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AC-Aero Jet-A engine

HAL Pilot

Well Known Member
http://www.ac-aero.com/jet-a/

Just had a short correspondence with Andrew at AC-Aero about their deisel compression engine. He said there is one being installed on an RV-10. Whoever is doing that install I would love to hear some pireps about the engine.
 
I've watched the development of these innovative engines for some time. Seems like production is near. Some questions:

Have any test engines gone to 3000 hours during durability and validation testing?

Are compound turbos being used on the turbo models to get to 50,000 feet and have any engines been flight tested there or in an altitude chamber?

When will engines be available to the public?

Introducing 4 new engines and 4 sub models simultaneously is unprecedented for any established aircraft OEM. How many test/ flight hours on each engine, sub type and gearbox?
 
Higgs diesel just posted the price list for their engines:

http://www.ac-aero.com/downloads/

HAWK V4 E-330J/G engine MSRP is $58000 + $18000 for ignition kit? That is $76000 total! Why would anybody buy this engine instead of Lycoming IO-540 for RV-10?

$76,000 and that doesn’t even include a starter motor.....ridiculous!! You can currently buy an IO540 for the RV10 from Vans for $49,200....and that DOES include a starter motor. ;)
 
Pricy engine

Price is one thing. The most important information is just not there.
No flight testing of the engines on an aircraft.
No information on engine torque.
No statements from happy customers on ANY of their products.
The only thing we know for certain is that the aircooled aluminium AX40 cylinder for lycoming engines is out of production. It just did not work.
 
It hit me and would like to hear other’s with prop aero expertise. The max prop RPM listed is 1992. I’m also assuming there’s no hydraulics available for prop pitch control. Might be wrong there but there’s no evidence included on their website to suggest otherwise. How much will a prop cost that is optimized for the power plant conditions?

The electric props I’ve seen (been a while) I’d consider more “pitch adjustable” than constant speed. Maybe they’re better now. Is the power management supposed to be the same technique as existing PPs? Any applicable aero would have to be optimized for the much slower speeds. As mentioned, can any experts weigh in? The deeper I look, there’s more questions than answers.

I did stop by their booth at SnF. I listened to their dialogue which on the surface was impressive. I listened to other’s questions get answered. IMO, more sales speak than technical though to be fair, that was the majority of the questions. I couldn’t resist so I asked for torque values on their two strokes as I couldn’t find anything on their website. The answer was “it’s very good”. Asked for actual numbers and was told they were purposely not published. Said nothing else and soon left. It did not help my skeptical nature but that’s my nature/problem. That should be a surprise to no one.
 

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Good to hear

It's good to hear that the OEM, AC-Aero is monitoring the forum.

Can you get us smarter on your product? Specifically, your literature mentions Combined Cycle Technology often. The Otto is obvious. Which other thermodynamic cycle is being utilized in your engines and how is it being applied? Any details you can provide here would be appreciated. Thanks
 
It's good to hear that the OEM, AC-Aero is monitoring the forum.

Can you get us smarter on your product? Specifically, your literature mentions Combined Cycle Technology often. The Otto is obvious. Which other thermodynamic cycle is being utilized in your engines and how is it being applied? Any details you can provide here would be appreciated. Thanks

AC-Aero isn't an advertiser presently here on VAF so his posts have been removed by a mod. Hopefully Andy will see the advantages of advertising here and be able to answer your questions.

I hope he will answer my questions from post 5 at some point...
 
Well, I've just returned form Oshkosh. AC Aero had HAWK V4 E330J/G-T with RV-10 mount for display. I talked to AC Aero representative and he said they are building RV-10 to install this engine in it. He said the are planning to fly it sometime next spring. I asked him about the propeller, and he said that AC Aero is working with prop manufacturers to come up with a prop that will be a match for this engine/gearbox RPM. So the prop may be three and even four blade.
 

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Just me

Snf price on the io540 was $53k. Thunderbolt, that is.
There are quite a few places in the world where av gas just isn't available. In those places, diesel at any cost. Now one might argue that the market may not be large enough to allow a ramp up in production and economies of scale to kick in.....
 
There are quite a few places in the world where av gas just isn't available. In those places, diesel at any cost. Now one might argue that the market may not be large enough to allow a ramp up in production and economies of scale to kick in.....

In Europe Jet A is about 1/3 the price of a avgas and 1/2 price of mogas. So if the engine was close in price to a Io 540 there would be a decent increase in market for both the engine and RV10’s I would think
 
In Europe Jet A is about 1/3 the price of a avgas and 1/2 price of mogas. So if the engine was close in price to a Io 540 there would be a decent increase in market for both the engine and RV10’s I would think
The engine price is $58000 + ignition kit $18000, total is $76000. This is higher then IO-540. The AC Aero representative at Oshkosh said that better fuel efficiency, less maintenance, les expansive fuel will overall make a savings over Lycoming IO-540. I need to see it to believe it ...


https://www.ac-aero.com/wp-content/uploads/2020/05/ac_hawk_2020_R00_040720.pdf
 
The engine price is $58000 + ignition kit $18000, total is $76000. This is higher then IO-540. The AC Aero representative at Oshkosh said that better fuel efficiency, less maintenance, les expansive fuel will overall make a savings over Lycoming IO-540. I need to see it to believe it ...


https://www.ac-aero.com/wp-content/uploads/2020/05/ac_hawk_2020_R00_040720.pdf

It very well may - but if the barrier to entry is sufficiently high, it doesn't matter what's on the other side.
 
Can I provide my own ignition and save $18K? I can buy quite a few SDS systems for that amount!
This engine is a "combined cycle, 2 stroke", very unique design, using Jet-A fuel (among other fuels listed), spark ignited diesel engine. There is no third party ignition system for this engine, as far as I know.
 
The engine price is $58000 + ignition kit $18000, total is $76000. This is higher then IO-540. The AC Aero representative at Oshkosh said that better fuel efficiency, less maintenance, les expansive fuel will overall make a savings over Lycoming IO-540. I need to see it to believe it ...


https://www.ac-aero.com/wp-content/uploads/2020/05/ac_hawk_2020_R00_040720.pdf

Did the rep give any indications of how many dyno and flight hours to date on the engine or BSFC figures?
 
I ask because this is important when you're laying out $50K+ on a new engine design. AC-Aero has never answered any questions about flight testing or even the ground testing program.

That's something I'd want to know before buying.

Nothing on their website that I can find, which apparently hasn't been updated since 2020.

Does anyone know if any of these engines have flown yet?
 
I ask because this is important when you're laying out $50K+ on a new engine design.
I agree completely. Few weeks ago I ordered an RV-10 empennage kit. In about three years I will be looking for engine. I will follow development of AC Aero, and there is always good old Lycoming 540.
 
Did the rep give any indications of how many dyno and flight hours to date on the engine or BSFC figures?

They are now quoting torque and BSFC now, though you have to search around for both, they aren't necessarily in the same part of the website.
 
They’ve been quoting that for years. Again, would love to see this engine run! But until it does…
 
I heard about AC Aero Hawk V4 being pushed hard at SnF again, but curious if any actually engines have been tested or flown with any results or data to share. Anyone heard anything in this regard?
 
I heard about AC Aero Hawk V4 being pushed hard at SnF again, but curious if any actually engines have been tested or flown with any results or data to share. Anyone heard anything in this regard?

I've been asking these questions of Andrew for several years now. Crickets...

Some transparency and data would go a long way in prompting interest.
 
I talked to the CEO, George recently. He said the Hawk was stalled in production during Covid but they were able to start ramping back up late-2021. The first of them are being delivered in other parts of the world where 100LL isn't available and a few military applications.

He said he was thinking about putting one in his Harmon Rocket and flying it to OSH. I told him that would be one of the smartest things in the world to do. I hope he does.
 
Since you have an "in" here, could you ask George about their ground durability and flight testing program? Must have done some prior to supplying production units.

Curious minds would like to know.
 
I’d love to see some proof of a completed, running engine. I too have been asking for years. Seems that they are taking deposits now. But again, same makeup for three years and no evidence of any engine running. I want to be proved wrong, though as it’s very intriguing. Not an easy process, I’m sure but no communication sure does damage reputations.
 
Since you have an "in" here, could you ask George about their ground durability and flight testing program? Must have done some prior to supplying production units.

Curious minds would like to know.

:) Well, I don't really have an "in." Just his business card I got from him last year at OSH21.

He'll be at OSH22, so I hope everyone drops in to ask questions and express interest. They DO have the RV-10 engine mount complete. No doubt due to the work done at the beginning of this thread.

I'm still 3 - 5 years out from having an airplane ready for an engine, and I'll probably hang an IO-540 on it for the first couple of years since it's a known quantity in my community with straightforward parts and processes. But after awhile, I definitely want to look at upgrading to this engine.
 
The RV-10 engine mount, to my knowledge, is not complete. Andy scanned my stock mount that I sent him and then designed the one they've been showing at OSH and SnF for a few years now. It's never been mounted to a firewall nor has any accessories been attached or designed. Again, I'd like to be proven wrong by Karl or the new build center.
 
The RV-10 engine mount, to my knowledge, is not complete. Andy scanned my stock mount that I sent him and then designed the one they've been showing at OSH and SnF for a few years now. It's never been mounted to a firewall nor has any accessories been attached or designed. Again, I'd like to be proven wrong by Karl or the new build center.

Interesting... well, I'm glad I've got a few years of runway. I've got thousands of rivets to pound first.
 
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