dazza 38 Posted January 28, 2015 Posted January 28, 2015 I had a 1983 hilux 4WD, 2 ltr petrol back in the day, it was a 4 speed manual. It was valve bouncing at 125 kph, going down hill. It was flat out doing 110 kph. It still didnt miss a beat for over 100 000 kays.
dazza 38 Posted January 28, 2015 Posted January 28, 2015 If I ran my motorbike engine for more than a few seconds at 75% there would be someone behind me at 100% and party lights.BAP. Sure the same as my KTM1190, but I would be doing well over 200 kph. It depends on the size of the bike.
Kyle Communications Posted January 28, 2015 Posted January 28, 2015 I had a 1983 hilux 4WD, 2 ltr petrol back in the day, it was a 4 speed manual. It was valve bouncing at 125 kph, going down hill. It was flat out doing 110 kph. It still didnt miss a beat for over 100 000 kays. I have a 1980 Hilux Ute up at my farm as a dunger we use around the farm and use locally..its got 300,000 km on it...5th gear is a bit loud so I don't use it but it still goes...good old diesels Mark 1
Bruce Tuncks Posted January 28, 2015 Posted January 28, 2015 well Dazza, there is a wonderful business opportunity for you here.. just get up a fool proof , light and cheap air cooled aero engine. You will be the first in the world to do it, and I will buy one.
dazza 38 Posted January 28, 2015 Posted January 28, 2015 well Dazza, there is a wonderful business opportunity for you here.. just get up a fool proof , light and cheap air cooled aero engine. You will be the first in the world to do it, and I will buy one. It would have to be liquid cooled. Air cooled is so old school and causes half the maintenance issues. It wont be cheap either, cheap engines need to be worked on every five minutes. Nothing is cheap in aviation, but I reckon Honda or Yamaha with their budgets could make a reliable alternate engine to the 912.
pmccarthy Posted January 28, 2015 Posted January 28, 2015 My 1500cc VW beetle owner's manual said recommended maximum and cruising speed 68mph. Due to the restrictive valves it wouldn't go any faster. Nearly 50 years old now if it still exists. My 912 gives me the same warm feeling. I just need to manage the CHT and everything else works as it should, it will cruise along all day. 1
Geoff13 Posted January 28, 2015 Posted January 28, 2015 Then you don't understand the basis of engine certification / certifying. The performance figures for aircraft are based (mostly) on that exact premise: full power for take-off, cruise power for steady level flight. What car regularly - if EVER - runs at full throttle for 5 minutes as soon as the engine is up to operating temperature? Or runs at a constant 75% power for the full duration of a multi-hour journey? Get real. My SS Ute runs at full power straight after warm up but it is normally only for about 3 seconds until we get up to speed then this happens. 1
jetjr Posted January 28, 2015 Posted January 28, 2015 Isnt that what was said, auto engines dont run wot for 5 minutes
David Isaac Posted January 28, 2015 Posted January 28, 2015 Isnt that what was said, auto engines dont run wot for 5 minutes That is the real issue. Wide Open Throttle (WOT). The next best comparison is in boating application and in particular boat racing. I know I used to build them and blow them up. WOT as a crude comparison is like driving an automatic vehicle (with high stall torque converter) up against an immovable object and opening the throttle to full power and holding it there for a significant period. Apart from the obvious overheat of the transmission the point is that is the effect of an aeroplane propellor and the effect of boat racing at WOT. Auto engines are NOT driven around at WOT for extended periods and even at highway cruise speeds they are not anywhere near 75% power continuous operation. Towing a heavy caravan up a long continuos hill is the nearest comparison, and we know the overheat issues here unless the vehicle is properly designed for this purpose like my V8 TD in my Landcruiser and at times in hot weather I have to back off and go down a gear to avoid an overheat. 1
pmccarthy Posted January 28, 2015 Posted January 28, 2015 My point about the VW was that it could be and was driven at WOT all day in very hot weather and it was air cooled. The recommended maximum and cruising speeds were the same, and if you pushed the pedal harder there was nothing more to give.
dazza 38 Posted January 28, 2015 Posted January 28, 2015 That is the real issue. Wide Open Throttle (WOT).The next best comparison is in boating application and in particular boat racing. I know I used to build them and blow them up. WOT as a crude comparison is like driving an automatic vehicle (with high stall torque converter) up against an immovable object and opening the throttle to full power and holding it there for a significant period. Apart from the obvious overheat of the transmission the point is that is the effect of an aeroplane propellor and the effect of boat racing at WOT. Auto engines are NOT driven around at WOT for extended periods and even at highway cruise speeds they are not anywhere near 75% power continuous operation. Towing a heavy caravan up a long continuos hill is the nearest comparison, and we know the overheat issues here unless the vehicle is properly designed for this purpose like my V8 TD in my Landcruiser and at times in hot weather I have to back off and go down a gear to avoid an overheat. Yeah well you obviously have never owned or driven a 1983 Toyota Hilux fitted with a 4 speed manual that was revving its ring out on the highway at 110 kays an hour and have a engine that simply couldn't be revved any higher , it was at MAX RPM at 120 and I drove it at 120 for many contnuous hours. Believe what you want and I will believe what I think.
David Isaac Posted January 28, 2015 Posted January 28, 2015 Yeah well you obviously have never owned or driven a 1983 Toyota Hilux fitted with a 4 speed manual that was revving its ring out on the highway at 110 kays an hour and have a engine that simply couldn't be revved any higher , it was at MAX RPM at 120 and I drove it at 120 for many contnuous hours.Believe what you want and I will believe what I think. It may well have been at max revs Dazz, but was it continuously at WOT, and in any case probably not much power (kilowatt) output. The VW engine was a unique example of cruise and max speed being the same; 72 mph from memory, with a warning that the car will be aerodynamically unstable at speeds in excess of 70 mph. Neither of those engines are typical, and the VW the only one light enough to use in aircraft but underpowered for most applications. We are looking for power at WOT in an aircraft application. NOT having a go at you buddy.
pmccarthy Posted January 28, 2015 Posted January 28, 2015 David your memory is better than mine, it was 72mph. I was going faster than I remembered, lots of trips from Broken Hill to Griffith in summer. 1
Russ Posted January 28, 2015 Posted January 28, 2015 Auto engines can't handle WOT continuous.......well subarus sure can. I've got 30plus yrs flying gyros, soobs are dominant, generally from a wrecking yard, bolt into a gyro. These engines run yr after yr after yr at HIGH rev settings.....example or 2 .....1800cc / EA 81 engines, full power 5000 thereabouts, cruise all day 4600. 2500cc / ej25, full power 5600, cruise all day 4600. Soob engines get massive hrs before you put a spanner on them, it's rare to have an engine out, they just keep screaming. Downside......heavy little suckers.
David Isaac Posted January 28, 2015 Posted January 28, 2015 Everything is a compromise and there are exceptions. Weight for power is always the killer. You can use an aluminium Chevy V8 with a reduction drive and they are available, BUT will you get good TBO? Again, weight weight weight. If they were widely successful we would surely see a wider acceptance and use. The Honda Viking is another example ... time will tell.
David Isaac Posted January 28, 2015 Posted January 28, 2015 Russ if I understand you correctly full power is 5000 RPM at WOT, is that correct? So then 4600 all day is NOT at WOT? Mind you some aero engines have limits in time on WOT at sea level.
Russ Posted January 28, 2015 Posted January 28, 2015 That's correct, I was showing power settings max and cruise, cruise revs for a auto engine are high in the scale when held there for continuous . 400 revs off max is not much off peak ( auto engines ) Rotax etc actually designed to run continuous high revs, auto folks weren't envisaging their engines running aircraft, with completely different operating parameters as they were originally designed to operate. Other auto engines proving substance as aero engines are the little Suzuki turbo'd ones 1200 and 1600cc, the 1600 especially . My point is, there are some auto engines that actually perform really good as aero engines.......not many tho. 3
turboplanner Posted January 28, 2015 Posted January 28, 2015 I think the term you are looking for is "constant loading", which an aircraft, outboard motor, and 0n-highway truck, and air cooled stationary engine have in common, where the engine is under maximum or near maximum load continuously. In these conditions the temperature starts to make the first half of a bell curve, then flatlines at the design temperature. Car engines, road bikes, and Urban truck engines have "intermittent loading cycles", where the engine heats up when it is pulling hard, but cools again with the gear changes ( a part exception being when cars and bikes are cruised at high speed, particularly into-wind and meet the "constant loading" definition.) Constant loading applications in Australia require additional design work to the engine basics, and cooling system for acceptable life. WOT racing in applications where the engines are constantly loaded, such as the drag boating David is talking about, drag racing, and speedway are constant loading applications, whereas circuit racing is intermittant racing. Circuit racing engines usually fail quickly on speedways, so the development paths are quite different. WOT operation with light or intermittant operation generally shake the engine apart rather than show upper cylinder symptoms. Cooling issues with any of these issues are usually common to all production units and occur at a predictable point. (poor assembly and servicing excepted)
facthunter Posted January 29, 2015 Posted January 29, 2015 A low output engines like the 83 Toyota and the VW are more likely to go on full throttle for hours if they don't overheat somewhere. Oil, or parts of the head and steam pockets (Dust on the VW) . A high specific output engine like a modern turbo diesel will probably do it too provided the engine is cooled effectively and everything is done right. Consistently worked hard these engines do fail .more than the lower power ones.( everything else being equal) as things are more critical. You are running right ona lot of limits and they usually use only the makers oil. In aircraft, unless they are in a military application where reduced life is accepted, the engine is flown conservatively as a derated engine, where it may be only 2/3rd of the military output. In Jets they will run higher TGT's than civilian. With an aircooled aero engine, non fan assisted, you will find that at about 50 hp per litre capacity, you will start running into problems with cooling. It's not all bad because the engine is often lighter and horsepower for weight is probably more important. Nev
dazza 38 Posted January 29, 2015 Posted January 29, 2015 It may well have been at max revs Dazz, but was it continuously at WOT, and in any case probably not much power (kilowatt) output.The VW engine was a unique example of cruise and max speed being the same; 72 mph from memory, with a warning that the car will be aerodynamically unstable at speeds in excess of 70 mph. Neither of those engines are typical, and the VW the only one light enough to use in aircraft but underpowered for most applications. We are looking for power at WOT in an aircraft application. NOT having a go at you buddy. The 2 ltr Petrol engine made a MASSIVE 72 horsepower at 4200 RPM Hence you could drive it all day long with your flat to the floor.
SDQDI Posted January 29, 2015 Posted January 29, 2015 Speaking about the difference in throttle use and power setting differences in auto engines compared to aero engines is even less relevant than the rotax to jab comparisons and that was decided to be irrelevant!!!!!
turboplanner Posted January 29, 2015 Posted January 29, 2015 SD there have been people on these threads making outrageous and irrelevant claims to back the agendas they are running. Consequently much of the discussion is at cross purposes. Sure auto and air applications are different in many respects, but they are exactly the same in others. We are not going to get clear of the agendas in this thread and nor was the thread about engine design. 1
Oscar Posted January 29, 2015 Posted January 29, 2015 The 2 ltr Petrol engine made a MASSIVE 72 horsepower at 4200 RPM Hence you could drive it all day long with your flat to the floor. And the damn things weigh, with their integral cast bell housing, more than a Jab LSA55 empty. This whole diversion has been of zero relevance to the thread topic; my beloved VFR 750 engine and the BMW K100 engine I have sitting in my workshop will both run all day at 75% power and they both produce over 100 hp - and they both weigh more than a Jab 2200 even without a PSRU attached, according to my scales. If motorcycle engines were a viable alternative, they'd be seen in huge numbers in experimentals; a few BMW R75/90/100 engines have been used (and even a few Harley Boat Anchors), but the results have not caused any shake-up of the aero engine market. The ONLY non-aero engine developed ( aka 'car conversion') engines that have made any significant inroads into the ultralight aircraft engine market are VW conversions and Subaru EA81 conversions - and they are both heavy for the delivered hp, though some turbo conversions of the EA81 start to be respectable. Many others have been tried; the Suzuki /GM GEO variants have some success, the Viking will probably fail just as every other Eggenfeller venture has turned to dross, probably more to do with the extreme dodgyness of the entrepreneur than the engine itself. Jabiru engines are, worldwide, the second most numerous engines in service after the Rotax 912X series in the 'ultralight'/LSA class of aircraft. CASA has placed limitations on the operation of Jabiru-engined aircraft that are more onerous than for aircraft that have engines with higher recognised failure rates or engines that have such low representation in the statistics that they don't present themselves on the radar. CASA has drawn a line in the sand for reliability - but has not applied that standard unequivocally. The CASA instrument cannot be seen as anything other than a specific and targeted attack on Jabiru engines. If CASA had defined a 'failure rate' of XX per XX hours of operation as unacceptable, then that is a quantitive expression of a de-facto standard that CASA has determined for engine reliability. NO quantitative figures have been defined; the measure has been 'more than Rotax'. There is NO international standard for aero-engine reliability. Equally, there is no international standard for 'survivability / serious injury' rate for aircraft. If there were, we can all name quite a number of LSA, GA experimental / GA aircraft that would be subject to limitations before Jabiru aircraft. In fact, if the CASA 2014 statistics base period was applied just to fatals alone, we'd be seeing no passengers without signed release statements or student solo flights in Savannah, Tecnam, RV, Morgan, Cessna and a few others, for a start. That improved reliability for Jabiru engines is a desirable state, is not an issue - it is a given. That the CASA instrument is a bugger's muddle, is obvious to anybody other than those who bear a vendetta-level grudge against Jabiru. 1 10
facthunter Posted January 29, 2015 Posted January 29, 2015 The only fault in that, is your gratuitous reference to Harley Boat anchors which you are treating in a way you resent Jabiru being treated. Modern HD's are right at the limit of aircooled reliable performance and have been higher quality , right through than non owners or people who don't work on them understand. I owned an ex Frank Musset 1947 1200 "U" model outfit that had done 350,000 MILES carrying other Harleys in a sidebox weighing so much two people couldn't carry the sidebox alone. The bike is still in excellent condition particularly notable is the frame which has no sign of any cracks whatever. I don't own it now. Nev 1
dazza 38 Posted January 29, 2015 Posted January 29, 2015 And the damn things weigh, with their integral cast bell housing, more than a Jab LSA55 empty. This whole diversion has been of zero relevance to the thread topic; my beloved VFR 750 engine and the BMW K100 engine I have sitting in my workshop will both run all day at 75% power and they both produce over 100 hp - and they both weigh more than a Jab 2200 even without a PSRU attached, according to my scales. If motorcycle engines were a viable alternative, they'd be seen in huge numbers in experimentals; a few BMW R75/90/100 engines have been used (and even a few Harley Boat Anchors), but the results have not caused any shake-up of the aero engine market. The ONLY non-aero engine developed ( aka 'car conversion') engines that have made any significant inroads into the ultralight aircraft engine market are VW conversions and Subaru EA81 conversions - and they are both heavy for the delivered hp, though some turbo conversions of the EA81 start to be respectable. Many others have been tried; the Suzuki /GM GEO variants have some success, the Viking will probably fail just as every other Eggenfeller venture has turned to dross, probably more to do with the extreme dodgyness of the entrepreneur than the engine itself. Jabiru engines are, worldwide, the second most numerous engines in service after the Rotax 912X series in the 'ultralight'/LSA class of aircraft. CASA has placed limitations on the operation of Jabiru-engined aircraft that are more onerous than for aircraft that have engines with higher recognised failure rates or engines that have such low representation in the statistics that they don't present themselves on the radar. CASA has drawn a line in the sand for reliability - but has not applied that standard unequivocally. The CASA instrument cannot be seen as anything other than a specific and targeted attack on Jabiru engines. If CASA had defined a 'failure rate' of XX per XX hours of operation as unacceptable, then that is a quantitive expression of a de-facto standard that CASA has determined for engine reliability. NO quantitative figures have been defined; the measure has been 'more than Rotax'. There is NO international standard for aero-engine reliability. Equally, there is no international standard for 'survivability / serious injury' rate for aircraft. If there were, we can all name quite a number of LSA, GA experimental / GA aircraft that would be subject to limitations before Jabiru aircraft. In fact, if the CASA 2014 statistics base period was applied just to fatals alone, we'd be seeing no passengers without signed release statements or student solo flights in Savannah, Tecnam, RV, Morgan, Cessna and a few others, for a start. That improved reliability for Jabiru engines is a desirable state, is not an issue - it is a given. That the CASA instrument is a bugger's muddle, is obvious to anybody other than those who bear a vendetta-level grudge against Jabiru. Yeah well lets just see how successful the SMART mercedes automobile based engines go. www.flyeco.net . They are the way of the future, your engine is old school.
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