http://www.sauer-flugmotorenbau.de/Vier ... troke.html
None of them match your description...
Also, remember that the job of an aero engine is to turn a propeller. And for a propeller to be efficient, you don't want to turn it faster than around 2700RPM in the cruise. So there are two main designs of aero engine. Direct drive, where you have a large capacity engine turning at prop speed (max ~3000RPM), or reduction drive, where you turn a small engine really fast, and use some sort of reduction (gear/belt) to turn the prop at a slower speed.
Now adding a reduction drive adds weight, and so does increasing capacity. It just so happens that the thermal limits of VW heads mean you can't really get enough power out of them to make a redrive worth its weight, so most manufacturers tend to increase capacity. Which explains a lot of the design decisions you are complaining about.
As to the power levels, well the specific power is pretty much the same as every direct drive aero engine out there (Jabiru, UL, Lycoming, Continental, Franklin, etc.). They all make almost the same hp/cc - so the power is just where it should be.
Turbo wrote:justin.schoeman wrote:Seems you really have something against Revmaster, Turbo... But you really should do more research before you start your rant. Revmaster doesn't use Chinese parts (or not many). Almost all of their parts are either manufactured in-house, or at local american factories. Almost none of the parts are 'copies' of the original VW, as none of the original VW parts were made to these dimensions. [No different from the Sauer, which is also a 'copy' of the VW.] nope nothing against revmaster at all, and no rant either -- that you dont want to seeall im doing is explaining facts for facts - the parts ARE made in china, along side the procomp, speedpro and BC conrods -- I HAVE SEEN THEM MYSELF LAST YEAR NOVEMBER AT AUTOMECHANIKA - EVERYTHING is outsourced to China when it comes to castings, materials and other, otherwise the pricing for local manufacturing would be far too high!
Did you actually see parts labelled 'Revmaster' there. Joe has a very good reputation, and I doubt he would lie about it.
secondly - my research and knowledge on this topic far exceeds most and in this case, please examine the block and other outside components ASWELL AS the oiling system aswell as almost everything else In this engine -- its VW -- fact!
Yes - I did say that it has a stock VW case and cam bearings...
As I said above - it looks like there is some other 'Sauer' engine out there...Regards Suaer - I never knew VW had a 700cc engine.... I never knew that they made a water cooled version .... VW I think not! - once again nothing but FACT.
For aviation you want a low revving engine - hence the very specific 'aviation' grind that isn't use in any automotive engines.The cam grind is optimised for aviation use, as it is designed for a torque band in the 2300-2800RPM range (unlike the off-the shelf VW cams that make their best torque around 3600RPM. I suggest you read my comment about cams above, you might see your contradiction -- secondly what happened to the overlap (scavenging effect when grinding the cam to operate at such a low RPM level -- GONE -- that's what. Hence my comment about the pipes -- which we will come to later
Which is the whole point - you make it cost effective by using as much existing technology as you can. And the object isn't to increase the RPM band - it is to decrease it to the point where you can efficiently drive a propeller without a gearbox. Which is exactly what all these design decisions achieve.The stroke is longer, yes - but the bore/stroke ratio is still pretty much the same, same as VW yes.as the bore is increased at the same time. yes obviously so that they get the larger 2300cc - correct The rod ratio is in fact better, as the rods were lengthened more than the stroke. is that why it makes so little power? Is that also why the TBO is so low? the rod ratio on this engine is not good for longevity, nor is it good for ultimate performance, let me explain. the short MOVEMENT of the piston and rod lowers torque and power, AND extends the operating RPM band - which is not used, therefore producing the tiny power output that the engine does. For example - the F1 engines have a 20mm stroke and rev to over 20 000RPM in some cases but make hardly any power in comparison to lets say a beefy 598CI V8 ---- BUT because this is a glorified VW motor, they would not have gone and re-invented the wheel to make a new engine ... or else it would have been comparable (and expensive) to the Rotax, instead it is a glorified VW beetle engine
As before - some other 'Sauer'...[Bore and stroke are the same as Sauer.] same as they Sauer -- which one of the 5 models?
The prop rotates clockwise, so you [need] a left hand bolt to secure it properly.Rather than try to machine a chinese crank to work, they have their own crank forged,I know -- IN CHINA -- I have seen it personally so they can use bigger journals and bearings, and machine them for the left hand thread,haha left hand thread on a left hand rotating component... Ill use a silly example - on a turbocharger where the rotation is clockwise, and the nut tightens anticlockwise and vice versa.
You missed the point. Other manufactures either use the existing right hand thread, or drill it out and fit a bigger bolt. Revmater does it properly by using a full custom crank.without having to drill out the whole thing, and weaken it.that's no engineering marvel, even the old 1928 ford T-bucket engines threaded the output shaft, but they were a step ahead of Revmaster and many other engine manufacturers too -- they cold roll their threads - and revmaster cut them
You may not like 4340, but there has never been a Revmaster crankshaft failure - so obviously the material is more than adequate for the task.on the contrary, I love 4340 for its intended purpose - IT IS NOT SUCH A FANTASTIC FEATURE AS JUSTIN PUT IT,
I didn't say it was a fantastic feature. Jean Crous listed it as one of the marketing features. And if you know anything about the VW market, you will realise that this is to differentiate it from the no-name Chinese stuff and 4140 cranks that are on the market (the majority of them). I was just correcting you when you said it was not chromolly - when just about every steel supplier on the web lists it as a chromolly steel.
instead its the norm, of which even the Renault Twingo uses this for its crank and rods.... -- I have always loved 4340 - my own brand of con-rods I manufactured on my own CNC machine in 2003 were made from 4340, and the heat treatment was done incorrectly, my mistake, and school fees learned check below for pics - and if you look closely you will see the crack on the outside of the side journal case of the rod due to incorrect hardening -- and to comment on the revmaster failure aspects -- it CANT fail, its overdesigned, I have not commented against their design at all -- but that engine doesn't make enough power to pull itself out of a wet paper bag, so obviously it will never fail.... the question you should be asking is this - why is the TBO so low compared to Rotax 2000hours - aswell as ROTEC, SAUER, VERNON etc so much longer, with SMALLER ENGINES?
The engines aren't certified, so they have no TBO. Sauer and Limbach (who sell certified VW derivatives) list TBO as 1600 hours - so I expect you can get the same out of a Revmaster.
Dealt with above.- I can tell you why -- the overall design of the revmaster engine is lacking because it is a glorified VW beetle engine
Yes - it is an oddball standard, used by some backwater companies - which is why I suppose the standard is called 'AS' (American Standard). You can find some of the details on common AS grades in this document (from page 4 onwards):The four digit aluminium alloy numbers are used for a specific range of alloys. 356 is a real aluminium alloy. I also cast my own grade of aluminium, its called LION .... or was it cheetah -- hehe im getting sarcastic now, as without a composition or specification the numbers 356 mean absolutely nothing. ALL aluminium materials have a designation - like AISI, ASTM etc, and most of them are American products. some have called their aluminium 2123ally -- which has no OFFICIAL designation in a metallurgists handbook or such -- here is an example - Ferrari recently "invented a new material called CARBOTANIUM - its the threaded weave of titanium and carbon fibre -- this also does not exist in any documented handbook as it is NOT accepted as an official material. So neither is my LION ally either - but who says its not strong - who says it isn't porous either?? Unless the material has an official designation/specification, it cannot be measured, tested, or controlled in a QC format -- yet another reason why Revmaster is so much cheaper than rotax -- which is a good thing -- or is it?
http://www.mid-atlanticcasting.com/alum ... _FEB05.pdf
Straight pipes are not perfect for performance. A properly tuned 4 into 1 will scavenge a lot better than straight pipes. They said nothing about adding a silencer (which would, indeed reduce power).HAHAHAHA how many engines have you built? How many have you tuned on an engine dyno? How many of these engines have you set cam timing on? How many engines have you requested a SPECIFIC grind cam for a specific engine?? I have done all of the above more than 20 times in my life, and if you switch on the TV and you see the local T-class production series race cars, driven by Formato, Prinsloo, Nathan, Pepper etc -- I personally built every single one of those turbochargers on every single one f those cars, and continue to do so every year - I have also been involved with two of these teams in developing cams and other means of making HP to overcome the 36mm restirctors placed in front of the turbos -- I believe I know a tiny little bit about cams, and maybe engines too.... in this specific revaster engine - they HAD to grind a custom cam because the engine has to LABOUR along at such a low RPM (that's why they have low TBO's - rich mixtures due to a labouring engine!!)http://www.mid-atlanticcasting.com/alum ... _FEB05.pdf
The engine isn't labouring, or over-rich. The entire engine is optimised to run at these speeds.
Yup - not much performance change - Jean actually gave you the dyno numbers - ~3% max improvement.and because of this the cam had to operate in the low RPM band, hence there will be absolutely no power difference between a staged diameter exhaust or a straight cut pipe out of this engine (read above for the disappearing act in the overlap - think V-tec 9000RPM and the CAM that the V-tec controlled ... get my drift?) its like fitting a performance pipe to your lawnmower - no increase in power, revs too low and cam grind will not allow scavenging! - second to this - how many performance pipes do you see being fitted to Continentals, Lycomings -- hardly any because they yield almost no performance increase - and these are BIG engines!
Look up Power Flow Systems for certified tuned exhausts for Continentals and Lycomings.
Yes - it has its place - as a pretty decent value for money replacement for the Rotax 912.The engine may not seem innovative to you, but it seems you have not really looked at VW designs, and the history of them. Revmaster has been in the game the longest of all the VW aftermarket manufacturers. Oh so it is a VW engine ... OK Im with you Many of the innovations were developed by them, and copied by others (like the #4 bearing - which has even been copied by Limbach and Sauer). Never mind all the other tweaks, like moving the thrust bearing, flanged flywheel fittings, etc...Hey im not saying that revmaster is a bad engine at all -- BUT in comparison to others, it barely holds its own. Every engine has its place, but my initial comment which led astray here - was that Rotax is a rip off and they are -- and that comparing apples with apples, surely there should be alternatives VALUE FOR MONEY -- Revmaster has its place, but not in my hangar, as I know a little bit more than the next guy about these components and in my opinion (opinions are like arseholes, everyone's got one) I think they suck.... That's not to say I would buy a Sauer either, I was simply using Sauer as a comparison that's all. Hell we can talk about Vernon too if you like - and that ENTIRE ENGINE is manufactured by Jinchecg in China -- yet its TBO is so high ..... mmmhhh 4340 -- full up!
As before, that is the other strategy for aero engines - small, fast and use a gearbox...As to the power - yes, you can get 100hp out of a stock VW - but at very high revsout of a 1600cc engine with lightened components.... etc etc, so you need to add 13kg worth of reduction drive before you can turn a prop. For direct drive at prop RPMS, you are stuck at the same power levels. Which is why all the VW manufacturers (including Sauer and Limbach) have pretty much the same power ratings for the same bore and stroke.i think not - Sauer makes ALOT more power 115HP to be exact out of the smaller engine (yes turbo) and a lot more torque with the same weight ... AND its watercooled.... go figure
OK - with your own workshop, you could possibly make it for that price - put could you sell it and still make a profit?And why do you say the Revmaster price is hefty? You can put together a 94x84 VW long block for around USD5000 using cheap chinese parts, and then you need to start with custom cranks, prop flanges and accessories.no sir - not cheap Chinese parts - Procomp, BC, or even Carrillo -- OOPPS they made in china.... and YES I can - in fact ii can build you a BILLETT (from top to bottom) VW long block for LESS than $5000.00 but who in their right mind would spend that money to make the power that a brand new 4 cyl 2 stroke engine with ALL components included will make?
You can do a full overhaul of the Revmaster for about R5000. TBO could be 100 hours, and you would still be ahead of the Rotax!All in all, the Revmaster R2300 and Sauer S2400 are pretty much directly comparable in terms of weight and performance. Both will be good replacements for a Rotax 912 - with the advantage of a 5kg saving in total firewall forward weight (yes, they are indeed lighter than the Rotax when you calculate the full FWF weight). what about TBO -- ?? Sauer is longer, therefore less money - furthermore, ROTAX further life still -- MORE savings.....
Again - different 'Sauer' engine.This makes the Revmaster R2300 the most affordable 4 stroke option at the moment, by quite a margin.taking into account the TBO and costs to rebuild the revmaser its NOT cheaper by a long shot. Sauer is, and performs ALOT better than the revmaster, and is available water cooled, and longer TBO, and turbocharged also -- more options, german engineering, long TBO, proven in many oem applications, etc etc
Are you sure you aren't referring to Sauer's M800 project (750cc twin in-line turbo 4 stroke engine)? If so - they abandoned that project, because they couldn't get TV under control. One of the disadvantages of a small high revving engine + gearbox combo...
..... I saw the Sauer up close at Aero-Friedrichshafen in 2012 and must say it is a nice engine. The Revmaster is in my opinion better value for money. 
