Today's Message Index:
----------------------
1. 07:13 AM - Adventures in prop inertia, further (Richard Girard)
2. 08:06 AM - Re: Adventures in prop inertia, further (Larry Cottrell)
3. 08:06 AM - Re: Hanger location (Jim Dunn)
4. 08:15 AM - Re: Adventures in prop inertia, further (Jim Dunn)
5. 10:54 AM - Re: Adventures in prop inertia, further (Richard Girard)
6. 11:37 AM - Left/Right handedness V's control stick (Kirby Dennis Contr MDA/AL)
7. 12:13 PM - Re: Left/Right handedness V's control stick (Robert Laird)
8. 12:25 PM - Re: Left/Right handedness V's control stick (Richard Girard)
9. 12:33 PM - Re: Left/Right handedness V's control stick ()
Message 1
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| Subject: | Adventures in prop inertia, further |
Previously I published a list of props I tested per Rotax Service
Information instruction SI 11 UL 91 E. I just chased down the 68" four blade
Powerfin prop intended for the trike (officially refered to as Meadowlark
from here after). I say chased down because UPS was trying to deliver it to
an old address and the easiest way to get it was to go pick it up.
Speaking of UPS, I show up fat dumb and happy with no tracking number on the
day after their biggest day of the year which coincidentally was also the
day the computer at the customer counter decided that black was the color of
the day and took a hiatus. Five minutes after mumbling no to the question
"do you have a tracking number?" I had my prop and was on my way out the
door. Great job by Brown.
This test also gives me some anecdotal evidence to give Larry C. an answer
about the inertia of his two blade Warp Drive mounted on a "B" box. I think
you're okay on the limit of the "B" box ( 3000 kg cm ). Here's why:
Powerfin 68" 2 blade, 4 blade hub.
Wt. 6.88 lb ( 3.12 kg )
Average time to 30 oscillations 157 sec
Inertia 2800 kg cm
Powerfin 68" 4 blade, 4 blade hub.
Wt. 10.52 lb ( 4.77 kg )
Average time to 30 oscillations 183 sec
Inertia 5800 kg cm
Here you can see the direct relationship between the mass of the propellor
and the test results. Of course the only way to really know is to test the
two blade Warp Drive, but I think some reasonable reassurance can be had
inference.
Hope this helps
Rick
*Like the weather, everyone talks about prop inertia. Okay, maybe it's only a
few gearheads, but I got real interested after seeing the technique
demonstrated while doing the weight shift and powered parachute modules for
the repairman maintenance ticket. Having had plenty of time to think about
it while driving back home from CA, I figured I had four props I could check
and see how it all fit together. So I gathered them altogether and built the
setup per Rotax Service Information instruction SI 11 UL 91 E, Available
from the Rotax owners site and paraphrased in the CPS catalog. So here are
the numbers for a 66" Ritz 2 blade wood prop, a 66" Warp Drive 3 blade
straight carbon fiber prop with CNC aluminum hub, an IVO 60" 3 blade
composite prop with quick adjust hub, and a 48" 2 blade Tennessee Propellor
wood prop. Each prop was run 3 times and the times shown are the average of
the three, although each prop's runs were all +/- 1 second. I'll go heaviest
to lightest.
Warp Drive 66" 3 blade CNC hub
Wt. 9 lb. 12 oz.
Average time to 30 oscillations, 180 seconds
Inertia 5200 Kg cm^2
IVO 60" 3 blade Quick adjust hub
Wt. 6 lb. 4 oz.
Average time to 30 oscillations, 161 seconds
Inertia 2700Kg cm^2
Ritz 66 X 28 2 blade
Wt 5 lb. 1 oz.
Average time to 30 oscillations, 190 seconds
Inertia 3000 Kg cm^2
TPI 48 X 34 2 blade
Wt. 3 lb. 3 oz.
Average time to 30 oscillations, 127 seconds
Inertia 1100Kg cm^2
So there you have it, you can definitely see the variance in inertia caused
by length and mass. The Ritz is right at the top of the allowable range for
a B gearbox, while the shorter, heavier IVO is right near it and the TPI
shorty should represent no problem. The Warp drive is well within range of
the C and E gearboxes but would be brutal on a B box.*
--
Rick Girard
"Ya'll drop on in"
takes on a whole new meaning
when you live at the airport.
Message 2
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| Subject: | Re: Adventures in prop inertia, further |
----- Original Message -----
From: Richard Girard
To: kolb-list@matronics.com
Sent: Wednesday, December 20, 2006 8:12 AM
Subject: Kolb-List: Adventures in prop inertia, further
This test also gives me some anecdotal evidence to give Larry C. an
answer about the inertia of his two blade Warp Drive mounted on a "B"
box. I think you're okay on the limit of the "B" box ( 3000 kg cm ).
Here's why:
Thanks for the information. That makes me feel better. I had intended
to run it anyway, since it is so smooth and also appears to live up to
its press from Daryl. Daryl thought that it would give me about 10 mph
more speed, due to the design of the tips. It appears to have increased
the speed somewhere around 5 or so MPH. I did increase the tire size
from the wheel barrow tires to 8x600, which would of course cut my speed
quite a bit. Apparently the tip modification has off set the drag from
the tires and still have some speed left over. My last trip I increased
my pitch to 9 degrees, giving me about 63-6400 rpm on climb out. My
EGT's were just right, lower third of the 1100 range. I flew directly
East into a bit of a headwind at 5600 rpm with a speed of 62 average. On
my way back over the same route more or less, I was showing 69 MPH.
Larry, Ore
Message 3
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| Subject: | Re: Hanger location |
I agree. Orient the hangar so the prevaling wind is hitting against a
solid wall of the hangar -- NOT an opening (i.e., sides or back wall).
That way the building will shield the contents from the wind and not allow
lots of wind inside or through the hangar. I think best would be to have
the wind coming into the back wall, not the sides.
Jim
>
> My hanger has sliding doors, wood frame. The doors face the wind. In
> strong
> winds I am concerned about the doors blowing in on the plane. I would
> rather
> have the back or side on the strong wind side.
> Jerry
> ----- Original Message -----
> From: "Jim Dunn" <jim@tru-cast.com>
> To: <kolb-list@matronics.com>
> Sent: Tuesday, December 19, 2006 1:10 PM
> Subject: Kolb-List: Hanger location
>
>
>>
>> You want the hangar to take the wind, not the aircraft inside so I would
>> put the doors 90 degrees to the wind. I have an enclosed hangar with a
>> door on 1 side and I am sometimes concerned about the wind with the
>> ultralights sitting inside and the door open.
>>
>> If I were to build my hangar again, I would put a few tie-downs in the
>> concrete on the floor (probably along the centerline). The lift-up kind
>> that fall flush when not in use. They can be used as an anchor for
>> winching, or tie down in windy conditions with the door open, etc.
>>
>>>
>>> I have a question regarding hangers. There seem to be several self
>>> hanger
>>> builders on this site and I was wondering which direction would one
>>> have
>>> the "opened" ends positioned"?
>>>
>>> Ohio Ralph
>>
>>
>>
>>
>>
>>
>>
>
>
Message 4
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| Subject: | Re: Adventures in prop inertia, further |
Very interesting Rick.
So based on these data, can you estimate the max length 3-bladed QA IVO
prop that would be acceptable on a B box?
Thx,
Jim
>
> Warp Drive 66" 3 blade CNC hub
> Wt. 9 lb. 12 oz.
> Average time to 30 oscillations, 180 seconds
> Inertia 5200 Kg cm^2
>
>
> IVO 60" 3 blade Quick adjust hub
> Wt. 6 lb. 4 oz.
> Average time to 30 oscillations, 161 seconds
> Inertia 2700Kg cm^2
>
> Ritz 66 X 28 2 blade
> Wt 5 lb. 1 oz.
> Average time to 30 oscillations, 190 seconds
>
> Inertia 3000 Kg cm^2
>
> TPI 48 X 34 2 blade
> Wt. 3 lb. 3 oz.
> Average time to 30 oscillations, 127 seconds
> Inertia 1100Kg cm^2
>
> --
> Rick Girard
> "Ya'll drop on in"
> takes on a whole new meaning
> when you live at the airport.
>
Message 5
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| Subject: | Re: Adventures in prop inertia, further |
Jim, By rough estimate 64", based on nothing more than TLAR and a one sample
statistic.:-) Merry Christmas.
Rick
On 12/20/06, Jim Dunn <jim@tru-cast.com> wrote:
>
>
> Very interesting Rick.
>
> So based on these data, can you estimate the max length 3-bladed QA IVO
> prop that would be acceptable on a B box?
>
> Thx,
> Jim
>
> >
> > Warp Drive 66" 3 blade CNC hub
> > Wt. 9 lb. 12 oz.
> > Average time to 30 oscillations, 180 seconds
> > Inertia 5200 Kg cm^2
> >
> >
> > IVO 60" 3 blade Quick adjust hub
> > Wt. 6 lb. 4 oz.
> > Average time to 30 oscillations, 161 seconds
> > Inertia 2700Kg cm^2
> >
> > Ritz 66 X 28 2 blade
> > Wt 5 lb. 1 oz.
> > Average time to 30 oscillations, 190 seconds
> >
> > Inertia 3000 Kg cm^2
> >
> > TPI 48 X 34 2 blade
> > Wt. 3 lb. 3 oz.
> > Average time to 30 oscillations, 127 seconds
> > Inertia 1100Kg cm^2
> >
> > --
> > Rick Girard
> > "Ya'll drop on in"
> > takes on a whole new meaning
> > when you live at the airport.
> >
>
>
--
Rick Girard
"Ya'll drop on in"
takes on a whole new meaning
when you live at the airport.
Message 6
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| Subject: | Left/Right handedness V's control stick |
"David Lucas" wrote: << What layout do you prefer given your Left or
Right handedness and why, or is it even an issue? ... default position
for this Right-hander would be Stick in the Left hand and Throttle
handling and other switches etc done with the Right Hand. What do you
think? >>
David -
The stock configuration for the Mark-3 has the throttle in the center,
between the seats. During the building phase of my aircraft, I sat in
the pilot's seat (left side) several times, and practiced the "feel" of
my hands on the controls - right hand on the center-mounted stick, and
my left hand reaching across my stomach to grasp the throttle. (The
design intent for having the throttle in the center is, of course, so
that either occupant could control the throttle.)
That was the most awkward thing I've ever encountered in an airplane!
It convinced me that I must make the modification to put the throttle on
the left side of the cockpit, by my left thigh. Which I did. And my
setup is now comfortable and conventional: control stick in the right
hand, throttle in the left hand ... the way it SHOULD be!
Dennis Kirby
Mark-III, 912ul, in
Cedar Crest, NM
do not archive
Message 7
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| Subject: | Re: Left/Right handedness V's control stick |
Mine is in the stock configuration... weird at first, but it is quite
amazing what you can get used to***. What really kills me, though, is
when I decide to fly from the right seat, for grins. That really
messes me up!
-- Robert
*** My last plane had a HUGE throttle in the middle -- bigger than the
flap handle -- and the brake lever was attached to the throttle... it
took quite a while before I got used to THAT arrangement!!!
On 12/20/06, Kirby Dennis Contr MDA/AL <Dennis.Kirby@kirtland.af.mil> wrote:
>
> The stock configuration for the Mark-3 has the throttle in the center,
> between the seats.
do not archive
Message 8
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| Subject: | Re: Left/Right handedness V's control stick |
My Mk 3 flies from the right and has dual sticks. Puts everything where it
ought to be and I haven't really noticed it since the first few flights.
There's comfort in having the controls that have the most effect on your
flying in your hands all the time.
Rick
On 12/20/06, Robert Laird <rlaird@cavediver.com> wrote:
>
>
> Mine is in the stock configuration... weird at first, but it is quite
> amazing what you can get used to***. What really kills me, though, is
> when I decide to fly from the right seat, for grins. That really
> messes me up!
>
> -- Robert
>
> *** My last plane had a HUGE throttle in the middle -- bigger than the
> flap handle -- and the brake lever was attached to the throttle... it
> took quite a while before I got used to THAT arrangement!!!
>
> On 12/20/06, Kirby Dennis Contr MDA/AL <Dennis.Kirby@kirtland.af.mil>
> wrote:
> >
> > The stock configuration for the Mark-3 has the throttle in the center,
> > between the seats.
>
> do not archive
>
>
--
Rick Girard
"Ya'll drop on in"
takes on a whole new meaning
when you live at the airport.
Message 9
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| Subject: | Re: Left/Right handedness V's control stick |
>>There's comfort in having the controls that have the most effect on
your flying in your hands all the time.
Your head?
Sorry, couldn't resist.
-Ken
do not archive
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