Aero vs auto vs industrial

  • Purpose-built AERO engines:
    These come in two flavours.  Pre-war designs and modern engines.  I wouldn’t drive a car with an engine designed before the war, and neither will I fly a plane equipped with one of these engines.  Those in favour of these dinosaurs go on about how they have stood the test of time, how they are tried and true etc.  But I’m not convinced.  I wouldn’t put one in my car.  Bottom line.  What engines am I talking about here?  Your Lycomings and Continentals.  Besides, they cost a FORTUNE.  (Did you see the upper case letters in “fortune”?).  Like $28k  So, let’s not hear anything more about them.Fortunately, there are some excellent MODERN aero engines on the market today (also big bucks, but not horrendously so).
  • HKS: http://www.hks-power.co.jp/hks_aviation/
    In all my searching of the Internet, I have NEVER come across a single bad word about these engines.  Except, possibly their price (about $12k).  They come in normally aspirated (60hp, 121lbs complete with gearbox and exhaust) and the new turbo version, which costs considerably more, and doesn’t produce that much more power.
  • Rotax:  http://www.rotax-aircraft-engines.com/a_engine_912.htm
    Mmmm despite their much-vaunted reliability, I just don’t LIKE them.  They sound terrible (like little sewing machines whirring away), they are far too fiddly for my liking, and they cost almost as much as the Lycomings/Continentals of this world.  I think there are better engines than the 912 (80hp) and the 914 (100hp turbo).  About four times the cost of some other aero engines, like the VW conversions).
  • Jabiru: http://www.jabiru.net.au/
    This Australian designed and built engine comes in 4 cylinder (85hp, 132lbs) and 6-cylinder (120hp, 178lbs) and is one of the engines of choice for the Sonex.  I’d take the 4-pot Jabiru over the Rotax any day of the week. But they are also not cheap.  (About twice the price of some other nice engines).
  • Verner JCV-360
    If you’re looking for something in the region of 40hp, then you have just GOT to check out the new Verner JCV-360.  It is a purpose-built aero engine, 4-stroke, water cooled boxer.  Weight = 26kg.  Wow!  Talk about a great pedigree.  At 35hp, however, it just doesn’t quite have the oomph I’m personally looking for, but if you can live with 35hp, then this one might be for you.  Cost?  Apparently (I have this 3rd hand, however…  4,100 Euro)Here are some details from their web site:  (http://www.vernermotor.com/old/index474c.html?sec=41)
  • Smaller AUTO conversions (under 80hp)
    If you’re looking at smaller engines, one engine to consider is  the Geo/Suzuki G10

   

  • Raven Redrives are another source for this fine little engine.  They’re based in the US, and are very active on the small engine forum at Yahoo Groups.  Again, not a cheap option.

You can find them here: http://www.raven-rotor.com/

  • Larger auto conversions (80 to 100hp)
    I know I’m going to be shot down in flames for this, but although there are literally scores of companies offering auto conversions of every description, from every manufacturer imaginable, for me it boils down to a single engine type – the tried and tested VW.  And there are only three places to get your VW conversion – again, my personal opinion.  The first is Aerovee (a subsidiary of Sonex Aircraft), the second is Revmaster, and the third is Great Plains Aircraft.
    Aerovee:     http://www.aeroconversions.com/products/aerovee/index.html

  • This is a lovely engine, and in our opinion, the best on the market today for the home builder – bar none.  80hp, 161lbs.  You buy it in parts, and assemble it yourself, working from an assembly manual, and a video.  Even I can do it.

    Aerovee also offer all sorts of add-on goodies, like throttle quadrants, optional Nikasil Cylinder upgrade (saves 10lbs) and there is an active online support group at Yahoo Groups.  One of these will set you back about $6,500 (USD)

    Great Plains:
    http://www.greatplainsas.com/
    Theyoffer three variants, so you get to choose between front drive, reduction drive and flywheel drive versions.  Prices, power and reputation about the same as Aerovee.  Only hassle is you can’t just buy an engine,  You have to work your way through their options and “build-up” your engine bits from all their options.  I found it quite confusing. Theyoffer three variants, so you get to choose between front drive, reduction drive and flywheel drive versions.  Cost?  About the same as the Aerovee.

    Revmaster:
    http://www.revmasteraviation.com/
    Not QUITE as pretty as the AeroVee, but this is a very sweet engine.  There is almost nothing of the original VW engine left in this built-from-the-ground-up aero engine.  Special crank, extra bearing at the prop hub, custom pistons, conrods, compression chamber etc etc.  AND you can use any prop you like, including composite or even metal props.  The more I think about it, the more I like this engine.  85hp take-off power, 80hp continuous.  170lbs.  Cost:  about $7,000 (USD)

    BMW
    And a very fond word reserved for the BMW motorcycle conversions…
    Both the R1150 and R1200 series horisontally opposed engines are frequently used in aircraft.  Mainly because you just can’t break them.  They have dollops of torque, gobs of HP and they will run forever.

    The K-series engines are also great little powerplants.  The K-75 (750cc) weighs in at 185lbs fully oiled, and fitted with a Rotax gearbox.  It produces 73hp, and is just about bullet-proof.  Great engines to turbo, since they will take 8lbs of boost without blinking an eyelid, and suddenly you have a reliable turbo aero engine, capable of cruising at its full 110hp all the way up to 10k feet.  One of the problems with these motors is that they can’t be bought off the shelf.  These are all one-offs, and you need to know what you’re doing.  This is not an option if you want an easy solution.

  • INDUSTRIAL engines
    Now this is where it gets REALLY interesting.  If you don’t need a lot of power (ie under 40hp) then one of these might just do the trick.  The idea is relatively new, but there are already two companies which specialise in aero-converting these little workhorses.  (Valley Engineering (US-based) and Soloflight (in the UK).

 

  • Locally rebuilt 49 ci B&S lawn motor engines:
    I seem to have stumbled across a real find.  I was browsing the web recently, and came across racing lawnmowers, of all things.  I checked out the Aussie scene only to find that the sport is alive and thriving here downunder.  So I got in contact with one of the engine rebuilders who support the sport, and it turns out that they take new 49 ci engines (800cc) strip the entire thing down, replace just about every critical component with race-spec parts and can hand over to you an engine capable of anything up to 98hp.  Reliability?  I am told that some racers who rev their engines to 8000 on a routine basis have been racing for over 10 years without a rebuild.  Cost?  All-up, built and tested = $6k AUD.  And if you are in the US, you can probably knock off a good $2k from that because there will be no international freight or import dutyto pay.

[Added: 25 May 2015]
This is a post I found on the SD1 forum in the UK.  It is so good, I decided to copy the entire thing here. (Thanks Paul):

Hi people, I’m Paul from NZ,
I love the look of this beautiful aircraft and it looks well manufactured.I have been surfing the internet for some alternative engine info.

Someone mentioned the aerotwin engine,at 90lbs plus 27lbs for the gearbox it looks a little too heavy.They do show a belt drive but no weight numbers.Beautiful engine though.Here it is with all its bits on.http://www.aerotwinnz.co.nz/, might need a smaller prop!

I also found this, http://mudboatmotor.com/html/vangaurd_23hp.html ,These guys tweak these engines to gain a little more hp and torque.As these engines are made to slog all day I think there is plenty of scope for improvement without worries about reliability.

They also say they can improve other engines like the Kohler, http://www.kohlerengines.com/onlinecata … es=Command PRO EFI . or the Subaru, http://robinamerica.com/pfeatures.aspx?pid=225 .This engine has automatic altitude compensating EFI to 9800ft. 35hp at sea level out of that would be great.
These guys make belt reduction drives which could lift the v-twin prop height, http://aerotech-poland.com/index.php?go=14 .

This has also sparked my interest, http://www.parajet.com/paramotors/cyclone/ ,The UK dealer says you can buy the engine alone for between 3500 and 4500 pounds.It’s 40hp weighs 22.4 kg plus radiator hoses etc. It produces 92kg of thrust from a 125 cm prop.It is very popular in the karting world, http://www.renntechkarting.com/products_xr50.html , and has a vid of aircraft application here,http://www.renntechkarting.com/media_videos_xf40.html ,Unfortunately I have tried to contact the NZ distributor but have had no reply.Not a good start.I understand they generate a fair amount of heat and I’m not sure on the fuel use.

http://www.renntechmercedes.com/www/node/540
On the two stroke front there is this, http://www.compactradialengines.com/mz202.html .It is a little too powerful but if used below max rpm would generate 45 odd hp at max torque and be reliable.Governed perhaps!

Hirth have been trying to improve their image over the last 3 years by making low rpm high torque engines that are reliable.They say they are virtually unseizable.Don’t read the disclaimer it says otherwise.This one looks perfect, http://www.recpower.com/2702%202%20cycle%2040hp.htm , Lower rpm might be a way of keeping them reliable.They also claim comparable fuel usage to a four stroke.A reliable two stroke with low fuel use would be a winner.Also water cooled version in weight range, http://www.hirth-motoren.de/en/engine-3502.html .

There is also this if you like the smell of jet fuel, http://www.2si.com/460_mf_spec.htm  Once all the bits are added it becomes a little too heavy?

The JCV 360 appears to be one of the best applications so far as it is a simple bolt on engine and all the hard work has been done.Not quite sure on the cowl cheeks,would prefer the stremlined look of the original.But as simplicity goes,you would be flying quicker.I would love to see the performance figures for the german JCV360 engined SD1.

Just some rough notes,If anybody has any thoughts please jot them down.I have very little experience with alternative engines so the easiest and most reliable option will probably be the best for me,
Regards Paul.