Jump to content

aro

Members
  • Content Count

    361
  • Joined

  • Last visited

  • Days Won

    2

aro last won the day on December 18 2017

aro had the most liked content!

Community Reputation

320 Excellent

About aro

  • Rank
    Well-known member

More Information

  • Aircraft
    C172
  • Location
    Melbourne
  • Country
    Australia

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. More information about how accurately they flew the book figures would be useful. E.g from an online POH the C182 performance calculation is based on an initial climb at 58 KIAS. If you let the speed build past that it will use a lot of extra runway. Allowing the speed to build to 66 KIAS would account for at least 30% extra ground roll compared to 58 KIAS. (66/58 squared, which assumes constant acceleration. Real life is probably worse) Likewise the landing figures specify heavy braking. They said they used moderate braking which could easily account for 30%. Another thing to be aware of with braking - braking early when you are still going fast counts the most. Heavy braking when you have already slowed down doesn't make as much difference - the runway is already behind you. Having said that, the book figures are very short and most of us would be challenged to achieve them. 433 feet is 132 metres. Add 50% and you are still below 200m, which would make you stop and think in a 182 I reckon...
  2. As a rule, the airworthiness standards do not apply to EAB aircraft. No-one is going to certify your EAB aircraft is airworthy or meets any airworthiness standard. That is 100% up to the builder. You can build what you like, and power it with whatever you like. Then it is between you and your AP what restrictions need to be applied in the interests of public safety. For the original question, you definitely need to talk to the SAAA. They have people who are on top of all the details.
  3. For a VH registered EAB aircraft, the details are in CAR 262AP: (4) A person must not operate an experimental aircraft over the built-up area of a city or town unless authorised to do so under subregulation (5). (5) CASA or an authorised person may authorise a particular aircraft to be operated over the built-up area of a city or town subject to the conditions and limitations CASA or the authorised person considers necessary for the safety of other airspace users and persons on the ground or water. As far as I know there are no specific requirements for engines etc. It is all down to the judgement of the Authorised Person whether it is permitted and what conditions and limitations are applied. If you are planning building and want the ability to fly over built up areas, it would be worthwhile to talk to the SAAA and an AP who could issue the authorisation, and see what they would consider disqualifying. Even if you have a certified engine there can be other reasons the authorisation might be denied, e.g. the particular aircraft design, build issues etc. But the earlier you talk to the AP about what they would require, the better.
  4. I don't think that there is any intention is to do an evaluation of quality or to uncover fly-by-night or backyard operators. The intention seems to be solely to ensure that the kit meets the major portion (51%) rule. So it is intended to uncover operators who provide a kit that is too complete i.e. not enough work for the builder to meet the major portion rule for amateur built registration.
  5. I'm fairly sure there isn't a fuel pressure gauge in the injected C172 I have flown. Fuel flow definitely, but not fuel pressure.
  6. The OP is flying in Switzerland, most of the replies relate to Australian procedures. Without being familiar with Swiss procedures it is hard to provide advice. I'm not sure that there is much else that could have been done - it sounds like one of those close encounters that are very rare but hard to avoid. Turning may or may not help - a turning aircraft is easier to see, but banking also creates a much larger profile for a collision.
  7. Serves me right for trying to reply to 2 messages in one post rather than double posting. Only #1 was referring to your message. The rest was in reply to Turboplanner. My argument is with the assertion from Turboplanner that: I doubt that that information is in BAK because it is often not true. (You would know better than I what is in the BAK, I am happy to be corrected.) The full flap balloon over an obstacle is often (wrongly I think) taught as a way to get extra obstacle clearance over the POH/AFM technique. Either way I don't think using full flaps for obstacle clearance is good information to give to a student studying for BAK.
  8. It was me who said that. I wasn't suggesting that you crashed, just that it wasn't a technique that should be taught in BAK. 70 feet is a big balloon. The technique was demonstrated to me when I did my PPL, from memory the typical balloon was 10-20 feet. It was supposedly a way to clear fences, not trees. You can't create energy from nowhere. The energy for a balloon comes from airspeed. Flaps may be useful if your airspeed is low enough that trading it for altitude puts you at risk of stalling. However in that case you only have energy available equivalent to the difference between stall speed with and without flaps, which isn't 70 feet worth in our aircraft. If you started at 100 knots and had 70 feet worth of balloon energy, the elevator should have been sufficient. If the flaps cause extra drag, you will end up with more energy at the top without them. However flaps might change the trim enough that the aircraft pitches up with less elevator input, giving the impression that the flaps produced the climb. Consider the situation in this thread: For maximum performance (recommended for high density altitude), he needed flaps 0 and 59 knots. Instead they had flaps 10 (flaps 10 recommended climb is 56 knots) and 65-70 knots and at the high density altitude they weren't climbing. Do you think dropping full flaps would have helped them over an obstacle? It might have given them 10 feet if they timed it right, but then they would have been sinking rapidly. As I said in that thread, know the configuration that gives best performance and the speed you have to fly to achieve it. You can put that in the BAK.
  9. Every time I line up on the runway I rely on the theory of flight, I haven't been disappointed yet. If you feel you have discovered situations where the theory doesn't hold, people would be interested. Just pulling back at 100 knots and trading altitude for airspeed should give you about 200 feet by the time you're down to e.g. 70 knots. You can try this at altitude if you don't believe the theory. Setup for 100 knots straight and level, pull back into a climb without touching the power - by the time you are down to 70 knots you should have gained 200 feet.
  10. Full flap would be unusual though? There is folklore that I have heard a number of times that the best way to clear an obstacle is to put in full flap as you fly towards it. Sure, the aircraft is initially likely to balloon. But what happens then? Maybe you climb away - depending on the airspeed and the aircraft, maybe even at a greater angle. But depending on the airspeed (e.g. too high) you could even sink again. So you really need to time the flap input. When it works, people are around to tell us. When it doesn't, maybe not... I hope this is technique is NOT actually being taught as part of BAK.
  11. Sure, but I suspect that you would have made it over without flaps as well. It was the "slowest forward speed and maximum climb was full power and full flaps" bit I was querying. Particularly in a BAK thread. It's not generally true, and shouldn't be taught in BAK.
  12. Pretty unlikely. Flaps add heaps of drag, to give a better angle of climb they would have to allow you to slow down more than they impacted your rate of climb e.g. 10% less climb but 20% reduction in stall speed would give you a better angle of climb. But it seems unlikely that flaps could reduce the stall speed enough without adding too much drag. The POH will have the answer, does it require flaps for best angle of climb? (Which is different to an obstacle clearance takeoff.) Flaps will certainly allow you to get off the ground sooner, if you are already flying they will not help you climb.
  13. I agree about the weather, it looks like the rain caused a down draft which translated into a strong wind blowing away from the rain, the same direction they took off. This is probably a common danger if you're taking off to beat weather. I gave them the benefit of the doubt on the mixture, they said "mixture set" rather than rich, and it didn't look fully rich. The flap setting is a very important point. I looked up a C172M POH online and definitely flaps 0 would be appropriate, particularly at high altitude. I disagree about the speed though. Waiting for 65 knots to rotate or climbing at 65 knots would degrade performance. For a maximum performance takeoff the POH specifies Flaps 0 Climb speed 68 mph (59 knots) until obstacles are cleared. For a flaps 10 takeoff, 65 mph (56 knots) until obstacles are cleared. Flaps 10 gives you a lot of extra drag. Too fast as well gives you extra drag squared. (Obviously that is slow and could be a problem in gusty conditions like this. Gusty winds and a requirement for a maximum performance takeoff might be a good reason to stay on the ground.) Often during training a few extra knots are added for "safety" and comfort. That doesn't usually matter because we usually have performance to spare. However, it can be deadly if you really need that performance. If there is any doubt about takeoff performance, know what configuration gives you the best performance, and know what speeds to fly to get it. However, whatever the reasons for the problem, the abort decision was good. Problems can happen to anyone, and it would be easy to sit there in denial and wait for the aircraft to climb until it is too late. Takeoff accidents are statistically much more deadly than landing accidents.
  14. CAO 95.55 has the answer. The requirements for an active restricted area are the same as for other types of controlled airspace.
  15. I don't have absolute faith in CASA - quite the opposite. I am saying that CASA do not always act according to the regulations, but if CASA say you must do X then (in practice) you must do X even if the regulations say something different - unless you want to take them on in court, which as you point out might not be a good idea. I am saying that (CASA permitting) we should be operating according to the regulations as written, not as interpreted according to unwritten principles behind them handed down through folklore.
×
×
  • Create New...