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General control line discussion => Open Forum => Topic started by: Skip Chernoff on July 24, 2017, 04:26:28 PM
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While at Brodaks I noticed our "Pit Boss" Dave using a nice chart for knowing how much to pull each plane based on the plane's weight in ounces. Does anyone have a copy of that and may I have one? Any help will be much appreciated .Thanks,PhillySkip <skipchernoff@hotmail.com>
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Airplane weight in pounds, times ten, rounded up to the nearest pound.
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Thanks Tim.
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Here are a couple of forms we use here in the NW.
Note that the pull test numbers are rounded to the nearest 5 lbs, to make scale reading easy. The numbers err on the high side
so the pull test is always 10G minimum, and rounded up slightly to hit the 5 lb increment. Most of our scales (and pull test 'operators'!)
don't read any more accurately than that anyway!
Dave G.
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Thanks Dave,I'll print up both of those forms.Much appreciated, PhillySkip
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I do not post much on SH, but I could not let this go by. I am not criticising anyone here, just trying to inform all. If you take it as an attack on you, please explain your position so I can officially apologize to you if I am wrong.
Now the meat of my post. This pull test chart is in no way in compliance with AMA rules in the rulebook. There is no allowance for slightly rounding up weights to anything. Weights are weights, period. To pick an arbitrary number like 5 pounds is interesting, but let's run with it. If my plane comes in at 40.01 ozs I get pulled 4 pounds more than I should at 30 lbs. 40.01/16=2.500625. 10x 2.500625=25.00625 lbs. So I'm sure my previous statement is incorrect because rounding my pull weight to 26 lbs is appropriate and correct and is probably in the rules somewhere. Now the really disturbing part. "Most of our scales (and pull test 'operators'!)
don't read any more accurately than that anyway!" So, let's plug this into my pull test weight. I'll just pick 10 percent error. Test scale at this error percent could present a 3 lb error, and the operator could present another 3 lb error, resulting in a 6 lb error. So my test weight that starts out at 4 lbs too much could escalate to 10 lb error. Agree this could be +or - however I do not want my bellcrank laying on the ground because of this.
I think this chart is just laziness to do calculations properly or to save paper to make an accurate chart. Also to state your equipment and people are in error, that MUST be addressed. Also note that if a CD uses this chart to officiate a C/L contest he is not acting in his agreement to comply with the rules that the AMA dictates he MUST follow. Dollar general sells calculators at very cheap prices and most modern phones have cal functions and planes are weighed at registration so just make things more accurate than this chart for pull testing.
Sorry if it seems like I'm ranting or rambling on about something stupid, but I pit bossed at Nats for 4 years, (not last year) and pulled out zero bellcranks, and found 1 thong that failed and was quickly fixed.
Again, I am not trying to offend anyone, just to inform. I'm sure I ruffled someone's feathers and that's why I do not post much on SH. I don't need the aggravation that comes along. However my butt is in the wind now so yall can start spanking it.
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What is wrong with having a chart showing the pounds of pull test for the weight of the plane in stead of having to use a calculator. Weigh the plane look at chart and write the pull test on score sheet. Is that so hard to do. S?P
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Unless it is an F2D aircraft......44lbs!!!
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OK Mr. John. i'll try to explain in simple words. The chart that was posted, if you cared to look at it is not what I consider to be ugggghhhh. Just download the chart, then reread my post, and
Now you know why I do not post a lot. Just forget it. I will not be drug into a pissing contest.
DAVE
I'm done.
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I think this chart is just laziness to do calculations properly or to save paper to make an accurate chart.
If you're worried about getting pulled a few pounds high on the pull test, then you didn't pay enough attention to structure when you built the plane!! Pit boss is not a job that gets much glory, and with a handy chart there's no need to restrict the job to a mathematician.
We're having trouble finding pit bosses, not to mention contest directors -- you want to come out to the NW and do all the work to organize and run our contests, and the pits? Then you can make the calculations as accurately as you'd like.