Seth Posted October 16, 2015 Report Posted October 16, 2015 Hi Seth, Good question. Short answer - no it is not full feathering. Long answer - it was my choice in the end and here is why. Larry Schlasinger who arranged the prop sale and made the Field Approval Application. MT USA, told me he could arrange the field approval for the full feathering prop just like their STC 4 blade for the Cessna 340 - matching the source of my rocket engine STC. But he convinced me to think twice about a full feathering prop on a single engine airplane. There is a failure mode I had never considered, which is the prop governor can go bad - at full power take off, and then it could go to full feather - then even though the engine is running full power you loose all thrust - at the most vulnerable moment - upon take off. A standard prop governor can't do that and if it fails it still has pitch to make thrust. I had never considered that before! On the other hand, then you loose the superb glide of full feathering if you loose engine in cruise - something I always felt great about. He convinced me that if you can stop the prop from windmilling, then you get back a large fraction of that same glide ratio. He says he has test that numerous times - to test it you actually need to shut the engine off in flight, not just idle thrust - not for me. Anyway, I went with this argument since I decided that yes, the risk on take off problem is more important than a risk in cruise - which can be somewhat mitigated by stopping the prop. (How to do that - a discussion for another day - will I be successful to do so if it ever happens to me - I hope so - its an easy procedure in theory). Besides that - and less important than the safety discussion above: the prop and governor I got saved 30lbs. The full feathering version saved only 10lbs, and remember it was trying to save weight off the nose that got me started on this project. Also the full feathering was $3k more, but again that was not the deciding factor. That said if you go with the MT, there is no STC for a rocket conversion yet so it would be by field approval and go for which every you want. Thanks for the info Erik. That's good information about at potential prop governor failure. I'm calling today to ensure I know the failure mode in the Missile. I always thought it would go to the top RPM, not feather (full power), but that may not be the case as I'm sure the system on my aircraft is very similar to yours. Were the posted pictures before or after the spinner spacer issue was resolved? I know you had an issue with the first install. The four blades look fantastic. I will report back. The lighter weight on our Rocket and Missile airframes up from must make a HUGE difference in both feel and high speed cruise. Let me know when you're in Maryland - I'll shoot you a PM or email for coordination. Maybe we'll schedule a Mooney lunch/get together/NJ group (really Mid Atlantic) while you are out here or on the way home. -Seth 1 Quote
carusoam Posted October 16, 2015 Report Posted October 16, 2015 (edited) Seth, It would be real important to know... The only governor failure I had was on departure. The plug at the end of the crankshaft dislodged and leaked oil pressure internally. The O360 govenor failed and went to max rpm... In your case, I would expect the failure to go max prop feathering. Be extra attentive during the run-up. If the run-up doesn't seem right, taking it into the air isn't going to make it any better. Real life experience from my M20C, -a- Edited October 16, 2015 by carusoam 1 Quote
Houman Posted October 16, 2015 Report Posted October 16, 2015 Seth, It would be real important to know... The only governor failure I had was on departure. The plug at the end of the crankshaft dislodged and leaked oil pressure internally. The O360 govenor failed and went to max rpm... In your case, I would expect the failure to go max prop feathering. Be extra attentive during the run-up. If the run-up doesn't seem right, taking it into the air isn't going to make it any better. Real life experience from my M20C, -a- How would one know if a governor failure was imminent, what are the signs to look for on runup ?. I have the Full feathering prop on the Rocket, so just wondering. Thanks ! Quote
carusoam Posted October 16, 2015 Report Posted October 16, 2015 (edited) On mine when you set the RPM for run-up,(three times) it didn't behave properly. This may lead a young knowledgable person to think, higher power would help clear things out. Similar to clearing out a bad plug. With the standard mode of failure you will get off the ground OK, but risk overspeeding the prop. The overspeed risk will keep you from flying anywhere. With the Rocket and Missile, the failure, going to partial or to full feather will keep you from climbing... The govenor has it's own oil gear pump to pressurize the crank that twists the blades. Losing the oil pressure in the crank, the blades return to their low pressure state. This state is selected by the engineers. Auto feathering is really good for twins. Full feathering is pretty good for singles. Take-off power and distance can't afford any feathering, usually. Briefly, make sure the run-up rpm is set and stays set. Don't rush through the motions of just refreshing the oil in the system. Pay attention to how long it takes from pulling on the blue knob vs getting the rpm drop. The first time you pull the knob, the crank is empty. The second and third time the crank should be full, the response should be near immediate. I am only a PP. Not a mechanic. Best regards, -a- Edited October 16, 2015 by carusoam Quote
aviatoreb Posted October 17, 2015 Report Posted October 17, 2015 How would one know if a governor failure was imminent, what are the signs to look for on runup ?. I have the Full feathering prop on the Rocket, so just wondering. Thanks ! I didn' t mean to scare everyone. But the test pilot at MT told me that he was surprised that the FAA ever allowed a full feathering prop on a single engine. Up until then I was in blissful love with my my full feathering prop for the superb glide ratio. Seriously though, if I had never talked to him, I bet I would have never known or cared or worried and nothing would have ever happened. But presented with the choice, I chose no full feather. And now, if the other bad thing happens - total loss of power - then stop the prop. Quote
aviatoreb Posted October 17, 2015 Report Posted October 17, 2015 Thanks for the info Erik. That's good information about at potential prop governor failure. I'm calling today to ensure I know the failure mode in the Missile. I always thought it would go to the top RPM, not feather (full power), but that may not be the case as I'm sure the system on my aircraft is very similar to yours. Were the posted pictures before or after the spinner spacer issue was resolved? I know you had an issue with the first install. The four blades look fantastic. I will report back. The lighter weight on our Rocket and Missile airframes up from must make a HUGE difference in both feel and high speed cruise. Let me know when you're in Maryland - I'll shoot you a PM or email for coordination. Maybe we'll schedule a Mooney lunch/get together/NJ group (really Mid Atlantic) while you are out here or on the way home. -Seth What is in those recent pictures is my recent final prop. If you are looking at pictures with the deep nickel leading edge option - then its the new prop. The loaner prop I had temporarily with the too wild gap (like 5'') had the much less pronounced less protective standard stainless steel leading edge. I was going to maybe go to Maryland tomorrow - for my sisters baby shower, but they are forecasting wintry mix here in the am, and I won't brave that even with my tks. Wintry mix! Its been such a luscious - warm - colorful autumn and suddenly - wintry mix! Just until noon.... BUT my sister is due to have her baby in November - and you know I am going to go visit the little'n - in Maryland. I'll drop a holler. BUT remember - a mid atlantic/NJ group fly in would be fun - never been to one - but remember I suggested it should be at Rhibeck museum next! Cheers,Erik Quote
aviatoreb Posted October 17, 2015 Report Posted October 17, 2015 I'm in... let me know when !!! You know Houman and Yves....my trip to MD this weekend is canceled - and this Sunday is looking like nice weather..... You guys free? Quote
Yooper Rocketman Posted October 17, 2015 Report Posted October 17, 2015 Hey Erik, Just stumbled on this thread. My project takes up a lot of my free time. Anyway, looks really nice. I will be watching for your reports as you get more time on it. On the prop governors and the full feather going to "full feather" during failure, I have a buddy with a Comanche (I think the 400) that had a governor failure during cruise flight and his failure mode put the prop to flat. He had all he could do to keep the RPM below red line while giving up 300' a minute all the way to the ground. He was able to find a small remote airport to land on, but almost ended up on a US highway. Doc can probably elaborate on this, as I am not a prop governor guru, but prop governor failures can be bad in any flight condition, not just climb. Tom 1 Quote
Houman Posted October 17, 2015 Report Posted October 17, 2015 Hi Erik, I'm free tomorrow ( saturday ), but sunday I have my mecanic installing my AOA and Reiff Heater on sunday all day. My mecanic is not free tomorrow, but if it is good enough weather, I can come no problem. Quote
aviatoreb Posted October 17, 2015 Report Posted October 17, 2015 Hi Erik, I'm free tomorrow ( saturday ), but sunday I have my mecanic installing my AOA and Reiff Heater on sunday all day. My mecanic is not free tomorrow, but if it is good enough weather, I can come no problem. Weather is crummy tomorrow morning - and tomorrow afternoon - my wife already has alternate plans for me booked.... Quote
Guest Posted October 17, 2015 Report Posted October 17, 2015 Here is a Cirrus SR22 with the four blade MT. Quote
Houman Posted October 17, 2015 Report Posted October 17, 2015 Nah, Erik''s Rocket looks much better than this little bird with 4 blade prop 2 Quote
Hank Posted October 17, 2015 Report Posted October 17, 2015 Nah, Erik''s Rocket looks much better than this little bird with 4 blade prop Wish I could "like" this post more than once . . . 1 Quote
aviatoreb Posted October 17, 2015 Report Posted October 17, 2015 Here is a Cirrus SR22 with the four blade MT. I would have thought the blades would be identical, but mine appear thicker. I have the nickel leading edge - which is a much deeper covering sheath - than this blade set that has the much less pronounced steel leading edge. Oh yeah - Mooney Rocket looks better with 4 blade - cuz yah know - its a Mooney! 2 Quote
Seth Posted October 20, 2015 Report Posted October 20, 2015 I didn' t mean to scare everyone. But the test pilot at MT told me that he was surprised that the FAA ever allowed a full feathering prop on a single engine. Up until then I was in blissful love with my my full feathering prop for the superb glide ratio. Seriously though, if I had never talked to him, I bet I would have never known or cared or worried and nothing would have ever happened. But presented with the choice, I chose no full feather. And now, if the other bad thing happens - total loss of power - then stop the prop. I went ahead and confirmed this. If the prop governor goes, the prop will feather on both Mooney Missiles and Mooney Rockets. It took multiple prop shops to confirm this and once I gave the actual serial number and model number of my prop governor, that's when I got the confirmed information. So my question is can the governor be replaced with one that the failure mode is high RPM yet I can still then manually feather the prop? I'll start a new thread. Erik - your prop looks AWESOME. The pictures on the first page of this threat just look fantastic. -Seth 1 Quote
bonal Posted October 20, 2015 Report Posted October 20, 2015 Wish I could "like" this post more than once . . . I went ahead and gave it I like for you Hank, but I like as well. Still waiting to see the feature video with surround sound from start up to run up ending with a dramatic low high speed pass oops I mean missed approach. 1 Quote
aviatoreb Posted October 20, 2015 Report Posted October 20, 2015 I went ahead and gave it I like for you Hank, but I like as well. Still waiting to see the feature video with surround sound from start up to run up ending with a dramatic low high speed pass oops I mean missed approach. I liked your like. I invited my Canadian friends last weekend - and no reply.... :-O I thought if I got a pretty fancy cool prop that I would have more friends. Oh well. At least I go fast and I look good doing it. Quote
aviatoreb Posted October 20, 2015 Report Posted October 20, 2015 I went ahead and confirmed this. If the prop governor goes, the prop will feather on both Mooney Missiles and Mooney Rockets. It took multiple prop shops to confirm this and once I gave the actual serial number and model number of my prop governor, that's when I got the confirmed information. So my question is can the governor be replaced with one that the failure mode is high RPM yet I can still then manually feather the prop? I'll start a new thread. Erik - your prop looks AWESOME. The pictures on the first page of this threat just look fantastic. -Seth I replied to the other thread. I'm sorry I buggered all my rocket-missile friends! Quote
Hank Posted October 20, 2015 Report Posted October 20, 2015 I liked your like. I invited my Canadian friends last weekend - and no reply.... :-O I thought if I got a pretty fancy cool prop that I would have more friends. Oh well. At least I go fast and I look good doing it. Huh . . . I saw his reply here somewhere. One of you was available Saturday, the other Sunday, but I don't recall who was who, nor which thread it was in. Scroll back and check, Houman wasn't it? Bring that fancy prop down here and I'll help attract a crowd to please ya! Quote
carusoam Posted October 20, 2015 Report Posted October 20, 2015 Either failure is problematic... 1) Featheringing below 1,000' means land straight ahead... Cause: gov. Sys. Failure. 2) Not feathering below 1,000' means land straight ahead... Cause engine failure. 3) feathering above 10,000' means glide 20% further than the other guy.... 4) Not feathering above 10,000’ means that when you pull the blue knob you will glide further, unless you stop the prop's rotation. That would be even better.... Neither system is perfect. The pilot really needs to know what system he has to properly build a complete portfolio of Plan Bs... with all the Mooney failures we have had over the years we have several engine stoppages and very few govenor failures. Of course, an ordinary gov failure isn't very memorable. The one gov failure I have experienced was detectable on run-up. A clear don't fly when you know what govenor you have. Another consideration for TakAir's linear actuator in Mooney aviation. The old oil gear pump technology was good in it's day. A simple hose fitting can cause a problem. My M20C lost it's internal crank seal. Internal leaks are really tough to see. Pay attention to exact settings of rpm while doing the run-up, don't just go through the motions quickly, -a- Quote
aviatoreb Posted October 20, 2015 Report Posted October 20, 2015 Huh . . . I saw his reply here somewhere. One of you was available Saturday, the other Sunday, but I don't recall who was who, nor which thread it was in. Scroll back and check, Houman wasn't it? Bring that fancy prop down here and I'll help attract a crowd to please ya! That was my other Canadian friend (actually I have many Canadian friends - but I meant nearby Mooney Canadian friend) Houman who we couldn't get together. It was Yves who volunteered to do filming and we seemed to have missed each other so far. Where are you Hank? Quote
aviatoreb Posted October 20, 2015 Report Posted October 20, 2015 Either failure is problematic... 1) Featheringing below 1,000' means land straight ahead... Cause: gov. Sys. Failure. 2) Not feathering below 1,000' means land straight ahead... Cause engine failure. 3) feathering above 10,000' means glide 20% further than the other guy.... 4) Not feathering above 10,000’ means that when you pull the blue knob you will glide further, unless you stop the prop's rotation. That would be even better.... Neither system is perfect. The pilot really needs to know what system he has to properly build a complete portfolio of Plan Bs... with all the Mooney failures we have had over the years we have several engine stoppages and very few govenor failures. Of course, an ordinary gov failure isn't very memorable. The one gov failure I have experienced was detectable on run-up. A clear don't fly when you know what govenor you have. Another consideration for TakAir's linear actuator in Mooney aviation. The old oil gear pump technology was good in it's day. A simple hose fitting can cause a problem. My M20C lost it's internal crank seal. Internal leaks are really tough to see. Pay attention to exact settings of rpm while doing the run-up, don't just go through the motions quickly, -a- That's pretty much it. As I said, I was in bliss with no idea of the danger that lurked in possible governor failure, and I loved loved the concept of the full feathering prop extending glide range. As you can see - I concluded the danger of a failure at low altitude was more serious than a failure at cruise altitude since the most vulnerable time in any flight is during take off at low altitude when low, slow and not lots of landing site options. Stopping the prop is something that is supposed to really improve glide rage, but there is a danger there too. You need to slow the plane well below Vg briefly, close to stall - and the question is do you trust yourself to do that and not make things worse in the heat of the moment, just after an engine failure. Certainly plenty of engine failures have preceded the pilot then getting too slow and then stall then spin. So if stopping the prop will be the course of action, it must be done meticulously. Quote
aviatoreb Posted October 20, 2015 Report Posted October 20, 2015 Of course, an ordinary gov failure isn't very memorable. The one gov failure I have experienced was detectable on run-up. A clear don't fly when you know what govenor you have. I think thats it. They do fail now and then. Just that it is generally not catastrophic - just annoying. I know of two that have failed. One on a friends M20C and he made an uneventful landing. The other at a nearby airport I heard a guy on the radio announce that he had a prop governor failure and that he was making an emergency landing, which is what he did, and we gave him priority. Again uneventful. No ntsb. Quote
Hank Posted October 20, 2015 Report Posted October 20, 2015 That was my other Canadian friend (actually I have many Canadian friends - but I meant nearby Mooney Canadian friend) Houman who we couldn't get together. It was Yves who volunteered to do filming and we seemed to have missed each other so far. Where are you Hank? Sorry, Erik, the temptation is too great . . . (cue the music!) My home's in Alabama, Southern born and Southern bred. Quote
aviatoreb Posted October 20, 2015 Report Posted October 20, 2015 Sorry, Erik, the temptation is too great . . . (cue the music!) My home's in Alabama, Southern born and Southern bred. Is that near Toronto? 1 Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.