gbigs Posted April 22, 2015 Report Share Posted April 22, 2015 Superior engines of Dallas, Texas has bought the rights to make the Gemini diesel engines that have been developed in Britain. The first engine is the supercharged 100hp three-cylinder version which is intended for the experimental and LSA market. It will burn Jet-A and have electronic control. This engine will compete directly against the Rotax 912iS but weight 20lbs more and get 20% better fuel efficiency. That would place it around 3gph at cruise. http://www.aopa.org/News-and-Video/All-News/2015/April/21/superior-introduces-diesel Link to comment Share on other sites More sharing options...
Anticept Posted April 22, 2015 Report Share Posted April 22, 2015 Oh hey, look at that! It's a OPOC engine! What's the dimensions of the thing? One of the reasons we don't see them in aviation is because they are VERY wide engines to account for the twin crankshaft design. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted April 22, 2015 Report Share Posted April 22, 2015 The article I read says it weighs 20% more than a 912, but then says it's 200lb. That's more than 20% more, even for the 912iS...more like 35%. And 60% more than a 125lb 912ULS. Link to comment Share on other sites More sharing options...
Doug G. Posted April 23, 2015 Report Share Posted April 23, 2015 Flying magazine says 20 lbs. heavier than a 912. Not sure which version they are talking about. What does the iS weigh? http://www.flyingmag.com/aircraft/lsasport/superior-launches-100-hp-diesel-engine Link to comment Share on other sites More sharing options...
FlyingMonkey Posted April 23, 2015 Report Share Posted April 23, 2015 Flying magazine says 20 lbs. heavier than a 912. Not sure which version they are talking about. What does the iS weigh? http://www.flyingmag.com/aircraft/lsasport/superior-launches-100-hp-diesel-engine My understanding is ~20lb more than a 912ULS, which would put it about 145lb. Link to comment Share on other sites More sharing options...
Jacques Posted April 23, 2015 Report Share Posted April 23, 2015 here is a 7 YEARS old news about the same engine... http://www.avweb.com/news/airventure/EAAAirVenture2008_TECNAM_GeminiDiesel_Tests_198459-1.html that says it all Link to comment Share on other sites More sharing options...
chanik Posted April 23, 2015 Report Share Posted April 23, 2015 They seem to substantially over-claim http://www.wingsforum.com/viewtopic.php?f=313&t=22131 Link to comment Share on other sites More sharing options...
Jim Posted April 23, 2015 Report Share Posted April 23, 2015 I was going to steer clear of this discussion, but I guess I can't. It's a 2-stroke, valveless opposed-piston diesel. Nothing new here. Fairbanks-Morse has been building them since the 30's. Early ones for railway applications had serious problems with cracked blocks early-on, but they've been reliable for a long time. I only mention the cracked blocks because for an opposed-piston design, the block needs to be pretty massive or it will crack. "Massive" and "Airplane" are two terms you don't often see together in general aviation. Junkers built a series of 2-stroke valveless opposed-piston diesels for aircraft applications. They worked poorly in bombers (sluggish and that cracked block thing) but well in airships. The English Napier company adapted the design into three sets of cylinders arranged into a triangle (Napier Deltic), which was one of the most powerful (and least successful) aircraft engine of it's time. The diesel fuel economy thing is intriguing, except that 2-stroke diesels are not as good a 4-strokes. That's why most railway service diesels are 4-stroke now. This all makes for a good academic discussion, but I don't think I'd want to fly behind one. Link to comment Share on other sites More sharing options...
Ian Posted April 24, 2015 Report Share Posted April 24, 2015 Some history of diesel engines for aircraft http://www.oldengine.org/members/diesel/Duxford/avrange.htm The Napier Deltic that Jim mentioned was originally built for the Royal Navy where it was pretty successful then apparently the US Navy bought them for use in the "Nasty Class" boats used in the Vietnam war, but perhaps their most interesting and longest lasting use was in railway engines creating a whole class of locomotives called the Deltic - some details here: http://atomictoasters.com/2011/01/the-napier-deltic/ While they were also adapted for aircraft use as far as I know they never got beyond prototype/test stage. Link to comment Share on other sites More sharing options...
Jim Posted April 25, 2015 Report Share Posted April 25, 2015 All good points, Ian. As a railroad brat and buff, I'd love to see and hear one of your Deltic locomotives. Link to comment Share on other sites More sharing options...
Runtoeat Posted April 25, 2015 Report Share Posted April 25, 2015 Ian, thanks for the Deltic link. I wasn't aware of the Deltic story in either boat or train and I enjoyed watching the videos and seeing and hearing the Deltic train engines whistling by at speeds at or near 100mph. Attempting to make diesels quiet in automotive applications was my job towards the end of my career. These engines certainly can make audacious noises and they are very good at tearing themselves apart if not maintained properly. I would love to be able to hear and feel a Deltic locomotive pulling up a grade while riding in the cab. Link to comment Share on other sites More sharing options...
Ian Posted April 25, 2015 Report Share Posted April 25, 2015 Well here you are guys - hop across the pond and take a ride behind a Deltic!! http://thedps.co.uk/category/railtours/ If you can't make it just have a browse of the site - some great information there Link to comment Share on other sites More sharing options...
Anticept Posted April 25, 2015 Report Share Posted April 25, 2015 Jim, With the technology of electronic injection and engine control, the gap between two strokes and four strokes seems to be closing. The power density of a two stroke is also insane, much higher than a four stroke. I'm still waiting to see how things turn out. I've seen an opposed cylinder opposed piston engine design where there is a single crank, and because of that they are able to use much lighter materials since the forces cancel out. Neat in design at least! Link to comment Share on other sites More sharing options...
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