2 stroke thread (with occasional F1 relevance!)

[coaster]

The bicopter idea i suggested maybe 40 odd pages ago was succesfully taken up another inventor and is a proven concept now.

[nzjrs]

The bicopter idea i suggested maybe 40 odd pages ago was succesfully taken up another inventor and is a proven concept now.

I love a good "I told you so" as much as the next guy, but could you at least provide a couple of links?

[coaster]

Wasnt my idea, it all existed waiting to be realised.

[J.A.W.]

Wasnt my idea, it all existed waiting to be realised.

C'mon now coaster, was the April 1st reveal date missed due to C-19?

This cannot be anything other than a typical youtube spoof/hoax/lark...

No way known can that pissy back-pack with its spindly drives do what is purported.

You might as well superglue some hundreds of angry giant Aussie blowflies to your back,
since they'd at least be attempting to make a 1/2 convincing 2-stroke buzz..

[coaster]

I beleive the context of the conversion with manolis was flight control, his utter beleif in the 'rocket pendulum fallacy' and swinging his body to effect directional control.
I suggested bicopter control as it was proven, we were all way off topic by then as the focus on manolis' opposed 2 stroke was replaced by flight worthyness of his backpack design.

Electric motors aside, manolis could have effected the same control with variable pitch blades and swivelling along the cylinder axis.
(Which the opposed 2 stroke design could not allow)

Anyway, my suggestion fell on deaf ears and ridicule of the 'pendulam fallacy' ensued for 10 pages or so and I left the forum for a while feeling bewilderment.

Speaking of our inventor, how is he?
Are you safe and well manolis?
I pray so.

[nzjrs]

Wasnt my idea, it all existed waiting to be realised.

Nice. After the avatar film came out it was quite cool to see many people building similar models in some of the RC drone forums I follow.

http://jivaro-models.org/samson_sa2/page_samson.html

And others lost to time.

[coaster]

Art imitates life and sometimes vice versa.
I could not read the french, but the pictures tell enough of the story.

[PlatinumZealot]

Wasnt my idea, it all existed waiting to be realised.

I sort of don't like how close the blades are to his neck.
Maybe it has to do with gyration why he has them so low.. But i would feel more comfortable if they were about a foot or two above his head.

Otherwise i like this design the best from an elegance point of view.

[BassVirolla]

Wasnt my idea, it all existed waiting to be realised.

I sort of don't like how close the blades are to his neck.
Maybe it has to do with gyration why he has them so low.. But i would feel more comfortable if they were about a foot or two above his head.

Otherwise i like this design the best from an elegance point of view.

If it happens to have a rotor failure while flying, it's better to have such failure involving your neck before the floor and your spine come into play.

[Pinger]

Hi Manolis, certainly a thoughtfully designed 2T exhaust system which will both
'earn its keep' in power gains to offset its weight, with acceptable output levels
of sound/gas emissions - yet also not be too bulky - is for sure, a needful task.

Here are a couple of ideas in image form, one from the past, & a current one from Rotax.



https://patentimages.storage.googleapis ... D00004.png

With the Rotax system, part of the pulse will enter the turbine of the turbo. What happens to it? Is it swallowed or reflected and if reflected does it change polarity or retain its positive polarity?

[J.A.W.]

Hi Manolis, certainly a thoughtfully designed 2T exhaust system which will both
'earn its keep' in power gains to offset its weight, with acceptable output levels
of sound/gas emissions - yet also not be too bulky - is for sure, a needful task.

Here are a couple of ideas in image form, one from the past, & a current one from Rotax.



https://patentimages.storage.googleapis ... D00004.png

With the Rotax system, part of the pulse will enter the turbine of the turbo. What happens to it? Is it swallowed or reflected and if reflected does it change polarity or retain its positive polarity?

While the sonic pulse does its work, the hot gas efflux likewise does its work on the turbine,
(& snow-mobiles only 'clutch-up' when torque is available to drive the machine), but hey, way
back in the day, Honda did develop their ATAC header-pipe device for 2T use, so perhaps that
aspect is also factored in, by Rotax/BRP.

[Pinger]

An expansion chamber doesn't need gas passing through it to work - only the pulse. But the pulse as it emerges from the exhaust port will split at the branch between the turbo and expansion chamber. What happens with the half that goes into the expansion chamber is obvious. What becomes of the half that enters the turbo? Swallowed, reflected and if reflected, as a positive or negative pulse? Is the turbine an expansion or contraction to a sonic pulse? Different things depending on whether waiting to be spooled up or spooled up with lots of backpressure?

[coaster]

It all depends on having overlap, a certain amount of air fuel will blow straight down the exhaust also.
I tried to clarify which design path of 2 stroke was being followed to further this discussion on the 2 stroke turbo thread as there are 2 design paths for a 2 stroke, detroit diesel style or an expansion exhaust style.
I dont know what the opposed pistons characteristic is for overlap, maybe its perfectly suited to supercharging and not realised yet?

[J.A.W.]

An expansion chamber doesn't need gas passing through it to work - only the pulse. But the pulse as it emerges from the exhaust port will split at the branch between the turbo and expansion chamber. What happens with the half that goes into the expansion chamber is obvious. What becomes of the half that enters the turbo? Swallowed, reflected and if reflected, as a positive or negative pulse? Is the turbine an expansion or contraction to a sonic pulse? Different things depending on whether waiting to be spooled up or spooled up with lots of backpressure?

The sonic-pulse is not going to do an immediate by-pass up a right-angle joint, but the gasses will
find that 'escape hatch' once the piston shuts the ex-ports, & quite obviously, Rotax must've tested
this arrangement against the existing type - which had the turbine at the tail-end of the expansion
chamber - finding sufficient advantage in it, to patent it for their own use.

@ Coaster, the Rotax design features DFI, & variable exhaust port timing via sliding valves, but even
so, that 'free supercharge' sonic-pulse from the expansion chamber is deemed worthwhile keeping...

[coaster]

It would be interesting for Manolis to turbocharge his opposed piston and to measure the gains.