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geoffreywh

D-Motor

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They should be close together if the timing won't be miles out with single mag ops. Putting the plug above the exhaust valve doesn't promote the smoothest running for some reason. This could be associated with mixture distribution and be less of a problem with injection. It's quite likely that the plugs should be a different heat range also because of their placement. In most aero engines they are wide apart in the combustion chamber , probably to reduce the total time to burn all the charge and thereby use less advance on the timing. Nev

 

 

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One day Nev, you really have to share your aviation history with us all in a more complete sense. It really deserves it's own thread.

 

 

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Thanks B 12 . There's plenty of others with tales to tell. Mine are fairly ordinary apart from the ones which would be looked at as being made up. We are in a different world from when I started. It's only about 107 years since powered flight was possible.. When people saw the DC3 in 1936 OTA they reckoned it would be too heavy to get off the ground. Nev

 

 

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Interesting to read the theories on plug placement from nev and bex which make sense, but I reckon most small a/c engines are the same layout. I can see the inlet plug getting wet from the incoming mixture, but isn't the best position determined by the mixture flow and turbulence from any squish areas when both valves are closed and aiming for an ideal burn? Does knock or detonation come into this as well?

 

Yes, the plugs are both the same heat range as they are in Jabiru, Rotax and Verner, the only other twin plug engines I have experience on. Would you suggest hotter plugs by the inlet?

 

I will ask if I can post a photo of the insides and see if you can spot one of the design tricks.

 

I guess I should have known better about the last line! You are probably aware that many bankers and property gangsters over here quite deliberately sold faulty products.

 

 

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Detonation is not too likely with a sidevalve. You can't get high compression without restricting airflow and losing power that way. The reason to start the fire in the hot place is that there is less chance of detonation, as the flame front advances it is going to the cooler part which is desired to stop the whole lot burning in a rush cause it compresses as it burns..

 

The most common place for a sidevalve single plug location is pretty much over the inlet valve and they usually don't run a cooler plug than an OHV of the same size. Revs and load affect the heat range, more revs appearing to heat the plug more. ( Which is logical I suppose). Most of the "tricks" involve gas flow in the head , squish areas and your approach to flow through the ports. Some have the valve almost touching the head and the gas flows out the side rather than all around it. There is a lot of uneven heating going on around the exhaust port area. The best power I know of was 62 horsepower out of an 850 cc engine as a sidevalve That's around 70 HP/Litre but at a lot of revs.

 

The Hudson Terraplane "Dome" engine was around 2.5 litres and 110 Horsepower in a car in standard form Not bad in 1938... Nev

 

 

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I'm interested only when a thousand aeroplanes have been flown for a thousand hours each behind these engines. Only then will we know what they're worth.

 

 

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Sick of sitting there waiting for something to happen eh D10? Oh ye of little faith. All engines blow up . It's just a matter of time. Nev

 

 

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Hmmm, a thousand engines at a thousand hours each , That's a million hours. Trouble free too, I suppose. Oh ye of little faith, you'll be waitng forever

 

 

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...........What IS needed is a around 100hp+ Diesel....Can't imagine in a region where they relish in their diesel cars.. why there are not more effective diesel aircraft motors coming out of Europe

Probably because in Europe we are limited to 450kgs MTOW. Diesels tend to come in too heavy.

 

As for the D-motor, the big attraction is that you can get 90+HP from an engine which weighs little more than a Rotax 582.

 

We have one of the original ones on a Sherwood Ranger at out club which is still on low hours, but once I hear some feedback from the owner, I'll post it here.

 

.

 

 

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berxbetter - lets all get cynical, sarcastic and generally nasty over this interesting and serious engineering endeavour. I think it might be helpful. Lets start by you showing us the aircraft-grade engine that *you* have designed, tested and built, eh?

 

I think its an interesting concept, and as an operator of the 1940 Continental A-65 currently in my Minicab I think its about time the redevelopment of the VW engines (Great Plains, Revmaster, Jabiru etc) was laid by the wayside. We really do need another lower revving engine with some genuine ingenuity (and torque!) behind it. Toothpick props and gear reductions are starting to get on my nerves - give me a sidevalve any day!

 

It looks to have a wonderfully flat torque and power curve, very nice indeed. I dare say the 6cyl version would be equally as impressive.

 

If you want to knock the Nikasil then you've got another thing coming. My first motorcycle was an Aprilia RS125 with Nikasil bore lining and made a legitimate 33hp from 125cc - that's about 264hp per litre. It revved out to 10,500rpm and didn't wake up til 7,500 or so, so most of its life was spent between those two numbers.

 

It got a staggering 12,400km out of its second piston during my ownership and had around 22,000km on it when I sold it. The bore lining was still mint condition. At an average of 70km/h that means it did over 300 hours at more than triple the max revs of an aircraft engine... making over 7 times the specific power! I doubt Nikasil linings will be any concern during the ownership of a new engine.

 

Reliability? Hell, you never know until something happens. At the moment we have Jabiru cylinder and valve problems and a Rotax crank AD. We'll see soon enough if there are D-Motor problems I guess. Until then I think they seem alright.

 

Cheers - boingk

 

 

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Thanks B 12 . There's plenty of others with tales to tell. Mine are fairly ordinary apart from the ones which would be looked at as being made up. We are in a different world from when I started. It's only about 107 years since powered flight was possible.. When people saw the DC3 in 1936 OTA they reckoned it would be too heavy to get off the ground. Nev

Wonder how far aviation would have progressed if so many of the knowlegable people in the industry were not so damned modest? Seems to be a not uncommon trait. I also wonder if if has something to do with there being "old pilot, bold pilot but not so many old bold pilots"?

 

 

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bexrbetter - lets all get cynical, sarcastic and generally nasty over this interesting and serious engineering endeavour.

Yeah, nah - just having a technical overview and debate. Apparently you missed where I said the engine's lighter weight and smaller frontal area may "have advantages".

 

Lets start by you showing us the aircraft-grade engine that *you* have designed, tested and built, eh?

Hmm the words "cynical, sarcastic and generally nasty" first came to mind reading that ... 006_laugh.gif.0f7b82c13a0ec29502c5fb56c616f069.gif

 

But anyway jokes aside, sure, in a few weeks the announcements will be made, just organising the company structure, land and factory these very days to produce *my* own unique bespoke to light aircraft 100hp engine. Designed by *me*, patented by *me*, tested by *me*, built by *me* and paid for by *me* - hope that helps, eh?

 

If you want to knock the Nikasil then you've got another thing coming.

Got my motorcycle mechanic ticket in the 70's in a Yamaha/Stihl dealership, have motorcycle engines that have powered bikes to Australian and Queensland titles in both road racing and motocross as recent as 5 years ago (all 2T). I've seen piles of 'effed' Nikasil barrels thrown in the rubbish bins out the back of dealers shops before some specialst shops started to find ways to repair them. I used to grab them out of the bins to cut them up to experiment with porting. Because you had a good run from one, as most do, doesn't change the facts of where one small mishap will leave you.

 

Besides all I refered to was the cost that will have to be born when a bore has a problem and I provided example of a business who all they do is repair Nikasil linings, a bit self explainatary isn't it? Ok, maybe not so I'll explain it - the shop is in business because there's lot of damaged Nikasil linings to be repaired, but that's for single individual barrels, have fun trying to get a matched set of DMotor cases repaired.

 

That you had a good run from an Italian bike is quite impressive by the way 006_laugh.gif.0f7b82c13a0ec29502c5fb56c616f069.gif

 

 

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Aprillia is a pretty good Italian bike.

 

Aero engines are a special circumstances engine. It's surprising how many of them have been quite bad over the years, and a lot of famous engines had quite short service lives untill the turbines came along and rewrote the reliability parameters.

 

The Merlins had some chronic faults (mag drive gears stripping and cam follower scuffing) to name a few and a low service life but the inherent strength of it allowed a lot of extra horsepower to be obtained, which served well in a military environment. It was not certifiable in most countries for civilian use.. AnRR Dart powered mustang was produced. Cavalier?.

 

Most piston engines were maintenance intensive and the final complex ones were no better for relability than the early 30's engines. Bypass jet engines have about 5 times the life of a good piston engine on average. Nev

 

 

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Well I got MY motorcycle "ticket" in the early sixties. I worked for Guzzi in Mandello for some time too. It was their work with chrome bores first that led to their patent (Niguisil). I have seen MANY,many bores with over 200,000 kms on them with very little wear. The only time wear was evident was when people took off the air filters. I saw lots and lots of rooted cylinders with nikasil bores but they were all two strokes ( Poor air filtration and ring problems) . And most of them were dirt bikes.......The bores are replatable quite easily and not as dear as a new Jabiru cylinder.............The bores on the D-Motor will be fine....

 

 

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Well I got MY motorcycle "ticket" in the early sixties. .

But have *you* designed an aircraft engine yet? - otherwise you're not allowed to comment in this thread 008_roflmao.gif.692a1fa1bc264885482c2a384583e343.gif

 

Hmm, seeing some of the responses I should mention that is humour.

 

Moto Guzzi ... It was their work with chrome bores first that led to their patent (Niguisil). .

You mean Mahle in Germany made Moto Guzzi motorcycles? Well I learn something new every day. 066_naughty.gif.fdb194956812c007d0f5d54e3c692757.gif

 

I have seen MANY,many bores with over 200,000 kms on them with very little wear..

Sadly so have I but now I do work that makes money instead.

 

The only time wear was evident was when people took off the air filters. .I saw lots and lots of rooted cylinders with nikasil bores but they were all two strokes ( Poor air filtration and ring problems) .

Oh, so you have seen some worn or damaged then. Not always people intentionally taking the air filters off either, sometimes not seated properly, sometimes well overdue for a service etc. - humans acting like humans. My point and my only point was the result of that is much more serious than a steel/iron liner under the same conditions, you seem to have missed that point, twice.

 

The bores are replatable quite easily ..

Shirley your not alluding that replating is as easy and as simply running a hone down a steel/iron liner?

 

Also you will have to send the cases away because there certainly ain't one around every corner and then you'll have to wait till they have enough to do a batch or you will pay a premium to have yours done individually.

 

...........The bores on the D-Motor will be fine....

Besides you not being able to prove that statement either way, I never said they wouldn't be.

 

Are we clear or do we meet behind the Mornington footy grandstand on Friday night to sort it out (harking back to my teenage days 006_laugh.gif.0f7b82c13a0ec29502c5fb56c616f069.gif ) - I grew up in Hampden St. (I see you're at Tyabb).

 

Don't take this too seriously guys, I'm not 002_wave.gif.62d5c7a07e46b2ae47f4cd2e61a0c301.gif

 

 

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You don't have much of an option with a sidevalve engine, such as this one. The Nikasil is the only way, unless you ran a high silicon alloy as the block metal and there the bore would be relatively soft. It's already been done in a lot of small Briggs and Stratton motors one small car in the US (Chev Vega??) where they had some quality control issues with the casting alloy uniformity. A pressed or cast in cylinder liner could be expected to give trouble in an alloy block in the region of the exhaust port due to the heat stress and distortion there,

 

"K" model BMW bikes have Nikasil treated block as do some of the 3.5 V8 Mercedes ( but the merc's are pretty cheap second hand because of this). I think they are usually refirbished by sleeving but I don't know how successfull it is.Other alloy blocks such as the BMC P76^ and the Landrover V8 are sleeved but the Rover engine has some sleeves come loose at times. These are all watercooled OHV engines, as distinct from Sidevalve ( also called L head or "flathead") Nev

 

 

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Shirley your not alluding that replating is as easy and as simply running a hone down a steel/iron liner?

Don't take this too seriously guys, I'm not 002_wave.gif.62d5c7a07e46b2ae47f4cd2e61a0c301.gif

God no and no worries, respectively!

 

I'm actually really interested in this engine now... sure seems more logical than a souped-up Briggs or a re-engineered VW to my mind anyway.

 

- boingk

 

 

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I'm actually really interested in this engine now... sure seems more logical than a souped-up Briggs or a re-engineered VW to my mind anyway.

I suggest you wait a few weeks then I'll show you something else to get excited about.

 

I am sitting here right now redoing some prior art for the 3rd time so the stupid Chinese patent company obviously can see what is non-obvious, which is obviously obvious to me obviously, but not obviously obvious to them obviously - obviously.

 

 

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I suggest you wait a few weeks then I'll show you something else to get excited about.

I am sitting here right now redoing some prior art for the 3rd time so the stupid Chinese patent company obviously can see what is non-obvious, which is obviously obvious to me obviously, but not obviously obvious to them obviously - obviously.

So will we be able to copy the Chinese version and make it less reliable? (just kidding..)

 

Seriously, looking forward to seeing the end result.

 

 

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Don't know if any of you have seen bexrbetter in disguise lately, but seriously, I was told by someone on a stand at the 2012 Oshkosh that Chinese business characters were going round trying to buy various items for cash on the spot - even complete engines. I imagine a bit of reverse engineering was planned using ultra high high quality Fosters tinnies?

 

 

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Here a couple of quotes, from someone who appears to know all about everything.................."You mean Mahle in Germany made Moto Guzzi motorcycles? Well I learn something new every day"

 

Nigusil is a patented metal alloy created by Moto Guzzi for motorcycle cylinder liners. The name is an acronym for Nickel-Guzzi-Silicon.

 

Moto Guzzi, having successfully created the first engine with a chromed cylinder lining, continued research to find a material that could replace chrome. The research culminated with Nigusil, a nickel-silicon alloy applied to the cylinder through special procedures. This innovation allowed lower friction coefficient in the engine, significantly lower levels of mechanical parts wear, and considerable savings of lubricant. Treatment of cylinders through Nigusil was also used by many manufacturers, Maserati among them, and generally on racing engines.

 

Here's another ............... "Shirley your not alluding that replating is as easy and as simply running a hone down a steel/iron liner?"............................. When a bore is damaged "running a hone through" will not cut the mustad.(type of hook , I know!) A rebore will.. Oh? you can't actually rebore some cylinders? You mean I have to buy new cylinders too? and pistons? 008_roflmao.gif.692a1fa1bc264885482c2a384583e343.gif Perhaps Nigusil or Nikasil might be a better choice? Ha ha

 

 

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