KR> RE: Posa Carb

[Larry Flesner]

At 07:16 PM 3/21/2010, you wrote:
>A big factor was the difficulty with maintaining correct mixture in cruise
>because fuel flow is related to the "head" of fuel in the tank. "Head" being
>the vertical distance from the surface of the liquid to the carburettor. As
>the level in the tank dropped, flow reduced. The result was mixture was
>hardly ever correct.


Can you believe the Wright brothers flew with a "drip" carb 
setup?  Doesn't sound like the Posa made much progress in 50 or 60 years. :-)

Larry Flesner

KR> RE: Posa Carb

[Alan Taylor]

> We had a Posa carb. and every time it came to start the plane by hand
> propping it would be hard.  The adjustment on the carb is so hard.  You
end
> up to rich or to lean.
>
> We replaced the Posa 40 mm. carb with a AMF 50 mm. carb. from a 1600
Harley
> Davidson MotorCycle.  We run a 1700 cc. Monnet converted VW.   The plane
> starts easy and runs good.

For what it is worth, this was my experience with the POSA carburettor-
Engine - 1835cc VW, prop start with gravity feed, low wing aircraft, fuel in
fuselage behind the firewall.
Carburettor - under the engine, with mixture control, ex HAPI.
 I had to reshape the taper on the needle with a file and micrometer to get
a workable result across the engine speed range.
Eventually I was able to fly but the thing was a brute to start – sometimes
it was easy (very rare).
If, for any reason it stopped, you had to be super quick to turn off the
fuel or you had a flooded situation and a real challenge to get it started
again. Its favourite place to stop was when turning into wind at the end of
the runway; usually when a non POSA trained friend was flying. This habit
was traced to centrifugal effects because it only happened when turning
sharply right. I learned to avoid it – turn gently.
A big factor was the difficulty with maintaining correct mixture in cruise
because fuel flow is related to the “head” of fuel in the tank. "Head" being
the vertical distance from the surface of the liquid to the carburettor. As
the level in the tank dropped, flow reduced. The result was mixture was
hardly ever correct. I blamed this factor for troublesome build up of
deposits on the valves. When in doubt I run rich.
An important relevant law of physics that I have never seen mentioned on the
lists is -
   the flow of liquids due to gravity is proportional
   to the square of the head”.

It is not a simple case of fuel level half as high means half the flow.
Considering the above it may be that a high wing with fuel in the wing could
be a better choice for the POSA. 
Given the above messing about, I quickly ended my love affair with the
simplicity of the POSA. However, I am still a believer in simplicity as
applied to most things. 
I have been given to understand that the POSA was intended for alcohol
fuelled motor cycles where it is common practice to use really excessive
fuel to aid in cooling – not reasonable excess as in aviation engines but in
the really big heaps that you can be used with alcohol over very short
periods of time. In that case some variation of flow can be tolerated.

Alan T
___
Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
please see other KRnet info at http://www.krnet.org/info.html

KR> RE:KR2S Flight Simulator

[robert7...@aol.com]

Mark,

I've done some stuff with X-Planes.  

I created a fairly plane version one of my KR2S. I posted it on my web site 
 at _www.robert7721.com_ (http://www.robert7721.com)  today for anyone  who 
wants to download it. I've got the performance pretty close to what my 
plane  can really do. 

Yes there are others in the KR world who have put together much better  
versions with paint schemes etc. One of these days I'll get my KR2S version  
painted and such, but for now it is still fun to fly. Not as good as the real  
thing of course, but when the weather has been bad this winter, it was 
better  than nothing. 

Thanks,

Rob Schmitt
N1852Z


From: mark wood 
Subject: Re: KR> KR2S  Flight Simulator
To: KRnet 
Message-ID:  <352991c3-15e1-4c7c-b0f7-d2b48b0a0...@mac.com>
Content-Type:  text/plain; charset=US-ASCII; delsp=yes; format=flowed

Have any you guys  done anything with X Planes. With it's blade  
element modeling and  inertial modeling, it has been used in many  
aircraft development  efforts. While I haven't yet modeled a KR, I  
have done other planes  and it is a fairly good representative sim. I  
know that some large  scale operations such as Sino Swerringen   
have used it. I  know a couple of the flight test engineers from there  
and know first  hand.  I've modeled a couple of planes a bit larger  
than the KR2  and have been planning to do one for the KR. My ultimate  
goal is a  true 200 TAS cruise airplane for two. Having said that,  
most of the  designs I've been doing have needed 160-200Hp to  
realistcally achieve  this.


MArk

KR> RE: Posa Carb

[David Rayburn]

What information can send me about the the mixture control and the
Solex  carburetor.

Dave Rayburn  dder...@gmail.com

On Sat, Mar 20, 2010 at 12:19 PM, Joe Beyer  wrote:
> I've run a Posa Super Carb from HAPI for years with good results. They are
> quite a challenge to set them up so the engine will run smoothly in all
> power ranges. I plan on trying a Solex side draft carb soon. I have a
> mixture control for it.
>
> Joe
> Scappoose Ore.
>
>> To: kr...@mylist.net
>> Subject: Re: KR> VW carburation question
>> From: n92...@cox.net
>> Date: Thu, 18 Mar 2010 13:21:38 +
>>
>> If you have a POSA, junk it!
>
>
>
> We had a Posa carb. and every time it came to start the plane by hand
> propping it would be hard.  The adjustment on the carb is so hard.  You end
> up to rich or to lean.
>
> We replaced the Posa 40 mm. carb with a AMF 50 mm. carb. from a 1600 Harley
> Davidson MotorCycle.  We run a 1700 cc. Monnet converted VW.   The plane
> starts easy and runs good.
>
>
>
> Thanks,
>
> John
>
>
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html
>

KR> KR-2 Construction Progress

[smwood]

Most times progress is millimeter by millimeter, a step at a time.
Today I completed the oil plumbing from my 2180 VW to the remote oil filter 
and remote oil cooler and back to the engine.
The CompuFire ignition, Zenith 1821 carb and fuel system are installed. 
Theoretically I could start the engine, but there are a number of other 
systems to do.  So, it will be a few months more before first light off and 
looking for pesky oil leaks.

Sid Wood
Tri-gear KR-2 N6242
Mechanicsville, MD, USA
smw...@md.metrocast.net

KR> Back and forth from Tailwheel to Tricycle

[kleirf...@ecomail.org]

Hey netters,
I was wondering if anyone has pondered the idea of a KR that can be converted
back and forth from a Tailwheel to Tricycle.  I recently discovered that the
Glastar is capable of this.  Here is a link that shows the video, you will have
to go to about the 5:30 point in the video to see this conversion.

http://www.youtube.com/watch?v=UZWRlFa3nOw 

Maybe some way the Diehl nose gear can be installed and removed again and the
main gear can be moved from the front of the spar to the back of the spar.

Kris Leirfallom
CFI 
KR-2 Builder

<>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <><
This email comes to you via solar power at EcoMail! 
Swim over to http://www.ecomail.org to sign up for your *FREE* account

KR> Type-4 engine for sale.

[Marty Martin]

Bob

Is the oil pump the only thing that needs to be replaced?

I looked at the pictures of the motor.  I looks like the crank needs to be
machined again.  Is that right?

So I live in Tehachapi, CA.  Just east of Bakersfield.  My zip is 93561.
What kind of fee for shipping would be looking at?


M. Greg Martin

KR> Type-4 engine for sale.

[badbob]

Hi Bob.

What's the full story with the Type 4 motor?

I have been considering going VW instead of Corvair due to price and
availability of parts here in Australia.
Cheers
Darren Crompton
AUSTRALIA

Hi Darren.

I got the engine with a partially built KR2S. I bought the plane (built stock 
and to the plan specs) for the landing gear, brakes, tires ,wheels, etc..
Also I can ckeck the plans against construction looking at the boat! Even with 
that I made one mistake and had to remove the upper gussets for the firewall!
I am building a really stretched and widened KR2SS and need more HP. If I were 
building a stock KR it would work fine as several people have used them.
So now the engine is for sale. That's my story and I'm stickin' to it!!

Bob Johnson
Willamina, OR USA
badbob0...@embarqmail.com
(971) 645-9491