Today's Message Index:
----------------------
1. 03:42 AM - Re: Kolb-List 2 strokes (Robert Schieck)
2. 03:44 AM - Re: Rotax lighting coil (GeoR38@aol.com)
3. 04:58 AM - 912S For Sale (John Russell)
4. 07:13 AM - Tail Weel Springs (Richard & Martha Neilsen)
5. 07:32 AM - Re: Tail Weel Springs (Cy Galley)
6. 07:37 AM - Re: Tail Weel Springs (John Hauck)
7. 08:00 AM - Re: Tail Weel Springs (Don Gherardini)
8. 08:43 AM - Re: Tail Weel Springs (Larry Cottrell)
9. 09:10 AM - Re: Tail Weel Springs (Bob Bean)
10. 09:12 AM - Re: Tail Wheel Springs (Richard Pike)
11. 09:13 AM - 2 sixtees or one 72 (Kirk Smith)
12. 10:19 AM - Re: 2 sixtees or one 72 (Don Gherardini)
13. 10:39 AM - Re: 912S For Sale ()
14. 02:05 PM - Preheating (Mike Pierzina)
15. 02:55 PM - Re: 2 sixtees or one 72 (Richard Swiderski)
16. 03:26 PM - Re: Trip (Larry Bourne)
17. 03:37 PM - Re: 2 sixtees or one 72 (Don Gherardini)
18. 04:03 PM - Re: Your application ()
19. 04:09 PM - EVO/AIR update (Paul Petty)
20. 04:10 PM - Re: 2 sixtees or one 72 (Richard Swiderski)
21. 05:40 PM - Re: Details ()
22. 05:46 PM - Re: Trip (Larry Bourne)
23. 06:03 PM - Re: 2 sixtees or one 72 (Kirk Smith)
24. 06:19 PM - Re: 2 sixtees or one 72 (Jack & Louise Hart)
25. 06:20 PM - Re: 2 sixtees or one 72 (Jack & Louise Hart)
26. 07:10 PM - Re: 2 sixtees or one 72 (Richard Pike)
27. 07:42 PM - Re: 2 sixtees or one 72 (BMWBikeCrz@aol.com)
28. 07:45 PM - Landing Gear Camber ??? (BMWBikeCrz@aol.com)
29. 08:44 PM - Re: 2 sixtees or one 72 (Don Gherardini)
30. 09:15 PM - Re: Landing Gear Camber ??? (Charles)
31. 09:46 PM - Re: 2 sixties or one 72 (Christopher J Armstrong)
Message 1
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| Subject: | Re: Kolb-List 2 strokes |
--> Kolb-List message posted by: Robert Schieck <rschieck@mers.com>
> --> Kolb-List message posted by: "Kirk Smith" <snuffy@usol.com>
>
> 1. The pilot is descending in a shallow descent at a relatively high airspeed
and
> throttle partially open (about half way or so). This is very dangerous setting,
Giant Snip
I already slayed this dragon, So here are some numbers:
582 with a GSC 3 Bladed 67 " prop
Static RPM on the Ground 5600 - 5700
Climb RPM (55 MPH) 5800 - 5900
WOT (88 MPH) 6400 - 6500
You can descend any way you want and the EGTs will not hit 1200 degrees.
The EGTs run between 1000 degrees and 1125 - 1150 degrees depending
upon what you are doing. I am contemplating reducing the size of the
main get to raise the EGTs.
keep smiling
Rob from Ontario
Message 2
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| Subject: | Re: Rotax lighting coil |
--> Kolb-List message posted by: GeoR38@aol.com
In a message dated 8/17/03 10:49:31 AM Eastern Daylight Time,
ulflyer@verizon.net writes:
> Has anybody seen a fuse block that mounts similar to a terminal strip that
> can hold say 1-5 automotive style fuses.
> jerb
>
Allen Bradley and other industrial control suppliers make them sold at
Electrical Industrial equipment distributors, usually only locals although Graybar
may have them also.
george Randolph
Firestar driver from Akron, home of Lebron James, soon to be Ocala Fla
Message 3
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--> Kolb-List message posted by: "John Russell" <jr@rometool.com>
Rotax 912S Engine Package, less than 150 hours.
1-912S Engine
1-Titan stainless exhaust
1-Rotax coolant radiator
1-Rotax oil cooler radiator
1-3-Blade Warp prop/72"
1-Custom machined 4" prop extention
1-EIS
1-Throttle cable assembly
1-Enrichment cables
1-Engine mount for Kolb
All for $10500.00
Currently mounted on a Slingshot
John Russell cell 706-506-3108
Message 4
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| Subject: | Tail Weel Springs |
--> Kolb-List message posted by: "Richard & Martha Neilsen" <NeilsenRM@comcast.net>
I have the optional full swivel tail wheel with the supplied tail wheel
springs. On my flight to Oshkosh I landed one time where the winds were
blowing 15-20mph on a black top runway. When I tried to turn cross wind the
tail wheel wouldn't turn. I had to stand on a wheel brake fairly hard. I
then had to taxi cross wind for almost a mile strait and I had to fully
deflect the rudder AND drag a wheel brake to taxi strait. I made a mental
note that when I got back I would order heaver compression springs for the
tail wheel.
When I was a Oshkosh I attended a forum where the speaker was saying that
their tail wheels are direct connected for better control. He said that tail
wheels controlled by springs are always lagging behind user input.
My question is should I just direct connect the tail wheel to the rudder or
use heaver springs?
Rick Neilsen
Redrive VW powered MKIIIc
Message 5
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| Subject: | Re: Tail Weel Springs |
--> Kolb-List message posted by: "Cy Galley" <cgalley@qcbc.org>
There must be a good reason why most all factory built tailwheels use spring
in their linkage and are not direct. It is probably lighter, and more
forgiving to landing with the tail wheel cocked. This gives to time to
recover so you don't shoot into the weeds.
Remember opinions are like noses... every one has their own and they always
pick theirs.
Cy Galley - Bellanca Champion Club
Newsletter Editor & EAA TC
www.bellanca-championclub.com
Actively supporting Aeroncas every day
Quarterly newsletters on time
Reasonable document reprints
1-518-731-6800
----- Original Message -----
From: "Richard & Martha Neilsen" <NeilsenRM@comcast.net>
Subject: Kolb-List: Tail Weel Springs
> --> Kolb-List message posted by: "Richard & Martha Neilsen"
<NeilsenRM@comcast.net>
>
> I have the optional full swivel tail wheel with the supplied tail wheel
> springs. On my flight to Oshkosh I landed one time where the winds were
> blowing 15-20mph on a black top runway. When I tried to turn cross wind
the
> tail wheel wouldn't turn. I had to stand on a wheel brake fairly hard. I
> then had to taxi cross wind for almost a mile strait and I had to fully
> deflect the rudder AND drag a wheel brake to taxi strait. I made a mental
> note that when I got back I would order heaver compression springs for the
> tail wheel.
>
> When I was a Oshkosh I attended a forum where the speaker was saying that
> their tail wheels are direct connected for better control. He said that
tail
> wheels controlled by springs are always lagging behind user input.
>
> My question is should I just direct connect the tail wheel to the rudder
or
> use heaver springs?
>
> Rick Neilsen
> Redrive VW powered MKIIIc
>
>
Message 6
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| Subject: | Re: Tail Weel Springs |
--> Kolb-List message posted by: John Hauck <jhauck@elmore.rr.com>
> I have the optional full swivel tail wheel with the supplied tail wheel
> springs. On my flight to Oshkosh I landed one time where the winds were
> blowing 15-20mph on a black top runway.
> My question is should I just direct connect the tail wheel to the rudder or
> use heaver springs?
>
> Rick Neilsen
Rick/Gang:
That's a lot of cross wind for any aircraft, most
especially a light plane like a MK III.
I personally would not use a direct link, on my
aircraft, from rudder horn to tail wheel horn. I
can envision a short life for rudder and possibly
the tail wheel.
I use compression springs supplied by Maule
Aircraft for their tail wheels, which I have also
used for many years on my MK III. However, I use
two of the smaller compression springs, rather
than one large and one small as supplied in their kit.
Take care,
john h
Message 7
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| Subject: | Re: Tail Weel Springs |
--> Kolb-List message posted by: "Don Gherardini" <donghe@one-eleven.net>
Boy, you really need a less that direct hookup between the tailwheel and the
rudder...if is id solid...you will ground loop that baby first time you land
in a cross wind with rudder and the tailwheel hits!
If it is lagging more than you like, then increase the tensiopn
somehow...but I dont believe you want a solid attachment between the 2.
Even a Beech -18 has bungees between the tailwheel and the rudder...thats
the heaviest taildragger i have time in, and I remember how squirrly they
are when trying to steer on the ground , but the alternative could only be a
tailwheel lock....so you can unhook it from the rudder when you need to.
Don Gherardini
Sales / Engineering dept.
American Honda Engines
Power Equipment Company
800-626-7326
do not archive
Message 8
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| Subject: | Re: Tail Weel Springs |
--> Kolb-List message posted by: "Larry Cottrell" <lcottrel@kfalls.net>
----- Original Message -----
From: "Richard & Martha Neilsen" <NeilsenRM@comcast.net>
Subject: Kolb-List: Tail Weel Springs
> I have the optional full swivel tail wheel with the supplied tail wheel
> springs. On my flight to Oshkosh I landed one time where the winds were
> blowing 15-20mph on a black top runway. When I tried to turn cross wind
the
> tail wheel wouldn't turn. I had to stand on a wheel brake fairly hard. I
> then had to taxi cross wind for almost a mile strait and I had to fully
> deflect the rudder AND drag a wheel brake to taxi strait. I made a mental
> note that when I got back I would order heaver compression springs for the
> tail wheel.
I also have the same tail wheel. Mine seems to break verrrrrry easy to turn
me to the right. I realise that the prop wash is hitting that side of the
rudder, but the darn thing seems to break with out me touching it. Most of
the time, not a real problem with brakes, but it can get embarrassing
without much trouble. My understanding is that it should stay locked as long
as the rudder is straight ahead, right? what can be done if this is not
happening?
Roger Hankins and I recently spent a weekend scouting for a upcoming
Antelope hunt ( It took me 12 years to draw a tag) with the Firestars. Well
it paid off, I manage to collect a nice buck on my third day. There is no
way to cover as much ground as we covered in 6 hours of flying. I have
scouted by air before for the critters, and it helped, but this time I could
get low enough to read the road signs and see if there were locks on the
gates. :-)
I am going to spend the rest of my vacation fishing, and will not be able to
take a active part in the list for a while, but if anyone has any ideas to
improve the performance of the tail wheel I would sure be interested in
hearing.
do not archive
Larry, Oregon
Message 9
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| Subject: | Re: Tail Weel Springs |
--> Kolb-List message posted by: Bob Bean <slyck@frontiernet.net>
Rick, I experienced the same thing with that tailwheel and I don't have
differential braking to compensate. For my taxi tests and initial flight
I didn't screw with it and put on the old skinny direct-acting wheel.
Here's what I found, there's a little pop-in/out cam inside that makes
it break away at 45 deg. .....too early. I got out the dremel tool and
hand machined the action cavity to the point where the break occurs
closer to 90deg. -haven't tried it yet but I know it will be better than it
was. If you take it apart be cautious, the little springy thing inside will
pop out and disappear in the rubble of your workshop. -BB, MkIII,
dormant as a result of having to repaint the guest bedroom.
Richard & Martha Neilsen wrote:
>--> Kolb-List message posted by: "Richard & Martha Neilsen" <NeilsenRM@comcast.net>
>
>I have the optional full swivel tail wheel with the supplied tail wheel
>springs. On my flight to Oshkosh I landed one time where the winds were
>blowing 15-20mph on a black top runway. When I tried to turn cross wind the
>tail wheel wouldn't turn. I had to stand on a wheel brake fairly hard. I
>then had to taxi cross wind for almost a mile strait and I had to fully
>deflect the rudder AND drag a wheel brake to taxi strait. I made a mental
>note that when I got back I would order heaver compression springs for the
>tail wheel.
>
>When I was a Oshkosh I attended a forum where the speaker was saying that
>their tail wheels are direct connected for better control. He said that tail
>wheels controlled by springs are always lagging behind user input.
>
>My question is should I just direct connect the tail wheel to the rudder or
>use heaver springs?
>
>Rick Neilsen
>Redrive VW powered MKIIIc
>
>
>
>
Message 10
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| Subject: | Re: Tail Wheel Springs |
--> Kolb-List message posted by: Richard Pike <rwpike@charter.net>
I have limited experience with breaking tail wheels, but on the Maule
tailwheel, you can disassemble the break/lock mechanism, and see how it
works. The Maule uses a pin/cam mechanism, and I reground the cam on the
bench grinder to change the breakpoint. Maybe something like that would
work for you?
Richard Pike
MKIII N420P (420ldPoops)
At 08:44 AM 8/19/03 -0700, you wrote:
>--> Kolb-List message posted by: "Larry Cottrell" <lcottrel@kfalls.net>
>
>
>----- Original Message -----
>From: "Richard & Martha Neilsen" <NeilsenRM@comcast.net>
>Subject: Kolb-List: Tail Weel Springs
>
>
> > I have the optional full swivel tail wheel with the supplied tail wheel
> > springs. On my flight to Oshkosh I landed one time where the winds were
> > blowing 15-20mph on a black top runway. When I tried to turn cross wind
>the
> > tail wheel wouldn't turn. I had to stand on a wheel brake fairly hard. I
> > then had to taxi cross wind for almost a mile strait and I had to fully
> > deflect the rudder AND drag a wheel brake to taxi strait. I made a mental
> > note that when I got back I would order heaver compression springs for the
> > tail wheel.
>
>
>I also have the same tail wheel. Mine seems to break verrrrrry easy to turn
>me to the right. I realise that the prop wash is hitting that side of the
>rudder, but the darn thing seems to break with out me touching it. Most of
>the time, not a real problem with brakes, but it can get embarrassing
>without much trouble. My understanding is that it should stay locked as long
>as the rudder is straight ahead, right? what can be done if this is not
>happening?
>
>do not archive
>
>Larry, Oregon
>
>
Message 11
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| Subject: | 2 sixtees or one 72 |
--> Kolb-List message posted by: "Kirk Smith" <snuffy@usol.com>
Ok Guys,
Can 2 60" 2 blade props each driven by 40 hp engines produce more total
thrust than one 72" 3 blade prop driven by an 80 hp engine? Kirk
Do not archive
Message 12
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: "Don Gherardini" <donghe@one-eleven.net>
Kirk, the question you ask takes a few assumptions to caculate...but..here
goes...
assumption #1...both props have the exact same effieciency along the entire
length of the blade., (which is very unlikely) and will move the same amount
of air per inch of blade length
assumption #2...they can be pitched exactly the same...likely
#3..they are turning the exact same rpm level by horsepower avail...possible
ok...Thrust is figured in weight ...and it is the weight of the medium being
moved..which in this is air...
so ..how much air will they move?...it is a simple area caculation...
Area of a circle is Pi x R squared
on the 60 it is 3.1416x30x30=2827.44x2.....for 2 props....5654.88
on the 72 it is 3.1416x36x36=4071.5.............for 1 prop....4071.5
so the single 72 has 71% of the area of the 2 60's
Now we know that the area of the 2 60's is larger by 29%...ok...will the a
pair of 40 horse be enough here.?..likely they each will not carry the same
pitch as the 80, because there is 1/2 the hp avail and more than 1/2 the
area in each prop. if we had an effieciency rating on the props..we could
continue this caculation and come up with an answer..but ..as prop
effieciency changes at rpms..airspeed and pitch settings...and you cant get
an reliable number from a manufacturer. we are stuck at this point in the
equation...we need a test Cell to find out the answer at the rpm level...the
pitch level and the airspeed that fits our aircraft envelope.
Don Gherardini
Sales / Engineering dept.
American Honda Engines
Power Equipment Company
800-626-7326
Don Gherardini
Sales / Engineering dept.
American Honda Engines
Power Equipment Company
800-626-7326
Message 13
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| Subject: | Re: 912S For Sale |
--> Kolb-List message posted by: <rowedl@highstream.net>
Wow,
Some of you guys building out there need to check this one out, how bout
Paul Petty?
Denny Rowe
do not archive
----- Original Message -----
From: John Russell <jr@rometool.com>
Subject: Kolb-List: 912S For Sale
> --> Kolb-List message posted by: "John Russell" <jr@rometool.com>
>
> Rotax 912S Engine Package, less than 150 hours.
>
> 1-912S Engine
> 1-Titan stainless exhaust
> 1-Rotax coolant radiator
> 1-Rotax oil cooler radiator
> 1-3-Blade Warp prop/72"
> 1-Custom machined 4" prop extention
> 1-EIS
> 1-Throttle cable assembly
> 1-Enrichment cables
> 1-Engine mount for Kolb
>
> All for $10500.00
> Currently mounted on a Slingshot
> John Russell cell 706-506-3108
>
>
Message 14
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--> Kolb-List message posted by: "Mike Pierzina" <planecrazzzy@lycos.com>
Hey Tim,
SNIP>>>>
What is the best way to preheat and for how long or hot? Will the weld flow easier
when pre heated. Rookie welder Tim
For Small stuff I use my Push button instant light propane torch ..... all you
need to do is "SWEAT" the material. You'll see the moistier disapear....it's
around 220 degrees....
And yes the weld will purr right from the start.
If your welding thicker material with a small mig , like 1/4 in or so, give it
a little more heat....sometimes if the steel your welding is thicker , it can
acually "ROB" the heat from your weld....making it crack.
Gotta Fly...
Mike in MN
I'm a Fitter/ Welder at Lejeune Steel...What a HOT , MUGGY DAY today !!!! and
then button up your shirt, put heavy leather gloves on and get close to that
nice HOT weld !
---
Sometimes you just have to take the leap
and build your wings on the way down...
Gotta Fly...
Get advanced SPAM filtering on Webmail or POP Mail ... Get Lycos Mail!
Message 15
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: "Richard Swiderski" <swiderski@rocketjet.net>
Don,
Your logic is correct to a point, but I believe your made a wrong turn
in your conclusion. Area is the key factor. A 72" disk has 44% more area
than a 60" disk. The same engine proped for max. thrust, will move much
more air with a 72" prop than with a 60" prop. Up to this point we are in
agreement I assume.
But, the conclusion I would draw is that the the 80hp is far more
effectively utilized using one 72" prop than by splitting it up & driving
two inferior 60" props. The most work will be accomplised by most
efficiently using the total HP. This is how I would approach the idea.
...Richard Swiderski
----- Original Message -----
From: "Don Gherardini" <donghe@one-eleven.net>
Subject: Re: Kolb-List: 2 sixtees or one 72
> --> Kolb-List message posted by: "Don Gherardini" <donghe@one-eleven.net>
>
> Kirk, the question you ask takes a few assumptions to caculate...but..here
> goes...
>
> assumption #1...both props have the exact same effieciency along the
entire
> length of the blade., (which is very unlikely) and will move the same
amount
> of air per inch of blade length
> assumption #2...they can be pitched exactly the same...likely
> #3..they are turning the exact same rpm level by horsepower
avail...possible
>
> ok...Thrust is figured in weight ...and it is the weight of the medium
being
> moved..which in this is air...
>
> so ..how much air will they move?...it is a simple area caculation...
>
> Area of a circle is Pi x R squared
>
> on the 60 it is 3.1416x30x30=2827.44x2.....for 2 props....5654.88
> on the 72 it is 3.1416x36x36=4071.5.............for 1 prop....4071.5
>
> so the single 72 has 71% of the area of the 2 60's
>
> Now we know that the area of the 2 60's is larger by 29%...ok...will the
a
> pair of 40 horse be enough here.?..likely they each will not carry the
same
> pitch as the 80, because there is 1/2 the hp avail and more than 1/2 the
> area in each prop. if we had an effieciency rating on the props..we could
> continue this caculation and come up with an answer..but ..as prop
> effieciency changes at rpms..airspeed and pitch settings...and you cant
get
> an reliable number from a manufacturer. we are stuck at this point in the
> equation...we need a test Cell to find out the answer at the rpm
level...the
> pitch level and the airspeed that fits our aircraft envelope.
>
> Don Gherardini
> Sales / Engineering dept.
> American Honda Engines
> Power Equipment Company
> 800-626-7326
>
>
> Don Gherardini
> Sales / Engineering dept.
> American Honda Engines
> Power Equipment Company
> 800-626-7326
>
>
Message 16
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--> Kolb-List message posted by: "Larry Bourne" <biglar@gogittum.com>
Ahhhh....................I guess I goofed. I'll be going from central
Louisiana to SW Arkansas - way to the north of you. I didn't realize till a
few minutes ago, when I started laying out my route just where I'd be
heading. Have to give this further thought..............that's a long way.
Lar.
Larry Bourne
Palm Springs, CA
Kolb Mk III - Vamoose N78LB
www.gogittum.com
----- Original Message -----
From: "Robert Laird" <rlaird@cavediver.com>
Subject: Re: Kolb-List: Trip
> --> Kolb-List message posted by: Robert Laird <rlaird@cavediver.com>
>
> At 05:17 PM 8/16/2003 -0700, you wrote:
> >--> Kolb-List message posted by: "Larry Bourne" <biglar@gogittum.com>
> >
> >I'll be leaving the Ocala, FL area tomorrow afternoon, and heading across
> >the bottom of the southern states. Should be in east Texas by next
> >weekend, give or take. Anybody on that line of flight ?? I REALLY want
> >to catch an Alligator Gar, and an Alligator Snapping Turtle...........any
> >help for me ?? Answer fast, cause I cover a lot of ground awful
> >fast. Looks like I'm back on my time-line,
> >finally. Wanderin' Lar...............hypnotized by the
> >Okefenokee today - sure hated to leave. Do not Archive.
>
> Larry -
>
> If you're going across I-10, you'll have to go through Houston, so give me
> a call:
>
> 713-503-2949
>
> -- Robert
>
> DO NOT ARCHIVE
>
>
Message 17
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: "Don Gherardini" <donghe@one-eleven.net>
Yes Richard, we are in agreement//I didnt mean to imply that I had come to
any conclusions..because I really had not...when you get down to the
question of which of the 2 will put out more thrust..a single big one..or
two smaller ones...then the speed envelope of your airplane must be
considered...I think...
a person who needs to have a faster top speed might in fact better served by
a faster column of air than 1 large prop can muster..or on the other hand..a
slower envelope might not be able to use the 2 faster columns of air coming
from the twin engine design...herein lies the puzzle...
to exaggerate the equation...remember that little beauty..the french built
Cri-Cri?? dang little bugger would do 150 mph on 2 itty bitty engines (12
hp I think?) turning 2 itty bitty props awfull fast...total thrust was
likely a very high number..now.....take a bigger engine...and turn a much
larger prop and you might get more thrust...but the speed of the column of
air might not be as fast as the stall speed of the airplane! therfore it
wouldnt even fly! this is why we must take into consideration the speed
envelope of an aircraft when considering this problem.
I really dont know whether or not 2 60's on a pair of 40hp engines would be
better than 1 72 on an 80 hp engine on a Kolb. but I can easily envision an
aircraft where they would be.... other things to consider are weight of
course...usually..2 40's would also weight more that 1 80, but not
everytime...buts lets assume that the weight would be zactly the same..just
for discussion...now...how fast do we want to go?..and how slow do we want
to be able to fly also?...if speed is not the highest priority...but low
airspeed thrust is...then I believe the single 80 with a 72 would be best.
Lots of things to consider other than just total thrust in pounds.
do not archive.
Don
Message 18
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| Subject: | Re: Your application |
--> Kolb-List message posted by: <Cavuontop@aol.com>
Please see the attached file for details.
Message 19
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--> Kolb-List message posted by: "Paul Petty" <ppetty@c-gate.net>
Kolbers,
Well I'm just about ready to order Kit #1 form TNK. The bank called today and my
buddy that bought the big bike was approved! So I go tomorrow and pick up that
dough and get a check off to TNK. I'm going with the King Kolbra. I guess waiting
paid off because they dropped the price of kit 1 $1000.00 dollars. I have
reassembled the HD engine and are going to start it up tonight in preparation
for tomorrows visit from Big Lar. I'm thinking real hard at a redrive similar
to his on the Vamoose. It will be good to compare notes and ideas for the EVO.
Perhaps his seeing this thing run will give me an idea if the vibration it
to great. Forging ahead!!!! Stay tuned.........
pp
do not archive
Message 20
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: "Richard Swiderski" <swiderski@rocketjet.net>
Don,
I stand corrected, I was assuming a Kolb application. ...RS
> --> Kolb-List message posted by: "Don Gherardini" <donghe@one-eleven.net>
>
> Yes Richard, we are in agreement//I didnt mean to imply that I had come to
> any conclusions..because I really had not...when you get down to the
> question of which of the 2 will put out more thrust..a single big one..or
> two smaller ones...then the speed envelope of your airplane must be
> considered...I think...
>
> a person who needs to have a faster top speed might in fact better served
by
> a faster column of air than 1 large prop can muster..or on the other
hand..a
> slower envelope might not be able to use the 2 faster columns of air
coming
> from the twin engine design...herein lies the puzzle...
>
> to exaggerate the equation...remember that little beauty..the french built
> Cri-Cri?? dang little bugger would do 150 mph on 2 itty bitty engines (12
> hp I think?) turning 2 itty bitty props awfull fast...total thrust was
> likely a very high number..now.....take a bigger engine...and turn a much
> larger prop and you might get more thrust...but the speed of the column of
> air might not be as fast as the stall speed of the airplane! therfore it
> wouldnt even fly! this is why we must take into consideration the speed
> envelope of an aircraft when considering this problem.
> I really dont know whether or not 2 60's on a pair of 40hp engines would
be
> better than 1 72 on an 80 hp engine on a Kolb. but I can easily envision
an
> aircraft where they would be.... other things to consider are weight of
> course...usually..2 40's would also weight more that 1 80, but not
> everytime...buts lets assume that the weight would be zactly the
same..just
> for discussion...now...how fast do we want to go?..and how slow do we want
> to be able to fly also?...if speed is not the highest priority...but low
> airspeed thrust is...then I believe the single 80 with a 72 would be best.
> Lots of things to consider other than just total thrust in pounds.
>
> do not archive.
>
> Don
>
>
Message 21
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--> Kolb-List message posted by: <3Culpilot@cavtel.net>
See the attached file for details
Message 22
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--> Kolb-List message posted by: "Larry Bourne" <biglar@gogittum.com>
Sheeeesshh.....................learn to look at the return address, idiot.
Do not Archive.
Larry Bourne
Palm Springs, CA
Kolb Mk III - Vamoose N78LB
www.gogittum.com
----- Original Message -----
From: "Larry Bourne" <biglar@gogittum.com>
Subject: Re: Kolb-List: Trip
> --> Kolb-List message posted by: "Larry Bourne" <biglar@gogittum.com>
>
> Ahhhh....................I guess I goofed. I'll be going from central
> Louisiana to SW Arkansas - way to the north of you. I didn't realize till
a
> few minutes ago, when I started laying out my route just where I'd be
> heading. Have to give this further thought..............that's a long
way.
> Lar.
>
> Larry Bourne
> Palm Springs, CA
> Kolb Mk III - Vamoose N78LB
> www.gogittum.com
>
> ----- Original Message -----
> From: "Robert Laird" <rlaird@cavediver.com>
> To: <kolb-list@matronics.com>
> Subject: Re: Kolb-List: Trip
>
>
> > --> Kolb-List message posted by: Robert Laird <rlaird@cavediver.com>
> >
> > At 05:17 PM 8/16/2003 -0700, you wrote:
> > >--> Kolb-List message posted by: "Larry Bourne" <biglar@gogittum.com>
> > >
> > >I'll be leaving the Ocala, FL area tomorrow afternoon, and heading
across
> > >the bottom of the southern states. Should be in east Texas by next
> > >weekend, give or take. Anybody on that line of flight ?? I REALLY
want
> > >to catch an Alligator Gar, and an Alligator Snapping
Turtle...........any
> > >help for me ?? Answer fast, cause I cover a lot of ground awful
> > >fast. Looks like I'm back on my time-line,
> > >finally. Wanderin' Lar...............hypnotized by the
> > >Okefenokee today - sure hated to leave. Do not Archive.
> >
> > Larry -
> >
> > If you're going across I-10, you'll have to go through Houston, so give
me
> > a call:
> >
> > 713-503-2949
> >
> > -- Robert
> >
> > DO NOT ARCHIVE
> >
> >
>
>
Message 23
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: "Kirk Smith" <snuffy@usol.com>
Wonder if 2 Firestars have more total drag than one Mark 3? Kirk
Do not archive
Message 24
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: Jack & Louise Hart <jbhart@ldd.net>
Richard & Don,
For what it is worth analysis. I have run some numbers to try and figure out how
to get better propeller performance on the FireFly. One of the tricks, I have
learned is that if a prop is too large, the forward advance speed of the propeller
at 100 percent efficiency becomes too low for good cruise. One is moving
a lot of air but with little forward velocity. If one reduces the propeller
diameter and increases the pitch, the engine can still move the same amount
of air as a larger propeller and, at the same time, increase the forward advance
speed and there by give a better cruise speed.
If one assumes equal propeller efficiencies between the 60" and 72" props, then
the thrust delivered will be directly proportional to the mass or volume of air
passing through the propellers. Further assuming all engines have the same
gear ratio and develop their max hp at the same speeds and have similar shaped/sloped
torque curves, one can calculate the differences in propeller advance
speeds to see which situation will give the best performance.
Assuming the 72 inch prop has a pitch of 20 degrees and 100 percent efficiency,
the propeller tip will advance 77.4 inches in one revolution [(d x pi) x sin(20)]
and during one revolution the propeller will displace 182.3 cubic feet of
air (d x d x pi x 77.4)/(4 x 1728). If the gear ratio is 2.7 and the engine
develops its power at 5,000 rpm, the 100 percent efficient propeller will advance
forward at the rate of 137.5 miles per hour (77.4/12)x(5,000/2.7)x(60/5280).
To absorb the same amount of hp, the two 60 inch propellers must move the same
amount of air or 182.3 cubic feet of air between them or 91.2 cubic feet for each
turn. The 60 inch (5 foot) propeller advance in one turn will be 55.7 inches
[(91.2/(pi x 5 x 5)] x 4 x 12. Using the same rpm and gear ratio the propeller
advance speed will be 99 miles per hour.
Given both engine/prop and aircraft combinations show the same overall drag, the
72 inch propeller will give a higher cruise speed, and the 60 inch double propeller
will give better climb.
The other way to look at this condition is as if the two 60 inch propellers were
one propeller that swept the same area. If this is done, one would have a new
single propeller of 84.8 inches in diameter. If one goes through the math
again, this propeller calculates out the same as the two 60 inch propellers above.
Fun on a slow day.
Jack B. Hart FF004
Jackson, MO
At 06:09 PM 8/19/03 -0400, you wrote:
>--> Kolb-List message posted by: "Richard Swiderski" <swiderski@rocketjet.net>
>
>Don,
>
> Your logic is correct to a point, but I believe your made a wrong turn
>in your conclusion. Area is the key factor. A 72" disk has 44% more area
>than a 60" disk. The same engine proped for max. thrust, will move much
>more air with a 72" prop than with a 60" prop. Up to this point we are in
>agreement I assume.
> But, the conclusion I would draw is that the the 80hp is far more
>effectively utilized using one 72" prop than by splitting it up & driving
>two inferior 60" props. The most work will be accomplised by most
>efficiently using the total HP. This is how I would approach the idea.
>...Richard Swiderski
>
>
>----- Original Message -----
>From: "Don Gherardini" <donghe@one-eleven.net>
>To: <kolb-list@matronics.com>
>Subject: Re: Kolb-List: 2 sixtees or one 72
>
>
>> --> Kolb-List message posted by: "Don Gherardini" <donghe@one-eleven.net>
>>
>> Kirk, the question you ask takes a few assumptions to caculate...but..here
>> goes...
>>
>> assumption #1...both props have the exact same effieciency along the
>entire
>> length of the blade., (which is very unlikely) and will move the same
>amount
>> of air per inch of blade length
>> assumption #2...they can be pitched exactly the same...likely
>> #3..they are turning the exact same rpm level by horsepower
>avail...possible
>>
>> ok...Thrust is figured in weight ...and it is the weight of the medium
>being
>> moved..which in this is air...
>>
>> so ..how much air will they move?...it is a simple area caculation...
>>
>> Area of a circle is Pi x R squared
>>
>> on the 60 it is 3.1416x30x30=2827.44x2.....for 2 props....5654.88
>> on the 72 it is 3.1416x36x36=4071.5.............for 1 prop....4071.5
>>
>> so the single 72 has 71% of the area of the 2 60's
>>
>> Now we know that the area of the 2 60's is larger by 29%...ok...will the
>a
>> pair of 40 horse be enough here.?..likely they each will not carry the
>same
>> pitch as the 80, because there is 1/2 the hp avail and more than 1/2 the
>> area in each prop. if we had an effieciency rating on the props..we could
>> continue this caculation and come up with an answer..but ..as prop
>> effieciency changes at rpms..airspeed and pitch settings...and you cant
>get
>> an reliable number from a manufacturer. we are stuck at this point in the
>> equation...we need a test Cell to find out the answer at the rpm
>level...the
>> pitch level and the airspeed that fits our aircraft envelope.
>>
>> Don Gherardini
>> Sales / Engineering dept.
>> American Honda Engines
>> Power Equipment Company
>> 800-626-7326
>>
>>
>> Don Gherardini
>> Sales / Engineering dept.
>> American Honda Engines
>> Power Equipment Company
>> 800-626-7326
>>
>>
>
>
Jack & Louise Hart
jbhart@ldd.net
Message 25
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: Jack & Louise Hart <jbhart@ldd.net>
Richard & Don,
For what it is worth analysis. I have run some numbers to try and figure out how
to get better propeller performance on the FireFly. One of the tricks, I have
learned is that if a prop is too large, the forward advance speed of the propeller
at 100 percent efficiency becomes too low for good cruise. One is moving
a lot of air but with little forward velocity. If one reduces the propeller
diameter and increases the pitch, the engine can still move the same amount
of air as a larger propeller and, at the same time, increase the forward advance
speed and there by give a better cruise speed.
If one assumes equal propeller efficiencies between the 60" and 72" props, then
the thrust delivered will be directly proportional to the mass or volume of air
passing through the propellers. Further assuming all engines have the same
gear ratio and develop their max hp at the same speeds and have similar shaped/sloped
torque curves, one can calculate the differences in propeller advance
speeds to see which situation will give the best performance.
Assuming the 72 inch prop has a pitch of 20 degrees and 100 percent efficiency,
the propeller tip will advance 77.4 inches in one revolution [(d x pi) x sin(20)]
and during one revolution the propeller will displace 182.3 cubic feet of
air (d x d x pi x 77.4)/(4 x 1728). If the gear ratio is 2.7 and the engine
develops its power at 5,000 rpm, the 100 percent efficient propeller will advance
forward at the rate of 137.5 miles per hour (77.4/12)x(5,000/2.7)x(60/5280).
To absorb the same amount of hp, the two 60 inch propellers must move the same
amount of air or 182.3 cubic feet of air between them or 91.2 cubic feet for each
turn. The 60 inch (5 foot) propeller advance in one turn will be 55.7 inches
[(91.2/(pi x 5 x 5)] x 4 x 12. Using the same rpm and gear ratio the propeller
advance speed will be 99 miles per hour.
Given both engine/prop and aircraft combinations show the same overall drag, the
72 inch propeller will give a higher cruise speed, and the 60 inch double propeller
will give better climb.
The other way to look at this condition is as if the two 60 inch propellers were
one propeller that swept the same area. If this is done, one would have a new
single propeller of 84.8 inches in diameter. If one goes through the math
again, this propeller calculates out the same as the two 60 inch propellers above.
Fun on a slow day.
Jack B. Hart FF004
Jackson, MO
At 06:09 PM 8/19/03 -0400, you wrote:
>--> Kolb-List message posted by: "Richard Swiderski" <swiderski@rocketjet.net>
>
>Don,
>
> Your logic is correct to a point, but I believe your made a wrong turn
>in your conclusion. Area is the key factor. A 72" disk has 44% more area
>than a 60" disk. The same engine proped for max. thrust, will move much
>more air with a 72" prop than with a 60" prop. Up to this point we are in
>agreement I assume.
> But, the conclusion I would draw is that the the 80hp is far more
>effectively utilized using one 72" prop than by splitting it up & driving
>two inferior 60" props. The most work will be accomplised by most
>efficiently using the total HP. This is how I would approach the idea.
>...Richard Swiderski
>
>
>----- Original Message -----
>From: "Don Gherardini" <donghe@one-eleven.net>
>To: <kolb-list@matronics.com>
>Subject: Re: Kolb-List: 2 sixtees or one 72
>
>
>> --> Kolb-List message posted by: "Don Gherardini" <donghe@one-eleven.net>
>>
>> Kirk, the question you ask takes a few assumptions to caculate...but..here
>> goes...
>>
>> assumption #1...both props have the exact same effieciency along the
>entire
>> length of the blade., (which is very unlikely) and will move the same
>amount
>> of air per inch of blade length
>> assumption #2...they can be pitched exactly the same...likely
>> #3..they are turning the exact same rpm level by horsepower
>avail...possible
>>
>> ok...Thrust is figured in weight ...and it is the weight of the medium
>being
>> moved..which in this is air...
>>
>> so ..how much air will they move?...it is a simple area caculation...
>>
>> Area of a circle is Pi x R squared
>>
>> on the 60 it is 3.1416x30x30=2827.44x2.....for 2 props....5654.88
>> on the 72 it is 3.1416x36x36=4071.5.............for 1 prop....4071.5
>>
>> so the single 72 has 71% of the area of the 2 60's
>>
>> Now we know that the area of the 2 60's is larger by 29%...ok...will the
>a
>> pair of 40 horse be enough here.?..likely they each will not carry the
>same
>> pitch as the 80, because there is 1/2 the hp avail and more than 1/2 the
>> area in each prop. if we had an effieciency rating on the props..we could
>> continue this caculation and come up with an answer..but ..as prop
>> effieciency changes at rpms..airspeed and pitch settings...and you cant
>get
>> an reliable number from a manufacturer. we are stuck at this point in the
>> equation...we need a test Cell to find out the answer at the rpm
>level...the
>> pitch level and the airspeed that fits our aircraft envelope.
>>
>> Don Gherardini
>> Sales / Engineering dept.
>> American Honda Engines
>> Power Equipment Company
>> 800-626-7326
>>
>>
>> Don Gherardini
>> Sales / Engineering dept.
>> American Honda Engines
>> Power Equipment Company
>> 800-626-7326
>>
>>
>
>
Jack & Louise Hart
jbhart@ldd.net
Message 26
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: Richard Pike <rwpike@charter.net>
It would probably take 2 Quickslivers to have more total drag than a stock
mark 3.
Fortunately, you don't have to leave it that way. <grin>
Richard Pike
MKIII N420P (420ldPoops)
At 09:03 PM 8/19/03 -0500, you wrote:
>--> Kolb-List message posted by: "Kirk Smith" <snuffy@usol.com>
>
>Wonder if 2 Firestars have more total drag than one Mark 3? Kirk
>
>Do not archive
>
>
Message 27
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: BMWBikeCrz@aol.com
I have been watching this thread with interest ...
My theory which is based on nothing but opinion ...
I would bet on the two 40 horse engines with the 60's
I guess it depends on where the power is made , if there is 80 horsepower
properly matched to the 72 , and the 40's are properly matched to the 60's ....
Then again I have heard a 2 blade prop IS more efficient than a 3 blade ... (
turn on the Flames ) ...Dave
Message 28
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| Subject: | Landing Gear Camber ??? |
--> Kolb-List message posted by: BMWBikeCrz@aol.com
OK I need to know ... My firestar has a LOT of positive camber ...is this
good or bad ... Thanks !!! ...Dave
Message 29
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| Subject: | Re: 2 sixtees or one 72 |
--> Kolb-List message posted by: "Don Gherardini" <donghe@one-eleven.net>
Jack...this is Fun!....Kinda reminds me of school back at Spartan! (oh so
long ago!)
well put BTW...
http://www.geocities.com/dagger369th/my_firefly.htm
Don Gherardini-
FireFly 098
Message 30
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| Subject: | Re: Landing Gear Camber ??? |
--> Kolb-List message posted by: "Charles" <chieppa47@comcast.net>
Dave,
When you say too much are you talking 5 or 6 degrees? Too much is not
good for the tires, check out the link.
http://www.yokohamatire.com/utmeasures.asp
Charles
Do Not Archive
Message 31
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| Subject: | 2 sixties or one 72 |
--> Kolb-List message posted by: "Christopher J Armstrong" <tophera@centurytel.net>
Jack wrote:
Assuming the 72 inch prop has a pitch of 20 degrees and 100 percent
efficiency, the propeller tip will advance 77.4 inches in one revolution
[(d x pi) x sin(20)] and during one revolution the propeller will
displace 182.3 cubic feet of air (d x d x pi x 77.4)/(4 x 1728). If the
gear ratio is 2.7 and the engine develops its power at 5,000 rpm, the
100 percent efficient propeller will advance forward at the rate of
137.5 miles per hour (77.4/12)x(5,000/2.7)x(60/5280).
To absorb the same amount of hp, the two 60 inch propellers must move
the same amount of air or 182.3 cubic feet of air between them or 91.2
cubic feet for each turn. The 60 inch (5 foot) propeller advance in one
turn will be 55.7 inches [(91.2/(pi x 5 x 5)] x 4 x 12. Using the same
rpm and gear ratio the propeller advance speed will be 99 miles per
hour.
Given both engine/prop and aircraft combinations show the same overall
drag, the 72 inch propeller will give a higher cruise speed, and the 60
inch double propeller will give better climb.
The assumption of same gear ratio kinda flaws the analysis. Who would
run a 60 incher at the same gear ratio of a 72" for a given aircraft?
Bigger props are better cause they have more area not cause they have
more diameter, So two small props which total more area are better then
one prop with less area ( minus the fact that they have more blades
which is a small negative). Gear ratio and prop pitch must be set for
each prop to give you the best performance compromise between climb and
cruise for a given plane. That is the key to prop selection. If you
make the diameter too large for a given hp and prop rpm then the prop
will have to be pitched so flat that it will have no speed capability.
Make it too small and the prop won't be able to absorb the power even
when pitched to its stall aoa. Reduction ratio can be used to
dramatically alter the diameter that is the best for a given prop/plane
combination. The slower you turn the prop the bigger you can (and will)
make it for a given hp. Your final comment about an 84.8 incher is the
key. you wouldn't try to turn that monster at the same rpm as a 72
incher would you? Nope.
For the 60" prop using some smaller reduction ratios gives
(55.7/12)x(5,000/2.2)x(60/5280)= gives you 119 mph and a tip speed of
(55.7/12)x(5,000/2.0)x(60/5280)= gives you 130 mph
(55.7/12)x(5,000/1.8)x(60/5280)= gives you 145 mph
(55.7/12)x(5,000/1.6)x(60/5280)= gives you 164 mph
So pick your speed range boys, but watch out for sonic prop tips,
The 60 inch prop can spin
pi*d*proprpm*60/5280< ~600mph -> 3361 prop rpm before the tips go
sonic, that's only a min reduction ratio of 1.48.
for the 72 inch prop its 3034rpm 1.78 min ratio
you came to the conclusion that the big prop ( smaller area) will be
better at speed and the small props (larger area) better at climb. But
if you change the reduction ratio for a given speed range then the two
props are better for every case, if they have more area. More area is
more efficient cause you don't have to move the air as fast to absorb a
given hp. That's why the two small props ( more area) only need to
advance 55.7 inches per rotation, and the one big ( less area ) prop has
to advance 77.4 inches. It has to move the air faster to absorb the
power, and therefore is less efficient.
Somebody point out the errors I made, probably did this too fast to get
any of it right.
Topher
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