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Rv 4-49...airfoils yak...rest in pieces!

Old 02-18-2012, 11:49 PM
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tobydogs
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Default Rv 4-49...airfoils yak...rest in pieces!

it was a bad day today to fly.....charged up batteries this morning cause last night said breezy today..but it was beautiful all the way to the field . brought the planes RV 4 -40,the profile airfoils yak[foamy],and the funjet ultra. enough batteries charged to fly each twice.building the dynaflite bot can wait!!

first up,the RV 4 40...club members surrounded me at my table and poured a ton of compliments on my covering job. i plug in the power and took of in 30ft...climbed right up to high enough to smile from ear to ear and think"sweet!!!!now i can trim....what the hll." she did a wing over and spiraled down to bury the motor 8" into the dirt. i believe i had an esc failure since i used a 85amp turnigy with a 5amp bec. i felt a dislike for the rv4 build from the first build of it 2 years ago. so i put the cheap stuff back in it thinking it didn't deserve better. i was very wrong,she was beautiful and deserved a power 60 eflite with the cc100amp ice i have sitting in a drawer.[must say i call this crash 100% pilot error...china cheap killed my bird].when i bought this esc years ago,it had just come out. after installing it the reviews were mixed by user's and i should have junked it then.

so the winds picked up to much for most of us to fly,but during a brief lull in the gusts i decided i wanted to fight the wind for fun ,wind sock wasn't blowing that hard and i came to fly...sooo up went the yak...lol...my throw away plane i call it.... well ,the wind won! go figure...i went up high enough to be flying a kite and thats how it looked..trying to fly directly into the wind at full throttle i watched it flying back wards,put it into a dive to flare and cut throttle as she dropped down the hillside out of site. would have been great if the wing didn't get ripped off on the landing. not worth repairing do to added weight.for $60 it's wroth replacing.but i'm not going to.

so the picture of the garbage bag is what happens when you combine 2 planes together. shheeeeeshh! what great day .....[really was great] one positive note,i p/u the funjet ultra and carried it carefully back to the car in great,unmaidened shape.
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Old 02-19-2012, 01:08 AM
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gramps2361
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Stuart that bites loosing any plane but 2 of them back to back that's just not right.

You never know with a ESC or UBEC when they are going to give up the ghost. I lost 3 planes last year only thing that was a common item on all three was a name brand UBEC never did hear from them what was the issue never will buy another item from them again either.

Made me laugh when you said you carefully carried the funjet back to the car I would of too.
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Old 02-19-2012, 01:14 AM
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gramps,we gotta laugh at times like these,i surprised i didn't slam the door on the fun jet.
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Old 02-19-2012, 01:18 AM
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Stuart that would of added insult to injury for sure!
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Old 02-19-2012, 09:11 PM
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max2112
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Dang! Sorry to read about your planes, Stuart.

I have 2 models myself that I have knowingly left B- quality electrics in because they aren't my "top shelf" birds.

Looking forward to read about the FunJet maiden!
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Old 02-20-2012, 12:59 AM
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thanks for commiserating with me on the crash max,i felt really annoyed to have finally finished the RV. also tossed about the idea of building another one,but i have to research what other companies make the RV kit.

today i at least put the idea of building another rv on the back burner for more fun projects. thats what takes our focus off losses...the gains of having so much fun to be had flying and building other planes..lol
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Old 01-16-2014, 02:15 AM
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2/18/2012 i destroyed the rv 4-40 due to poor equipment.

last winter in the begining of 2013 i started a new build of the rv and have completed it with the electrics and trim sheets[still needs trim work straightening]. all's that left is to fire her up when the props arrive this saturday. also need to glue the canopy on. i must admit...i really have had bad luck with the rv of the past,but they really are cool looking builds when done.

lesson learned regarding saving a few dollars buying cheap electronic. installed a new power 46 eflight motor,new castle 100amp esc,new 485 hitec servos,new hitec 6 channel rx,and i just bought a hitec eclips 7 tx this summer.

heres a few pictures of it's progress.
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Old 01-16-2014, 02:47 AM
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Stu that plane looks great you always do a awesome covering job. I think I have said that before about your planes.
I should ship my current build down to you for custom Stu covering job.

After watching some videos of this plane it does look like fun plane to knock about the sky. Good luck with this one at least with the quality components your good to go this time just don't report back about any dumb thumb action.
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Old 01-16-2014, 03:56 AM
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Wildflyer
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I try to always test a plane's internal systems, by looping a strong but soft rope around the front of the elevator, and then under or over the fuselage, as determined by shape. The other end of the loop is anchored solidly or hooked to my digital scale.

Then I will run a full battery pack out in a similar manner as a flight, full power for a while then cut back, etc. At the same time, I try to keep all servos moving.
Basically I am trying to make it fail, if there is a weak spot, I hope to find it.

At the end of the test, I use a digital thermometer to check the temp of the ESC, UBEC, and motor. Keep in mind, for an outrunner motor, we should check the temp of the internal winding's, not the outer shell, I have seen a difference of almost 100 degrees, between the two when I accidentally over propped a motor.

Plus This gives me a pretty good reference for a flight time, for each model.

For myself, if the plane can comfortably carry a separate receiver battery pack, then I will do that. A good well made pack, rarely gives out. And I do cycle my packs 2-3 times when new, and a few times during the season. While a pack is discharging on a cycler, rap it against the table, and gently pull on the wires, you might find a problem before it gets in the air.

I started doing this type of tests back in the 70's when radio systems and nicad batteries, were not nearly as reliable as they are now. And we had to test a nitro motor in all angles, and upside down etc. to know weather or not it would be running when you land.

These ground tests saved me from 3-4 system failers, but I didn't catch them all.
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Old 01-16-2014, 11:09 PM
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hello Dave,as i read your test procedure i thought of my glow/gas flying buds who strap their planes to the flight table as you described and run their motors to full throttle to test them before flying. i wouldn't run a electric motor on the ground[or workshop] wot for more time than a test to get the watts reading and to check the vertical lift.that takes max 30 seconds or less, i don't think taxiing around to long on the ground is a good idea due to lack of proper air flow through the components that require a flow of air to keep cool, but will taxi a bit to check how she's rolling before taking off on a maiden flight.

i fully tested everything on the RV i crashed and the failure on the esc was the same as all the reviews written up at hobbyking long after my purchase of the turnigy 85amp esc with a bec. i should have swapped it out for a turnigy plush as a cost effective choice and like my other planes of similar size used the rx battery.

now i'v swapped out all my turnigy larger motors and esc's for eflight power 60's and castle esc's.i also trust the brand new nimh rx 6v batteries i bought from hurc to replace my older ones after years of use and wouldn't want to tug on its wires to test them. with my luck i would be the reason they failed cause i tugged to hard...lol.


one thing your method of testing had me thinking...if a supplied air flow during the prolonged ground test you do by say a powerful fan or blower unit like an electric leaf blower were used,than you know your not pushing the components to their breaking point and possibly surviving the test but causing a weakness down the road. just a thought.

time to start dinner and glue the canopy on.
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