Ac-Aero Higgs multifuel engine

[Kyle Communications]

This is a interesting development. Maybe later this year we will see how they are when released

 

 

http://www.ac-aero.com/swift-fl150/

http://www.ac-aero.com/wp-content/uploads/2020/05/ac_FALCON_2020_R00_051820.pdf

[Thruster88]

They appear to be like a GM diesel 2-stroke ie super charged but without the exhaust valves in head.

Not sure how that works.

[kasper]

At US$32,000 fob California it ain’t a replacement for a 912

[Kyle Communications]

Price I saw was US$25,000 AU$39,000 inc GST The 915IS here is AU$60,000

[onetrack]

Andrew Higgs is pretty coy on the fundamentals of the engine design - but essentially, he is taking the designs of Bernard Hooper (deceased, 1997) and his son, Peter Hooper, to further levels.

 

Bernard Hooper was an outstanding motorcycle and automotive engineer, who never received the recognition or adulation he really deserved. His son, Peter, continues his work with Bernard Hooper Engineering Ltd.

 

https://www.independent.co.uk/news/obituaries/obituary-bernard-hooper-1233656.html

 

http://www.bernardhooperengineering.co.uk/bhe.htm

 

There is a link below to a 2005 engineering paper by Peter Hooper, which describes the design of the stepped-piston SPV580 UAV engine, which is based on Bernard Hoopers original ideas.

The SPV580 was a U.K. Ministry of Defence project to find out whether the stepped-piston design was suitable for UAV use. I gather the project was shelved - why, I do not know. This is typical of Defence projects, though, as we all know.

 

I suspect that noise levels were possibly the reason the SPV580 design did not meet the U.K. MOD parameters. As you could imagine, a noisy UAV is highly undesirable.

Being a cross between a two-stroke and a four-stroke, the engine does have noise issues. Not the least of which is, it is a high-speed engine (5000-6000RPM).

 

The basic engine design and principles are sound - but trying to reach commercial success is another level entirely - particularly in the low-volume aircraft engine market, which is now dominated by Rotax.

 

https://openrepository.aut.ac.nz/bitstream/handle/10292/6846/P%20IMechE%20Propulsion%20Systems%20for%20UAVs%28300NA%29.pdf?sequence=2

[facthunter]

Stepped piston two strokes were used nearly 100 years ago in Dunelts and maybe others. Emmissions, exhaust noise and internal (piston) cooling are bugbears of this style of motor. it's not far removed in principle from the GM diesel 2 strokes. Nev

[onetrack]

Nev, the Higgs and SPV580 engine designs are quite a step away from early stepped piston designs, and GM 2 stroke diesels. The big thing with the former engine designs is the total separation of the combustion and oiling areas.

[facthunter]

That's always been available if you wanted it and the GM had it.. It gives you a better chance of cooling the pistons but they still get heated twice as often. I've got a six cylinder( 2 by 3) radial design with a blower, done on much the same principle but I can't see how you would beat the emissions requirements. Nev

[onetrack]

This page explains the principles behind the Hooper stepped piston engine ...

 

http://www.bernardhooperengineering.co.uk/opads.htm

[kasper]

Price I saw was US$25,000 AU$39,000 inc GST The 915IS here is AU$60,000

Don’t know where the price you saw came from. My price comes from the webpage you linked in your post.

My guess is that landed oz incl gst will be near au$55k normal aspiration plus au$10k extra if you want it fuel injected. ... for a start up new design that’s quite steep.

[facthunter]

Thanks for that but (respectfully) there's nothing NEW there and a lot of the valving is pretty generic..(No details) and there's NO easy way of doing it. The motor will be a lot taller than a conventional two stroke also and still hard to cool a piston like that. Best of modern two stroke design will perform better I can just about guarantee. FAR better porting and gas flow.. Nev

[Old Koreelah]

That's a blast from the past! I recall getting excited about each new innovative engine being developed in the Norton works; the Cosworth twin, the Rotary and the Favell/Wulf stepped piston. Each one carried the hopes of a resurgence in the British motorcycle industry. Their engineers and designers were top notch, but how could their production systems compete against hyper efficient Japanese mass production?

[Kyle Communications]

Look at the bottom..dont know where you got the US$35,000 from

 

[kasper]

My mistake. 25+7=32 plus crate and ship at least 3 takes it to 35. Add gst and you’re at 38.5 and then convert to oz peso and it’s au$55 for an injected engine in oz. that is still untested.

 

how much is a six pot Jabiru engine? Same power. Around the same weight ...

Edited July 11, 2020 by kasper

[Kyle Communications]

Only if you want or need the ignition kit..otherwise you run the engine as supplied...most likely on diesel or JetA

[Thruster88]

Only if you want or need the ignition kit..otherwise you run the engine as supplied...most likely on diesel or JetA

The compression ratio is not high enough to run without ignition.

I must confess my ignorance of stepped piston engines before today, now I am wondering why that is.

[facthunter]

Because they weren't widely adopted, although some were produced over quite a few years. The biggest advance was in schneurle porting which made the Loop scavenge system obsolete overnight. Originally adopted by DKW but developed by MZ I think who were the first to get 25 HP out of a 125 cc motor. The US made DOOLING glow plug model race engines used them and ran to 42 000 rpm. A brilliant piece of work. Later reed valved intakes pushed the power higher. Crankcase compression plays a lesser part than gas flow and you are NOT going to get good port shape with stepped pistons. The English maker of SCOTT motorcycles made a timed transfer port 2 stroke engined bike about 1913 that did exceptionally well. at Brooklands. They had a connection with JOWETT and a steam background which is obvious when you examine the engines details. Nev

[Discus647]

That's a blast from the past! I recall getting excited about each new innovative engine being developed in the Norton works; the Cosworth twin, the Rotary and the Favell/Wulf stepped piston. Each one carried the hopes of a resurgence in the British motorcycle industry. Their engineers and designers were top notch, but how could their production systems compete against hyper efficient Japanese mass production?

I worked at the Norton factory at wolverhampton in the 70s and remember seeing the 500 wulf and the early rotary engine as you said lots of promise then the place was closed, i ended up working for Norton on the JPS norton race team from 89 to 93 with great success winning british championships and the iom TT against the japanese teams

[facthunter]

There's Norton Rotary (wankels) in Aircraft. No reason why they wouldn't be satisfactory. Wankels are also in racing outboards Nev

[Old Koreelah]

I worked at the Norton factory at wolverhampton in the 70s and remember seeing the 500 wulf and the early rotary engine as you said lots of promise then the place was closed,[ATTACH alt=NRS 4 Terry.jpg]54614[/ATTACH] i ended up working for Norton on the JPS norton race team from 89 to 93 with great success winning british championships and the iom TT against the japanese teams

Great to hear; I bet you have plenty of interesting stories to tell.

Besides their innovative engine designs, Norton produced so many pioneering innovations in frames, brakes and wheels. They sure deserved to succeed.

[facthunter]

They got "somewhere" despite Joe Craig not because of him.. HE held the company back for years. Have a look at Moto Guzzis Gambalunga of around 1930. Norton had rigid frames till about1938 and a plunger frame that broke next and kept single cylinder motors forever with NO multi valve heads. Look up the AJS V4 and Porcupine and the Gilera's that made the Norton look silly. Sorry to disagree with the MYTH OK.The fastest Norton ever, had an AJS,AMC NVT vertical twin motor in it that wasn't really special either, but it went.. The British Motor cycle Industry died a painful death due to stubbornness and "OUR stuffs is still better and our customers better like them or else" attitude. It was a pity as there is some good crafting and quality especially in some of the frames and engine castings and I don't see the Featherbed as anything spectacular except it was the best THEY produced in numbers at the time especially against the "Garden Gate frame" as it was known that they made previously which was sort of OK till the late 30's.. The brakes were ordinary and distorted drums often with the alloy ones. till they got discs. It's a big and sad story , but when BSA absorbed a lot of others there was no one on the BSA board who actually RODE a motorcycle and there wasn't much research or innovation went on.. Making the same sort of stuff wasn't going to cut it except for a few staunch diehards, for the long haul. Nev

[Old Koreelah]

Nev all that may be true, but my posts (#12 & 20) made it pretty clear I was referring to the last years of the industry, when Norton came up with many innovations.

[facthunter]

They did a lot of promoting their supposed innovations to get people to make advanced payments, invest in etc on promises of great returns. Just didn't happen in reality.. Norton was trading on it's name and image Money wasted on Promo's and high socialising..Nev

[onetrack]

The Japanese wiped the floor with the British, as regards motorcycles in the 1970's. The Japanese bikes offered superior ride and handling qualities, far better fit and finish, attention to detail, more power and smoother power.

In that period, the British companies floundered with vicious, divisive union thugs, management "class divisions" from the 19th century, nationalisation of businesses, left-wing politicians who sold the country down the drain, and a lack of entrepreneurial talent amongst the business leaders of the day. Many good business people fled Britain in that era, to other countries that they felt were more business-minded.

[facthunter]

The Japanese bike was different at the outset. IT had electric start, more cylinders, didn't leak oil and was cheap. You got complexity , performance and technology cheap. I do question the "handling" of the earlier ones. Like their cars at the time, the damping and spring rates were all over the place and the chrome and paint were nearly as bad as the Italian stuff.. You got about 27 different models from each maker and not a lot of interchangeability of Parts across models. Parts supply was often below acceptable. Many makers had to be forced by Law to carry more stock. IF you were a dealer you were REQUIRED to have in the showroom what the Company wanted, not what YOU wanted. You could get stuck with DUD models . The mini bike was promoted strongly for Brand loyalty reasons. Like the Church, Get them in young . The REST is as they say, HISTORY. Nev