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Author Topic: BLUEBIRD Ornithopter by birdkit.com 16 inch wingspan 1/4 ounce  (Read 1733 times)
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FreeFlightModeller
Russ Lister
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« Reply #75 on: August 03, 2019, 06:17:34 AM »

He probably dropped the robin thinking that he was going to score a bluebird!

The mention of trig and the memory aid "SohCahToa" immediately springs to mind .... one of the few memory aids that has worked for me.
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TheLurker
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« Reply #76 on: August 03, 2019, 11:17:01 AM »

Quote from: LASTWOODSMAN
The full grown deciduous trees are about  40  feet high, and the big mature Spruce trees are about  60 feet high.    I'll try the Tangent calculation   Huh   when I get out next and I remember to bring a piece of paper ...
For a quick and dirty approximation if you have a 45 degree angle from you to the 'bird then height = distance down-range* at the point you shoot the angle and you don't need to remember bits of paper++.

Quote from: FreeFlightModeller
"SohCahToa" immediately springs to mind .... one of the few memory aids that has worked for me.
Ditto.

Lurk.

*Subtract your height to correct**.
**Except there's not much point because you've got to estimate distance down-range and I don't know about you but I find if I can estimate an angle to +/- 5 degrees in hurry while spotting I'm doing extremely so well it's all a bit "wet finger guess" but it's better than nothing.

++Although if you take a square of paper with you, you can turn it into a very crude sextant by folding it diagonally to give you a 45 degree sightline.
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LASTWOODSMAN
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REAL PLANES HAD ROUND ENGINES AND TWO WINGS



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« Reply #77 on: August 03, 2019, 02:29:04 PM »

     Hi John.  That young Robin, that that Cooper's Hawk fledgeling was eating, was missing its primary and secondary and tail feathers - hence the solid "thud".    So the happy whistling cries we heard from that hawk, were not cries calling for food, but the same cries I have seen others make, when they are taking their time plucking, calling, and plucking again, and eating, calling, and eating again, just being happy and celebrating being alive, with a plump Robin meal ahead.  (just my guess ...   Cheesy   ).

      Hi FreeFlightModeller.   That "SohCahToa" is a perfect way to remember it for sure, but I can't recall ever using that in any of my classes at school here in the "Colony" called Canada.   

     Hi Lurker.   Those are very good ways to do it too.  I admit I roughly estimated the heights of those trees by the following method, as I forgot to bring a piece of  8 1/2" X  17"   printer paper.     I walked up to a tree.   I held my hand on the trunk two inches above my head and marked the spot, which is six feet.   Then I walked way out to the center of the Cricket field, and stuck out my arm  with middle finger and thumb measuring 6 feet at that mark (a cut off branch).  Then I just moved my hand up in increments -   the spruce had 10 increments = 60 feet , and the deciduous tree had about 7 increments =  42 feet.
     But I will bring that sheet of paper, line the paper bottom up with the horizon (flat as a board here in Essex County) to my eye, and mark a spot on the paper lined up with the top of the tree.   Then measure my "three foot" paces to the tree trunk for the "adjacent" length, do the calculation after measuring the angle on the paper, then add my standing height to the answer.   And see what the answer is ...

     I walked the dog in the calm first thing in the morning, then we grabbed the Bluebird Ornithopter, some clay, and a fresh length of  1/8" rubber for a two strand motor of 4",  in case I broke the rubber   Undecided, which I did ...   Grin
     It has been a drought  Tongue  and a heat wave for the lase four weeks in our neck of the woods.   The weather today Saturday August 3 2019,  when we got back at 11:00 AM  from flying,  was  79 deg F (84), winds blowing from the North at 6 mph gusting to 9 mph, 45% humidity.
     All finger winds:   70 winds = 15 sec,  80 winds = 18 sec,  90 winds = 20 sec,  100 winds = 20 sec.   It gets about four widening circles left, viciously fast and tight at first   Shocked , as it flaps and drifts downwind, finishing with nice long, slow soft glides, with wings up and stationary, and with sails full, at the end of flapping, until landing in the fairly good, long grass of my favorite Cricket Field.  But we made a whole bunch of flights just for fun.    Here are some pics in flight, and a pic of the "plague" in Jackson Park this year.

Pic #1      2688     The morning walkout.   Note the wind on the flag (finally a good day to fly).
Pic #2     2690     Morning flight going left.   This is the attitude of horizontal flight.  Almost at the top of the upstroke of the wing.
Pic #3     2691     Starting the downbeat.   Little wind in the clouds.
Pic #4     2692     Flat out.
Pic #5     2694     High cirrus with lower (snowman) cirrocumulus (?) clouds (?).    Maybe a bit of Altocumulous in there too.(?)
Pic #6     2697     Here is about 5 white female flightless Gypsy Moths laying their egg masses (100-1000) and covering them with their brown, poisonous, abdominal hair.  The spent emaciated females then die and fall off - lots of them in a pile by the trunk under the tree!!

Free Flight Rubber Powered Ornithopters. Lots of fun.   Cool

LASTWOODSMAN
Richard
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Re: BLUEBIRD Ornithopter by birdkit.com 16 inch wingspan 1/4 ounce
Re: BLUEBIRD Ornithopter by birdkit.com 16 inch wingspan 1/4 ounce
Re: BLUEBIRD Ornithopter by birdkit.com 16 inch wingspan 1/4 ounce
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OH, I HAVE SLIPPED THE SURLY BONDS OF EARTH ... UP, UP THE LONG DELIRIOUS BURNING BLUE ... SUNWARD I'VE CLIMBED AND JOINED THE TUMBLING MIRTH OF SUN-SPLIT CLOUDS ...
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« Reply #78 on: August 04, 2019, 09:35:02 PM »

Good stuff Richard - it does look very impressive up high against the clouds.

John
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« Reply #79 on: August 05, 2019, 05:20:47 AM »

The mention of trig and the memory aid "SohCahToa" immediately springs to mind .... one of the few memory aids that has worked for me.
[/quote]

I used to tell my students that "SOHCAHTOA" was Jalanese for trigonometry!!
Ron
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