Was looking at the Piper website and I saw a Piper Archer DLX with a Continental CD-155 Engine.

It cruises at 123KTAS, with a 16,100ft. Service Ceiling for 848 miles. And holds 48 gals usable. That's 6.5 hours on less than 8 gals an hour JET A.

It's not a fast trip, but is rather economical.

Does anyone know of anymore Pros and Cons of the CD-155 engine?

I would say:

1. FADEC for single lever operation training
2. FADEC for an “automated”, simple start process
3. Opens up a European market for non 100LL needs
4. Possibly a starting point for larger engines for reduction/elimination of 100LL in the US
5. Access to what is typically lower priced Jet-A

To name a few off the top of my head.

Brad

The speed is about on par with the Lycoming version. I wonder how much of a premium the Diesel is commanding. If Diesel could somehow take off here, it would go a long way toward mitigating the leaded fuel issue for new airplanes.

I think I have seen some of the diesel engines specifications state a Cetane Number requirement.

I have wondered about this since Cetane Number is not in the Jet A specification.

I thought the Diesel was just Jet-A?

The diesel version is slower in cruise, climbs more slowly, has less useful load, and costs about $40k more that the avgas Archer. It's really a two place airplane suited for training, because it's a pig when fully loaded. The diesel adds 96 pounds to the empty weight, but has 25 HP less (155 vs 180 hp).

while technically true, cetane is never an issue with jet fuel. Many diesel engine manufacturers have fuel system settings specific to operating on jet fuel, as well as coatings on high pressure fuel components to handle the reduced lubricity of the fuel. Unrestricted operation on jet fuel has been a requirement to sell diesel-powered machines to the military since the 1970's.

As a practical matter, the only thing you really need to adjust for is fuel density. Kerosene is lighter so you need to inject more volume per stroke, meaning either longer injection duration, higher pressure, or bigger nozzles. You also tweak start-of-injection timing if you go the longer duration route. That gets you the same power as with #2 diesel fuel. Presumably these aircraft diesel engines intended to run on jet A, will be tuned from the outset for the lighter fuel. And if it's a warm day and you need a little more grunt, I'm sure someone will put 2&2 together and and put some #2 diesel in the tank instead of jet fuel.

That's surprising and more than a little silly. The Diesel engine should be able to perform as well as the gasoline engine on less HP because it's not about horsepower it's about torque. The Diesel should out torque the gas engine by a lot. Crank in some pitch on the prop and voila. Weighs more, costs more, no surprises there, but the performance and useful load shouldn't have to be a compromise.

That's surprising and more than a little silly. The Diesel engine should be able to perform as well as the gasoline engine on less HP because it's not about horsepower it's about torque. The Diesel should out torque the gas engine by a lot. Crank in some pitch on the prop and voila. Weighs more, costs more, no surprises there, but the performance and useful load shouldn't have to be a compromise.

Hp is Hp when you have a constant speed prop that you can operate at any RPM that provides the most Hp/

be sides being heavier and less HP, the Theilerts have an aluminum block and you throw the engine away at TBR (time before replacement.) also look at the gear box overhauls.

in general the diamond is a much better engine as far as lifetime cost.

a possible future solution is to have a gasoline engine that runs on any available gasoline.

this is an example if they can get the $$ to get it into production that would use any available gasoline,

https://flyadept.co.za/

280 to 360 Hp in a package that will fit in the existing space that is available in a Cherokee etc and will run on any available gasoline.

If things go well they hope to have two flying aircraft at OSH

Bring back the Napier Nomad concept:

Two stroke turbocompound diesel.

Looks great until you see the price. $76k for the bare 280 HP experimental engine. Plus engine mount, plus all new engine to airframe components, and a new propeller.

A brand new Lycoming engine is much less money, and without all the extra expenses. I don't see how this makes any sense. If the $76K were for a complete firewall forward certified package, then we can talk.

If I wanted a 280 HP experimental aircraft engine, I'd buy a Ford 3.5 V-6 for $8k.

Not CD-155 specific, but -

Converting a gas airplane to diesel usually results in a significantly heavier, more expensive engine and you can’t make up the difference with smaller fuel tanks. For a private owner (not a fleet) it doesn’t make sense to own an oddball airplane that needs different parts and knowledge to maintain.

My guess is they want a plane suitable for trainer fleets outside the USA. And perhaps inside the USA if 100LL goes away and the replacement fuel is too expensive.

Taking the Archer down from 4 people to 3 (assuming all are young skinny CFI’s and students) is a pretty reasonable way to solve the problem since training fleets don’t need the last seat or heavy baggage. Cessna could do something similar on the 172.

When Glasair put the diesel in the Sportsman it received the same criticisms off the cuff. These criticisms came from folks who looked at the easy numbers.

Yes, it had less HP at sea level. Yes it was heavier. Yes it was more expensive. OK, so why would one want a diesel Sportsman?

At anything other than seal level ISA the diesel started to walk away from the Lycoming pretty quickly. By the time one hits 8000' the poor Lycoming looks pretty sickly. The diesel starts far easier. Also, there are a bunch of places in the world where gasoline, especially avgas, is unobtanium - these are the places where the diesel really shines.

Would I want to own a diesel Sportsman? You bet I would!