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Old Jan 09, 2009, 09:34 AM
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jfetter's Avatar
Miramar, Florida
Joined Jul 2007
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Quote:
Originally Posted by dag214
Another thing I am trying to figure out, it looks like I am turning a lot more RPM's than I should.
Dag,

Did you program the controller using the Spin box? The easiest way is what I said before, select "Auto" and choose "Outrunner". I say this because there are settings that can affect not only the motor running correctly but the readings on the Spin (RPM being one of them), mainly the correct number of poles. The only way you should be able to turn that many RPM's would be to run in excess of 35 Volts...

Jack
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Old Jan 09, 2009, 09:36 AM
HAL... Open the damn doors!
jfetter's Avatar
Miramar, Florida
Joined Jul 2007
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Quote:
Originally Posted by dag214
All,
One other thing,
When my final assembly bench is complete I will be able to test run all six motors at once in the wing. It won't show me what is happening in the air, but it will show what 6 motors turning at once will do setting on the ground at full power.

Thanks all,
DAG
THAT will make a sweet video! Make sure you tack something behind it that shows the airflow (floppy rag or something cloth), I can imagine how violent it will be standing behind it!

Jack
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Old Jan 09, 2009, 09:57 AM
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Australia, NSW, Forster
Joined Oct 2004
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Dag, that 5900rpm reading sounds a bit like the revs are being calculated for a 2 blade prop. If so, the real rpm would be 2/3*5900 which is 3933, which sounds mighty close to what you were expecting.
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Old Jan 09, 2009, 10:05 AM
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jfetter's Avatar
Miramar, Florida
Joined Jul 2007
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Quote:
Originally Posted by Tonystott
Dag, that 5900rpm reading sounds a bit like the revs are being calculated for a 2 blade prop. If so, the real rpm would be 2/3*5900 which is 3933, which sounds mighty close to what you were expecting.
The Spin box uses poles, it knows nothing about blades, as far as it is concerned, there is no prop...

Jack
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Old Jan 09, 2009, 10:08 AM
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jfetter's Avatar
Miramar, Florida
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BTW Dag, the Hacker A60 16L is a 14 pole motor in case you don't have the specs handy...

Jack
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Old Jan 09, 2009, 11:43 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Quote:
Originally Posted by jfetter
BTW Dag, the Hacker A60 16L is a 14 pole motor in case you don't have the specs handy...

Jack
Thanks Jack,
I just set it to 14 poles and said my RPM were 3200, and that was after running the battery for over 2 minutes at 100% throttle. I wanted to run the test while having lunch.

Back to work now.

DAG
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Old Jan 09, 2009, 12:03 PM
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Miramar, Florida
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Quote:
Originally Posted by dag214
Thanks Jack,
I just set it to 14 poles and said my RPM were 3200, and that was after running the battery for over 2 minutes at 100% throttle. I wanted to run the test while having lunch.

Back to work now.

DAG
That sounds better!

So it looks like your seeing about 82% efficiency (it's a big prop with a lot of pitch, seems in-line with expectations since it's a static load on that bench). Given that, you should be turning 4,270 when you switch to 8S. Of course this all changes once you start moving through the air, that plus higher capacity or higher C-rated batteries can also play a part as I am estimating your current packs are currently holding 95% voltage under load...

Jack
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Old Jan 09, 2009, 12:09 PM
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Miramar, Florida
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Dag,

Not sure how much into electrics you are getting or if you are into attending fly-ins and other R/C events there is an event called SEFF held every year in Americus, GA. Last year we had 458 registered pilots and some 3,000 planes, it's an electric-only event!

Not sure if you would consider travelling 700 miles (distance to you) or hauling the B-36 or if it will even be done by the beginning of May but it sure as heck would be one cool plane to bring, you wouldn't believe what other folks are doing with electrics!

Jack
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Old Jan 09, 2009, 02:56 PM
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Denmark
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Quote:
Originally Posted by dag214
I have learned everything I have about machining from books and trial and error. When I drill out the center of my tubing on my shafts to tap for my 8mm stud I seem to always have just a small amount of slop. I am making the new shafts tonight and we will see how it goes. The long 28 nacelle #3&#4 shafts will be aluminum, but the rest will be CF (I think).
I asume You're using a lathe for the boring and thread cutting.
Why not make the axle 15-20mm to long and counterbore it to 8mm and step down to 6,75mm.
Then this vill steer the tap and no wobbling will ocur.
When You're done cut the exess off and be done.

Henrik
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Old Jan 09, 2009, 03:03 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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[QUOTE=Chickenthief][QUOTE=dag214]I have learned everything I have about machining from books and trial and error. When I drill out the center of my tubing on my shafts to tap for my 8mm stud I seem to always have just a small amount of slop. I am making the new shafts tonight and we will see how it goes. The long 28 nacelle #3&#4 shafts will be aluminum, but the rest will be CF (I think).
Quote:

I asume You're using a lathe for the boring and thread cutting.
Why not make the axle 15-20mm to long and counterbore it to 8mm and step down to 6,75mm.
Then this vill steer the tap and no wobbling will ocur.
When You're done cut the exess off and be done.

Henrik
That sounds spot on perfect, I will try it.

Thanks!

DAG
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Old Jan 09, 2009, 03:41 PM
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Miramar, Florida
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Dag,

This is what a Mejzlik (pronounced "May-Schlik") prop looks like;

Artwork!

Jack
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Old Jan 09, 2009, 04:56 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Quote:
Originally Posted by jfetter
Dag,

This is what a Mejzlik (pronounced "May-Schlik") prop looks like;

Artwork!

Jack
Very cool Jack.
Thanks for the help on the phone, I am getting good readings now.

That prop looks $$$$$$$$ .

I just got off work and plan on finishing the test cell tonight. I am stiffening up the way the rear spars would attach to the rear of the nacelle, closer to the way the finished wing will work. Won't be 100%, but closer than I was.

Thanks all.

DAG
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Old Jan 09, 2009, 09:32 PM
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This is without a doubt the coolest build thread, and one of the coolest models...that I have seen...by far.

Subscribed in a heartbeat.
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Old Jan 09, 2009, 09:56 PM
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Hi Dag,

Just thought I would let you know that I've been following your thread and just can't wait to read the latest installment. Also, I picked up on Hacker USA lending you assistance, so when I went to the AMA convention today I stopped by and spoke with them. You are right nice group of folks. They were very helpful and took the time to explain their product. So I purchased a motor/controller/battery from them and mentioned my purchase was directly related to the help they have been giving you. I like to see companies go the extra few steps to help their customers and feel they should be recognized for their efforts. Now I know there are many companies that do this and a few that don't but I chose to support the ones that do.

Ok done with the soap box, time for another posting from you!

al
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Old Jan 10, 2009, 07:55 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Thanks for all the great comments everyone.

Today I got my airframe support finished. It will hold the plane while I complete the project.

The full power test will be tomorrow as I got my 2 test 4 cell 5000mah today.

One really cool thing I think I figured out after some very crude testing. I hate air retracts, the go up great but most of the time they just plop down at the start then move slower. And when I use a spring assist on my servo operation I really need everything perfect. Well my idea is servo with air assist. I will use the design I have but use a single air cylinder as a assist. When I did a basic test the servo controlled the speed of the operation, and when I put a huge load on the servo the air cylinder did the rest. I will take some pics once I get a actual mock-up done. Another cool thing doing it this way is if my retract battery ran completely dead the air cylinder would have enough to get the gear down and locked.

Thanks, DAG
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