Experimental with a diesel engine

[facthunter]

The higher the peak temp also affects the efficiency. This applies to turbines also. Look up CARNOT cycle.  Nev

[facthunter]

Diesels run very heavy flywheels also and One Nissan model ran two vibration dampers. I reckon they'd demolish a conventional propeller. Friction also is RPM squared. Large Radials and some flat sixes have active vibration dampers as part of the crankshaft bob weights and they have "NO GO" RPM ranges,  Nev

[red750]

I took this photo at Avalon Air Show 2015. The website on the plane no longer exists.

 

[facthunter]

D-Motor, a flat four sidevalve. It was  discussed HERE. "D" does not mean Diesel .Nev

Edited September 20, 2022 by facthunter
more content.

[CT9000]

The main problem with a sidevalve engine is that most of the combustion energy is expended trying to blow the head off the block rather than push the piston down the bore.

[facthunter]

If nothing moves no work is done. W= FxS,(distance) but the heat loss over the large area counts. Once the piston moves the adiabatic expansion makes the temp and pressure rapidly diminish. Supercharged engines push (the piston) for longer. Nev

[spacesailor]

ct9000

The ' old ' Commer knocker.

Had No cylinder heads, !

Just three barrels.with six pistons .

I thought it sounded great !. LoL

spacesailor

[facthunter]

Noisy mainly because it's a 2 stroke. Hard to start cold also.   Nev

[onetrack]

The Roots blower on the Commer Knocker produced the largest level of most annoying noise. In 1995, I had the doubtful pleasure of driving an ancient Commer Knocker from Geelong to Norseman. It's not a trip I would wish to repeat.

[Ian]

So from the above

• Diesel enjoys about a 10% advantage volumetric advantage over petrol and as you buy it by the litre that's pretty important. 
• Diesel also enjoys a more efficient combustion process which adds another 20% or so advantage in terms of the efficiency extraction process. 

 

On a weight for weight basis you lose the 10% advantage however you still see the 20% combustion efficiency advantage of the diesel.

Basically this is a thermodynamic limitation brought about by the much lower temperatures associated with petrol combustion due to lower compression.  PV=nRT

 

 

[facthunter]

Your plane is usually weight limited as regards performance so fuel density is used to determine that in your pre take off calcs.    Nev

[Ian]

On 20/09/2022 at 2:56 PM, red750 said:

I took this photo at Avalon Air Show 2015. The website on the plane no longer exists.

https://en.wikipedia.org/wiki/D-Motor

I thought that it was a diesel but instead it was a flathead side valved engine. Can't say I'm a fan, but I like the sleeve valved engines https://en.wikipedia.org/wiki/Sleeve_valve

 

I also like the Deltic engine which is a design which could push some good power to weight figures. https://en.wikipedia.org/wiki/Napier_Deltic

 

Edited September 21, 2022 by Ian

[Thruster88]

🤔

https://www.facebook.com/100063068507532/posts/pfbid0siQ89AFqjxQmVdEuM9Njs5EpYZeH9khZ6Fs4hcWaCsHkVBAUxqrvoU13GQqYpnGUl/

[turboplanner]

11 minutes ago, Thruster88 said:

🤔

https://www.facebook.com/100063068507532/posts/pfbid0siQ89AFqjxQmVdEuM9Njs5EpYZeH9khZ6Fs4hcWaCsHkVBAUxqrvoU13GQqYpnGUl/

Hmmmmmm 

I think I posted how you can't turn the engine off in a current Honda, take the battery out, then put a new one in becaise it's all too late - roughly similar reasons.

[onetrack]

Quote

I think I posted how you can't turn the engine off in a current Honda, take the battery out, then put a new one in becaise it's all too late - roughly similar reasons.

I don't recall this previous posting. What is the problem with Honda electrics, when you carry out a battery swap?

[turboplanner]

1 minute ago, onetrack said:

I don't recall this previous posting. What is the problem with Honda electrics, when you carry out a battery swap?

You'll have to search back for the exact procedure because I'm suffering brain fade at present, but after two or three battery outlets refused to install a new bettery for me I found that a special procedure was required which ensured that 12v power was not lost during the changeover and Supercheap and Autobarn didn't have the electronic equipment (or weren't prepared to completely reboot and reprogramme the electronic unit from ground zero. Being resourceful I bought a battery from an on site RACV van and casually asked the technician to fit it, making notes of the sequence.

[turboplanner]

I'll have the notes filed somewhere, will post them when I find them.

 

[onetrack]

Is this an older Honda? Some of the earlier vehicle models had this problem, but 99% of vehicles today don't have the problem because they have a backup battery built into the ECU.

 

The Diamond DA62 crash appears to be more related to incorrect wiring for the FADEC unit. The Farcebook post doesn't say if this was from the factory, or if it was due to recent maintenance.

I don't see how the Honda problem (lack of an ECU backup battery) relates to the DA62 problems.

[turboplanner]

2 minutes ago, onetrack said:

Is this an older Honda? Some of the earlier vehicle models had this problem, but 99% of vehicles today don't have the problem because they have a backup battery built into the ECU.

 

The Diamond DA62 crash appears to be more related to incorrect wiring for the FADEC unit. The Farcebook post doesn't say if this was from the factory, or if it was due to recent maintenance.

I don't see how the Honda problem (lack of an ECU backup battery) relates to the DA62 problems.

Scratch that post - specifically related to the latest models and a deprival of power.

[onetrack]

O.K. So, the DA62 problem was someone installed the ECU batteries back to front. I guess it's a bit harder today, to find a LAME who recognises what + and - mean. Then again, more than one experienced individual has connected battery jumper leads back to front.

 

The difference is the battery jumper leads will let you know your connective error in an unmistakeable fashion! Not so, ECU backup batteries.

 

Here's a good warning about road outlandings, that I've mentioned before. Those road signs will get you every time!

 

http://www.kathrynsreport.com/2022/10/diamond-da62-n84lt-incident-occurred.html

 

 

 

Edited November 4, 2022 by onetrack

[Thruster88]

40 minutes ago, onetrack said:

O.K. So, the DA62 problem was someone installed the ECU batteries back to front. I guess it's a bit harder today, to find a LAME who recognises what + and - mean. Then again, more than one experienced individual has connected battery jumper leads back to front.

 

The difference is the battery jumper leads will let you know your connective error in an unmistakeable fashion! Not so, ECU backup batteries.

 

Here's a good warning about road outlandings, that I've mentioned before. Those road signs will get you every time!

 

http://www.kathrynsreport.com/2022/10/diamond-da62-n84lt-incident-occurred.html

 

 

 

Pilots are able to replace batteries, not saying that is what happened here. If the backup batteries were connected with reverse polarity it would surely appear as a warning on the EFIS in the same way as low voltage on the main or backup battery, alternator or backup alternator not charging etc.

[onetrack]

The Austro engines in the DA62 are fitted with a FADEC specifically designed by Bosch for the Austro engine. The ECU backup battery for the Austro FADEC appears to be wired in, there's nothing to indicate it's a simple "push fit into a compartment" arrangement.

 

There's nothing mentioned about a system check light or warning for incorrect ECU backup battery wiring polarity - something that Diamond and Austro probably thought was unnecessary - because battery installers are supposed to be alert to correct battery polarity.

 

Incidentally, the Thielert diesel engines came with no backup battery for their FADEC, and there was a similar forced landing around 2010, caused by a Thielert FADEC failure, in turn caused by low battery voltage.

An AD was issued by Piper for its Theilert-engined aircraft, whereby a backup battery for the FADEC was required to be installed. This AD affected no aircraft in the U.S.

 

https://www.aviationconsumer.com/industry-news/diamonds-austro-diesel-performance-in-search-of-durability/

 

https://www.piperflyer.org/knowledge-base/aviation-alerts/item/87-2009-ce-057-ad-fadec-backup-battery.html

 

HISTORY: - Both the Thielert and the Austro engines are based on Mercedes car diesels, substantially reworked for aviation use. Thielert went to the trouble of casting an entire new engine block from aluminium for their aviation engines, but Austro (owned by Diamond) utilises the standard Mercedes cast-iron block.

The Austro engines are considerably heavier than the Thielert engines, but Diamond simply recertified the aircraft for an increased MTOW to accommodate the extra engine weight.

[turboplanner]

7 hours ago, turboplanner said:

I'll have the notes filed somewhere, will post them when I find them.

 

Haven't filed it - typical after the emergency was fixed, didn't matter, but it will again next time so I'll check through paperwork.