1/2 VW turbo charged

[Raffus]

Has anyone attempted putting a turbo on a 1/2 VW.   

[scottiniowa]

Has anyone attempted putting a turbo on a 1/2 VW.

A few things come to mind, and I know this does not answer the base question.

But that would be a tiny one for a 1/2 VW but I suppose they are out there.
Perhaps they are not that complicated, but then again, it could not be as simple as the base aircraft…

zoom zoom
Scott

[Tom XL-7]

I am not aware of any turbo 1/2 VW
What came to my mind was how much does the unit weigh with all the extra plumbing.  If the completed half approaches or exceeds a light 4 cylinder VW
Then the four is the way to go. 
The four builds easier. Is better balanced and while the crankcase volume shifts from front to back, it is balanced. The 1/2 is always sucking or blowing due to the increase in crankcase volume on the out stokes and the decrease on the inward strokes. There are a few methods to tame it but it is another issue to deal with.
 The 1/2 VW is an amazingly successful way to bring 4 stroke power to ultralights. The 45 horse 1/2 delivers more than enough for any legal ultralight. 
 There is always room for experimentation.

[massmanute]

I have been wondering the same thing.

One of the problems would be proper sizing of the turbocharger. In looking around at what is available I think a Garrett type GT0632SZ might work. It is intended for small engines.

The turbo map has a peak at a corrected air flow of about 5.1 lb/min at a boost ratio of about 2.1.

http://www.limitengineering.com/Turbos/GT0632SZ/GT0632SZ%20Compressor%20Map.jpg

I think that 5 lb/min is pretty close to what an 800cc engine turning at 3400 rpm at full throttle and a boost ratio of 2 would produce, so maybe the sizing is OK, although one would have to carefully consider whether there is a risk of the turbo going into surge at part throttle.

I think this combination could produce something close to 60 hp. This raises the question of whether it would make too much horsepower, giving the aircraft too much performance (55 knots for part 103). However, for an aircraft that does not meet part 103 it could be just the ticket. I'm thinking of a high wing version of a TEAM aircraft for example.

Another question is whether 60 horsepower might stress the engine components too much. Given the fact that the crankshaft would be shortened, it seems likely that the issue of torsional vibration would be less of a threat, so at least that is a factor going in our favor.

Another issue is whether there would be overheating of the cylinder head.

Another issue is the risk of detonation. However, shimming the cylinders to lower the compression ratio might handle that issue. Also, a waste gate might help.

Here's a relevant link to this turbocharger.

http://www.limitengineering.com/Turbos/GT0632SZ/GT0632SZ.html

[Golden Eagle]

I realize this subject is a few months old, but I just found it doing a search.

A couple of you guys made some interesting observations.  I’d like to add a couple of thoughts if I can.

Of course a turbocharger added onto a 1/2 VW would need to be small.  Probably as small as they come.  The French have a small turbo that goes on a Citroen engine.  (See link at the bottom). The price is right, that’s for sure.  I checked on its weight, and it is 9 lbs 10 oz like you see in the picture.  The Garrett would be similar in weight, but from where I was searching (eBay) it was going for $700+ or so.  I think the Citroen one would do.

You would need to add a couple more pounds for the other peripheral things that go with a turbo, like oil lines, and ducting, etc.  Let’s just say the whole thing came to 15 lbs installed.  Is a 15 lb weight penalty worth an easy 40-50% more power?  To many car builders, absolutely.  To airplane builders, it depends on a lot of things.  I think to some of us heavy-weights, possibly. 

There is a close relationship to the amount of added boost to the power output.  Meaning:  1/2 more air and fuel over a normally aspirated engine results in 1/2 more HP.  Since normal air pressure at sea level is 14.9 psi, if we added ~ 5psi boost, our engine would produce approx. 1/3 more HP. (Assuming a proper F/A ratio.  Specifically, if we had a 40 HP 1/2 VW engine (weighing in at 90#) and we added 1/3rd X 40 = 13 more HP, we’d be somewhere in the neighborhood of 53 HP at a cost of 15 lbs added weight.  (40 HP @ 90# vs 53 HP @ 105#).   I think this is a viable option if done correctly.   BTW, adding 1/3 more Air/fuel (in the form of boost) would likely have almost zero effect on the durability of our typical 1/2 VW engine.  There are lots of Baja buggies putting out 200 to 300 HP for the full 4 cylinders, or if we split that in half, 100-150 HP if it were a 2 cylinder motor.   Pushing a 1/2 VW engine to 60 HP “ain’t much!”.

I did my own custom installation of a turbocharger to a GEO Metro 3 cylinder 1000cc engine on my Kolb MkIII Xtra.  I used a little dinky Garrett GT3 turbo and fabricated all of the exhaust and ductwork.  It is a little bit of fabrication to get it right, but not too much work for many guys.

The subject of a wastegate was mentioned.  As far I have ever seen, all of the small turbos come with a built in wastegate, so an over boosted engine is highly unlikely.  Also, due to the typical nature of SLOW throttle changes in an airplane, their installations of a turbo would NEVER need a blow-off valve. 

One more thought:  As a general rule, airplane engines have three setting that they adhere to most of the time.  There is idle, climb out, and cruise.  Of course there can always be some variation, but for the most part, that describes most of them. This limited rpm variation lends itself very well to turbocharging.  Here is an example:  Since an airplane engine’s rpms are expected to be set at a cruise setting for most of its “life”, that rpm setting is perfect for a lightly boosted engine.  As an example, if a guy set his cruise rpm to be, let’s say 3000 rpm, then he would be barely in the boost range of a (properly tuned) turbo.  In most situations, this guy could actually reduce his rpms (meaning much quieter prop and exhaust noise) over the non-turboed engine and save on fuel and simply by adding a turbo, the exhaust noise alone would be significantly lowered.  There ARE several benefits to having a turbocharged engine.  Getting it set up right is the key.

If a guy can be satisfied and can live with a legal 254 lb plane and a normally aspirated 1/2 VW engine, then he has the good fortune of being able to build a stock Legal Eagle.  But for some, an Eagle XL with a turbocharged 1/2 VW (and paying a 15 lb weight penalty) could be quite viable.  If anyone would like to discuss this idea with me, please feel free to contact me, both in on this venue, or private message me.  In the meantime, take a look at this:

https://www.ebay.com/itm/TCT-KP35-Turbocharger-for-Citroen-C1-C2-C3-Xsara-1-4-HDi-DV4TD-54HP-40kw/263425886398?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

[massmanute]

Hi Golden Eagle.

Could you add the link to the Citroen turbo?

Thanks.

[Golden Eagle]

Yes.  Oops.  Missed it until I reviewed my post.

[CHARLES DEBOER]

Please don't forget that the LEU and the LEXL was designed to the take the aero dynamic forces of a 40 hp motor.  Anything over that design limit could be fatal.

[massmanute]

To add one more question, or maybe a non-required complication, would an intercooler be worth considering... more weight would of course be understood, and how to fit it into an aircraft is another complication, cut it would at least provide more effective boost.

[Golden Eagle]

I think an intercooler might help some, but I think a guy would have to make his own.  Even the little bitty intercooler I used off of a Chevy Sprint 3 cylinder was more bulky that you’d probably want on a plane.  I think if I were to use one I would make one out of paper-thin aluminum and be happy with even just the slightest bit of cooling from it.  Remember, we aren’t looking at very much boost (compressed air).  Only 1/2 atmospheres, or 8 psi at most.  There isn’t a whole of heat generated with that much compression.  Some, but not a lot.  Probably not much more than the exhaust of a typical vacuum cleaner.  I’d be tempted to leave the intercooler off, and at that point, not worry about carb ice, either.

Mike

[MontanaMan]

Funny ... I was just thinking about turbocharging my Hummel 1/2.  I don't know much about this, but what about the little motorcycle turbochargers?  They might give less boost, but something like that would be so much smaller and lighter, yet still deliver maybe another 7 or 8 hp.  

https://www.ebay.com/itm/322658385789

Honestly, I'm surprised none of the 4-stroke makers haven't specifically designed a small, radial, turbo-charged engine.  I think if done right you could get 40 HP at 55 lbs or so.

Just a thought.

[Golden Eagle]

Yes, I think that motorcycle turbo would be about the right size, but I also think so is the Citroen turbo I showed.  If you could get the genuine brand of motorcycle turbo rather than the Chinese imitation then I think you would be on the right path, but I would be very hesitant about using a Chinese manufactured turbocharger, even though the Chinese are known for their incredibly high quality machinery parts, and tools, too.

Mike

[MontanaMan]

I would be very hesitant about using a Chinese manufactured turbocharger, even though the Chinese are known for their incredibly high quality machinery parts, and tools, too. Mike

LOL ... I agree.  I wasn't recommending that specific item, just the concept of the smaller, motorcycle-specific turbo.  I've had so many problems with Chinese junk, I would think even a used OEM part would be much more reliable than a new Chinese part.  

I would *never* trust my life to anything made in China.  That's the problem with many of the older, discontinued Rotax motors ... they are being repaired or rebuilt with cheapo aftermarket parts, and many times the people selling them don't even know where the parts came from.

[Theodore]

Turbo on a 1/2 vw bad idea, turbos are cooled with oil that gravity drains back into the case, so placment is on top of engine, imagine all the piping intake and exhaust that will add weight and drag.

[Golden Eagle]

I don’t necessarily agree.  The total weight for a tiny turbocharger could come in at about 10-12 lbs.  “IF” you could afford the added weight, you could gain an easy 10-15 HP.  I’m not saying it is a good idea, but I think it could be done.

Cheers, Mike