The great "Balls to the Wall" Challange, GT450 vs Whirlwind 912s

[LeighFly]

Hi All

As a complete "Nube" to this forum, I don't profess to have any expertise about flying or the legalities of bringing a new craft to the market.

However, having read the accident report, I can say that one very valuable lesson I have learnt, (which has not been mentioned) is not to do a 360 degree tight turn in a Trike (of any type), especially at low altitude. That's the lesson for me and hopefully other less experienced pilots like me.

I agree that there were many laws and regulations broken in this instance, but they were not the root cause of this accident. This accident could have happened on any trike, so it does not, in my mind, in any way speak about the capability or design of the new trike in question.

I hope I have not stepped on any toes .

Kind regards
Leigh

[Biggles]

I have a feeling that the main body of teh report originally included personal factors that tried to explain why the pilot did what he did and maybe there is a recent divorce or financial difficulties. This was then editted out but the addendum remained. Poor editing.

Might I speculate a little more... I have flown into my own turbulance on several occasions and when doing 360s I anticipate it... a bump. Feels within the envelope and could not be considered severe. So why was it such an issue in this instance? I would speculate that the aircraft was preforming a slow/ low turn and was close to stalling anyway? wake turbulance would then have caused the stall?

[kloot piloot]

Bobthebuilder and Morph have reitterated the importance of compliance, an issue which is not negotiable and which I fully endorse. I have the thankless job of safety officer at FABS and it was with pain when I had to ground a fellow MPL a while ago due to no ATF (Authority to Fly) and an expired pilot's license. Not to mention the grounding of a C206 pilot. Nice ? No. But CAA has vested powers to GA, and we need to apply this rule, or we will get even more regulated.

But Leighfly and Biggles' recent posts is the reason for my reply. In another thread on this forum, Capt Jordaan (CEO of CAA) is quoted as saying that the purpose of a report is to "prevent a re-occurence" of an accident.

Notwithstanding the sequence of events or the legality of either pilot or plane, Leighfly correctly summarises (from the accident report) that the accident resulted from flying into your own propwash. Hoorah !

360 degree turns with power on: Stay level or maintain a slow clinb rate
360 degree turns with power off: Anytime

[bobthebuilder]

Here's a theory.... This could cause a bang......

Flying into your own wake turbulence is not that much of big deal and IMHO, was probably not the sole contributor to the accident.
But..... What if it was handled all wrong?
We know that the trike was banked over in a turn. At a bank angle of 60 degrees, your stall speed is doubled. So, if the pilot got a fright when he hit his own wake turbulence (moderate bump) not having experienced it before, panicked, and took his foot off the power, a stall is very possible. Particularly if the bar is pushed a bit.

Yes / No / Maybe?

[Wargames]

Here's a theory.... This could cause a bang......

Flying into your own wake turbulence is not that much of big deal and IMHO, was probably not the sole contributor to the accident.
But..... What if it was handled all wrong?
We know that the trike was banked over in a turn. At a bank angle of 60 degrees, your stall speed is doubled. So, if the pilot got a fright when he hit his own wake turbulence (moderate bump) not having experienced it before, panicked, and took his foot off the power, a stall is very possible. Particularly if the bar is pushed a bit.

Yes / No / Maybe?

Don't know. To explain.

1. Your stall speed does not double when banking 60 degrees. Your stall speed do increase, and is a factor of each wing's shape and characteristics. Let me explain: What you were trying to say was that when banking 60 degrees, and keeping at the same altitude, you will fly at 2G's. This mean that the weight is twice than normal, and thus to keep level your angle of attack will be increased. But the stall is still a factor of the wing and not double.

2. When flying in your own wake, or turbulence for that matter, the aircraft will always bank away from the turbulence. So, you will not be in the wake that long (maybe 1s at the most) to really panic or get tired of fighting the turbulence.

To answer your question is difficult, because anything could have happened.

What ever happened, should not have happened. IMO 95% of all accidents is pilot error. This one is not different.

[LeighFly]

Having had a scary moment once, when following another trike at low level, I suspect that there may be another factor in this equation: Ground Effect.

If you are flying on the "back of the drag vs speed" curve, i.e. slow and low, the amount of "wake turbulence" or "vortex" is much more significant than if you are flying fast.

On the occasion when I was following another trike (in my Windlass) we were all flying quite slow and as we went round a gentle bend, the wake from the trike in front of me, nearly flipped me upside-down. This was way worse than the "bump" that you feel when circling into your own wake at relative high speed and altitude.

The question is then, how to make sure you avoid wake turbulence (your own or someone elses) especially when flying close to the ground. At high altitude, you generally have enough space and time to recover, but close to the ground, even a slight "wobble" could cause a crash. I guess this also highlights some of the dangers of very low flying, as well as following other trikes etc.

Just another few cents from my own (limited) experience

Regards
Leigh

[bobthebuilder]

I had a similar experience when a gyro flew straight over me while I was on final approach and landed in front of me. That was a lot more than a quick jolt.

Wargames, I'll pull the books out tonight and see what I can find regarding stall vs. bank angle.
I think we get the principle, but need to get the wording right.

You are right though, circling through your own wake turbulence only gives a quick thump. It's not prolonged.

[Asterix]

LeighFly - to answer your question about avoidance of what we know as propwash -

1. Your own - don't go through 270,

2. Flying behind another trike - fly higher than the leading trike - propwash will normally "fall".

3. If you suddenly smell burned two stroke oil - brace yourself - you are now in propwash!

[Asterix]

LeighFly wrote:

"Having had a scary moment once, when following another trike at low level, I suspect that there may be another factor in this equation: Ground Effect.

If you are flying on the "back of the drag vs speed" curve, i.e. slow and low, the amount of "wake turbulence" or "vortex" is much more significant than if you are flying fast."

Failed to comprehend what you wrote here first time. Over and above my answer above about propwash:

1. You should never fly at or near the point where you can fall behind the power curve - regardless of your altitude. You are going to get into an irrecoverable stall / tumble. The trikes' ass is gonna drop and you will probably not get out of it.

2. Low and slow is a NO. You will always need any one of the following - 1) Altitude 2)Airspeed.

The wake turbulence / propwash becomes irrelevant when you are behind the powercurve or low and slow. You now have bigger fish to fry.

just my two cents! Enjoy!