Originally Posted by Twin-Stack

With the benefit now of around 30 years of hindsight, can I pose these three question to all Diesel lovers........
1) Was there any real advantage in having a Schnuerle ported Diesel ?
2) Was there any real advantage in having a Diesel with ABC metalurgy ?
3) Was there any real advantage employing both of the above technologies together in a model Diesel engine ?

Considering that all modern F2C engines are using these technologies and newer: AAC and integral cylinder/liner/head, yes there is benefit. How does the performance and fuel consumption of an Oliver or ETA compare to a modern F2C engine? Does it really offer much benefit outside F2C? In general for sport use I doubt anyone sees any difference, except maybe consumption which few bother with anyway. The weight of a modern F2C engine is amazing, but of no use to a sport flier that might see an occasional mishap.

Diesel users accept a lot of castor oil in fuel as standard. With a chromed liner and high silicon piston, the oil content could be reduced and mostly, or all synthetic.

Greg

Originally Posted by 2gun

I am considering a typical Schneurle ported engine here. I think that it is a combination of the two. If the liner was only a few thou thick, but the ports matched the bypasses then the bypass would be the only important thing to set the flow direction. However if the liner is say 1/16th thick, but the ports in the liner are not cut at the correct angle to match the bypass angle (perhaps just milled in radially), then you will probably get all sorts of turbulence at the port causing disruption to the required loop flow of the gas. Another thing ( off topic and unrelated to port angles) is the internal finish of the gas passages. In my opinion, although smoothness and flow direction is important, polishing is not. I think that the best surface is about like fine bead blasting. Mind you there is no guarantee that I am right.
Charlie

Charlie, what got me thinking about all this is, I've just bought an Enya 49X, which is basically a bored-out Enya 45X, which is basically a bored and stroked Enya 40X ! I was thinking maybe as the bore got bigger, the efficiency of the Schnuerle ports grew smaller ! I will point out here that Enya used probably the ultimate in piston/liner metalurgy, their version of AAC called Al-Chrome which is superb, but expensive. Strangely perhaps, some engines had it while others didn't, as witness this quote - " The 45X-TV was described in the March 1981 issue as being based on the 40X, but with the bore increased by 0.7mm and the stroke by 1.5mm. The most major change from the 40X however, was the switch from a steel liner & Dykes ring, to the AAC set-up, which not only meant the larger engine was lighter in weight, despite the increased size, but had a more efficient gas flow system due to a thicker (alloy) liner."

Originally Posted by Twin-Stack

Charlie, what got me thinking about all this is, I've just bought an Enya 49X, which is basically a bored-out Enya 45X, which is basically a bored and stroked Enya 40X ! I was thinking maybe as the bore got bigger, the efficiency of the Schnuerle ports grew smaller ! I will point out here that Enya used probably the ultimate in piston/liner metalurgy, their version of AAC called Al-Chrome which is superb, but expensive. Strangely perhaps, some engines had it while others didn't, as witness this quote - " The 45X-TV was described in the March 1981 issue as being based on the 40X, but with the bore increased by 0.7mm and the stroke by 1.5mm. The most major change from the 40X however, was the switch from a steel liner & Dykes ring, to the AAC set-up, which not only meant the larger engine was lighter in weight, despite the increased size, but had a more efficient gas flow system due to a thicker (alloy) liner."

Bob, I expect a good part of the improvement to gas flow would be the elimination of the ring retaining bars in the ports. Thickness of the liner should help with keeping the thing round and as long as it was cut at the same angle as the bypasses the flow direction would be improved over a ringed engine.
Charlie

Thanks Sundancer. I kind of felt you were going to say the Cox had it every time, but I didn’t want to. When I get time, I’ll find the parts and show you what happened to my Conquest. Presently I’ve got a TD .09 in a 32 oz Wild Thing and it is almost good for unlimited vertical. When I was younger, my free flights were mostly hit and miss, as I didn’t know how to properly trim them (probably still don’t!). I once had a small 1/2A free flight that did about three torque rolls before hitting the ground- first and last flight. Had another that I almost lost as it powered steeply up on a full tank. Life’s hard lessons.
Yes, it’s hard to beat a free flight on a very calm evening just drifting around lazily. It’s been a very long time!

Try looking into the "products" of the Frenchman A. Morin who sold designs & drawings for 1940s diesels like this one. They were therefore all built by amateurs & not mass produced which may account for the odd selection of materials & screw threads. It may also be incomplete because the model engineer did not have the necessary skill!

Originally Posted by hughmcq

Try looking into the "products" of the Frenchman A. Morin who sold designs & drawings for 1940s diesels like this one. They were therefore all built by amateurs & not mass produced which may account for the odd selection of materials & screw threads. It may also be incomplete because the model engineer did not have the necessary skill!

Do you have a link for that designer history?

Originally Posted by coriolan

Do you have a link for that designer history?

Corio here's one of his engines. I also have a catalogue and stuff that I can dig out.
André Morin really was "ahead of his time". A few years ago (in the sixties!), I used to think that Duke Fox was really ahead because his Golden RatRace .40 had a ball race at the rear end of the crankshaft, and a needle bearing at the front... Well this Morin 10cc fixed compression diesel had exactly the same arrangement, in the mid-forties... A super engine.
Brian

Thank you brokenenglish for the infos, there seems to have been many small French company after the war(Allouchery,Rea,Stab etc...)which disappeared soon after in the 50's. There is also lot of obscure engines from Sweeden,Germany,Switzerland,Belgium to mention a few countries. Found some details about this 10cc single diesel in an old post:
http://www.rcgroups.com/forums/showp...&postcount=527

Brian, Any more info on the Morin 10 cc diesel? Jack

There is a little bit on "Modelenginenews(half way down the page)
Le Moteur functionnant
en auto-allumange:
click on "show the answer" for details

http://modelenginenews.org/watzit/p6.html
The plan only was 75 Fr and casting were available from Mr A. Morin in Aubervillier(a suburb of Paris)

Originally Posted by coriolan

There is a little bit on "Modelenginenews(half way down the page)
Le Moteur functionnant
en auto-allumange:
click on "show the answer" for details

http://modelenginenews.org/watzit/p6.html
The plan only was 75 Fr and casting were available from Mr A. Morin in Aubervillier(a suburb of Paris)

I remember seeing these photos on Ron's site. If I remember rightly, the engine was found in a junk shop by an English collector on vacation in France (lucky!!!). From the photos, the prop. driver obviously differs from A. Morin's original drawing, and looks more recent.
For Jack, from memory, I think Morin's original specification included a magnesium crankcase casting (on a .60 diesel!). However, mine, and the other couple or 3 that I've seen over the last 40 years, have a normal alloy crankcase (good!). Even so, the case appears fairly fine and delicate. You'll see that even the mounting lugs have been lightened (again, on a .60 diesel!!!). Mine runs well (I run, or try to run, all my engines), but I don't think I'd risk flying it (which I also try to do when it seems reasonable).
If you care to look on the glow or spark ignition threads, a couple of months back, JMP_Blackfoot and Raduga posted some interesting stuff on a Morin twin.
Brian

Hello,
I am very interested in your comments about the Enya 4 stroke, in particular the aspect of the engine having no contra piston and relying on the use of shims (I suppose this is because it is too hard to organise with valves). Can you please confirm that the shims are placed on the threaded insert (which takes the place of the glow plug) and does not entail the removal of the whole head. Thanks, George.

Originally Posted by George O

Hello,
I am very interested in your comments about the Enya 4 stroke, in particular the aspect of the engine having no contra piston and relying on the use of shims (I suppose this is because it is too hard to organise with valves). Can you please confirm that the shims are placed on the threaded insert (which takes the place of the glow plug) and does not entail the removal of the whole head. Thanks, George.

Hi George,
You raise an interesting point. When reading the instructions, about a year ago, I was left with the impression that the whole head was shimmed. However, this doesn't seem very convenient on a 4st, so I suppose I could have made a mistake. I have Neil Tidey's Laser 75 diesel, and that uses a normal type contra-piston, but only in a small area of the head, left clear by the valves. I suppose that contra-piston could be replaced by a plug arrangement with variable shims (on the Enya). However, you must have read all this on Chris Jenkins' "Albert Hatfull" thread. Perhaps you should contact Chris on that thread, as he actually owns an Enya, so he'll be able to answer you for sure. I'm only reasoning based on my own fixed compression experience, and I'd like to know the answer to your question as well!
Brian

Thanks Brian and coriolan for the info on th 10 cc Morin. Jack

The Enya is supplied with head shims. Some of the magazine reviews make mention of adding an extra washer under the dummy plug for fine tuning of the compression ratio. Quite honestly that doesn't change the volume enough to make any difference you can't already compensate for with the needle. Most people actually flying the Enya 41-4CD say once you've chosen a prop and shimmed the head for it, if needed, it doesn't need compression adjustment. I have not flown mine, but have been using my own OS four stroke diesel conversions, but have found those require some compression adjustment. But I think the compression adjuster I'm using actually makes them more sensitive to compression ratio, with engines over 7.5cc or so.

Greg