Trojan Gyro down near Parys 2017-11-21

What your instructor never taught you. Continuing your education and learning from others. Flight safety topics and accident/incident discussions.

Moderator: Moderators

User avatar
jimdavis
10000 and still climbing
10000 and still climbing
Posts: 13446
Joined: Thu Jun 19, 2008 7:46 am
Closest Airfield: FAGG
Location: Wilderness

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby jimdavis » Wed Dec 06, 2017 9:48 am

V5 - LEO wrote:... my guess is start looking at pilot incapacitation, medical ?, maybe bird strike to head


I am beginning to think that way too, Leo.

Actually I would like to know a bit more about exactly what work they had done on the gyro, and what he was testing.

ek
WOW! Volume 2 of Jim's new book "FLYING IN AFRICA" is out already. Get it on Kindle. http://www.jimdavis.co.za
User avatar
V5 - LEO
Tree Tousand
Tree Tousand
Posts: 3603
Joined: Mon Dec 05, 2011 4:18 pm
Closest Airfield: FYWH
Location: Namibia

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby V5 - LEO » Wed Dec 06, 2017 11:07 am

jimdavis wrote:
V5 - LEO wrote:... my guess is start looking at pilot incapacitation, medical ?, maybe bird strike to head


I am beginning to think that way too, Leo.

Actually I would like to know a bit more about exactly what work they had done on the gyro, and what he was testing.

ek


......yes that could help, maybe some of the toxins {if there were any present} taking a late or early effect????
In God I trust. The masses are never right, the minority are sometimes right, but the truth is always right.
“One good teacher in a lifetime may sometimes change a delinquent into a solid citizen.” — Philip Wylie
User avatar
apollo11
Too Tousand
Too Tousand
Posts: 2219
Joined: Sun Mar 13, 2005 8:59 pm
Closest Airfield: FAGM
Location: JHB

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby apollo11 » Wed Dec 06, 2017 12:12 pm

How robust are the bearings in the rotor head? How robust is that teeter bolt? What are the enhances of the rotor head seizing (not related to this accident just general questions)
Straighten up and fly right!
Perry
User avatar
rotorman
Forgot to remove the chocks!
Posts: 56
Joined: Fri Nov 03, 2006 9:19 pm
Closest Airfield: Pearly Beach Airstip
Location: Pearly Beach Airstrip, Gansbaai

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby rotorman » Wed Dec 06, 2017 4:38 pm

Hi Jean.

I understand your reasoning re the blade based on the roll-overs that you have witnessed. Roll-over time rate is relatively slow wrt blade RPM period and rotation is around a fixed pivot point. Consequently two mangled blades normally result. I think that in this case the scenario was markedly different. If say the normal operating RPM for these longer blades were between 300 and 350, half a blade revolution will take between 90 and 100ms. Expenditure of the total rotor energy on impact is going to take place in much less time than 100ms. With all energy expended, it comes to rest. If the forward blade is just off the horisontal when the rear blade makes fairly ‘solid’ contact, the forward blade, rotating and very stiff due to centripetal force, will still be off the horizontal by the time all rotor energy, meaning that of both blades as they are mechanically connected, is expended. Same principles apply in the cases of a vehicle smashing into a concrete wall or a bullet fired into the sand – some parts of the system absorbs all the energy of the total system and leaves the other connected parts fairly intact. The position of the ‘undamaged looking’ blade wrt the wreckage supports the reasoning. I am not arguing that this was definitely the case, but it is physycally possible and I can find no other explanation for what is seen. Therefore the ‘Do not read too much..’.

The condition of the prop blades suggests the possibility of an engine out and I was thinking of a forced landing gone wrong for some reason or the other. But then again, Crazydoc’s post shows how quickly things can go south. Thanks for candidly sharing Crazydoc.

We will sadly and frustratingly probably never know exactly what happened, only that it should not have happened.

Rgds
F
User avatar
Rotor kop
Fife Thousand feet
Fife Thousand feet
Posts: 5989
Joined: Sat Dec 31, 2005 1:43 pm
Closest Airfield: OR Thambo
Location: Wherever there is good diamond gravels...

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby Rotor kop » Wed Dec 06, 2017 5:03 pm

Just watching gyros take off looks so unatural. The angle between rotor disk and forward motion is huge. Dont know how that mast and rotor head can last. There are 1000's of them flying so it obviously works but not for me thanks.
To fly is Heavenly, but to HOVER is Divine
I'm not driving fast - i'm flying low
User avatar
jtresfon
Incorrect Read back of ATC clearance
Posts: 138
Joined: Thu Nov 25, 2010 10:01 am
Closest Airfield: Morningstar
Location: Cape Town

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby jtresfon » Thu Dec 07, 2017 8:16 am

apollo11 wrote:Once this happens is it game over right there or can the pilot throttle back and pitch up very gently to recover?


If a retreating blade stall is severe enough that blade flap occurs in flight beyond the limits of the teeter stops, i.e. causing the gyro to roll left in the sky it is pretty much game over. Prevention is better than cure! This is the reason for the very clearly marked VNE limits.

apollo11 wrote:How robust are the bearings in the rotor head? How robust is that teeter bolt? What are the enhances of the rotor head seizing (not related to this accident just general questions)


The rotors on a (modern 2 seater) gyro rotate at a relatively low RPM, normally approx 350-450 RPM during flight. Thus the rotor head bearings are not working hard and the bearing temp tends to be only a degree or two above ambient temperature. The teeter bolt is very robust. Assume an LSA max all up weight of 600kg the most g-force you could pull is less than 3g giving a total weight on the teeter bolt of around 1.8 tons. Some of the gyros have teeter bolts rated to 25 tons. The chance of a rotor head seizing is small enough to be completely discounted (assuming of course that servicing and maintenance has been carried out to factor standards by an approved person). One of the longest flying modern gyros is the Magni and to the best of my knowledge they have not had a single incidence of a rotor head failure in all their years of operation.

Regards
Jean.
ZU-RCV Autogyro MTO Sport Gyrocopter
User avatar
apollo11
Too Tousand
Too Tousand
Posts: 2219
Joined: Sun Mar 13, 2005 8:59 pm
Closest Airfield: FAGM
Location: JHB

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby apollo11 » Thu Dec 07, 2017 8:59 am

Thank you for the clear and in depth explanation Jean, most interesting.
Straighten up and fly right!
Perry
Adie
Wanna Fly
Posts: 2
Joined: Fri Nov 24, 2017 1:32 am
Closest Airfield: Fisantekraal

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby Adie » Thu Dec 07, 2017 2:05 pm

Something that is bothering me.

Looking at the ashes in the pictures again it seems as if the pilot got out of the Gyro at some stage.

A
User avatar
jimdavis
10000 and still climbing
10000 and still climbing
Posts: 13446
Joined: Thu Jun 19, 2008 7:46 am
Closest Airfield: FAGG
Location: Wilderness

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby jimdavis » Thu Dec 07, 2017 2:22 pm

Adie wrote:Something that is bothering me.

Looking at the ashes in the pictures again it seems as if the pilot got out of the Gyro at some stage.

A


Greetings Adie - and a big welcome to Avcom =D> =D> :D :D

An interesting first post. What makes you say that?

jim
WOW! Volume 2 of Jim's new book "FLYING IN AFRICA" is out already. Get it on Kindle. http://www.jimdavis.co.za
Adie
Wanna Fly
Posts: 2
Joined: Fri Nov 24, 2017 1:32 am
Closest Airfield: Fisantekraal

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby Adie » Thu Dec 07, 2017 3:05 pm

jimdavis wrote:
Adie wrote:Something that is bothering me.
Looking at the ashes in the pictures again it seems as if the pilot got out of the Gyro at some stage.
A

Greetings Adie - and a big welcome to Avcom =D> =D> :D :D
An interesting first post. What makes you say that?
jim


1. The ashes around the cockpit is undisturbed. No struggle or removal disturbances.
2. I would expect some indication of the remains like helmet etc.

Thanks for the welcome Jim, I've been interested in aircraft for many years. Did fly gliders as Swellengrebel many years ago. Tried some radio controlled fixed wing and helie's.
A
User avatar
jimdavis
10000 and still climbing
10000 and still climbing
Posts: 13446
Joined: Thu Jun 19, 2008 7:46 am
Closest Airfield: FAGG
Location: Wilderness

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby jimdavis » Thu Dec 07, 2017 5:03 pm

Adie wrote:Thanks for the welcome Jim, I've been interested in aircraft for many years. Did fly gliders as Swellengrebel many years ago.
A


Perhaps we even met there - I did some tugging and gliding there in the mid 60s.

jim
WOW! Volume 2 of Jim's new book "FLYING IN AFRICA" is out already. Get it on Kindle. http://www.jimdavis.co.za
User avatar
jimdavis
10000 and still climbing
10000 and still climbing
Posts: 13446
Joined: Thu Jun 19, 2008 7:46 am
Closest Airfield: FAGG
Location: Wilderness

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby jimdavis » Fri Dec 08, 2017 5:00 pm

I have been fast asleep. WWW?

Any chance there could have been thunderstorm activity around?

jim
WOW! Volume 2 of Jim's new book "FLYING IN AFRICA" is out already. Get it on Kindle. http://www.jimdavis.co.za
User avatar
John Boucher
1k poster
1k poster
Posts: 1987
Joined: Mon May 08, 2006 10:51 pm
Closest Airfield: Mossel Bay - FAMO
Location: Mossel Bay (FAMO)

Re: Trojan Gyro down near Parys 2017-11-21

Unread postby John Boucher » Sat Dec 09, 2017 5:52 pm

Inclement weather could just put a different "spin" on this accident?
My apologies if my spellchecker or grammatical error checker lets me down - no one is perfect!



Return to “Academy & Flight Safety”

Who is online

Users browsing this forum: Arie de Wet, CommonCrawl [Bot], DavidPilot1, Jack Welles, Jacques Le Roux, Luscombe47, Nyx, Ozone, ReonWiese, Slabfish, vgmiles, waynesavy and 1 guest