.


I was wondering if a diesel power plant on a back country plane might prove to be more of a hassle than it is worth ? Seems American Legend Aircraft Company out of Texas has mounted a Gemini 100 Diesel Engine from Superior Engines onto one their cubs. Installed weight for their Gemini 100 engine is < 200 pounds.



Cessna has announced that their C182 Diesel Skylane is on indefinite hold for now, although plans for a Diesel Cessna 172 may still be moving forwards. Source: “Cessna halts orders for diesel Cessna 182” http://www.aopa.org/News-and-Video/All-News/2015/May/14/Cessna-not-accepting-182-JT-A-orders

Even if most of the technical bugs were to be worked out, I was wondering if a diesel power plant would prove to be more of a hassle, if anything, in a back country plane, particularly one that sees a lot of cold weather? I don't know, which is the reason for this post.

Diesel Fuel Gelling


Given the high diesel compression, can a diesel be hand prop started?


Would injectors prove susceptible to frequent clogging or performance degradation due to fuel contamination?


Would costly additives be needed to help ensure optimal, trouble free engine performance?


How hard would it be to find qualified folks for service?

The last reason is the main reason for Cessna to pull the plug. All annuals - engine related work had to be take to one of only a handful of certified shops in the world. This seriously limited the marketability of these engines in certificated aircraft...

Remember these engines don't run primarily diesel. They are designed to run on Jet A. Diesel is not available on any airport (I've ever heard of) for anything other than the snow plows, trucks and lawn mowers...

You should reverse word the question: Is any engine requiring aviation specific fuel appropriate for a BCP Plane?

No. Lots of C180 on floats up here, hardly any C185, why? C180 can gas up at a boat marina, 185 has to find avgas somewhere. ACA was going to put a diesel in their Scout. 'Way more range, and outside the US there isn't any avgas anywhere. Lots of diesel.

Diesel/Jet fuel? I flew in Somalia in '93. Fuel for the truck, plane, generators, helicopters all came out of the same bladder.

I heard Volkswagen is bringing one to market in the US soon. [emoji48]

Diesel engines for airplanes are made to run on Jet A which is designed to flow at the flight level temperatures.

And virtually all Jet A is pre mixed with an additive designed to kill the bugs that can grow in those fuels.

MTV

Great replies..thanks to all..

I used the word "diesel" in the broad sense following somewhat the loose terminology being used by the manufacturers. I think the service and repair, when needed, could turn into a nightmare. especially in a remote location. In a tough SHTF situation in a remote location, a low compression carb equipped mogas powered engine in an experimental seems to give the most flexibility and least number of headaches.

Funny, I was at an airshow today and talking to a guy at the NTSB table. He personally owns an old Bonanza with a 6 cylinder fuel injected engine. One of the injectors went bad while flying over water in Alaska. He made it to Ketchikan, engine stumbling all the way, running it rich, and it scared the hell out of him he said. It turned out to be mosquito or something in the gas that had been in the tanks for a long time . It caused clogging of the injector. This gentleman was an NTSB guy that has investigated a lot of GA crashes. I spent about 45 minutes at the table learning a lot and getting the BeeJesus scared out of me.

Anyway, I posted the topic because I was curious about the state of the Diesel in 2015 re GA applications. I think I'll avoid injectors and diesel for now. Those experimental carb powered Bearhawks are just looking way fine.

YMMV.

mtv wrote:And virtually all Jet A is pre mixed with an additive designed to kill the bugs that can grow in those fuels.

MTV

A little AvGas in the jet fuel tank will kill those bugs.

.
AkJurnee wrote

A little AvGas in the jet fuel tank will kill those bugs.

The bug apparently had been dead for quite a while. He was convinced that the thing was in the tanks, and had jammed the injector as it was brought up in the fuel into the injector. I have never heard of a mosquito or bug actually in the gas and in the tank.

Mud dauber bees in pitot tubes yes.



Bugs in the gas tank is a new one for me. I am sure there are even far more weirder things out there yet about which I know nothing. Scary.

Denali wrote:

.
AkJurnee wrote

A little AvGas in the jet fuel tank will kill those bugs.

The bug apparently had been dead for quite a while. He was convinced that the thing was in the tanks, and had jammed the injector as it was brought up in the fuel into the injector. I have never heard of a mosquito or bug actually in the gas and in the tank.

Mud dauber bees in pitot tubes yes.



Bugs in the gas tank is a new one for me. I am sure there are even far more weirder things out there yet about which I know nothing. Scary.

I always thought there was a screen to stop debris?

.
A1Skinner wrote:

I always thought there was a screen to stop debris?

I am not sure about the screen thing. As I can best recall, he said it was an older Beech Bonanza Model 33. I can't recall any further specifics.

I think MTV is talking about the microbial variety of "bug" that can feed on diesel and ruin it.

Zane is right. That stuff is nasty.

As to fouled injectors, I picked up a new Cessna 185 in 1985. That thing fouled injectors for the first 200 hours in service, about every fifteen or twenty hours. I got really good at landing out, figuring out which injector was fouled (touch top of each cylinder....cool one is fouled), removing the offending injector, cleaning it and reinstalling. Got so I could do that in about fifteen minutes or less, start to finish.

The offending "stuff" was white fibrous material. It'd pack the fuel screen between inspections, but some of the very fine stuff would get through, and it doesn't take much to foul an injector.

We never figured out for sure where the stuff was coming from.....looked inside both tanks carefully, nada.

Later I talked to a retired guy who worked on the line at Cessna. He said that the person swabbing the tank sealant inside the fuel tanks left one of the white rags they use for that purpose inside one of the tanks, and what we were seeing was the fibers from that rag, as it came apart.

After about 200 hours, no more, and never had another fouled injector, in several thousand hours.

I wouldn't worry about fouled injectors. They are most assuredly not common.

MTV

Zzz wrote:I heard Volkswagen is bringing one to market in the US soon. [emoji48]

Grrrr... Freakin great car, my '14 Passat TDI. It will be anyway until CARB castrates it with a software patch.

Zzz wrote:I think MTV is talking about the microbial variety of "bug" that can feed on diesel and ruin it.

Same with semi trucks. Heard of fuel tanks having that problem and clogged filters.

There are junky old beat up diesels all over the world that people keep running. I don't believe that a diesel is a damn bit more complex than a fuel injected gasser and in many cases is a lot less so.
diesels also have a lot fewer moving parts, no ignition, and will continue to operate with all but the basic mechanical systems failed.
Modern cold start setups will enable starts without issue down to the point where gas engines also need help.
And to the last question about hand propping, I have used several small diesel motors that were hand cranked and the handle was a heck of a lot shorter than a prop blade.
I would have no worries flying behind a properly designed and set up diesel.

Denali wrote:Great replies..thanks to all..

I used the word "diesel" in the broad sense following somewhat the loose terminology being used by the manufacturers. I think the service and repair, when needed, could turn into a nightmare. especially in a remote location. In a tough SHTF situation in a remote location, a low compression carb equipped mogas powered engine in an experimental seems to give the most flexibility and least number of headaches.

Funny, I was at an airshow today and talking to a guy at the NTSB table. He personally owns an old Bonanza with a 6 cylinder fuel injected engine. One of the injectors went bad while flying over water in Alaska. He made it to Ketchikan, engine stumbling all the way, running it rich, and it scared the hell out of him he said. It turned out to be mosquito or something in the gas that had been in the tanks for a long time . It caused clogging of the injector. This gentleman was an NTSB guy that has investigated a lot of GA crashes. I spent about 45 minutes at the table learning a lot and getting the BeeJesus scared out of me.


YMMV.

Couple of thoughts before quickly dismissing fuel injection. There was a previous post on BCP of someone that found debris in their carburetor bowl; the difference was a complete loss of power rather than a rough running "5" cylinder engine. While a carb is simple, so is the continuous flow fuel injection in most aircraft engines and neither system is fail/fool proof, so it may not be accurate to assume the fuel injection is more likely to fail. And if it does, is it more likely to have a complete power loss? I'm not an engine guy, so not really trying to say one way or the other, just food for thought.

c170pete wrote:

Zzz wrote:I heard Volkswagen is bringing one to market in the US soon. [emoji48]

Grrrr... Freakin great car, my '14 Passat TDI. It will be anyway until CARB castrates it with a software patch.

I thought my 09 Jetta TDI was a great car until VW denied warranty coverage for the high pressure fuel pump that recently exploded. Only a $6k repair bill. Turns out in a random sampling of diesel from gas stations (by the NTSB), 6.2% of the sampled stations had fuel that fails to meet lubricity specs (<520 um), so when the test of the fuel in my car came back at 523 um, they denied covered because of contamination. To which I say, of course the fuel is contaminated, it has a few million tiny pieces of metal that used to be my fuel pump in it. 4 weeks into the saga and counting, but I guess they have bigger issues to worry about than 1 loyal customer. Sorry, I digress. This rant is related to this post only in that if the fuel does need additives, the cost is relatively low when you factor in the improved efficiency. Does that make it not BC suitable, i don't know, but combined with the cheaper fuel and improved efficiency, cost wise you'll still be way ahead even if you do use additives.

The single biggest issue to bringing a "diesel" aircraft engine to market is KEEPING it going. It costs HUGE money to certify an aircraft engine, and a couple of diesel engines have come and gone. If you'd bought an airplane with a Thielert engine, you'd be cursing them right now.

Cessna has worked to install and certify a couple different diesel engines so far, but not there yet.

So, I wouldn't touch one of the things at this point, just because, based on their track record to date, it's likely I could get left with an unsupported engine down the road.

The industry needs to get a functional, reliable diesel engine, and support it for some time and flight hours. Then, and only then is there much hope for a diesel aircraft engine for any use.

And, yes, fuel injection is incredibly reliable. Consider that virtually every modern auto engine is fuel injected. When was the last time anyone had to fiddle with the injection system on a car? Back when we used carburetors, I used to have to re-tune my pickup engine when I went to visit my folks.....I lived at 6500 msl, and they lived near sea level. I had to re-tune the carburetor coming and going on those commutes.

But, like anything else, if you put bad gasoline in your tank, you will have some problems.....carbureted or fuel injected.

MTV

mtv wrote: Back when we used carburetors, I used to have to re-tune my pickup engine when I went to visit my folks.....I lived at 6500 msl, and they lived near sea level. I had to re-tune the carburetor coming and going on those commutes.

I used to have to fiddle with the idle screws on my '69 F250 every summer and winter in Fairbanks.

FI is a wonderful thing. And EFI is very powerful.