Measure the length of a pattern plane
#1
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Measure the length of a pattern plane
I was measuring the length of passport and found that I need to raise the tail wheel a couple inches off the ground to get the shortest length. Otherwise, the total length is longer. This is because the trailing edge of the rudder has a curve and the stick-out point is at the top.
So the question. Is the length of a pattern plane the length when all wheels are on the ground, or the shortest possible length after the tail is raised?
So the question. Is the length of a pattern plane the length when all wheels are on the ground, or the shortest possible length after the tail is raised?
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RE: Measure the length of a pattern plane
ORIGINAL: nonstoprc
I was measuring the length of passport and found that I need to raise the tail wheel a couple inches off the ground to get the shortest length. Otherwise, the total length is longer.
I was measuring the length of passport and found that I need to raise the tail wheel a couple inches off the ground to get the shortest length. Otherwise, the total length is longer.
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RE: Measure the length of a pattern plane
ORIGINAL: nonstoprc
So the question. Is the length of a pattern plane the length when all wheels are on the ground, or the shortest possible length after the tail is raised?
So the question. Is the length of a pattern plane the length when all wheels are on the ground, or the shortest possible length after the tail is raised?
Same goes for te prop position. The lowest tip of the front prop of Brenner CD comes in front of the spinner when placed in a vertical position (due to 2,5 degrees upthrust of the Gaudius)
So a horizontal prop gives a shorter model than a vertical prop position
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RE: Measure the length of a pattern plane
I noticed the same thing on my Passport in 09 before the worlds, and just to be sure I made a rudder with the straigth trailing edge and same area so it will be shorter, model flew exactly the same and you can be relaxed in every model processing.
#6
RE: Measure the length of a pattern plane
Surely it must be measured with the body/datum line set at zero... not at an angle.
Otherwise you could hold a much larger model at 45deg and fit it in the box.
Who specifies the angle? Must be zero.
My you, never under estimate the European Bureaucrat.
Otherwise you could hold a much larger model at 45deg and fit it in the box.
Who specifies the angle? Must be zero.
My you, never under estimate the European Bureaucrat.
#7
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RE: Measure the length of a pattern plane
ORIGINAL: David Bathe
Surely it must be measured with the body/datum line set at zero... not at an angle.
Otherwise you could hold a much larger model at 45deg and fit it in the box.
Who specifies the angle? Must be zero.
My you, never under estimate the European Bureaucrat.
Surely it must be measured with the body/datum line set at zero... not at an angle.
Otherwise you could hold a much larger model at 45deg and fit it in the box.
Who specifies the angle? Must be zero.
My you, never under estimate the European Bureaucrat.
You hit on something of a misnomer in the regulations....Wherever the regs state that the model shall fit inside a 2 meter X 2 meter box, biasing the model will allow it to easily fit even if it's more than 2 meters long or wide. Of course that lands you outside the spirit of the regulation.
I had not thought of it before but it makes sense. Any verbiage that references a 2m X 2m box should be stricken from the regs. I've never seen any verbiage that spells out orthogonal measurement
The way a model is processed is correct....a set of calipers with jaws 2 meters apart. The regs should only reflect that and be done with it
#9
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RE: Measure the length of a pattern plane
ORIGINAL: nonstoprc
On model processing at Worlds or Nats, just wonder how the measurement is made.
If the caliper method is used, how does the official make sure that the long bar of the caliper is parallel to the datum line?
On model processing at Worlds or Nats, just wonder how the measurement is made.
If the caliper method is used, how does the official make sure that the long bar of the caliper is parallel to the datum line?
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RE: Measure the length of a pattern plane
ORIGINAL: nonstoprc
On model processing at Worlds or Nats, just wonder how the measurement is made.
If the caliper method is used, how does the official make sure that the long bar of the caliper is parallel to the datum line?
On model processing at Worlds or Nats, just wonder how the measurement is made.
If the caliper method is used, how does the official make sure that the long bar of the caliper is parallel to the datum line?
#13
RE: Measure the length of a pattern plane
Hummm, certainly not zero there then.
Maybe they allow for a little jiggery-pockery... lifting the tail to squeeze in a couple of mm's? Then again.
Judging from that pic, our German friend seems to be way inside.
Optical illusion?
Maybe they allow for a little jiggery-pockery... lifting the tail to squeeze in a couple of mm's? Then again.
Judging from that pic, our German friend seems to be way inside.
Optical illusion?
#16
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RE: Measure the length of a pattern plane
ORIGINAL: highfly3D
Is the length measured from the tip of the spinner to the rudder??
Is the length measured from the tip of the spinner to the rudder??
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RE: Measure the length of a pattern plane
Legend has it that the "F3A" spinner profile (shorter than a "standard" spinner profile) came about as a result of the size rule: it allows more "airplane" to fit within the length constraint.
John Pavlick
John Pavlick
#18
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RE: Measure the length of a pattern plane
ORIGINAL: jrpav1
Legend has it that the ''F3A'' spinner profile (shorter than a ''standard'' spinner profile) came about as a result of the size rule: it allows more ''airplane'' to fit within the length constraint.
John Pavlick
Legend has it that the ''F3A'' spinner profile (shorter than a ''standard'' spinner profile) came about as a result of the size rule: it allows more ''airplane'' to fit within the length constraint.
John Pavlick
...and a few grams of weight savings plus IMHO they look better on the current fuse shapes compared to a standard shape spinner.
#19
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RE: Measure the length of a pattern plane
Glen,
Thanks for the pictures posted. Very helpful.
Sounds like, lengthwise, it will be a pass if the model can fit within the 2m caliper, provided that the tip of the spinner (if any) and the TE of the rudder are within the box outlined by the bar, and two jaws of the caliper.
On the 82mm f3a carbon fiber spinner sold by Chris at f3a unlimited, can somebody measure the height? My Passport requires one with height less than 62mm in order to pass the 2m rule. Assume no surgery work at the TE of the rudder. I was not able to get the info this week from Chris. Thanks
Thanks for the pictures posted. Very helpful.
Sounds like, lengthwise, it will be a pass if the model can fit within the 2m caliper, provided that the tip of the spinner (if any) and the TE of the rudder are within the box outlined by the bar, and two jaws of the caliper.
On the 82mm f3a carbon fiber spinner sold by Chris at f3a unlimited, can somebody measure the height? My Passport requires one with height less than 62mm in order to pass the 2m rule. Assume no surgery work at the TE of the rudder. I was not able to get the info this week from Chris. Thanks
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RE: Measure the length of a pattern plane
Hi John,
Hi All,
the profile that our friends at Tru-Turn call "FAI" was intended to preserve the look of a 2-1/4" FOX "conical" spinner.
It seemed that nearly every fiberglass fuselage plug for those kits popular at the time (early 80's) was carved to match that same FOX spinner.
It was clearly lighter and better balanced than anything else on the market at the time.
So what was Bob Obenberger supposed to call it? Sorta-like-a-FOX? I think not.
The FAI Pattern guys asked for it, so that's what he called it.
At the time (back when engine displacement was the "real" limit) length was immaterial.
So endeth the history lesson.
take care,
Dean Pappas
Hi All,
the profile that our friends at Tru-Turn call "FAI" was intended to preserve the look of a 2-1/4" FOX "conical" spinner.
It seemed that nearly every fiberglass fuselage plug for those kits popular at the time (early 80's) was carved to match that same FOX spinner.
It was clearly lighter and better balanced than anything else on the market at the time.
So what was Bob Obenberger supposed to call it? Sorta-like-a-FOX? I think not.
The FAI Pattern guys asked for it, so that's what he called it.
At the time (back when engine displacement was the "real" limit) length was immaterial.
So endeth the history lesson.
take care,
Dean Pappas
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RE: Measure the length of a pattern plane
ORIGINAL: nonstoprc
Received the height info for Chris for the 82mm MarQuet spinner. It is 73.5mm. 8.5mm more than what is ideal. Too bad.
Received the height info for Chris for the 82mm MarQuet spinner. It is 73.5mm. 8.5mm more than what is ideal. Too bad.
So if you like gambling....
Magne
#24
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RE: Measure the length of a pattern plane
A 1% deviation in length would be more than adequate. The US AMA 2011-2012 competition rule cited below, though, does not say it.
"4.3: Weight and Size: No model may weigh more than 5000 grams gross, excluding fuel, ready for takeoff. Electric models are weighed with batteries. In Sportsman, Intermediate and Advanced an allowance of 115 grams is permitted. No model may have a wingspan or total length longer than two (2) meters (78.74 inches).
Wherever practical, all aircraft should be weighed prior to the start of the contest. If weight is being enforced then all planes competing in that class must be weighed before the same round (round 1 or otherwise) for a baseline. Only two attempts at making weight will be allowed on the day specified for weigh- in. If no calibration system is available for the scales, a tolerance of 50 grams will be allowed for possible inaccuracies in the measurement instrument."
I probably will cut the current spinner slightly to meet the 2m rule.
"4.3: Weight and Size: No model may weigh more than 5000 grams gross, excluding fuel, ready for takeoff. Electric models are weighed with batteries. In Sportsman, Intermediate and Advanced an allowance of 115 grams is permitted. No model may have a wingspan or total length longer than two (2) meters (78.74 inches).
Wherever practical, all aircraft should be weighed prior to the start of the contest. If weight is being enforced then all planes competing in that class must be weighed before the same round (round 1 or otherwise) for a baseline. Only two attempts at making weight will be allowed on the day specified for weigh- in. If no calibration system is available for the scales, a tolerance of 50 grams will be allowed for possible inaccuracies in the measurement instrument."
I probably will cut the current spinner slightly to meet the 2m rule.
#25
RE: Measure the length of a pattern plane
ORIGINAL: David Bathe
Now this is gambling.
If one has to fit in a 2m box, couldn't you interpretate it like this?
Compare the size difference.
Now this is gambling.
If one has to fit in a 2m box, couldn't you interpretate it like this?
Compare the size difference.
For FAI that is not the rule.
There is no mention of a '2m box' - there never was.
The code in summary says ; Max,, Length =2000mm, max wingspan = 2000mm with +/_ 1% for instrument tolerance.
Effectively 2020mm on any given day with any given measuring device.
Brian