Old Man Mike

I am happy to report a successful Brushless motor conversion for the Draganflyer. The controller board was not modified and I was able to use a standard ESC and Brushless motor combination with a total cost of $30. Along with a few additional components, total cost to convert all four motors will be aprox $230.

As a demonstration of stability, I replaced just the rear motor and flew the DF with three brushed motors and the one brushless motor. Here is a short video showing the conversion:

[link=http://www.af9y.com/BrushlessConfig.wmv]Brushless Configuration[/link]

And here is the demonstration flight:

[link=http://www.af9y.com/BrushlessFlight.wmv]Brushless Flight[/link]

This was my first flight and the only thing different about flying it was that the Brushless Motor starts spinning earlier and stops spinning later.

Tomorrow I will make a quick flight in TI mode to verify that it works with the conversion. I'm fairly certain there will be no problem.

The brushless motors are much more powerful than the brushed motor so I expect to be able to add at least 1/2 pound of payload capability. I have to be careful with this mixed configuration not to take the throttle much above the half way point because the brushless motor begins to overpower the other motors. With a higher power battery, I suspect I could get up to a pound more payload.

And yes, I will publish the design. I want to do a bit more tweaking and change out the other three motors. Plus, I want to keep the tease going a little longer since so many people (including Mike Dammar at Spectro) had said how difficult this would be.

Mike

13BRV3

Wow, tease is right

Seriously Mike, this is GREAT news, and I can't wait to hear more. Good luck with the conversion and testing.

Rusty

msarid

Mike
You are the KING of the DF keep on going
Moti

BB_DF

Congratulations, Mike, that's the Holy Grail of DF hackers! I'll convert mine for sure - maybe it will reduce the electrical noise and help with the drop-out problem. I like the way the BL motor sounds - completely different. The Q4's sound like a swarm of angry bees. BTW I think you only need to set level in Ti mode. I never set it in normal mode and it files fine.

Cheers,
Bruce

VRNowhere

Great job! Please keep us posted.

I don't understand why Draganflyer designers haven't come up with something, since the X-UFO and other European quadrotors are brushless. I've been waiting for some annoucements from the DF guys, but I guess they have no incentive to upgrade their system - darn lack of competition...

Sky High

Great job Mike even though I don't understand how or what you did! Why couldn't you use the existing motor wires? I am absolutely impressed as to how smoothly that brushless motor spins up and how quiet it sounds. Please post more video when all four brushless motors are installed as well as if there is a significant increase in flight time and weight capacity.

As far increased payload capacity, could the current flexible rotors handle a pound of weight without folding? You might have to upgrade to CF rotors with that kind of weight.

Old Man Mike

Sky High: The ESC for the Brushless Motor has to be interfaced such that the fast response time from the DF controller is preserved when mixing the slower pulse information from the receiver. Dammar claimed that this would require a redesigned controller and a custom designed ESC. He said he thought it may be too expensive to market. I'm not sure that he is even working on a new design now but who knows?

About the rotor blades, Dammar told me that they have been tested up to 4 lbs so it looks like there is plenty of margin available.

BB_DF: Thanks for the tip on level setting. Makes sense.

Mike

Sky High

4 pounds?! Are we talking about the same rotors? I'm talking about the black composite and the clear ones you and Bruce are using. Now how do you reckon they were load tested for 4 pounds with a DF that can only lift less than a pound?

Old Man Mike

Yep. That is what he said. I'm assuming he has a test setup to make thrust measurements and that it was not done on an actual DF. I also had to construct a test platform to measure thrust vs current vs rpm when testing candidate motors. I had considered changing the props but it is very difficult to find props which come in both right and left hand configuration.

Mike

Sky High

That would be a sight to see. I just can't see those flexible blades not coning up at least 45 degrees or more trying to lift that much weight.

BB_DF

By "four pounds" he must mean total lift., or one pound per blade. Otherwise he would be talking about 16 lbs of lifting power! So if a blade self destructs when it's stressed with a 1 lb load, then maybe you're looking at 1/3 - 1/2 lb max normal load per blade, or somewhere around 1 - 2 lbs lifting power for a quad the size of the DF. That's actually pretty good, really.

- Bruce

Sky High

Well, if that's how it's determined, then it makes more sense. Zenon told me he has lifted a full drink can with a DF. However, lifting and successfully flying with excessive weight are two different things.

Old Man Mike

I did some outdoor flying today with the brushless modified DF. I am amazed that the DF can fly so well with the mix of one brushless and three brushed motors. In fact, I was able to do a little acrobatics. Here is an axis spin (pirouette):

[link=http://www.af9y.com/BrushlessSpin.wmv]Brushless Spin[/link]

(I had a stationary video camera and used a post processing zoom so the video is not that great)

I also tested it in TI mode and that worked just fine:

[link=http://www.af9y.com/BrushlessTI.wmv]Brushless TI[/link]

After the flights, the brushed motors were quite warm. The brushless motor was several times cooler.

I've ordered all the parts necessary to replace the other three brushed motors since it appears that this design will work. By the way, the motors are able to lift one pound EACH and that is within the constraints of the existing battery and controller. I have not yet tested at that level and will wait until I've converted all four motors before trying to lift any bricks (well, maybe something lighter than a brick).

By the way, I've been warned about people lurking in the forums to pick up ideas for reselling without permission or author credit. I'm not happy to hear that. My interest is in having an exchange of ideas with other DF enthusiasts and not just to be a source of income for anyone lurking in the forums and not contributing. Perhaps it would be best to provide the design information to a more limited group within the forum interested in experimenting with the approach. Not really sure what is best.

Mike

msarid

Congratulations, Mike that is a great info. about the 'lurking�, from my 40 years flying experience if someone want to steal, specially on the internet he will got it so I think that the best way is to ignore them. Again, I am sure all of us happy with your fantastic success, so we are waiting to listen ASAP.(forgive me for my bad English)
Moti

Sky High

Mike, are you just pleased that you're able to yaw 360 period or just because you have a brushless in the mix? That is interesting that not only are you using a brushless with that board but also with 3 other brushed motors.

dmcfirestar500

This is really cool. I so surprised that this hasn't been attempted or atleast hasn't been successfully attempted before. Can't wait to see your DF on 4 brushless motors and I will no doubt convert mine if everything goes smoothly.

Keep us posted

BB_DF

Mike,

You could release the upgrade materials & procedures on an individual basis, as you suggested, to individuals who have demonstrated good faith on the forum, and who would be willing to state categorically that the upgrades would not be used for commercial purposes. That way if someone wanted to violate that trust, the community at large would be motivated to avoid doing business with that individual who had not acted in good faith. However, this is somewhat impractical as it would make a lot of work on your part and would probably also create a lot of bad blood. Remember the old saying, no good deed shall go unpunished.

A more reasonable approach would be to wait until you feel the information has stabilized sufficiently, then create a new thread with a very clear message at the top, something like:

THIS INFORMATION IS FOR INDIVIDUAL USE ONLY AND IS NOT TO BE USED FOR COMMERCIAL APPLICATION WITHOUT THE EXPRESS PERMISSION OF THE AUTHOR.

Having made this declaration it will be obvious on the part of the DF community who is, and who is not acting in good faith.

Cheers,
Bruce

Old Man Mike

Time for a status update:

1) The last of the parts for converting the remaining three motors to brushless should be in early next week. I expect to be able to fly with all four motors converted to brushless the same day.

2) Some additional design changes were finalized. I had hoped to be able to use the default setting of the ESC and although it appears to work, higher power is achieved when the ESC is programmed via a small programming card. The programming card adds about $9 to the cost. Also, I had not included the cost of the heat sinks, pinions and a few other parts in the the original cost estimates. The total will be closer $240.

3) I've started the detail writeup and will post the complete design after testing the remaining conversion. Along with the design, I plan to discuss each of the major components with recommendations for potential changes to improve the cost and/or performance. This is where I hope we can all engage in a collective discussion to iterate the design. I think this list contains more than a few people with engineering backgrounds or specialized fabrication skills. Hopefully this can be an interesting and productive team effort.

4) Next effort will be to add an altitude hold circuit utilizing the Zlog altimeter.

Mike

hiaber

I'm excited about the brushless conversion you have up and coming, but I'm kinda shaking my head as to why DF Innovations has not gotten down to the nitty gritty and come out with a new board including an accelerometer - the Ti is not fool proof by any means, and there are other units available out there now (xufo w/ upgrade, q4 quadcopter etc) that are spanking the DF in flight performance.

Old Man Mike

Mike Dammar is the designer of the Draganflyer and I have a great appreciation for the elegance of his design. Spectrolutions is his company and he is one of the hardest working, most prolific designers I have ever met. Here is just one of his more exotic designs:

[link=http://www.veratech.aero/asx/Animated%20Test%20Flight.asx]Stealth Copter[/link]

It is extremely difficult for a small company like Spectrolutions to compete against the big companies for research dollars and contracts. I'm sure that any time he spends on upgrading the DF design is more because it is his baby than any expectation of significant additional revenue. Depending on the final outcome of this conversion, he might even offer a more integrated version. Don't be too hard on the guy since his primary focus has got to be on the projects that can bring in the dollars.

Mike

Sky High

Mike, I remember seeing that on RCG a while back but it was the real thing. They have a few more videos on their site including a few of the real thing flying. That is truly an engineering marvel. The DF was on the History Channel on the show Tactical to Practical and even made their top ten show. This sling blade would definitely qualify.

Dirk Schooner

This is brilliant news, and if it works even better, it would be great to fly wihtout worrying so much about those poor little brushed motors straining away and getting hot as hell.

Am i right in thinking then that the payload is upped from 4oz to 32oz ???!!!

This is incredible and will revolutionize the Draganfly making it so much better for aerial video.

I have a few more flying hours under my belt now and am getting better at controlling the beast, I put a compiletion of clips on youtube:

http://www.youtube.com/watch?v=06dJhD-IUCU

If anybody want details of my setup/camera let me know (basically a foam block slung underneath with an Exilim camera mounted in it).

Old Man Mike

A payload of 32oz is certainly a reasonable expectation for the brushless motors used. Of course, I cannot be sure until the remaining parts arrive hopefully early next week and testing is complete. I've been working this weekend on how to mount everything so it will not look as kludgy and to optimize the design which eliminated a few more components. I am quite excited to fly it with all four motors converted.

Your videos are most impressive and I will comment further in your thread.

Mike

msarid

Hi Dirk
Very nice movie.
What is the exactly your camera type, casio exilim ex????? and how you setup and function it from the DF.
Regards
Moti

Dirk Schooner

Sorry, I guess I spammed this thread, look at my thread for more details:

http://www.rcuniverse.com/forum/m_6228158/tm.htm

Keep this to the amazing news about brushless motors, it's a revolution and really exciting.