Totally new type of IC engine.

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Appowner

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Yes apparently so...I once bought a whole model shop when it closed up...I have lotsa stuff there.
The RCV engines had cooling issues. Novel idea but..................

I'd be interested in hearing what other RC model engines you might have and if any are for sale. I have a modest collection and am always on the lookout for something new.
 

Blackhawk

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I don't know if you realise but the gears also are a 2:1 reduction drive so there's no need for a gearbox fo be added.

Here's a scaled down 26cc version of the MA-250

Mi-8 26cc b.jpg

And a concept of a triple 500cc (1.5L) engine which has clutches on each drive shaft making it possible to isolate one or two of the engines for cruise effeciency or malfunctions

Mi-8 Triple.jpg
This is an engine with amazing possabilities for the aviation industry and I am sure the inventor knows exatly what he is doing
 

jedi

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I am looking for more discussion on the rotary valve shown in the video. That appears to be the weak spot. It has limited area and needs a good seal. Does it need lubrication? Of course the rotary valve could be replaced with popet valves but then you are back to prior configurations. Thoughts?

I see a lot of RR discussions coming.
 

wsimpso1

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Hi,



It's certainly a very cute engine. Basically, it's a rotary valve engine which spins the cylinder around its own axis so it can use an integral cylinder with a valve-opening instead an "open-topped" one only closed by the rotary valve.

Generally, rotary, rotary valve and sleeve valve engines haven't fared so well with regard to emission control, because it's difficult to tailor the charge/discharge control.

But I'm not an expert ... it'll be interesting to see what this engine type will be used for.

Regards,

Henning (HoHun)
It also is a built-in speed reducer by the ratio of the fixed to crank mounted gears. This does allow running a piston fast and a output shaft slower or faster...
 

wsimpso1

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Arrange them radially, geared around a central shaft? I’m not a big believer that this engine is here to save us but surely there are ways to daisy chain them together.
Lots more gears and shafts that have to stand the firing pulses. That will be "stiff system", meaning heavy.

The big issue with the base design is all of the gears must be stout enough to drive first resonant order above firing frequency while also having very low to zero lash so that the firing speed oscillation does not make big impact on the gear teeth.

Now assemble more than one of them to a common shaft, and the gear(s) and shaft(s) must all carry the firing pulses, and either put the lowest resonant frequency above that combined firing frequency (another "stiff" system) or make it a "soft" system where a combination of enough inertia on the firing side is combined with low enough spring rates to put system resonance below idle firing frequency.

I suspect much or all of its weight advantage will be gone by making the it into a multi-cylinder engine.

Billski
 
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wsimpso1

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I think it looks very neat packace.

Don't forget Hughes had 8 engines on H-4.

Jerries had 6 on one design.
Distributed power does look like its best scheme. Then you will also need as many starters as engines, and singles need big starters relative to their weight...
 
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BJC

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I am sure the inventor knows exatly what he is doing

That is good to know.

Who is he, what is his background, and what has he previously accomplished?

You would be better to contact Avardi and get the information you require straight from the source.
Is the statement above your response to my question?

The information that I was seeking is your basis for asserting that “the inventor knows exatly what he is doing”.

Thanks,


BJC
 

wsimpso1

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I don't know if you realise but the gears also are a 2:1 reduction drive so there's no need for a gearbox fo be added.

Here's a scaled down 26cc version of the MA-250

View attachment 132109

And a concept of a triple 500cc (1.5L) engine which has clutches on each drive shaft making it possible to isolate one or two of the engines for cruise effeciency or malfunctions

View attachment 132110
This is an engine with amazing possabilities for the aviation industry and I am sure the inventor knows exatly what he is doing
I look forward to seeing what it weighs, costs, power and fuel burn, and durability, all demonstrated by testing.

I suspect that by the time it is durable, its weight advantage is lost. I also worry that cooling at the head end of the engine will be seriously hindered by the rotary valve system... making it cool adequately can be a real challenge.
 

HoHun

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Hi,

It also is a built-in speed reducer by the ratio of the fixed to crank mounted gears. This does allow running a piston fast and a output shaft slower or faster...

Isn't the gear ratio determined by the requirement to position the port for intake/exhaust in sync with the piston strokes?

Regards,

Henning (HoHun)
 

Jay Kempf

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Arrange them radially, geared around a central shaft? I’m not a big believer that this engine is here to save us but surely there are ways to daisy chain them together.
This is what I have seen from a company in Quebec. Fore and aft pointing cylinders around a central shaft. Seems like the same engine.
 

wsimpso1

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I don't know if you realise but the gears also are a 2:1 reduction drive so there's no need for a gearbox fo be added.

The integral gear drive can have any ratio one would want base upon need. 2:1 is not a requirement of the engine concept. Even ratios are usually a bad idea too... Most likely both gears should have numbers of teeth in prime numbers to keep vibe and wear issues at bay.

And a concept of a triple 500cc (1.5L) engine which has clutches on each drive shaft making it possible to isolate one or two of the engines for cruise effeciency or malfunctions

View attachment 132110
This is an engine with amazing possabilities for the aviation industry and I am sure the inventor knows exatly what he is doing
The clutches and additional gearsets and additional shafts all add weight and vibrational issues that all must be managed. And we still have to get induction and exhaust around the thing and figure out how to cool the head end of the engine adequately. The weight advantages are going away...

Current engine is what, 10 hp? We need on the order of 100 to 200 hp to talk about most of the homebuilt airplane market. If you get 20 HP out of a single, you can fly Part 103 or the Quickie. But 100-200 hp is 10 to 20 of these engines.

I suppose we could distribute them along the leading and trailing edges of the wing and tail. Now that drives an entire new airplane design around one engine type. Sounding more and more unworkable as well.

As to the inventer knowing what he is doing, I will wait and see on that too.

Billski
 
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wsimpso1

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This is what I have seen from a company in Quebec. Fore and aft pointing cylinders around a central shaft. Seems like the same engine.
Got a website or pictures we can look at?

Let's see if I can describe what you say. We take two of these engines, rig one to rotate opposite direction from the other, mount their output shafts together making a long engine with a central power takeoff, then hang a parallel shaft gear set between them to get power out? I can see how that might work. Time them to run pistons moving opposite each other, stagger the firing pulses so it has one pulse per turn instead of one pulse per two turns. We are still using up the weight advantage that I am still not sure exists in the first place, but at least the axial vibe is greatly reduced and the rotational vibe is improved. We still have to add some stuff to it and make it all behave vibrationally and turn a prop without shedding blades.

This is doubling the engine size. We have 10 hp, and need a couple hundred or more. For doubling the engine to work, we would still need a 5x to 10x power increase per cylinder. When we enlarge piston stroke, we usually have to reduce max rpm to keep piston speeds within bounds, which reduces the power per unit displacement, so displacement has to go up still more. The really big two stroke diesels used in big marine vessels run at only a couple hundred rpm for a reason.

Billski
 
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jedi

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Got a website or pictures we can look at?

Let's see if I can describe what you say. We take two of these engines, rig one to rotate opposite direction from the other, mount their output shafts together making a long engine with a central power takeoff, then hang a parallel shaft gear set between them to get power out? I can see how that might work. Time them to run pistons moving opposite each other, stagger the firing pulses so it has one pulse per turn instead of one pulse per two turns. We are still using up the weight advantage that I am still not sure exists in the first place, but at least the axial vibe is greatly reduced and the rotational vibe is improved. We still have to add some stuff to it and make it all behave vibrationally and turn a prop without shedding blades.

This is doubling the engine size. We have 10 hp, and need a couple hundred or more. For doubling the engine to work, we would still need a 5x to 10x power increase per cylinder. When we enlarge piston stroke, we usually have to reduce max rpm to keep piston speeds within bounds, which reduces the power per unit displacement, so displacement has to go up still more. The really big two stroke diesels used in big marine vessels run at a couple hundred rpm for a reason.

Billski
“ stagger the firing pulses so it has one pulse per turn instead of one pulse per two turns.”

Is it one pulse per two turns or two pulses per one turn?

Multiple cylinders should be head to head or back to back to balance longitudinal vibrations. Multiple cylinders or pairs of cylinders around a central shaft can have non intigral gear ratios but the crank bevel gear ratio needs to be an integer. IMHO.
 

Tiger Tim

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The integral gear drive can have any ratio one would want base upon need. 2:1 is not a requirement of the engine concept. Even ratios are usually a bad idea too...
These single cylinder, four stroke rotary sleeve valve engines are geared 2:1 with purpose, the same reason the cam shaft on a piston engine is geared 2:1. They just tap the output off the valve timing gear instead of the crank shaft.

Continental did the same thing with their Tiara series engines without great results.
 

wsimpso1

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“ stagger the firing pulses so it has one pulse per turn instead of one pulse per two turns.”

Is it one pulse per two turns or two pulses per one turn?
I am speaking of pulses per crankshaft rotation. A single gets one firing pulse per two rotations of the crankshaft. If you have two pistons running out together/ in together, the engine is then completely balanced. There will be no imbalance in any linear axis.

With it rigged as an opposed twin, I would time induction-firing-exhaust to alternate between sides of the engine giving an even firing engine.

There are several reasons to talk in terms of crankshaft rotation. The first is that this what the crankshaft, piston, induction and exhaust valving, and ignition all run at. Firing pulse torsional vibration also runs relative to that speed.

As to the ratio with output speed - you can make the ratio between crankshaft speed and output shaft speed suit whatever prop rpm you want. Yes output shaft at one-half of crankshaft speed is convenient for packaging, but if we scale up the piston diameter and stroke very much, we might need a lower reduction to get both appropriate piston speed and appropriate propellor speed. And there is no functional reason why we can not.
Multiple cylinders should be head to head or back to back to balance longitudinal vibrations.

Agreed.
Multiple cylinders or pairs of cylinders around a central shaft can have non intigral gear ratios but the crank bevel gear ratio needs to be an integer. IMHO.
Why so? If we are concerned about induction/ ignition/ exhaust timing, the drive between output shaft and valve shaft can include the right gear ratio for any primary ratio and still be perfect. Put our EFII timing magnets on the same shaft as the induction/ exhaust valve, and it all times up.

Billski
 
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wsimpso1

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Do you believe what they say about the torque ?
At the crankshaft, normally aspirated gasoline piston engines at sea level make maximum torque of about 1 foot-pound per cubic inch displacement. There Is a max torque point on any engine, with lower torque both at higher and lower rpm than at peak. Boost them, and torque roughly scales with the ratio of manifold pressure to sea level ambient pressure.

To make power, which makes airplanes climb and go fast, you take torque times rotation speed. Rigorously, ft-lb times rpm/5252 to get horsepower. The higher the rpm where it makes good torque, the more power.

The prototype runs a 2:1 reduction, so whatever torque is being made at the crankshaft is doubled at the output shaft while rpm is halved. Well, minus about 1% for gear losses. Torque went up, rpm went down, power is the same minus the 1% losses in the gear set. Torque does not go up exponentially, but is doubled.

Billski
 
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wsimpso1

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I just figured out that the cylinder turns with the carrier for the gear set, which kind of ties them to a 2:1. Again no magic in that, a second smaller gear set can drive the cylinder at the right speed if scaling demands a different reduction gear.

If instead we have other gearing in the combiner, then the same basic 2:1 can be used in primary gear set. Either way it can use.
 
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