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#Post#: 7304--------------------------------------------------
Unusual Porting
By: 660magnum Date: February 5, 2012, 4:25 pm
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The following is about a DLE 55 cc Chinese model aircraft reed
valve engine
Notice the regular closed port transfers. Then notice the boost
ports which you normally do not see on a piston ported none reed
valve engine.
[img]
HTML http://img.photobucket.com/albums/v11/jamesirl/ldleg5501.jpg?t=1328479676[/img]
Here is the piston. Notice the big vents on the intake side of
the skirt for the boost ports. Around the wrist pin is open for
the regular closed transfers.
[img]
HTML http://img.photobucket.com/albums/v11/jamesirl/ldleg5504.jpg?t=1328479764[/img]
A picture of the complete engine which turns a 22" diameter 8"
pitch propeller at 7000 rpm
[img]
HTML http://img.photobucket.com/albums/v11/jamesirl/ldleg0055.jpg?t=1328480431[/img]
The Same cylinders are used on a twin
[img]
HTML http://img.photobucket.com/albums/v11/jamesirl/ldleg0111.jpg?t=1328480497[/img]
#Post#: 7305--------------------------------------------------
Re: Unusual Porting
By: 660magnum Date: February 5, 2012, 4:41 pm
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Being as this is a 7000 rpm engine, it does not have a lot of
port timing duration. But it has generous port area.
The spark plugs used in these is a NGK CM-6 Honda generator 10mm
plug. It is a non-resistor plug.
You will notice that the new Husky 550, 555, 560, & 562 engines
use a smaller spark plug which may be a trend of the future?.
#Post#: 7320--------------------------------------------------
Re: Unusual Porting
By: CASE5854x4 Date: February 5, 2012, 9:43 pm
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Cool !!!!!!!!!!!
Steve
#Post#: 7339--------------------------------------------------
Re: Unusual Porting
By: Chainsawrepair Date: February 6, 2012, 2:12 pm
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Thats some wild looking stuff. Thanks for sharing this.
About rpm I thought something was wrong with this last blower I
was working on (first one I checked rpm on). I was like 8000 rpm
what the heck.
Then I started reading on them yesterday and all of them from
28cc to 75cc only go 7K to 8K max rpms. I wonder why that is,
maybe because of the no load like your plane engines?
#Post#: 7340--------------------------------------------------
Re: Unusual Porting
By: Cut4fun Date: February 6, 2012, 2:22 pm
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Thanks for the link w8ye. This is down the road from me beind my
place. I can hear them when they are back there and see the
planes in the ski.
HTML http://www.youtube.com/watch?v=yi6fg7Ig2ZE
#Post#: 7346--------------------------------------------------
Re: Unusual Porting
By: Al Smith Date: February 6, 2012, 5:53 pm
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Couple things .It would almost seem to me on that engine with
the induction straight into the crankcase it would have to have
either a reed or be a rotary valve .My guess seeing the
induction is though the blind end of the crankshaft that it's
rotary . With no piston to block the crank case pressurization
on transfer it would have to use some means to check the flow .
I would be curious to see the port roof angle on the secondaries
/boosters or what ever you call them .It would seem to me they'd
be steep blowing upwards towards the head deck else straight
accross towards the exhaust port they would seem to short
circuit .
Very interesting design I must say .An old gent on the west
coast once had an 090 Stihl renown at one time as the fastest
on the coast .Could be true or an urban legion .
Never the less although he did not go into detail he stated it
used a set of secondaries though piston windows ,through a set
of reed valves for the boosters .He never gave any specifics of
how that was done .
#Post#: 7349--------------------------------------------------
Re: Unusual Porting
By: 660magnum Date: February 6, 2012, 7:17 pm
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Most of the newer design model airplane gasoline engines are
reed valve designs.
The reeds are fiberglass and are usually two opposing each other
in a pyramid shape.
The Chinese engines are not too sophisticated in the hand work
department. The cheapest ones have "as cast" cylinder walls and
bearing pockets. Naturally the transfers are as cast too. The
quality and finish is nothing like Mahle.
The engine in the video above is supposedly made in USA. It is a
Desert Aircraft 120 cc opposed twin with a single carb with
reeds. I think it has tuned cannister mufflers? The company
makes the same cylinder on a 60cc single with reeds.
The kid flying the plane is around 15 yrs old. His dad flies
too.
Here are the reeds from a Chinese DLE 111cc twin
[img]
HTML http://img.photobucket.com/albums/v11/jamesirl/ldleg1111.jpg?t=1328577552[/img]
Here is the reed block from the Chinese DLE 55 single
[img]
HTML http://img.photobucket.com/albums/v11/jamesirl/ldleg5511.jpg?t=1328577752[/img]
#Post#: 7353--------------------------------------------------
Re: Unusual Porting
By: Al Smith Date: February 6, 2012, 9:03 pm
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You can get a lot of surface area in a pyramid reed style design
. As soon as that piston is heading up it's drawing all the way
up 180 degrees .
#Post#: 7355--------------------------------------------------
Re: Unusual Porting
By: 660magnum Date: February 6, 2012, 11:35 pm
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This is the company for your reed valve material
HTML http://www.boyesen.com/
#Post#: 7448--------------------------------------------------
Re: Unusual Porting
By: HolmenTree Date: February 11, 2012, 1:58 pm
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[quote author=Al Smith link=topic=727.msg7346#msg7346
date=1328572433]
Very interesting design I must say .An old gent on the west
coast once had an 090 Stihl renown at one time as the fastest
on the coast .Could be true or an urban legion .
[/quote]
Al it's not an urban legion. I did the same with my Stihl 090 in
the early 1980s. I got the idea with the 2 boost ports in the
pistons intake skirt and addition of a reed valve intake
manifold from a series of 1982 - 83 Chainsaw Age magazines [I
even sent Weimedog copies of the magazines complete build on the
Jonsered 111 project hotsaw last year.]
The p/c setup is very similar between the 090 and 111. The only
thing I didn't do was install the cast iron liner and cut off
head. I got the 090 running pretty fast though with a go kart
34mm Mikuni diaphram alky carb.
The kart reed valve manifold and carb I bought from Russell
Karting out of Kansas City, I don't even know if their still in
business. The 090 I sold many year ago and don't have a clue
where it is today.
30 year old mod techniques are still very repectable today.
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