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A "straight and level angle of attack" is an example of something that doesn't actually exist. With enough power you can fly straight and level at any angle of attack from VNE through to stall speed. I'm not sure that your understanding of angle of attack is correct. What do you think the angle of attack will be at 60 knots cruise? 60 knots climb? 60 knots glide? Pulling 4G at 120 knots 3/4 of the way around a loop? All will be the same angle of attack. What do you think your bubble AOA indicator will show? Descent doesn't mean lift is insufficient. Lift doesn't change significantly in a climb, descent or straight and level. (Ignoring the vertical components of thrust and drag, which actually reduce lift required for both climb and descent). Climb and descent are a result of power settings. Descent means that you have insufficient power to overcome drag, climb means you have more power than drag. They are not an increase or decrease in lift.

That's the point I think. APenNameAndThatA was listing things that OME has posted that are not actually true. I'm sorry if OME feels picked on. What do you suggest should be done when incorrect information is posted to the Student Pilot area? I have a growing suspicion that OME is trolling us with deliberately false theories. If so the joke is on us I guess. But it is a bit unfair to student pilots who might be trying to learn this stuff, and unfair to the owner of the site who is trying to create a useful resource.

If there are major errors (which there are in many of your posts) pointing out the errors should be enough. But as with most things, it is slower to correct errors than to make them. What qualifications do you have that you come and give "lectures" and call people who disagree hecklers?

See the F104: https://en.wikipedia.org/wiki/Lockheed_F-104_Starfighter Also from the Wikipedia article: the aircraft designers developed a boundary layer control system, or BLCS, of high-pressure bleed air, which was blown over the trailing-edge flaps to lower landing speeds by more than 30 knots

I don't think that was the best L/D, also I'm not sure that 2d numbers are comparable to real numbers for a 3d wing. It's not very surprising that a very thin wing works well at high speed with less drag than a thick wing. It would have been more interesting to increase AOA to recover the lift and see what happens, rather than increase speed.

I don't know... I think the biggest problem converting to tailwheel is unlearning bad habits from tricycle. The #1 bad habit is relaxing when the main wheels touch down. I flew tailwheel before first solo, and at that point you really don't know any difference. You do a lot more circuits when learning than during an endorsement, and the biggest difference is that with a tailwheel you have to work harder in the seconds after touching down. That is just dead time in a tricycle. The tailwheel aircraft gives feedback on your landing every time, better than the instructor in a tricycle.

That sounds a bit like the aircraft I flew with the tight tailwheel - it was very hard to get it to turn. Although with a tailwheel you do often need opposite rudder through the turn to stop it tightening up - it is not a case of rudder to start the turn, opposite rudder to stop it. It's rudder all the time.

As has been pointed out taildraggers are directionally unstable, but this is at medium speeds and above. At low e.g. walking speed they can actually be more stable due to the distance between the tailwheel and main gear. However... they typically have chains and springs between the rudder and tailwheel. Some aircraft have these very loose, some tighter so they will have different steering response through the tailwheel. I can imagine with the loose ones the tailwheel steering might feel vague - although the looseness might be necessary so it isn't too sensitive at higher speeds. One of the aircraft I did my endorsement in was a Decathlon where the tailwheel was done up so tight it would barely respond to the rudder pedals (I suspect to stop shimmy). It was bad enough the instructor had helpful advice like sometimes to turn downwind you need to do a 270 degree turn in the opposite direction due to weathercocking. At the end of a lesson my legs were worn out and shaking from pressing the rudder pedals to try to get it to turn while taxying (in hindsight I think I was just pressing on the rudder stops). It was a revelation when I went elsewhere and flew a Decathlon where the tailwheel was loose enough to steer...

That's a pretty black and white statement. It's either true or it's not. If the pilot doesn't have the qualifications it's nothing to do with the aircraft.

I'm pretty sure the responsibility is 100% on the car driver to make sure they have the appropriate license for what they are driving. But I don't see any claim like that in the ad anyway. What if a vendor claimed a 28 knot stall speed and it turned out that was IAS and the real stall speed was higher, also the claimed stall speed was at 450kg not the higher MTOW allowed in Australia?

Most of these conditions apply to an aircraft or engine type, they are not issued to a specific aircraft. The exception is 262AP which is an authorization to operate over built up areas, which is issued to a specific aircraft. I would expect that authorization to go with the aircraft if it was sold, I think it is effectively forms part of the certificate of airworthiness.

This is a good illustration of the problems calculating your own factors. The speeds need to be calculated based on Calibrated Airspeed (CAS) which is IAS corrected for errors due to the location of the pitot/static ports on the airframe. These errors are significant at low speed in a C172. Stall speed with flaps in a C172 is 48 KCAS. Without flap is 53 KCAS. So 1.3 x Vs0 is 63 KCAS. If you want to calculate a minimum maneuvering speed of 1.4 Vs1 that is 74 KCAS. Before use these need to be converted to IAS, but the errors are smaller at these speeds. 74 KCAS is about 75 KIAS. 63 KCAS is 60 KIAS. 60KIAS is the lower bound of the book approach speed (60-70 KIAS) so it works out. These are pretty slow speeds to be operating a C172, particularly at MTOW. 70-75 KIAS is probably reasonable for slow operations with 10-20 degrees of flap. If you need slower, you probably want a helicopter.

Marking the airspeed indicator in IAS seems pretty simple. There is one person who brought TAS into the thread via attempts to use the lift equation. I have a couple of comments on the original video: Adding markings to the indicator that could be mistaken at a glance for the needle seems unwise. If you're going to do it, perhaps use short markings at the edge, similar to eg. VNE. I am not convinced that the relationships between the different airspeeds (Vref, Vy etc) that he talks about always holds. I would have to do more research on that one. In particular, Vx, Vy will have different flap settings than Vref so any resemblance is likely to be coincidental.

It can't legally be flown at all unless the pilot is appropriately qualified i.e. pilot certificate. Does that need to be pointed out?

RAA registered aircraft.

There are multiple conditions that apply to the aircraft. See CAO 95.55: 7.3 A person must not operate a relevant aeroplane in Class A, C or D airspace, or an active restricted area, unless all of the following conditions are complied with: (a) the aeroplane: (i) is certificated to the design standards mentioned in Schedule 1 to the Civil Aviation Amendment Order (No. R94) 2004 (also known as section 101.55 of the Civil Aviation Orders), as in force on 31 May 2016; or (ii) meets the criteria stated in paragraph 21.024 (1) (a) or 21.026 (1) (a), or regulation 21.186, of CASR; or (iii) is approved under regulation 262AP of CAR in relation to flights over closely-settled areas; (b) the aeroplane is fitted with an engine: (i) of a type mentioned in paragraph 6.1 of Schedule 1 to the Civil Aviation Amendment Order (No. R94) 2004 (also known as section 101.55 of the Civil Aviation Orders), as in force on 31 May 2016, or of a type that CASA has approved as being suitable for use in a relevant aeroplane; and (ii) that is not subject to any conditions that would prevent the flight; (c) the aeroplane is fitted with a radio capable of two-way communication with air traffic control; (d) the aeroplane is flown by the holder of a pilot licence with an aeroplane category rating: (i) issued under Part 61 of CASR; and (ii) that allows the holder to fly inside the controlled airspace; (e) the aeroplane’s pilot has a valid flight review for the aeroplane’s class rating, under Part 61 of CASR; (f) if the controlled airspace in which the aeroplane is operating requires a transponder to be fitted to the aeroplane — the aeroplane is fitted with a transponder suitable for use in the airspace.

Let's take Vs1 for a C172 as an example, which is 48 KIAS. If you take off at Moorabbin on a 35C day and climb to 7000 feet where it is 20C, Vs1 in TAS* is initially 50 and increases to 55 as you climb. What value "could" you mark on the TAS scale? *In fact it is not really TAS because at low speeds there is significant error in the indicated values. The actual TAS values are 55 and 61. We would need a new concept, "Indicated True Airspeed".

It's irrelevant... you can pick individual elements out that are correct. It is when you put them together they make no sense.

A change in QNH doesn't generally change air density enough to significantly effect TAS. What does affect air density is temperature and altitude. There is a big difference between landing at Moorabbin on a cold winter's morning and landing at Mt Hotham on a hot summer day. At Moorabbin the density altitude might be minus 1000 feet, at Mt Hotham over 6000 feet. If your Vref is 65 knots, one is 64 knots TAS, the other is 71 knots TAS. But the characteristics of the air speed indicator mean that 65 knots IAS is correct for both. To be blunt, it is not the definitions that are the problem. The problem is that most of your explanations are misleading or incorrect. You need to revise your BAK before trying to teach other people. It is not fair to the people who are trying to learn this stuff to post so much incorrect information.

The lift equation also uses density. It's inconvenient to constantly adjust speeds for changing density, but luckily IAS for a particular TAS also changes based on density. The density components in the lift equation and IAS conversion cancel out, which means that stall speed etc. occur at the same IAS regardless of density, and we can mostly ignore TAS except when flight planning.

It's only supposed to be twisted 6-8 turns per inch, according to the manuals

The important V speeds Vs0, Vs1, VFE are IAS not TAS. Maneuvering speed is IAS but reduces with weight. The only speed that might be TAS is VNE.

It is definitely valid to decrease weight for an airport that is hot or high. GA aircraft will normally have performance charts that allow you to figure out whether you can take off or land in the space available at a specific weight. If the answer is no, one solution may be to reduce weight. The same applies to any aircraft, however it is more difficult if there are no performance charts for weight. It is still good to be aware of the problem. You can't use the same logic to increase weight because you don't know the limiting factors for MTOW.

Also the engine power is reduced (unless you have a turbo) so acceleration is reduced which increases the time it takes to get to the higher speed.

I'm not sure what you mean by "flys badly". If it truly flys badly it probably isn't a temperature thing. There are a number of factors that might influence MTOW: - Structure - how strong is the airframe? - Regulations e.g. a limit on MTOW or stall speed - Performance - the ability to climb after takeoff, or go around in landing configuration Temperature and altitude (i.e. air density) affect the true airspeed you need to fly and also the power available from the engine i.e. decreasing density has a double effect. It is possible to translate a high temperature into an equivalent lower temperature at a higher altitude. This is part of the performance subject in the PPL syllabus. It's more likely to be part of runway distance calculations than absolute MTOW though. I guess it is possible to have density limits on MTOW for climb performance, but I can't think of any examples.