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Old Jun 10, 2010, 02:19 AM
War Eagle!
sneasle's Avatar
United States, AL, Huntsville
Joined Sep 2006
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Quote:
Originally Posted by Draknkep View Post
Ok....

#1..... You already have the program to make the male pug, except that you would have to reduce the outside dimension, by double the thickness of the material to be formed.

#2... why would you need round sheets?? Square works just fine.

#3.... For a female mold, all you need are two steel plates that can be bolted together, with a hole in it the diameter of the spinner back. The material to be formed is bolted between the two plates, and the male plug is carefully aligned and then pressed into it. Yes, you can go more sophisticated, and put alignment pins etc, but if you are careful, it can be done as described.

If you need a radius around the minor hole, then yes, it can be a bit more difficult, but still doable....

I have made end caps for oil tanks for race cars this way, and all I ever had was a 12 X 37" manual lathe, a Bridgeport type mill, and a hand press.

If you have problems with the ones you are making, I can make you Cad drawings of how to do it.

SteveT

Hmm.. I kinda follow you, but I don't at the same time. I get the idea, but I can't visualize how you're implementing it. I don't have enough ME in me, sorry :/.


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Originally Posted by rc_man1 View Post
THe metal ring is very nice... I know it's hard to thin things out on a lathe at 1/8 is just about as thin as you can get before it states to deform... To save the most weight you would have to go with a mold and vacuum a plastic one... But all of this will take time and if DAG his happy with this end produce then that is it.. For me I would make a it out of lite fiberglass and Vacuum bag it so all the extra epoxy would be sucked up in the bag.. Just like we do for the Super Hornet.. It takes a lot of time but if you but a little Kevlar with the cloth it will be super strong but the cost of Kevlar is high... With the press idea does work nicly but you would like to go with a alum in O range then heat treat to a T-4 or above... Something like a 2024-O then press it and then heat treat it to make it 2024-T4 last long time. But like sneasle said it takes a lot to make the molds for it the job.. Sneasle let you Mechinsmates know very nice work... I wish I could help out but all the tools and materals I use are from the Goverment and can not be used for this... Or I would help out.. Uncle Sam would come after me......

Good luck and once agian nice work..

V/r
Mike
Vac molding something is Damon's plan B. I'd love for these spinner backs to work out for him as I think they would add a whole lot to the look, but ya gotta do what ya gotta do, and weight is king for something like this.

As is it would be an extra 4.5oz behind his CoG, it's up to him to figure out if he can handle that. We could probably shave some off, but I doubt it would be enough.

Quote:
Originally Posted by wiltronics View Post
Seven years ago, I manufactured a 40 volt-100 amp ESC that I had a problem with the high current inductive spike from the motor causing the customers to return 20% of the units I made. I never could find a solution that would eliminate the returns so I quite the making them. From my experience, I do not know how they came up with the rule for determing the size of the capacitors to use.
The first rule I found is that all conductors going to the capacitors need to flat and wide. Round conductors had to much inductance. Two, the capacitor leads need to be as short as possible. Long capacitor leads have too much inductance. Third, the power leads soldered to the board need a long flat solder connection. Press the power conductor into a flat bar and then solder it to the copper foil.
The capacitor board you made will not be very effective in attenuating the current spike from the motor due to the use of round conductors. Remember that round conductors are bad and flat wide conductors are good.
The reason I thought the capacitors were too small is that larger capacitors generally have a lower internal resistance than a smaller capacitor. This would make them better at absorbing the current spike. I found that using a ceramic capacitor for each electrolytic used helped in reducing the current spike.

Internal resistance of a cap is a function of many things, but you're forgetting one very important thing.. while capacitance adds with the caps in parallel, their internal resistances are in parallel as well...

That's why 10 100uF caps in parallel will charge and discharge faster then a single 1000uF cap.
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Old Jun 10, 2010, 05:28 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,894 Posts
Quote:
Originally Posted by sneasle View Post
More pictures from the completed 4th prototype. This was the first to be a 'complete' part with the internal boring done.

Dag, would you like me to mail it to you? We don't want to start the other 5 until we know for sure it's what you want.

edit:

Part weights 2.75oz in it's current form. That's with a 1/8" wall. That's heavier then you wanted................

Not sure if we can thin the wall enough to take 3/4 of an oz off without causing issues.
Very cool.
2.75 is a bit high, but my be doable. The Tru-Turn spinners I have are less than 1/16" and do not deform, so that will not be a problem, but you may have a problem doing that in you machine. I really think before you put to much of your time in it I should trial fit it, and test it on my mock-up.

That is incredible work, and what a great job.

Thanks, Damon
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Old Jun 10, 2010, 05:37 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Right!
Here is how the ESC will be in the nacelle. And I will show pics later.

I know from the manufacture that I can have 10" between my battery and ESC. My ESC has about 4.5" of wire on it. Not enough to really help get my ESC plug out to where my battery will be in the leading edge of the wing. But if I mount the ESC at the front of the air-intake and make the ESC lead 9", and my battery lead 1", then I can just add ESC to motor wire. My longest run will be 26", Last year I tested at 60" and with the fan had no shut down of the ESC. In this set up I won't need to add any extra caps, and will have very good airflow.

This is why scratch building takes so long, I now have over 13 hours in this system, and now feel I have it licked.

I will post pictures tonight.

Thanks all,
Dag
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Old Jun 10, 2010, 05:54 AM
Old Submariner
United States, WI, Milton
Joined Dec 2007
577 Posts
Sub-Spinners

The sub-spinners could be very easily made by spinning them.

Make a hardwood mandrel with the sub-spinner detail turned on the end including overrun in depth to provide extra material to cut out mounting ears.

Drill a hole thru the mandrel end to end and run a piece of all thread thru it, clamp a piece of spinning (soft) aluminum on the end of the detail end with the all thread and large fender washer and nut.

Place the whole thing in a three jaw chuck on a lathe, use turning speed of approximately 1500 RPM and start forming the the blank down over the mandrel using a piece of hardwood dipped in cutting oil.

These would come at virtually no weight- maybe 1/2 ounce.

Does anyone remember "MOON Hubcaps" ?

Tom
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Old Jun 10, 2010, 06:18 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
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Quote:
Originally Posted by teeceeveecee View Post
The sub-spinners could be very easily made by spinning them.......etc etc Tom
Isn't that how they make saucepans?
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Old Jun 10, 2010, 07:13 AM
Old Submariner
United States, WI, Milton
Joined Dec 2007
577 Posts
Exactly So !

Quote:
Originally Posted by Colonel Blink View Post
Isn't that how they make saucepans?
You are 100% right Colonel, very simple and very cheap.

There are of course stamped units. To stamp something is certainly less labor intensive but it requires a heavy press and expensive die sets and special alloy metals.

Dag is very concerned about weight, and rightly so. Spinning would meet all of his requirements, and I notice in background pics of the 36 he has a drill/mill/lathe unit so he could fabricate them very simply.

Best,

Tom
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Old Jun 10, 2010, 08:41 AM
ONEHANDRC
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United States, WI, Genoa City
Joined Dec 2007
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I watched Cessna & Piper spinners being 'spun' many years back when I worked at Wag Aero. Very quick, simple process once the 'male mold' is made.
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Old Jun 10, 2010, 08:54 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,894 Posts
Like this:
metal spinning (wyoblanie) (2 min 38 sec)


Dag
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Old Jun 10, 2010, 09:06 AM
ONEHANDRC
gallfer's Avatar
United States, WI, Genoa City
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Exactly! The material used was very soft which made the process easy, but the finished part was not very durable. But it was 'cheap'.
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Old Jun 10, 2010, 09:23 AM
3.14159265358979323846264
rccardude04's Avatar
Wichita, Ks
Joined Jun 2005
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Quote:
Originally Posted by gallfer View Post
Exactly! The material used was very soft which made the process easy, but the finished part was not very durable. But it was 'cheap'.

That's what the quench/temper oven is for.

-Eric
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Old Jun 10, 2010, 10:40 AM
War Eagle!
sneasle's Avatar
United States, AL, Huntsville
Joined Sep 2006
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That is an option, but not one I see them letting me try in our machine shop.

Spinning the part out is what I would suggest over stamping as I think there are more hidden monsters in trying to stamp.

Ok, so mail it up to you Dag? Send me an addy and I'll try and get it out tonight.
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Old Jun 10, 2010, 03:59 PM
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Quote:
Originally Posted by dag214 View Post
Very cool.
2.75 is a bit high, but my be doable.
Maybe this is overly simple, but how about using Sneasle's machined part as the plug for vacuforming the pieces you need.
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Old Jun 10, 2010, 07:44 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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Quote:
Originally Posted by j32driver View Post
Maybe this is overly simple, but how about using Sneasle's machined part as the plug for vacuforming the pieces you need.
As the machined part, is "to size", the vacuum formed part would be over-sized, by twice the thickness (in diameter) of the material used (in other words, the thickness of the material all the way around)

Sneasle....

As to press forming without a full female mold.... Think of a sheet of latex that you push your hand into, it will form around your hand but not go into the "valleys" between your fingers etc...in this case, unless you were going to put a radius on the minor diameter, you don't need it. (and as noted that can still be done, without a full female mold, by machining the radius onto the male "punch" and having a recess, then positioning a piece of round bar stock, that would push into the recess. This does take some alignment pins in all pieces, but again is still not really all that difficult. (remember...don't "over-think" it )

SteveT
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Last edited by SteveT.; Jun 10, 2010 at 07:53 PM.
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Old Jun 11, 2010, 05:20 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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What I got done last night.

I am 99.9999% sure this is it.

I feel good enough about this that I am going to make the Velcro mounts, and trim away a bit of wood in the nacelle to make sure there is room for the fans. Then plank the nacelle and get moving again. When I test the system if I see my ESC runs cool, then I will remove the fans. I just want to make sure I design in the option if I need them.

Rock On!
Dag
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Last edited by dag214; Jun 11, 2010 at 08:23 AM.
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Old Jun 11, 2010, 07:35 AM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
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Quote:
Originally Posted by dag214 View Post
What I got done last night.

I am 99.9999% sure this is it.

I feel good enough about this that I am going to make the Velcro mounts, and trim away a bit of wood in the nacelle to make sure there is room for the fans. The plank the nacelle and get moving again. When I test the system if I see my ESC runs cool, then I will remove the fans. I just want to make sure I design in the option if I need them.

Rock On!
Dag

LoL

Picture 3 - Nice Piggies!
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