From: "Nat Puffer" <cozy@extremezone.com>
Subject: Re: COZY: Prop Question?
Date: Fri, 1 Jan 1999 12:34:33 -0600

Dear Eric,
The 180 and 200 hp Lycomings are at the extreme limit of the amount of
horsepower which can be transmitted from a 7" diameter flange to a wooden
propellor by friction (I have been told by more than one source). All the
wooden propellors I have seen for a 7" diameter flange have at least a
7-1/2" hub. When you apply the amount of torque on the bolts required to
provide the friction necessary, you are on the verge of crushing the wood,
even when the prop hub is 7-1/2" in diameter. I don't know whose propellor
you purchased (and you don't have to tell me), but I don't think much of
the designer/manufacturer if he said it's okay for a 200 hp 4-cylinder
engine. He has used up a significant amount of the safety factor you are
entitled to. I suggest you tell him the designer of your airframe states
that his propellor isn't satisfactory and you should ask for you money
back. I have an extra propellor I could loan you if this causes you a bind.
 Clark Lydick is in the same building as Judy Sabor. Why don't you get his
opinion as well? I don't like to see anyone putting one of my builders at
risk!
Best regards,
Nat

----------
> From: Eric Westland <ewestland@altavista.net>
> To: canard-aviators@canard.com; Cozy Builders <cozy_builders@canard.com>
> Subject: COZY: Prop Question?
> Date: Thursday, December 17, 1998 10:27 PM
> 
> Well, after waiting much longer than I should have, my 2-blade prop
> showed up for my Lycoming 200 hp engine.  It looks just fine, but when I
> went to mount it on my 7" extension from Judy Saber, I realized that the
> prop's hub was slightly undersize, 6.65" in diameter to be precise.  So
> I called the maker and he assured me this was OK.  I'm not so sure if
> it's OK or within the range of acceptability, what do you folks think?
> I guess I just figured it would be as large (or slightly larger) as the
> flange and crush plate surfaces.
> 
> 
> Thanks,
> 
> Eric Westland
> 

From: "Nat Puffer" <cozy@extremezone.com>
Subject: COZY: Hub diameter
Date: Sat, 2 Jan 1999 12:31:21 -0600

People,
Eric called and told me he checked with Clark Lydick (Performance Props),
as I suggested, and Clark said a 6.6" hub diameter for a wooden propellor
on a 200 hp 4-cylinder Lycoming is okay. This really surprises me, but I
respect Clark's opinion. However, for myself, I will insist on a 7.5"
diameter hub. I consider wood shavings on the floor in the same category as
altitude above you and runway behind you.
Best regards,
Nat 

From: cdenk@ix.netcom.com
Date: Fri, 22 Jan 1999 16:53:31 -0600 (CST)
Subject: COZY: Fwd: prop flange size versus horsepower

The following is from Steve Boser, Sensenich Wood Propeller Co. engineer. He has prepared it for 
this group and asked that I forward it.



------Begin forward message-------------------------


To: "Carl Denk (E-mail)" <cdenk@ix.netcom.com>, <Jim_Agnew@IBM.NET>,
        "Nat Puffer (E-mail)" <cozy@extremezone.com>
Subject: prop flange size versus horsepower
Date: Fri, 22 Jan 1999 16:32:19 -0500

I've paraphrased some earlier sensenich documents regarding this subject,
and have added some specific notes regarding the Lycoming O-320, O-360, and
spool spacers.


Drive-Torque Capacity of Crankshaft Flanges, 1999

Experience has shown that it is important to ensure that the drive-torque
capacity of a crankshaft flange / propeller hub is adequate.  Since only one
of the four strokes accomplished by a four stroke engine makes a positive
contribution to rated engine torque, the torque contribution by the engine
during the other three strokes is negative. It follows that the
instantaneous peak torque must be greater than rated engine torque.  The
ratio of instantaneous peak torque to rated torque will vary with the number
and arrangement of engine cylinders and the type of prop extension, among
other things.

Most common flanges designed to drive wood propellers can be idealized into
two distinct torque-transmission systems.  The flat hub face can be thought
of as driven by static friction or the propeller can be considered as driven
by the drive-bushings incorporated in the flange.  It is not possible to add
the drive-capacity of one system to that of the other.  If the propeller is
considered to be driven by static friction, the drive bushings will not feel
an imposed load and when the drive bushings experience a fluctuating torque
load, some movement of the hub against the flange must occur so that the
static-friction mechanism can not apply and scorching of the hub boss will
occur.

It is well known that the maximum friction force parallel to a contact face
is defined by the compression force perpendicular to that face multiplied by
a coefficient of friction dependent on the two materials in contact.  This
fact can be used to calculate the maximum resisting torque due to
compression of the wood propeller hub against the engine flange if the
compression stress in the hub and applicable friction coefficient are known.
Sensenich has derived an equation calculating maximum allowable peak torque
by static friction, with engine flange diameter being the single most
important factor.

If it is assumed that the drive bushings in the flange must bear the torque
load, then the maximum allowable peak torque equals the product of allowable
bearing stress for the drive bushings against the side of the holes provided
for them, the total drive bushing bearing area, and the drive bushing radius
from the crankshaft axis (equals bolt circle radius).

Calculations for both torque transmission systems reveal drive bushing
torque capacities at best only a quarter of static friction torque
capacities.  This is why maintaining proper bolt torque compression on the
wooden propeller hub is critical, since the drive bushings can only provide
a short term back-up.

Installations with satisfactory service histories indicate that the drive
torque capacity of that crankshaft flange is adequate.  It follows that the
instantaneous peak engine torque is less than the static-friction
drive-torque capacity of the flange.


One new factor in the last 20 years is the increased use of extensions or
spacers to move the propeller forward (or rearward) for more streamlining.
Any type of extension/spacer which moves the propeller off the crankshaft
flange will reduce the torsional rigidity of the crankshaft system and lower
the RPM at which torsional resonance can be excited.  Spool extensions in
particular** are torsionally "softer", which can cause the propeller to lag
behind and then race ahead of nominal engine RPM.  This lag/lead may appear
as increased peak torque at the propeller / engine interface.
Thus, a propeller mounted on a spool extension requires a larger drive
torque capacity than a direct installation on the same engine.

**Torsional stiffness of a shaft is directly proportional to the fourth
power of its diameter and inversely proportional to its length.



I will get together some tables with all the values when time becomes
available.
Below is a general rating of torque capacities:

ENGINE TYPE AND HORSEPOWER

EXTENSION TYPE / EXTENSION LENGTH / PROP CONTACT AREA WITH FLANGE / NOTES



Lycoming O-320 engine / 160 HP

stock engine flange / none / 6" diameter / satisfactory, no heavy aerobatics

spacer (solid extension) / 2-4" / 6" diameter / satisfactory, no heavy
aerobatics

spool / up to 4" / 6" diameter / satisfactory

spool / 4-6" / 6" diameter / marginal, especially for props with medium-high
mass moments of inertia

spool / 4-6" / 6.5"+ diameter / satisfactory

spool / +6" / 6"+ diameter /  unknown, test data not available


Lycoming O-360 engine / 200 HP

stock engine flange / none / 6" diameter / unsatisfactory

spacer (solid extension) / 2-4" / 6" diameter / unsatisfactory

spacer (solid extension) / .5-4" / 7" diameter / satisfactory, with drive
bushings for backup

spool / 4-6" / 6" diameter / unsatisfactory

spool / 4-6" / 6.5" diameter / marginal, no aerobatics or high mass moment
of inertia props

spool / 4-6" / 7.0"+ diameter / satisfactory
------End forward message---------------------------


From: cdenk@ix.netcom.com
Date: Wed, 10 Feb 1999 17:48:21 -0600 (CST)
Subject: COZY: Prop info wanted - URGENT

For those flying with a 320 or 360 I could use the following info quickly:
Engine:
Prop Manufacture:
Aluminum prop hub diameter
Bolt Dia.
Prop material Birch or Maple
Approx. lamination thickness (thin, 0.3", or 3/4")
Normal bolt torque you use:
Prop wood hub diameter
Any problems with mounting installation (bolt torque, etc)
Mounting face condition (any evidence of movement at perimeter)

Quicker is better than being very accurate, indicate where your memory wasn't super.

Thanks.....

Date: Fri, 12 Feb 1999 20:16:08 -0500
From: Gary Dwinal <gdwinal@exploremaine.com>
Subject: COZY: Catto Props

Hi Folks,
   I have recently purchased a Catto three bladed prop from a fellow who
decided not to complete his Cozy MKIV.  I would like to contact Catto
but have no phone number or e-mail address.  Is there anyone who can
help me out with one or both of these.  BTW - I have successfully fitted
a Hal Hunt  4 pipe, in-cowl exhaust system under the cowl of my
AeroCanard with a very minor cowl mod and slight pipe mod.  The
AeroCanard cowlings are nearly identical to the Velocity cowlings, so
I'm sure this would be very easy to do on a Velocity as well.  It should
result in a noted reduction in drag in not having the large exhaust
fairings hanging down under my cowling.  Are there any other 4-place
canards that have the 4 pipe, in-cowl system.
Gary Dwinal

From: "DL Davis" <dldavis@erols.com>
Subject: RE: COZY: Performance or Catto
Date: Thu, 11 Mar 1999 06:56:51 -0500

One of the biggest advocates for the Performance three-blade has been Ken
Miller.  He praised them endlessly, and convinced quite a few other builders
to go for it (me included).  But now, with a series of incidents involving
cracks and blade failures in the Performance prop, plus the extraordinary
price difference, even Ken Miller has switched to Catto.  He sent some email
recently to all his three-blade disciples explaining his decision.  The
Catto three-blade has a fiberglass surface over the wood core.  MIGHT be
less prone to cracking.  It certainly is less expensive.  Several people
that have tried them, report good performance.
Dewey Davis

> -----Original Message-----
> From: owner-cozy_builders@betaweb.com
> [mailto:owner-cozy_builders@betaweb.com]On Behalf Of marcna
> Sent: Wednesday, March 10, 1999 10:09 PM
> To: Cozy Builders Group
> Subject: COZY: Performance or Catto
>
>
> I'm getting ready to order the Propeller for a Cozy MKIV and called
> Performance Propeller about a June delivery and was told that the
> three blade goes for $2150.  I remembered reading a recent Cozy
> newsletter about Catto who was also selling props for the Cozy.   I
> called and got a quote for $1200 for the Catto 3 blade prop.  I know
> that Performance makes a good product, does anyone have any experience
> with Catto?  The price is very good.
>
> Marc Parmelee
> Cozy N425CZ
>

From: cdenk@ix.netcom.com
Date: Thu, 11 Mar 1999 17:06:11 -0600 (CST)
Subject: RE: COZY: Performance or Catto

I have had 2 performance props that split about midchord from the tip that were repaired by 
gluing the crack and wrapping the tip with BID @45 degreesa and UNI strong axis perpendicular to 
length of the blade. Both fiberglasses were about 3" from the tip. Both damages were from debris 
picked off the tarmack.

The current prop (which is an experimental, experimental I'm testing for Sensenich) was too 
flexible and had vibration problems without glass. It now has 2 plys of BID at 45 degrees from 
tip to within 1" of the hub. One ply is considered sacrifical and is OK to sand through.

I had another prop (the best performing of the lot I have been testing, that picked up debris 
and split lengthwise at mid chord to within 10 inches of the crank centerline. The debris was 
small, and the prop scrap.

The prop I'm expecting any day now, will be the same design as the one above, and have the tips 
fiberglassed. This will become an extra charge item, along with urethane leading edge rain 
protection from Sensenich. With a little luck I will have that one at Sun N Fun. 

I would recommend the fiberglassed tips as added protection from splits caused by debris 
impacting near the tips. This will hopefully keep the prop from zipping a crack from a small 
impact at the wrong spot.

From: "Nat Puffer" <cozy@extremezone.com>
Subject: Re: COZY: Performance or Catto
Date: Thu, 11 Mar 1999 17:48:10 -0600

Gee, guys, I have been flying canard pushers since 1978 (21 years) starting
with a Varieze, and have used wooden props from at least 5 different
manufactures, and never split a prop. Am I doing something wrong?
Nat
----------
> From: cdenk@ix.netcom.com
> To: dldavis@erols.com; cozy_builders@canard.com
> Subject: RE: COZY: Performance or Catto
> Date: Thursday, March 11, 1999 5:06 PM
> 
> I have had 2 performance props that split about midchord from the tip
that were repaired by 
> gluing the crack and wrapping the tip with BID @45 degreesa and UNI
strong axis perpendicular to 
> length of the blade. Both fiberglasses were about 3" from the tip. Both
damages were from debris 
> picked off the tarmack.

Date: Fri, 19 Mar 1999 18:16:42 -0800
From: Randel & Nancy Livingood <doognivil@home.com>
Subject: COZY: Cato Props

Greetings all you airworthy canard flyers and builders,

I have a question for you.  I have been trying to do some research about
propellors and thought that I might be interested in getting a three bladed
prop.  I saw some folks talking about Cato props and wondered if anyone has
the address or phone number or web page where I could contact them?

Any help will be put to good use.

Regards,

Randel Livingood
Cozy Mark IV -- N727RN (Reserved)

http://www.members.home.net/doognivil/index.html

Date: Sat, 20 Mar 1999 09:43:36 -0500
From: Gary Dwinal <gdwinal@exploremaine.com>
Subject: Re: COZY: Cato Props

Hi Randel,
   You can contact Craig Catto at      craigcatto@hotmail.com    or call him at
209-754-3553.      He builds very nice stuff.
Gary Dwinal

Randel & Nancy Livingood wrote:

> I saw some folks talking about Cato props and wondered if anyone has
> the address or phone number or web page where I could contact them?
>



Date: Wed, 24 Mar 1999 19:25:08 -0800
From: marcna <marcna@concentric.net>
Subject: COZY: Mail for Wilcott

I recived this email from Chuck Wilcott and am passint it along to the
group.

Hi Marc and Nadine - The picture of your airplane in the
latest Newsletter looks great!  Maybe you are already flying
by now.

I'm really responding to your request for Catto Prop
information.  I have been flying with one of his 3 blade
props on my Cozy since new.  I started with his 6481.  That
was too much pitch.  Never got more than 2450 rpms with
that.  Then went to his 6480, which I am running now.  Rpm's
still a little low, max at 2600 (static @ 2340).  If I were
to order another for my 180 hp Lycoming, I might kick the
pitch down another inch, but you could discuss that with
him.  He is very good to work with.  He let me use a loaner
prop while I was waiting for the second one to be built.  I
just don't think I am developing full horsepower at less
than rated rpm.

The prop has "weathered" fine.  About 250 total flight hours
on it.  It has a few rock dings, but overall looks OK.  I do
have one comment on the finish.  I had the prop painted
again, to match the grey stripe on my plane.  In the last 50
or so hours, I have noticed some very small cracks in the
paint.  I looked at these very closely, and have had these
inspected by other, more knowledgeable, people.  Their
opinion is the same as what I concluded.  The cracks are
only from the paint flexing, and probably don't extend into
the fiberglass covering.
All this said...would I purchase another from him...YES.

>From the introductory comments in the Newsletter, it appears
as this was a thread from the Internet group.  I removed
myself from the list several years ago, so I was NOT aware
of your interest.  If you would like to put the remarks
above on the Internet, go ahead.

Chuck Wolcott
Cozy Mark IV #154
(been flying for 4 1/2 years now)
chuckw@qnet.com



From: cdenk@ix.netcom.com
Date: Sun, 25 Apr 1999 18:37:30 -0500 (CDT)
Subject: COZY: Hershey Kiss spinners

At Sun N Fun, someone commented my spinner was wobbling, not having equipment to check it there, and being conservative, I 
removed the spinner, leaving the bulkhead and fairing in place. Coincidental the Prop bolts had loosened a bit (not near 
enough to be dangerous) more than I would have expected. Prop bolts do, on occasion need checking while at a distant 
airport and setting the tracking of the spinner is difficult, if not possible with the luggage space available. Someone 
recently had a method of using small alignment holes, which I am going to try, but the thought of using a smaller spinner, 
where tracking was not an issue is being considered. Then I felt that good data on the possible benefits of the Kiss 
spinner became an interest.

This morning I flew 3 test flights with kiss spinner, spinner removed but bulkhead and fairing in place, and finally 
nothing but the prop bolted to the extension.

Spinner assembly: Lightspeed engineering spinner, composite backing plate made from Ken Miller's mold, and Spruce AC-1 
fairing

Aircraft Loading: 190 lbs pilot, 150 lbs. sand other front seat, 52 gallons fuel at start, about 10 gallons used.

Note: prop is too flat pitch for this low altitude, low manifold pressure to prevent overspeeding engine.

Flight: 3000' MSL with altimeter set to 29.92", 23.5" manifold pressure, lean for maximum RPM (very little leaning 
required), flight over Lake Erie with smooth air and very little if any thermals, same basic route.

Equipment	outside	CAS		TAS		RPM	Manifold Pressure	
      	Air (F)							Inches

With Spinner 		43	167K	174K		2680		23.5
With Bulkhead& Fairing	45	163K	170K		2640		23.5
No Bulkhead or Fairing	47	162K	169K		2630		23.5

I consider the airspeed numbers plus or minus 1K accuracy, the manifold pressure and RPM are JPI slimline digital. I 
believe that the spinner with fairing a reasonable claim would be 5 knot increase at low altitudes. Note that for more 
accuracy, data should be collected at different altitudes and temperatures. 

It is difficult to align the kiss spinners, they need reinforcement after cutting the prop blade holes, and then should be 
balanced. I tried static balance of the components, it was nearly impossible, and maybe I did more harm than good. This 
area need attention. Maybe someone need to tool up to do the reinforcement and balancing.

Any thoughts?

From: "Nat Puffer" <cozy@extremezone.com>
Subject: COZY: Sensenich propellors.
Date: Fri, 21 May 1999 16:04:38 -0500

Dear Builders,
As you may or may not know, I have been flying a 64 x 76 3-blade
Performance prop for almost 7 years now, which I purchased because of good
reports from others who had purchased 3-blade Performance props. I even
purchased a spare, which I have just recently tried out. In the meantime,
Sensenich wanted me to try one of their 2-blade wood props (70 inch
diameter). After a number of delays, I finally put it on, and when I ran it
up on the ground, only got 2150 rpm, so I decided not to fly it. But after
talking to Sensenich and Carl Denk, was talked into trying it. The first
time was without a spinner. It had good acceleration, and after rotation,
turned up to 2350 in a 120 kt climb. I was beginning to like it, inspite of
the fact that it had more vibration than a 3-blade prop. I took down the
data at 5 different altitudes, and 5 different rpms. It was almost as good
as my Performance. So then I made a spinner and air flow guide for it and
tried it again. At each rpm, it was anywhere from 1 to 4 kts. faster with
the spinner than without, and with the spinner, I got it to turn up to 2650
rpm at 8,000' for a TAS or 218 mph, which was somewhat better than my new
Performance. So my conclusions are these:
The Performance 3-blade is a good prop, very smooth, but expensive.
The Sensenich 2-blade has more vibration than the Performance, might be 1
or 2 kts faster, is a lot cheaper, and looks to be very husky. I don't know
how much the Sensenich costs, because I haven't agreed to buy it yet. Hope
this helps.
Nat

From: cdenk@ix.netcom.com
Date: Fri, 21 May 1999 19:57:08 -0500 (CDT)
Subject: Re: COZY: Sensenich propellors.

Nat questions price?
First I want to qualify my position with respect to Sensenich Wood Propeller Co. as someone has recently suggested: I was 
promised a propeller at no cost for flight testing 2 or 3 props to determine the drag of a Cozy with a Lycoming 320 160 Hp. 
engine. I was to provide test data on all the props. THe Sensenich engineer spent 2 nights at my home, while we got started 
testing, to make sure I provided meaningful accurate data. He flew as passenger, recording data for the first flight which was 
a Performance Prop. All other flights were made with the engineer replaced with 150 lbs of sand bags. To date I have done more 
than a dozen flight tests, each one reaching 12,000 feet, and lasting about 1:40. I have data on various prop designs, effect 
of paint ridges near the leading edges, sand the blades with 600 grit sandpaper, with and without spinners, minimum blade 
thickness. I have laid up BID on a prop that fluttered, and then flown it for many hours. The regulars at my airport know me a 
the guy carrying a prop in or out. The effort and cash expended at this point far exceeds the cost of a prop, but I have 
continued in a effort to find safe props for the rest of us. There is no other agreement between Sensenich and myself beyond 
this. I do not, nor in the future receive a commission or ther compensation for a prop sold. At this point all the props have 
been received with paperwork indicating for evaluation, and officially have not been titled to me.

At this point excuse if I stretch the rules slightly, and then I'll try to remain quiet on the subject. For a 320 in a Cozy 
the price (the last I heard) with urethane leading edges was $755  US, and for a 360 was $795 US. I would suggest adding the 
fiberglass on the tips for additional protection from splitting from debris hitting the tip. Since I have the only one like 
this they have made, I don't know the additional cost. The props are made exactly the same materials and processes as their 
certified props.

If anyone has interest, feel free to contact me privately.
 

From: "Nat Puffer" <cozy@extremezone.com>
Subject: COZY: Sensenich propellor
Date: Sat, 22 May 1999 13:36:25 -0500

Builders,
I would like to pass on a couple of things that I learned in my propellor
testing:
1) You cannot rely only on static rpm. With some props, like Performance,
the rpm changes only slightly from static to climb at 120 kts. From 2390 to
2420, for example.
With other props, like Sensenich, the rpm can change substantially from
static to rotation and climb at 120 kts. From 2150 to 2350, for example.
There is probably a reason, but I can't tell you what it is. So you really
need to get flight data.
2) It is very difficult to hold altitude and rpm steady long enough for the
airspeed to stabilize, so you need a lot of data points. Four different
rpms and 5 different altitudes, for example, to give 20 data points. Some
points will be obviously out of line, so you hope the average of 20 points
will be closer to the truth.
3) The average of 20 points for the Sensenich prop with a 10-1/4" dia
spinner was 2.7mph faster than the average for the same prop without a
spinner. I don't remember how to calculate the standard deviation, but I
think the 2.7 mph figure is significantly different.
4) The other indication that a spinner reduces drag was that at full
throttle my Lycoming turned 50 to 60 rpm faster with the spinner, and the
top speed was 7 to 8 mph faster with the spinner than without. So, at the
same rpm the spinner gave me 2.7 mph faster, but at full throttle, the
spinner produced more rpm and even more speed. 
5) Another interesting finding was that at the same altitudes and rpms, the
Sensenich and Performance (both with spinners) gave essentially the same
performance. Below 2400 rpm, the Performance was slightly better, and above
2400 rpm the Sensenich was slightly better, so they averaged out the same.
However, at full throttle at altitude, the Sensenich turned about 50 rpm
more than the Performance, and at the higher rpm, produced 6 to 8 more mph.
I think this means the Sensenich 2-blade is slightly more efficient than a
3-blade. According to my FBO, this is usually the case.
Hope this is interesting to you.
Nat 

From: cdenk@ix.netcom.com
Date: Sun, 23 May 1999 07:45:57 -0500 (CDT)
Subject: Re: COZY: Sensenich propellor

Nat said: <Below 2400 rpm, the Performance was slightly better, and above
2400 rpm the Sensenich was slightly better, so they averaged out the same.>

3 Comments
1: One prop may be better at a given altitude and loading/C.G. than another. This fine tuning is why probably the first prop 
won't fit your flying style and airframe drag, and everyone is a little different, and I am talking changes that cruise would 
change several MPH. Since you should always have a spare prop at home ready to ship when you damage one, accurate data on the 
first prop, combined with a discusion with your prop builder should result in better performance for your conditions. With the 
first prop the discussion should include how you prefer to run your engine (cruise RPM/manifold pressure, altitude, 
temperature, etc.). For most operators, you really won't know some of this until you have some hours on the airframe since 
flying a Cozy is not the same style as say a Skyhawk. Many times you will cruise a higher altitudes, go further, longer time 
legs, etc.

2: The Sensenich prop Nat has been flying is the first MKIV with  a 360 engine prop Sensenich has built. The prop was computer 
designed, with the output transfered to a CNC (computer controlled) lathe that cut the wood blank to the exact shape of the 
prop including the cutout for the urethane leading edge. A craftsman, then sands and smooths ready for finish. The computer 
input for the aircraft was based on my Cosy flight tests for drag, adjusted for what was thought to be differences, and 
Lycoming engine power tables. It would be easy to duplicate or slightly adjust this prop by gluing up a blank, feeding the 
lathe the same or a new digital file. 

3: If anyone is near Plant City, Florida, just West of Lakeland, Sensenich does offer plant tours, call ahead to be sure 
someone is available.

Date: Sat, 22 May 1999 02:13:11 +0200
From: Jean-Jacques CLAUS <jjclaus@club-internet.fr>
Subject: Re: COZY: Sensenich propellor



Carl Denk wrote:

>  <The computer input for the aircraft was based on my Cosy flight tests for drag>

Carl and all,

Do you know what is the Cosy's drag found by sensenich ?

I'm using the D.BATES program to design my own propeller. The D.BATES program can compute an aircraft's drag by reverse
engeneering from flight and propeller datas.

Based on a COZY III datas I found a drag of 1.97 ( equivalent as a plate of 1.97 sq/ft ). My Cosy Classic is a bit wider and
longer than a COZY III so I would like to be more accurate.

Thank you,

Jean-Jacques CLAUS
FRANCE

ps: For those who are interrested I found a propeller manufacturer ( also COZY III owner ) who
can use the D.BATES's output to make your 'best' propeller ( wood + metal edge + glass + carbon tips ) on a CNC machine. Prices
are reasonnable ( $900 for a 2 blades, $2000 for a 4 blades ).



From: cdenk@ix.netcom.com
Date: Tue, 25 May 1999 21:59:47 -0500 (CDT)
Subject: Re: COZY: Sensenich propellor

On 05/22/99 02:13:11 you wrote:
>
>Do you know what is the Cosy's drag found by sensenich ?

No, I don't, I provided flight test data to Sensenich, they determined such numbers for their own computer program, and I 
assume that the info Sensenich determined is proprietory and confidential.

From: "Schuler, Larry" <Larry.Schuler@uscellular.com>
Subject: RE: COZY: Sensenich propellor
Date: Wed, 26 May 1999 08:11:00 -0500


>
>Do you know what is the Cosy's drag found by sensenich ?

Hmmmm.  CAFE should have the info for typical Cozy-IV.

Larry

From: extensionsystems@mindspring.com
Subject: COZY: Cozy Propeller Thrust
Date: Mon, 21 Jun 1999 14:37:56 -0500

Does any one know how much thrust the typical 180HP Cozy Propeller produces.

Thanks
Brian

From: "Nat Puffer" <cozy@extremezone.com>
Subject: Re: COZY: Cozy Propeller Thrust
Date: Sun, 27 Jun 1999 11:38:24 -0500

Builders,
400 lbs. for 180 horsepower sounds about right. We measured the thrust on
our 85 hp Varieze, and it was 200 lbs.
Regards,
Nat

----------
> From: Jean-Jacques CLAUS <jjclaus@club-internet.fr>
> To: extensionsystems@mindspring.com
> Cc: Cozy Group <cozy_builders@canard.com>
> Subject: Re: COZY: Cozy Propeller Thrust
> Date: Sunday, June 20, 1999 8:12 AM
> 
> extensionsystems@mindspring.com a crit:
> 
> > Does any one know how much thrust the typical 180HP Cozy Propeller
produces.
> >
> > Thanks
> > Brian
> 
> In some propeller design that I did with the Don BATES's program, the
> static
> thrust at 0 ft and 2400 rpm goes to approx 400 lbs.
> 
> Jean-Jacques CLAUS
> FRANCE
> 

From: cdenk@ix.netcom.com
Date: Sun, 27 Jun 1999 07:36:55 -0500 (CDT)
Subject: Re: COZY: Cozy Propeller Thrust

Was said <thrust at 0 ft and 2400 rpm goes to approx 400 lbs.>

I think most people cruise at 75% power, and with a prop that will give maximum TAS at 8000' (the altitude where full trottle 
= around 22.5" manifold pressure results in engine RPM redline, 2700 for a 320). Below this, and respecting the RPM redline, 
full trottle is not possible. THerefore at 0 feet, the trottle will be significantly closed with manifold pressure as low as 
23.5". The TAS will be possibly 8 knots less then the higher altitude. A 2" increase in pitch will bring that point where full 
trottle can be reached without overspeeding the engine down around 7000' I have one 84" pitch prop that I can use full trottle 
above 12,000' gives 172K TAS (talking only cruise in level flight for this whole discussion), and a same design with 86" pitch 
gives 186K at 5000' full trottle, both respect 2700 RPM, and 25.5" manifold as an indicator of 75% power.

Date: Mon, 05 Jul 1999 23:12:21 -0400
From: Rob and Carla Kittler <rkck@mindspring.com>
Subject: COZY: prop selection

Was wondering whether ther might be a consensus among cozy builders/flyers
regarding the most suitable propeller. I'm not enamored with the
performance prop as recommended in the plans. Too many failures over the
years for my comfort.
I'd be most interested in input regarding some of the other types out there.

Thanks for you input everyone

Robert Kittler
SN 589
A year away (we hope)

Date: Sat, 10 Jul 1999 09:57:27 -0500
From: tazcat@zebra.net (Lori Cruger)
Subject: COZY: Prop extention

I'm about to order my prop extention and am trying to decide which
length to use. What is the advantage/disadvantage of the 8 inch compared
with the 6 inch extention?

I have purchased a Lycoming IO 360 for my engine. The air intake
interfears with the X part of the engine mount. I'm about to alter the X
to an H and was wondering if someone had the currect dementions to make
this change. Is there an alternative to cutting and welding my engine
mount?

What is my best option for installing the air filter?

Dan and Lori Cruger
#586  working on the fuel strakes

Date: Sat, 10 Jul 1999 20:24:57 -0400
From: "Marc J. Zeitlin" <marcz@ultranet.com>
Subject: Fwd: COZY: Prop extention

Lori Cruger writes;
>
>I'm about to order my prop extention and am trying to decide which
>length to use. What is the advantage/disadvantage of the 8 inch compared
>with the 6 inch extention?

My understanding is that the further back you put the prop, the less
interference with the airflow off the strakes/fuselage, and the more
efficient it can be.  Apparently it's less noisy, too.  I purchased the 8"
extension from Judy Saber, and it's a beauty.

The downside of the longer extension is that it has to be even more
concentric than the shorter one, as any imbalance will be magnified.  I
assume that this is one of the reasons for the higher cost (along with the
extra material).  I also got the larger crush plate (7", IIRC).

--
Marc J. Zeitlin           mailto:marcz@ultranet.com
                          http://www.ultranet.com/~marcz/

Date: Sun, 11 Jul 1999 21:20:08 -0400
From: Jeff Russell <JRaero@gte.net>
Subject: Re: COZY: Prop extention

David Domeier wrote:

> Dan and Lori,
>
>     You might check with Jeff Russell on the 8" extension.  I think they
> use it on the Aerocanard and I believe the Velocity goes with 8" also.

Correct :-)

--
Jeff Russell/AeroCad Inc.

From: "Richard  Goodwin" <richgoodwin@email.msn.com>
Subject: COZY: Prop Extensions 
Date: Sat, 17 Jul 1999 22:25:24 +0100

Cosy Classic, 0320 Lycoming.  What length prop extension, 6 or 8 inch?  If I
go for 8 inch should I be concerned about any extra loading on the
crankshaft under G?

Thanks for your help
Richard Goodwin



From: "Will Chorley" <anneandwill@worldnet.att.net>
Subject: Re: COZY: Prop Extensions 
Date: Sun, 18 Jul 1999 15:53:50 -0500

Depends on your engine mount but I have the Brock "Heavy" mount.  I bought a
6" at first after careful measurement, however, when I actually got
everything together it was too short so I exchanged it (and some more cash!)
for an 8", particularly with all the discussion about clearance between
cowling trailing edge and prop.  Moral - don't buy the extension until you
have the engine on its mount and the cowling jigged in position, then
measure.

By the way, I bought mine directly from Saber.  The lady at Saber is one of
those people you would like to do business with everyday and when you see
the quality of the parts you don't feel so bad about the cost!  (Bill
Bainbridge's 90 degree oil filter adapter is another example of superb
quality that you don't mind quite so much about paying for when you see it!)

Will



From: Robert Donatz <robert.donatz@precisionint.com>
Subject: COZY: Re: mufflers and noise
Date: Tue, 27 Jul 1999 09:10:06 -0700


John Slade wrote:
 but reducing the noise level by 50% or more would be worth a LOT of
trouble. So what am I missing? Why are there no mufflers on airplanes?

David Domeier wrote:
Why aren't they on our airplanes?  Probably 'cause they are dead weight,
reduce HP, and could come off and wipe out the prop.
dd

Jack Wilhelmson wrote:
>From a purely technical thing. A prop airplane's noise level cannot
appreciable be reduced by mufflers on the engine.  The prop is the noise
maker. Listen to a turbo prop fly over sometime.

Ok, guys. I know the topic isn't specific to Cozy building, but as long as
someone else brought it up I think I can justify posing my question. 

Has anyone had experience with the Felix Prop? To refresh some memories,
this was featured in EAA's Sport Aviation some time back (can't seem to find
that issue). If I remember the article correctly, this propeller was a
bi-cambered airfoil and had no appreciable affect on performance. However,
it did (reportedly) reduce prop noise. This prop was placed on several
aircraft and an everglades swamp boat. Since the noise reduction was
dramatic on the swamp boat (a pusher) and Cozy's are pushers (I know it's
thin, but that's my tie-in) I was wondering if anyone has tried this
propeller on a Cozy or any other airplane.  

Thanks,
Robert Donatz
Robert.donatz@precisionint.com <mailto:Robert.donatz@precisionint.com> 
Cozy Mk IV gonnabe (aka, Pre-build)

Date: Tue, 27 Jul 1999 13:49:07 -0500
From: David Domeier <david010@earthlink.net>
Subject: COZY: Felix Prop

Robert,

    re "Has anyone had experience with the Felix Prop?"

    All I can say is I talked to the Felix people at OSH last year and
if I had not already spent a bundle for the Performance Prop, I would
have tried theirs.  They appear to know their stuff, but I do not know
anyone running one.  They have been around for some time so I'm sure
their are people out there who can attest to their product.

dd

From: Todd Carrico <todd.carrico@aris.com>
Subject: RE: COZY: Felix Prop
Date: Tue, 27 Jul 1999 14:10:53 -0700


    re "Has anyone had experience with the Felix Prop?"

I saw bit on TV about a similar prop (if not the same).  It was originally
supposed to be a boat prop (in the water type, not air-boat), but someone
convinced him to try it on a plane.  The first time they tried it they
thought they had it pitched too steeply.  It was turning rated RPM, it was
just so much quieter.  I would like to know if any are flying behind
pushers.

tc

From: cdenk@ix.netcom.com
Date: Tue, 27 Jul 1999 17:08:52 -0500 (CDT)
Subject: Re: COZY: Felix Prop

As I understand, Nat has had excellent results with a Sensenich, that was the first one they made for a Cosy MKIV with a 360. 
I believe it is on his aircraft at OSH. The prop is made in every way like a certified prop, and could be if there is enough 
call for them.

From: "Alpha" <alpha@concordnc.com>
Subject: COZY: Felix prop
Date: Tue, 27 Jul 1999 18:59:55 -0400

From:Newsletter-Mirage Marathon, Celerity and other experimental homebuild
aircraft.
Volume 4, No. 6 - December 1998

I was just re-reading a magazine article by Fred Felix wherein he relates
the story of his development of a new, lower-noise and higher-thrust
propeller. (EAA's Sport Aviation magazine, November 1997)
In case you missed it, the Felix prop is REALLY different! It has a double
camber airfoil shape--in cross-section it's sort of like a dog bone with a
narrow part about mid way between the leading edge and the trailing edge.
Two cambered surfaces connected by a web, in other words.

Felix says his new, revolutionary prop design produces equivalent thrust
with less drag, and much less noise, than a conventional prop. It has been
tested on a Wittman Tailwind and on air boats with very good results.
But here is the really interesting part--Fred says that he drew his
inspiration from the invention of the compound bow with its pulleys and
several strings.

He was amazed that, after thousands of years of development and refining,
and at a time when a bow is no longer necessary to hunt game for meat, there
was still room for significant improvements, an opportunity that someone
fortunately seized.

The result is a bow that allows a "letoff" of tension when fully drawn,
resulting in more accurate shots for those of us who are not built like
Hercules. This breakthrough probably increased the number of participants in
sport archery by several orders of magnitude.

That observation led Felix to the conclusion that there were other common,
simple tools that might allow for improvement and so he began experimenting.

For him it began with a canoe paddle, another very simple tool which, like
the bow and arrow, has been around for thousands of years.

Mr. Felix is a canoe and kayak enthusiast, and after a great deal of
research and experimentation he invented that "better mouse trap," a more
efficient canoe paddle that happens to be double cambered.
Felix then figured that this technology might also be applicable to airplane
propellers. It is, and his double camber prop created quite a sensation when
first displayed at Oshkosh in 1997.
----------------------------------------------------------------------------
------------------------
Hopefully, we will soon have some info from someone who has tried one.

Jim Brewer
Albemarle, NC


From: cdenk@ix.netcom.com
Date: Tue, 27 Jul 1999 22:11:27 -0500 (CDT)
Subject: Re: COZY: Felix Prop

Welsh asked <Be interesting on what the price will be>

Last I heard: For a 320 - $755, For a 360 - $785 (I may be off by $10). These include the urethane leading edge. I would also 
recommend having the tips fiberglassed to minimize cracks zipping if debris catches the blade near the tip. I haven't heard 
the cost of the glass. Delivery usually is around 5 weeks. Would recommend converstion with Steve Boser, Sesenich engineer to 
include your flying style in selecting a pitch.

From: "Kyle Howard" <khoward@uwc.edu>
Subject: COZY: Mr. Brewer- Felix Prop
Date: Tue, 10 Aug 1999 12:58:31 -0500

Isaac Solomon is trying to send you this e-mail.


Dear Mr. Brewer,
	I have not done any scientific analysis of the performance of the two
props that I have used but here is my opinion for what it is worth.
	I started flying a little over six years ago with a Sterba prop. Ed Sterba
makes good props and the price was right ($350.) Only recently he has
raised the price just a little bit. The prop performed satisfactorily but
the static RPM was a bit high. I thought that I could trade some of that
for the top speed by getting it re-pitched. Since he lived only about 70
miles away I took it to him and he worked on it but I did not see any
significant difference in the performance. About that time Fred Felix
started to bring some of his experimental props to our airport for my
neighbor Jim Clement to try on his Tailwind for evaluation. Fred also lives
about an hours drive from here (Baraboo, WI.) Fred thought that he could
build a prop which would be more to my liking, and he did. I have been
using his prop for four years.
	This prop has a little more pitch than my Sterba prop. It has
SIGNIFICANTLY MORE blade area and it is much thicker. The static RPM is
considerably lower ( I do not want to give any numbers because I never
recorded the weather conditions etc.) It gives the same excellent climb
perfromance but I get a higher top speed with this prop. It is a well made
prop. I do not think that it is less noisy than other props.
Sincerely,
Isaac Solomon

Kyle Howard
Network Administrator
University of Wisconsin Washington County
(414) 335-5266

From: cdenk@ix.netcom.com
Date: Fri, 13 Aug 1999 15:53:24 -0500 (CDT)
Subject: Re: COZY: Mr. Brewer- Felix Prop

Give numbers!!! If you can handle an E-MAil attachment of an EXcel97 file, I'll send you a test flight form that will for your 
airframe allow accurate comparison. Really good, or such words don't tell us much. "Facts, just the Facts", the reader can 
make judgements.

From: "DeFord, Brian" <brian.deford@intel.com>
Subject: COZY: Chapter 23 - Sensenich Props
Date: Mon, 16 Aug 1999 09:05:29 -0700

I just ordered my prop from Don Rowell at Sensenich. This is the prop that
Nat recently reported on. The prop is a W70EM8L-89. It's 70" diameter, 89"
pitch which they recommend for standard operations on a 200hp O-360.
Delivery is about 4 weeks and the price less shipping is $840. When I flew
with Nat a couple of months ago in his MK-IV, he had the Sensenich prop on
and I was impressed. Based on Nat's data (and Carl Denk's as well) I
decideed to go with this prop.

Can you tell I'm getting excited???

Regards,
Brian DeFord
brian@deford.com

Date: Thu, 26 Aug 1999 12:17:15 -0700
From: hrogers@slac.stanford.edu (Howard Rogers)
Subject: COZY: MT Props


>FLYING JULY 1998
>COLBY FARMER Cozy MkIV converted  to AeroCanard 502-729-2076
>5731 TIMBERLANE PHILPOT,KY. 42366
>
>Colby started a MKIV and used most of our AeroCanard FG parts
>less the tub and main spar he built.  He has a MT prop and 200 hp
>and loves to give rides.  I have flown his airplane and it's a rocket
>at takeoff with the MT pushing it.  I wish I had  constant speed in the
>rear.  It makes takeoffs from 1500 to 2000 ft rolls to 500 to 700ft
>takeoff rolls.  Down side can be the aft CG from the prop weight.
>
>Give him a call to set up a demo.
>--
>Jeff Russell/AeroCad Inc.                    E-mail:   Jeff@aerocad.com


Jeff,
        I enjoyed hearing the comments about the MT prop.  I have a friend,
out here in Northern California (John McAvoy, Chech Jets) who is now
running an MT on his 0-320 powered Long EZ.  He said it adds nearly 1000
fpm to his climb rate, but I never got to hear what it did for his top
speed.  I am curious about two things (and cost almost doesn't come into
this).  How MUCH extra weight does this add, over a wooden prop?  How much
experience is there on running times and reliability with these props on
pushers?  It sort of sounds like a prayer answered, but I am always very
cautious in this particular area, considering how unfriendly these pushers
are in the prop environment.  Have you run accross many other MT's in
Canard service?  I'm sure we'd all love to hear more details about
something so potentially dramatic to our performance envelope.

Howard Rogers


From: "Nat Puffer" <cozy@extremezone.com>
Subject: Re: COZY: MT Props
Date: Thu, 26 Aug 1999 16:37:04 -0500



----------
> From: Howard Rogers <hrogers@slac.stanford.edu>
> To: cozy_builders@canard.com
> Subject: COZY: MT Props
> Date: Thursday, August 26, 1999 2:17 PM
> 
> 
> >
> 
> Jeff,
.  Have you run accross many other MT's in
> Canard service?  I'm sure we'd all love to hear more details about
> something so potentially dramatic to our performance envelope.
> 
> Howard Rogers
> 
> Dear Howard,
We have had two Cozy builders who installed MT or Hoffman props. The first
was Mike Marshall, an orthopedic surgeon who lived in Los Alamos, which had
a very high density airport. His Cozy performed very well, but after 2
years he had to send the MT back to Germany for an overhaul which was very
expensive. When he gave up his practice and took a teaching position in
Kansas (or Nebraska), he elected to go with a fixed pitch prop. 
The second builder was Tim Merrill, who won the Grand Champion award at
Oshkosh with his Cozy Mark IV in 1996 or 1997. He installed an MT (or
Hoffman?) prop because he was able to get a used one at a very low price
(they cost about $8,000 new). He used it on an 0-320, and got better take
off performance than we do with our 0-360, because he was able to develop
the full 160 hp for takeoff, whereas with an 0-360 and fixed pitch cruise
prop, we only develop about 135 or 140 hp for take off. 
When we designed the Cozy Mark IV, we recognized that the best takeoff
performance would be with an 0-320 and an MT or Hoffman prop, but the cost
and maintenance of that combination would be much greater than the 0-360
with a fixed pitch prop. Since most of our builders are cost conscious, we
decided to recommend the least expensive combination.
To answer your other question, the I0-360 weighs about 30 lbs or so more
than the 0-360, and the MT or Hoffman props also add a little weight, so
you do need more weight up front, and together, that increases the empty
weight. Although the constant speed prop helps you to lift more weight off
the ground, the down side is that it increases your rotation and landing
speed, as well as the complexity of the airplane, so we believe our
recommendations are safer for the average builder/pilot. Off field landings
can be dangerous. Kitplanes recently stated that over 60 mph, anything over
a smooth touchdown on a smooth surface, survival chances decrease rapidly.
That is why we preach building the airplane as light as possible.
Regards,
Nat

From: N11TE@aol.com
Date: Fri, 27 Aug 1999 00:54:02 EDT
Subject: Fwd: COZY: MT Props

 
Return-path: N11TE@aol.com
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Date: Fri, 27 Aug 1999 00:52:49 EDT
Subject: Re: COZY: MT Props
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In a message dated 8/26/99 2:21:20 PM Central Daylight Time, 
hrogers@slac.stanford.edu writes:

> Jeff,
>          I enjoyed hearing the comments about the MT prop.  I have a friend,
>  out here in Northern California (John McAvoy, Chech Jets) who is now
>  running an MT on his 0-320 powered Long EZ.  He said it adds nearly 1000
>  fpm to his climb rate, but I never got to hear what it did for his top
>  speed.  I am curious about two things (and cost almost doesn't come into
>  this).  How MUCH extra weight does this add, over a wooden prop?  How much
>  experience is there on running times and reliability with these props on
>  pushers?



Other than the two examples mentioned (Colby Farmer's AeroCanard with LIO-360 
and 3-blade MT prop and Tim Merrill's Cozy MKIV with O-320 and Hoffmann 
2-blade prop) I personally know of 3 other 4-place canards under final 
construction with constant-speed props.  I'm sure there are others I'm not 
aware of.

I have personally talked with both Colby and Tim and both told me that they 
were very happy with going to the CS prop.

My previous spam can had a constant-speed prop which I thoroughly enjoyed.  
It offered more flexibility and much more power on takeoff.  Therefore, this 
was one option I really wanted on my plane.  I calculated the additional 
weight at a little more than 15 lb. extra which I balanced by moving weight 
forward as I built.  

I originally priced an MT prop ... very well proven on many Velocity 
airframes (pushers).  When the original quote was substantial, I began to 
look for other alternatives.  I ran across Hoffmann Propellers and contacted 
the factory in Germany and became a dealer for them.

They have developed a special model for me for the 4-place pusher plane with 
a built-in 8 inch extension.  I received my own propeller last December.  I 
have also helped two other AeroCanard builders to order Hoffmann Propellers 
... one with a LIO-360 and one with a Franklin.

To date, none have flown, although one has had engine start.

I think the reliability of canard CS props has been shown to be good, 
although all CS props will be more expensive to operate than wood props.  
I've been told not to expect top end to be quite as high as a cruise fixed 
pitch prop.  However, with my plane having an IO-540, I'm not too concerned 
with this.  I do look forward to being able to run full manifold pressure at 
and above 7,500 ft and be able to reduce prop RPM to more comfortable levels.

Colby also told me it makes a great landing brake when you pull the power 
back.  If I'd known or thought about it I might have considered not 
installing the landing brake.  Although, one could make a case for keeping it 
for rock protection.

Tom Ellis
AeroCanard 540 s/n 11
From ???@??? Sun Aug 29 01:43:19 1999
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Subject: Re: Fwd: COZY: MT Props
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A concern of rear propellers is debris damage, 2 issues
1: In the event of a hit, what is the mode of failure. With wood prop 
blades, I highly recommend fiberglass wrapping of the tips to prevent 
zipper action of a split tip.

2: Rear props are much more prone to damage than tractor props. With the 
high initial cost, one should anticipate some damage, have a spare prop 
readily available and be prepared to spend $$$ to be flying again.

Date: Fri, 27 Aug 1999 19:19:25 -0700
From: "LCDR James D. Newman" <infaero@flash.net>
Subject: Re: Fwd: COZY: MT Props

Hi All,

> Carl Denk wrote:

> A concern of rear propellers is debris damage, . . .

> 2: Rear props are much more prone to damage than tractor props.

    If you widen your main gear, prop damage will not be any worse than with tractor props :-) .


Infinity's Forever,

            JD

From: "Nat Puffer" <cozy@extremezone.com>
Subject: COZY: Sensenich props
Date: Sat, 28 Aug 1999 13:33:39 -0500

Builders,
We have approved the Sensenich prop for Cozy Mark IV builders. We just
haven't zeroed in on the best specs for a 180 hp Lycoming. We tried 70" dia
x 87" pitch, and 69" dia x 87" pitch, and still couldn't squeeze out 2700
rpm at best power setting at altitude. 2640 rpm was the best we could do.
So we suggested Sensenich let us try a 70" dia x 85" pitch. We think this
will give us best climb and best cruise. Will let you know what results we
get. 
Best regards,
Nat

From: cdenk@ix.netcom.com
Date: Sat, 28 Aug 1999 07:37:49 -0500 (CDT)
Subject: Re: Fwd: COZY: MT Props

J.D. wrote <If you widen your main gear, prop damage will not be any worse than with tractor props 
:-)>

Not terribly scientific, but after I removed most of the thread from the nose tire, the light 
damage to the prop seemed to be reduced, I'm talking more the heavy sandblast type nicks. Also 
have on my to do list, new main wheel pants that shield the prop better. Big bucks and time are 
not available to install a retractable. First would be to build a Super Cyclone (Cessna 185 
clone), since our flying requirements are changing.


Date: Sun, 29 Aug 1999 14:43:50 -0700
From: "LCDR James D. Newman" <infaero@flash.net>
Subject: COZY: Re:  MT Props

Hi Carl and All,

> J.D. wrote <If you widen your main gear, prop damage will not be any worse than with tractor props
> :-)>

> Cark Denk wrote:
> Not terribly scientific, but after I removed most of the thread from the nose tire, the light
> damage to the prop seemed to be reduced, I'm talking more the heavy sandblast type nicks.

    Interesting.
    Installing a nose tire fender (Wes Gardner used to have a mold of this) would stop FOD from the
nose tire hitting the prop too.  Obviously, leaving the belly board out at all times, even on take-off
(for real dirty runways) if the runway is long enough and only until airborne (already been done),
would help stop FOD from the nose tire hitting the prop.

> Big bucks and time are not available to install a retractable.

    Just let me know when you are ready ;-) .

> First would be to build a Super Cyclone (Cessna 185
> clone), since our flying requirements are changing.

    I'll have to look up what that is.


Infinity's Forever,

        JD

Date: Sun, 26 Sep 1999 11:01:43 +0200
From: Rego and Noleen Burger <rnb@intekom.co.za>
Subject: COZY: Prop Specs

I would like all operators of two bladed props to please let me know
what dia and pitch you are running on Cozy 3 or 4 placers please.
Data gathereing to help me decide on prop.
State engine type and cruise @ 75% pwoer please.
Send direct to me if you feel it not of interest to the group.
-- 
Rego Burger
CZ4#139 South Africa 
Web:http://home.intekom.com/glen/rnb.htm 
Work e-mail, mailto:burgerr@telkom.co.za

From: cdenk@ix.netcom.com
Date: Sun, 26 Sep 1999 10:17:11 -0500 (CDT)
Subject: Re: COZY: Prop Specs

Prop diameter and pitch by itself doesn't say much. Each design family (manufacturer, airfoil crossection, and other items) 
can be compared within that family. But to say a 80x84 of a Sensenich, Performance, Cato, or whatever will have the same 
performance range doesn't work. In replying to Rego, include manufacturer, prop model, engine, airframe, and performance 
comments. Here;s mine

Cosy Classic, IO-320, 160 hp. Performance below is operating at 1831 lbs. takeoff weight.
Sensenich W67CML-84  Too flat pitch, Can't use full trottle till over 12,000' and not exceed 2700 RPM, 175K cruise 2000'- 
12,000'

Sensenich W67CML-86 Full trottle, 2700 rpm, 25.5" manifold @ 5000' 186 Knots cruise. Higher and lower altitudes, 175K+ cruise.

Date: Mon, 27 Sep 1999 12:41:20 -0700
From: "LCDR James D. Newman" <infaero@flash.net>
Subject: COZY: Re:  Whirlwind Props (was: "Runway Lengths")

> > WhirlWind's 20 lb. 3 blade constant speed prop is $6500.

> Howard Rogers wrote:
> JD, can you tell us where to get more info on the WhirlWind props?  Do they have a website?

    Yeap.   http://whirlwindpropellers.com   POC:  Jim Rust  (619) 562-3725

From: "Steve Campbell" <Campbell@ece.umn.edu>
Subject: Re: COZY: Whirlwind Props (was: "Runway Lengths")
Date: Mon, 27 Sep 1999 15:35:02 -0500

Just thought that you might like to know, I spoke to WW today.  They have no
products that they recommend for a canard pusher unless you are putting in a
O-540.
Steve Campbell
From ???@??? Mon Sep 27 06:43:34 1999
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Message-ID: <37EFE28F.5ED4EAA3@flash.net>
Date: Mon, 27 Sep 1999 14:33:03 -0700
From: "LCDR James D. Newman" <infaero@flash.net>
Organization: INFINITY Aerospace  (http://www.flash.net/~infaero)
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To: "Canards - 'R' - Us" <cozy_builders@canard.com>
Subject: COZY: Re:  Whirlwind Props (was: "Runway Lengths")
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Hi Steve and All,

> Just thought that you might like to know, I spoke to WW today.  They have no products that they
> recommend for a canard pusher unless you are putting in a
> O-540.

    While the above is basically correct, I just talked to Jim Rust of WhirlWind to clarify - they
will *eventually* be making pusher propellors.  But as of *today*, they have nothing to ship you
except a prop for the 0-540.
    They are 5 hangar rows over from me.  And like I've said before, I plan on using their prop.  So
I needed to know for myself their plans :-) .


Infinity's Forever,

            JD

Date: Sun, 31 Oct 1999 09:00:54 -0600
From: Curt Smith <csmith@siue.edu>
Subject: Re: COZY: Performance Prop performance

Dave,

I lost 50-75 rpm on the finished prop vs. the unfinished. Clark told me to
expect this. In my case, it was desired as I wanted to reduce cruise rpm by
just that amount.

My experience with engines is that even though they may be "broken in"
(rings seated so that oil consumption is nil and temps stable), they are
still "tight" for a long time. Mine now has about 150 SMOH and is running
better (faster, smoother) all the time. 

Knowing how thorough you are, you've probably already done this, but you
might check mag/ign timing.

Curt
LE N86CS

At 08:17 AM 10/31/99 -0600, David Domeier wrote:
>
>    Something weird is going on with my 3 blade Performance Prop.
>
>    Yesterday on take off, and this is not new, its been going on for
>some time, the rpm was 2400 most of the roll.  As soon as the airplane
>was airborne, rpm dropped to 2380.  The rpm usually hits peak as full
>throttle is reached but does not increase as speed is increased as one
>would expect with a fixed pitch prop.
>
>    I've done a number of full throttle runs 8500 pressure altitude
>recently and the engine numbers are about the same each time.  Max rpm
>is 2560.  A year ago the engine would turn at 2690.  TAS is off also.
>
>    Two things have changed in that time.
>
>    1.  The prop was new and unfinished.  It's been refinished by Clark
>Lydick.
>
>    2.  The engine has been overhauled with new cylinders.
>
>    Has anyone noticed a degradation in performance with a smooth finish
>as opposed to running an unfinished prop?
>
>    The engine has about 70 SOH.  I would think he cylinders would begin
>to be untight by now.  Maybe not.
>
>    What has been sitting in the back of my mind is the possibility of
>the blades flexing in some manner the is new as the prop ages.  They are
>mighty skinny.
>
>    What do you-all think?
>
>dd
> 




*****************************************************************
Curtis A. Smith, Ph.D.
Professor
Southern Illinois University at Edwardsville
Box 1125 
Edwardsville, IL 62026-1125

Phone: 618/650-3970
Fax:   618/650-3359

From: cdenk@ix.netcom.com
Date: Sun, 31 Oct 1999 12:41:53 -0500 (EST)
Subject: Re: COZY: Performance Prop performance

On 10/31/99 08:17:42 you wrote:
>
>
>   As soon as the airplane was airborne, rpm dropped to 2380. 

Common, the coarse pitch props needed for a Cozy's high speed cruise usually is partially stalled (a prop blade is an 
airfoil), and gets out of the stall during the takeoff run. To steck static RPM, do a second time at 180 degree heading 
change, average results.
>
1.  The prop was new and unfinished.  It's been refinished by Clark
>Lydick.

Also the urethane leading edges were installed, the leading edge profile may have changed slightly
>
>    2.  The engine has been overhauled with new cylinders.

Lots of items here, tight rings, ignition timing changed, a cylinder is bad performance (can happen anytime).
>
>    Has anyone noticed a degradation in performance with a smooth finish
>as opposed to running an unfinished prop?

Take a prop sand the blades with 600 grit sandpaper, loose 3 knots. With a paint thickness offset from masking ot end of 
urethane leading edge, loose 6 Knots.
>
>    The engine has about 70 SOH.  I would think he cylinders would begin
>to be untight by now.  Maybe not.

Should loosen within hours.
>
>    flexing in some manner the is new as the prop ages

Shouldn't.

How about the airframe, any changes there that could affect drag?
What about temperatures, and barometric pressure, use 29.92 for all data runs.



Date: Mon, 01 Nov 1999 08:28:44 -0600
From: Michael Pollock <michael.pollock@wcom.com>
Subject: RE: COZY: Performance Prop performance

David Domeier wrote:
>Something weird is going on with my 3 blade Performance Prop.


My performance prop does exactly the same thing.  However, I have had two of
them and both do the same thing.  They both go down in RPM as soon as I
lift-off or just a little before.  However, I can turn 2750 RPM at full
throttle at 8500 feet.  I believe this to be the quasi-constant speed nature
of the design.  What is your manifold pressure doing at climb, cruise, etc?
You also may not be delivering the same power as you were before due to the
cylinder change.


Michael.Pollock@wcom.com
Flying Velocity N173DT
Building Cozy MKIV #643



From: Militch@aol.com
Date: Mon, 1 Nov 1999 09:29:52 EST
Subject: Re:  COZY: Performance Prop performance


In a message dated 10/31/99 2:20:33 PM, david010@earthlink.net wrote:

>    Yesterday on take off, and this is not new, its been going on for
>some time, the rpm was 2400 most of the roll.  As soon as the airplan
<snip>

Funny you should ask. This response was explained to me at the Salisbury 
fly-in on Saturday. If I understood it correctly, before take-off, there is a 
lot of turbulence and cavitation behind the cowling area.  After take-off, 
with faster flow over the canopy, things clean up a bit, the prop loads up 
and you see a slow down.

Regards

Date: Tue, 02 Nov 1999 15:24:59 -0500
From: David A Froble <davef@tsoft-inc.com>
Subject: Re: [c-a] Re:  COZY: Performance Prop performance

While props are very complex things, you can apply some principals
to events at times to determine what's going on.  When a prop is
working, moving air, it requires energy to do this work.  This energy
is supplied by the engine.  Now consider a prop that is not doing work,
or is doing less work than usual, as in the case of a partially stalled
prop.  Since less work is done, less energy is required, and there is
more energy available to spin the prop faster.  I know it sounds wierd,
but it's good solid physics.  For an easy demonstration, take a common
window box fan.  notice the amount of air moved and the speed of the
fan.  Now cover the intake side of the fan to prevent air from being
drawn in.  Again note the air being moved by the fan (work) and the
speed of the fan.

Dave


Militch@aol.com wrote:
> 
> [The Canard Aviators's Mailing list]
> 
> In a message dated 10/31/99 2:20:33 PM, david010@earthlink.net wrote:
> 
> >    Yesterday on take off, and this is not new, its been going on for
> >some time, the rpm was 2400 most of the roll.  As soon as the airplan
> <snip>
> 
> Funny you should ask. This response was explained to me at the Salisbury
> fly-in on Saturday.
> 
> If I understood it correctly, before take-off, there is a lot of
> turbulence and cavitation behind the cowling area.  After take-off, with
> faster flow over the canopy, things clean up a bit, the prop loads up
> and you see a slow down.
> 
> Regards
> 
>                                                   \
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-- 
David Froble                       Tel: 724-529-0450
Dave Froble Enterprises, Inc.      Fax: 724-529-0596
170 Grimplin Road               E-Mail: davef@tsoft-inc.com
Vanderbilt, PA  15486

Date: Sun, 31 Oct 1999 16:22:00 -0600
From: David Domeier <david010@earthlink.net>
Subject: COZY: Re: [c-a] Performance Prop performance

Lynn,

    I had a Bruce Tift prop on my LEZ and wish he were still around.  I
liked that big beefy prop alot and if he were still around, I'd order
one for the Cozy just to have a spare and to compare numbers.

dd

From: "Lynn Crawford" <crawfordl@earthlink.net>
Subject: COZY: Re: [c-a] Performance Prop performance
Date: Sun, 31 Oct 1999 09:59:46 -0800

I have a 2 bladed Performance prop and see characteristics similar to what
you describe except that I saw these differences when I replaced my Great
American with the Performance prop.  My Performance prop is still in the as
built configuration (not finished yet) but it also acts like the prop
changes pitch for different conditions.  I can get the same static rpm as
with the Great American but at altitude full power, the RPM is about 150
maybe 200 RPM hundred lower.  My top speed is down from what it was but I
cruise at the same or slightly higher speed at at least 100 rpm slower.  I
think you are correct in assuming the blades flex and changes pitch with
airspeed and power.  Lastly my climb rpm is also slower than my ground
static RPM much as you describe.  The prop almost seems to have semi
constant speed prop characteristics.

From: "Nat Puffer" <cozy@extremezone.com>
Subject: Re: COZY: Re: [c-a] Performance Prop performance
Date: Sun, 31 Oct 1999 14:26:45 -0600

David,
Featherlite took over all the tooling from Bruce Tift's estate, and still
makes the same prop.
Nat
