---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Thu 03/19/09: 17 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:50 AM - Re: Woodcomp Propellers (josok) 2. 04:37 AM - Re: Woodcomp Propellers (Frans Veldman) 3. 05:13 AM - Re: Woodcomp Propellers (Frans Veldman) 4. 06:18 AM - Re: Woodcomp Propellers (josok) 5. 07:41 AM - Re: Woodcomp Propellers (Frans Veldman) 6. 11:02 AM - Carriage of ELT in Netherlands (David Corbett) 7. 11:34 AM - Re: Carriage of ELT in Netherlands (Marcel Zwakenberg) 8. 11:47 AM - Re: Garrecht Ultracompact VT01 installed anyone? (zwakie) 9. 11:48 AM - Re: Woodcomp Propellers (josok) 10. 01:48 PM - Re: Carriage of ELT in Netherlands (Frans Veldman) 11. 02:55 PM - Re: Woodcomp Propellers (Karl Heindl) 12. 03:29 PM - Constant Speed Prop and failure modes. (ALAN YERLY) 13. 06:13 PM - Re: Constant Speed Prop and failure modes. (josok) 14. 08:23 PM - Constant Speed Props, etc. (Fred Klein) 15. 09:00 PM - Re: Constant Speed Prop and failure modes. (ALAN YERLY) 16. 09:21 PM - Re: Constant Speed Props, etc. (ALAN YERLY) 17. 11:03 PM - Re: Constant Speed Props, etc. (Fred Klein) ________________________________ Message 1 _____________________________________ Time: 03:50:58 AM PST US Subject: Re: Europa-List: Woodcomp Propellers From: "josok" Ok, i'll try to answer the questions asked. Some of them have been asked and anwered before, and i hope these answers will be consistent with what was mentioned before :-) Latest news from the accident investigator was 3 weeks ago, where he told me that he wanted to finish the report within a week. Maybe there are new delays. Why did the prop run into super fine pitch? I took off normally, full throttle, prop controller in the take-off position. Everythinjg fine. At 500 ft above ground i switched the controller to cruise and throttled back. The controller adjusted the blades to 4350, my last descent cruise. I had forgotten to adjust the controller to 5000 rpm, my normal slow climb cruise. As a result the map went beyond an acceptable value. So i throttled down more, and at the same time toggled the controller to 5000 rpm. This caused the blades to turn more fine. Probably against the fine endstop position, if that endstop had been functional. At that very moment the tower instructed the formation to switch frequencies, although i was still on crosswind, and number 3 probaly still on upwind. While changing frequencies i noticed that my number one was disappearing fast, added more power and noticed 6200 rpm and no thrust, 50 knots airspeed The blades were obviously in super fine. Also the prop CB had popped. Resetting the CB resulted in the controller showing boot messages as normal, and the CB popped again. Because the controller booted normally, it is clear that there was no sc in there, and the controller only did what is was supposed to do: Turn fine to increase the demanded rpm, (fine endstop being the end of travel) turn coarse to reduce to demanded rpm. Most probably the pitch motor had burnt. It could not cope with turning the blades at this high rpm. That the propellor was of a reversible version had nothing to do with the events. All components that played a role are present in any SR 3000. To resume: !st Endstops did not work, Woodcomp supplied component failure. 2nd: Motor burnt The electrical components in the propeller are not suitable for the task. The end-stop microswitches are for indoor use, and not suitable to withstand weather influences. Most probably their DC amp rating is much lower then the current drawn by the motor. The diode across the switches is of a 5 A type, where the pitch motor can draw + 15A. The motor, for which i could not find any specifications, looks to be a 6 V type. Suitable for either very short tem useage or pcm control lower then 50 %. Woodcomp had repaired the prop. After the repair i had to increase the pcm ratio from 40% to 80% to make the pitch motor run. Either the mechanism was turning far more difficult, or the motor specifications had been changed. With the repared propellor came some parts, gears, and also a used motor. As usual with Woodcomp, there was no explanation or specification. As stated before: There is no mechanical endstop in the SR 3000 (Thanks David for the addition) Not in any Woodcomp 3000, being "normal", reverse or feathering. Proper working of the fine endstop relies only on proper working of the electrical circuit. This circuit, contradictory what David states, is NOT double. it relies on a single, underrated diode!. There are 2 fine endstops microswitches, probably because their rating is insufficient. As any electrical engineer can tell you, doubling contacts does not double the switching capacity. Reason being that one will always be earlier. There will be NO indication that either the microswitches or the diode has failed, until also the motor burns and you are in superfine pitch at 500 feet and at 50 knots :-( Yes, also Rotax engines have failed, the difference is, ,that there are no underrated or misplaced components to point a finger at. There is proper documentation, and proper follow-up for anything that may cause a problem. The best Woodcomp came up with was to "No support for 3rd party controllers" That they are also the only supplier not contacting me after the accident does not make me happy either. Its only fair to admit my own mistakes. As an electrical engineer i should not have accepted the electrical setup of the prop. I should have known better. I should not have acepted their offer to repair the propellor. I should not have acceped the needed change in pcm without further explanation. I should have adjusted the cruise rpm before take-off. Maybe i should not have flown in rain. I should not have accepted the frequency change while still taking off. There were fields within range, if i would not have been distracted. If you keep flying with a SR 3000: Please add a fine endstop check to you checklist for every take-off. Kind Regards, Jos Okhuijsen Visit - www.EuropaOwners.org ________________________________ Message 2 _____________________________________ Time: 04:37:33 AM PST US From: Frans Veldman Subject: Re: Europa-List: Woodcomp Propellers Jos, Since I intent to order a Woodcomp propellor soon, I'm very interested in the cause of the accident. I'm however still puzzled by your claim that a mechanical failure of the Woodcomp propellor was the cause of your crash. I was prepared to wait for the final AAIB report, but now you are pointing to the quality of the Woodcomp propellor as being the cause of the accident, I would love to hear the complete story. You first state that the lack of an end-stop in the Woodcomp propellor was the cause. Later on, you blame diodes and relays of inferior quality. These are two different things. Anyway, as someone else pointed out already, the accident implies more or less that the propellor control motor got somehow engaged. A missing end stop was nothing more than a contributing factor, not the real cause. Since you had the reverse pitch option, there could not be a mechanical end stop anyway. But even without the end stop, the prop would have functioned correctly, IF the prop pitch motor got not erroneously engaged during the flight. The big question therefor remains: what caused the prop motor to start cranking the prop to superfine? Some of us are intrigued by a message from you, written the 19th of may 2007, in which you wrote: "For reason of simplicity, exactly in a high stress situation (most of my landings will be :-) ) managed to do away with the change-mode switch. The 3-pole reverse-unreverse switch now operates a relay, that changes the mode. This latched and warning labeled switch is IMHO security enough against accidental operation. Do you have to wait for full reverse before opening the throttle? Should i think about an indicator light that indicates the reverse end stop reached?" See http://www.europaowners.org/viewtopic.php?t=4276 In a normal setup, you can not engage reverse, without changing the mode first, and putting power back to idle first. In a standard Woodcomp setup there are no relays involved at all. You are describing a modification that bypasses the mode switch by the addition of a relay, and could potentially switch the prop to full reverse without closing the throttle first. Could it be that your safety bypass, consisting of the addition of a relay, played a role in this accident? Was this the malfunctioning relay you are referring to? If this single additional relay would fail, could it all by itself unintentionally power up the pitch control motor? I hope you understand that I'm confused by your claim that it was just a missing mechanical end stop that was the main cause of the accident. If your modification made it easier for the prop pitch motor to unintentionally start cranking the prop to fine/reverse, it doesn't make sense to point so strongly to the Woodcomp company as being the cause of the accident. So far, I have no reasons to believe that a Woodcomp prop, without reverse option, and without safety bypass, would have a higher risk than any other prop. There are no statistics that point into that direction. I'm not involved in the Woodcomp company, I even don't have a Woodcomp propellor (yet). Hope you understand that I'm purely technically interested in the chain of events that led to this tragedy. There might be something that can be a lesson for us, so we avoid this from happening again in the future. For the safety of us all, we'd better stay away from emotions and look purely at the factual data we have. At this moment, without substantial data, just pointing to Woodcomp as the cause, is not really convincing, and not sufficient ground to start talking people into selling their Woodcomp propellors. Just my 2 cents. -- Frans Veldman ________________________________ Message 3 _____________________________________ Time: 05:13:31 AM PST US From: Frans Veldman Subject: Re: Europa-List: Woodcomp Propellers josok wrote: > Why did the prop run into super fine pitch? Thanks for the information, but it still doesn't explain why the prop went into super fine pitch in the first place. Was it commanded by the prop controller? I don't have a Woodcomp propellor yet, but it appears to me that control of the prop pitch motor is some sort of feedback loop. In normal operation, I assume the prop controller won't fling the pitch back and forth between the end limits, but make small changes, evaluate the result, and not go to super fine if the RPM is already very high. Apart from this, I may assume that this system has been working correctly in the past, and that going to super fine pitch and high RPM was not part of your normal flying procedure. A burnt out motor can not be the cause of going to super fine pitch, as a burnt out motor does not do anything anymore, so I think something first powered the motor to super fine pitch before the motor burned out. Maybe the motor burned out because of this untintended move to super fine pitch. If this is the case, the burning out of the motor was not the cause, but a result of something else going wrong. > To resume: !st Endstops did not work, Woodcomp supplied component > failure. 2nd: Motor burnt The end stops, if they were there, would have been an *additional* safety, but not for throwing the pitch against its limits over and over again. > The diode across the > switches is of a 5 A type, where the pitch motor can draw + 15A. Diodes over switches are not there to let the main current through, but to extinguish the opposite voltage that appears when you suddenly take the power away from a coil. Since the motor is a coil, it will create a spark everytime when you disconnect it, and the diode is there to extinguish it. There is no reason why the diode should have the same amp rating as the current demand of the pitch motor. 5 Amps sound generously to me for this task, I bet 1 amp would have been fine as well. > The > motor, for which i could not find any specifications, looks to be a 6 > V type. The rating is something that the manufacturer comes up with, for continuous use. There is no physical difference between a 12 Volt or 6 Volts motor. It is just a rating that describes the maximum voltage for contineous usage. The same motor, with better cooling, or for shorter durations, can handle a higher voltage. It is fully acceptable that Woodcomp used a 6 Volt motor for the purpose of being used in short bursts, in a very efficiently cooled area. > As stated before: There is no mechanical endstop in the SR 3000 > (Thanks David for the addition) Not in any Woodcomp 3000, being > "normal", reverse or feathering. Proper working of the fine endstop > relies only on proper working of the electrical circuit. This > circuit, contradictory what David states, is NOT double. it relies on > a single, underrated diode!. There are 2 fine endstops microswitches, > probably because their rating is insufficient. As any electrical > engineer can tell you, doubling contacts does not double the > switching capacity. Are they wired in series or in parallel? You are suggesting that they are connected in parallel, and if so, I agree that this is a very dumb thing. However, I hate not to have a Woodcomp propellor here, but I'm betting that these switches are wired in series. In this case, if one fails, you still have the other one. > There will be NO indication that either the microswitches or the > diode has failed, until also the motor burns and you are in superfine > pitch at 500 feet and at 50 knots :-( Still, I wonder whether it is normal operation to rely on the microswitches to stop the pitch motor, or that the propellor controller is supposed to never try to command the propellor against its safety limits. Even without mechanical end stops, diodes, and microswitches, the system would have had to function normally. Until the moment that somewhere, something catastrophically started to power up the pitch motor. In the reverse circuit, there are no safety microswitches for superfine, because the prop is intentionally moved through its super fine setting. It is therefore likely that a failure occured in the reverse circuit. Something tried to reverse the prop, the controller was fighting this, with the result that the CB popped and the prop was stuck in super fine. Since you made some modifications in the reverse circuit, it is not really fair to blame Woodcomp for the catastrophic result. > If you keep flying with a SR 3000: Please add a fine endstop check to > you checklist for every take-off. This sounds to me as a wise thing to do. I will for sure add it to my check list. Thanks! -- Frans Veldman ________________________________ Message 4 _____________________________________ Time: 06:18:09 AM PST US Subject: Re: Europa-List: Woodcomp Propellers From: "josok" Dear Frans [quote:f042f8651c]You first state that the lack of an end-stop in the Woodcomp propellor was the cause. Later on, you blame diodes and relays of inferior quality. [/quote:f042f8651c] Sorry, no. The fine pitch endstop is formed by two microswitches, parelled by one diode. Never mentioned a relay. [quote:f042f8651c]These are two different things. Anyway, as someone else pointed out already, the accident implies more or less that the propellor control motor got somehow engaged. A missing end stop was nothing more than a contributing factor, not the real cause.[/quote:f042f8651c] Of course the pitch motor got engaged, not by mistake, but because the pilot, me reduced throttle. The not-working endstop was the first failing part. A burned out motor the second part. What real cause do you want? [quote:f042f8651c]Since you had the reverse pitch option, there could not be a mechanical end stop anyway. [/quote:f042f8651c] Irrelevant: Not any Woodcomp SR 3000 has a mechanical stop. Read my lips: Normal, reverse, feathering: No mechanical endstops. [quote:f042f8651c]But even without the end stop, the prop would have functioned correctly, IF the prop pitch motor got not erroneously engaged during the flight. The big question therefor remains: what caused the prop motor to start cranking the prop to superfine?[/quote:f042f8651c] Iv've tried to explain that, let's try again, real slow now, for the technically handicapped amongst us. Say you fly at 100 knots, and the controller has adjusted the rpm, as you have demanded, to 5000 rpm. Now, if you reduce throttle slightly the controller reduces the pitch to maintain the 5000 rpm that you asked for. Right? It will keep reducing the pitch at any further reducing of throttle, to keep up the RPM. The controller has no idea how fine it turns the blades. Only the endswitch will prevent the blades from turning into superfine or even further. Nothing strange about that, and nothing to worry about, IF THE ENDSTOPS ARE WORKING! [quote:f042f8651c]Some of us are intrigued by a message from you, written the 19th of may 2007, in which you wrote: "For reason of simplicity, exactly in a high stress situation (most of my landings will be :-) ) managed to do away with the change-mode switch. The 3-pole reverse-unreverse switch now operates a relay, that changes the mode. This latched and warning labeled switch is IMHO security enough against accidental operation. [/quote:f042f8651c] Some of us? Intrigued? I fail to see where this connects to this thread other then do distract from the facts. [quote:f042f8651c]Could it be that your safety bypass, consisting of the addition of a relay, played a role in this accident? Was this the malfunctioning relay you are referring to? If this single additional relay would fail, could it all by itself unintentionally power up the pitch control motor?[/quote:f042f8651c] Safety bypass? Please! If "my" relay would fail, it would either blow the CB immediatly, leaving the pitch unchanged, or simply leave the pitch motor without power, again leaving the pitch unchanged. The actual switching was done by a 4 pole 3 way switch. That switch could only do what it was supposed to do. I've shown the circuit to experts, and i have had the actual wiring checked by my inspector. His comment was "Better standard of wiring then seen sofar on experimentals" You are classifying a pretty fail-safe setup as a safety bypass, without even knowing the details. [quote:f042f8651c]I hope you understand that I'm confused by your claim that it was just a missing mechanical end stop that was the main cause of the accident. [/quote:f042f8651c] You really can't read. Never said that. I doubt very much if this is caused by confusion or else. You seem to be constructing things. It's a pity. And believe me, wish you all the luck you will need. Regards, Jos Okhuijsen Visit - www.EuropaOwners.org ________________________________ Message 5 _____________________________________ Time: 07:41:25 AM PST US From: Frans Veldman Subject: Re: Europa-List: Woodcomp Propellers josok wrote: > [quote:f042f8651c]You first state that the lack of an end-stop in the > Woodcomp propellor was the cause. Later on, you blame diodes and > relays of inferior quality. [/quote:f042f8651c] > > Sorry, no. The fine pitch endstop is formed by two microswitches, > parelled by one diode. Never mentioned a relay. You are right. My slip up. > Iv've tried to explain that, let's try again, real slow now, for the > technically handicapped amongst us. > > Say you fly at 100 knots, and the controller has adjusted the rpm, as > you have demanded, to 5000 rpm. Now, if you reduce throttle slightly > the controller reduces the pitch to maintain the 5000 rpm that you > asked for. Right? So, let's assume for the moment I'm technically handicapped, and let me ask just to be sure I don't misunderstand you: If you throttle back from take-off power to cruise climb, the controller tries to move the blades to the finest pitch possible, and it is the task of the endswitches to prevent the blades from moving even further? With other words, with every throttle move, the blades will always travel to one of the endstops? If this is the case, I can understand how a failed endstop immediately caused the blades to travel to a non flyable position. As I'm technically handicapped, I picture the working of the prop and controller as follows: Say you fly at 100 knots, and the controller has adjusted the rpm, as you have demanded, to 5000 rpm. Now, if you reduce throttle slightly, the controller reduces the pitch somewhat *without fully traveling to the end stop*, measure the rpm again, evaluate if still below the target rpm, reducing the pitch a little bit more, evaluate again, and stop when the engine again is at 5000 rpm. The end switch has not been used in this scenario, because the prop went never to its finest position in the first place. Even with the end switches shorted, you won't notice anything. Until something else goes wrong... For a failure, you need an additional factor, something that tries to move the blades to an even finer pitch *while the rpm is already above its target*. I'm still looking for a scenario where the rpm can rise to 6200 rpm, the blades are in super fine, and something is feeding power to the pitch motor to move the blades even further. What is this "something". Once again: even with all micro-switches shorted, the pitch motor won't run, because power is fed only to these switches if something (the controller, the reverse pitch relay) is sending power to the pitch motor with the purpose of reducing the pitch. The end switches won't see any power, shorted or not, unless something tries to move the pitch motor even further. > It will keep reducing the pitch at any further > reducing of throttle, to keep up the RPM. Past the desired RPM? > [quote:f042f8651c]Some of us are intrigued by a message from you, > written the 19th of may 2007, in which you wrote: "For reason of > simplicity, exactly in a high stress situation (most of my landings > will be :-) ) managed to do away with the change-mode switch. The > 3-pole reverse-unreverse switch now operates a relay, that changes > the mode. This latched and warning labeled switch is IMHO security > enough against accidental operation. [/quote:f042f8651c] > > Some of us? Intrigued? I fail to see where this connects to this > thread other then do distract from the facts. Let me spell it out: In a normal situation, when powering back from take-off power to cruise power, the end/stops/limit switches never come into play, because the controller cuts the power to the pitch motor long before the fully finest position is reached. In order for the limit switches to show their failure, something has to keep sending power to the prop circuit, now putting all bets on the limit switches to prevent the prop from going past fully fine. Once again: I think it is not common practice to cruise along with the prop in fully fine, so the end switches should never have been exercised. But something tried to move the blades to fully fine, and apparently even past fully fine. Now, as I studied the schematics, there are only two power sources for the prop pitch motor: the controller, and the reverse circuitry. One of these circuits had to be inadvertently sending power to the pitch motor, while the rpm was already way up. By definition, the reverse circuitry has to bypass the microswitches, because its purpose is to intentionally move the blades past fully fine. That makes the reverse circuitry suspect number one. If I then read that you have modified the reverse circuit, it is not difficult to start to wonder if this has had something to do with it. > Safety bypass? Please! If "my" relay would fail, it would either blow > the CB immediatly, leaving the pitch unchanged, or simply leave the > pitch motor without power, again leaving the pitch unchanged. If I recall correctly: on the Woodcomp there is a third slip ring, for adding power to move the prop beyond its normal flying operating range. This is used for reverse, or feathering. You need to put power on this ring to feather or go to reverse. This third ring is not connected to the controller, so the controller is no longer suspect here. Normally you put power on this third ring with a safety latched switch. It appears from your message that you replaced the function of this switch by a relay. In this case, an inadvertently close of the relay contacts would catastrophically power the pitch motor, bypass the end limit switches by its very nature, keep power on the pitch motor until it finally gives up the ghost. The controller, who sees the rpm going up, tries frantically to move the pitch motor the other way via the other slip rings. This will for sure pop the circuit braker. And will keep popping the circuit breaker as long as rpm is too high, and the third slip ring remains powered up. A failure of the reverse switch/relay would exactly give you the catastrophic results that you described. And the limit switches do not even have to fail for this scenario to happen exactly as described. This is the only "one-failure" scenario that I can think off, all other scenario's require multiple failure points are not impossible, but less likely. > actual switching was done by a 4 pole 3 way switch. That switch could > only do what it was supposed to do. I've shown the circuit to > experts, and i have had the actual wiring checked by my inspector. > His comment was "Better standard of wiring then seen sofar on > experimentals" I do not suspect the wiring failed, but that the relay failed. Relais do fail sometimes. I would love to see the schematic, to see what you have done. Then we can see which components need to fail to cause exactly the same results as you experienced. I'm sure there will be multiple scenario's. However, all these scenario's would have in common that something else failed before the failed(?) end switches came into play. > You are classifying a pretty fail-safe setup as a safety bypass, > without even knowing the details. I would love to know the details. The whole problem is that you blame the end switches, and lack of physical end stops, completely ignoring the fact that something must first inadvertently power up the pitch motor to its fully finest pitch before these end limits would come into the picture. > I doubt very much if this is > caused by confusion or else. You seem to be constructing things. It's > a pity. I'm just trying to solve the puzzle. My own safety depends on it. If I would just walk away from any part that has been involved in an accident somewhere, I could't build an airplane. It is necessary to construct how things went wrong, before you can really assess whether the part is safe or unsafe. Is a Rotax engine unsafe, because someone crashed with it? Dunno, unless I get a clear description of what was the cause. Same with the Woodcomp prop. Just be assured that my intention is not to blame you in anyway. In fact, I never got involved in the discussion about your accident. But now you so openly blame Woodcomp and completely ignoring the fact that some "non-woodcomp-part" had to be feeding power to the pitch motor for the failure to occur, it is our (Europa community) mutual interest to put things into perspective. -- Frans Veldman ________________________________ Message 6 _____________________________________ Time: 11:02:40 AM PST US From: "David Corbett" Subject: Europa-List: Carriage of ELT in Netherlands At a meeting at the UK Civil Aviation Authority on 17 march we were told that carriage of ELT is mandatory for all aircraft in Netherlands airspace. Can our Europa friends in Holland please confirm whether this is the case - I am asking on behalf of a group of UK aircraft, including my Europa, which are going to night stop at Lelystad for 3 nights en route to Norway. And - how rigidly is the carriage of Mode S above 1800' amsl being enforced? Many thanks, David UK 265 - G-BZAM ________________________________ Message 7 _____________________________________ Time: 11:34:34 AM PST US Subject: RE: Europa-List: Carriage of ELT in Netherlands From: "Marcel Zwakenberg" Hi David, Your information on ELT's in Dutch airspace is partly correct, but for you that is probably how it should be interpreted by people outside of Holland. The complete rule is: ELT's are mandatory for all traffic crossing any of the EHAA boundaries. Traffic within Dutch airspace that never crosses those boundaries do not have to carry ELT's. Unfortunately for everyone in GA, Mode-S is required for all traffic in Dutch airspace. There is only one exception: in Class G under 1200' amsl (note: not the 1800' amsl you mention!)that is not restricted by special airspace types like TMZ's etc. you can fly around without a transponder broadcasting. Important piece of extra information: the applicable AIC also states that Mode-A+C is no longer allowed. Don't ask me why, I didn't make up these rules. ;) I can't really make any trustworthy remarks about how rigidly these rules are enforced. I haven't really heard of any confirmed situation where somebody was fined over a missing ELT or flying higher than 1200' without a Mode-S transponder. There is one rumour about a plane being refused entry of Dutch airspace coming out of Germany, but I don't know this was indeed about ELT of Mode-S missing. Hope this is of help to you. Marcel PS When will you be visiting Lelystad? From: David Corbett [mailto:david.corbett5@btinternet.com] Sent: donderdag 19 maart 2009 18:58 Subject: Europa-List: Carriage of ELT in Netherlands At a meeting at the UK Civil Aviation Authority on 17 march we were told that carriage of ELT is mandatory for all aircraft in Netherlands airspace. Can our Europa friends in Holland please confirm whether this is the case - I am asking on behalf of a group of UK aircraft, including my Europa, which are going to night stop at Lelystad for 3 nights en route to Norway. And - how rigidly is the carriage of Mode S above 1800' amsl being enforced? Many thanks, David UK 265 - G-BZAM ________________________________ Message 8 _____________________________________ Time: 11:47:24 AM PST US Subject: Re: Europa-List: Garrecht Ultracompact VT01 installed anyone? From: "zwakie" Update: I have it installed and approved now. Complete with all paperwork required. It turned out that the ultracompact could use the normal VT01 paperwork, so costs were saved :wink: Visit - www.EuropaOwners.org ________________________________ Message 9 _____________________________________ Time: 11:48:40 AM PST US Subject: Re: Europa-List: Woodcomp Propellers From: "josok" Dear Frans. For the moment i am still willing to believe you honestly still do not understand what happened and try to fill in the gaps. [quote:e2d9de2b1b] If you throttle back from take-off power to cruise climb, the controller tries to move the blades to the finest pitch possible, and it is the task of the endswitches to prevent the blades from moving even further? [/quote:e2d9de2b1b] Correct. [quote:e2d9de2b1b] With other words, with every throttle move, the blades will always travel to one of the endstops? [/quote:e2d9de2b1b] Of course not, where you did invent that idea now? The controlers task is to keep the rpm as instructed. It will move the blades until that selected rpm is reached. If you would nearly close the throttle it will never reach that rpm, and the fine endstop comes into play to prevent the blades from moving into an unflyable position. Still, even with disabled endstops, due spotwelded contacs, short-circuited diode ect, adding power would increase rpm and the blades would return to a normal pitch. You would never notice what happened. Unless, that underrated pitch motor, which had been struggling hard to turn to negative pitch, now has to struggle again to positive pitch under full load and decides that enough is enough. It burns, blowing the CB. [quote:e2d9de2b1b] If this is the case, I can understand how a failed endstop immediately caused the blades to travel to a non flyable position. [/quote:e2d9de2b1b] No you don't [quote:e2d9de2b1b] As I'm technically handicapped, I picture the working of the prop and controller as follows: Say you fly at 100 knots, and the controller has adjusted the rpm, as you have demanded, to 5000 rpm. Now, if you reduce throttle slightly, the controller reduces the pitch somewhat *without fully traveling to the end stop*, measure the rpm again, evaluate if still below the target rpm, reducing the pitch a little bit more, evaluate again, and stop when the engine again is at 5000 rpm. The end switch has not been used in this scenario, because the prop went never to its finest position in the first place.[/quote:e2d9de2b1b] Correct. [quote:e2d9de2b1b] Even with the end switches shorted, you won't notice anything. Until something else goes wrong... [/quote:e2d9de2b1b] Like closing the throttle a little bit more. [quote:e2d9de2b1b] For a failure, you need an additional factor, something that tries to move the blades to an even finer pitch *while the rpm is already above its target*. [/quote:e2d9de2b1b] No you don't Just closing the throttle is enough to hang you life on the proper functioning of the fine end stop. [quote:e2d9de2b1b] I'm still looking for a scenario where the rpm can rise to 6200 rpm, the blades are in super fine, and something is feeding power to the pitch motor to move the blades even further. What is this "something". Once [/quote:e2d9de2b1b] What about opening the thottle to full power because you are low and slow? [quote:e2d9de2b1b] again: even with all micro-switches shorted, the pitch motor won't run, because power is fed only to these switches if something (the controller, the reverse pitch relay) is sending power to the pitch motor with the purpose of reducing the pitch. The end switches won't see any power, shorted or not, unless something tries to move the pitch motor even further. [/quote:e2d9de2b1b] There is no such thing as a reverse pitch relay. [quote:e2d9de2b1b]It will keep reducing the pitch at any further reducing of throttle, to keep up the RPM. [/quote:e2d9de2b1b] [quote:e2d9de2b1b]Past the desired RPM? [/quote:e2d9de2b1b] Again, stage one: I did explain now how the pitch can turn into fine or negative on any Woodcomp SR 3000 with broken fine endswitches. Stage two: If the pitch moter burns at that critical point, it can't do anything to prevent to go past the desired rpm. [quote:e2d9de2b1b] Let me spell it out: In a normal situation, when powering back from take-off power to cruise power, the end/stops/limit switches never come into play, because the controller cuts the power to the pitch motor long before the fully finest position is reached. [/quote:e2d9de2b1b] Correct, partly. [quote:e2d9de2b1b] In order for the limit switches to show their failure, something has to keep sending power to the prop circuit, now putting all bets on the limit switches to prevent the prop from going past fully fine. Once again: I think it is not common practice to cruise along with the prop in fully fine, so the end switches should never have been exercised. But something tried to move the blades to fully fine, and apparently even past fully fine. [/quote:e2d9de2b1b] You get the picture. Just reducing the power under the power needed for the engine to keep the desired rpm will make the conmtroller send more "fine" power into the pitch motor. [quote:e2d9de2b1b] Now, as I studied the schematics, there are only two power sources for the prop pitch motor: the controller, and the reverse circuitry. One of these circuits had to be inadvertently sending power to the pitch motor, while the rpm was already way up. [/quote:e2d9de2b1b] Wrong, you mixing up stage one, how to get the blades over fine pitch, with stage two, having burnt the pitch motor. The rpm will not go up, will never reach desired rpm unless there is enough power added. Adding power, burning the motor then will overrun the engine. [quote:e2d9de2b1b] By definition, the reverse circuitry has to bypass the microswitches, because its purpose is to intentionally move the blades past fully fine. That makes the reverse circuitry suspect number one. If I then read that you have modified the reverse circuit, it is not difficult to start to wonder if this has had something to do with it. [/quote:e2d9de2b1b] Wrong again. The reverse circuitry uses it's own slipring, and has nothing to do with the fine pitch microswitches. By the way, the diode is there to return power to the pitch motor with opened micro switches. Not intended nor rated for spark killing. [quote:e2d9de2b1b] If I recall correctly: on the Woodcomp there is a third slip ring, for adding power to move the prop beyond its normal flying operating range. This is used for reverse, or feathering. You need to put power on this ring to feather or go to reverse. This third ring is not connected to the controller, so the controller is no longer suspect here. Normally you put power on this third ring with a safety latched switch. It appears from your message that you replaced the function of this switch by a relay. [/quote:e2d9de2b1b] I told you that the reverse circuit was switched off, no power, no relay power, powerless, cold not doing anything, dead, not working, not operating. Safety latched. It's just not possible for circuits to operate without power. Not in this world anyhow. I also explained how the pitch ended up super fine. I also explained why the pitch could not return to normal. Most probably you don't want to understand the facts, it is much easier to cap your ears. Last advice: Find an SR 3000 and have a good look at the components. Google the specifications of those life critical parts. Poor water over these microswitches. Run then pitch motor up and down for an hour or so while restricting the blade movement. But on the ground please! Regards, Jos Okhuijsen Visit - www.EuropaOwners.org ________________________________ Message 10 ____________________________________ Time: 01:48:48 PM PST US From: Frans Veldman Subject: Re: Europa-List: Carriage of ELT in Netherlands David Corbett wrote: > At a meeting at the UK Civil Aviation Authority on 17 march we were told > that carriage of ELT is mandatory for all aircraft in Netherlands airspace. Well, actually I don't know for sure. I still own a Cessna, using it for international flights, and the maintenance guys told me that I don't need an ELT yet, there is still no enforcement of the rules. I believe them, because they are usually eager to sell me stuff if something suddenly becomes mandatory. So, I have no ELT, and as far as I know, none of the airplanes in our hangar do have an ELT. I would just forget about this ELT-thing. > And - how rigidly is the carriage of Mode S above 1800' amsl being enforced? The truth is, there are no mode-S capable ground stations in the Netherlands yet, as far as I know. I doubt that anyone will find out about the lack of mode-S capability. Under the EHHA TMA (half the country) they will ask you to switch off the transponder, because GA-traffic overloads the ground stations. Still though, a mode-S transponder is mandatory, in every CTR and above 1200 foot. There has been a lot of fuss about this; even gliders are required to carry mode-S. On the other hand, I don't know whether there is some attempted enforcement, and what the fines eventually would be. Actually I have never seen any official as long as I fly so I think chances are very low that someone will bother you, especially if you avoid the larger airfields. Personally, I think you'd better upgrade to a mode S transponder. You can wait a little longer, but finally have to buy a mode-S anyway. The maze is closing. Get it done now, and save yourself the ever increasing non mode-S limitations. Just my 2 cents. -- Frans Veldman ________________________________ Message 11 ____________________________________ Time: 02:55:40 PM PST US From: Karl Heindl Subject: RE: Europa-List: Woodcomp Propellers Josok=2C This is a most fascinating thread and I wish it had never happened. What I would lke to ask you is : How much of this is theory and how much is fact ? Was the hub recovered intact or did it burn as well ? In particular I woul d like to know if there really was a motor failure=3B as you know I had two motor failures. And I believe you when you say that the motor cannot turn the blades at high rpm. These are mickey mouse motors designed for the auto motive industry. Jiri claims they are Bosch manufacture=2C but mine (they s ent me 3 different types) all have the name Johnson stamped on it. I believ e this is a Hongkong company producing millions of these things for the car manufacturers. For that reason I will avoid all pitch changes at high rpm and below 2000 f eet. Karl > Subject: Re: Europa-List: Woodcomp Propellers > From: josok-e@ukolo.fi > Date: Thu=2C 19 Mar 2009 20:48:05 +0200 > To: europa-list@matronics.com > > > Dear Frans. > > For the moment i am still willing to believe you honestly still do not un derstand what happened and try to fill in the gaps. > [quote:e2d9de2b1b] > If you throttle back from take-off power to cruise climb=2C the controlle r > tries to move the blades to the finest pitch possible=2C and it is the > task of the endswitches to prevent the blades from moving even further? > [/quote:e2d9de2b1b] > Correct. > [quote:e2d9de2b1b] > With other words=2C with every throttle move=2C the blades will always > travel to one of the endstops? > [/quote:e2d9de2b1b] > Of course not=2C where you did invent that idea now? > > The controlers task is to keep the rpm as instructed. > It will move the blades until that selected rpm is reached. > If you would nearly close the throttle it will never reach that rpm=2C an d the fine endstop comes into play to prevent the blades from moving into a n unflyable position. Still=2C even with disabled endstops=2C due spotwelde d contacs=2C short-circuited diode ect=2C adding power would increase rpm a nd the blades would return to a normal pitch. You would never notice what h appened. Unless=2C that underrated pitch motor=2C which had been struggling hard to turn to negative pitch=2C now has to struggle again to positive pi tch under full load and decides that enough is enough. It burns=2C blowing the CB. > [quote:e2d9de2b1b] > If this is the case=2C I can understand how a failed endstop immediately > caused the blades to travel to a non flyable position. > [/quote:e2d9de2b1b] > No you don't > [quote:e2d9de2b1b] > As I'm technically handicapped=2C I picture the working of the prop and > controller as follows: > Say you fly at 100 knots=2C and the controller has adjusted the rpm=2C as > you have demanded=2C to 5000 rpm. Now=2C if you reduce throttle slightly =2C > the controller reduces the pitch somewhat *without fully traveling to > the end stop*=2C measure the rpm again=2C evaluate if still below the tar get > rpm=2C reducing the pitch a little bit more=2C evaluate again=2C and stop when > the engine again is at 5000 rpm. The end switch has not been used in > this scenario=2C because the prop went never to its finest position in th e > first place.[/quote:e2d9de2b1b] > > Correct. > [quote:e2d9de2b1b] > Even with the end switches shorted=2C you won't notice anything. > > Until something else goes wrong... > [/quote:e2d9de2b1b] > Like closing the throttle a little bit more. > [quote:e2d9de2b1b] > For a failure=2C you need an additional factor=2C something that tries to > move the blades to an even finer pitch *while the rpm is already above > its target*. > [/quote:e2d9de2b1b] > No you don't Just closing the throttle is enough to hang you life on the proper functioning of the fine end stop. > [quote:e2d9de2b1b] > I'm still looking for a scenario where the rpm can rise to 6200 rpm=2C th e > blades are in super fine=2C and something is feeding power to the pitch > motor to move the blades even further. What is this "something". Once > [/quote:e2d9de2b1b] > What about opening the thottle to full power because you are low and slow ? > [quote:e2d9de2b1b] > again: even with all micro-switches shorted=2C the pitch motor won't run =2C > because power is fed only to these switches if something (the > controller=2C the reverse pitch relay) is sending power to the pitch moto r > with the purpose of reducing the pitch. The end switches won't see any > power=2C shorted or not=2C unless something tries to move the pitch motor > even further. > [/quote:e2d9de2b1b] > There is no such thing as a reverse pitch relay. > [quote:e2d9de2b1b]It will keep reducing the pitch at any further > reducing of throttle=2C to keep up the RPM. > [/quote:e2d9de2b1b] > [quote:e2d9de2b1b]Past the desired RPM? > [/quote:e2d9de2b1b] > Again=2C stage one: I did explain now how the pitch can turn into fine or negative on any Woodcomp SR 3000 with broken fine endswitches. > Stage two: If the pitch moter burns at that critical point=2C it can't do anything to prevent to go past the desired rpm. > > [quote:e2d9de2b1b] > Let me spell it out: In a normal situation=2C when powering back from > take-off power to cruise power=2C the end/stops/limit switches never come > into play=2C because the controller cuts the power to the pitch motor lon g > before the fully finest position is reached. > [/quote:e2d9de2b1b] > Correct=2C partly. > [quote:e2d9de2b1b] > In order for the limit switches to show their failure=2C something has to > keep sending power to the prop circuit=2C now putting all bets on the > limit switches to prevent the prop from going past fully fine. Once > again: I think it is not common practice to cruise along with the prop > in fully fine=2C so the end switches should never have been exercised. Bu t > something tried to move the blades to fully fine=2C and apparently even > past fully fine. > [/quote:e2d9de2b1b] > You get the picture. > Just reducing the power under the power needed for the engine to keep the desired rpm will make the conmtroller send more "fine" power into the pitc h motor. > [quote:e2d9de2b1b] > Now=2C as I studied the schematics=2C there are only two power sources fo r > the prop pitch motor: the controller=2C and the reverse circuitry. One of > these circuits had to be inadvertently sending power to the pitch motor =2C > while the rpm was already way up. > [/quote:e2d9de2b1b] > Wrong=2C you mixing up stage one=2C how to get the blades over fine pitch =2C with stage two=2C having burnt the pitch motor. The rpm will not go up =2C will never reach desired rpm unless there is enough power added. Adding power=2C burning the motor then will overrun the engine. > [quote:e2d9de2b1b] > By definition=2C the reverse circuitry has to bypass the microswitches=2C > because its purpose is to intentionally move the blades past fully fine. > That makes the reverse circuitry suspect number one. > If I then read that you have modified the reverse circuit=2C it is not > difficult to start to wonder if this has had something to do with it. > [/quote:e2d9de2b1b] > Wrong again. The reverse circuitry uses it's own slipring=2C and has noth ing to do with the fine pitch microswitches. By the way=2C the diode is the re to return power to the pitch motor with opened micro switches. Not inten ded nor rated for spark killing. > > [quote:e2d9de2b1b] > If I recall correctly: on the Woodcomp there is a third slip ring=2C for > adding power to move the prop beyond its normal flying operating range. > This is used for reverse=2C or feathering. You need to put power on this > ring to feather or go to reverse. > This third ring is not connected to the controller=2C so the controller i s > no longer suspect here. > Normally you put power on this third ring with a safety latched switch. > It appears from your message that you replaced the function of this > switch by a relay. > [/quote:e2d9de2b1b] > I told you that the reverse circuit was switched off=2C no power=2C no re lay power=2C powerless=2C cold not doing anything=2C dead=2C not working=2C not operating. Safety latched. It's just not possible for circuits to oper ate without power. Not in this world anyhow. I also explained how the pitch ended up super fine. I also explained why the pitch could not return to no rmal. Most probably you don't want to understand the facts=2C it is much ea sier to cap your ears. > > Last advice: > Find an SR 3000 and have a good look at the components. Google the specif ications of those life critical parts. Poor water over these microswitches. Run then pitch motor up and down for an hour or so while restricting the b lade movement. But on the ground please! > > Regards=2C > > Jos Okhuijsen > > > > > > > Visit - www.EuropaOwners.org > > > > > =========== =========== =========== =========== > > > ________________________________ Message 12 ____________________________________ Time: 03:29:59 PM PST US From: "ALAN YERLY" Subject: Europa-List: Constant Speed Prop and failure modes. It has been great reading your experiences with the Woodcomp. It is possible for most electric props to put you in a position where a failure in the electrical circuit can cause what they used to call a "runaway prop" situation. The point where the fine pitch stop is reached by the controller or manual settings or a failure of one or both. My experience with the Airmaster prop is being cited here... The fine mechanical stop on the Airmaster is typically 10 degrees of pitch. For a 914 equipped aircraft, this means you can achieve 5800 RPM with very little throttle movement, because the prop is absorbing almost no torque. This can put the aircraft in a position where you are producing insufficient thrust to continue flying in anything but slow flight. This failure is well spelled out in the Airmaster propeller operating handbook. One owner had this malfunction because of a self inflicted switch error by going manual operation thinking he was in automatic operation. He took off and flew. When coming in to land in cruise setting, he reduced the power to idle and the prop controller commanded fine pitch, (The prop will adjust the pitch in auto to try to get the RPM up to the 5000 rpm, the cruise setting commands, which means the prop went to the fine stop). As he approached the field he set the prop controller to Takeoff and inadvertently hit the manual switch. When he added power, the rpm shot to 5800 in a heartbeat. The prop did as commanded, nothing, as it is in manual. Even at 5800 rpm the plane would only barely stay airborne. He luckily set down and called me. We went over the switches and behold he found the problem. If an electric prop controller fails, especially at low altitude, a fine pitch/runaway prop condition puts you in a position, where only your skill and cunning, cool airmanship, and knowledge of your propeller and aircraft can save you and or your plane. (Good Job Frans!) The Airmaster has a dedicated manual control which bypasses everything to give you electric pitch control and a mechanical stop. Propellers, such as the Woodcomp, with Beta (reversing) do not have mechanical stops, only electric. A good manufacturer will insure the prop has a double backup and clear instructions on operations because the prop limit switch or controller failure can cause the prop to go into reverse or bypass an electrical stop, causing an over rev or worst case, reverse thrust in flight. A number of aircraft were lost in the 30's because of runaway props. Consequently reputable manufactures make sure they have manual backups and mechanical stops to prevent aircraft loss. Thanks for your running comments because we all could use a review of our prop manuals. Bud Yerly ________________________________ Message 13 ____________________________________ Time: 06:13:27 PM PST US Subject: Re: Europa-List: Constant Speed Prop and failure modes. From: "josok" Thanks for the clear story Bud, [quote:022a4d2f87]The Airmaster has a dedicated manual control which bypasses everything to give you electric pitch control and a mechanical stop. Propellers, such as the Woodcomp, with Beta (reversing) do not have mechanical stops, only electric. [/quote:022a4d2f87] Just one correction: The SR 3000 does not have mechanical stops, not on any non-reversable or feathering either. [quote:022a4d2f87]A number of aircraft were lost in the 30's because of runaway props. Consequently reputable manufactures make sure they have manual backups and mechanical stops to prevent aircraft loss.[/quote:022a4d2f87] And i might add that manual backup does not help if the pitch motor belongs in a toy car. Regards, Jos Okhuijsen Visit - www.EuropaOwners.org ________________________________ Message 14 ____________________________________ Time: 08:23:09 PM PST US From: Fred Klein Subject: Europa-List: Constant Speed Props, etc. To those who have yet to make a prop-commitment, these new blades Airmaster is testing look like a vast improvement over the Warp Drive blades. Fred Begin forwarded message: > From: "Airmaster Propellers Sales" > Date: March 19, 2009 7:54:38 PM PDT > To: "Fred Klein" > Subject: RE: AP332 blades > > Hi Fred > > It is true we are testing new propeller types. > > For the Europa we are currently in the process of testing a two blade > propeller using Sensenich blades and a three blade propeller using > Kiev > (amounst others) Both are at a diameter of 64in. Each will have > advantages > and disadvantages compared to the Warpdrive. > > I will make results available once I have a good idea of how these new > propellers will perform. > > Regards > Martin > > -----Original Message----- > From: Fred Klein [mailto:fklein@orcasonline.com] > Sent: Friday, March 20, 2009 3:36 PM > To: sales@airmasterpropellers.com > Subject: AP332 blades > > > Some time ago, I heard talk that Airmaster was going to offer an > alternative to the Warp Drive blades...am I correct?...was it just > talk?...what is the current status of such an offering? > > My enquiry is w/ regard to a Europa XS monowheel which necessitates a > rather small diameter propeller. > > Thanks much, > > Fred ________________________________ Message 15 ____________________________________ Time: 09:00:25 PM PST US From: "ALAN YERLY" Subject: Re: Europa-List: Constant Speed Prop and failure modes. Jos, I typed Frans instead of you Jos for the congrats....No excuse...In a rush to another Eagle Scout Board of Review and didn't proof my work. Too many irons in the fire today. Sorry, I was only generally commenting on electric reverse pitch props, and did not intend to segregate the SR3000. Beta control props normally do not have a mechanical fine pitch stop (without a lot of mechanical do dads and overrides) because the prop must go from fine to flat to negative to operate. In my Air Force career I never flew C-130's but did see that they have quite a system of hydro-mechanical and operational restrictions on reverse thrust for safety. A great deal of operational and emergency training covered all the failure modes. I wish our light plane industry did the same. Re reading my post, I did not intend to say any particular prop manufacturer is more reputable than any other. I believe they all try to give the best product they can for a competitive price. Buyer be ware is generally not a factor in aviation, as nearly all manufacturers are sensitive to feedback on their products and their clients safety. As far as the motors in an electric prop, it does amaze me how little power it takes to move the prop blade given the mechanical advantage. During a troubleshooting test, I have run a 7 amp test battery completely flat running the Airmaster from fine to feather and back to test how long it takes for a feathered gliding position to fine pitch power transition and to try and see how quick the prop can respond from the fine stop at 10 degrees min to the normal full power pitch of about 19 degrees (depending on blade length) and the motor never got hot or squawked, and neither did the controller. If you're smooth on the throttle and don't jamb the throttle from idle to full, it keeps pace nicely. For the guys looking for props, especially when they have never flown constant speed props, we need to share our experiences. But for those searching for info, they need to understand the operational and emergency response necessary for the eventual equipment malfunction, then through personal training and emergency procedure training keep their skills up in the event of failure. Of course I'd rather be lucky than good any day, but you can't always trust to luck. Hydraulic props are not without their problems either... But that is another subject for another day. Good night, Bud ----- Original Message ----- From: josok To: europa-list@matronics.com Sent: Thursday, March 19, 2009 9:10 PM Subject: Re: Europa-List: Constant Speed Prop and failure modes. > Thanks for the clear story Bud, [quote:022a4d2f87]The Airmaster has a dedicated manual control which bypasses everything to give you electric pitch control and a mechanical stop. Propellers, such as the Woodcomp, with Beta (reversing) do not have mechanical stops, only electric. [/quote:022a4d2f87] Just one correction: The SR 3000 does not have mechanical stops, not on any non-reversable or feathering either. [quote:022a4d2f87]A number of aircraft were lost in the 30's because of runaway props. Consequently reputable manufactures make sure they have manual backups and mechanical stops to prevent aircraft loss.[/quote:022a4d2f87] And i might add that manual backup does not help if the pitch motor belongs in a toy car. Regards, Jos Okhuijsen Visit - www.EuropaOwners.org http://www.matronics.com/Navigator?Europa-List http://www.matronics.com/contribution ________________________________ Message 16 ____________________________________ Time: 09:21:40 PM PST US From: "ALAN YERLY" Subject: Re: Europa-List: Constant Speed Props, etc. Fred and all, Martin will be sending the new blades to me for test also. I will run a test of the fixed warp drive, standard Airmaster AP332 with Warp drive blades and the new Kiev blades. Probably won't get the two blade for the Europa test, but I can hope. We look to have the two blade on a float plane with longer blades than we use (68"). Look for info to follow, and postings to my website. Should be just after Sun n Fun. in early May... Bud Yerly Custom Flight Creations www.customflightcreations.com ----- Original Message ----- From: Fred Klein To: europa-list@matronics.com Sent: Thursday, March 19, 2009 11:19 PM Subject: Europa-List: Constant Speed Props, etc. To those who have yet to make a prop-commitment, these new blades Airmaster is testing look like a vast improvement over the Warp Drive blades. Fred Begin forwarded message: From: "Airmaster Propellers Sales" > Date: March 19, 2009 7:54:38 PM PDT To: "Fred Klein" > Subject: RE: AP332 blades > Hi Fred It is true we are testing new propeller types. For the Europa we are currently in the process of testing a two blade propeller using Sensenich blades and a three blade propeller using Kiev (amounst others) Both are at a diameter of 64in. Each will have advantages and disadvantages compared to the Warpdrive. I will make results available once I have a good idea of how these new propellers will perform. Regards Martin -----Original Message----- From: Fred Klein [mailto:fklein@orcasonline.com] Sent: Friday, March 20, 2009 3:36 PM To: sales@airmasterpropellers.com Subject: AP332 blades Some time ago, I heard talk that Airmaster was going to offer an alternative to the Warp Drive blades...am I correct?...was it just talk?...what is the current status of such an offering? My enquiry is w/ regard to a Europa XS monowheel which necessitates a rather small diameter propeller. Thanks much, Fred ________________________________ Message 17 ____________________________________ Time: 11:03:40 PM PST US From: Fred Klein Subject: Re: Europa-List: Constant Speed Props, etc. On Mar 19, 2009, at 9:11 PM, ALAN YERLY wrote: > Martin will be sending the new blades to me for test also. I will > run a test of the fixed warp drive, standard Airmaster AP332 with > Warp drive blades and the new Kiev blades. Bud...Do you know whether or not the new blades are compatible w/ the AP332 hub? 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