickly once you level off.

BTW, what do you mean by "verifying VSI?"

 

[Jaybird180]

What I should have said, is this is on normal climbout at 300' he asks me to goto 25"/2400 not pattern work. This is after verifiying that we're still climbing. Then after power change, flaps up, fuel pump-off, lights-off.

My question was if you thought this was premature to change configuration?

I understand the flaps (after obstacle clearance-that is) and I get the value of being nice to the engine, but the POH authorizes full power/2700 for short periods of time (takeoff and climbout) and emergencies.

 

[Gary F]

Quick question guys: My CFI teaches to back off the power after verifying VSI, yet still prior to reaching pattern altitude. I intend to change this when I solo (or carry my family) to backing off the power only after reaching pattern altitude. So the question is, which is the better practice? Which gets me to pattern altitude faster, full power, full forward prop (2700 rpm) or 25"/2400 rpm?

I assume that you are referring to the DA40 with Lycoming powerplant. Full power is better for climb. I believe that the reduction in rpm from 2700 to 2400 is more for noise abatement which is a big issue in Europe. The prop and engine are both rated for 2700. I usually reduce rpm after reaching 800 to 1000', on occasion higher if the extra altitude is necessary for safety.

 

[TMetzinger]

I don't see a problem with it, though I'd probably wait until a little bit higher. I usually don't do ANY power reductions until I'm at pattern altitude, then I nose over briefly to get a good look at what's been hidden behind the cowling before resuming the climb. For the DA-40 I climb out at 25"/2500RPM.

Where most people at my school mess up is when they level off at 1400 (to stay below the bravo airspace at 1500) and they accelerate past the Vfe for the flap setting. I try and teach that the flaps may come up at 600' AGL.

But you should fly the airplane the way your checkout instructor wants you to unless it violates some limitation in the AFM. You might ask why the power reduction is done that early - I'd be interested in hearing the answer.

 

[Jaybird180]

I don't see a problem with it, though I'd probably wait until a little bit higher. I usually don't do ANY power reductions until I'm at pattern altitude, then I nose over briefly to get a good look at what's been hidden behind the cowling before resuming the climb. For the DA-40 I climb out at 25"/2500RPM.

Where most people at my school mess up is when they level off at 1400 (to stay below the bravo airspace at 1500) and they accelerate past the Vfe for the flap setting. I try and teach that the flaps may come up at 600' AGL.

But you should fly the airplane the way your checkout instructor wants you to unless it violates some limitation in the AFM. You might ask why the power reduction is done that early - I'd be interested in hearing the answer.

I do everything he says, because I am THE STUDENT even when I disagree (provided it's not a safety or regulatory issue). I have on one occasion given a safety suggestion, which he accepted. But we do have our moments when we're not communicating because I don't see how what he's asking will get us to our prior established goal (like a botched pattern entry), yet I do it anyway because it's not a safety or regulatory issue.

 

[flyingcheesehead]

I do everything he says, because I am THE STUDENT even when I disagree (provided it's not a safety or regulatory issue). I have on one occasion given a safety suggestion, which he accepted. But we do have our moments when we're not communicating because I don't see how what he's asking will get us to our prior established goal (like a botched pattern entry), yet I do it anyway because it's not a safety or regulatory issue.

Ummm.... I would suggest that you not approach training as a simple "he's right because he's the instructor" situation. "Why?" is always an appropriate question, and he should always have an appropriate answer.

IMO, 300' is a bit low to be changing things. I know you're still not instrument rated, but with instrument flying you need to climb 400 feet before turning on course (unless there's an ODP), so I personally like to stay in that habit VFR as well. After the initial turn is completed, THEN start messing around with other things.

In the DA40, there are three things to be done shortly after takeoff: Fuel pump off, flaps up, and power reduction. (I prefer to leave the lights on until reaching cruise altitude so that other traffic in the airport area has a better chance of seeing me.) I don't always do them in the same order - The fuel pump, I turn off after I have enough altitude to make it back to a runway. I like to pull the prop back before flying over residential areas (no need to pull MP back on this engine, or many others). Flaps, I usually wait until terrain and other operational considerations allow for accelerating to a cruise climb of 90 knots or so (NOT the 73 knot "cruise climb" that's in the POH) because the plane really likes to sink when flaps are retracted otherwise, and I like to keep the engine cool.

 

[Jaybird180]

I'll have to revisit my climbing technique, but when I retract flaps I just get a surge of acceleration, no drop like in the 172s I used to fly.

 

[Jaybird180]

Oh, and...I ain't gonna do nuthin' stoopid jus' cuz he knows more not falling for that trap (I should have seen that comment coming).

 

[flyingcheesehead]

I'll have to revisit my climbing technique, but when I retract flaps I just get a surge of acceleration, no drop like in the 172s I used to fly.

Huh... I have to give it a noticeable pitch up during the retraction to not sink, though pretty much as soon as it's done retracting I'm back down to the initial pitch and accelerating.

Oh, and...I ain't gonna do nuthin' stoopid jus' cuz he knows more not falling for that trap (I should have seen that comment coming).

I'm not saying that in relation to stupid things, I'm saying that in relation to EVERYTHING you should ask why he wants you to do things a certain way. Otherwise, someday when another CFI tells you to do it a different way, how will you know which one is truly better/safer?

 

[xaminmo]

What's normal oil consumption range?

I like to say, anything less than the engine manual's max oil consumption.

Continental says (Lb./BHP/Hr. Max.) = (.006 X % Power) / 100, and I think oil weighs around 1.8 LBS per quart, but it varies by temperature, brand, viscosity, etc.

Lycoming says .006 x BHP x 4 ÷ 7.4 = Qt./Hr (which is .00324324... per HP per hour). On the DA40, that would be .5837 qt/hr as a limit.

In practice, I found it to be around .2 per hour on mid-time, school planes. Remember, rentals are usually hobbs, but oil consumption is based on tach.