But that will put Jaba out off bussiness. See what the future holds. Think Avgas will be around for a long time yet.
It will?
I think all of GA can disappear along with all the LAME's, the airlines get robots to fix their jets……..and it will have zero affect on my business. When all food production, water, sewage, power generation, road building, construction materials, mining, brewing, hospitals, <keep adding every industry sector you can dream of> and all the other industries in between disappear, then I am in trouble.
Just a quick look at Diesel Aviation engines and fuels, the calorific values, mass etc. For the comparison lets look at the pick of the Diesels so far, the SMA 230HP in the C182, and a typical GA engine the 260HP IO540.
Remember the Diesel burns Jet A, with a SG of about 0.81 and 128K BTU's / gallon. Avgas is about 0.71 and 114K BTU's / gallon. Lets for arguments sake assume tank volume is not an issue, because you can get more kg of Jet n the same tank and MTOW is, the Avgas KG=160.56K BTU's. The Jet A is 158.0K BTU. The Avgas has about 1.6% more per kg.
BSFC, the key diesel strength is impressive and the SMA quoted figures are 0.36 and compared to say a typical IO540 at 0.39-0.395 or even a TNIO550 at 0.385 you can say it is roughly 10% better. If you look at the lower compression engines such as many TC's then the BSFC gap is even greater.
I have not compared the SMA to any lower compression TC engines because while you could argue the SMA is turbocharged, and it is….it is not comparing real world apples with apples as it has to be TC just to match the N/A 540/550 as is the nature of the beast. In fact that is also its achilles heel.
Next is the weight of the power plant 455 lbs to 410 lbs, naturally the SMA is heavier, and this will affect the fuel payload assuming all other things are equal, as to what the net affect is will depend on the mission.
One advantage is the SMA will hold its HP up to 10,000' and that has a TAS benefit as the IO540 will be around 60-65% of its power at those kind of heights. The squared law comes into affect of course so it is not going to be quantum leaps faster. The C182 is about 11% faster for the same fuel flow, so there is a lot to like about it.
The downside is the cost, however the fuel is roughly 11-13% at the Shell pumps around Oz more for Avgas so that can have an impact when there is a 10% less burn. Makes the MPG about 24% more in dollar terms.
There is a lot to like, but this is a niche machine for one, and it is not going to be across the fleet any time soon. The STC process alone to convert the fleet is prohibitive for a start. Let alone all you folk who want EO's even with the STC.
The other down side is many GA pilots have had many intake leaks……and most never know about it (but that is another story) and this is my main concern. Look at the lovely picture here
http://www.smaengines.com/IMG/pdf/Fi...Engine_BAT.pdf and ask your self what happens with those pretty blue couplings when all is not 100% right. On your typical IO540 or even a TC/TN engine you have a manageable albeit non conforming engine. The SMA you have silence.
Pick ya poison!
Disclaimer: Numbers quoted are approximates and all is "back of beer coaster" calculation and analysis. In true PPRUNE tradition ;-)