Pattakon engine.....legitimate alternative or just another fly-by-night

[revetec]

Very heavy pistons.

[santostripoli]

Half of the Pattakon's pre engine showing an 85mm bore piston made from 6061 Aluminium at 450g. The whole piston will be 900g. An equivalent piston from a conventional engine weighs about 300g.

Pattakon PRE piston is 200% heavier !!!

[revetec]

Even heavier....

[santostripoli]

How do you manufacture this groove? Typically camshafts (3) are ground and you cant do this.

You cannot machine it because the other lobe is in the way.

How do you adjust the valve clearances? You would have to ensure the valve seat and stem top did not wear over the whole life of the engine.

Tabs (1) and (2) are too weak.

[revetec]

Very valid points Santostripoli

[santostripoli]

It would be a real problem doing a valve adjustment on your x engine buddy oh pal

[revetec]

Originally Posted by manolis

The body of the pilot, just like the body of the rider on a bike, feels and responds and so “drives” the vehicle.

Thanks
Manolis Pattakos

You are not going to get all movements required for flying. How are you going to rotate around a verticle axis?
When you pitch the flying machine forward it will throw your body weight backwards. How are you going to hold it upright. Shifting body weight past a certain point wont work. You'll only be relying on body weight and gravity to keep it upright. tilt it too far and it will flip you over.

[revetec]

Originally Posted by manolis

Pattakon Pulling Piston Engine patent : US 6,062,187 (May 16, 2000)
(four years later Honda received the US 6,763,796 and US 6,763,796 patents on the same exactly subject)

Pattakon Cam Drive Mechanism (GRECO crankless engine)
PCT Patent Application : PCT/GR04/00052

Pattakon Pulling Rod Engine
1st Priority: GR20060100048
PCT Patent Application: PCT/EP2007/050809

In Japan, China etc Patent Offices more data can be found.

Thanks
Manolis Pattakos

Patents are so cool.

It doesn't have to work to patent a design, it just has to be different.

I wonder how much money is spent each year by people trying so hard to be successful, that it clouds their judgement of what will work and what wont?

Is it a lack of knowledge, or the lack of designing and analysis? Or do they hope to overcome problems at a later date?

I'm not having an opinion on anything specific in this thread, just ponding the question in general, and thinking out loud.

Oh yeah...Isn't it amazing that someone like Santostripoli who has just seen these designs and has no experience in the area of development of this engine can find the faults overlooked by experts working on the project. Good on you Santostripoli, you might have saved them money.

[revetec]

Pattakon website: Today everybody still asks "how much more power will this system make?".

Tomorrow the question could change to "OK, your engine makes great peak power, but beyond peak power what else it makes?"

So how much more power?

It is now 5 years since the Patent was lodged on a camshaft design. The engine tacho shows it goes to 9,000rpm, so the engine is running. How about posting a dyno graph which is third party certified to show us the improvements over the standard engine. If it is better I'm even interested.

[manolis]

I have to thank the whole Revetec team for their work on Pattakon’s projects.
The only that worries me if their findings are not the worst flaws of Pattakon’s projects.
Please continue the good work and the stress analysis.
There are more projects and engine versions to analyze in www.pattakon.com web site.

Thanks
Manolis Pattakos

[manolis]

Regarding the GRECO I3 (www.pattakon.com/greco/Grecoi3.exe ).
It is interesting that the initial simple design used to demonstrate the parts of the engine and their interrelation during motion, was near to be successful according their stress analysis! Compare the distance of the top and bottom rollers to the case of tri-lobe cams. Compare also the thrust loads.
I am not saying GRECO works, because Pattakon has not yet a GRECO prototype of this design.
But I hope that the tri-lobe design finally succeeds, then nothing can stop Pattakon GRECO.


Regarding the Pattakon PRE engine ( www.pattakon.com/pre ) , to make your analysis easier note that:
The first prototype (it is not yet finished) has the architecture of the www.pattakon.com/pre/PRE14.exe .
It has 81mm Bore, 50+50=100mm Stroke (i.e. two short stroke pistons create a long cylinder).
Two opposed pistons.
Two connecting rods (with 75mm center to center distance, i.e. 1.5 con-rod to stroke ratio).
The pistons are from aluminum except their combustion crowns / ring lands (steel).
Each crankshaft is a single piece and each connecting rod is a single piece (there is no mistake here).
The total weight of each “piston, piston pin and connecting rod assembly” is less than 1.4 Kg.
The lubrication is “four stroke” like. The oil rings never pass over the ports.
The cycle is compression ignition (Diesel).
No cylinder heads, i.e. less thermal loss during combustion.
The two built-in compressors (back sides of the pistons near piston pin), according Revetec’s law, aspirate efficiently (1.5 con-rod to stroke ratio).
At 6000 rpm, where the maximum power is expected ( www.pattakon.com/pre/droplet.exe ), the mean piston speed is 10 m/sec and the maximum acceleration is half of the maximum acceleration of the piston of a conventional with a 100mm Stroke and a 150mm center to center connecting rod (the mean piston speed in case of the “equivalent” conventional is 20m/sec).
The friction increases more than linearly with the mean piston speed, so a good reduction in friction is expected (think).
The mechanism provides some 30 to 40% more time at good conditions to the mixture to get prepared and burned efficiently (plots of PRE compared to conventional at www.pattakon.com/pre ). This reduces consumption and emissions.
Used in the Portable Flyer (www.pattakon.com/fly/Flyer4.exe and www.pattakon.com/fly/Flyer4.gif ) the opposed piston PRE is absolutely balanced (single cylinder) without any balancing shaft. It not only balanced as regards inertia forces and moments, it is also absolutely balanced as regards the combustion vibrations too (think).
The same engine can be used as airplane engine, either with one propeller or with two.
The same engine can be used with two counter-rotating electric generators for hybrid cars (no vibrations at all).
A way to increase this engine’s capacity is to use crankshafts with two crankpins at 180 degrees and two cylinders.


Regarding the control of the Portable Flyer.

Understanding how a rider of a bike (or of a bicycle) keeps the control of his vehicle’s speed and direction, no matter there are only two contact “points” with the road, is the first step to get the way the www.pattakon.com/fly/Flyer4.exe portable flyer is controlled by the pilot/rider. The drive by wire and the pitch control are unnecessary, heavy and expensive luxuries for a portable flyer (but they stay possible options).

Thanks
Manolis Pattakos

[Matra et Alpine]

Is it just me or does it look as if Manolis idea is that by asking questions he finally frustrates real engineers to do the necessary work on the Pattakon engine for free ?

Re the cam construction sans .... the lobes can be machined off the camshaft and then fitted by interference fit. BMW have done this on their motorbikes for years. Not a great fan of it tho for obvious reasons. But the rest of it looks so weak I don't see it being able to control the momentum of the valve. Compare it with the strength in the design and material used in the most successful desmodronic valve system.

[lightweight]

Here are the pics I promised. They come from "R&D Team" Magazine, Issue 3, published in June 2003. The author is Dionisis Hoidas (dihoidas@otenet.gr)

[revetec]

Originally Posted by manolis

Regarding the GRECO I3 (www.pattakon.com/greco/Grecoi3.exe ).
It is interesting that the initial simple design used to demonstrate the parts of the engine and their interrelation during motion, was near to be successful according their stress analysis! Compare the distance of the top and bottom rollers to the case of tri-lobe cams. Compare also the thrust loads.
I am not saying GRECO works, because Pattakon has not yet a GRECO prototype of this design.
But I hope that the tri-lobe design finally succeeds, then nothing can stop Pattakon GRECO.

The problem is manolis that on a multi cylinder Greco engine, with those cams of yours on that shaft, if it was made one piece it would be very hard to manufacture. Grinding the internal radius of the cams would require a grinding machine with a 90 degree drive and a very small grinding wheel to do the job. A small grinding wheel so small will wear at a rate that it would be near impossible to guarantee the acuracy in production. The alternative would be to make the shaft in at least 3-6 sections and dowl pin it together. The parts required to be made provides only a section of about 3 square centimeters for two dowls and two bolts (which there is no room to bolt it) and then it would be near impossible to get it and keep it all straight. I've looked at it in depth and it is not viable for production, even if you could make it strong enough.

Originally Posted by manolis

Regarding the Pattakon PRE engine ( www.pattakon.com/pre ) , to make your analysis easier note that:
The first prototype (it is not yet finished) has the architecture of the www.pattakon.com/pre/PRE14.exe .
It has 81mm Bore, 50+50=100mm Stroke (i.e. two short stroke pistons create a long cylinder).
Two opposed pistons.
Two connecting rods (with 75mm center to center distance, i.e. 1.5 con-rod to stroke ratio).
The pistons are from aluminum except their combustion crowns / ring lands (steel).
Each crankshaft is a single piece and each connecting rod is a single piece (there is no mistake here).
The total weight of each “piston, piston pin and connecting rod assembly” is less than 1.4 Kg.

So that's 1.4kg + 1.4kg totaling 2.8kg for two pistons equivalent to a 80mm piston with a 100mm stroke being 250cc.

I just physically weighed a piston an rod assembly from a cylinder of a 250cc engine. The total weight of the piston and rod was 1.1kg. Until Pattakon can prove that they can get both piston assemblies around a total of 1.1kg, it wont be able to perform against a conventional engine.

Originally Posted by manolis

Regarding the control of the Portable Flyer.

Understanding how a rider of a bike (or of a bicycle) keeps the control of his vehicle’s speed and direction, no matter there are only two contact “points” with the road, is the first step to get the way the www.pattakon.com/fly/Flyer4.exe portable flyer is controlled by the pilot/rider. The drive by wire and the pitch control are unnecessary, heavy and expensive luxuries for a portable flyer (but they stay possible options).

Thanks
Manolis Pattakos

Your understanding of what it takes to maneuver such a machine is very limited. The picture you posted also has a mechanism for variable pitching the blades (Like a standard helicopter) to control all movements. Look....you might find some way to get the weight down and make the PRE engine work, whether it will be efficient is another story, but the flying machine idea posted on the pattakon website may as well been drawn by a kid because it lacks an designs of controls required for it to fly. Let's get any engine and gear two propellers to it and call it a flying machine...eh?

[revetec]

Originally Posted by Matra et Alpine

Re the cam construction sans .... the lobes can be machined off the camshaft and then fitted by interference fit. BMW have done this on their motorbikes for years. Not a great fan of it tho for obvious reasons. But the rest of it looks so weak I don't see it being able to control the momentum of the valve. Compare it with the strength in the design and material used in the most successful desmodronic valve system.

Think about this though...You have to press the camshaft lobes on while installing those tabs between. The biggest problem is valve clearance. Valves settle into seats, the tops of valve stems wear, there are manufacturing tolerance differences. This is why we have valve adjustments or shim adjustments that are made at the factory and in the service life of an engine. And if a valve burns out or doesn't seal, when repairs are carried out, how are the valve adjustments going to be done?