Diesels aren't perfect

[lancie00]

I've heard a lot of talk about diesels in airplanes. I'm here to say that they aren't always that great. We just noticed a miss in our combine with a diesel and after getting it to the shop, it broke a valve, dropped it on the piston, scratched the cylinder walls, and dinged up the head. Estimate is $18,000. They're tough but not indestructible.

Can I start a go fund me page?

 

[Ted]

The diesel in your combine is probably also significantly heavier (read: tougher overall construction) than the diesels used in piston aircraft.

The real benefit of diesels in aircraft is the ability to use Jet A and get off of 100LL. In reality that's not that big of a deal in the USA.

 

[Kenny Phillips]

The diesel in your combine is probably also significantly heavier (read: tougher overall construction) than the diesels used in piston aircraft.

The real benefit of diesels in aircraft is the ability to use Jet A and get off of 100LL. In reality that's not that big of a deal in the USA.

Plus they are cheaper to operate, as Jet A is more energy dense, is often much cheaper, and the engines have higher thermodynamic efficiency. They'll become a big deal unless someone comes up with an unleaded avgas that will work in most engines.

 

[Dan Thomas]

Plus they are cheaper to operate, as Jet A is more energy dense, is often much cheaper, and the engines have higher thermodynamic efficiency. They'll become a big deal unless someone comes up with an unleaded avgas that will work in most engines.

They'll become a big deal once they cost little more than the gasoline engines we have now. Currently, they cost around three times as much.

 

[Spring Ford]

I LOVE this idea.

https://deltahawk.com/engine-specifications

However, they have been promising Certification "next year" for over a decade (as I recall).

Two stroke diesel.

NO -
camshaft or drive, followers, pushrods, rockers, valves, guides, springs, ignition system, separate cylinder heads.

However, it can't feed itself with air. Don't worry, the largest ship's engines work quite like this too.

SO -
You get a "supercharger" but it is really just a crankshaft driven air pump to feed the engine with air.

And -
A turbocharger which is essentially a turbo-normaliser but if the supercharger self-destructs in flight the turbo will keep the engine running.

It will run with one of the Supercharger or Turbocharger operating. However at reduced power, at least if at altitude. For starting you have to have the supercharger.

Seems interesting.

No engine electrics whatsoever.

 

[bnt83]

I'm not in-lust with new engines as the old "on condition" ones we have now will stay far cheaper than new type certified ones which manufacturers will keep a tight grip on and likely carry mandetory hourly and calender life limits. Just look at Williams turbine engines how those are managed.

For those who don't know only Williams can overhaul them, they have you cornered wheather or no you're paid up and on the program.

 

[benyflyguy]

I've heard a lot of talk about diesels in airplanes. I'm here to say that they aren't always that great. We just noticed a miss in our combine with a diesel and after getting it to the shop, it broke a valve, dropped it on the piston, scratched the cylinder walls, and dinged up the head. Estimate is $18,000. They're tough but not indestructible.

Can I start a go fund me page?

Yea. But only for your emotional losss.

 

[bnt83]

I've heard a lot of talk about diesels in airplanes. I'm here to say that they aren't always that great. We just noticed a miss in our combine with a diesel and after getting it to the shop, it broke a valve, dropped it on the piston, scratched the cylinder walls, and dinged up the head. Estimate is $18,000. They're tough but not indestructible.

Can I start a go fund me page?

What combine do you have?

There are pictures all over of much beefier engines than our aircraft piston engines, like deisel semis, with similar failures.

 

[Ted]

Plus they are cheaper to operate, as Jet A is more energy dense, is often much cheaper, and the engines have higher thermodynamic efficiency. They'll become a big deal unless someone comes up with an unleaded avgas that will work in most engines.

I'm not too worried about fuel for planes currently using 100LL. Yeah, they're working on it, but even the EPA has acknowledged it's not much of a priority for them.

Diesels have been around for over a decade in piston aircraft now and yet you still see very few aircraft being produced with diesels. 10 years ago many thought they would take over all new aircraft sales, and that's not been the case. They'll become more relevant eventually, but it's going to take a while. It might happen before I retire.

 

[tspear]

I'm not too worried about fuel for planes currently using 100LL. Yeah, they're working on it, but even the EPA has acknowledged it's not much of a priority for them.

Diesels have been around for over a decade in piston aircraft now and yet you still see very few aircraft being produced with diesels. 10 years ago many thought they would take over all new aircraft sales, and that's not been the case. They'll become more relevant eventually, but it's going to take a while. It might happen before I retire.

Diamond sales are all Diesel (for now, avgas is hold). Piper has added a couple of Diesel versions which per sales people are doing well.


Sent from my SM-J737T using Tapatalk

 

[Grum.Man]

The thorn in every new engine technology is that it cost more, or at least as much than what it's trying to replace. Very few people are willing to take that plunge unless there is a significant advantage. For something new to really take hold it will require the manufacturer taking a loss for a few years until the marketplace adopts it. Since most people aren't in the business of charity, this is unlikely to take place. The price of modern car engines has gone up dramatically over the years with the new technology. So much so that by the time you engineer and manufacture a gear box you have pretty much reached TCM or Lycoming money.

There was a guy at OSH showing off his new engine design that caters to the 300+ HP club. Turbo normalized and could run off ethanol gas in a compact light weight package. There was barely a spot to stand around the guy until someone asked the 70k question. As if in unison the whole crowd let out a chuckle and started to disperse.

I'm patiently waiting on a 300 hp turbo prop that cost less than an IO-550

 

[lancie00]

What combine do you have?

There are pictures all over of much beefier engines than our aircraft piston engines, like deisel semis, with similar failures.

It's a John Deere 9550. Similar to this one.

 

[Ted]

Diamond sales are all Diesel (for now, avgas is hold). Piper has added a couple of Diesel versions which per sales people are doing well.

Correct, it's coming along and it's greater than zero. But ultimately the total market penetration is perhaps only slightly better than in the years when Thielert first started peddling their engines, and if you look, today's engines look pretty similar to what Thielert was selling (with some technological improvements).

10 years ago the prediction was that everything would be diesel by now. That's proven to be completely wrong. Thielert's failures made it harder for diesels to penetrate the market, since that's made people realize that these engines aren't perfect.

Let's look at some aircraft that don't have diesels in them (although may at some point). Piper M350, Cirrus (all), even Cessna got rid of their diesel offerings and they were the most gung-ho on it from the beginning (other than perhaps Diamond).

Cape Air is investing in a bunch of Tecnam P2012s with the Lycoming iE2 in them, not with diesels.

And 99+% of legacy piston aircraft still have spark ignition engines, very very few diesel conversions.

Like I said, it's going to take a while for diesels to become relevant in the market. But it might happen before I retire.

 

[Grum.Man]

The engine in my Chevrolet Cruze diesel would be perfect for an airplane. It's all aluminum and makes 240 lb/ft of tq at like 1800 rpm. I would hate to know what a new 1.6 TD cost though.

 

[bnt83]

It's a John Deere 9550. Similar to this one. View attachment 68434

I hope you got a respectable number of hours out of it before it broke. :-(

 

[Ted]

The engine in my Chevrolet Cruze diesel would be perfect for an airplane. It's all aluminum and makes 240 lb/ft of tq at like 1800 rpm. I would hate to know what a new 1.6 TD cost though.

Torque is pretty much irrelevant in an aircraft, it's horsepower that matters since that determines how fast you'll go (with a few other factors, of course). I did a quick search on Google and it said the Cruze Diesel makes 137 HP @ 3750 RPM, which is more or less in line with the early Thielert 1.7s (no surprise given the very similar configuration). So you're still looking at needing a gearbox of some sort and being a power reduction in a 172 vs the existing Lycoming, which were two of the challenges that have always existed. Sure you could turn the boost up, but you're still going to have a hard time making the necessary horsepower at direct drive RPM. The gearbox gets complicated because your torsional vibrations get pretty high. That was why Thielert went with the clutch, which had to get replaced regularly. Diamond seems to have figured it out better.

Plus you have to figure out the dual channel FADEC and get fuel system components that are designed to handle the (lack of) lubricity of Jet A vs. diesel, design your wiring harness and pass all DO-160 tests, etc. etc. etc. Not exactly a bolt-in proposition.

So, ultimately, I'm not seeing anything that's changed yet to make the equation noticeably different than a decade ago.

 

[tspear]

Correct, it's coming along and it's greater than zero. But ultimately the total market penetration is perhaps only slightly better than in the years when Thielert first started peddling their engines, and if you look, today's engines look pretty similar to what Thielert was selling (with some technological improvements).

10 years ago the prediction was that everything would be diesel by now. That's proven to be completely wrong. Thielert's failures made it harder for diesels to penetrate the market, since that's made people realize that these engines aren't perfect.

Let's look at some aircraft that don't have diesels in them (although may at some point). Piper M350, Cirrus (all), even Cessna got rid of their diesel offerings and they were the most gung-ho on it from the beginning (other than perhaps Diamond).

Cape Air is investing in a bunch of Tecnam P2012s with the Lycoming iE2 in them, not with diesels.

And 99+% of legacy piston aircraft still have spark ignition engines, very very few diesel conversions.

Like I said, it's going to take a while for diesels to become relevant in the market. But it might happen before I retire.

In 2017, there were 1075 new piston planes delivered/sold per GAMA. Of that total 130 were Diamond, and 122 would have been Diesels (assumption all DA-40, DA-42, DA-62 are Diesel, DA-40 XLT avgas version suspended production in late 2016 from what I can tell). Diamond has only converted about 12% of the new airplane market. That is a good start, but by no means is it taking the world by storm!
What is interesting though is Diamond and Piper have both won a large number of fleet sales in 2018. In both cases, the fleet sales were Diesel engine variants, even sold in the USA.

I think Cessna bailed on Diesel way to fast, and also tried to take it to high up the ladder in terms of planes. The reality is the CMI (was Thielert) and AE300 (Diamond Austro) are the only "proven" engine programs that continue to make headway. The SMA engine just does not have the numbers/experience for a company like Cessna to bet on it. As much as owners clamor for the new tech, they really do not like to purchase it!


Tim

 

[tspear]

So, ultimately, I'm not seeing anything that's changed yet to make the equation noticeably different than a decade ago.

Actually, there has been a fair amount of change for DA-42/DA-40 airplanes. Gear box replacements have gone from 300 hours, to 600 and higher (dual mass flywheel), TBO/TBR have been extended....
There was a pretty good analysis by a Diamond dealer on all scheduled MX costs from purchase to TBO/TBR for the range of Diesel engines on the DA-42. The engine costs alone to cover the MX on the oldest 2.0L engines (does not include the overhaul/rebuild) starts around $51 per hour for the oldest engine, to $44 for the second generation, and $24 for the newest. http://www.greatlakesdiamond.com/hourly-engine-reserves-for-da42/

The end result, a new DA-42 with the latest generation of engines actually beats an SR-22 on OpEx basis, and flies five to ten knots faster. Ten years ago, the SR-22 was faster by five knots, and a good $50 bucks an hour cheaper to operate. The reason I am in an SR-22 now is a fifteen year old DA-42 does not exist, and a ten year old DA-42 is 100K more expensive than a 10 year old SR22. SR22 costs per hour have basically been static for the past fifteen years. While the Diesel engines have slowly come down. This is why I think some flight schools and charters are starting to make the switch.

Tim

 

[mondtster]

It's a John Deere 9550. Similar to this one.

Which engine?

 

[Ted]

In 2017, there were 1075 new piston planes delivered/sold per GAMA. Of that total 130 were Diamond, and 122 would have been Diesels (assumption all DA-40, DA-42, DA-62 are Diesel, DA-40 XLT avgas version suspended production in late 2016 from what I can tell). Diamond has only converted about 12% of the new airplane market. That is a good start, but by no means is it taking the world by storm!
What is interesting though is Diamond and Piper have both won a large number of fleet sales in 2018. In both cases, the fleet sales were Diesel engine variants, even sold in the USA.

I think Cessna bailed on Diesel way to fast, and also tried to take it to high up the ladder in terms of planes. The reality is the CMI (was Thielert) and AE300 (Diamond Austro) are the only "proven" engine programs that continue to make headway. The SMA engine just does not have the numbers/experience for a company like Cessna to bet on it. As much as owners clamor for the new tech, they really do not like to purchase it!

Calling the Thielert "proven" I think is being generous at best. It's been around for a while, but it's still been slow to take after the initial failures. SMA had been trying to sell their diesel for a long time.

But your points above (especially the highlighted part at the end) just illustrate my point. Diesels at this point have a long ways to go. A fleet purchase can justify it because of some good pricing, economics, and the ability to say "We have internal maintenance so we know we'll have people who can fix it." That's a much harder sell to Joe Q. Pilot who doesn't want to get stuck in BFE where the local A&P doesn't have a clue what to do on the diesel, nor the tools, when it gets a "Check Engine" light.

Actually, there has been a fair amount of change for DA-42/DA-40 airplanes. Gear box replacements have gone from 300 hours, to 600 and higher (dual mass flywheel), TBO/TBR have been extended....
There was a pretty good analysis by a Diamond dealer on all scheduled MX costs from purchase to TBO/TBR for the range of Diesel engines on the DA-42. The engine costs alone to cover the MX on the oldest 2.0L engines (does not include the overhaul/rebuild) starts around $51 per hour for the oldest engine, to $44 for the second generation, and $24 for the newest. http://www.greatlakesdiamond.com/hourly-engine-reserves-for-da42/

The end result, a new DA-42 with the latest generation of engines actually beats an SR-22 on OpEx basis, and flies five to ten knots faster. Ten years ago, the SR-22 was faster by five knots, and a good $50 bucks an hour cheaper to operate. The reason I am in an SR-22 now is a fifteen year old DA-42 does not exist, and a ten year old DA-42 is 100K more expensive than a 10 year old SR22. SR22 costs per hour have basically been static for the past fifteen years. While the Diesel engines have slowly come down. This is why I think some flight schools and charters are starting to make the switch.

All of those are pretty minor changes really. You're still talking about TBR rather than TBO on engines, the mandatory gearbox replacements at insanely low hours... all things that a fleet operator with internal maintenance could potentially work with given some bargaining power, but is unappealing to the individual unless that person wants to be the first one on the block.

We still have a long way to go. Legacy engines have a lot of issues as well, and I'm a fan of the diesels, but they're still a long ways from becoming truly relevant.

 

[Tantalum]

We just noticed a miss in our combine

That's a sample size N of 1.. in an operating environment that is only comparable to an application in an aircraft engine in the sense that they're ICE and not burning gasoline. The marine diesel in our boat has been abused since 1981 and the only care it gets is a yearly oil change, and the injectors cleaned every 5-10 years. The only issue we've ever had with it are damaged impellers from the salt water intake getting plugged with seaweed. But like others have said I am pretty sure the main advantage of diesel is the ability to burn JET A. Wasn't the TBO on the first few diesel aircraft engines very low?

I love the idea of running diesel engines in planes but I agree that their applicability is limited.. heavy, big, and much higher operating stresses. If you need to burn JET A I think your best bet is to go turbine. The DA-62 is an awesome plane.. but I don't think there is an applicable scenario where I would spend $1M on that (if JET A burning was my main deciding factor) when I could buy a turbine for similar or less money and get better performance. If I were to buy a DA62 it would for other reasons..

Jet A is more energy dense

YES!! This is exactly why I am skeptical that electric battery powered airplanes will ever be a legitimate means of air travel.. chemically you just can't get the same energy density into a battery.. I'm sure we'll get to a day where there are trainers with a 100-200 mile range, and similar short haul airliners, but I just can't envision a day where you have a Bonanza / 210 / Mooney / SR22 / hell B777 equivalent

Two stroke diesel

Totally.. 2 stroke diesel is where it's at. Really, 2 stroke in general

 

[tspear]

All of those are pretty minor changes really. You're still talking about TBR rather than TBO on engines, the mandatory gearbox replacements at insanely low hours... all things that a fleet operator with internal maintenance could potentially work with given some bargaining power, but is unappealing to the individual unless that person wants to be the first one on the block.

We still have a long way to go. Legacy engines have a lot of issues as well, and I'm a fan of the diesels, but they're still a long ways from becoming truly relevant.

Actually Continental (was Thielert) makes you sign a waiver if you want to go past TBR on the CD-135/CD155 engines (this is based on statements from Diamond shops, and a Continental rep).
For the AE300 and AE330, it has always been a TBO.
All told there are four diesel engine variants on the DA-40/DA-42.

• CD-135 1.7L. Very rare, the original Thielert engine
• CD-135 2.0. Most common Thielert engine, there are three generations of this engine. Each one has decreased the MX cycles.
  
• CD-155 2.0S. More powerful version of the latest CD-135 engine. Requires extra cooling. Two STCs available for install on DA-42. One via factory, one via private individual who did it and now resells it via at least one Diamond Service Center.
• AE-300 Diamond's version of the CD-135. Significant differences. Iron block instead of Aluminum (heavier, longer life, lower cost), torsional flywheel instead of clutch, more power (168HP vs 135HP)....

The AE-330, is the more powerful version of the AE-300 used on the DA-62. New ECUs, more radiators....

Tim

 

[mondtster]

Torque is pretty much irrelevant in an aircraft, it's horsepower that matters since that determines how fast you'll go (with a few other factors, of course). I did a quick search on Google and it said the Cruze Diesel makes 137 HP @ 3750 RPM, which is more or less in line with the early Thielert 1.7s (no surprise given the very similar configuration). So you're still looking at needing a gearbox of some sort and being a power reduction in a 172 vs the existing Lycoming, which were two of the challenges that have always existed. Sure you could turn the boost up, but you're still going to have a hard time making the necessary horsepower at direct drive RPM. The gearbox gets complicated because your torsional vibrations get pretty high. That was why Thielert went with the clutch, which had to get replaced regularly. Diamond seems to have figured it out better.

Plus you have to figure out the dual channel FADEC and get fuel system components that are designed to handle the (lack of) lubricity of Jet A vs. diesel, design your wiring harness and pass all DO-160 tests, etc. etc. etc. Not exactly a bolt-in proposition.

So, ultimately, I'm not seeing anything that's changed yet to make the equation noticeably different than a decade ago.

Ahh, the old horsepower vs torque debates...

I'm sure you know this but turning up the boost will effectively do nothing to help matters on its own. Since the diesels are almost always run in a condition where fuel is limiting power you really need to add fuel (and hope there is adequate air).

I've run enough engines on dynos (primarily diesels) to know what happens when you try to run at points below peak torque. I'm curious where peak torque would be on the engine in question and if it would even be viable for a direct drive application. My guess is no, and you'd need a reduction box so you could actually get the engine in an rpm range where it would actually produce power. That's aside from the fact that if you wanted to get anywhere near the rated output in the OE configuration you're going to need one.

 

[Ted]

Ahh, the old horsepower vs torque debates...

I'm sure you know this but turning up the boost will effectively do nothing to help matters on its own. Since the diesels are almost always run in a condition where fuel is limiting power you really need to add fuel (and hope there is adequate air).

I've run enough engines on dynos (primarily diesels) to know what happens when you try to run at points below peak torque. I'm curious where peak torque would be on the engine in question and if it would even be viable for a direct drive application. My guess is no, and you'd need a reduction box so you could actually get the engine in an rpm range where it would actually produce power. That's aside from the fact that if you wanted to get anywhere near the rated output in the OE configuration you're going to need one.

Yeah, I was being metaphorical with "turning the boost up." You get the idea.

We agree on the point. I don't see it being viable for direct drive.

 

[lancie00]

Which engine?

The broken one.

Honestly I have no idea which engine it has and I'm not saying combine engines compare to aircraft engines. All I'm saying is that diesel engines can fail with very little warning just like gas engines. And when they do, it's probably going to cost more to fix them than a gas.

Yes, I understand their appeal, especially where there is no 100LL, but I'm not convinced it's the perfect solution.

 

[Kenny Phillips]

Ahh, the old horsepower vs torque debates...

I'm sure you know this but turning up the boost will effectively do nothing to help matters on its own. Since the diesels are almost always run in a condition where fuel is limiting power you really need to add fuel (and hope there is adequate air).

I've run enough engines on dynos (primarily diesels) to know what happens when you try to run at points below peak torque. I'm curious where peak torque would be on the engine in question and if it would even be viable for a direct drive application. My guess is no, and you'd need a reduction box so you could actually get the engine in an rpm range where it would actually produce power. That's aside from the fact that if you wanted to get anywhere near the rated output in the OE configuration you're going to need one.

There is no "horsepower vs. torque" debate. One is a component of the other. And gearboxes can be quite reliable, if properly designed (unlike some experimental PSRUs that hammered themselves to bits due to unchecked torsional vibration.)
The small auto diesel mentioned is within the real of direct-drive speeds, with reduced propeller diameter. A good thing for an experimenter to try.

 

[Grum.Man]

Torque is pretty much irrelevant in an aircraft, it's horsepower that matters since that determines how fast you'll go (with a few other factors, of course). I did a quick search on Google and it said the Cruze Diesel makes 137 HP @ 3750 RPM, which is more or less in line with the early Thielert 1.7s (no surprise given the very similar configuration). So you're still looking at needing a gearbox of some sort and being a power reduction in a 172 vs the existing Lycoming, which were two of the challenges that have always existed. Sure you could turn the boost up, but you're still going to have a hard time making the necessary horsepower at direct drive RPM. The gearbox gets complicated because your torsional vibrations get pretty high. That was why Thielert went with the clutch, which had to get replaced regularly. Diamond seems to have figured it out better.

Plus you have to figure out the dual channel FADEC and get fuel system components that are designed to handle the (lack of) lubricity of Jet A vs. diesel, design your wiring harness and pass all DO-160 tests, etc. etc. etc. Not exactly a bolt-in proposition.

So, ultimately, I'm not seeing anything that's changed yet to make the equation noticeably different than a decade ago.

I wasn't really thinking it would be useful in a 172 but would be perfect for something like an RV9 or similar type airplane. The 1.6TD is making about 120 hp at 2500 rpm and 235 lb-ft of tq. It could swing a big propeller without a gear box. Of course the issue then is the loads imposed on a crank shaft that was not designed to hold them.

 

[tspear]

Ahh, the old horsepower vs torque debates...

I'm sure you know this but turning up the boost will effectively do nothing to help matters on its own. Since the diesels are almost always run in a condition where fuel is limiting power you really need to add fuel (and hope there is adequate air).

I've run enough engines on dynos (primarily diesels) to know what happens when you try to run at points below peak torque. I'm curious where peak torque would be on the engine in question and if it would even be viable for a direct drive application. My guess is no, and you'd need a reduction box so you could actually get the engine in an rpm range where it would actually produce power. That's aside from the fact that if you wanted to get anywhere near the rated output in the OE configuration you're going to need one.

Actually SMA has been making and selling a direct drive diesel for over a decade. They have STCs for a few Cessna planes.
I flew in a diesel 182. It was surprisingly smooth and quite compared to the brand new 182 I demoed earlier in the day.

I have no info on the longevity or costs though....

Sent from my SM-J737T using Tapatalk

 

[mondtster]

The broken one.

Honestly I have no idea which engine it has and I'm not saying combine engines compare to aircraft engines.

My inquiry had nothing to do with aircraft use. Let’s just say I am VERY familiar with Deere engines. At least their newer ones.

From what I’ve seen running them thousands of hours I think they’re pretty good, for the most part. But everything has its faults and everything has a chance to break. And as you’re seeing, (relatively) modern diesels get expensive to fix. Sounds to me like you’ll at least need a liner, piston, head, and injector to get it back up and running.

There is no "horsepower vs. torque" debate. One is a component of the other. And gearboxes can be quite reliable, if properly designed (unlike some experimental PSRUs that hammered themselves to bits due to unchecked torsional vibration.)
The small auto diesel mentioned is within the real of direct-drive speeds, with reduced propeller diameter. A good thing for an experimenter to try.

Actually SMA has been making and selling a direct drive diesel for over a decade. They have STCs for a few Cessna planes.
I flew in a diesel 182. It was surprisingly smooth and quite compared to the brand new 182 I demoed earlier in the day.

I have no info on the longevity or costs though....

You two need to understand the context of my comment. Go look at the statement Ted was responding to, when I responded to Ted. There was a specific engine being discussed.

 

[mondtster]

I wasn't really thinking it would be useful in a 172 but would be perfect for something like an RV9 or similar type airplane. The 1.6TD is making about 120 hp at 2500 rpm and 235 lb-ft of tq. It could swing a big propeller without a gear box. Of course the issue then is the loads imposed on a crank shaft that was not designed to hold them.

As I alluded to previously, where is peak torque?

 

[Grum.Man]

As I alluded to previously, where is peak torque?

1800 rpm

 

[mondtster]

1800 rpm

That *might* work for direct drive but I’d be cautious. If you try to dip below peak torque it ain’t gonna be good. If you can be somewhere between peak torque and peak power in normal operation it should be ok but your horsepower will obviously be limited if you can’t make it to peak power.

So how much power will it make at 2800-3000rpm? How much does the total package weigh compared to a normal aircraft engine? If it can’t beat the aircraft engine it’s a lost cause in my opinion.

 

[Ted]

That *might* work for direct drive but I’d be cautious. If you try to dip below peak torque it ain’t gonna be good. If you can be somewhere between peak torque and peak power in normal operation it should be ok but your horsepower will obviously be limited if you can’t make it to peak power.

So how much power will it make at 2800-3000rpm? How much does the total package weigh compared to a normal aircraft engine? If it can’t beat the aircraft engine it’s a lost cause in my opinion.

When you look at the Thielerts, they were >3,000 RPM and they weighed more than the Lycoming 360s they replaced. And, well, we've seen the results.

 

[Grum.Man]

That *might* work for direct drive but I’d be cautious. If you try to dip below peak torque it ain’t gonna be good. If you can be somewhere between peak torque and peak power in normal operation it should be ok but your horsepower will obviously be limited if you can’t make it to peak power.

So how much power will it make at 2800-3000rpm? How much does the total package weigh compared to a normal aircraft engine? If it can’t beat the aircraft engine it’s a lost cause in my opinion.

I don't know all the answers, simply said being an aluminum diesel it would be a potential candidate. At 3000 rpm it's making about 130 hp.

 

[mondtster]

I don't know all the answers, simply said being an aluminum diesel it would be a potential candidate. At 3000 rpm it's making about 130 hp.

So 130hp, how much weight?

What common airplanes operate with roughly 125hp? Certainly not a 172 or Cherokee but the DA-20 is in that range as are the Sparrowhawk 152s and a few other things.

As a comparison, the Jabiru 3300 makes 120hp and is around 180lbs dry. So maybe 200lbs for the firewall forward?

The Continental IO-240 is a little heavier at around 260lbs.

Those engines and the airplanes they power would be your target. I wonder how it would compare?

 

[Zeldman]

Totally.. 2 stroke diesel is where it's at. Really, 2 stroke in general

Been done before with a little success in airplanes.

https://en.wikipedia.org/wiki/Junkers_Jumo_205

 

[Grum.Man]

I can't find the reference but I read somewhere at some point the 2.0T is about 309 lbs and has the same construction and materials as the diesel so I would assume they are about the same.

 

[Tantalum]

Been done before with a little success in airplanes.

Cool! Over 900 produced, wow

tJus read the full Wikipedia page, what stood out to me was that even though the crankshafts were geared together somehow most of the power, allegedly 3/4 of it, came from the upper bank and pistons

 

[tspear]

My inquiry had nothing to do with aircraft use. Let’s just say I am VERY familiar with Deere engines. At least their newer ones.

From what I’ve seen running them thousands of hours I think they’re pretty good, for the most part. But everything has its faults and everything has a chance to break. And as you’re seeing, (relatively) modern diesels get expensive to fix. Sounds to me like you’ll at least need a liner, piston, head, and injector to get it back up and running.

You two need to understand the context of my comment. Go look at the statement Ted was responding to, when I responded to Ted. There was a specific engine being discussed.

Ah, I took your comment as no direct drive would work, I was giving the counter example.

Tim

 

[Zeldman]

Cool! Over 900 produced, wow

tJus read the full Wikipedia page, what stood out to me was that even though the crankshafts were geared together somehow most of the power, allegedly 3/4 of it, came from the upper bank and pistons

It is an interesting motor. I thought having 6 cylinders and 12 pistons and how they work together was very interesting