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Old Oct 13, 2012, 05:06 PM
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United States, CA, San Diego
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Originally Posted by 13brv3 View Post
I'm glad to read comments about what the kits should contain, so thanks

The minimum I can see is a kit with only the G10 and Delrin that I cut. Maximum would be a fully built, ready to fly gimbal. Everything in between is somewhat negotiable, but I plan to stock everything in the kit with the possible exception of servos, depending on whether I can get them below retail.

Cheers,
Rusty
That would be good. I definitely think servos can be a user sourced part . Pulleys may also need to be a user sourced part unless you can stock a few different options.

Do you have a time frame when you will be offering this.. like before Christmas ?
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Old Oct 13, 2012, 05:13 PM
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Hawaii
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>>Do you prefer the MKS or high-end hitec's more?<<

I really have no preference right now. I have tried three different MKS. Two of them with external pot. I have also tried a handful of HiTec high power servos. The MKS' seem a bit smoother but lower power and about the same speed.

The only time I can tell the difference is when I use a 90 degree MKS versus a 180 degree on the roll axis. The 90 degree MKS is definitely smoother which makes sense.

On tilt it is still hard to tell. There are a lot more testing to be done. I do like the HiTec on tilt with external pot because of 2 reasons. 1) Servo City will take the pot off for me. 2) Some MKS have glue on the servo case which makes taking out the pot very risky.

>> On paper the hitec's seems to be better in most areas except deadband which is apparently adjustable (not sure if it can go any lower than 0.002 micros).<<

That's where I tend to disagree with Gary. I don't believe dead band makes that much difference in the smoothness. I really don't think we can tell the difference between .001 micros versus .002 micros. Yes in theory it may make a difference but there are so many other variables in reality. Just as I mentioned before I only tested the HiTec servos on roll at 180 degrees travel and MKS on roll with 90 degrees travel so that pretty much negate any deadband differences.

On the tilt with external pots I really doubt the deadband makes any difference at all.

>> I know gary and andrey prefer the MKS through all of their testing, which is making me lean towards the MKS.<<

Andrey and Gary tested way more than MKS servos. They just like MKS the best because of the performance and maybe Gary has dealership for them.

>>What's the travel on the standard MKS (no ext pot)? I am guessing 120 deg?<<

90 degrees and non-adjustable. That's why the MKS is good for the roll axis if you don't plan to use a lot of travel.
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Old Oct 13, 2012, 05:19 PM
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Rusty I too would rather buy your complete kit minus servos even if I did plan to build something later myself. Just in case I never get around to whipping something up you know
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Old Oct 13, 2012, 05:21 PM
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Hawaii
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>>I hope that the kit will have an option for supply of pulleys, belts etc, unless these components are easy to source from another supplier who ships internationally with fair freight policies.<<

Exactly. I can sure sympathize. For that matter I have a hard time with freight cost living in Hawaii. I have to ask friends to purchase supply for me on the US mainland and ship them to me to save on exorbitant freight costs.

The belts, pulleys are fairly easy to source if you live on the US mainland but probably fairly difficult if you are international. That's why I believe Rusty is a good source to try and keep an inventory. Also Andrey (askman) uses the same items for his gimbal and he has an inventory. That should be a very convenient source to purchase.

>>So a plea, can there be an option for a Ready-to Build or Almost-Ready to build kit. IE stuff like bearings, pulleys, and belts, fixings etc IE everything less servos. I understand why a re-seller may not want the potential head ache of returned faulty servos.<<

I can foresee Rusty supplying the G10 plates, Delrin blocks minimum.

Then have a couple of different small pulleys for different servos and a couple of different big pulleys for different ratio. I think the ratio will be 2.8 to 1 and 3 to 1. Then a couple of belt length for different size gimbal.

If he can source out bearings I am sure he will provide bearings and hardware as well.

I think he may be even thinking about tubes. It all depends on the quantity and price.
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Old Oct 13, 2012, 05:22 PM
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Originally Posted by pug398 View Post
Rusty I too would rather buy your complete kit minus servos even if I did plan to build something later myself. Just in case I never get around to whipping something up you know
Me too!
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Old Oct 13, 2012, 07:11 PM
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Originally Posted by jcmonty View Post

Do you have a time frame when you will be offering this.. like before Christmas ?
Before Christmas should be a safe bet, particularly since you didn't mention what year

Seriously, this takes way longer than most people realize. It's easy if you just want to put one together to use, but if you're trying to make the best choices for the most situations, there are a LOT more options to consider. What I never want to do is start to sell something, then have to change it 5 times in the first month, because then I can't necessarily know what anyone got with their particular kit.

All that being said, I have the first prototype assembled, though I've taken it apart and changed things about 5 times in the last couple days. Before I can even flight test it, I need to stop making major changes. I'm hoping to get this one in the air tomorrow, but no guarantees. I've already got a list of things to order to try for the second prototype, so I wouldn't expect to see a kit for a couple weeks.

Rusty
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Old Oct 13, 2012, 08:46 PM
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The digital servos I have on hand are 180 degree servos. Since the tilt drive ratio is 2.8:1 (90/32) then that would translate to ~62 degrees rotation or +/- 31 degrees if the pot is kept internal. Does keeping the pot internal seriously affect the operation other than limiting the rotation of the tilt? Know this has been talked to death in older threads but trying to save some reading and will smack myself on the hand for you
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Old Oct 13, 2012, 09:05 PM
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Originally Posted by SeismicCWave View Post
Andrey and Gary tested way more than MKS servos. They just like MKS the best because of the performance and maybe Gary has dealership for them.
All the servos we tested were bought at full retail, just like everybody else. When we decided to try the Hyperions I was able to get a dealer arrangement for them, but then we found they had horrible quality control problems, and I had to eat a big pile of these (I still have about 30 of these POS units... ). From the getgo, I was never thrilled with the performance of any of the Hitecs, even the uber-expensive 7940TH. One of my 3D heli buddies recommended the MKS servos, because he found them to be ultra smooth and repeatable, for his 3D flying. My LHS happened to have some, so I tried them. I was blown away by the difference in smoothness, so at that point, I worked out a dealer arrangement with the US distributor, but that's only if I buy them in quantity.

This hasn't stopped us from continuing to test different servos. We found some from a Chinese company called Lontair that have similar performance to the BLS950, and use a unique magnetic encoder instead of a pot. We are trying to get them to do a special version of this mag encoder servo that will work over a wider pulse range (500-2500uS vs the standard 1000-2000uS...), so that we can get a greater operating angle without having to resort to an external pot. The advantage of doing this, instead of just using a 180-degree modded servo is that the latter approach cuts the resolution in half.

In a parallel effort, I am having the factory do a run of BLS950s with the external pot mod. I have to buy a big quantity of these, so I will definitely make these available to whoever wants them. This doesn't mean we have stopped looking at servo options, quite the opposite actually. One path we are definitely exploring is doing our own direct-drive setup, using some special pancake-type motors.

Anyway, it doesn't surprise me that many can't seem to see a difference between the MKS servos, and something like the Hitecs mentioned. The reason is that unless you have a dedicated gimbal controller with an output rate that is at least double the servo's rated update rate, it might be harder to see the difference in smoothness. I guess we will just have to agree to disagree, but I have clearly seen the difference with my own eyes.

-- Gary
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Old Oct 13, 2012, 09:16 PM
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Navarre, FL
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Prototype #1

Since the natives seem restless

Here's a picture of the first prototype as it currently exists. The camera tray is set up for a 4 inch wide camera, but the overall yoke is large enough for a 5.25" wide camera if I cut off the shafts and changed the tray. Of course it can be sized for any camera within reason. There's still 20 grams to be saved by swapping the remaining SS hardware for aluminum. I'd bet a GoPro sized version could be under a pound

Cheers,
Rusty
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Old Oct 13, 2012, 09:24 PM
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Originally Posted by 13brv3 View Post
Since the natives seem restless

Here's a picture of the first prototype as it currently exists. The camera tray is set up for a 4 inch wide camera, but the overall yoke is large enough for a 5.25" wide camera if I cut off the shafts and changed the tray. Of course it can be sized for any camera within reason. There's still 20 grams to be saved by swapping the remaining SS hardware for aluminum. I'd bet a GoPro sized version could be under a pound

Cheers,
Rusty
I am looking forward to seeing the flight videos on this version. Hopefully you won't have any flex issues.
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Old Oct 13, 2012, 09:36 PM
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Originally Posted by Xnaron View Post
I am looking forward to seeing the flight videos on this version. Hopefully you won't have any flex issues.
It's pretty darn stiff, so I can't imagine any problems with flex. I left it larger than it needed to be just to give it more of a chance to flex.

The biggest challenge will be remembering how to fly it

Rusty (too busy making stuff to fly)
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Old Oct 13, 2012, 09:40 PM
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Originally Posted by pug398 View Post
The digital servos I have on hand are 180 degree servos. Since the tilt drive ratio is 2.8:1 (90/32) then that would translate to ~62 degrees rotation or +/- 31 degrees if the pot is kept internal. Does keeping the pot internal seriously affect the operation other than limiting the rotation of the tilt? Know this has been talked to death in older threads but trying to save some reading and will smack myself on the hand for you
No ill effect besides limited travel range.
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Old Oct 13, 2012, 09:47 PM
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Originally Posted by 13brv3 View Post
Since the natives seem restless

Here's a picture of the first prototype as it currently exists.
I am amazed you got it under 500 grams. So if you save 20 more grams with the aluminum hardware and add back a bit of weight on the mount you should be right at 500 grams.
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Old Oct 13, 2012, 09:52 PM
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Originally Posted by Xnaron View Post
I am looking forward to seeing the flight videos on this version. Hopefully you won't have any flex issues.
The whole idea behind this build is to make a super rigid gimbal. My first attempt with the carbon tubes was 730 grams. The second one with 1/2" square aluminum tubes was 577 grams. Now Rusty using 10mm square tubes actually managed to bring it down to sub-500 grams and still retaining the rigidity.

The only flex will come from the vibration isolation.

The video quality will reflect more on the gimbal controller than the gimbal.
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Old Oct 13, 2012, 10:02 PM
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>> I guess we will just have to agree to disagree, but I have clearly seen the difference with my own eyes. <<

I agree. I disagree about the deadband issue not because I don't believe your eyes. I am sure you have every reason to believe that the deadband is an issue. That is because you have done a lot of testing and various equipment and you are using different gimbal controller. I am not prepare to buy a HoverFly Gimbal controller until they come out with a 2 axis version. In the meantime I believe there are a lot of people out there that is not ready to buy a HoverFly Gimbal controller yet and there is no reason for them to stop having a stabilized gimbal with their flight controllers.

My point really is that for some one using a flight controller as a gimbal there really isn't much difference when you compare all those high end servos.

Yes, I am still using a Lontair MIBL servo on one of Andrey's gimbal. Plus I still have all those Hyperions and Hobby King servos that didn't work quite as well as the MKS. I even modified a MKS mini servo with an external pot for fun.
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