2 stroke thread (with occasional F1 relevance!)

[uniflow]

Why don't they melt pistons? Must bypass a lot of fuel for internal cooling.

[J.A.W.]

I guess the upstream/draw through carb compensates?

There are turbo kits for current DFI snowmobiles..
..but maybe they are primarily for mountain altitude compensation - rather than max output pumps..

[fredric21]

I am building a sleeve-valve, opposed piston two-stroke diesel engine which is currently undergoing motoring tests. It all looks very promising at the moment. I am using a bore of 70 mm and stroke of 32 mm for a 125 cc displacement for each piston and it uses four pistons in two cylinders. Blow down occurs at BDC and scavenging (also at BDC), 20 degrees crank rotation later.
Supercharge occurs after 120 degrees of scavenge and lasts for 20 degrees. Port areas are equal to one piston area.
The engine has a dry sump and is supercharged and turbocharged. Friction horsepower is only 1.0 at 10,000rpm.

Because of patents, I cannot discuss further details at the moment. The sleeves have no ports, therefore no oil is dragged into the exhaust. The engine utilises direct injection after closing of the transfers. I anticipate high BMEP's.

[uniflow]

Well, that's no good. we need to see how it works.

[J.A.W.]

Well, that's no good. we need to see how it works.

Agreed, no teasing, if you please, F21..

You must have the programmed out-put projections..
..whilst in-the-metal tests will give proof of concept, you surely have the confidence to put a bit more up ?
Here & now..

[manolis]

Hello.

In the gif animation below, they are shown the internals of a different two-stroke (among others, the cooperation of the connecting rod with the piston and the casing offers asymmetric transfer and intake).



A guy having the PatATi Portable Flyer secured on his shoulders could fly above the Formula 1 circuit looking / recording the race.





The PatATi Portable Flyer looks like a scale-down of the Osprey (Bell Boeing V22), above.


For more:
http://www.pattakon.com/pattakonFly.htm
and
http://www.pattakon.com/pattakonPatAT.htm

Thanks
Manolis Pattakos

[autogyro]

We currently have a number of Boeing Osprey flying over our heads here in Norfolk UK.
In the 1960s 70s, the concept of tilt wing helicopter flight was discarded by the UK aviation industry as far to dangerous.
The Osprey has already killed a number of crews and passengers.
I am not happy the things are flying over my grandchildren.
Anyone who supports this flight concept should take the trouble to list the number of potential parts failures that will result in a catastrophic crash.
The Fairey Rotodyne was a far superior concept and infinitely safer.

[manolis]

Hello Autogyro.

You write:
"In the 1960s 70s, the concept of tilt wing helicopter flight was discarded by the UK aviation industry as far to dangerous."


Quote from the Internet ( http://aviationweek.com/defense/v-22-co ... ction-rate# ) about the Osprey V22 cost and sales:

The average price in fiscal 2012 was $67 million; the target price for the next multiyear is $70 million

Israel is likely to be the first foreign customer to take delivery of a V-22, and the United Arab Emirates the second. Japan is also possibly a near-term buyer as well. Last week, the Japanese conducted trials in which V-22s landed on their Hyuga and Shimokita class ships and were stowed in the belly of the Hyuga-class ship.

The cost per flying hour of the V-22 has decreased by 19% over time to $9,250.

To date, 214 MV-22s have been delivered to the Marine Corps. Three of 12 planned for use as executive airlift in the Washington region have been delivered to the Marines.

The service plans to buy 360 MV-22s. The Air Force wants 50 CV-22s and the Navy still holds a requirement for 48 V-22s to be used as a C-2 Greyhound replacement for the Carrier Onboard Delivery requirement."

End of quote.


The tilt-rotor Osprey V22 costs more than $70 million.
Several countries are waiting to pay for it.

It seems in 1960s 70s the UK aviation was wrong in their forecast / estimation.

Thanks
Manolis Pattakos

[autogyro]

They said the same about the Chinook and I refuse to fly in that as well.
Another ancient concept based on the Bristol Belvedere.
Complex gearing and the reliance on powered rotors to remain aloft result in an inability to autorotate under 500ft.
The results of almost any mechanical failure are fatal.
No ifs or buts fatal.

http://en.wikipedia.org/wiki/Accidents_ ... -22_Osprey

Check out the 'British' Fairey Rotodyne that the Americans forced us to scrap.
A far superior aviation concept that was much safer, a modern version would have a far better performance than the Osprey.
The Rotodyne had NO complex gearing and was safe at any height.
A modern version would replace the C130, the Chinook and make a next generation gunship.

Same with that dog the Lockheed F35, already over five years obsolete and inferior in simulations to anything out there it will meet in combat and it STILL doesnt work.
We are now stuck with two through deck carriers with no catapults, no angled flight decks that will only be able to operate helicopters.
So dont sing the praises of the Osprey it is a death machine.
I am just surprised that Rolls Royce make the engines for the Osprey, they refused to make engines for the F35 because the front turbine was designed to drive the forward lift fan which limits the engine to just nine vertical take offs before a complete rebuild, a dog of an aircraft.

American aviation is still 50 years out of date.
It stopped developing when they ran out of WW2 German and British stolen ideas.
Using such ideas from over 50 years ago for VTOL and modernising them simply does not work properly.
As has often been said, 'You can make a brick sh-- house fly if you give it enough thrust', that will not give you a new aviation concept.

[Tommy Cookers]

Check out the 'British' Fairey Rotodyne that the Americans forced us to scrap.

Same with that dog the Lockheed F35, already over five years obsolete and inferior in simulations to anything out there it will meet in combat and it STILL doesnt work.
We are now stuck with two through deck carriers with no catapults, no angled flight decks that will only be able to operate helicopters.

the Rotodyne was scrapped because Napier failed to produce a suitable engine
so the rotor had to be driven by tip ramjets that were about 20 dB noisier than the intended rotor drive
most of the orders for the Rotodyne were American

the last proper UK carrier schemed before the 'carrier ban' (the 422 ?) had anyway abandoned the angled flight deck
yes, since the Harrier really came to exist only because the RN needed it to bypass the ban on carriers ......
subsequent events have been bizarre, the USAF even ordering the stovl F35 versions to force their survival
so acting against the USNs scope to whittle away the position of its USMC
and the UK now has 2 full-size carriers to be equipped with aircraft intended for under-size carriers ?

remember though, any version of the F35 is an order of magnitude stealthier than alternatives eg navalised Typhoon or even Rafale

[Richard]

Please can we get back on topic? That's the potential for 2 stroke engines in F1 by the way.

[manolis]

Hello Richard.

While for most people “flying above the Formula 1 circuit looking / recording the race” would be way more interesting than participating in the Formula 1 race,
some versions / arrangements of the PatATi (Asymmetric Transfer and Asymmetric Intake two-stroke) engine seem quite proper for Formula 1:



The above even-firing Cross-Radial is as vibration free as the best V8, it has firing intervals equal to those of a V8 four-stroke, it has four-stroke-like lubrication (plain bearings, forced / splashed lubrication in the crankcase, oil scraper rings), it utilizes a central scavenging pump (a turbocharger, for instance), etc.



In the above animation they are shown the moving parts of a Cross-Radial PatAT from various viewpoints. The connecting rods and the pistons are properly machined to provide wide bearing surface wherein the heavy loads are taken, keeping at the same time the piston bore low and the crankpin short. A single plane bearing (the yellow part around the crankpin) serves all the connecting rods "unconventionally" (it rotates inside their big ends, being secured to the crankpin).

As a turbocharged Diesel (or direct injection Spark Ignition) it has the qualifications for extreme power to weight ratio and, at the same time, for top fuel efficiency (airplanes, helicopters, paragliding etc).

The above Cross-Radial arrangement minimizes the weight / inertia of the crankshaft.
Other arrangements can also be used (in line, in Vee etc).

The PatATi engine needs neither reed valves, nor rotary valves, nor additional shafts other than the crankshaft. However it has asymmetric transfer and asymmetric intake, like:



All it needs is properly formed connecting rods, pistons and casing.

For more: http://www.pattakon.com/pattakonPatAT.htm

Thanks
Manolis Pattakos

[autogyro]

Check out the 'British' Fairey Rotodyne that the Americans forced us to scrap.

Same with that dog the Lockheed F35, already over five years obsolete and inferior in simulations to anything out there it will meet in combat and it STILL doesnt work.
We are now stuck with two through deck carriers with no catapults, no angled flight decks that will only be able to operate helicopters.

the Rotodyne was scrapped because Napier failed to produce a suitable engine
so the rotor had to be driven by tip ramjets that were about 20 dB noisier than the intended rotor drive
most of the orders for the Rotodyne were American

the last proper UK carrier schemed before the 'carrier ban' (the 422 ?) had anyway abandoned the angled flight deck
yes, since the Harrier really came to exist only because the RN needed it to bypass the ban on carriers ......
subsequent events have been bizarre, the USAF even ordering the stovl F35 versions to force their survival
so acting against the USNs scope to whittle away the position of its USMC
and the UK now has 2 full-size carriers to be equipped with aircraft intended for under-size carriers ?

remember though, any version of the F35 is an order of magnitude stealthier than alternatives eg navalised Typhoon or even Rafale

Sorry Richard I know this is off topic but I have to put the truth out there.
The Rotodyne used a 'compound' engine concept. The Napier Eland turbo jets drove compressors that fed compressed air to the rotor tips. At the tips this air was mixed with fuel to produce a jet to drive the rotor. When the aircraft was scrapped the noise levels had been dropped to well acceptable levels. The Rotodyne was never designed to have any form of 'driven' rotor, its main flight dynamic was as an autogyro. If both engines failed it would simply glide, Try that with an Osprey or even a Chinook.
Stealth is a relative concept. It depend on the level of electronics and the surface material which can be built into anything.
As to the stealth shape of an aircraft, the Vulcan would have been just as good, with slight modifications to the cockpit area and the fin. In any case for the combat environment expected for the 'obsolete' F35 stealth is hardly an essential.
The Lockheed F35 debacle should have seen the fall of both the British and American governments.

The Harrier was NOT designed as a carrier aircraft, it was primarily designed as a battlefield forward positioned strike aircraft, This I know for a fact.
The Royal Navy now has two through deck carriers incapable of operating fixed wing aircraft and unlikely to be operating a strike aircraft that is limited to 9 landings vertical before full engine rebuilds much before 2017 at the earliest.
Heads should roll
Sorry Richard.

Anyway the concept of powered rotors for a man lift device is totally flawed and almost always lethal Manolis.
Not because of your great engine ideas but because of the flight dynamics.
Two strokes for F1 should have been allowed for longer periods, it would have resulted in some useful developments IMO.
With the use of Kers and Hers today it would lend itself to the development of two stroke power sources without crankshafts or con rods an area well worth looking into.

[J.A.W.]

Interesting A-G, I recently read a technical article in the 1957 edition of 'Automobile Year' which reviewed
the connection between 2-stroke & pulse-jet harmonic tech, stating that the promise for shaft applications
ought not be overlooked.. ..& rightly predicted that turbine efficiencies would not translate likewise..

As for the poor bloody Rotodyne.. ..like so many brilliant British ideas it was cruelled by stupid management..

& it did in fact lift off vertically on main rotor thrust (albeit by-pass blown) - just as Manolis intends for his flyer..
..the problem was not due Napier either, as they were then finally cut off at the knees by R-R, which
had finally taken them over after decades of trying, & promptly shut the Napier aero-engine works down..

[autogyro]

Interesting A-G, I recently read a technical article in the 1957 edition of 'Automobile Year' which reviewed
the connection between 2-stroke & pulse-jet harmonic tech, stating that the promise for shaft applications
ought not be overlooked.. ..& rightly predicted that turbine efficiencies would not translate likewise..

As for the poor bloody Rotodyne.. ..like so many brilliant British ideas it was cruelled by stupid management..

& it did in fact lift off vertically on main rotor thrust (albeit by-pass blown) - just as Manolis intends for his flyer..
..the problem was not due Napier either, as they were then finally cut off at the knees by R-R, which
had finally taken them over after decades of trying, & promptly shut the Napier aero-engine works down..

The Rotodyne did take off and land vertically with its rotor 'powered' by the tip jets which were fed not from a by-pass as would be the case with a modern turbo fan version but from two seperate compressors driven by the port and starboard elan turboprop engines.
The aircraft 'transitioned' into an autogyro for level flight with the rotor unpowered.
There was no need for a tail rotor as there was no torque reaction when the rotor was tip jet powered.
Lateral control was by using variable pitch asymmetrically on the two engines.
An unpowered rotor allows for a much higher potential airspeed and a much more efficient lift to fuel used ratio.
A modern Rotodyne would be a match for any short to medium haul fixed wing airliner and would require NO runways.

The two stroke dual crank lift device Manolis is showing is a form of two rotor helicopter.
It would have no useable autorotate facility in the event of engine failure and its pilot control potential would be horrendous.
Far better to use the opposed piston through scavenged concept without the weight of con rods or cranks, to generate electricity to electrically drive a 'transitional' rotor for VTOL at helicopter collective pitch angles of attack and give electrically powered thrust for autogyro flight when the rotor is in reduced angle of attack autogyro mode.
Tried a similar idea over 10 years ago and with modern batteries it could definitely be a workable system.