KeithO

Just remember that the Automotive engine that this started out as was rated 90hp. There is very little on the engine other than head and block that is left over from the original engine. The crank and cam and fueling system, manifold, turbo etc are all new developments by Thielert (these guys earn most of their money building formula racing engines). The engine is an alloy casting and I think that for a reasonable TBO it is already maxed out. Also, there is no real "TBO". They talk about TBR (time before replacement). When the time is up, the engine is replaced complete. No components are overhauled at all. Very much like a turbine engine, except that TBR applies to modular components, so one does not neccersarily have to replace the whole engine in 1 go. The fuel load for a given range will be a lot lower than for a similar power gas engine, simply because the burn rate is so much lower. So in an apples to apples comparison, a gas powered airplane would always have to carry a heavier fuel load that one equipped with the Thielert diesel. Jet A and Low Lead fuel are both taxed a lot less in the USA than in Europe. The low lead fuel is very highly taxed and in low supply in Europe, thus they have great economic benefits in that market when using diesel instead.

Agreed that right now the prop is only being sold for the 80hp Jab powered "mini Spitfire", but it is still intriguing for the LSA class, since it has no cockpit controls. There is an english manual in PDF format that I will attach. There are some fairly detailed images in the PDF file. Manual_SilentR1_61V3.pdf

While a consciencious person may do reasonably well trying to keep his equipment in good shape when the means prevent under cover storage, there is no doubt that a lot more work is required compared to what will be needed if properly protected. One example was a honda motorcycle I had when I was younger and really poor. I bought it from a company who had a fleet of them and they were always parked inside at night and when the riders were not out making deliveries they were shining up the chrome. Well, I didn't have covered parking for the next 4 years. The wind blew constantly, so the thing was covered in dust anytime 5 minutes or more after it got a wash. Washing the plexiglass fairing was a major problem, since it was basically impossible to flush off all the grit before going over it cautiously with a sponge and wash/wax to try to get it clean. I was living in a marine environment, so there was salt around pretty much every day of the year and frequent morning dew that had to be cleared to see through the fairing. Well, after the 4 years, the thing looked like crap. The chrome plating would exacerbate corrosion as soon as there was the tiniest break in the surface. The aluminum forks and motor had developed a blotchy appearance with the color darker on the least oxidized areas and lightest in the most oxidised areas. The chromed wheels were a mess of chrome with spider web veins of brown rust. The fairing had swirls upon swirls of fine scratches that had developed from repeated washings, even though I really tried to avoid causing any damage in the first place. My comments regarding cockpit temperature come from present experience in the midwest. Even though I use a reflective shield in the windshield in summer, I still have the outgassing problem on my chevy's interior and it is a ***** cleaning off the deposit on the inside of the windshield. The coating forms a light haze that is a minor annoyance during the day but a major annoyance during damp conditions, since condensation appears to be triggered by the coating on the inside of the windshield and is far more problematic when present than after it is cleaned. I have a cloth interior that has not been treated with any kind of chemicals (other than what they do at the factory). The comments regarding the windshield come from observations of the training fleet at JCC flight school and my late boss's Bonanza. I have personally found the poor condition of windshields on $70-150k airplanes to be totally inexcusable. I have to say I have not seen this on experimentals and maybe that is because a builder would just as soon replace the canopy if it was in bad shape, but owners baulk at the cost of having this done on their certified airplanes. At flight schools, students are typically not allowed to touch the windshield, for fear that they would damage it (which may be justifiable in many cases). I'll be honest and say that I don't possess an airplane at present, but I certainly would want to keep one indoors when I can afford one. In Europe where hanger space is a virtual impossibility many folks use custom built trailers and have folding wings for this exact reason. I'm not by any means suggesting that anything is going to fall apart, but something parked outside will get its usefull life "used up" faster than if better protected. Now if one realistically has 20 years of active life ahead of you and a "new" airframe and priorities elsewhere, then that is what works for you.

There are other, more significant problems with parking a bird outside in the elements for years. The cockpit will get way up there in temp from the absorbed solar heating. Paint and composite and seat cushions will outgas coating the inside of the canopy with a hard to remove film. The canopy will craze and crack from the thermal stress. You will have a nice gritty grinding paste covering the outside of the airframe at all times. The engine will attract condensation from sitting out and the daily temperature and humidity swings. Dissimilar metallic joints will rapidly corrode (in relative terms). UV will bleach out everything it can get to. An airplane is never really cheap, so leaving it out is a pretty desperate thing to do, which is something more commonly seen at very busy hubs where hanger space is basically unaffordable or unavailable. Even the "roof only" hangers are a substantially better deal than no hanger at all. Of course I have a natural aversion for large collections of people (cities) so this is less of a problem where I live. In fact, the demand for hanger space is so low that many of the former hangers at Reynolds field in Jackson are now warehouses for local businesses.

Take a look at this website: http://www.silence-aircraft.de/ Unfortunately it is a flash website so I can't get the exact hyperlink for the V prop page, but click on the US flag on the top right to get english and then on the "Propeller" tab. It seems a pretty neat prop. It has a spinner with vanes that generates sufficient power to drive the electronics without needing slip rings. It is fully automatic and can be programmed by jumpers (bridges on the circuit board). It defaults to fine pitch for safe landing or takeoff if the electonics take a dive. And it costs a mere 3600 Euro. Compare that to an MT prop... That is of course the only certified option for any long derivative, tested extensively by the round the world fliers (one swiss air pilot has done it 3 times in his long).

Marc, the proposed design is about 1/4 of the eclipse not half. Furthermore, it is a single engine design and assuming the operational profile is similar, it should have a similar fuel burn as one of the Eclipse motors. A piston twin would tend to have about double the fuel burn compared to a single and of course it will weigh more and should have more payload. I didn't think this was a difficult concept.

Agreed on the 181 gal for 2 engines, thus 90.5 gal for 1 engine. For 1100 nautical miles, that works out to 12.14 nmpg *1.150779 (to get statute miles) = 13.97mpg ( I didn't work out an exact number before and I used a slightly different density to you) Isn't it incredible that this is the fuel economy a bunch of people get driving their truck or SUV at 70-75mpg ? I figure that for a significantly smaller airframe the cruise speed will be higher. Looking at some rough numbers yesterday using a demo version of Drag Estimator it seems like 500kts could be achievable on 900lbs of thrust at 20000 ft, but there is not enough info available on fuel flow mapping for the turbine to make a properly educated guess at how this will pan out. It seems like only OE airframe manufacturers are privy to detailed performance info on the turbines. No set of specific fuel consumption vs thrust curves are available for any altitude or any speeds.

I had a look at fuel burn for the Eclipse and for long cross countries it worked out to be approximately 0.5lb/mile per engine. That is with 2 Pratt & Whitney 610F 900lb thrust turbofans. Working this back to miles per gallon it was 13mpg or at 370kts it s 31.1 gal/hr. Admittedly, a smaller aircraft would generate less drag than half of the eclipse or would be cruising faster. Based on these numbers, at the proposed 300kg fuel load that would equal 96.5 gal or less than 3 hours endurance to an empty tank @ 560kts.

I'm comparing it to an F106A. Issues I see are cost for the turbine. Willingness of the turbine manufacturers to work with a project like this. I also tried to get an idea on fuel burn for the single engined VLJ's that abound and the only one I could find was the Diamand Jet which calculated out to 6mpg. Somehow the advantage in fuel efficiency for the at least $250k investment in the modern turbines isn't becoming clear to me. Has anyone found any info published on fuel burns for the new generation of turbines ?

http://www.smartfish.ch Apparently it is called the "Smartfish". Personal jet for 2 with the following specification: Length 6.0 m Wingspan 4.7 m Aspect ratio 1.7 Height 2.0 m Max. Takeoff weight 1'000 kg Zero fuel weight 400 kg Fuel capacity 300 kg Payload 300 kg Takeoff and landing distance 700 m Vso 125 km/h Vne Mach 0.85 Take note of the VNE of Mach 0.85 !!!! It looks like landing the beast will be just 1 step down from the shuttle "glider".. Apparently a Concord like AOA of 25 degrees is required to achieve the close to 70mph stall speed. There is a very slick marketing video here: http://www.smartfish.ch/art/SmartFish_Design_10.wmv Does anyone know how much the original EJ22 engines were meant to be for the Eclipse ? Is it possible that it could be in the $100k range ? This kind of machine is simply dead without a suitable powerplant.

I recently wrote to Eco motors, a company in Germany who are building complete 80 and 100hp engine packages based on an automotive turbodiesel engine. The engines are 4 cylinder turbodiesels with common rail injection, along with the automotive style ECU. Both engines are 1.4L with the difference being the boost level (2.0 vs 2.4 bar) Drive to the prop is via a geared reduction drive with its own independant oil bath and 1.67:1 reduction. In the photos the reduction drive looks rough, but it may be the prototype version. Certainly, getting in the air with an experimental aircraft with an experimental engine is a big deal in Germany. I lived there and investigated this subject at length. Even if I had built a plans built (or even a kit airplane) I would have to do a static load test on all flight surfaces prior to getting an airworthiness ticket. Picturs of this process can be seen on many of the home pages of the German homebuilders. The web page is here: http://www.eco-motors.com/Index.htm Technical info here: http://www.eco-motors.com/Products.htm Contact details here: http://www.eco-motors.com/Contact.htm In their current offer, found here: http://www.eco-motors.com/images/Downloads/Eco-Motors-General-Info.pdf they are asking <10k Euro for the 80hp motor which contains the following: Basic Engine Kit Base aluminum diesel engine, common rail injection system, fuel pump, fuel filter,electronic control unit, reduction gear unit, turbo charger, air intercooler (Eco-100 only), oil reservoir, engine wiring harness, all sensors, device to readout and erase engine diagnostic state The 100hp version adds the intercooler and takes the price up to <12k euro The holding company is: MARAGU GmbH Seinsheimstrasse 9 D-97209 Veitshoechheim, Germany I have attached pictures of the left and right side views of the engine as well as the company flyer. I asked the question whether the engine would be sold in the US. This is the answer I got below: From: info@eco-motors.com To: "Keith Olivier" <classified> CC: "Martin Stürzenberger" <martin.stuerzenberger@schaeffler.com> Subject: RE: 80 & 100hp aviation turbo diesel engines Date: Tue, 11 Dec 2007 22:53:27 +0100 Hello Mr. Keith, Yes we are also convinced, that our engine class ideally fits to the LSA class within the US. To be clear, yes we also deliver the engines to the US, but for liability reasons, we have to make clear to the customers, that our engines are not certified aircraft engines. Before buying the engine, the customer has to sign and send back a document, where he confirms and accepts this non certified state explicitly. Would be nice to hear from you again Best regards Dr. Rainer Hirn

See the attached pdf. Last few pages have the pictures. Certainly the con rod is radical, but the claim that the bearings are always loaded in compression at any operating point is apparently true for a 2 stroke. At the top of the stroke you have all of the cylinder pressure and at the bottom the inertial load of the decelerating piston and con rod. Wilksch apparently use a ball end on the con rod at the piston end, which is similar, but much easier to machine that the Zoche idea. Regular gudgeon pins and bushings apparently cannot be adequately lubricated for this service (diesel 2 strokes). Zoche diesel main filing DE9007543U1_29.pdf

Meanwhile the web sites are down, but these are spark ignited diesels. They have a normal gasoline compression ratio (9-10:1 as opposed to 18:1 for compression ignition). The result is that while they may run on diesel, they are not really comparable in efficiency to a normal diesel. The reason these engines were developed is the US military's "1 fuel" initiative. They basically want everything to run on Jet A to ease logistics.

Lynn, you are assuming an uneven number of cylinders, like what is used for conventional radials (4 strokes). With 4 strokes that fire every other rotation, an uneven number of cylinders is typically chosen. Since a 2 stroke fires on every revolution, one can use an even number of cylinders and balance the reciprocating masses almost perfectly by positioning the cylinders / pistons directly opposite one another. See the pictures on this page: http://www.zoche.de/specs.html There is nothing conceptually wrong with their design. There are many air cooled diesel truck engines used in desert environments. As can be read in this abstract http://www.sae.org/technical/papers/951047 Deutz, one of the most respected engine manufacturers in Europe, has been building air cooled diesel engines for some time. They are also popular in some of the coldest parts of the world (russian tundra). I personally have seen them in operation in Namibia and Angola in very harsh conditions, ambient temperatures up to 113F, soft sand in low range for days. 2 stroke diesels are unlikely to make it in passenger car applications because of the low emissions requirement and also because the engine dynamic (runs at half the RPM of a conventional diesel) just does not fit what most people want. But for aviation, a max RPM of 1800-2000 rpm is considered perfect for direct drive and low prop noise. Not surprisingly, GA has not developed it with much gusto. Wilksch Airmotive has started production of their inline 2 stroke diesels, but because of currency issues (high value of the british pound vs devalued $) their engines are quite expensive for this market. Wilksch does have a conventional mechanical injection pump, so this does severely limit their efficiency but for the benefit of not requiring sophisticated engine controls. Those in the market who have succeded (Thielert / Centurion) use modern common rail injection with an ECU. There is also this outfit: http://www.eco-motors.com/Products.htm who are just getting going with production. One can download the quote here: http://www.eco-motors.com/images/Downloads/Eco-Motors-General-Info.pdf Basically a 100hp engine will run $17 600 at present exchange rates (without radiator, prop, spinner, engine mount etc). 1/3 less fuel consumption than a Rotax 912 for 50lb higher weight.

Lynn: You need to get your facts straight regarding 2 stroke diesels. If you check out this page: http://en.wikipedia.org/wiki/Specific_fuel_consumption It contains a table that shows that a current (2006) marine 2 stroke diesel manufactured by Wärtsilä-Sulzer holds the record for best specific fuel consumption @ 163 g/kWh as compared to 300g/kWh for a gasoline engine running at peak efficiency. To give a typical example: If you were to run an O-235 at 100hp in cruise and you achieved a typical 300g/kWh efficiency, this translates to a fuel burn of 9.3 gal/hr. In reality many folks require less than 100hp at cruise, so they may use less fuel. If you had a scaled down version of the marine diesel, the consumption would be 5.05 gal/hr under exactly the same conditions. This leaves only considerations relating to the modern execution of the design to achieve acceptable weight and compactness (which were achieved by Zoche) to provide a viable powerplant. The failure by Zoche to deliver is saddening, because we have all seen examples of the misuse of government funding to develop technology which the government allows the development contractors to retain patent protection on, even after they subsequently fail to deliver the technology to the marketplace. This is exactly what happened in the case of the GAP projects. No diesel in sight and the small turbines developed have a price tag of $250k each, despite government funding of the development.

I'm guessing someone bought the rights to supress the concept. They did have running and fully operational engines prior to progress halting. It was a family business and I am just guessing that they got an offer that they couldn't refuse.

Something I have not yet seen mentioned is surviveability of an off field landing. I think the RV10 will win that one hands down. The high landing speed and the small wheels with high center of gravity (due to pusher prop clearance) tends to mean that you would be very lucky indeed to have an damage free landing on anything other than a long stretch of asphalt. I know that a lot of people have walked away from off field landings but in virtually every case the airplane was destroyed. It is the primary reason I have hesitated to start building. A 3 wing design with front mounted engine would most likely be the most forgiving configuration, but aerodynamically the most complicated to execute. It does away with the pusher prop issues, alows flaps for better approach speeds, shorter landing gear. Of course the view is spoiled somewhat and the cabin is in the prop wash so it will be noisier. 3 flying surfaces means a tail, so the wing can be straight (improves some of the stall characteristics). Composite construction damps vibration better without the drumming and "oil canning" of sheet metal, so the "quality" of the sound inside will be superior. And properly executed, composite can be very strong and does not have to shatter on impact. I'm still sitting on the fence as you can see....

Right at the time that the company was launching the kits, Midwest (who built the rotary engines) was purchased by Diamond who immediately took the engines off the market. It is possible that Diamond continues to build the engines for defense contracts exclusively. This is about the same as what appears to be going on with Deltahawk and their diesel engine. There is no directly substitutable replacement engine, since the midwest engines were watercooled and very compact. It is almost the same deal as the BD5 except that the midwest engine had in fact been sold for years before Diamond pulled the plug. The result is that the airframe would more than likely need extensive changes to accomodate a different powerplant. Here is a link to Diamonds website: http://www.diamond-air.at/diamondengines+M52087573ab0.html but you will notice that the 100hp engine is absent and I have not heard of the smaller engines being sold (they would be great competition for Rotax in the light sport arena).