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tafisama

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Posts posted by tafisama

  1. You do not need to worry about adding any more ballast.Your weigher has done it all.I believe the Rotax  engine with radiator weighs more than the Jabiru engine.That would have put your cog forward so to prevent that,thats why that ballast of 2.5kgs has been added.I have checked your cog with a pilot only with weight of 80kgs with no baggage and no fuel,it is 229.36mm which within both  forward and aft limits.With 100l of avgas,pilot and no baggage ,it is 263.72 which is well within both forward and aft limits.

    There is nothing to correct unless you want to reduce weight of your ballast to move cog  more forward.

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  2. With regards to horizontal stabiliser,I had an aerobatic instructor show me the good design.The horizontal stabiliser needs to sit well above the wing level so that in a stall the turbulent airflow above wings does not inhibit rudder effectiveness as more smooth air is flowing to the rudder.The other design is the one pointed above where the rudder extends below the horizontal stabiliser,again letting smooth airflow past part of the rudder.These old instructors we have here are a valuable resource.Kev I will show you next time we meet at the club.

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  3. So if it doesn't meet LSA standards,does it meet GA standards.What I have heard is LSA standards state or require an aircraft to come out of an incipient spin without much control input from pilot and enter into a spiral dive.A C152 is one such aircraft I know of though it's not an LSA.However some of the Bristels that have crushed were GA registered which means GA pilots are failing to recover.The Statwell incident I know of happened at very low height.I am not sure if they recover easily at height.I have flown a Roko which recovers at height but any unco ordination at stall,it drops a wing violently.I hope DJP will be able to share his views here.

  4. There is no "aircraft tends to have a steep nose in a climb" - this is either a conscious decision by the pilot  eg to clear a hazard OR a failure by the same to make appropriate control inputs.

     

    For the FK9 if you climb at stated climb speeds when the prop is configured to climb,you will have a much higher nose attitude.You will basically have no forward vision.All you see is blue.As a result you end up climbing at higher speeds when you lower your nose to have that forward vision.

     

     

  5. As Im just starting out. Could you explain what you mean by "tents to have a steep nose in a climb"

     

    Cheers

     

    You made a typo which  has changed the meaning.Anywhere you will realise what i meant when you fly a different type.Dont worry about it.

     

     

  6. I am signed off on that type.Jabiru 7252 has said it all.At Gawler we preferred not to use flaps for take off when the prop was adjusted for climb,however when they changed it to cruise we would use flaps but quickly retract them.The aircraft tends to have a steep nose in a climb.

     

     

  7. Don’t know the figures, but having flown a Bristell, I would say I’m not surprised if a student broke the occasional plane.  They look great and fly pretty good, but they are sensitive and I think a student might struggle at times.  I fly a Liberty XL2 and can draw a similar comparison.

     

    I’m always perplexed by the number of incidents as the plane is really easy to fly, warns you well ahead of time if you are trying to kill yourself via a stall, yet ppl stall and crash them on landing.  I suspect because they are also quite light on the controls.  

     

    Interesting Paul,I have said the same thing to my colleagues.I fly the Liberty XL2 well because I have flown the Roko.The Libery though is much steadier and balanced on stalls.

     

     

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  8. Include accidents of similar types by the same designer. Especially interested in stall/spin accidents. I wonder if the ATSB will publish independent flight tests on its stall characteristics conducted a little while back.

     

    For sure it should be interesting read.My club owns the sister a Roko NG4 which is only flown by members with 50 plus command hours.There is a general feeling no one should be practicing stalls without an instructor.It has violent stall characteristic especially when it yaws just before the stall.Lovely to fly though and stalls below 38knts.

     

     

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  9. All good advice above. Because RAAus flying and endorsements are 'recognised' by CASA for conversion to the RPL, it's wise to do your cross-country endorsement in RAAus - before shifting to the GA side. It's not smart to short-cut your navigation training and do just the bare minimums, (12hrs), as required in RAAus. I suggest you should have done at least 2, better 3-4 solo navex under RAAus and have around 20+ hrs total navigation before RPL. It also helps if your RAAus training is 'heavy' on attitude flying, and that you can actually fly with reference to instruments only, (limited or full panel), before RPL.

     

    happy days,

    You are very right,I made a big error but then my school seemed not to fully understand how to have Navigation added onto RPL.Casa could not add Navigation because I had no Instrument time.It is because of these endorsements that I found going for PPL would be wise as they are embedded in it.

     

     

  10. I did exactly what you are planning to do.Did my RPC with all endorsements at Gawler in the J170C and D.Moved to the J230C.Later because of wanting CTA and heavier machines ,went to Parafield in a C172.That was expensive.I already had RPL from CASA all I needed was a Flight Review.The C172 was very different to handle, and I spent a lot of hours trying to master it, at the same time doing Navigation.I finally passed my PPL tests BUT THAT WAS VERY EXPENSIVE.So the cost for RPC and endorsements was under $5 000 but for PPL alone it came to $20 000 because I would run out of money and spend over 8 weeks without flying and when I came back,it will be like starting afresh.Navigation was my biggest killer at times flights would be 3.2 hours @$360/hr plus landing fees.

     

    I dont regret though.

     

     

  11. I doubt that it is programmed that way. But, if it gives a pitch down command and it doesn’t get a reduction in AoA ( because the pilot is pulling up and because the AoA probe is lying), it will keep adding down trim until it gets the AoA reading that satisfies the computer, or runs into the ground. 

    They need to work on that aspect.It should not trim the elevator full down.I believe pitching down to 10° up limit would save souls.I am not sure what the normal climb attitude is for this jet.We will be hearing soon what they have actually done in the new software but if its still set to trim full down, they have not done anything meaningful.I am not sure why the engineers missed it earlier.When you pitch down to prevent a stall,you just ease the stick forward not push it all the way.The furthest it should travel is to neutral elevator position though I would prefer a 5° pitch up attitude so that the aircraft keeps climbing if it was already in a climb. Lol they might need to add an Elevator position sensor as well which will prevent the elevator to be trimmed full down.

     

     

  12. The biggest question should be ,why did the aircraft fail to climb out.It never reached 2500 feet.Why were the engines not producing enough thrust/power.The MCAS comes in to pitch down in an impending stall.I believe there is more and hopefully Investigators will pick it.Did they have a stuck down trim tab that forced the elevator full up.Did the pilots program wrong weight into system.I believe the MCAS came into effect after the system detected a stall was imminent,so to me it was responding to a crisis just like a fuse will blow if high current passes through its rated capacity.We are mostly focusing on the result not exploring the causes.Why did the aircraft fail to climb out???  

     

     

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