Ooh now come on ladies put those handbags away! It's getting more and
more like Prime Ministers questions.
On 27 juin 11, at 13:34, Jos Okhuijsen wrote:
>
> David, good friend,
>
> Thanks for your honest explanation of your bias towards Woodcomp.
> Your position, as their unpaid salesman must be awkward, and it must
> be very difficult to change your position.
> I on my turn have to admit that it has taken a long time to recover
> mentally and be able to reason clearly and stronly about the accident.
> Your next quote takes us to the cultprit of our difference of
> interpretation of the facts.
>
> "and it was apparent that the blades were close to zero pitch, so
> that regardless of how they got there it would be safe to say that a
> similar accident could not happen with an SR3000 that does not have
> the reverse option (which is not accepted by the LAA following your
> accident), as the standard props have not only electronic stops at
> the fine limits but also mechanical ones. "
>
> According to woodcomp, invited by the inspector, the blades were at
> a flyable pitch. Remembering the lack of thrust, and the
> overrevving, they must have been at a positive angle, NOT REVERSE,
> but with a pitch not enough to stay airborne.
> Why stopped the motor at that blade position and not later or sooner?
> Because, at the same moment the microswitch should cut in, it burned
> with a short circuit to ground, defying it's purpose and allowing
> the motor to run further. Next, adding throttle, the controller
> jumped in, reversing the polarity of the motor. The voltage now came
> direct, not anymore over the motor, on the microswitch and the
> breaker popped.
>
> Blaming the accident on the reversbility of the prop, thus assuming
> that a mechanical endstop makes it impossible for the prop to turn
> too fine to fly is mute as long nobody ever has checked that
> mechanical endstop.
>
> Sofar i have not heard of anybody who has checked this mechanical
> endstop on the non-reversable prop. Unless somebody, preferrably
> you, shorts or otherwise disables the end switches, and runs the
> motor till it jams, relying on the mechanical stop is not very wise
> to say the least. It would be also interesting to know if the gears
> would survive such a try.
>
> Has the LAA approved the feathering version? There is no mechanical
> endstop on the course side. Even more people will be relying on non
> reliable microswitches.
>
> I think it was Mark of Smartavionics who told be about Woodcomp
> banning its product. Mark, correct me if i am wrong.
>
> Next one:
> "The microswitches have changed over the years largely to improve
> their mechanical security but whether they are waterproof or not
> seems a bit irrelevant. I have flown through prolonged rain and
> found no problems, and you would expect that any water finding its
> way into a structure rotating at 2000+ rpm would very rapidly find
> its way out again. If you had parked the plane under a waterfall and
> the spinner was full of water before start up you might expect to
> notice problems when you switched on and went though the recommended
> pitch change check. "
>
> I read that as "there have been problems with the microswitches over
> the years". I challenge you to find any application were
> microswitches are used in open air. None are to be found in cars for
> example. As for flying in rain, and the behavior of water and air on
> a spinning service, have a look at any centrifugal pump. The
> backplate of the spinner, where the switches are and the big end
> opening in the cowl form such a pump. The rotating plate sheds water
> and air from it's side and sucks more in..... As for the pitch
> range check: The only thing you do is check that at that moment
> things are ok. It does not improve the quality of these switches.
>
> Apart from that everybody will hopefully understand the importance
> of using weatherproof components in weather. There are classes for
> humidity for electrical components and appliances. Those
> microswitches are manufactured for dry room use. And, let's not
> forget, they are heavily underrated in current as well. Proper
> switches for the application would physically never fit on that
> backplate.
>
> I hope the LAA will review its approval. I don't quite understand
> how this item passed in the first place.
>
> Regards,
>
> Jos
>
>
> 27.6.2011 12:12, David Joyce kirjoitti:
>> >
>>
>> Jos, I count you as a good friend but have to dispute many of your
>> statements. I also will state that I am no expert, but nevertheless
>> am a very interested amateur prepared to go to great lengths to get
>> to the bottom of something that affects my safety, ( and having
>> said that Tim did spend a lot of years as a radar/ electronics
>> technician in the RAF). I have on the other hand been a sort of
>> unofficial (but unpaid I hasten to add) Woodcomp agent in the UK
>> having brought (and bought) the first Woodcomp prop into the UK and
>> then pursued the very lengthy process of getting it fully accepted
>> by the PFA.
>> As you know I was there at the accident, with the same
>> plane and the same controller and the same SR3000 (albeit without
>> the reverse option). I flew back to try to help you and
>> subsequently examined the wreckage and spent some time helping the
>> Austrian AAIB man. As the accident happened flying out of the Rotax
>> Factory Flyin it's not surprising that they were quickly able to
>> help. Secondly since Mark Burton, owner of Smart Avionics,was
>> flying with us he was quick to talk to the investigator. I may say
>> that I gave the investigator my copies of the Smart Avionics
>> controller and SR3000 handbooks and allowed him to look at the
>> complete workings of my set up which was the official factory set
>> up of an SR3000 without the reverse option that you had and without
>> the non Woodcomp/personal simplifications to the wiring system that
>> you had incorporated into the circuitry. There wasn't too much left
>> of the plane after the fire but the prop hub was there and it was
>> apparent that the blades were close to zero pitch, so that
>> regardless of how they got there it would be safe to say that a
>> similar accident could not happen with an SR3000 that does not have
>> the reverse option (which is not accepted by the LAA following your
>> accident), as the standard props have not only electronic stops at
>> the fine limits but also mechanical ones.
>> My understanding of the investigation was that no prime
>> cause could be positively identified, and if I do not misquote him
>> I believe this is also Mark Burton's view (who is also of course an
>> electronics professional.)
>> The microswitches have changed over the years largely to
>> improve their mechanical security but whether they are waterproof
>> or not seems a bit irrelevant. I have flown through prolonged rain
>> and found no problems, and you would expect that any water finding
>> its way into a structure rotating at 2000+ rpm would very rapidly
>> find its way out again. If you had parked the plane under a
>> waterfall and the spinner was full of water before start up you
>> might expect to notice problems when you switched on and went
>> though the recommended pitch change check.
>> You refer to the problem experienced by someone having some
>> teeth break on the gearing that determines the pitch angle of each
>> blade and this was promptly dealt with by Woodcomp replacing it
>> both on new models and retrospectively with a slightly heavier
>> version of the gears. Woodcomp certainly have no problem about the
>> Smartavionics controller which is the choice of the majority o f
>> the substantial number of UK Woodcomp owners.
>> Apart from your problem I have not come across problems
>> that were not of the failsafe variety, and feel that describing the
>> prop as a deathtrap is entirely unwarranted
>> Regards and best wishes David, G-XSDJ
>> You mention
>>
>> ----- Original Message ----- From: "josok-e" <josok-e@ukolo.fi>
>> To: <europa-list@matronics.com>
>> Sent: Sunday, June 26, 2011 11:46 PM
>> Subject: Re: Europa-List: Woodcomp after Sales Service
>>
>>
>>> Tim,
>>>
>>> I've sent the report to somebody who is German en fluently in
>>> English,
>>> on his offer to translate. This translation takes an incredible
>>> amount
>>> of time obviously.
>>> But, as a matter of fact, the investigator thanks me for diverting
>>> from
>>> my line of descent into an occupied office building to trees. The
>>> wreckage was badly burnt. He also reports that he had Woodcomp
>>> check the
>>> remains of the propellor, and that they stated that the blades "must
>>> have been at a flyable angle" Also there was no obvious fault with
>>> the
>>> engine. It has not been possible to determine what the cause of the
>>> accident was. You may doubt of course that i have summarized
>>> properly as
>>> well.
>>> Significant might be also that after the accident Rotax was the
>>> first to
>>> talk to me, smartavionics next, the factory was very interested
>>> also.
>>> But no question, no word from Woodcomp.
>>>
>>> I find it strange that you start an argument by telling us that
>>> you are
>>> not an expert. And reach a conclusion, which is false. I am an
>>> expert,
>>> electricity, electronics have been my profession and hobby. I know
>>> microswitches and diodes, and if i tell you they are grossly
>>> underrated
>>> and not up wet conditions, you can take my word for it.
>>>
>>> My only interest is to save your lives. If you don't want it,
>>> please let
>>> me know.
>>>
>>> So, let me explain how the prop ended in a non-flyable position, so
>>> simple that a non-expert can understand. I commanded via the
>>> controller
>>> to go finer. That makes the motor run the blades to fine. The
>>> motor runs
>>> then as long as the controller command it to go finer or the fine
>>> limit
>>> switch cuts the current. In this case, because the desired rpm was
>>> high,
>>> and i was climbing, the fine limit switch should cut in. But it
>>> didn't
>>> because it was burnt, and short circuited to earth. The controller
>>> reversed it voltage to increase pitch and we had a short circuit
>>> on the
>>> plus now. The circuitbreaker popped. The revs went to 6200, with no
>>> pull. Attempting to reset it booted the controller. Which proved
>>> it was
>>> still working, And after the boot it popped again, The accident
>>> conditions were there, low on altitude, low on speed.
>>>
>>> I find it amazing that people defend such a product. Everybody i
>>> spoke
>>> to privatly admids there have been problems with communication, with
>>> quality of parts, with forgotten or loose parts, splitting blades,
>>> whatever. Oh, of course, they will cut the blades in a banana
>>> form, or
>>> apple, or anything else you fancy as fast. Very flexible indeed.
>>>
>>> There is a good working product available, has been for years,
>>> factory
>>> choice, with only plusses but the price.
>>> Everybody makes a mistake, and i can admit it was my mistake to go
>>> on
>>> the cheap and settle for a Woodcomp.
>>>
>>> Regards,
>>>
>>> Jos
>>>
>>>
>>>
>>> 27.6.2011 0:25, houlihan kirjoitti:
>>>> Hi
>>>> Further to Jos's comments about his very serious accident I seem to
>>>> recall that the Austrian authorities planned to issue a report
>>>> regarding the possible cause. I may have missed it so can anyone
>>>> let
>>>> me know what it contained, preferably in English.
>>>> Not being an expert in these things I find I have problems
>>>> linking the
>>>> limit switch failure Jos talks about to the fact that for the
>>>> propeller to go to fully fine or even beyond fully fine to a beta
>>>> state requires the motor to be powered to drive it there. I am sure
>>>> there may be a mechanism that will make that happen but I cannot
>>>> see
>>>> how it can do that just because a limit switch fails.
>>>> Also my understanding is that Woodcomp do not support the
>>>> Smartavioncs
>>>> controller not surprising really as it is not their product and
>>>> it is
>>>> in competition with them but " banning" it is beyond their remit.
>>>> Tim H
>>>>
>>>> On 26 June 2011 20:10, Jos Okhuijsen <josok-e@ukolo.fi
>>>> <mailto:josok-e@ukolo.fi>> wrote:
>>>>
>>>> <josok-e@ukolo.fi>Hi <mailto:josok-e@ukolo.fi%3EHi>
>>>>
>>>> Sorry to remember you all that my Woodcomp prop nearly took my
>>>> life.
>>>>
>>>> I hate to repeat my words, but memories seem to be short.
>>>> The propeller i had was equipped with microswitches, which were
>>>> and ,after a change, still are not designed for outside use.
>>>> Nethertheless these switches are mounted on the backplate, open
>>>> for weather.
>>>> These switches are designed for AC 240 V, not for DC 12 V, and
>>>> the
>>>> Amp rating is way below the current going through them.
>>>> The cross-over diodes are specified for less then half the
>>>> current
>>>> drawn.
>>>> Even when activated only occasionally, it's a design flaw.
>>>>
>>>> Know to me are 3 incidents with short circuiting micro-switches,
>>>> both other pilots could land their plane without damage to their
>>>> plane or themselves. An incident with a loose gear, causing one
>>>> of the blades at a totally diffent angle then the others was
>>>> reported to me, and never made it to this forum. This seems to
>>>> be
>>>> the happy family show, which i am now spoiling. :-(
>>>> It may well be that there are others, or people never fly in
>>>> rain.
>>>> or are just very lucky.
>>>>
>>>> In my case, to the best of my knowledge, a microswitch short
>>>> circuited, taking the prop to a feather situation, shortly after
>>>> take-off. I had been flying in heavy rain for hours the other
>>>> day.
>>>>
>>>> Unless thing have changed is Jyrki the only one who understands
>>>> English, if he's not available you are on your own.
>>>>
>>>> After my incident Woodcomp banned the Smart Avionic controller.
>>>> What that means is unclear to me. As far as i know, they never
>>>> got
>>>> there own controller working decently.
>>>>
>>>> As for the figures, i've had trouble to keep up with a 912
>>>> with a
>>>> fixed prop and i was flying with a 914 and a Woodcomp 3000. The
>>>> only good figure seems to be the price.
>>>>
>>>> So in short: Save a few, risk your plane and life.
>>>> The choice is yours....
>>>>
>>>> Regards,
>>>>
>>>> Jos Okhuijsen
>>>> (enjoying his second life :-)
>>>>
>>>> . 26.6.2011 19:16, Frans Veldman kirjoitti:
>>>>
>>>> --> Europa-List message posted by: Frans
>>>> Veldman<frans@privatepilots.nl <mailto:frans@privatepilots.nl
>>>> >>
>>>>
>>>> On 06/26/2011 04:02 PM, Paul McAllister wrote:
>>>>
>>>> I was very impressed with the results that David Joyce
>>>> got
>>>> with his SR
>>>> 3000W propeller from Woodcomp. I would like to some
>>>> feedback from the
>>>> forum about there after sales experience from Woodcomp.
>>>> Please give me
>>>> the 'good, the bad and the ugly'
>>>>
>>>> I got excellent support and advice when I was ordering the
>>>> propeller
>>>> from Woodcomp directly and delivery was prompt. After that I
>>>> had no
>>>> reason to contact them again as the prop works flawlessly
>>>> and
>>>> performs
>>>> better than expected. Had to service it at 50 hours and did
>>>> that at a
>>>> local Woodcomp dealer. Found that one spinner screw was
>>>> missing and got
>>>> a complete new spinner fastening set free of charge.
>>>> Ordered spare
>>>> brushes, but at the 100 hour check I discovered that the
>>>> brushes were
>>>> almost like new and it looks like it is going to take a
>>>> long while
>>>> before I have to replace them.
>>>>
>>>> Have now 100+ hours but have had no issues with the prop.
>>>> A few notes though:
>>>> 1) I'm using the controller from Smart Avionics which is
>>>> very
>>>> configurable and able to match the prop exactly to the
>>>> engine/airframe
>>>> characteristics.
>>>> 2) I have a prop with feather capability (to anticipate a
>>>> potential
>>>> future use of the glider wings). The props with feather
>>>> capability have
>>>> a stronger and faster motor. Maybe this is the reason why
>>>> the
>>>> Woodcomp
>>>> prop behaves like a hydraulic prop and reacts so fast that
>>>> it
>>>> never
>>>> allows the RPM to surge off its target.
>>>>
>>>> Hope this helps,
>>>>
>>>> Frans
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
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>>>> *
>>>>
>>>>
>>>> *
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