NZ Sonex

[kiwiaviator]

https://www.stuff.co.nz/national/122474981/pilot-killed-in-light-plane-crash-at-taki-airfield-civil-aviation-authority-confirms

[eightyknots]

https://www.stuff.co.nz/national/122474981/pilot-killed-in-light-plane-crash-at-taki-airfield-civil-aviation-authority-confirms

 

Very sad to hear.

 

My condolences to the pilot's loved ones!

[IBob]

https://www.stuff.co.nz/national/122578583/propeller-fell-off-plane-before-taki-crash-that-claimed-life-of-pilot

[RFguy]

If you lose a prop, does the CoG change sufficiently to result in LOC ?

Edited August 26, 2020 by RFguy

[kgwilson]

No. The loss of a prop turns your aircraft into a glider. A wooden prop is also very light. There will be a sudden loss of airspeed so the nose needs to come down instantly especially if the aircraft was climbing out under full power. The prop coming off may have been the result of something else that happened that could be the main contributor to the crash.

[RFguy]

Prop could collide with airframe ?

If aircraft was tail heavy already, might not help losing a couple of kg off far fore.

 

What is really obvious in my aircraft drag/glide calcs after engine fail is these low weight LSAs have very little in the way of inertia. When they are in a high lift/drag configuration, they stop ! A bit like racing very small sail boat. if you turn the boat off the wind they stop in a couple of meters....

[Downunder]

An aircraft may glide better without the prop as it has less drag.

 

In an ultralight you push nose down to maintain airspeed when power is lost. This is virtually instant, power lost-nose down. The instructor will train and test this. I always get it in my bfr. They want to see you push the nose down straight away.....

 

The GA theory of "use airspeed and momentum to gain altitude" does not apply.

[kgwilson]

There have been many instances of props coming off aircraft, one at our airfield a few years ago. When that happens the prop no longer has the drag of the airframe and it spins away in front of the aircraft before falling down. It is possible that the prop collided with the airframe if the pilot got the nose down straight away.

[RFguy]

ok got it. I presume there is a dangerous time on climb where engine stops, and it takes a human a finite amount of time to compute and act. Which is a good reason to practice. But I would think needs non triggered practice. knowing that it is coming is not the same.

 

<The GA theory of "use airspeed and momentum to gain altitude" does not apply. >

That would probably still apply in a dive after recovering from a developed spin ? But agreed, a corner case.

anyway, off topic, sorry !. this is about the sonex.

[Yenn]

No matter what, to lose the prop is certainly going to affect your C of G,. What often happens in this type of situation is that the prop is damaged and way out of balance, which gives massive vibration, just when you don't need it.

[Bruce Tuncks]

There is "out of balance" and "catastrophic out of balance". I reckon a wooden prop, even if it put you just out of legal balance, would not cause a crash. I agree that there must be more to the story.

A Jabiru in SA lost a blade from an experimental 3 blade prop. The resulting vibration nearly tore the engine off. Luckily, the ignition wires went before the engine was completely lost. So the pilot could still fly it ( engine with one good mounting bolt ) down to land. I wonder if it was still in legal c of g.