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RE: PCM Lockout question
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Raf,
I was flying my Simjet 300 powered SpiderJets F-16 during an extremely cold jet meeting here in Norway this winter. I was setting up for a landing because I was freezing my nails off, at the same time a friend of mine landed his Merlin powered Eurofighter and taxied by me. With the noise from his turbine, I was unaware of the fact that I had a flameout on finals, and proceeded like I had a running turbine with 25-30% power. The plane just came to a complete stop in the air approx. 50 feet up, and fell straight to the ground with the wheels out. The "landing" caused the wheels, legs, retracts and formers to brake off, and the flex in this moment caused the plane to bounce maybe 15 feet up again. The amazing thing was that there was very little structural damage to the plane, and all internal components were completely unharmed. I had almost 1 litre of fuel left, and the weight during the crash would have been about 13 kg. We are talking about a serious impact here, but the fact that it pancaked on the runway and the wheels, legs and retract formers broke away propably saved it! Afterwards, I was thinking about my failsafe settings and wondering whether to set it to turbine idle, wheels out and full up elevator to try and reduce speed and hope for a loop or two and a pancake crash instead of the rather optimistic slight elevator, slight turn hoping that the plane would land itself if control is lost. After all, if you loose control and the plane goes up in a tight loop. it would be much easier to regain control than if you snaproll it. Here are a couple of pictures - a flyby and falling out of the sky! Notice the elevators going down!! Heard of the bent stick??!!:D |
RE: PCM Lockout question
ORIGINAL: ravill Lee, When you saw that airplane snap to the ground, it sounds like you think a parachute would have saved it. Is this true? Did it slow down enough that a parachute would likely slow it's descend to earth vs tearing the model to shreds because of the high speed? Thanks for sharing!! I also am a futaba guy! Raf Actually at that point in time I had not given a thought to a parachute system. I am willing to accept the total destruction of a model aircraft, long before I want to even think about the nightmare of actually hitting someone on the ground. As to how a parachute system would actually work... I could only envision the engine first being shutdown.. then deployment of the chute. Bungee cord or stretchable chute attach lines might soften the canopy opening enough to not tear loose the lines or break the airplane. The actual details & design would have to be worked out. The parachute idea is a reality in the Full Scale world.... so I see no reason it wouldn't work for us. I am actually both a JR & Futaba fellow.... I fly JR in many aircraft, but since day one of the 10X (I bought one of the first out) I discovered the flaw in programming. You see, if you set the 10X to talk to a Z-mode receiver i.e. the older 512bit type, the fail-safe screen has a user selectable time delay feature.... but when you set the 10X to communicate with the new S-mode receivers.... the time delay feature disappears! Nothing but a software screw up from day one.... but JR has been unwilling to offer an update all these years. Even a user paid call back option would be OK.... but nothing! Lee H. DeMary AMA 36099 |
RE: PCM Lockout question
ORIGINAL: Silver182 A requirement of the radio is that it's software will allow a 1 second delay or HOLD condition before going to the snap-roll condition. JR's earlier 10 channel radios had a fail-safe feature that would allow the user to set the time delay before surface activation. The later 10X radio transmitting to an S-mode receiver does not have a delay feature. In fact there is NO time delay before activation. Can you see why no one with this type radio wants to hear anything about fail-safe settings other than HOLD... ... As I have mentioned several times before the reason the turbine manufactures have a time delay feature within the ECU is to allow a shutdown fail-safe setting required by AMA for turbine use! Yep, the most widely used radio the JR 10X would not be usable.... in the turbine world if the turbine ECU did not have the time delay feature included within it's software. Lee H. DeMary AMA 36099 The 1 s delay in the radio is there to allow for short duration interference. The Rx applies a hold setting until the interference either dissapears, or if more than 1 second has elapsed applies the pre-determined fail-safe settings. The 1s delay in the ECU doesn't solve the problem of the missing delay in later JR 10X radios operating in S mode. /Red B. |
RE: PCM Lockout question
Wow Ice,
Nice pics, sorry about your bird, although nice save on your electronics and turbine!! I am wondering about the speed that a jet would attain in the event of a snap roll lockout. I am pondering new ideas!! Raf |
RE: PCM Lockout question
Lee,
Thanks for your input on your thoughts regarding the speed of the airplane. Thinking back now, do you think a parachute would have saved some parts of that jet? I'm with you, I'd rather loose my jet than even risk having my jet be uncontrollable. thanks again, Raf |
RE: PCM Lockout question
ORIGINAL: Red B. ORIGINAL: Silver182 A requirement of the radio is that it's software will allow a 1 second delay or HOLD condition before going to the snap-roll condition. JR's earlier 10 channel radios had a fail-safe feature that would allow the user to set the time delay before surface activation. The later 10X radio transmitting to an S-mode receiver does not have a delay feature. In fact there is NO time delay before activation. Can you see why no one with this type radio wants to hear anything about fail-safe settings other than HOLD... ... As I have mentioned several times before the reason the turbine manufactures have a time delay feature within the ECU is to allow a shutdown fail-safe setting required by AMA for turbine use! Yep, the most widely used radio the JR 10X would not be usable.... in the turbine world if the turbine ECU did not have the time delay feature included within it's software. Lee H. DeMary AMA 36099 The 1 s delay in the radio is there to allow for short duration interference. The Rx applies a hold setting until the interference either dissapears, or if more than 1 second has elapsed applies the pre-determined fail-safe settings. The 1s delay in the ECU doesn't solve the problem of the missing delay in later JR 10X radios operating in S mode. /Red B. I hope everyone understands the reason for PCM in the first place..PCM encoding provides a hold time so all of the little short duration.. 1/8 second 1/4 second...1/2 second glitches are never seen by the pilot. If the turbine manufactures had not come up with a time delay system within their ECU's... no one would be flying the JR 10X especially when flying a turbine powered aircraft! It is mandatory here in the States to use a radio capable of providing fail-safe shutdown. We have a mandatory 2 second Max time delay before shutdown per AMA. Turbine shutdown is required during a R/F link failure. No time delay would equal flame-outs all the time! Red, your sorta correct... except that the time allowed by your turbine ECU... Example the JetCat ECU can be set for any amount of time delay before the turbine actually shuts-down! Anywhere from 1 second to 10 or more seconds! The turbine ECU time delay solves the JR 10X no time delay problem for throttle channel only. Of course it doesn't solve the problem for the remaining channels. The 10X fail-safe is all but un-useable on any channel other than throttle! The 10X does not have a hold time delay so all short duration interference is seen by the pilot just like a glitch of yesterday... that is if fail-safe presets are used. That is the reason very few if any pilots flying the 10X will ever preset fail-safe GO-TO settings! All flight surfaces are usually set for HOLD only.. JR has known about this programming Error for many years as I have told them about it for several years... they just don't care to fix the problem. Lee H. DeMary AMA 36099 |
RE: PCM Lockout question
ORIGINAL: Silver182 It is mandatory here in the States to use a radio capable of providing fail-safe shutdown. We have a mandatory 2 second Max time delay before shutdown per AMA. Turbine shutdown is required during a R/F link failure. No time delay would equal flame-outs all the time! /Red B. |
RE: PCM Lockout question
ORIGINAL: icepilot Raf, I was flying my Simjet 300 powered SpiderJets F-16 during an extremely cold jet meeting here in Norway this winter. I was setting up for a landing because I was freezing my nails off, at the same time a friend of mine landed his Merlin powered Eurofighter and taxied by me. With the noise from his turbine, I was unaware of the fact that I had a flameout on finals, and proceeded like I had a running turbine with 25-30% power. The plane just came to a complete stop in the air approx. 50 feet up, and fell straight to the ground with the wheels out. The "landing" caused the wheels, legs, retracts and formers to brake off, and the flex in this moment caused the plane to bounce maybe 15 feet up again. The amazing thing was that there was very little structural damage to the plane, and all internal components were completely unharmed. I had almost 1 litre of fuel left, and the weight during the crash would have been about 13 kg. We are talking about a serious impact here, but the fact that it pancaked on the runway and the wheels, legs and retract formers broke away propably saved it! Afterwards, I was thinking about my failsafe settings and wondering whether to set it to turbine idle, wheels out and full up elevator to try and reduce speed and hope for a loop or two and a pancake crash instead of the rather optimistic slight elevator, slight turn hoping that the plane would land itself if control is lost. After all, if you loose control and the plane goes up in a tight loop. it would be much easier to regain control than if you snaproll it. Here are a couple of pictures - a flyby and falling out of the sky! Notice the elevators going down!! Heard of the bent stick??!!:D The snap-roll setting is one designed to get the airplane out of the air ASAP when a total R/F link failure occurs... and that's the one that can never be predicted. Icepilot go take a look at the video of the airshow crash a few day ago.. RCU sticky thread "Safety Matters" you'll then better understand why in my opinion at this time we only have one choice for the safest fail-safe setup.... the snap-roll. A parachute fail-safe is only a dream.... one that might be safer for airplane & people at the same time. Lee H. DeMary AMA 36099 |
RE: PCM Lockout question
Lee - I do absolutely NOT disagree with your feelings on this - maybe I wasn't clear enough in my post: What I meant was that most people DO set their failsafe to Hold or a "try-to-save-the-plane"-setting, which is an instinctive thought, but not a very clever one. My suggestion about the loop was that I felt that a snaproll without any further control by the pilot would possibly bring the plane out of its axis, while a very tight loop would perhaps keep the plane in line and at the same time bleed off speed rapidly. This is nothing I have tried, just a suggestion.
I have seen the video and let it be very clear: Ditch the plane before even putting the audience at the slightest danger!! We had a crazy guy here in Norway 2 years ago who sabotaged a scale meeting with military radio equipment, and crashed 7 planes including a jet at top speed. He was caught, put in jail for a period of time and very heavily fined and his equipment was confiscated - in my opinion he should have been charged with attempted murder. So yes, we know and respect the rules: Life and health before money and models.... Tor |
RE: PCM Lockout question
ORIGINAL: icepilot Lee - I do absolutely NOT disagree with your feelings on this - maybe I wasn't clear enough in my post: What I meant was that most people DO set their failsafe to Hold or a "try-to-save-the-plane"-setting, which is an instinctive thought, but not a very clever one. My suggestion about the loop was that I felt that a snaproll without any further control by the pilot would possibly bring the plane out of its axis, while a very tight loop would perhaps keep the plane in line and at the same time bleed off speed rapidly. This is nothing I have tried, just a suggestion. I have seen the video and let it be very clear: Ditch the plane before even putting the audience at the slightest danger!! We had a crazy guy here in Norway 2 years ago who sabotaged a scale meeting with military radio equipment, and crashed 7 planes including a jet at top speed. He was caught, put in jail for a period of time and very heavily fined and his equipment was confiscated - in my opinion he should have been charged with attempted murder. So yes, we know and respect the rules: Life and health before money and models.... Tor To Not disagree.. is to agree... better to just say you agree..English is a straight forward language. Anyway your idea on the looping would work, the only problem I could see with it is that the airplane still wouldn't stop flying As-soon-as-possible! Keep in mind ASAP is what you and I will want when we loose all control. For an exercise lets picture your continuous looping, and engine shutdown in the recent Hungarian accident. Yep, maybe in that case your idea would have worked, unless the crosswind was very strong.. which was mentioned. Someone even believed the wind direction was what caused the biplane to make the turn toward the crowd. The bottom line is as you confirm... we shouldn't be concerned with our model 1st..People first... all else second. Lee H. DeMary AMA 36099 |
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