32 votes

Why aren't takeoff flaps used all the way up to cruise altitude?

The image below from this answer shows characteristics of airfoils with flaps. As you rightfully concluded, lift ($C_{L_{max}}$) goes up with the deployment of flaps, but the drag also goes up and ...
ROIMaison's user avatar
  • 7,157
19 votes

Why aren't takeoff flaps used all the way up to cruise altitude?

This is a good question, and I don't feel the other answers get at the essential part which is: Is it optimal to climb with the flaps deployed? As with any optimal question, the answer relies on what ...
Kenn Sebesta's user avatar
  • 5,132
15 votes

Why do we calculate 25% more of TODR?

This is called a "safety factor", and I was actually taught to use 1.33! When you look at the POH or AFM the numbers and charts they present for performance figures were invariably ...
Jamiec's user avatar
  • 33k
14 votes

During an engine failure in Diamond DA-40, should the prop lever be at fine pitch or coarse pitch?

If your engine fails in a DA-40, you've lost oil pressure, so there likely isn't enough to push the blade to the coarse position. A DA-40 doesn't have an accumulator like a Seminole, for example. So ...
Ryan Mortensen's user avatar
12 votes
Accepted

What is this hole at the bottom of the DA40NG body?

That is a fuel sump drain valve. Water is heavier than fuel, so it sinks to the bottom of the tank. The sump drain valve is at the bottom of the tank so any water in the tank can be drained using the ...
GdD's user avatar
  • 54k
12 votes
Accepted

Where exactly is the engine compartment, remarked in yellow?

The engine compartment is the entire area between the firewall and the propeller, which is normally covered by the engine cowling. The alternate air valve opens to allow engine intake air to bypass ...
Mike Sowsun's user avatar
  • 37.8k
8 votes

What is considered "high altitude"?

It seems I've asked a question that has no answer. From the explanation below provided by a Diamond Aircraft representative, it is clarified that the intent of the AFM's caution is not to always run ...
hemp's user avatar
  • 579
8 votes
Accepted

How does the DA 40 NG automatically control the mixture, pitch and power by just providing one throttle?

According to Diamonds website the NG engine is a: Austro Engine AE 300 turbocharged common-rail injected 2.0 liter diesel engine with 168 hp and EECU single lever control system The prop is a: ...
Dean F.'s user avatar
  • 16.5k
7 votes

Why aren't takeoff flaps used all the way up to cruise altitude?

Because it would not be efficient. Flaps increase drag (and lift), so you would burn more fuel climbing to cruise altitude with flaps extended compared to if if you retract them.
60levelchange's user avatar
7 votes
Accepted

What does flight ID mean here in the picture? It stated in brackets for Performance

Since you tagged diamond-da40, I assume this is about the G1000 avionics as installed in the DA40. The manual for that G1000 unit is available on the Garmin website. According to the manual, the ...
Bianfable's user avatar
  • 55.9k
6 votes

Where exactly is the engine compartment, remarked in yellow?

They’re talking about the space inside of the engine cowling. In other words that valve can be set to feed ambient air into the turbo from an air scoop on the outside of the engine cowl. In the case ...
Romeo_4808N's user avatar
  • 73.7k
6 votes
Accepted

What is the function of the pipe referred to as "Venting Pipe" in the picture and how is it different from the exhaust pipe?

The “venting pipe” vents engine crankcase gases outside the aircraft. In the service manual it is called the “drain collector”.
Mike Sowsun's user avatar
  • 37.8k
5 votes
Accepted

Does a diesel piston engine's power decrease more slowly with altitude than with an AVGAS engine?

Welcome to the community! Because the Austro Engine AE-300 is a diesel engine,(JetA/Kerosene and Diesel are very similar) it is equipped with a turbocharger. Turbochargers compress the engine's intake ...
JetCityMatt's user avatar
  • 1,125
5 votes

What are these things on the horizontal stabilizer on a Diamond DA40?

As explained in a related post: The canted tips of the original DA42 are working like an anhedral and create a compensating positive rolling moment for the vertical tail's negative sideslip-induced ...
Peter Kämpf's user avatar
5 votes

Why do the Diamond DA-42 and DA-62 have a minimum fuel temperature requirement?

From the DA-42 TDI Approved Flight Manual: Fuel filter is not heated and can clog if the Diesel fuel flocculates. Jet fuel does not pose same limitations.
Cpt Reynolds's user avatar
  • 4,807
5 votes

What is the name and purpose of this part on the flap at the DA40?

These are hinges, pivot points for the flaps, and some of them also probably contain the extension mechanism. The flaps on the DA-40 are slotted flaps, which are similar to plain and split flaps in ...
GdD's user avatar
  • 54k
5 votes

What is the name and purpose of this part on the flap at the DA40?

It is an actuator fairing. It covers the flap actuator so to minimize the drag created by it. An actuator directly exposed to the airflow would create more drag, increasing fuel consumption and ...
Federico's user avatar
  • 32.6k
5 votes
Accepted

Is the attitude gyro (artificial horizon) equipment on our DA40NG aircraft powered by electricity?

That attitude gyro is electric, and having a standalone emergency battery power supply, is your last resort to get to VFR conditions if you have a primary flight display failure and/or total ...
John K's user avatar
  • 131k
4 votes
Accepted

What is the name and purpose of this part on the flap at the DA40?

Given the position on the wing, that appears to be the linkage for the aileron control rod which actuates the ailerons, not flaps. The outboard flap hinge can be seen to the left of that. With the ...
Romeo_4808N's user avatar
  • 73.7k
4 votes

How does the DA 40 NG automatically control the mixture, pitch and power by just providing one throttle?

Aside from the fact that the engine is computer controlled... the reason you don't have mixture control is Diesels don't use that. Gas engines need to breathe a stochiometric mix of air and fuel, ...
Harper - Reinstate Monica's user avatar
4 votes

Why does RPM increase when you lean the mixture in constant speed propeller engine?

It's because at the power setting you are using for those checks, the prop is still "off the governor"; the blades are still at their fine pitch stops, because the governor is calling for ...
John K's user avatar
  • 131k
3 votes

Why do we turn on fuel pump before descent in Diamond DA40?

AFAIK, every low-wing plane requires the boost pump to be on during takeoff, climb, descent and landing. This is a safety measure. When you are flying low and slow, the consequences of the engine-...
StephenS's user avatar
  • 27.7k
3 votes

What is vapor lock?

what causes vapor lock? Fuel pumps found on GA planes are designed to pump liquid fuel. They won’t pump fuel vapor. Vapor lock occurs when fuel in the supply plumbing gets heated above the fuel’s ...
Skip Miller's user avatar
  • 10.3k
3 votes
Accepted

Is right rudder always needed during go-around/touch and go with a Diamond DA-40?

"More right rudder" is like a Flight Instructor's mantra, for most all small single engine planes where the propellor spins clockwise from the pilot's viewpoint, and right rudder is needed when engine ...
CrossRoads's user avatar
  • 8,795
3 votes

What does flight ID mean here in the picture? It stated in brackets for Performance

The callsign being used for this flight, which will then feed from the FMS into the Mode-S transponder. This is how FlightRadar24 tags your flight.
RAC's user avatar
  • 4,616
3 votes

Why DA40 got some aircraft variants with gust lock on the left seat and some on the right seat?

The AFM indicates that the gust lock must be wrapped once around the stick and the rod engaged with the pedals fully slid back: (source) it does not specify which side it is to be mounted on although ...
Dave's user avatar
  • 101k
2 votes

How does the DA 40 NG automatically control the mixture, pitch and power by just providing one throttle?

As stated above in the last answer, it’s turbodiesel powered. Like the DA-42 and DA-62, the engine is basically power by wire, using a primary and secondary Engine Control Unit (ECU) computers, each ...
Romeo_4808N's user avatar
  • 73.7k
2 votes

How does the DA 40 NG automatically control the mixture, pitch and power by just providing one throttle?

Other answers concentrated more on the 'mixture' and FADEC side of things. I'll show what it does with the prop speed. This is actually simpler and is explained right in the flight manual (p. 7-25). ...
Zeus's user avatar
  • 9,063
2 votes
Accepted

DA40 fuselage static ports / G1000 not in AFM

I found the answer by further reading the AFM. On DA40's with an auto pilot installed, optional static ports may be added to the fuselage.
aaronstran's user avatar
2 votes

Why do we turn on fuel pump before descent in Diamond DA40?

The previous answer stating that it is standard procedure on a low-wing aircraft to turn the electric/aux fuel pump on for takeoff for safety and to turn it on for descent to prevent vapor lock during ...
JetCityMatt's user avatar
  • 1,125

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