A very nice 2.5cc control line speed engine

[Former MemberParticipant @formermember32069]

[Former MemberParticipant @formermember32069]

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[SteviegtrParticipant @steviegtr]

Are you sure of the power output. 1 bhp per cc.

Steve.

[Former MemberParticipant @formermember32069]

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[Neil LickfoldParticipant @neillickfold44316]

Awesome Barrie. The work that has gone into that engine is nothing short of incredible. Quite a team effort from design concept to the manufacturing. I have seen the amazing gear Rob has and the skills he has to us it as well. The edm of the ports really is something, and will be a big part of the consistency and the performance gains that does not happen with every casting. The precision that is on one of these is hard to explain to people and to why it is needed. I like the way they can calculate quite accurately the thermal changes in a running engine and then the dimensional changes that are occurring. Some parts 5 micron doe snot really matter, other parts a 5 micron error makes it become an also ran engine.

Thanks for the posting and pictures etc.

Great to see.

Neil

[HopperParticipant @hopper]

That thing looks like 100mph just sitting there on the bench. Beautiful.

[Ady1Participant @ady1]

1 BHP = 750 watts

lol

[Former MemberParticipant @formermember32069]

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[JasonBModerator @jasonb]

What's the speed they are aiming for Barrie? Similar to tether cars or higher.

I won't ask the price or service interval of that engine but a very nice job on the crankcase both in being able to draw it and the final machining. Any idea of the run time to sculpt the outside?

[Old SchoolParticipant @oldschool]

The speed should be in excess of 300kph in an controline aircraft, the current tether car record is 285kph held by a Norwegian his car and engine are home built his engine revs to 42 to 43,000. Both types of engine run on straight fuel 80% methanol and 20% castor oil.

Barrie that’s an interesting engine project like the spark erosion for doing the transfer ports certainly better than the cast crankcases on my 2.5cc tether car engines. What piston liner set up have the gone for ABC or AAC ?Look forward to seeing some results.

[Danny M2ZParticipant @dannym2z]

Thanks for the info Barrie.

So, ceramic bearings or steel balls?

ABC or ceramic coated liner?

Enquiring minds need to know

* Danny M * (aeromodelling tragic)

[IRTParticipant @irt]

Do people still fly control line in these days of cheap radio?

[Former MemberParticipant @formermember32069]

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[Former MemberParticipant @formermember32069]

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[Former MemberParticipant @formermember32069]

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[Niels AbildgaardParticipant @nielsabildgaard33719]

Posted by Steviegtr on 12/06/2020 22:56:30:

Are you sure of the power output. 1 bhp per cc.

Steve.

One of the ultimate limits to power from combustion engines is that air/fuel cannot pass a hole/port/valve faster than sound speed.

The relation of maximum port area to cylinder volume is helped by being a small cylinder.

Let us say a worldbeating 2.5ccm engine has a port area of max 50 square and can pass air /fuel that gives 2.5 horsepower.

If we enlarge all linear dimensions by 1.38, we get 6.5 cubic cm and get 95 square mm port in very good accordance with the mentioned power of 5hp for a 6.5 cubic engine.

It is the cube/square law at work.

Edited By Niels Abildgaard on 13/06/2020 10:22:52

Edited By Niels Abildgaard on 13/06/2020 10:23:48

[Martin Dilly 2Participant @martindilly2]

Posted by IRT on 13/06/2020 09:32:49:

Do people still fly control line in these days of cheap radio?

The reason people fly control-line and free-flight isn't because RC equipment is too expensive for them; it's because they enjoy a different challenge in a different type of man-and-machine sport and doing so while competing with other people adds to the enjoyment. The fact that control-line speed and free-flight duration competitions are purely objective, with a stopwatch to decide the result instead of some judge's opinion, adds to the appeal for many of us. No 'halo factors' involved!

Wow! What an engine; I look forward to seeing some figures when it gets let loose in an F2A model.

[Former MemberParticipant @formermember32069]

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[BC ProfParticipant @bcprof]

I have flown a variety of control – line and free flight models for over 60yrs. Initially because it was all I could afford and latterly simply because it is still fun. I am not interested in "buy it and fly it" although I did have fun with a Keil Kraft RC Outlaw with a 2.5ccc diesel engine ( The "experts" opinion was that you could not fly radio with a diesel) I still enjoy converting big bits of balsa wood to smaller pieces , then back to bigger pieces and usually back to small pieces. Making single bladed carbon fibre props for F2A was fun but then so was making catapult launched Deltas with no danger from the resins. .Like most of us a hobby provides challenges and fun. at whatever level.

[Martin Dilly 2Participant @martindilly2]

Barrie,

Is that really a bar stock crankcase? It looks like a very nice bit of pressure die castng to me, but what do I know? Next year's Euro CL Championships should be interesting with one or two of those in the mix anyway.

Martin (omnipresent but not omniscient).

[BC ProfParticipant @bcprof]

The design and engineering of the F2A engines just has to be seen to be believed . The cost and short life time at peak performance was staggering in the 1990's . Things have moved on since then . Has anyone heard anything of Ian Mander of f2A supplies? I lost contact with him when he sold the model shop in Wellington NZ.

[old martParticipant @oldmart]

Just the thought of it makes me giddy. Many years ago, I had a little control line plane powered by 0.76cc Quickstart diesel engine. The fuel tank was on the back of the engine, but I thought I was being clever to ditch that and fit a metal tank of about five times the capacity. Big mistake, by the time it had run out of fuel, I was feeling quite ill.

[Former MemberParticipant @formermember32069]

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[Neil LickfoldParticipant @neillickfold44316]

Most F2A engines use a Bronze or BeCu for the liners, with 30% Si piston material. Some still use steel balls while most now use ceramic balls in the bearings.

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