KR> VW prop hub removal

[Roger Bulla]

I have over a 1000 hrs behind VW engines and I am not any more nervous flying 
with them as compared to a Lycoming or Continental. Keep up on maintenance and 
pay attention to the valve train and head setup.

I have removed the prop hub many times while get everything setup the way I 
wanted. My crankshaft and hub is a knock off of the Great Planes Force One 
setup, by TOC in Florida.  When I got the engine the hub was not properly seat 
to the taper on the crankshaft. The back of the hub would hit and the rest of 
the taper was not in contact with the shaft. I had a machine shop take 1/16 of 
an inch off the back of the hub, and this allowed the whole taper to seat. I 
then set the crankshaft in an old flywheel and lapped the two together until 
there is zero run out on the prop hub.

When properly lapped, you can set the prop hub on the crankshaft and it will 
require at tap with a mallet to get it back off. Once it has been torqued, it 
will not move. As Mark said, the keyway is only for indexing. To pull the hub 
back off I put a metal spacer against the crankshaft inside the prop hub and 
and torque a gear puller to the outside of the hub, against the spacer on the 
crank. Must be careful not to over torque and bend the prop hub, then I hit the 
top of the nut on the gear puller with a small sledgehammer. Pops right off 
every time with no damage.  As I said, I have done this many times during setup 
with this current engine and now have over 250 hours on it.  Also, my hub seal 
does not leak so far.

Roger Bulla
rbulla2 at wic.net

KR> VW prop hub connection

[Mark Langford]

Those FAA accident reports are quite sobering, pointing the finger 
almost entirely at engine problems, inadequately prepared pilots, or 
just lack of attention to detail (and then there's the stupidity).

One that caught my attention (and doesn't fit any of the above 
descriptions) is this one regarding a departed propeller.

> The FAA inspector reported that the propeller is attached to a
> flange, which in turn is secured to the Volkswagen engine crankshaft
> by means of a bolt and cotter pin. The pin was found sheared and the
> bolt backed out. Evidence of full thread engagement at some time was
> noted on the bolt. The inspector stated that 5.7 hours of ground run
> and taxi tests had been completed by the pilot prior to this first
> flight.
>
> Probable Cause The failure of the propeller attach bolt retaining
> cotter pin, and the pilot/builder's inadequate preflight inspection
> of the aircraft prior to the attempted flight.

If this hub was anything like my GP hub setup, the determined cause is 
backwards...the hub slipped on the crank taper, and THEN the cotter pin 
sheared, not the other way around.  That little cotter pin couldn't 
possibly keep the hub from spinning on the crank, although somebody 
might think that it would.  That cotter pin is simply an indicator that 
the hub has slipped, and that the taper connection needs immediate 
attention.

Why would the hub slip?  It's as simple as an engine backfire.  When I 
was having problems with my Compufire ignition just before Chino, I 
didn't have enough spark to start the engine when the starter was 
running, but when the ignition was switched off, the coil field would 
collapse and a spark would fire on some cylinder that was charged and 
ready to go, and spin the engine  with a bang and a dramatic shock to 
the crank.

The prop/hub mass makes it reluctant to move, so the hub slips on the 
crank, unscrews the bolt, and shears the cotter pin in the process.  The 
cotter pin will shear right off with that kind of load applied to it. 
Next time the engine starts, the prop comes off, and if you're lucky, it 
lands on the ground nearby, rather than killing somebody or something. 
In my case, it just killed itself on the concrete...$400 down the drain, 
and killed the spinner as well.

I think that bolt should have left-hand threads, be larger diameter, and 
be torqued higher than the manual calls for...like Revmaster does their 
prop hub connection.

Yes, there is also a steel key between crank and hub, but the keyways 
are surprisingly shallow, the key is pretty thin, and it does not always 
offer enough resistance to keep the hub from simply "overriding" the 
key.  The key is also not designed to prevent rotation...it's just there 
to keep your timing mark in the same place every time you rebuild the 
engine.  And when you remove the hub (or it removes itself) and discover 
the key has fallen into the engine (because it was facing down when the 
hub was slid off), you get to tear the engine down to retrieve it!

The moral of this story is be super careful not to misfire the engine, 
and if you do, take a look at that cotter pin and ensure that it's not 
twisted or sheared.  Also, torque that bolt to the high end of the given 
range or higher, and secure it with Loctite 620 (although that still 
wasn't enough in my case).  I'm not trying to start an AD here, but am 
advising those with this hub connection to pay particularly close 
attention to detail during installation.  If you have a bunch of hours 
on it, it's probably going to take a lot of tons on the press to get it 
off, and would probably run without the bolt even installed!

Contrast this hub connection to what you get on even a stock Corvair 
crank...six high-strength 3/8" fine-threaded bolts (formerly holding the 
flywheel on) that practically guarantee the hub isn't going to slip or 
come off the airplane, and removing six bolts and the hub is easily 
removed.  It couldn't be much simpler or more trouble free...

Mark Langford
ML at N56ML.com
http://www.n56ml.com

KR> VW + Prop

[Mike Arnold]

Yes, marnold771 at gmail.com
On Dec 26, 2015 5:17 AM, "Dan Heath via KRnet"  wrote:

> Mike,
>
> Do you have an email address where I can send information?  See my contact
> information below.
>
> My Panther Building Documentation at PantherBuilder Web Site
>
> Daniel R. Heath - Lexington, SC
>
>
> -Original Message-
> From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mike Arnold
> via KRnet
> Sent: Wednesday, December 23, 2015 7:24 PM
> To: KRnet
> Cc: Mike Arnold
> Subject: Re: KR> VW + Prop
>
> What do you want for that engine? What does the cowl fit?
> On Dec 23, 2015 5:25 AM, "Dan Heath via KRnet" 
> wrote:
>
> > If you want a good engine for that heavy KR, I have a Roy Szarafinski
> > Corvair complete except for the exhaust.  I mean complete with
> > Ellison, prop and spinner.  I will throw in the slightly damaged
> > cowling as well.  I want a bigger engine for my Panther.
> >
> >
> >
> > You can contact me at Danrh at Windstream.net
> >
> >
> >
> > See N64KR at  <http://krbuilder.org/> http://KRBuilder.org - Then
> > click on the pics
> >
> >
> >
> > 2015 KR Gathering - McMinnville, OR.  September 3 - 6 -- See U There.
> >
> >
> >
> > Peoples Choice at 2013 - KR Gathering in Mt. Vernon, Il - MVN
> >
> > Best KR at 2013 - KR Gathering in Mt. Vernon, Il - MVN
> >
> > Best Interior at 2013 - KR Gathering in Mt. Vernon, Il - MVN
> >
> > Best Paint at 2013 - KR Gathering in Mt. Vernon, Il - MVN
> >
> > Best Firwwall Forward at 2013 - KR Gathering in Mt. Vernon, Il - MVN
> >
> >
> >
> > Best Interior and Panel at 2008 - KR Gathering in Mt. Vernon, Il - MVN
> >
> >
> >
> >
> >
> > Daniel R. Heath - Lexington, SC
> >
> >
> >
> >
> >
> > -Original Message-
> > From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Tony
> > King via KRnet
> > Sent: Wednesday, December 23, 2015 6:03 AM
> > To: KRnet
> > Cc: Tony King
> > Subject: Re: KR> VW + Prop
> >
> >
> >
> > At 876 lbs empty I'd be looking for a bigger engine than a VW -
> > especially at that altitude and with those temps.  Also, I'm pretty
> > sure 3,000 rpm is a bit low - most of the VW guys seem to go for
> > around 3,400 - 3,600.
> >
> >
> >
> > TK
> >
> >
> >
> > Sent from my iPad
> >
> >
> >
> > > On 23 Dec 2015, at 6:36 PM, PIERRE via KRnet <
> > <mailto:krnet at list.krnet.org> krnet at list.krnet.org> wrote:
> >
> > >
> >
> > > Hi Guys,
> >
> > >
> >
> > >
> >
> > >
> >
> > > It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on
> >
> > > my KR2S (haven't flown yet). The max revs I got was 2,760rpm static.
> >
> > >
> >
> > >
> >
> > >
> >
> > > I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm,
> >
> > > but I only got to 1,850rpm. Stripped the 2 Stromberg 175 cd
> >
> > > carburetors and had them rebuilt - no difference. The main problem
> >
> > > with these numbers is that I can only get to 65mph IAS and it takes
> >
> > > 1,500 feet to get to that speed. The main reason for wanting
> > > 3,000rpm
> >
> > > is that the vw max torque is at 3,000rpm and I think I will then
> > > jump
> >
> > > to heigher rpm and thus more thrust and then higher speeds..
> > > What am
> > I
> > missing?
> >
> > >
> >
> > >
> >
> > >
> >
> > > The KR2S has got wing tanks and tri-cycle gear and is 4" wider in
> > > the
> >
> > > cabin, weight is 876lbs empty, so she is a bit heavier that she
> > > should
> >
> > > be. (I am 176lbs and 5ft 8in) My altitude is 5,500feet ASL and the
> >
> > > temps we had is between 89 degrees and 108 degrees Fahrenheit. (32
> >
> > > degrees - 42 degrees
> >
> > > centigrade)
> >
> > >
> >
> > >
> >
> > >
> >
> > > Hope somebody can help!
> >
> > >
> >
> > >
> >
> > >
> >
> > > Cheers,
> >
> > >
> >
> > > Pierre
> >
> > >
> >
> >

KR> VW + Prop

[Dan Heath]

Mike,

Do you have an email address where I can send information?  See my contact
information below.

My Panther Building Documentation at PantherBuilder Web Site

Daniel R. Heath -?Lexington, SC


-Original Message-
From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mike Arnold
via KRnet
Sent: Wednesday, December 23, 2015 7:24 PM
To: KRnet
Cc: Mike Arnold
Subject: Re: KR> VW + Prop

What do you want for that engine? What does the cowl fit?
On Dec 23, 2015 5:25 AM, "Dan Heath via KRnet"  wrote:

> If you want a good engine for that heavy KR, I have a Roy Szarafinski 
> Corvair complete except for the exhaust.  I mean complete with 
> Ellison, prop and spinner.  I will throw in the slightly damaged 
> cowling as well.  I want a bigger engine for my Panther.
>
>
>
> You can contact me at Danrh at Windstream.net
>
>
>
> See N64KR at  <http://krbuilder.org/> http://KRBuilder.org - Then 
> click on the pics
>
>
>
> 2015 KR Gathering - McMinnville, OR.  September 3 - 6 -- See U There.
>
>
>
> Peoples Choice at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
> Best KR at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
> Best Interior at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
> Best Paint at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
> Best Firwwall Forward at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
>
>
> Best Interior and Panel at 2008 - KR Gathering in Mt. Vernon, Il - MVN
>
>
>
>
>
> Daniel R. Heath - Lexington, SC
>
>
>
>
>
> -Original Message-
> From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Tony 
> King via KRnet
> Sent: Wednesday, December 23, 2015 6:03 AM
> To: KRnet
> Cc: Tony King
> Subject: Re: KR> VW + Prop
>
>
>
> At 876 lbs empty I'd be looking for a bigger engine than a VW - 
> especially at that altitude and with those temps.  Also, I'm pretty 
> sure 3,000 rpm is a bit low - most of the VW guys seem to go for 
> around 3,400 - 3,600.
>
>
>
> TK
>
>
>
> Sent from my iPad
>
>
>
> > On 23 Dec 2015, at 6:36 PM, PIERRE via KRnet <
> <mailto:krnet at list.krnet.org> krnet at list.krnet.org> wrote:
>
> >
>
> > Hi Guys,
>
> >
>
> >
>
> >
>
> > It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on
>
> > my KR2S (haven't flown yet). The max revs I got was 2,760rpm static.
>
> >
>
> >
>
> >
>
> > I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm,
>
> > but I only got to 1,850rpm. Stripped the 2 Stromberg 175 cd
>
> > carburetors and had them rebuilt - no difference. The main problem
>
> > with these numbers is that I can only get to 65mph IAS and it takes
>
> > 1,500 feet to get to that speed. The main reason for wanting 
> > 3,000rpm
>
> > is that the vw max torque is at 3,000rpm and I think I will then 
> > jump
>
> > to heigher rpm and thus more thrust and then higher speeds.. 
> > What am
> I
> missing?
>
> >
>
> >
>
> >
>
> > The KR2S has got wing tanks and tri-cycle gear and is 4" wider in 
> > the
>
> > cabin, weight is 876lbs empty, so she is a bit heavier that she 
> > should
>
> > be. (I am 176lbs and 5ft 8in) My altitude is 5,500feet ASL and the
>
> > temps we had is between 89 degrees and 108 degrees Fahrenheit. (32
>
> > degrees - 42 degrees
>
> > centigrade)
>
> >
>
> >
>
> >
>
> > Hope somebody can help!
>
> >
>
> >
>
> >
>
> > Cheers,
>
> >
>
> > Pierre
>
> >
>
> > ___
>
> > Search the KRnet Archives at  
> > <http://tugantek.com/archmailv2-kr/search>
> http://tugantek.com/archmailv2-kr/search.
>
> > To UNsubscribe from KRnet, send a message to
>
> >  <mailto:KRnet-leave at list.krnet.org> KRnet-leave at list.krnet.org 
> > please
> see
> other KRnet info at
>
> >  <http://www.krnet.org/info.html> http://www.krnet.org/info.html see
>
> >  <http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org>
> http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change
>
> > options
>
>
>
> ___
>
> Search the KRnet Archives at  
> <http://tugantek.com/archmailv2-kr/search>
> http://tugantek.com/archmailv2-kr/search.
>
> To UNsubscribe from KRnet, send a message to 
> <mailto:KRnet-leave at list.krnet.org> KRnet-leave a

KR> VW + Prop

[PIERRE]

Many, many thanks for the responses guys!!

I'm of to the field now and will check timing. I know I've set timing at 25
degrees at 2,500rpm, so will advance to 30 degrees and see if there is a
difference. Will shorten the 48X52" prop to 50" and see what happens. After
reading the responses (and thinking a bit) it does seem rather stupid to
have increased the length with less pitch on the new prop. Will keep that
prop as a show piece if the "old" prop works, thanks Phillip I am making
notes on all these "rules of thumb".

> As a data point, I can turn 3200 rpm static and turn it up to 3450 or so
wide open with a 2180cc engine with 8.6:1 compression ratio and 30 degrees
of advance at wide open throttle.  I would be reluctant to take off with
only 3000 rpm with my short runway

Thanks again and I will use Mark's numbers as reference. I will check
compression as well. I would love to get 3400rpm, but am now aiming a bit
lower as reality sets in.. 

> FWIW, while my KR is a bit lighter than yours, I am significantly heavier
than you and fly my KR at 1200# gross based at an airport at 7200' MSL  

I must say I feel a lot better after reading the above! Thanks  Jeff, I will
probably also have all up weight in the 1200lbs region!!!

> Not enough engine

I don't really want to acknowledge this one, but I had this nagging feeling
for the last few months... The engine is a standard VW 2 liter Kombi engine.
According to the rebuilders and aero modification guys in South Africa the
specs are as follows: (measured at sea level)

RPM 10001500200025003000350040004500
50005500
TORQUE  39.369.679.792.8105 105 97.683.166
49.8
H/POWER 7.5 19.930.444.259.970  74.371.262.8
52.1
EXHAUST P   0   0.1 0.1 0.020.3 0.5 0.6 0.6
0.6 0.7
Fuel Flow   10.316.721.327.134.140.244  46.5
47.848.6  

I might start looking for a Corvair engine in February..

Blessed Christmas to you all!
Pierre

KR> VW + Prop

[laser147 at juno.com]

Mark said,  

"I meant 54x52.   . . . wanted to be able to cut it down . . ."

Just coincidentally that Sterba 52 x 52 I had that I sent back to Ken
Cottle started life as a 54 x 52.  He originally had a HAPI 1835 on my
KR-1? so cut one inch off of each tip to get more speed back when he and
Jim Faughn were terrorizing the countryside in the late 80's, early 90's.
 That prop went with the plane when Steve Bennett bought it and Steve
just left it on the plane when he replaced the HAPI with his 2180.  Steve
just flew it with reduced throttle at lower altitudes.  The 52 x 52
didn't suit my kind of flying at all but for short periods the plane
would sure go like a bat with it.  I soon took it off and put the Prince
52 x 54 on.  

Since it was just sitting I sent this prop back to Sterba to refinish and
hopefully "put a little more pitch" into it.  When I got it back this 25+
year old prop looked like new but it still turned way too fast so I was
glad that Ken needed it for his current KR (one of Sam Bailey's three
KR's, now much improved by Ken).  This prop wound up back where it
started almost 30 years before.  

That prop, as well as my current 52 x 56, has what Sterba calls his
"Sweptback" profile as opposed to his "Race" profile.  The former has a
straight leading edge that makes a sharp narrowing about halfway to the
tip.  My Prince has the same profile.  Sterba's "Race" profile has a long
curving leading edge more like the typical Sensenich.  It would be
interesting to put the two Sterba planforms, same length and pitch, on
the same engine and measure thrust at a given RPM and see which one
produces more thrust.  Ed must have done that comparison somewhere along
the way . . . it would be interesting to ask him about it.  

Both of my Sterbas have been the maple/cherry alternate lamination thing
that he does.  Makes for a really nice looking prop at great prices. 
BTW, Ed refinished that prop and didn't charge anything.

The Prince needed refinishing ($300+) after I went through some
significant rain on one of my trips back east.  When I got it back from
Lonnie I just left it in its shipping box where it still sits.  Really
gorgeous prop, but useless.

Mike
KSEE


Ally Bank, Member FDIC
Consistently competitive rates, 24/7 customer care, Member FDIC
http://thirdpartyoffers.juno.com/TGL3141/567c4abf10c3d4abe1cb8st01vuc

KR> VW + Prop

[Wayne]

Hello pierre!

Here is the premier Type-4 engine specialist.

http://type4store.com

Very pricy, but they have it all.

I gave away a nice 2L type-4 because it was to expensive to make it into 
a flight motor. The Raby people do have what you need though and they 
have experience with flight motors. Very nice folks.

Good Luck,

Wayne DeLisle Sr.

-

> KR> VW + Prop
>
> PIERRE pierre at d-toxdebt.co.za
> Wed Dec 23 03:36:28 EST 2015
>
> Hi Guys,
>
> It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on my KR2S
> (haven't flown yet). The max revs I got was 2,760rpm static.
> --

KR> VW + Prop

[Mark Langford]

Pierre wrote:

 >The engine is a standard VW 2 liter Kombi engine.

70 HP tells the story, but you should still be able to a 52x48 prop up 
higher than that.  I still say that one prop maker's pitch is not 
necessarily the same as another's.

The good news is that it's a Type 4 engine, rather than a Type 1.  With 
  a stroker crank and larger  pistons and cylinders, you turn that 
2000cc engine into a 2600cc engine that's almost as big as a 2700cc 
Corvair.  That would give you 90 HP.  A higher lift cam will likely give 
you a few more, maybe 95 HP.  That should improve things considerably. 
Parts availability for the Type 4 engine is not so great, since they 
don't make the heads or cases anymore, but the same can be said for the 
Corvair.  Great Plains Aircraft (GPASC) at 
http://greatplainsas.com/index.html used to make a stroker crank with 
tapered hub for the Type 4, but I don't know for sure that they still do.

Having just rebuilt a Type 1 that I am currently flying behind, and 
having put 1100 hours on a Corvair, I will have to say that the Corvair 
is a very simple solution also, now that the crank issue has been 
resolved with a 4340 crank.  But given limited parts availability for 
the Corvair in your part of the world, a used O-200 makes a lot of sense 
for your KR2S, and would probably be less expensive in the long run...

Mark Langford
ML at N56ML.com
http://www.n56ml.com

KR> VW + Prop

[Dan Heath]

For all inquiries regarding the Corvair engine, please contact me off net so
I can give you a personal reply.



The cowl was for the Corvair on a KR2.



Danrh at Windstream.net



See N64KR at   http://KRBuilder.org - Then click on
the pics 



2015 KR Gathering - McMinnville, OR.  September 3 - 6 -- See U There.



Peoples Choice at 2013 - KR Gathering in Mt. Vernon, Il - MVN 

Best KR at 2013 - KR Gathering in Mt. Vernon, Il - MVN 

Best Interior at 2013 - KR Gathering in Mt. Vernon, Il - MVN 

Best Paint at 2013 - KR Gathering in Mt. Vernon, Il - MVN 

Best Firwwall Forward at 2013 - KR Gathering in Mt. Vernon, Il - MVN 



Best Interior and Panel at 2008 - KR Gathering in Mt. Vernon, Il - MVN





Daniel R. Heath - Lexington, SC

KR> VW + Prop

[Tony King]

At 876 lbs empty I'd be looking for a bigger engine than a VW - especially at 
that altitude and with those temps.  Also, I'm pretty sure 3,000 rpm is a bit 
low - most of the VW guys seem to go for around 3,400 - 3,600.

TK

Sent from my iPad

> On 23 Dec 2015, at 6:36 PM, PIERRE via KRnet  wrote:
> 
> Hi Guys,
> 
> 
> 
> It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on my KR2S
> (haven't flown yet). The max revs I got was 2,760rpm static.
> 
> 
> 
> I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm, but I
> only got to 1,850rpm. Stripped the 2 Stromberg 175 cd carburetors and had
> them rebuilt - no difference. The main problem with these numbers is that I
> can only get to 65mph IAS and it takes 1,500 feet to get to that speed. The
> main reason for wanting 3,000rpm is that the vw max torque is at 3,000rpm
> and I think I will then jump to heigher rpm and thus more thrust and then
> higher speeds.. What am I missing?
> 
> 
> 
> The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the cabin,
> weight is 876lbs empty, so she is a bit heavier that she should be. (I am
> 176lbs and 5ft 8in) My altitude is 5,500feet ASL and the temps we had is
> between 89 degrees and 108 degrees Fahrenheit. (32 degrees - 42 degrees
> centigrade)
> 
> 
> 
> Hope somebody can help!
> 
> 
> 
> Cheers,
> 
> Pierre
> 
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change 
> options

KR> VW + prop

[Mark Langford]

Mike Stirewalt wrote:

> Are you sure you've got a 52 x 54 and not a 52 x 52? Your figures sound
> like a 52 x 52. You did some magic ju ju to that engine when you
> re-built it recently if you indeed have a Sterba 52 x 54 and are
> getting 3450.

Sorry...dyslexia there.  I meant 54x52. But I'm not sure there's a lot 
of difference there.  I ordered the larger diameter because I'm not very 
worried about killing the prop (as long as I'm on a runway), and wanted 
to be able to cut it down if it wouldn't turn up high enough to develop 
power.  I'll probably live long enough to eat those words, however.

I had a 52x52 and it would turn up to something like 3700 rpm wide open, 
which is a little too much for my taste.  If nothing else, this lends 
some credence to my theory that Ed's pitch numbers tend to be on the 
high side.

I got three more hours on it last weekend, and probably 15 more 
landings.  I tried to get Larry and Joe to meet me in West Virginia, but 
I got these lame excuses like "I'm sick as a dog and may die", and 
"Sorry, I'm on my way to California".  Some people!

Regarding the TruTrak ECO, It certainly is perfect for me. I refuse to 
waste another penny buying more MGL stuff (like $1500 for two servos to 
get two-axis autopilot out of the iEFIS), so this is a no-brainer, and 
light. I've requested dimensions, although it appears as though the 
servos should fit in a KR wing. Not so sure about the elevator though.

See photo below (just to make sure I got it right this time).  I was 
going to the hangar to re-torque the prop anyway, as well as adjust the 
valves again...

Mark Langford
ML at N56ML.com
http://www.n56ml.com

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KR> VW + Prop

[Kenneth Wiltrout]

I have a 54/48 on the front of a 2100 Revmaster in my 2S. I originally had a 
54/50 but wanted a better climb so I had it repitched. I'm 3000 static and was 
just slightly less before the repitch. Cruise speed (135 mph ) at 3300 didn't 
really seem to change much.
N6399UKenny Wiltrout 

On Wednesday, December 23, 2015 10:29 AM, Jeff Scott via KRnet  wrote:


 Pierre,

Your first prop was closer to what you need, but quite honestly, you just don't 
have enough engine to turn the prop at that density altitude.? People get all 
wrapped around the axle about pitch, but tip drag is also a big issue.? You 
don't say what the displacement of your VW engine might be, but it's pretty 
clear that you are pushing it's limits.? With the Density Altitudes you are 
looking at, an 80 HP VW isn't going to make more than 60HP.? You are going to 
need a short prop to turn the RPMs you want, so the prop efficiency is going to 
be off pretty badly on take off.? Even with an optimistic number of 75% 
efficiency during take off, you are only getting at best 45 HP to pull your 
plane into the air.? 

When I ran into this problem with a VW powerplant on one of the planes I built, 
I sent the prop back to have some pitch taken out of it.? When I got the prop 
back, it made no detectable difference in RPM.? After a discussion with the 
prop maker, per his direction I marked off each prop tip with 1/8" increments 
from the tip.? I'd fly the prop, then cut off 1/8" and fly it again.? It was a 
trade off between picking up engine performance at the cost of prop 
efficiency.? With each cut, I got an improvement in RPMs.? I kept going until I 
picked up more rpm, but lost performance due to decreased prop efficiency.? 
That was where the prop stayed for the next 40 or so hours.? Ultimately I 
concluded that while the 2180 VW I had on that plane had sufficient HP for the 
application, and would be a decent performing aircraft at sea level, the high 
reving engine and slow airplane combination with marginal power at my high 
altitude airport just wasn't going to be safe to fly.

FWIW, while my KR is a bit lighter than yours, I am significantly heavier than 
you and fly my KR at 1200# gross based at an airport at 7200' MSL.? I operate 
with density altitudes from 7000 to greater than 10,000'.? Even with my hopped 
up O-200 powerplant, depending on the DA and weight, I never get off in less 
than 2000' and if heavily loaded on a hot day can take up to 3000' of runway.? 
Additionally, I see a 550 rpm difference between what I turn at full throttle 
on take off run vs what I turn in cruise when the prop starts to unload.? 
Thinking about it in those terms, your first prop may very well turn up to 
around 3300 RPM once your plane is airborne and pushed over into cruise.? Those 
that have seen me operate at sea level can attest that my KR is not a ground 
loving pig and in fact is a pretty good performer under normal conditions.? 

That's the price we pay for living up in the mountains.

-Jeff Scott
Los Alamos, NM

?
?


Hi Guys,

It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on my KR2S
(haven't flown yet). The max revs I got was 2,760rpm static.

I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm, but I
only got to 1,850rpm. Stripped the 2 Stromberg 175 cd carburetors and had
them rebuilt - no difference. The main problem with these numbers is that I
can only get to 65mph IAS and it takes 1,500 feet to get to that speed. The
main reason for wanting 3,000rpm is that the vw max torque is at 3,000rpm
and I think I will then jump to heigher rpm and thus more thrust and then
higher speeds.. What am I missing?

The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the cabin,
weight is 876lbs empty, so she is a bit heavier that she should be. (I am
176lbs and 5ft 8in) My altitude is 5,500feet ASL and the temps we had is
between 89 degrees and 108 degrees Fahrenheit. (32 degrees - 42 degrees
centigrade)



Hope somebody can help!



Cheers,

Pierre

___
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KR> VW + Prop

[Mike Arnold]

Robert where are you in Missouri
On Dec 23, 2015 8:00 AM, "Robert7721 via KRnet" 
wrote:

> Pierre,
>
>
> Hate to say this, but I don't think this plane is going to be safe to fly
> as is.  If you are truly at 5500 ft, and empty weight is 876, the VW is
> probably not going to be enough engine. Specially at the temperatures (89
> -108) you are stating.
>
>
> Your 1st prop was closer to what you need. Steve Bennett at Great Plains
> (VW Seller)  basically said you need about 2900 rpm static to be sure you
> were good.  The RPM will climb up once you are in the air and moving.
>
>
> I'm running a VW (Revmaster 2100D) and a 1500 ft roll to get 65 mph at
> 5500 ft is actually good in my opinion. I know I used up quite a bit more
> on a trip from the Midwest USA to California over some serious mountains in
> 2014. There were a couple airports I landed/took off at with elevations
> over 5500 ft. But my empty weight is closer to 650 pounds. My best climb
> rate was maybe 300-400 ft/min at those elevations. I do normally get about
> 800 fpm climb at my home airport in Missouri (1000 ft MSL).
>
>
> Options, 1st I'd go back to the 1st Prop and Carb set up. That was close.
> I believe someone else already commented that increasing the length to 54"
> was a bad idea - that is correct. Normally, you shorten the prop to
> increase RPMs.  Lowering the pitch usually helps as well with increasing
> the rpm, but length is a factor as well.
>
>
> Also,
>
>
> 1. Can you relocate to a lower elevation for initial testing?
> 2. Wait for cooler weather?
>
>
>
>
> Rob Schmitt
> N1852Z
> www.robert7721.com
>
>
>
>
> -Original Message-
> From: PIERRE via KRnet 
> To: krnet 
> Cc: PIERRE 
> Sent: Wed, Dec 23, 2015 2:37 am
> Subject: KR> VW + Prop
>
> Hi Guys,
>
>
>
> It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on my
> KR2S
> (haven't flown yet). The max revs I got was 2,760rpm static.
>
>
>
> I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm, but I
> only got to 1,850rpm. Stripped the 2 Stromberg 175 cd carburetors and had
> them rebuilt - no difference. The main problem with these numbers is that I
> can only get to 65mph IAS and it takes 1,500 feet to get to that speed. The
> main reason for wanting 3,000rpm is that the vw max torque is at 3,000rpm
> and I think I will then jump to heigher rpm and thus more thrust and then
> higher speeds.. What am I missing?
>
>
>
> The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the
> cabin,
> weight is 876lbs empty, so she is a bit heavier that she should be. (I am
> 176lbs and 5ft 8in) My altitude is 5,500feet ASL and the temps we had is
> between 89 degrees and 108 degrees Fahrenheit. (32 degrees - 42 degrees
> centigrade)
>
>
>
> Hope somebody can help!
>
>
>
> Cheers,
>
> Pierre
>
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
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> options
>
> ___
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> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
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>

KR> VW + Prop

[Mike Arnold]

What do you want for that engine? What does the cowl fit?
On Dec 23, 2015 5:25 AM, "Dan Heath via KRnet"  wrote:

> If you want a good engine for that heavy KR, I have a Roy Szarafinski
> Corvair complete except for the exhaust.  I mean complete with Ellison,
> prop
> and spinner.  I will throw in the slightly damaged cowling as well.  I want
> a bigger engine for my Panther.
>
>
>
> You can contact me at Danrh at Windstream.net
>
>
>
> See N64KR at  <http://krbuilder.org/> http://KRBuilder.org - Then click on
> the pics
>
>
>
> 2015 KR Gathering - McMinnville, OR.  September 3 - 6 -- See U There.
>
>
>
> Peoples Choice at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
> Best KR at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
> Best Interior at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
> Best Paint at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
> Best Firwwall Forward at 2013 - KR Gathering in Mt. Vernon, Il - MVN
>
>
>
> Best Interior and Panel at 2008 - KR Gathering in Mt. Vernon, Il - MVN
>
>
>
>
>
> Daniel R. Heath - Lexington, SC
>
>
>
>
>
> -Original Message-
> From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Tony King
> via
> KRnet
> Sent: Wednesday, December 23, 2015 6:03 AM
> To: KRnet
> Cc: Tony King
> Subject: Re: KR> VW + Prop
>
>
>
> At 876 lbs empty I'd be looking for a bigger engine than a VW - especially
> at that altitude and with those temps.  Also, I'm pretty sure 3,000 rpm is
> a
> bit low - most of the VW guys seem to go for around 3,400 - 3,600.
>
>
>
> TK
>
>
>
> Sent from my iPad
>
>
>
> > On 23 Dec 2015, at 6:36 PM, PIERRE via KRnet <
> <mailto:krnet at list.krnet.org> krnet at list.krnet.org> wrote:
>
> >
>
> > Hi Guys,
>
> >
>
> >
>
> >
>
> > It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on
>
> > my KR2S (haven't flown yet). The max revs I got was 2,760rpm static.
>
> >
>
> >
>
> >
>
> > I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm,
>
> > but I only got to 1,850rpm. Stripped the 2 Stromberg 175 cd
>
> > carburetors and had them rebuilt - no difference. The main problem
>
> > with these numbers is that I can only get to 65mph IAS and it takes
>
> > 1,500 feet to get to that speed. The main reason for wanting 3,000rpm
>
> > is that the vw max torque is at 3,000rpm and I think I will then jump
>
> > to heigher rpm and thus more thrust and then higher speeds.. What am
> I
> missing?
>
> >
>
> >
>
> >
>
> > The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the
>
> > cabin, weight is 876lbs empty, so she is a bit heavier that she should
>
> > be. (I am 176lbs and 5ft 8in) My altitude is 5,500feet ASL and the
>
> > temps we had is between 89 degrees and 108 degrees Fahrenheit. (32
>
> > degrees - 42 degrees
>
> > centigrade)
>
> >
>
> >
>
> >
>
> > Hope somebody can help!
>
> >
>
> >
>
> >
>
> > Cheers,
>
> >
>
> > Pierre
>
> >
>
> > ___
>
> > Search the KRnet Archives at  <http://tugantek.com/archmailv2-kr/search>
> http://tugantek.com/archmailv2-kr/search.
>
> > To UNsubscribe from KRnet, send a message to
>
> >  <mailto:KRnet-leave at list.krnet.org> KRnet-leave at list.krnet.org please
> see
> other KRnet info at
>
> >  <http://www.krnet.org/info.html> http://www.krnet.org/info.html see
>
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> http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change
>
> > options
>
>
>
> ___
>
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>
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> see
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>

KR> VW + Prop

[Jeff Scott]

Pierre,

Your first prop was closer to what you need, but quite honestly, you just don't 
have enough engine to turn the prop at that density altitude.  People get all 
wrapped around the axle about pitch, but tip drag is also a big issue.  You 
don't say what the displacement of your VW engine might be, but it's pretty 
clear that you are pushing it's limits.  With the Density Altitudes you are 
looking at, an 80 HP VW isn't going to make more than 60HP.  You are going to 
need a short prop to turn the RPMs you want, so the prop efficiency is going to 
be off pretty badly on take off.  Even with an optimistic number of 75% 
efficiency during take off, you are only getting at best 45 HP to pull your 
plane into the air.  

When I ran into this problem with a VW powerplant on one of the planes I built, 
I sent the prop back to have some pitch taken out of it.  When I got the prop 
back, it made no detectable difference in RPM.  After a discussion with the 
prop maker, per his direction I marked off each prop tip with 1/8" increments 
from the tip.  I'd fly the prop, then cut off 1/8" and fly it again.  It was a 
trade off between picking up engine performance at the cost of prop efficiency. 
 With each cut, I got an improvement in RPMs.  I kept going until I picked up 
more rpm, but lost performance due to decreased prop efficiency.  That was 
where the prop stayed for the next 40 or so hours.  Ultimately I concluded that 
while the 2180 VW I had on that plane had sufficient HP for the application, 
and would be a decent performing aircraft at sea level, the high reving engine 
and slow airplane combination with marginal power at my high altitude airport 
just wasn't going to be safe to fly.

FWIW, while my KR is a bit lighter than yours, I am significantly heavier than 
you and fly my KR at 1200# gross based at an airport at 7200' MSL.  I operate 
with density altitudes from 7000 to greater than 10,000'.  Even with my hopped 
up O-200 powerplant, depending on the DA and weight, I never get off in less 
than 2000' and if heavily loaded on a hot day can take up to 3000' of runway.  
Additionally, I see a 550 rpm difference between what I turn at full throttle 
on take off run vs what I turn in cruise when the prop starts to unload.  
Thinking about it in those terms, your first prop may very well turn up to 
around 3300 RPM once your plane is airborne and pushed over into cruise.  Those 
that have seen me operate at sea level can attest that my KR is not a ground 
loving pig and in fact is a pretty good performer under normal conditions.  

That's the price we pay for living up in the mountains.

-Jeff Scott
Los Alamos, NM

?
?


Hi Guys,

It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on my KR2S
(haven't flown yet). The max revs I got was 2,760rpm static.

I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm, but I
only got to 1,850rpm. Stripped the 2 Stromberg 175 cd carburetors and had
them rebuilt - no difference. The main problem with these numbers is that I
can only get to 65mph IAS and it takes 1,500 feet to get to that speed. The
main reason for wanting 3,000rpm is that the vw max torque is at 3,000rpm
and I think I will then jump to heigher rpm and thus more thrust and then
higher speeds.. What am I missing?

The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the cabin,
weight is 876lbs empty, so she is a bit heavier that she should be. (I am
176lbs and 5ft 8in) My altitude is 5,500feet ASL and the temps we had is
between 89 degrees and 108 degrees Fahrenheit. (32 degrees - 42 degrees
centigrade)



Hope somebody can help!



Cheers,

Pierre

KR> VW + Prop

[Phillip Hill]

General rule, a reduction in diameter of 1" (1/2" taken from each blade)
will yield an increase in rpm of 100 rpm. So take that original prop down
to 50" diameter and you will have your 2900 rpm. That's an easy mod to do,
just re balance it and you're done.

On Wed, Dec 23, 2015, 8:04 AM Mark Langford via KRnet 
wrote:

> Pierre wrote:
>
> >> It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on
> my KR2S> (haven't flown yet). The max revs I got was 2,760rpm static.<<
>
> Depending on the displacement of the VW engine, you likely need less
> pitch (as others were quick to point out).  The way the prop maker
> measures pitch is important also.  Having had about 20 different props
> on my KR2S and KR2, I can tell you that the pitch numbers vary wildly,
> with respect to RPM.  Sterba, for example is almost always has higher
> pitch numbers for a prop that would turn the same RPM from somebody
> else.  Tennessee props tends to be nearer to Sterba than others.
>
> If you haven't seen it already, take a look at the prop vs engine
> numbers listed for fifty different KRs at
> http://www.krnet.org/kr-info.html .  That may help you narrow it down.
>
> Another issue is are you sure the ignition timing is correct?  It's
> worth double checking everything involved in making that right (TDC
> mark, for example). Ignition timing is everything.  Checked at 2700 rpm
> or above for full advance to 30 degrees? That eliminates advance issues.
> I know it's a real pain to check timing with a a propeller installed,
> and very dangerous, so I've started doing it before the prop is even
> installed. Given that I do have a flywheel on the back of the engine for
> the starter and alternator, it's not going to hurt the engine for a few
> minutes, and it allows precise setting of the timing without the
> adventure of a prop being there.  What a huge difference in pucker factor!
>
> And you know for a fact that the cam timing is dead on?  Have you
> considered having the 48x52 repitched to something a little less?  At
> least that way you have two data points.
>
> As a data point, I can turn 3200 rpm static and turn it up to 2450 or so
> wide open with a 2180cc engine with 8.6:1 compression ratio and 30
> degrees of advance at wide open throttle.  I would be reluctant to take
> off with only 3000 rpm with my short runway.
>
> Mark Langford
> ML at N56ML.com
> http://www.n56ml.com
>
>
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
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> options
>

KR> VW + prop

[laser147 at juno.com]

Langford said, 

"I'm now flying a "52x54" Sterba prop on the 650 pound KR2.  As the
engine gets broken in, I expect the RPMs to come up a bit more also,
maybe 3500 or so."

You really did something special to Faughn's old engine to be getting
those numbers, especially with single ignition.  With my Prince 52 x 54
the best I can get is 3150 - which is all I want.  I'd still be using
that prop if it didn't have those drag-inducing "P-tips" (read Paul Lipps
if anyone wants to argue about that) and if it had leading edges that
held up in rain (as do Sterba's urethane edges).  My current Sterba 52 x
56 gives me 3150 at altitude WOT.  That's right around 80% of Mach on the
tip speed so anything faster is just creating tip drag and generating
more internal friction heat.  3100 is the most efficient RPM for a 52
inch prop and seems to be the "happy place" for my GP2180 as well. 

Anyway Mark, 3450 on a 2180 with a Sterba 52 x 54 is phenomenol.  What
did you do to that old engine?   

Are you sure you've got a 52 x 54 and not a 52 x 52?   I had a 52 x 52
Sterba that I have since sent to Ken Cottle for use on his current KR. 
He needs the RPM for getting in and out of short grass strips.  That prop
would render 3450-3500 and of course send the oil and cylinder head temps
off the chart while doing so.  Your figures sound like a 52 x 52.  You
did some magic ju ju to that engine when you re-built it recently if you
indeed have a Sterba 52 x 54 and are getting 3450.  Sounds like for the
sake of keeping your engine temps down you'll be moving to a 52 x 56 at
some point.

Mike
KSEE


Ally Bank, Member FDIC
Consistently competitive rates, 24/7 customer care, Member FDIC
http://thirdpartyoffers.juno.com/TGL3141/567afbfab430f7bfa3aaast01vuc

KR> VW + Prop

[PIERRE]

Hi Guys,



It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on my KR2S
(haven't flown yet). The max revs I got was 2,760rpm static.



I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm, but I
only got to 1,850rpm. Stripped the 2 Stromberg 175 cd carburetors and had
them rebuilt - no difference. The main problem with these numbers is that I
can only get to 65mph IAS and it takes 1,500 feet to get to that speed. The
main reason for wanting 3,000rpm is that the vw max torque is at 3,000rpm
and I think I will then jump to heigher rpm and thus more thrust and then
higher speeds.. What am I missing?



The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the cabin,
weight is 876lbs empty, so she is a bit heavier that she should be. (I am
176lbs and 5ft 8in) My altitude is 5,500feet ASL and the temps we had is
between 89 degrees and 108 degrees Fahrenheit. (32 degrees - 42 degrees
centigrade)



Hope somebody can help!



Cheers,

Pierre

KR> VW + Prop

[Dan Heath]

I never had a problem cooling my Type 1, once I put on the Revmaster oil
cooler.  The oil cooler on top, is not enough for a 2180+ VW.  Works great
on the 1835 and such, but not on the larger displacement engines.

My Panther Building Documentation at PantherBuilder Web Site

Daniel R. Heath -?Lexington, SC

-Original Message-

My experience with the Type 1 is that it's "cooling challenged" when
compared to the Corvair, mainly because head fin area is very limited.

KR> VW + Prop

[Robert7721]

Pierre,


Hate to say this, but I don't think this plane is going to be safe to fly as 
is.  If you are truly at 5500 ft, and empty weight is 876, the VW is probably 
not going to be enough engine. Specially at the temperatures (89 -108) you are 
stating. 


Your 1st prop was closer to what you need. Steve Bennett at Great Plains (VW 
Seller)  basically said you need about 2900 rpm static to be sure you were 
good.  The RPM will climb up once you are in the air and moving.


I'm running a VW (Revmaster 2100D) and a 1500 ft roll to get 65 mph at 5500 ft 
is actually good in my opinion. I know I used up quite a bit more on a trip 
from the Midwest USA to California over some serious mountains in 2014. There 
were a couple airports I landed/took off at with elevations over 5500 ft. But 
my empty weight is closer to 650 pounds. My best climb rate was maybe 300-400 
ft/min at those elevations. I do normally get about 800 fpm climb at my home 
airport in Missouri (1000 ft MSL).


Options, 1st I'd go back to the 1st Prop and Carb set up. That was close. I 
believe someone else already commented that increasing the length to 54" was a 
bad idea - that is correct. Normally, you shorten the prop to increase RPMs.  
Lowering the pitch usually helps as well with increasing the rpm, but length is 
a factor as well. 


Also,


1. Can you relocate to a lower elevation for initial testing?
2. Wait for cooler weather?




Rob Schmitt
N1852Z
www.robert7721.com




-Original Message-
From: PIERRE via KRnet 
To: krnet 
Cc: PIERRE 
Sent: Wed, Dec 23, 2015 2:37 am
Subject: KR> VW + Prop

Hi Guys,



It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on my KR2S
(haven't flown yet). The max revs I got was 2,760rpm static.



I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm, but I
only got to 1,850rpm. Stripped the 2 Stromberg 175 cd carburetors and had
them rebuilt - no difference. The main problem with these numbers is that I
can only get to 65mph IAS and it takes 1,500 feet to get to that speed. The
main reason for wanting 3,000rpm is that the vw max torque is at 3,000rpm
and I think I will then jump to heigher rpm and thus more thrust and then
higher speeds.. What am I missing?



The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the cabin,
weight is 876lbs empty, so she is a bit heavier that she should be. (I am
176lbs and 5ft 8in) My altitude is 5,500feet ASL and the temps we had is
between 89 degrees and 108 degrees Fahrenheit. (32 degrees - 42 degrees
centigrade)



Hope somebody can help!



Cheers,

Pierre

___
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options

KR> VW + Prop

[Mark Langford]

I wrote:

 >I can turn 3200 rpm static and turn it up to 2450 or so
 > wide open with a 2180cc engine with 8.6:1 compression ratio and 30
 > degrees of advance at wide open throttle.

Obviously, top RPM is 3450 or so, not 2450 or so.  Also, I should 
mention that I'm now flying a "52x54" Sterba prop on the 650 pound KR2. 
  As the engine gets broken in, I expect the RPMs to come up a bit more 
also, maybe 3500 or so.  And yes, shortening the 48x52 prop may get you 
there, but I'd still make absolutely sure that engine was putting out 
peak power before I took to the sky.  Best to get all of this done while 
this winter, while climb rates and engine cooling are good.

I do agree that a Type 1 VW on a heavy KR2S is not advisable, and when 
you throw in high temperatures and high density altitudes, it may be a 
"winter-only" airplane.  My experience with the Type 1 is that it's 
"cooling challenged" when compared to the Corvair, mainly because head 
fin area is very limited.

Mark Langford
ML at N56ML.com
http://www.n56ml.com

KR> VW + Prop

[Mark Langford]

Pierre wrote:

>> It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on
my KR2S> (haven't flown yet). The max revs I got was 2,760rpm static.<<

Depending on the displacement of the VW engine, you likely need less 
pitch (as others were quick to point out).  The way the prop maker 
measures pitch is important also.  Having had about 20 different props 
on my KR2S and KR2, I can tell you that the pitch numbers vary wildly, 
with respect to RPM.  Sterba, for example is almost always has higher 
pitch numbers for a prop that would turn the same RPM from somebody 
else.  Tennessee props tends to be nearer to Sterba than others.

If you haven't seen it already, take a look at the prop vs engine 
numbers listed for fifty different KRs at
http://www.krnet.org/kr-info.html .  That may help you narrow it down.

Another issue is are you sure the ignition timing is correct?  It's 
worth double checking everything involved in making that right (TDC 
mark, for example). Ignition timing is everything.  Checked at 2700 rpm 
or above for full advance to 30 degrees? That eliminates advance issues. 
I know it's a real pain to check timing with a a propeller installed, 
and very dangerous, so I've started doing it before the prop is even 
installed. Given that I do have a flywheel on the back of the engine for 
the starter and alternator, it's not going to hurt the engine for a few 
minutes, and it allows precise setting of the timing without the 
adventure of a prop being there.  What a huge difference in pucker factor!

And you know for a fact that the cam timing is dead on?  Have you 
considered having the 48x52 repitched to something a little less?  At 
least that way you have two data points.

As a data point, I can turn 3200 rpm static and turn it up to 2450 or so 
wide open with a 2180cc engine with 8.6:1 compression ratio and 30 
degrees of advance at wide open throttle.  I would be reluctant to take 
off with only 3000 rpm with my short runway.

Mark Langford
ML at N56ML.com
http://www.n56ml.com

KR> VW + Prop

[Dan Heath]

If you want a good engine for that heavy KR, I have a Roy Szarafinski
Corvair complete except for the exhaust.  I mean complete with Ellison, prop
and spinner.  I will throw in the slightly damaged cowling as well.  I want
a bigger engine for my Panther.



You can contact me at Danrh at Windstream.net



See N64KR at  <http://krbuilder.org/> http://KRBuilder.org - Then click on
the pics 



2015 KR Gathering - McMinnville, OR.  September 3 - 6 -- See U There.



Peoples Choice at 2013 - KR Gathering in Mt. Vernon, Il - MVN 

Best KR at 2013 - KR Gathering in Mt. Vernon, Il - MVN 

Best Interior at 2013 - KR Gathering in Mt. Vernon, Il - MVN 

Best Paint at 2013 - KR Gathering in Mt. Vernon, Il - MVN 

Best Firwwall Forward at 2013 - KR Gathering in Mt. Vernon, Il - MVN 



Best Interior and Panel at 2008 - KR Gathering in Mt. Vernon, Il - MVN





Daniel R. Heath - Lexington, SC





-Original Message-
From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Tony King via
KRnet
Sent: Wednesday, December 23, 2015 6:03 AM
To: KRnet
Cc: Tony King
Subject: Re: KR> VW + Prop



At 876 lbs empty I'd be looking for a bigger engine than a VW - especially
at that altitude and with those temps.  Also, I'm pretty sure 3,000 rpm is a
bit low - most of the VW guys seem to go for around 3,400 - 3,600.



TK



Sent from my iPad



> On 23 Dec 2015, at 6:36 PM, PIERRE via KRnet <
<mailto:krnet at list.krnet.org> krnet at list.krnet.org> wrote:

> 

> Hi Guys,

> 

> 

> 

> It feels as if I've hit a brick wall. I had a 48(pitch) X 52 prop on 

> my KR2S (haven't flown yet). The max revs I got was 2,760rpm static.

> 

> 

> 

> I then bought a 45(pitch) X 54 prop to see if I can get to 3,000rpm, 

> but I only got to 1,850rpm. Stripped the 2 Stromberg 175 cd 

> carburetors and had them rebuilt - no difference. The main problem 

> with these numbers is that I can only get to 65mph IAS and it takes 

> 1,500 feet to get to that speed. The main reason for wanting 3,000rpm 

> is that the vw max torque is at 3,000rpm and I think I will then jump 

> to heigher rpm and thus more thrust and then higher speeds.. What am I
missing?

> 

> 

> 

> The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the 

> cabin, weight is 876lbs empty, so she is a bit heavier that she should 

> be. (I am 176lbs and 5ft 8in) My altitude is 5,500feet ASL and the 

> temps we had is between 89 degrees and 108 degrees Fahrenheit. (32 

> degrees - 42 degrees

> centigrade)

> 

> 

> 

> Hope somebody can help!

> 

> 

> 

> Cheers,

> 

> Pierre

> 

> ___

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KR> VW + Prop

[Adam]

Adam Tippin
A&P KR2S builder
What engine do you have?
It seems you decreased pitched and at the same time increased length.  
Increasing length, decreases RPM with the same rated horsepower. 
Similarly decreasing pitch, increases RPM. 
Shorten the either of the props and you will see a significant increase in RPM. 

> 
> 
> 
> The KR2S has got wing tanks and tri-cycle gear and is 4" wider in the cabin,
> weight is 876lbs empty, so she is a bit heavier that she should be. (I am
> 176lbs and 5ft 8in) My altitude is 5,500feet ASL and the temps we had is
> between 89 degrees and 108 degrees Fahrenheit. (32 degrees - 42 degrees
> centigrade)
> 
> 
> 
> Hope somebody can help!
> 
> 
> 
> Cheers,
> 
> Pierre
> 
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
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> options

KR> VW Prop

[Dan Heath]

Dave,

You could benefit from consulting with a prop maker.  Ed Sterba makes many
of the props used on VW engines.

ed_ste...@excite.com


See N64KR at http://KRBuilder.org - Then click on the pics 
See you at the 2012 - KR Gathering in Mt. Vernon, Il – MVN – 40th
Anniversary
There is a time for building and it is over.
Daniel R. Heath - Lexington, SC

-Original Message-


1) Is repairing such a crack safe/economical, and if so, how does one go 
about doing it?

KR> VW Prop

[Ronald Wright]

Chrissi,

There is a link in the email below about how to
determine what pitch/diameter prop is needed.. 
Thought you might like to read it when time permits. 
I have not been in the site but will later tonight.

Ron

Another email coming with Cowling Photos..  Cannot
remember if I sent them to you or not.. Still have to
find out what it is for??  I think it is a Sonerai.



> You should remember that diameter and pitch are only
> 2 parameters to 
> affect prop performance.
> 
> The prop pitch just tells you the maximum
> theoretical air speed  the 
> prop can pull at  given revs - it doesn't tell you
> how much oomph you 
> need to spin it.
> 
> If you want to investigate the perfect prop for your
> set of 
> circumstance, have a look at 
> http://www.mh-aerotools.de/airfoils/javaprop.htm
> 
> You can use the gadget to size the prop to suit your
> own requirements, 
> the only problem is there ain't anyone out there who
> will offer you an 
> off the shelf prop to perfectly match your
> specification, but it will at 
> least allow you to ask the correct questions and
> pick a prop that is 
> gonna get close to what you want.
>