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Bourke engine viability?

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Cass256

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If you're not familiar with this type of engine, here's an article and here's everything else you could want to know.
What are your guys thoughts on this type of engine?

I think the idea of using detonation for power is genius, and if the claimed performance specs are anywhere near true (weighed 38lbs, 30cu in. making 76hp at 10k rpm, burns 1gal/hr at 6500rpm ) it could be revolutionary not only for aviation, but the motor industry as a whole.

Would it be worth it to pursue designing a one-off of this design? As far as I can tell, the problem everyone's run into with the engine is fuel delivery. A standard carb just doesn't work, and the original #001 engine ran with a constant velocity carb. I think this would be a great candidate for FADEC, though I'm not confident I could pull that off myself. It supposedly runs very lean, giving it great efficiency. Burning less gas would be a major benefit in my plane, since I can only hold 10 gal.

If I were to pursue making one for my plane, do you guys have any suggestions for parts manufacturers/mechanical engineers that could help?
 

Marc Zeitlin

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If you're not familiar with this type of engine, here's an article and here's everything else you could want to know.
What are your guys thoughts on this type of engine?
I am as far from an internal combustion engine expert as one could get, but this:


seems to present enough verified information to at least cast substantial doubt on both the power and efficiency claims for this engine. Given that it's gone exactly nowhere in 100 years, I'm going to hazard a guess that the doubts are well founded.
 

Toobuilder

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My dad was one of the Bourke "zealots" and spoke often about building one of the engines for a homebuilt. Even back then, as a kid, I was cynical enough to wonder why these were not in use if they were so great? 45 years later, in the face of incredible performance claims - yet no examples running, my cynycism remains unabated.

With the prototype tooling and engine management capability we have today, it would be relatively easy to crank one of these out - so why isn't the market yet flooded with them? Quick, someone whip up a slick CGI presentation and get some investors roped in!
 
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Topaz

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If you're not familiar with this type of engine, here's an article and here's everything else you could want to know.
What are your guys thoughts on this type of engine?

I think the idea of using detonation for power is genius, and if the claimed performance specs are anywhere near true (weighed 38lbs, 30cu in. making 76hp at 10k rpm, burns 1gal/hr at 6500rpm ) it could be revolutionary not only for aviation, but the motor industry as a whole.

Would it be worth it to pursue designing a one-off of this design? As far as I can tell, the problem everyone's run into with the engine is fuel delivery. A standard carb just doesn't work, and the original #001 engine ran with a constant velocity carb. I think this would be a great candidate for FADEC, though I'm not confident I could pull that off myself. It supposedly runs very lean, giving it great efficiency. Burning less gas would be a major benefit in my plane, since I can only hold 10 gal.

If I were to pursue making one for my plane, do you guys have any suggestions for parts manufacturers/mechanical engineers that could help?
Answering perhaps a little more seriously, the issue here isn't "making one for your plane." The issue is really "making one at all." Taking this from the concept stage where it's been for decades to even a reliable, reasonably running "bench" motor is going to be a major development project in its own right. You're not going to be able to just bolt together some off-the-shelf parts from other engine designs and create a working engine that you then bolt onto your airplane.

If engine development suits you of its own accord, then learn everything you can about designing engines - from scratch - and prepare yourself for a new journey lasting possibly decades. If that appeals to you, then carry on!

If you're just looking for a "better engine for your plane," then this isn't the route you want to take. Far better to thoroughly review the existing offerings and choose the best choice from among them.

Out of curiosity, what airplane do you have/are working upon?
 

wsimpso1

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Hmmph. So many issues. Essentially this is a two stroke opposed cylinder diesel. They can be quite fuel efficient when operated on the fuel island. Detroit Diesel made them for decades and huge ones are used for ship powerplants.

Now to issues:

Scotch Yoke does reduce piston thrust loads and friction, and resolves higher order imbalance, but brings immense reciprocating loads and imbalance, is tough to make durable, and then you still get offset loads on the rod bearings and seals. In short, the trade is better with a conventional crank and rod system;

Induction pumping using the bottom of the piston in a chamber precludes oil jet cooling of the piston crown and lubing the piston skirts, both of which limit power to modest levels;

Fuel is delivered to the intake port during combustion chamber fill and auto-ignition gives firing? Ugh. Modern available common rail injection is used in diesels and you can tune the injection pulses to optimize for power or efficiency.

If you want fuel efficient light weight diesels, go look at Deltahawk and Gemini. They each have neat looking products, are further along than the Bourke, without its drawbacks, and can not seem to launch...

But start building one at home?
Billski
 

Cass256

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Answering perhaps a little more seriously, the issue here isn't "making one for your plane." The issue is really "making one at all." Taking this from the concept stage where it's been for decades to even a reliable, reasonably running "bench" motor is going to be a major development project in its own right. You're not going to be able to just bolt together some off-the-shelf parts from other engine designs and create a working engine that you then bolt onto your airplane.

If engine development suits you of its own accord, then learn everything you can about designing engines - from scratch - and prepare yourself for a new journey lasting possibly decades. If that appeals to you, then carry on!

If you're just looking for a "better engine for your plane," then this isn't the route you want to take. Far better to thoroughly review the existing offerings and choose the best choice from among them.

Out of curiosity, what airplane do you have/are working upon?
Yeah you're right, the issue of making one at all I suppose is really what I'm trying to tackle. There are a few running prototypes out there, but as wsimpso1 pointed out, the yoke crank is the weak point of the current design. Rehashing this design won't solve it's problems, either.

In terms of "a better engine for my plane", currently I have a Ridge Runner model 3 that I'm restoring with a Rotax 503 on the front. The 503 has its own problems, but the power to weight is unparalleled in this weight class (The planes' MTOW is 950lbs, est. empty is 350-450). The other options of higher HP motors for this plane are the 582, HKS, Jabiru, and VW; However all of them have significant power to weight tradeoffs comparatively. The HKS weighs close to 180lbs for 60hp, compared to the <80lbs for 50hp of the 503 (both installed & wet weight).

The Bourke concept of using detonation is really what interests me, and I might pursue using this in a different application than the Scottish yoke crank. If detonation really is a more efficient way to combust fuel, I think it's worth investigating. I have other plane designs I'd love to build, but having a motor that rivals the power to weight of a 503 in a larger application is necessary.

I am interested in designing an engine from scratch, not necessarily using off the shelf parts, and I know this is no small task/journey. Do you have any advice where I could start with this? Should I go get a mechanical engineering degree? Should I try to find other people who might be interested in working for me designing this? I'd like to create an RC scale version for bench testing, using CNC milled parts or something similar.
 

Topaz

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I really can't speak to what you should do to start designing engines. Not at all my area of expertise. A formal education in mechanical engineering certainly seems like a good thing; finding other people who share your interest seems like a must-have, and they might be able to help you find the right path.
 

Curt Curtis

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Put bourke engine on the internet, you should get lots of info.
there are several groups and clubs involved. bourke has a book
about his engine. One guy is selling the book and info as business.
CURT
 

Traskel

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The simpler version axial engine (nearly) brought to fruition by Dynacam would be easier to develop. Sold to Aero Marine who I guess managed to complicate the design they eventually produced on for a generator.

I met Dennis Palmer of Dynacam and got a tour of his facility and a detailed introduction to the design. I believe the help of any brilliant IC designer / tuners from the automotive racing industry could have refined his design quickly into one of the greatest GA engines ever made.

Unfortunately that didn't happen. Perhaps Liquid Piston? MYT?
 

Victor Bravo

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My dad was one of the Bourke "zealots" and spoke often about building one of the engines for a homebuilt. Even back then, as a kid, I was cynical enough to wonder why these were not in use if they were so great? 45 years later, in the face of incredible performance claims - yet no examples running, my cynycism remains unabated.

With the prototype tooling and engine management capability we have today, it would be relatively easy to crank one of these out - so why isn't the market yet flooded with them? Quick, someone whip up a slick CGI presentation and get some investors roped in!
I'll volunteer to provide the literary fertilizer to entice the website readers, in exchange for a .0001% share in the net net net profit
 
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blane.c

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I have a metal shaper built at the turn of the century (about 1898 plus or minus) It has a Scotch yoke. I cannot imagine however amazing, that contraption as a focal point of power transmission in an aircraft. But it is amusing to watch it in action.

The free piston design part of the engine minus the Scotch yoke is interesting as magnets could be housed between the pistons instead of all that contraption, the magnets passing through copper or aluminum wire windings could produce electricity to run a hybrid. I imagine it would take several sets of pistons to "dampen" electric pulse?
 

Sockmonkey

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My dad was one of the Bourke "zealots" and spoke often about building one of the engines for a homebuilt. Even back then, as a kid, I was cynical enough to wonder why these were not in use if they were so great? 45 years later, in the face of incredible performance claims - yet no examples running, my cynycism remains unabated.

With the prototype tooling and engine management capability we have today, it would be relatively easy to crank one of these out - so why isn't the market yet flooded with them? Quick, someone whip up a slick CGI presentation and get some investors roped in!
I've seen a guy on youtube doing a test run of his bourke. That sucker sounded ANGRY, but it ran quite well as far as I could see. As Topaz has pointed out here and other places, You also have to be a good businessman to set up production of a new engine, which has tons of overhead costs just to break even.
Getting someone else to produce it under license means convincing them it will sell enough to offset things like retooling costs, and fighting institutional inertia. Plus they may not accept any deal that doesn't give them full control over the design so they can eventually freeze you out.

There are other crank options like this.
Hmmph. So many issues. Essentially this is a two stroke opposed cylinder diesel. They can be quite fuel efficient when operated on the fuel island. Detroit Diesel made them for decades and huge ones are used for ship powerplants.

Now to issues:

Scotch Yoke does reduce piston thrust loads and friction, and resolves higher order imbalance, but brings immense reciprocating loads and imbalance, is tough to make durable, and then you still get offset loads on the rod bearings and seals. In short, the trade is better with a conventional crank and rod system;

Induction pumping using the bottom of the piston in a chamber precludes oil jet cooling of the piston crown and lubing the piston skirts, both of which limit power to modest levels;

Fuel is delivered to the intake port during combustion chamber fill and auto-ignition gives firing? Ugh. Modern available common rail injection is used in diesels and you can tune the injection pulses to optimize for power or efficiency.

If you want fuel efficient light weight diesels, go look at Deltahawk and Gemini. They each have neat looking products, are further along than the Bourke, without its drawbacks, and can not seem to launch...

But start building one at home?
Billski
I solved the oil issue in my own design which also uses the underside of the piston to pump in the fresh charge. The crosshead piston rod has tunnels running up it to the piston which has a set of radial tunnels from the center to the rim between the rings. It uses intake ports rather than valves which will result in some oil loss but not enough to be a deal-breaker as 2-stroke diesels use a similar system without issue.
Here's a 3 cylinder version.

There would be crosshead guides and valves in the cylinder heads which are not shown here.
 

wsimpso1

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I've seen a guy on youtube doing a test run of his bourke. That sucker sounded ANGRY, but it ran quite well as far as I could see. As Topaz has pointed out here and other places, You also have to be a good businessman to set up production of a new engine, which has tons of overhead costs just to break even.
Getting someone else to produce it under license means convincing them it will sell enough to offset things like retooling costs, and fighting institutional inertia. Plus they may not accept any deal that doesn't give them full control over the design so they can eventually freeze you out.

There are other crank options like this.

I solved the oil issue in my own design which also uses the underside of the piston to pump in the fresh charge. The crosshead piston rod has tunnels running up it to the piston which has a set of radial tunnels from the center to the rim between the rings. It uses intake ports rather than valves which will result in some oil loss but not enough to be a deal-breaker as 2-stroke diesels use a similar system without issue.
Here's a 3 cylinder version.

There would be crosshead guides and valves in the cylinder heads which are not shown here.
This is the same pumping scheme as is shown in Post 1 of this thread. The chamber below the piston is the pumping chamber, which still precludes tossing oil at the underside of the piston crown to allow higher specific outputs. The pumping chamber below the pistons allows combustion chamber fills approaching 100%, but running a blower can assure full exhaust and allow some supercharging while allowing the engine itself to be quite a bit more compact.

The two stroke diesels I know about all use a positive displacement blower (Roots type superchargers are usually used) for starting and low to medium power, then a turbocharger comes up to speed for higher power operations. The blower and turbocharger are plumbed in series. Some use port timing for inlet and exhaust, others port time the inlet only and have poppet valves for exhaust. The most fuel efficient engines we know off are this scheme, used in ships.

Billski
 

blane.c

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They also use "Bunker fuel" a kind of "tar" that is heated up before it can flow whether to be pumped on to the ship or to be consumed in the engine, it has a higher BTU than diesels that flow at lower temperatures and that higher BTU contributes mightily to the engines fuel efficiency.
 

pictsidhe

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If you are going to build a 2 stroke radial, an even number of cylinders gives better balance. Can't do that on 4 strokes without uneven fire.
 

Sockmonkey

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The chamber below the piston is the pumping chamber, which still precludes tossing oil at the underside of the piston crown to allow higher specific outputs.
Right, that's why I have the oil flow inside the piston and crosshead rod to get to the rings.
 
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