Ross

Hi Chris I just looked up my "Owners manual" for the as yet unbuilt J160 and I quote the figures from the J160 owners manual below for rev 0 dated May 04 Page 5-3 of 3. 5.2 Takeoff & Landing Distances Takeoff safety speed is 1.3 Vs1 64 KIAS Landing Approach speed (Full Flap) 65 KIAS The unfactored, sea-level takeoff distance to 50' at NIL wind or slope, on a short dry grass surface, is 350 metres. The sea-level takeoff strip length exceeds the landing strip length." Takeoff and Landing distance is therefore 350 metres times 1.3 =455 metres. This distance is established using the normal technique described in paragraph 4.3.7 (describes normal & short fieldtakeoff in J160 with the same rev0 and date May 04) This distance must be increased by a distance increment of 115 metres for each one thousand feet (1000') of pressure altitude. 5.3 Maximum CROSSWIND FOR TAKEOFF & LANDING 14 knots By my calculation for your strip w/o allowing for slope or wind that makesboth the takeoff & the landing distance requirement to be 455 metres plus 2.6 times 115 metres = 754 metres with no wind and no slope allowance. Regards

Hi Crew A Google search for Tebonin brought up the following site which implied that whenused on a group of testcats it increased their cerebral blood flow. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6674418&dopt=Abstract Regards

Hi Crew One point that worries me on the Jabiru is that the strut connect point on the wings is shielded by "flocked on" and screwed on fibreglass shielding. This makes the point of connection to the wing unavailable for tiedown ropes. The onlytype of load the struts should experience should be axial tension or very low compression but in the axial plane in line with the the centre line of the holes in the ends of the struts. That is load in line with the long length only. This would avoid bending the long small diameterstruts (ie very unsuitable for side loading by tying ropes on them any distance from their ends). Some GA aircraft actually have an eye bolt screwed into the underside of the wing to facilitate the tiedown. Others with struts have enough room around the connection for a rope to be threaded through the connection avoiding the problem altogether. Any suggestions Regards

He Ben Will hepassthe twinon the starboard side or the port side. Regards

Hi Chris For your elevation of 800 m about 2,625 feet AMSL there would be an increase in the true stall speed although the air speed indicator would usually indicate the same indicated air speed at the stall no matter what the elevation. So you still fly (mostly) by the airspeed indicator, just remember that it is IAS usually,not True Air Speed (TAS). It is really reading the pitot air pressure at the stall speed. Since the aeroplanes weight hasonly changed minutelyfrom sea level it still needs almost the same air pressure to make it fly. This means that the aircraft is travelling over the ground at a significantly higher velocitywhen it touches down on high airstrips.Now becauseenergy of the aeroplane, because of it's velocity, is proportional to the square of velocity a small increase in touchdown velocity compared to what happens at sea level produces a corresponding large increase in the landing run. We have not yet considered wind speed,slope or surface or pilot reaction time yet. Grass might help the landing, but won't be much use for the take off. All the above can be much worse when you convert to standard temperatures and pressures. The aerodrome altitude can be thousands of feet higher on a hot low pressure day. Take off on high airstrips- Less engine power available causes longer run, Less propellor thrust available at any particular revs causes longer run, Higher TAS (same IAS) required than at sea level causes lnger run, Longer take off run required even on level strip. Surface will affect run required can cause longer run Slope will affect run length required (uphill or downhill over cliff), Wind speed will affect run length required, Wave and rotors can drastically affect performance in lee of hilly areas I think relative humidity will also affect engine power and maybe pressure altitudes as well. Please check all of the above with a qualified flying instructor. Please excuse my rambling. I just had another look at your experience and all the above is no doubt old hat to you. Just tell me to shut up. Regards Ross

Hi Geoff Was it the UL which is quoted with a L/D of 17/1 versus the J160 of 10/1. It ought to have a noticeably shorter take off than the others. I thought there was some mention of a carbon fibre option wing. Anyone else know anything about it. Regards

Hi Clem Points taken. The figures no doubt are probably quoted for standard atmospheric conditions at sea level, nil wind, level surface, hard sealed surface, (even derate for hard short grass) engine warmed up and run in (J160c book says temp needle must have moved off the stop) within C of Gravity Limits and presumably should be at MTOW. For the complete conditions read the Owners Manual which is not on the Jabiru web site. If any of these conditions are not met derate accordingly. I just like my all over square mile of grassy clay loam at Leeton or the long biitumen at Griffith. Griffith always seems to have a cross wind from the South and the main wind sock is amongst the trees near the passenger terminal. Leetonis supposedly about 20 feet lower in the South West corner than where the gliding club hanger is. Griffith has a noticeable dip in it for final after touching down on 24 but like Leeton has the advantage of being not much above sea level. Then you need that on hot days. Jabiru also has another condition for hot days. "Maximum air temperature for operations 40 deg C for takeoff at gross weight." Regards Ross

According to the Jabiru site the J170 is kit only Vso 38 knots 140 metres Take off distance 150 metres Landing distance "Max useable load" 255 kg Regards

Hi Peter I have sent you a private message. Regards

Hi Peter That's great. I know exactly how you would have felt re flying and wifes reactions etc.My wife once said to me after her first and only flight in a Glider with me "It was OK until you started circling". Lesson one: Never take your wife flying until you have lots of flying experience and not in an Es52 Mark IV Kookaburra. Just do a circuit. She is yet to agree to fly in the Jabiru. If (I should say "when")I get my (our) J160 airborne, Echuca is one of the places I will have to visit as I have flown over it on a cross country training nav to Ballarat from Griffith. The trouble with Victoria is that there are far too many roads, towns, aerodromes, hills, lakes, rivers, restricted airspace etc compared to the Riverina! Once I crossed the river into Victoria, I just get one fix figured out and we are over the next one or two or three! We tracked YGTH, YTOC,YBDG,YBLT on the way down. By contrast, on the return trip (YBLT,YBDG,YDLQ, YGTH)as we passed over Deniliquin I think with about an hour to go in the Jabiru I could just see the range of hills North ofGriffith.There were no other major distracting landmarks of any consequence until we were within sight of Griffith. On track, there was the "Coleambally outfall canal" with poweline beside it at one point and I think this was about abeam of Coleambally. It has a distinctive bend in the canal if you intersect it at the right place. Regards Ross

Hi Chris I am slowly contending with my Jabiru J160 kit #14 (DEc 2004). Being early in the series before certification, there were/aremodifications to contend with. This would be far less of a problem now as the design settles down. I am not aware of any changes made since certification. Anumber of mods have been made in the area of the fuel header tank, carburettor jets to reduce fuel consumption in 2200 & 3300 motors (see Jabiru site for detail),undercarriage bolts, propellor attachment bolts and washers, oil cooler, oil pump, cabin reinforcement, door catches, windowsand hydraulic tappets. As far as I was concerned, the main one washydraulic tappets ("we are not considering them")and the factory mods to the oil pump and radiator although I have the later model oil radiator. Depending on the engine serial number the TBO has been changed in May 2004. Basically top overhaul at 1,000 hours and complete engine overhaul at 2,000 hours. See the detail on the Jabiru site in "Engine notices". If I had ordered the engine later I might have scored the hydraulic tappets. Some mods are mandatory on the 3300 motor but not on the 2200 motor. Not all of thesechanges were made mandatory. Most of them were recommended. If implimented some of the changes would reduce the frequency of required inspections or serviceing like the propellor bolt changes. There were also other changes made to layout of controls that did not figure in notices or recommendations for changes. I discovered a new problem last night in that my carport heaters could not beat the Leeton frost. Our minimum temp last night was about -5 deg C outside. This morning (her Golf Day)my wife was complaining that she could not get any water to have a shower before golf as our pressure pump was frozen up. That was was the first time for a number of years! We need about a minimum of 16 deg C for epoxy to cure according to Jabiru, preferably +25 deg C. Jabiru said that it will start to cure as soon as the temp rises even if some time later. The problem of course is keeping the workaligned, clamped or screwed together or not moved until it has cured. last night this took at least 16 hours until it was safe to unclamp where as normally I could get away with as little as sixto eight hours depending on the temperature. Epoxy curingis actually a chemical reaction. That is why it is important for the proportions of the epoxy and hardner to be correct by weight. Last night I gave up and I turned the 2.5 Kw fan heater off at midnight with the temp at6.9 deg C. By about 10 AM the next day it had cured enough to remove the self tappers after turning on the heater again at about 8 AM. The next day (tonight at 20:37) the temp was 14.9 deg C in the garage with the heater going all day with a maximum of 16.1 deg C sometime during the day! So it would have had a bitmore curing during that time but was still soft enough to make it relatively easy to do some rough trimming with a carbide scraper. If you leave it too long into the curing cycle, the self tapperscan be very very difficult to remove! Our kit arrived from the factory with oneself tapper still in the hull join and tooka bit of effort to remove. I might have to build a tent over the part I am working on in the winter if it involves curing epoxy or epoxy flockand put a fan heater in there. The curing time is considerably reduced if you can get it up to 25 deg C for a few hours. I am gratefull to Geoff from Mildura and his partner Geoff (not a typo) for help via email& photos during my kit building which has still a long way to go. Those two Geoffs have an advantage of working together and with years of experience in the gliding area. I wish he were a bit more forthcoming with his aerodrome identifiaction though. It would help if the photos could be numbered or named like they were in the previous forum. Regards Ross

Hi Crew Is yellow rope suitable for the cases below? What happens to the lift force when the wind speed changes to way above the clean stall speed? What about the difference between the lift on a tail dragger versus a tricycle UC with three wheels tied down on the ground? Is the taildragger already stalled when tied down for head winds & tail winds? What happens in both cases when the tail is into the wind? If we have negative flaps should they be applied for the tail dragger or for the tricycle when tied down? Regards

Hi Crew I would have thought the more important speed was manoeuvring speed. Now I am not considering flutter at all but from what I have heard is that flutter can happen and massive damage can occur almost before a pilot was aware it had happened but I think that occurs at or aboveVne and we can be in enough trouble long before we get near Vne from excessive g loads. So the following remarks are just based on the potential g loads that can occur on an aircraft. The following calculations are based on assuming the aircraft wings are subject to turbulent air flow rather than laminar. High performance gliders have more of their flight envelope in the laminar region which changes the L/D equation drastically from what occurs in turbulent flow conditions. Theroretically from what I remember learning in gliding the lift a normalwing can exert is proportional to the square of the true air speed of the unstalled wing. So if a wing on the point of stall flying straight and level isat 40 knots TAS it is exerting 1 g on the aeroplane. That wing at 80 knots TAScould without stalling exert the square of the ratio of the speeds times 1 g on the aeroplanei.e. (80/40x80/40)= 4 gs. So it could do a steep turn up to the point where it experiences 4 g at which point it would stall. At 120 knots TAS we are talking 9 gs or potentially 9times theweight of the aeroplane without the protection of the wing being able to stall before that happens whether it be a glider or a RAA aircraft. From what I understand anyone that flies an aeroplane at anything like near Vne would want to be doing it when the air was dead calm and use extremly small and gentle control inputs. For a mythical plane for which I havethe owners manual various speeds inmy owners manual are:- Clean stall power off is 52 KIAS read 1 g by my calculations Vno Max structural cruising speed 104 KIAS read 4 g possible by my calculation ("do not exceed this speed except in smooth air and then only with caution") Va Manoeuvring speed 104 KIAS read 4 g by my calculation ("Do not make full or abrupt control movements above this speed") Vne Never exceed speed 131 KIAS read 6.34 g possible by my calculation ("Do not exceed this speed in any operation") I think 6 g is close to or exceedsthe maximum acceleration that a fit human body could stand without blacking out. The flight load factor quoted for this plane is +3.8 and -2.0 Using my calculations 3.8 g could be experienced at the square root of 3.8 times clean stall speed of 52=101.4 Knots and that is before any gusts etc are taken into account. -2.0 g couldbe experienced at 73.5 Knots. Note that these are the g forces that the plane can be subjected too at the posted speeds in still calm air. If there are strong thermals or gusts or wind shear etc the air speeds can increase dramatically at any initial IAS with a subsequent dramatic increase in possible g loads on the airframe. One dayin a glider winch launch over the airfield at Leeton I experienced continuous wind shear and saw the air speed jump from about 60 knots to about 80 knots. This was at about 500 feet AGL Because the glider is in a very steep angle of attack when winch launching and carrying a lot of extra weight (up to part of the weight of possibly a mile of cable which the pilot cannot feel) it is normally flown with a weak link in the cable at what must be close to the stall (with the extra weight) to help reduce the possibility ofsudden gust loads. So the pilot's defense is to get the nose over to reduce the angle of attack, signal the winch driver to slow down,to reduce the load on the wings on this particular aircraft and release the cable if the winch driver has not reduced power. Hopefully the winch driver will sense the extra load and reduce the speed and power applied to the winch wire before the speed increases too much. It is always best to have an experienced pilot as a winch driver. Sometimes, with a wide awake winch man, the winch might actually be stopped and the glider be "kited" up by the pilot and the cable released by the pilot when he is high enough. The speed changealso did the opposite with a large drop in air speed as I came in to land and it kept thisup for a couple of hours. A bit later onanother pilot had a cable break, surprise surprise. A glider pilot would immediately put the nose over with any slow down in speed even without a cable break. Immediately gentle nose over - about 5 seconds available to do this before a stall at the same time release what is left of the cable if any- it usually would self release -get to a safe air speed before doing anything else - there is no height to play with if sufficient space ahead - full dive brakes -land straight ahead, still about 400 metres left after stopping. It is nice to have a big paddock! Apologies on the length of these comments. It is bed time anyway! Contradictory views,better explanation or commentson these points arewelcome. Probably rules applicable to gliding have changed since I stopped doing it but the engineering does not often change. Regards Ross

Hi Crew It would be helpful for these type of questions to be answered by constructive information then we might all learn something. The colour scheme is a start - have we got any more suggestions? Regards

Hi Crew Remembering that wake turbulence does not start until an aircraft is airborne or perhaps has the nose wheel off the groundand in the case of landing stops once the wheels are on the ground. Regards Ross

Hi Techman Could we be a little more specific when taking about Jabirus. Everyone seems to imply that the modelsare all the same. There is a lot of difference even within the same model. I have J160 kit and that front shock looks suspiciously like the one in my kit so I would very much like to know a bit more detail. [ATTACH]849[/ATTACH] Likeabout what model it was, kit or factory built, what was the serial serial number of the fuselage, engine number,when was the part manufactured,was it original equipment etc etc. Regards

A nice clean skin then! Regards

In 1985 in California near Sacramento as a passenger in a Cessna I once saw the view of an aeroplane like the one in your third picture. We were not on the ground. So I reckon if you want to make it look more realistic it should have dark streaks of oil leading from below the engine along about one third to half the length of the fuselage. The picture has kind of stuck in my memory. Regards

Hi Peter We have potentially the same situation in Griffith which can be a busy AG plane and helicopter base plus RPT,ambulance and various other courier services besides the charter and training work by the aero club which handles GA and RAA aircraft. My last experience of it when flying the Jabiru was the "croppy" pilot calling me up when I had just turned final for 06asking if he could take off - he was waiting off the strip near point C on the ERSA drawing with engine running - I said no - he acknowled this message andwaited till I landed and had cleared the strip via the taxiway marked A opposite the passenger terminal. So this guy knows how to use a radio and does. By the time I could look back to see where he was up to he had gone. My circuits were probably pretty wide and tenative at that time. On reflection later, I think he could have easily taken off and cleared the runway before I would have rounded out. They have big engines and usually have pretty impressive takeoff ability even when fully loaded. They alsooften fly out of Griffith empty (no load) and load up with chemical or fertiliser or seed on a strip near where they are working. The other aspect of flying at Griffith is that most people on the airfield on a Friday afternoon have a few thirst quenches at the Griffith Aero Club. This allows all local flyers whether they be students GA, or student RAA, plus the Ag operators pilots and crew, the local airfield workshop mechanics, Ag helicopter crews and the Aero Club instructors to talk to one another which is a great help in improving relations and sorting out problems or just general bull yarns. Even local GA pilots not flying on the day often come out from town or their farms on a Friday evening! Regards

Hi Glider forum I was just a club flyer at Leeton but managed to get as far as getting my Gold distance and Diamond Goal (I think that's right or vice versa). It took the form of a 300 km flight in a Club Libelle from Leeton, Junee, YWWL, Leeton with those declared turning points and all according to FAI rules with a sealed recording barograph on board to prove that you did not land anywhere else. The turnpoints had to be photographed with the wing rego in the photo as well as well taken in the correct sector. Ideally that was outside the turnpoint on the extended bisector of the turnpoint angle. I'll leave the Gold Height attempt to another time. This 300 km started witha winch launch from Brobenah gliding strip. I would think that few peoplewould havedone that flight in as long as it took me. It was about six hours averaging less than 50 Km/hour including thermalling and digressing into Leeton and back to Brobenah airstrip when I returned. One of the most satisfying things about these flights is the relief of getting off your backside and even more so in competition flying where you are sitting on a parachute that has no hint of padding in it. We had a policy of that after either three hours or five hours, I can't remember which, you flew at no charge. I had a bit to catch up on as earlier when I was attemptingone of the requirements of the Silver C, a five hour duration flight for the second time, I managed to land five minutes short of the five hours. I probably would have had an urgument with a couple of fences if I had tried to last another five minutes. But that was also completed a few week later. Another part of the Silver C was to fly 50 km from base and land out - I guess it would be classed as a fail if you managed to damage the aircraft although I do not ever remember it being an issue here at Leeton. Regards

Hi Paul That sounds like an idea that couldwork if people are game enough to stick their necks out firstly in giving an example whether it be real or imagined and next doing it again by offering a solution or a number of alternative solutions. Or we could set upmultiple choice quizes like those used to test GA pilots.I did my RAA training at Griffith Aero Club. The hired JabiruI flew I think had about 50 hours on it when I started.Up 'tillthen the Griffith Aero Club had been almost exclusively involved in GA pilot training. I found a number of quizes used for GA training.I found them to be quite usefulin my case in expanding and clarifying airmanship and and technical issues when qualifying fortheendorsements onmy "Official Certificate" from Recreational Aviation Australia ABN 40 070 931 645. Of course the quizes werefor GA pilots but we still need to understand what GA pilots are doing and they need to understand what we are doing. There was little in most of the quizes that was not applicable to RAA pilots. I think that setting up the quizes could covera lotof the situations that occur but Paul's idea would be used for more clarification when required by anybody. It obviously could dealwith new situations not covered by the present rules and regulations. As Paul says it would present an opportunity to put a number of viewpoints on these isuues, a debate if you like. Of course both venues would not onlycover rules and regulations. Anothergainwould be in explaining technical flying issuesand new equipment. Quite a few people seem to want to be anonymous in these forums which I feel reduces the effectiveness of their comments. I feel as though I always want to know where does this person come from and what is their name. Regards

Ian, Thanks for that. Yes, it does seem rather incongruous that there is no formal requirement to get an endorsement. It may may have been inconvenient in the past but now that there are a lot more bodies out there it would seem logical to make it mandatory. Bo Doubt it would help the reputation of the organisation as well. Regards

Hi Crew I think Paul has agood point here. I do not see why we would have to have a different category for each RAA aircraft out there. We seem to have a confusing number already. It seems not very sensible to assume that flying lessons and experience in one model of RAA aircraft will be equally applicable to all other models and brands despite the fact that relatively low performace aircraft are getting far more docile than their older cousins. Sometimes there are distinctive differences in flying behaviour or response to control inputs between two planes of the same model and manufacturer. I thought the RAA had given up letting students teach themselves to fly. The suggestion of getting an endorsement for each variant seems very sensible to me. I would have thought that was already a requirement. Could Ian or somebody else enlighten me on this point. I don't think anyone would try flying in an unfamiliar model of a GA aircraft or glider without being endorsed on that aircraft even if on some types thatmight only require an hours flying. I still remember, as a low time pilot, the thrill and butterflies experienced when transiting from a low performance two seater glider to a "very slippery for us" (for that era)single seater fibreglass glider, the Club Libelle L/D 1 in 35 I think. We kept being told that we should learn in the old low performance gliders and eventually move to the higher performance machines as that would be the safest way to do it. I was never really convinced on that point having seen the ES52 Mark IV Kookaburra not make it around the circuit one day and having to landat what should have been early final or late base. We did not have a slippery two seater anyway. So we had to do the Kookaburra and Blanik first. There were other aircraft in later years. The change in flying characteristics, position of things like fuel valves, flap handles or buttons, even the operation of differnt radios, flap lowering speeds, stall speeds, height loss in a full stall or incipient spin,spin recovery, fuel management, periodic maintenance especially for owners etc etc can all have a drastic effect on a pilot under pressure if he or she is not familiar with that particular aeroplane. Regards Ross

Hi Crew My first experience of Instructors was at Narromine about thirty years ago. There were two GA instructors available and one aeroplane, a PA28-140with a 150HP Lycoming and I got to go with whoever they decided. I also think that I was the only student at the time. I never saw or talked to another student. Unknown to me at the time there used be two planes the same butthe other plane had crashed into powelines not long before and burnt killing the two occupants. They were buzzing a farm house north of Narromine. The instructor I got was trying to get his hours up to move on to better things. I did my TIF with the junior instructorand eventually after threehours of further lessons he gave up saying I was hopeless despite my doingexactly as he told me or so I thought at the time. One of my problems is that being an engineering type I usually thoughtthat people like instructors meant what they said. I have since learnt that very few people can explain exactly what they mean when giving a set of instructions. Try explaining what you do in the last 50 feet of landing an aeroplane and getting it onto all three wheels and stopped. The senior instructor took over and fourhours later sent me solo. The main difference was that the junior instructorgave instructions of what to do and where to do it with no explanation of why whereas the senior instructor gave more explanation of why and how you did it. This is not an easy task in the example of when you are approaching the threshold on late final with a student pilot. The student pilot initially thinksall this is easy or hard depending on the conditions of the day for that first flight and he wonders why it is not the same next time he trys it unless he has an instructor that tells him that every landing or flying experience will be unique or different. As others have pointed out all this usually comes with experience but I think that that experience will be better interpreted by the pilot if he has some explanation given him so that he can make decisions as conditions change. So the studenthas to learn to cope with the varying conditions and keep within the allowable parameters of his aeroplane and the rules of flying. So the instructor has to be able to give the student the ability to make the rapid decisions required. Shortly after going solo, with 1 1/2 hours solologged,we moved to Leeton and as flying training in Griffith at the time was substantilly dearer than Narromine I took up gliding at our Brobenah airstrip with the Leeton Gliding Club. So I had to start again and cope withevery flight ending in a forced landing. I was still wearing the problems of that first junior instructor and it took quite a while to undo flying by the numbers and fly according to the conditions. So now I have given up club glider flying after about 192 hours glider time andfive hundred and fifty one (551) landings, it was a winch club, and taken up RAA flying in a Jabru with tricycle undercarriage again. That was a challege after years of taildragging gliders. I still think that some instructors should give more explanations than they commonly do but of course the student pilot can be easily overloaded and the instructor has to know when to shut up. I am amazed at the tolerance and patience of instructors that I fly with. I would probably be terrified if I were doing it. Regards

Often in western areas where there are grazing stock in paddocks with few trees if any at all, the small area probably a metre or so wide around the base of power poles may be bare of grass. Stock often use poles, fenceposts or trees as back or rather body scratchers. This often provides a stark contrast in colour to the surrounding general grass land or crop colour. In a drought situation everything may be the same colour including the air and the poles. Regards Old not bold glider pilot