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Old Apr 04, 2015, 11:09 PM
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Xtreme Power Systems
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Large fans safety thread

Since this thread discussing safety was closed:

http://www.rcgroups.com/forums/showthread.php?t=2367569

.... I wanted to continue with discussing building safe and reliable test setups. I will be adding pictures of our test setup that we have used over the years to test dozens of different fans.

Fans are not toys. Building test stands made of wood, held down with C-clamps, screws, or other temporary holding devices is something that you should never do!

Some simple rules to follow running up a fan either on a test stand or in an aircraft:

* NEVER stand to the side of the fan. When a fan explodes, it will come apart out the sides due to the inertia, and debris will go forward, so always stand behind the fan.

* NEVER run a fan that is not balanced. If a fan makes an odd noise (harmonic) at any RPM, it's out of balance. You shouldn't try to "run through" the vibration. Fix it!

* NEVER run a ESC or fan motor beyond the manufacturer's specifications. Manufacturers have some headroom in their systems to allow safe operation. Deliberately exceeding specifications can result in explosion of the ESC and/or fan.

* NEVER touch the exposed leads of a battery system exceeding 40 volts (10S or higher). Somewhere between 40v and 50v DC can stop your heart if you touch the positive and negative leads simultaneously.

* ALWAYS tie the 3 motor wires together and secure them so they can not become disconnected. If any of the wires disconnect while running, a controller fire and/or fan explosion can occur.

* ALWAYS check the inlet before starting up the fan to make sure there is no debris. A pebble, bee, piece of wire insulation, or even a piece of tape can FOD the fan and blow it up.

In high power setups, make sure that the exhaust ducting is secured properly. We have put together systems with right at 30 pounds of thrust and 400MPH of efflux. That kind of force can rip apart exhaust ducting that is rolled, so make sure you using the proper exhaust tubing for your setup.
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Old Apr 04, 2015, 11:09 PM
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Here are some pictures of our test stand setup that we use for testing fans of all sizes.

The batteries can be left on the stand (velcro'd in place) because of their position, but can also be placed in a hanging assembly that fits over the right side pull-handle.

The polycarbonate ballistics plastic started out as a 4' x 3' sheet of flat plastic and was heated in a special oven and then bent into a U shape to match the width of our test stand. The plastic is crystal clear, allowing the laser tach to be used through the plastic shield with no change in accuracy. The strain gauge has an electronic box to show the peak and average thrust.

The wheel locks work, but you have to run this on carpet - it slides with more than 16 pounds of thrust on the epoxy floor.
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Old Apr 04, 2015, 11:51 PM
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All good rules ....about the same working around jets at work.or start carts and apu's stay out of line with the turbine wheel.that's why early jets have a red strip painted on the fuse where the turbine wheel is located.
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Old Apr 05, 2015, 02:53 AM
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Good Info Jim. You can't be too safe.
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Old Apr 05, 2015, 03:43 AM
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Quote:
Originally Posted by JimDrew View Post

We have put together systems with right at 30 pounds of thrust and 400MPH of efflux.
No video, it never happened. If you want your thread to have any credibility, dont start out with BS in your first post Jim.

You've been claiming that kind of stuff for years. There's not one video to back up your claims. Why is that?

Feel free to post my videos to show how to not do it. But, make sure to post the whole video though, including the part where it shows $100 fan/motor combos doing 25lbs+ thrust and well over 300mph efflux.
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Old Apr 05, 2015, 03:46 AM
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BTW I closed the other thread , which was a fan performance thread, not a fan safety thread, becasue you were dogging the thread with your safety agenda. So, now that you have your own thread, do you think you can leave my threads alone? I'd really appreciate it.
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Old Apr 05, 2015, 03:59 AM
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Quote:
Originally Posted by efflux RC View Post
Good Info Jim. You can't be too safe.
That's a heck of a nice rig Gary. If I was in the business of selling fans and equipment, I hope that I would have something that nice too. It looks like you have covered everything, even a safety box housing the exhaust area. You can obviously run that with an audience in close proximity. That is a worthwhile investment for a business like yours, and all of the costs can be taken off the bottom line. It's definitely not the kind of thing that the average edf guy is going to have in his shop though. I'm sure that you understand that. Jim, however, doesn't seem to understand the difference.

BTW, I would have used Jim's rig as an exexample, except................oh, there are no pics
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Old Apr 05, 2015, 10:00 AM
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Well I have seen Jim's test stand so I know he has one
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Old Apr 05, 2015, 10:04 AM
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Here is the one I have and use. This is the very same one Jim uses too. This is a display at an event an AZ several years ago. During testing I have a clear shield that goes up on the side I stand to protect against parts blowing up Only had large one do that when I lost commutation and the fan rotor struck the side of the housing and blew 9 of the blades off!! Then the unit was so out of balance it just blew the housing apart. It was kinda like watching the NHRA and seeing a Top Fuel motor blow up. Crap everywhere! I have other pics too but I lost a hard drive and didn't have it all backed up....


This stand was a very generous gift from XPS for my use in testing and winding motors for the project we were working on
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Old Apr 05, 2015, 10:44 AM
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When I get back into my office, I will post the pictures of the setup we use for testing fans. Notice the 2nd post where it says "reserved for pictures".

Just because we don't post videos of events does not mean the events do not occur. I certainly don't want just anyone running any fan system (ours, Schuebler, Stumax, etc.) at power levels above 12S without having a lot of knowledge and respect for safety. I have deliberately not sold a few fans to people who were clearly not capable of understanding the dangers. I guess I should rate our fans as 125+, as in 125 or higher IQ to use them. We have only posted a few videos of 15S setups (installed in aircraft) because I don't want some backyard knucklehead trying to duplicate what we are doing. I don't need the liability, but for me personally it is a moral issue.

I don't care if you make a $50 fan system with 100 pounds of thrust. We haven't sold fan systems in several years, so there is no competition to me. I (as do many others), believe it is incredibly irresponsible to show testing done on a setup that is clearly unsafe. If someone duplicates your test setup and is injured you likely won't care until the legal issues arise, and maybe you don't care about that either.

This thread is about fan safety. Please have a happy and safe Easter.
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Old Apr 05, 2015, 10:56 AM
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Nothing wrong with a wood test stand if done right. The one we use is a monster, we mechanically tested it up to 55lbs first before putting a fan on it! It is made out of quality hardwood and is more than mechanically sound! I tested a K140 on it and pulled 34lbs on the stand no problem. Now ours is done right but most wood ones I have seen don't seem very safe...... At the same time I only test sound fans (shubi, stu, tam,dynamax,turbax and now the jetfan) I'm not a fan of testing home brews, that is where I believe most incidents happen...)
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Old Apr 05, 2015, 12:38 PM
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Quote:
Originally Posted by JimDrew View Post

Just because we don't post videos of events does not mean the events do not occur. .
Well, that may have been true 5 or 6 years ago, but these days, if there's no video, then it didn't happen. And, if this thread is all about safety, then why are you making performance claims in the very first post? Do you assume that it give you some kind of credibility? It might if you weren't so well known for making unsubstantiated claims.

I've been on these forms since before you marketed the XPS. unit, which was just a refined version of what Racer1 was doing with Dynamax and outrunners. He was a back yard innovator. His work launch a whole group of imitators. You were just one of many.

Post all the saftey guidelines you want. But when you make false performance claims, ill be here to keep the record straight.
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Old Apr 05, 2015, 03:47 PM
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Old Apr 05, 2015, 04:54 PM
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Safety is Paramount

My favorite videos were Jim's team's Starfire/15S Dynamax breaking 220 mph and the one where a team member is trying to hold on to a twin XPS Dynamax Eclipse on runup - scary power...

I was a member of a team that developed one of the first Ballistic Recovery Systems - a rocket-deployed parachute that brings the whole airplane down. Years later that system saved my life after I forgot to install a critical safety pin on the elevator control horn-to-pushrod connection, and that connection vibrated apart at 3000 ft. Yet, as far as I know, I and one other pilot out of 200 at our airfield have one of these systems installed. Yeah, they start at $3500, but is that what your life is worth?

We made the rocket test cell out of 3/8 Lexan/ steel frame, and the thrust sled looked a lot like Gary's unit above..
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Old Apr 05, 2015, 06:45 PM
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Yeah, pretty much, it is what it is, lol.

One thing more. I guarantee thatif there had been any mention of 50lbs of thrust and 400 mph efflux in the last 8 years I would have been all over it, cheering you on Jim.

Show the post or the thread where those claims were even made, let alone proven with video or witnesses.

It never happened! Where do you get off, making these ridiculous, unproven performance claims??

They have therapy and medication for delusional, narcissistic, behavior. Maybe you should check it out ..........
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