Raytol Posted October 7, 2018 Posted October 7, 2018 Problem easily fixed by fitting one or two small vertical surfaces to the rear of the fuselage. They have done the same fix to heaps of aircraft in the past.
djpacro Posted October 7, 2018 Posted October 7, 2018 This is taken from Darrol Stinton's book "The Design of the Aeroplane" which might be of relevance or interest. Furthermore Stinton notes that spin damping is better when there is a deep rear fuselage and when there is rudder area beneath the tailplane and elevator. None of these are designed into many modern aircraft including the above as so many LSA type aircraft become very thin towards the real fuselage including this aircraft. Interestingly Stinton (perhaps controversially) writes in relation to the above quote "much of this design wisdom is being lost". Yep, Cessna designers "lost it" for the Skycatcher at first. I have run numbers on quite a few aeroplanes using that method and, as it says here, it is quite good to use in preliminary design. The report detail is at http://naca.central.cranfield.ac.uk/reports/arc/cp/0195.pdf The NACA Tail Damping Power Factor is more simple but not as good as a predictor https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930082166.pdf 1
Blueadventures Posted October 7, 2018 Posted October 7, 2018 It is not the only aeroplane around with those instructions - the early Robin 2160 is another however the Robin has a very big rudder but when they went for American certification the FAA insisted on PARE to stop the spin per FAR 23.I'm certainly interested in seeing the spin test report for the Bristell. Even for types which are not approved for intentional spins the scope of testing is quite comprehensive. Similar type to the Bristell: [ATTACH]62073[/ATTACH][ATTACH]62074[/ATTACH] Abosurely agree, and regardless of the thoroughness when compiled it would be worthwhile revisiting some more testing or re verification of the pilots notes. Need to identify if the aircraft is a primary contributing factor. I have a friend with one of these and he is interested about these matters. Cheers 1
Jabiru7252 Posted October 7, 2018 Posted October 7, 2018 Well, the spin recovery is the same as what I was taught in the Tomahawk years ago.
Mike Borgelt Posted October 7, 2018 Posted October 7, 2018 Take a look at the strakes on the fuselage ahead of the tailplane on the DHC1 Chipmunk. These are also fitted to some Tiger Moths. I think the idea is that at high angles of attack like in a spin, there is a vortex generated by each of them which energises the airflow over the fin and rudder. I knew a bloke (cropduster pilot, now deceased after his last accident) once who spun a Tiger Moth into the ground and lived to tell the tale. The gliding club was hiring it as a towplane. He rented it to do a session of aerobatics and during this noted that it seemed a little reluctant to recover from a spin one way. The other way was fine. Told LAME, who checked the rigging. Next weekend flew it again. One way spin recovery was fine. The other way seemed a little reluctant still. Tried again and it kept spinning all the way into the ground. He turned off the fuel and ignition and tightened his harness and although injured, lived to fly again. Also knew a couple of blokes who were messing about in a Puchacz sailplane and got into a spin at 3500 feet and it would not recover. They were both highest level GFA instructors. Eventually for no known reason it came out and the recovery went down to 350 feet AGL. Lesson is, yes you possibly need spin recovery training fairly early in flight training. Do it in a Pitts or Decathlon, wear parachutes, go to 10,000 over the water or an unpopulated area and if it is still spinning at 5000 feet and you've tried all you can to recover, bail out. Remember the lesson anyway, mentally rehearse it often and NEVER spin accidently because as facthunter says, if you do it accidently it will likely be at low altitude where knowing how to recover will not help. If you are a GFA member you are now required to do spins on every annual check. I consider this a gross intrusion on your personal right to voluntarily select your level of risk exposure. BTW there does not seem to be any evidence that spin training or lack thereof has any effect on the accidental spin in rate. Canada had a PPL spin training requirement for years after the USA abandoned it in 1947 I think. Early in the 21st century Canada did the same after a review of the accident stats showed no difference EXCEPT that the Canadians were losing pilots and instructors in spin training. This was written up in Avweb at the time. 1 2
Roundsounds Posted October 8, 2018 Posted October 8, 2018 Take a look at the strakes on the fuselage ahead of the tailplane on the DHC1 Chipmunk. These are also fitted to some Tiger Moths. I think the idea is that at high angles of attack like in a spin, there is a vortex generated by each of them which energises the airflow over the fin and rudder.I knew a bloke (cropduster pilot, now deceased after his last accident) once who spun a Tiger Moth into the ground and lived to tell the tale. The gliding club was hiring it as a towplane. He rented it to do a session of aerobatics and during this noted that it seemed a little reluctant to recover from a spin one way. The other way was fine. Told LAME, who checked the rigging. Next weekend flew it again. One way spin recovery was fine. The other way seemed a little reluctant still. Tried again and it kept spinning all the way into the ground. He turned off the fuel and ignition and tightened his harness and although injured, lived to fly again. Also knew a couple of blokes who were messing about in a Puchacz sailplane and got into a spin at 3500 feet and it would not recover. They were both highest level GFA instructors. Eventually for no known reason it came out and the recovery went down to 350 feet AGL. Lesson is, yes you possibly need spin recovery training fairly early in flight training. Do it in a Pitts or Decathlon, wear parachutes, go to 10,000 over the water or an unpopulated area and if it is still spinning at 5000 feet and you've tried all you can to recover, bail out. Remember the lesson anyway, mentally rehearse it often and NEVER spin accidently because as facthunter says, if you do it accidently it will likely be at low altitude where knowing how to recover will not help. If you are a GFA member you are now required to do spins on every annual check. I consider this a gross intrusion on your personal right to voluntarily select your level of risk exposure. BTW there does not seem to be any evidence that spin training or lack thereof has any effect on the accidental spin in rate. Canada had a PPL spin training requirement for years after the USA abandoned it in 1947 I think. Early in the 21st century Canada did the same after a review of the accident stats showed no difference EXCEPT that the Canadians were losing pilots and instructors in spin training. This was written up in Avweb at the time. The spin strakes and wide chord rudder on the DHC-1 were proven to have next to no effect on the spin. DeHavilland produced a TNS (effectively an AD) providing operators with information on spinning the Chippy. This was produced not long after the aircraft was put on the Australian register and a few of them spun in. An Australian registered aircraft was extensively tested (VH-RSV, which was also registered as CBM, AFG, WAU and ZIT at various times in its life). Bottom line was, start at a safe height, use the manufacturers recovery technique and you’ll be safe.
djpacro Posted October 8, 2018 Posted October 8, 2018 The spin strakes and wide chord rudder on the DHC-1 were proven to have next to no effect on the spin. Aaah the good old days when CASA's predecessor had the knowledge and interest in our safety wrt spins. 1
poteroo Posted October 8, 2018 Posted October 8, 2018 Most U/L pilots spend a lot of time at circuit height and you can't recover a spin from that position even if you are the Ace of the Base. The inclination to pull back on the stick when the ground is coming up is strong Agree. It especially applies with the 'base-to-final' skidding turn. I'm a believer in training students to fly 'in balance' through each and every phase of flight. An aircraft isn't going to spin, (especially 'under'), if it simply stalls while in balance. As instructors, we are failing our safety duty if we can't produce pilots who fly with both feet and hands. And, (as Nev points out, above),it's much, much higher risk to lose control at low level. On that subject, I don't start any low level training until the pilot can vigorously manoeuvre the aircraft at lower speeds, in all configurations, and recover from incipient stalling with minimal height loss or drama. I'd go further on this, to state that IMHO, the industry problem with accidents due to R-LOC is due in great part to pilot inability to control and manoeuvre the aircraft close to the ground, which is itself in part due to the 'ground-rush' effect as mentioned by Nev (above). happy days, 1
Roundsounds Posted October 8, 2018 Posted October 8, 2018 [ATTACH]62086[/ATTACH]Aaah the good old days when CASA's predecessor had the knowledge and interest in our safety wrt spins. Yes, it gives great peace of mind knowing this extensive testing has been done. I’ve done a lot of spin training in Chippies over the years. I always provide students with a copy of the TNS well before we fly. We then take some time to discuss the published entry, maintenance and recovery technique before flying and never enter a spin below 5000’ AGL. I’m amazed at the number of pilots and instructors who recite a spin revovery technique omitting any mention of throttle or aileron. When I mention throttle / aileron some respond with blank looks, other say of course I would make the appropriate adjustments. I was recently doing some Upset recovery training with a professional pilot who didn’t understand the concept of “unloading”. He was adamant you must pull back on the control column to un-stall when inverted as it lowered the nose relative to the horizon! He couldn’t get the concept that angle of attack is in no way related to pitch attitude relative to the horizon! 2
Blueadventures Posted October 8, 2018 Posted October 8, 2018 Take a look at the strakes on the fuselage ahead of the tailplane on the DHC1 Chipmunk. These are also fitted to some Tiger Moths. I think the idea is that at high angles of attack like in a spin, there is a vortex generated by each of them which energises the airflow over the fin and rudder.I knew a bloke (cropduster pilot, now deceased after his last accident) once who spun a Tiger Moth into the ground and lived to tell the tale. The gliding club was hiring it as a towplane. He rented it to do a session of aerobatics and during this noted that it seemed a little reluctant to recover from a spin one way. The other way was fine. Told LAME, who checked the rigging. Next weekend flew it again. One way spin recovery was fine. The other way seemed a little reluctant still. Tried again and it kept spinning all the way into the ground. He turned off the fuel and ignition and tightened his harness and although injured, lived to fly again. Also knew a couple of blokes who were messing about in a Puchacz sailplane and got into a spin at 3500 feet and it would not recover. They were both highest level GFA instructors. Eventually for no known reason it came out and the recovery went down to 350 feet AGL. Lesson is, yes you possibly need spin recovery training fairly early in flight training. Do it in a Pitts or Decathlon, wear parachutes, go to 10,000 over the water or an unpopulated area and if it is still spinning at 5000 feet and you've tried all you can to recover, bail out. Remember the lesson anyway, mentally rehearse it often and NEVER spin accidently because as facthunter says, if you do it accidently it will likely be at low altitude where knowing how to recover will not help. If you are a GFA member you are now required to do spins on every annual check. I consider this a gross intrusion on your personal right to voluntarily select your level of risk exposure. BTW there does not seem to be any evidence that spin training or lack thereof has any effect on the accidental spin in rate. Canada had a PPL spin training requirement for years after the USA abandoned it in 1947 I think. Early in the 21st century Canada did the same after a review of the accident stats showed no difference EXCEPT that the Canadians were losing pilots and instructors in spin training. This was written up in Avweb at the time. My personal reminder in addition to Pilot notes for the aircraft about spins is to identify the direction of spin early so you know what direction will be the opposite rudder required. My reason is with gliding a good mate took a glass twin (Twin Astir) up after its annual release. Put it into a spin and applied what he thought was opposite rudder. Nothing happened so after a short time decided to try opposite rudder. Out she came. Meanwhile on the ground observing was the maintenance person and the CFI. CFI looks at John and asked what he did during the Form 2 service. Did at least 12 spins. (Provided enough time for the question to take place.) On landing the pilot said all his fault he used rudder to enter the spin; then applied opposite rudder to what he used to effect the spin. Was wrong; he did not observe the spin direction was that way. Top Pilot and instructor and person enough to admit error. He said he believed he was on his way to meet his maker. Plenty of time and he only applied opposite rudder to his spin recovery as what he elected to do was not working, needed to try something else. Good airmanship ensuring plenty of height before the spin check helped this time. In case the story doesn't read right. Intended spin entry, shortcut the recovery by applying opposite rudder to what was used to commence the spin; which is not what he always did or instructed, Did not recognise that he had the rudder full over in the direction of turn. Fortunately he decided as a last resort to use full rudder the other way; and stopped the spinning. I always seek to identify the direction at the start and as the spin develops. Cheers.
facthunter Posted October 8, 2018 Posted October 8, 2018 IF you put the plane into a spin deliberately you should know what direction it's spinning. If an inadvertent spin you may not be sure. This is why a gyro operated turn rate needle is probably the most important instrument in the basic panel.. OK what direction is it turning? Needle direction tells you .Also is it a spin or a spiral? That's important as the response actions are markedly different. So check AIR SPEED steady at not much above stall. You are spinning IF you have height you should be alright, but you are autorotating and your controls don't do much of what they generally do. Recovery as specified in POH SPEED increasing and "G" increasing .You are spiraling and rapidly loading the airframe. ALL controls work normally and you are descending fast but don't pull back on the stick. Roll wings level with aileron, close throttle and recover from dive carefully. You might be over Vne or put it into a spin if you pull too much "G". or overload the airframe dynamically. Spirals are not permitted to be taught in RAAus planes. Some are a bit fragile. and have low Vne.. "Spiraling in" used to cause more deaths than spinning. The "Graveyard spiral" is referred to frequently in early last Century flying. You are more likely to get into one in IMC or at night.. In fact if you aren't trained and current it's pretty much guaranteed, if not straight away, after you get a bit fatigued from concentrating in other than VMC.. Nev 2
Bruce Tuncks Posted October 8, 2018 Posted October 8, 2018 good stuff Nev. I don't think it applies to Jabirus though. I've never heard of a Jabiru stuck in a spin. My Jabiru has only a very small allowable flight C of G range. If they had a ballistic chute option, they would have ballast required for those who didn't install one. There is an awful video showing a ballistic chute deploying accidentally in the take-off and killing the pilot. Not in a Jabiru.
Guest extralite Posted October 8, 2018 Posted October 8, 2018 Il bite. The number of accidents I have read about whereby a ballistic parachute may have saved somone from a terrifying last few moments, and one I recently attended and felt what it must have been like to be the pilot. I'm reluctant to ever fly again without one. Yet t I keep hearing from people who oppose them on the basis of accidental deployment. I suspect it's more an excuse for it being too much extra bother. How many accidental deployments have their been? I suspect very few and I can't see how it could happen if properly installed. Obviously for an aircraft that I am confident in outlanding it's not needed.But for higher performing single engine aircraft, or when teaching spins or aeros in slippery rec aircraft, there seems little evidence that the risk outweighs the benefits.
alf jessup Posted October 8, 2018 Posted October 8, 2018 good stuff Nev. I don't think it applies to Jabirus though. I've never heard of a Jabiru stuck in a spin.My Jabiru has only a very small allowable flight C of G range. If they had a ballistic chute option, they would have ballast required for those who didn't install one. There is an awful video showing a ballistic chute deploying accidentally in the take-off and killing the pilot. Not in a Jabiru. Bruce Was that the one of the trike where the Buffooon just fitted it and had his activation handle/ cable connected too the control bar and when he pushed forward it activated That’s called you cannot teach stupidness Some are born with it A modern day ballistic chute requires about 15 to 20kg pressure to activate it 1
fly_tornado Posted October 8, 2018 Posted October 8, 2018 parachutes will just encourage people to use them! 1
Bruce Tuncks Posted October 8, 2018 Posted October 8, 2018 I reckon it was alf. There can't be too many videoed like that. I never heard why it went off too early, thanks for the info.
Bruce Tuncks Posted October 8, 2018 Posted October 8, 2018 Extralite, there are many aircraft which do not have the legal weight-carrying capacity to fit such a chute.
alf jessup Posted October 8, 2018 Posted October 8, 2018 parachutes will just encourage people to use them! Well FT It is actually there to be used if the need arises. Umm that’s what you fit them for isn’t it??? Or do people in Queensland just fit them for the sake of it, It’s ok we southerners can handle the extra hour of sunlight we get now, I can understand now why you lot don’t want it
djpacro Posted October 8, 2018 Posted October 8, 2018 I have a friend with one of these and he is interested about these matters. Cheers I didn't go to this event a year ago and I have no idea what came out of the discussion:
facthunter Posted October 8, 2018 Posted October 8, 2018 ft, That's exactly what the Brits said about their WW1 pilots and they burned to death frequently, as a consequence. A ballistic chute however is not wanted when you are on fire, where you need to get down and out of it as quickly as possible. Nev 1
horsefeathers Posted October 8, 2018 Posted October 8, 2018 Well FT...... It’s ok we southerners can handle the extra hour of sunlight we get now, I can understand now why you lot don’t want it We dont use parachutes in Queensland, cause the extra hour of sunlight fades them 1 2 1
Bruce Tuncks Posted October 8, 2018 Posted October 8, 2018 FT, did you know you were quoting those WW1 generals or whoever it was that denied their airmen parachutes? I actually thought you did and so the posting was tongue in cheek. For myself, I have worn a chute for about 50 years in gliders and never used one. And while the wings stay on, ( and its not on fire too much ) I reckon the plane is the better protection anyway, as long as you keep flying it right till you flare out on top of the scrub or wherever.
Jaba-who Posted October 9, 2018 Posted October 9, 2018 Il bite. The number of accidents I have read about whereby a ballistic parachute may have saved somone from a terrifying last few moments, and one I recently attended and felt what it must have been like to be the pilot. I'm reluctant to ever fly again without one. Yet t I keep hearing from people who oppose them on the basis of accidental deployment. I suspect it's more an excuse for it being too much extra bother. How many accidental deployments have their been? I suspect very few and I can't see how it could happen if properly installed. Obviously for an aircraft that I am confident in outlanding it's not needed.But for higher performing single engine aircraft, or when teaching spins or aeros in slippery rec aircraft, there seems little evidence that the risk outweighs the benefits. Humans have a number of inbuilt cognitive biases. One of them ( I forget it’s proper “xx bias” nomenclature ) is that when shown something new humans jump to an immediate opinion based on nothing more than a like or dislike. The strength that that this belief is held varies from person to person and is highest in the poorly educated or poorly experienced and sadly is more affected the older you get. In some studies age overrides experience or education. Only after this position is in place they then seek reasons to back up their already placed preference. Some people will go to extremes of irrational evidence to support this position while ignoring strong valid evidence that does not support their belief. 2
pmccarthy Posted October 9, 2018 Posted October 9, 2018 I know this is further thread drift, but... A good example of Jaba's point is this video. How anyone can watch this and then claim that we are causing sea level to rise is quite beyond me. How sea levels reshaped Western Australia's coastline over 125,000 years Archaeologists combine detailed scientific mapping with green screen technology usually found in big-budget Hollywood films to recreate the history of Western Australia's shifting coastline going back 125,000 years. Read the full story
facthunter Posted October 9, 2018 Posted October 9, 2018 Jaba who, It was called "selective perception" when I did Psych at University. Another trait is to do what you were taught "yesterday" to apply to today's situation. That was called retroactive inhibition.. Scary stuff, the human brain, especially in flight . Training and discipline needed, if your feet are not on the ground. Nev .
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