Don't you just hate it when the propeller departs the aircraft?

A prospect was checking out the nifty Antares 18T
sustainer system somewhere over the forest west of ZWB,
when to his great surprise, the propeller departed.
Hell of a way to impress a prospect.

The problem is with the Solo propeller shaft with the
belt reduction system as used on, IIRC:
- Ventus CM (not V2)
- Duo T
- DG-100T
- Antares 18T
Apparently there have also been recent incidents with DG1000T.
The propeller is not identical on all the above so the
failure rates will differ.

Axel Lange has worked with Solo to redesign the offending
part and is working on EASA approvals. IIRC this will be
the 3rd or 4th AD on this part, but Axel can calculate why
it failed and also how to make a part that won't...

I don't know if there's been any communication from SH
or who else uses this particular (front belt-reduction)
Solo system.

I see DG has published some info he
http://www.dg-flugzeugbau.de/index.p...1349&tx_ttnews[tt_news]=147&cHash=cd1730aca0037e72c7b2911e83136b2e

Another reminder to always operate your motor with a
plan for failure at any point...

Aaarrrggggg....
Be safe out there,
See ya, Dave "YO electric"

On Wednesday, December 18, 2013 4:54:38 PM UTC, Dave Nadler wrote:
A prospect was checking out the nifty Antares 18T

sustainer system somewhere over the forest west of ZWB,

when to his great surprise, the propeller departed.

Hell of a way to impress a prospect.



The problem is with the Solo propeller shaft with the

belt reduction system as used on, IIRC:

- Ventus CM (not V2)

- Duo T

- DG-100T

- Antares 18T

Apparently there have also been recent incidents with DG1000T.

The propeller is not identical on all the above so the

failure rates will differ.



Axel Lange has worked with Solo to redesign the offending

part and is working on EASA approvals. IIRC this will be

the 3rd or 4th AD on this part, but Axel can calculate why

it failed and also how to make a part that won't...



I don't know if there's been any communication from SH

or who else uses this particular (front belt-reduction)

Solo system.



I see DG has published some info he

http://www.dg-flugzeugbau.de/index.p...1349&tx_ttnews[tt_news]=147&cHash=cd1730aca0037e72c7b2911e83136b2e



Another reminder to always operate your motor with a

plan for failure at any point...



Aaarrrggggg....

Be safe out there,

See ya, Dave "YO electric"

I think the Duo T uses the Solo 2350D engine/prop shaft whereas the others use the Solo 2350C.

http://aircraft.solo-online.com/

John Galloway

On Wednesday, December 18, 2013 1:14:56 PM UTC-5, wrote:
I think the Duo T uses the Solo 2350D engine/prop shaft
whereas the others use the Solo 2350C.

http://aircraft.solo-online.com/

John Galloway

The issue is the prop shaft (supporting the reduction
pulley and prop hub), not the motor itself.
While the Duo uses a different assembly and prop hub,
I thought the prop shaft was the same part, but I
am not sure... Also the Duo T's banana-prop may
produce lower fatigue-loads than a two-blader,
again I'm not sure... Anybody have any info from SH?

Be careful out there,
Best Regards, Dave

"Dave Nadler" wrote in message
...
A prospect was checking out the nifty Antares 18T
sustainer system somewhere over the forest west of ZWB,
when to his great surprise, the propeller departed.
Hell of a way to impress a prospect.

The problem is with the Solo propeller shaft with the
belt reduction system as used on, IIRC:
- Ventus CM (not V2)
- Duo T
- DG-100T
I'll bet any money the problem will turn out to be torsional harmonics.

Remember the problem with the BD-5? Some excellent research was developed
out of the problems of using a 2 cycle engine in that aircraft.

Seems I remember that one fix involved a sprag clutch (one was slipping) to
get over the torque reversal at some rpms.
--
Jim in NC


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On Wednesday, December 18, 2013 8:54:38 AM UTC-8, Dave Nadler wrote:
A prospect was checking out the nifty Antares 18T

sustainer system somewhere over the forest west of ZWB,

when to his great surprise, the propeller departed.

Hell of a way to impress a prospect.



The problem is with the Solo propeller shaft with the

belt reduction system as used on, IIRC:

- Ventus CM (not V2)

- Duo T

- DG-100T

- Antares 18T

Apparently there have also been recent incidents with DG1000T.

The propeller is not identical on all the above so the

failure rates will differ.



Axel Lange has worked with Solo to redesign the offending

part and is working on EASA approvals. IIRC this will be

the 3rd or 4th AD on this part, but Axel can calculate why

it failed and also how to make a part that won't...



I don't know if there's been any communication from SH

or who else uses this particular (front belt-reduction)

Solo system.



I see DG has published some info he

http://www.dg-flugzeugbau.de/index.p...1349&tx_ttnews[tt_news]=147&cHash=cd1730aca0037e72c7b2911e83136b2e



Another reminder to always operate your motor with a

plan for failure at any point...



Aaarrrggggg....

Be safe out there,

See ya, Dave "YO electric"

Did he buy the glider? :-)

On Wednesday, December 18, 2013 8:33:51 PM UTC-7, Morgans wrote:
"Dave Nadler" wrote in message

...

A prospect was checking out the nifty Antares 18T

sustainer system somewhere over the forest west of ZWB,

when to his great surprise, the propeller departed.

Hell of a way to impress a prospect.



The problem is with the Solo propeller shaft with the

belt reduction system as used on, IIRC:

- Ventus CM (not V2)

- Duo T

- DG-100T

I'll bet any money the problem will turn out to be torsional harmonics.



Remember the problem with the BD-5? Some excellent research was developed

out of the problems of using a 2 cycle engine in that aircraft.



Seems I remember that one fix involved a sprag clutch (one was slipping) to

get over the torque reversal at some rpms.

--

Jim in NC


Russia AC-5m's have had some prop departures due to broken shafts. I believe one resulted in a fatal at North Las Vegas about two years ago. Inspections have uncovered cracks in others. IIRC, there was a fix worked.

Frank Whiteley

On Wednesday, December 18, 2013 10:33:51 PM UTC-5, Morgans wrote:
I'll bet any money the problem will turn out to be torsional harmonics.

This is way over-simplified, but useful to think about.
And I am absolutely not expert in this area! But...
You can think of the assembly as a set of springs:
- the drive belt
- the structure between the engine and prop hub
- the prop itself

When the engine fires, it:
- stretches the drive belt on one side, loosens on the other
- flexes the support structure
- bends the prop (in both torsion and load directions)

These produce fatigue loads on all components involved.
All of which have conspired to produce numerous failures
in many different makes and models over the years,
on all of the affected parts.

Hope that helps!
Be careful out there, and ALWAYS have a plan for a failure
at all points during motor operation,
Best Regards, Dave "YO electric"

I would say a further point on the SH Turbos is that they are only started by Windmilling and do not have a Starter Motor, therefore maybe less stress with slower Windmill starts on the Belts and prop shafts!!!!

A SH Turbo Driver

On Thursday, December 19, 2013 7:15:37 AM UTC-5, Muttley wrote:
I would say a further point on the SH Turbos is that they are
only started by Windmilling and do not have a Starter Motor,
therefore maybe less stress with slower Windmill starts on
the Belts and prop shafts!!!!

A SH Turbo Driver

Um, no, the start mechanism has no affect on fatigue problems.
However, do review the TNs and/or ADs on the support structure
in your installation...

On Thursday, December 19, 2013 4:31:09 AM UTC-8, Dave Nadler wrote:
On Thursday, December 19, 2013 7:15:37 AM UTC-5, Muttley wrote:

I would say a further point on the SH Turbos is that they are

only started by Windmilling and do not have a Starter Motor,

therefore maybe less stress with slower Windmill starts on

the Belts and prop shafts!!!!



A SH Turbo Driver



Um, no, the start mechanism has no affect on fatigue problems.

However, do review the TNs and/or ADs on the support structure

in your installation...

There's a very nice article describing the engineering mechanics of prop drives at this link. If the link doesn't work, just google "bd-5 prop shaft analysis" and choose the top link.

Craig

http://www.google.com/url?sa=t&rct=j... d.cGU&cad=rja



http://www.google.com/url?sa=t&rct=j...187178, d.cGU