Guest Andys@coffs Posted December 4, 2014 Share Posted December 4, 2014 QUOTE="Andys@coffs, post: 464060, "Even the nascar average speed of 80miles per hour" Nascar average speed is 80mph?........... Well yes I suppose it might be IF you run at 200MPH (is that flat knakker?) for 496 laps Then there's a crash 4 laps from the end and they circulate at 40mph for 20 minutes... Great statistics, you should get a job with Jabiru Sorry poorly written on my behalf, I don't mean that was nascar general stats rather the stats used were sourced directly from the video itself. If you watch you'll see that they run a f150 on a nascar track in Florida and average 80mph for the segment for the 150 pulling a huge trailer loaded up with 2 real??? NASCAR cars. This was a ford marketing video so the "great statistics" come from ford not me.... Did you watch the video? Andy Link to comment Share on other sites More sharing options...
Guest Andys@coffs Posted December 4, 2014 Share Posted December 4, 2014 Bex What about the ford claim that 300 hours of full dyno running represent 150,000 miles. Doesn't that stat alone suggest that the claims that car engines make fine aviation engines might not directly stack up? Andy Link to comment Share on other sites More sharing options...
Old Koreelah Posted December 4, 2014 Share Posted December 4, 2014 ..."Take off" 1200cc Beemer would make that 2200 jab of yours look like a seriously sick slug....But 160lbs... ...every car and motorcycle engine I investigated, once fitted with redrive, radiator, etc, was heavier than a Jab 2.2. 3 Link to comment Share on other sites More sharing options...
geoffreywh Posted December 4, 2014 Share Posted December 4, 2014 in a previous life I built speedway 3/4 midgets engines in NZ. We use single ohc Honda's running 14-1 on methanol. Engine was mounted north south with shaft drive and diff. The point is we cut the gearbox off and welded a plate on the big hole and took the drive off the l/h end of the crank. Never failed!..... They were quite light....Because your situation is special you may have to do it yourself....Big Job though... Link to comment Share on other sites More sharing options...
facthunter Posted December 4, 2014 Share Posted December 4, 2014 The actual HP per Litre of engine capacity is not the prime way you judge an aero engine. It is specific fuel consumption, physical size, mass, Torque and horsepower sustainable for longish periods and reliability.. An air cooled engine without forced (fan assisted) cooling is unlikely to be able to produce much over 40 HP/Litre because you are unable to get the heat out of it, as it may have to run at full throttle for expended periods.. Outstanding race engines are built to other parameters where peak power and acceleration are the exciting aspects. The aero engine has to perform in a boringly reliable way and not excite you excessively by stopping. Porsche have a good reputation for making good engines, but their venture into aero engine manufacturing wasn't successful. The Bugatti ones in their day were notably unreliable, but I'm not a great fan of many of their designs. Nev Link to comment Share on other sites More sharing options...
geoffreywh Posted December 5, 2014 Share Posted December 5, 2014 Correct of course.......................... BUT A high bhp/litre figure is a good measure of an engines' efficiency. Torque figures are redundant as we are always talking about geared motors. Thus the ability to turn a large dia prop is always present. Fuel consumption will be the same...you need to burn fuel to make power. More fuel =more power. (within reasonable parameters.) or more interestingly, more power=more fuel. We are looking for light weight and reliability. This is the domain of modern motorcycle engines (with exceptions) Reliability is ,these days, always present. If the engine is configured to run at 50% or 75% of max output constantly makes not so much difference....Cooling will be the main reliability factor. Bex recommended the GSX/Fj1300 series.. The Bandit 1400 looks better to me being oil/air cooled and fuel injected. 106hp @ 6800 rpm.... Gotta lighten it though..........Cut the gearbox off, drive from the alternator end of the crank, belt drive the prop shaft.(Don't forget to to get rid of nasty side loads). Should run at 4500rpm all day.(oops, sounds like a Rotax!) ...I wish I were younger........ Link to comment Share on other sites More sharing options...
facthunter Posted December 5, 2014 Share Posted December 5, 2014 YOU might ALWAYS talk about geared motors but it isn't mandated. so TORQUE is relevant. as thrust is in a turbofan.. Also some high performance engines have an atrocious specific fuel consumption. High revs and minimum friction aren't compatible as it's "square" relationship. The argument you are putting up has been done over and over. Where are all the motorcycle engined wonders? They are good but they are built for a purpose. Motorcycles and mass production techniques for cheapness of unit cost. Nev Link to comment Share on other sites More sharing options...
geoffreywh Posted December 5, 2014 Share Posted December 5, 2014 If you want an efficient engine developing more than 30 or 40 bhp per litre .............you will have to run it at more than 2700rpm.... That's a fact...So A modern motor will have to be geared....Where are all the motorcycle engined wonders? they're all over the sky and they're called Rotaxes....100hp from 1.2ltr......I just don't have the time (anymore) to develop a crankcase to take m/c parts.....I wish I did.... Link to comment Share on other sites More sharing options...
facthunter Posted December 5, 2014 Share Posted December 5, 2014 Things aren't a fact just because you say so Geoff. If you want more horsepower, from a smaller capacity engine, run a geared engine or your prop is too big to rev high, do the same . I agree with those propositions. I don't think you have actually read my points.. Not everyone sees a small high revving geared motor, liquid cooled as the ONLY answer for their aviation needs... You appear to. Do you really think a Rotax 912 resembles a motorcycle motor? I would no more fit that engine to a modern motorcycle than I would fit a modern motorcycle engine to an aeroplane. The engines cannot be optimum for BOTH Nev 1 Link to comment Share on other sites More sharing options...
fly_tornado Posted December 5, 2014 Share Posted December 5, 2014 plenty of city car engines (1-1.5Ltr) that are better candidates for LSA class planes than modern bike engines. Hard to believe people flew with Ford model A engines since the 1930s Link to comment Share on other sites More sharing options...
facthunter Posted December 5, 2014 Share Posted December 5, 2014 I HOPE you still COULD. They chiselled a bit of weight off the block and they are direct drive. Yay Pietenpol!!. Nev 1 Link to comment Share on other sites More sharing options...
dlegg Posted December 5, 2014 Share Posted December 5, 2014 Vija aircraft engines- up to 160hp. Adapted from motorbike straight 4 cyl.... http://vija-engines.com/images/2010/ENG%20Produits-2010.html 1 1 Link to comment Share on other sites More sharing options...
bexrbetter Posted December 5, 2014 Share Posted December 5, 2014 ...every car and motorcycle engine I investigated, once fitted with redrive, radiator, etc, was heavier than a Jab 2.2. Well Rotax manage it but I agree it's daunting for a homebuilder, maybe your targets are too high? Don't forget that a 10 kg heavier package with a more efficient engine can at least yield a similar take off weight with less initial fuel required, although landing weight (low fuel) will still be heavier. Vija aircraft engines- up to 160hp. Adapted from motorbike straight 4 cyl....http://vija-engines.com/images/2010/ENG Produits-2010.html Ha! They are Suzuki Bandit 1200 engines as I mentioned! The prices are a joke but then, it is Europe. They would be around 80hp at 5000rpm. Link to comment Share on other sites More sharing options...
bexrbetter Posted December 5, 2014 Share Posted December 5, 2014 I HOPE you still COULD. They chiselled a bit of weight off the block and they are direct drive. Yay Pietenpol!!. Nev A Ford Model A engine is a pile of crap ... period. On what planet do you bag out modern bike and car engines as being unsuitable, then get all excited over a Model A engine. You are wrong about Porsche, they did not fail in aviation as an engine, the 80 odd sold are all still flying reliably and owners very happy, they decided to shut shop from a business perspective. I suspect the vile reception they got from the aviation press at the time from stupid old Journos pining for the past who can't accept progress at any level soiling Porsche's name, also had a lot to do with it. 1 1 Link to comment Share on other sites More sharing options...
facthunter Posted December 5, 2014 Share Posted December 5, 2014 I'm not forcing my ideas on anyone. People should have the choice if they want to build something with an "A" model Ford engine in it.. Weight is an issue because we have an arbitrary weight imposed on us. Most engines are crap Bex. You are setting the bar pretty high for yours when you continually bag other s ideas. . I don't have anything to prove, but I would rather you people produced serious evidence a bit beyond how fast these terrific engines you talk of GO. It's pretty irrelevant to an aircraft SITUATION . Has to be on the cutting edge of output for capacity eh!.. Well I disagree completely as relates to aircraft.. The Porsche engine was too expensive, but they build some nice stuff.. Nev 1 Link to comment Share on other sites More sharing options...
fly_tornado Posted December 5, 2014 Share Posted December 5, 2014 converting any bike engine but the bmw R series to aviation use is a complex process. 2 Link to comment Share on other sites More sharing options...
turboplanner Posted December 5, 2014 Share Posted December 5, 2014 I would no more fit that engine to a modern motorcycle than I would fit a modern motorcycle engine to an aeroplane. The engines cannot be optimum for BOTH Nev Good point, you are talking about the difference between an engine designed for intermittent loading vs an engine designed for constant loading. Motorcycles generally have low torque and use rpm to multiply that torque into high power (kW) Constant loading engines, as used in trucks and aircraft usually have higher torque with a lot less rpm required to reach the desired power (kW). The difference involves may components, starting with crank pin offset, so it's understandable that a motorcycle is not going to be exactly bullet proof in a constant load aircraft application. 1 1 Link to comment Share on other sites More sharing options...
fly_tornado Posted December 5, 2014 Share Posted December 5, 2014 the flipside is that bmw make 30000 of these engines every year so they can blew a few up testing them Link to comment Share on other sites More sharing options...
bexrbetter Posted December 5, 2014 Share Posted December 5, 2014 You are setting the bar pretty high for yours when you continually bag other s ideas. . Pretty low bar. It's you who's bagging the ideas here btw, read back. But anyway, what I am bagging is 1930's technology and that aviation hasn't moved forward. This whole thread exists due to the crap that keeps getting spouted about how reliable and simple air cooled, direct drive engines are - they aren't, they are rubbish, so bad that you need redundancy systems to back up the problems they cause. Might all be moot anyway judging by the amount of grey tops I see attending airshows and club meetings. Maybe some of you should stop spouting how awesome Spitfires and Tiger Cubs are and think about how to get new blood in, it is certainly foremost in my mind these days, my products are useless without a continuing fresh supply of buyers. Not just me either, I can quote Vans and Monnet for similar. Motorcycles generally have low torque and use rpm to multiply that torque into high power (kW) And? A long stroke engine uses a longer lever arm to multiply the torque and that incurs other various stresses. But here's the important part, a Rotax at 5800 rpm has the same piston speed as a Lycoming at 2800 and along with much smaller component weight, a Rotax at 5800 rpm will see no more stress than a Lyc will at 2800. The problem is people don't believe it, "oh I don't want one of those little high revving things, give me a "real" engine" - it is however a fact of physics. Good point, you are talking about the difference between an engine designed for intermittent loading vs an engine designed for constant loading. Prove it. A conrod or piston or crank etc doesn't give a stuff what it's application is, it only cares that the stresses offered to it and that those stresses do not exceed it's limits. It doesn't know if it's in a plane or a car or a truck. 2 Link to comment Share on other sites More sharing options...
Guest Andys@coffs Posted December 5, 2014 Share Posted December 5, 2014 perhaps Im on Bex's ignore list......go to the video that JimG posted and tell me why 300 hours of dyno testing is equivalent to 150,000miles.....As you say the component parts don't know....but yet an hour of full load on the dyno is somehow equal to 500 hours (assuming 100mph average....I wish!!) of normal use...... Or was it all Ford Marketing BS? Andy Link to comment Share on other sites More sharing options...
dazza 38 Posted December 5, 2014 Share Posted December 5, 2014 Since motorbikes have been mentioned and high RPM. The Honda CBR250 revs at 9000 RPM at 100 kph. It red lines at 20000 RPM. The are realiable and easily make 50 000 kilometres or more. With regular maintenance of course. 1 Link to comment Share on other sites More sharing options...
bexrbetter Posted December 5, 2014 Share Posted December 5, 2014 perhaps Im on Bex's ignore list......Andy No reason to have you on ignore, but for this topic it's very clear that it wouldn't matter what I said, you're mind is clearly made up. Since motorbikes have been mentioned and high RPM. The Honda CBR250 revs at 9000 RPM at 100 kph. It red lines at 20000 RPM. The are realiable and easily make 50 000 kilometres or more. With regular maintenance of course. Indeed, Yamaha and Kawasaki, maybe Suzuki, 250's run to 18,000. All the 400's (75hp) run to 14,000, 600's (100+hp) 12,000 etc etc. As you say, all day long with factory warranty. The Honda's sit on 10,000 rpm all day long on the Hwy at the legal 100 kmh. Link to comment Share on other sites More sharing options...
turboplanner Posted December 5, 2014 Share Posted December 5, 2014 Prove it. A conrod or piston or crank etc doesn't give a stuff what it's application is, it only cares that the stresses offered to it and that those stresses do not exceed it's limits. It doesn't know if it's in a plane or a car or a t Ok last 40 years in Australia - North American truck engines designed for constant loading at 110 km/ hr in overdrive through California, Arizona, Nevada, Texas etc when used on the same long distances in Australia have blitzed the European intermittent loading engines, just look at the market share. Link to comment Share on other sites More sharing options...
bexrbetter Posted December 5, 2014 Share Posted December 5, 2014 Ok last 40 years in Australia - North American truck engines designed for constant loading No, that's blatantly not true, I have learnt from this thread that only an aircraft engine exclusively and no other can survive constant loading. And now I also know not to fit a European truck engine to my plane. I'll leave it with you guys, this is merely a 'which side of the fence are you on' commentary going no where. The answer between which is best, air cooled, motorcycle or automotive is easy - the one with the big tits. 2 Link to comment Share on other sites More sharing options...
turboplanner Posted December 5, 2014 Share Posted December 5, 2014 Looks like you found a copy of Playboy while searching for the facts I mentioned. Link to comment Share on other sites More sharing options...
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