alternatives to the 'best VW conversion'.

ColinC · Post by **ColinC** » Sun Oct 19, 2008 8:25 pm

the post on VWs was very interesting, and clearly the VW is the most popular 'non-aircraft' engine, but what other conversions are available? Looking at the engine/prop list I can see a few converted Subaru EA81 engines but is that it?

I get he impression that in the UK we are a bit more conservative than other countries about what we allow in aircraft. What are the criteria? Is it to do with redundant ignition systems?

Colin

Steve Brown · Post by **Steve Brown** » Sun Oct 19, 2008 9:04 pm

I would guess the standard reply would be CS-E which is the lesser known (link not even on LAA website ) engine version of CS-VLA (which is) which is LAA bible for new designs, modifications to existing etc. I understand LAA engineering have some latitude in how rigidly they apply it and to what aircraft combo (low stall speed single seaters seem favoured for this) but CS-E is the starting point I think and that indeed does require redundant ignitions (unless equivalent reliability can be demonstrated)

ie CS-E para 240 says

CS-E 240 Ignition
All spark-ignition Engines shall comply with the following:
(a) The Engine shall be equipped either with:
(1) A dual ignition system having entirely independent magnetic and electrical circuits, including
spark plugs, or,
(2) An ignition system which will function with at least equivalent reliability.
(b) If the design of the ignition system includes redundancy :
(1) The maximum power reduction resulting from loss of redundancy shall be declared in the
appropriate manual(s).
(2) Provision shall be made to establish the serviceability of the ignition system. The associated
procedures and required inspection intervals shall be specified in the appropriate manual(s).
Annex to ED Decision 2007/015/R
Amendment

Whole document found here :
http://www.easa.eu.int/ws_prod/g/rg_certspecs.php#CS-E

choose CS-E/Amendment 1 pdf

Regards
Steve

Nick Allen · Post by **Nick Allen** » Sun Oct 19, 2008 9:44 pm

...does require redundant ignitions (unless equivalent reliability can be demonstrated)

How does one demonstrate that?
(And I note in passing that the certified aircraft I fly has a single mag and one spark plug per cylinder...!)

Frank Parker · Post by **Frank Parker** » Mon Oct 20, 2008 12:40 am

Nick, I imagine that a lot of us are wondering what your single ignition aircraft is. Motor glider perhaps?

ColinC · Post by **ColinC** » Mon Oct 20, 2008 8:14 am

Does anyone know what happens in the Subaru conversions, do they have dual plugs?

Colin

Nick Allen · Post by **Nick Allen** » Mon Oct 20, 2008 9:21 am

Parkair, You're right -- it is indeed a motorglider. Does this mean these are exempt from the CS-E requirements that Steve described?

MikeGodsell · Post by **MikeGodsell** » Mon Oct 20, 2008 8:12 pm

Welshman no redundancy problem since no spark ignition system. However that assumes the diesel engine uses a mechanical injection system. Thielert muddied the waters when they very sensibly chose an all alloy car engine, but then retained common rail diesel injection. Common rail is inherently unsuitable for aircraft, since a simple electrical failure will mean loss of the engine. Thielert designated electrical problems a major emergency requiring the aircraft to land within 30 mins. Attempts to provide backup or dual electrical supplies began to increase weight and complexity to ludicrous levels.
In contrast the Gemini engine by Jade Air / Power Plant Developments is really practical and quite exciting. It is similar to the German Junkers opposed piston engine used in WWII. The 100 hp version weighs less than my Limbach and will fit comfortably inside the existing cowling. Reliability is going to be one of the many advantages. No valves or valve gear, no carburetter and carb heat, no mixture control, no ignition system, and if you have ever stood in a pool of diesel oil and thrown lighted matches, you wiil know that diesel is much safer than avgas!

ColinC · Post by **ColinC** » Mon Oct 20, 2008 10:43 pm

paulhs wrote:A quick answer for Colin C, I did some work a few years back with a company in Washington that did Subi conversions. They used an electronic ignition system with 2 supplies and 1 plug, it was made by Electromotive, very neat and during my time we never had an issue with the ignition system, other things yes but not the ignition.

Paul

Thanks, I am interested to know what is normal for UK Subaru conversions, are they dual plugs? I believe that I read somewhere of that but can't recall where.

Colin

mike newall · Post by **mike newall** » Mon Oct 20, 2008 11:12 pm

Mike,

If Jade are (were) involved, we may have a wait.................

MikeGodsell · Post by **MikeGodsell** » Tue Oct 21, 2008 9:19 am

Mike N
Tim Archer of Powerplant Developments has e-mailed me to say they are currently I year behind on their production schedule for the Gemini 100, and a bit more for the 125 hp version. This seems to be due supplier problems in UK, and the present financial crisis. However they are getting attractive offers from US based investors. Right now they are using the delays to accelerate bench & flight testing at their Hastings base in UK. This is probably one of the best diesel designs around, and I sure hope it does'nt go across the pond like so many other British ventures.

MikeGodsell · Post by **MikeGodsell** » Tue Oct 21, 2008 10:22 am

This Belgian site may be of interest to Subaru enthusiasts. Gives a good description of what works and what does not.
www.jsb-engines.be

Mike Fawdrey · Post by **Mike Fawdrey** » Tue Oct 21, 2008 5:24 pm

I dont know if the owner visits this web site but a few weeks ago on the AFORS web site there was a Jodel for sale with a Subaru power unit.
I cant remember the reg now but it seemed a nice machine.
Perhaps it might be worth trolling through G-INFO

Light Aircraft Association

alternatives to the 'best VW conversion'.

alternatives to the 'best VW conversion'.

Subaru engines