Lumenier RB2205C-12 2400KV SKITZO Ceramic Bearing Motor
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Old Apr 07, 2012, 06:01 AM
Woodstock 1 is offline
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Congratulations! Looking forward to some video!
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Old Apr 14, 2012, 02:22 PM
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Video


I managed to get the video off the camera and uploaded to youtube:

Skybench Merlyn (4 min 3 sec)


Two flights. I really like the sun coming through the monokote on the wings.
Old Apr 15, 2012, 09:56 AM
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Skye Malcolm, LSF Secretary
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Dick,
I always love to see your planes out at the field, I aspire to that level of finish get on your planes. Heck you even made that Vista look pretty!

Another absolutely gorgeous plane, sorry I couldn't make it to the field on a weekday, things are busy at work for sure.
-Skye
Old Apr 15, 2012, 05:50 PM
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Dick,
I always love to see your planes out at the field, I aspire to that level of finish get on your planes. Heck you even made that Vista look pretty!

Another absolutely gorgeous plane, sorry I couldn't make it to the field on a weekday, things are busy at work for sure.
-Skye
You'll get another opportunity to see it. One thing that I hadn't mentioned before, was the wing joiner rod took a bend....Jay said I had built dyhedryal into the rod. I need to replace it we a harder rod....3/8 inch drill rod was not strong enough.
Old Apr 15, 2012, 07:53 PM
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Gasbags & Gussets
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two ?


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Originally Posted by rjrobbin View Post
You'll get another opportunity to see it. One thing that I hadn't mentioned before, was the wing joiner rod took a bend....Jay said I had built dyhedryal into the rod. I need to replace it we a harder rod....3/8 inch drill rod was not strong enough.
Now that you have walked the walk, do you think there is enough room to put two rods in or is it pretty much limited to a single bigger or stronger rod ?

thanks for looking and congradulations again, john s.
Old Apr 15, 2012, 08:12 PM
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Now that you have walked the walk, do you think there is enough room to put two rods in or is it pretty much limited to a single bigger or stronger rod ?

thanks for looking and congradulations again, john s.
I am trying to get a hardened rod from Dixie Pins. Bigger or multiple rods would require major wing surgery. Not likely to happen.
Old Apr 16, 2012, 11:56 AM
rev.iain is online now
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Mesa AZ, it's a dry heat!

wing rods


I built a Merlyn back in 1982, not electric of course. I never did manage to bend the wing rod, but then there were no 'gorrila' winches, so it was a case of 'easy does it'.
I believe I used a "Squires" wing rod in those days. I don't believe Dave Squires is still in bussiness. His rods were excellent.
Be careful with very hard rods, they may be brittle. I used to be able to calculate the requred modulus and all that stuff, but I am retired now and my brain is contracting!

Beautiful bird by the way, I might be tempted to build another for e-power.

Iain
Old Apr 16, 2012, 01:53 PM
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I built a Merlyn back in 1982, not electric of course. I never did manage to bend the wing rod, but then there were no 'gorrila' winches, so it was a case of 'easy does it'.
I believe I used a "Squires" wing rod in those days. I don't believe Dave Squires is still in bussiness. His rods were excellent.
Be careful with very hard rods, they may be brittle. I used to be able to calculate the requred modulus and all that stuff, but I am retired now and my brain is contracting!

Beautiful bird by the way, I might be tempted to build another for e-power.

Iain

This is what I found:

1 6061K325 Hardened Precision Steel Shaft, 3/8" Diameter, 15" Length

from McMaster-Car. they said the rocwell was equiv to a 60....
Old Apr 16, 2012, 03:48 PM
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Mesa AZ, it's a dry heat!

Wing rods


I would be tempted to buy one, and do a bend test to make sure it will bend rather than break. If it does not break then get another to use in the model.
Better to find out on the ground than at 500'!

Iain
Old Apr 16, 2012, 04:33 PM
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I would be tempted to buy one, and do a bend test to make sure it will bend rather than break. If it does not break then get another to use in the model.
Better to find out on the ground than at 500'!

Iain
Yes. Bending rather than breaking any day. The bend is a good way to absorb the excess energy there. It's also easier to straighten a bendy rod than a brittle one: I use a rubber mallet judiciously applied to the top of the bend...
Old Apr 16, 2012, 07:12 PM
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I would be tempted to buy one, and do a bend test to make sure it will bend rather than break. If it does not break then get another to use in the model.
Better to find out on the ground than at 500'!

Iain
Ordered 2
Old Apr 16, 2012, 07:13 PM
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Yes. Bending rather than breaking any day. The bend is a good way to absorb the excess energy there. It's also easier to straighten a bendy rod than a brittle one: I use a rubber mallet judiciously applied to the top of the bend...
Interesting....
Old Apr 17, 2012, 06:37 AM
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Skye Malcolm, LSF Secretary
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Ordered 2
Now the really scientific way would be to get the old rod and the extra new rod and do a bend test in an Instron machine. We could plot the Force vs stroke and see how much stiffer this new rod is compared to the old one.

But barring that a big vice and a pipe as a breaker bar might be strong enough to bend each of these. Then just use your calibrated oomph-meter to determine how much stronger the new one is compared to the old one.
Old Apr 17, 2012, 07:53 AM
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Now the really scientific way would be to get the old rod and the extra new rod and do a bend test in an Instron machine. We could plot the Force vs stroke and see how much stiffer this new rod is compared to the old one.

But barring that a big vice and a pipe as a breaker bar might be strong enough to bend each of these. Then just use your calibrated oomph-meter to determine how much stronger the new one is compared to the old one.
ok...I am reluctant to start this discussion...I have never used a 'oomph-meter'. Is it calibrated in ergs?

for the uniformed... "An erg is the unit of energy and mechanical work in the centimetre-gram-second (CGS) system of units"

after all this is just an airplane made out of wood held together with glue.....
Old Apr 17, 2012, 01:40 PM
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ok...I am reluctant to start this discussion...I have never used a 'oomph-meter'. Is it calibrated in ergs?

for the uniformed... "An erg is the unit of energy and mechanical work in the centimetre-gram-second (CGS) system of units"

after all this is just an airplane made out of wood held together with glue.....
If we do the simple bend test with a breaker bar I would suggest the universal plumber/auto mechanic's unit of measure of torque: grunts. But you can always skip the component spec and go straight to the flight test to check for brittle failure mode.

Again, if an instron is available we would be able to measure a force in N or lb off a load cell.


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