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Posted by askman | Nov 29, 2012 @ 05:54 PM | 15,613 Views
well, It seem like I've been getting this question asked a lot recently with release of my new AP/AV multicopter frames. So I want to spend some time today to discuss the consideration for deciding what size multicopter frame to choose.

When I began my multicopter journey, I started out with spectrolution board. it was first "Affordable" controller at mere 450 bucks and came with 3 axis of gyro and thermal levelling system (similar to fma copilot . OMM (oldmanmike) was using small outrunners with 10" epp props and I was one of the first to use dt700/750 in multicopters. Since we were mostly doing still photos and crude video, the airframe was very simple and crude by today's standard.

fast forward 4 years and now, multicopters have become ubiquitous. With all the variety of choices, it has become more confusing to choose, so I wanted to share some basic criteria.

Much as Hexacopter has been popular in US (this due to certain reasons that has to do with availability of small motor and props more than anything) we find coaxial type of multi does much better in windy situation. In general, quad is no worse than hexa in most cases and cheaper. While lightely loaded hexa will offer some protection against motor outage, this is rarely the case in AP. Also in general, bigger disk area means worse wind performance. That is why we have settled on quad, y6 and x8(both coaxial) form of multi as being ideally suited....Continue Reading
Posted by askman | Oct 02, 2012 @ 10:36 AM | 16,806 Views
It seems like I've been answering lot of question about Jello lately, so, I want to put some basic primer on vibration control today. There is NO EXCUSE to have jello or vibration in your AP/AV multicopter and if you have it, you need to kill it and it all starts at the Source.

PROPS: Lousy balancing of props are the biggest cause of Jello. Cure starts with high quality props and good balance job. here is a good video on prop balancing: I know some prop makers say their props are prebalanced. well, may be good enough for Nitro plane, but not good enough for AP/AV.

prop balancing video tutorial (5 min 5 sec)

In general, larger the prop, more critical it is to balance the prop in both blade, tracking and hub. I've found that sub 10" props are much easier as hub balance gets less critical, but most AP/AV setup requires larger prop. Even Graupner props will need some work in balancing, but usually less so. Why lot of graupners gets used in AP. APC props are notorious for poor hub balance and requires lot of work to get them to perform well. Even my favorite zingers requires balancing (but easier since I can sand down the wood ) Invest in good balancer and learn to balance your props. I've been selling lot of zingers for multicopter AP use, as they do really well in wind flying. not the most efficient, but very stable. I would avoid cheaper nylon props. In general, EPP props are lousy for AP/AV. heck, I don't even...Continue Reading
Posted by askman | Aug 31, 2012 @ 01:31 PM | 14,447 Views
well, we have come up with budget and idea about what we want to achieve with AP/AV. Now, it is time for multicopter selection, and setup.

Now, if you have never flew RC, stop here and go buy yourself a AR drone or Blade MQX as welll as copy of good simulator. get comfortable flying the blade MQX before venturing further. This is good advice if you don't have good RC flying skill and it is stress free way to ease into multicopter.

If you are ready for first larger multictoper. I would recommend F450 frame. ARF kit is affordable way to get into the first serious multicopter. Combined with naza, it makes for good starter ap/av setup.

For AP/AV controlling vibration is paramount to success. Good quality motor and props are very important in fighting vibration.


the downside of DJI kit is the quality of the motor. The qc has gone down IMHO from early production, so sometimes you can get motors that cause bad vibration. If you'd rather have an alternative motor, I would recommend sunnysky 2212 /920kv or better yet 2216-800kv motor as alternative replacement, but only after you are over the initial crashing phase. DJI motors are easy to replace and commonly available and can use upto 10" graupners or 9" zingers on 4S . . 2216-800 will turn upto 11" graupner or 10" zingers and on 4S, that is lot of thrust. For cheaper prop. use 8" dji with lighter load practicing....Continue Reading
Posted by askman | Aug 23, 2012 @ 07:14 PM | 18,113 Views
instead of continuing my AV/AP beginner series, (which I will continue after this brief interlude) I bring you a How to article on modifying the BLS 950 servo for external potentiometer. Now, almost all higher end servo shares common trait, so you can use this article for them with appropriate changes for design percuilarity.


now, if you want to turn this into 360 continous servo instead of external pot, you don't have to cut the potentiometer wire. you need to remove the mechanical limit pin and the plastic pot turner off the bottom of the main gear. center the potentiometer and reassemble. that is all you need to do....Continue Reading
Posted by askman | Aug 07, 2012 @ 11:31 PM | 14,284 Views

now, you understand that there is no free lunch and you have made good assessment of where you want to go with AP/AV. I kinda went over this in TANSTAFL , but we will go more into details in setting realistic budget.

First. assess what you have. Radios, Camera, etc. most people do have some of the items that you will need, and while it may not be ideal, it will get the job done. This is especially true for cameras.

rule number1: forget DSLR. I know people love their DSLR, but until you are ready to risk several thousand bucks everytime you fly, forget it. In fact, Best place to find a good camera is probably in your drawer.

Don't think you have to have latest greatest camera. Just because you saw someone posting great video or still from such and such cam, it does not mean you need the same to get good result. For example, I've been using Panasonic Lumix GF3 as my test camera. I got it off ebay and amazon (2 of them) for bit over 300 bucks each with 14mm pancake lens. this is about same price as gopro hero, but output is far superior. This does not mean gopro is a bad cam. in its case, it is nearly indestructible and produces very much usable video. I just needed something in Nex5 class without the tariff. Nex5 with 16mm would cost almost double that and with hacked firmware, the video quality is quite good off GF3. I would say superior in some cases to Nex5. for my use, I did not...Continue Reading
Posted by askman | Jul 17, 2012 @ 04:05 PM | 14,877 Views
as many of you know, I mostly hang around multicopter forum. Multicopter is latest platform and very popular one to hang camera on to. With technology advancement in gyro and automated flight, multicopter has become to platform to have. anyway, today is all about basics.

now, I've seen lot of post that goes like this.
hi, I am new to multicopter, I think it is great, never flew anything in my life, but I want a multicopter since I saw it on XX and I see the potential to make me rich and famous. my budget is $500.00 and I have several requirement.

1) I need controller with GPS and waypoint programming.
2) need FPV gear (i've done lot of computer flight sim, I know how to fly fpv)
3) I need it to be large enough to carry my D5 but gopro is fine for now.
4) I need fully stabilized gimbal

now, I know that many of us are excited to jump right in, but before we start any endeavor of this magnitude, you really need to consider what you are really after and assess your situation. In general, you really need to assess why you are interested in AP/AV.

For many of us, it is just cool to take video and picture from the Air. Most of us really are not out to make a living taking pictures though, beyond doing an occasional job for friends and family. (usually for little or no compensation) There are professional AP/AVers though. Most of them started as either accomplished Photo/videographer with some rc...Continue Reading
Posted by askman | Jul 03, 2012 @ 03:32 PM | 14,884 Views
well, I get a lot of queries about various things related to AP/AV as well as multicopter, so I decided to distill it down to this entry. In realtiy, the answer is TANSTAFL. So, that is the theme of this blog. If you are a reader of Robert Heinlein, you will recognize this term from the novel "moon is harsh mistress" It means "there aint no such thing as free lunch" and this really fits my answer. With new technology and competition, the price of things are dropping, but this rule wills still remain true in every aspect.


I will include redundancy into the reliability as well. In general, simpler the system, more reliable it is. but also, component selection can also make a difference.

Design consideration: design like Y6, Octo and x8 also has some redundancy in case of motor/esc/prop failure . So for best reliability, you want tri/quad, but you are trading off possible redundancy of other design. More motor means more weight and more things that can go wrong. Coaxial design also loses some efficiency. So in many ways, you are trading flight time and cost for reliability.

component selection: selecting a good quality motor that is large enough to handle the load is very important. don't try to save money on motors. it is not worth it. ESC wise, I prefer 30amp as minimum with N-fet design. luckily, you can get simonK flashed n-fet esc for good price, but serious guys will...Continue Reading
Posted by askman | Jun 29, 2012 @ 07:26 PM | 14,845 Views
if you've been following the thread on AG gimbals, you probably know that i am a proponent of Y and to lesser extent Quad for multicopter for AP. While I realize this put me in the minority, I find that for best flight performance in windy condition, Ys are hard to beat. to gain that benefit, you do lose bit of efficiency, but I think most of us are willing to make that trade.

Gary has been asking about the Y conversion kit for a while. he has shrimp and crab kit that he has to put together, but just never had the time, so he just wanted to convert the F550. when Bobolavega showed up with his conversion of both 450 and 550, I had to build one. I just created a simple motor mount conversion and that is all it took (you also need to take it apart and rewire it, but that is pretty easy on F550)

anyway, here is the pic and first good video from the gimbal that is on it.

Y550 test5 (3 min 32 sec)

I am still working on fine tuning it, but pretty happy with current result. To be honest, Shrimp is still better in stability due to compactness of the system and simonK flashed esc, but I am pretty happy with the result so far. but that also makes this an ideal platform to work out the improvements on.

Now, I get lot of question about gimbal controller. Currently, I test using controller built into naza, and HF gimbal controller. so, lets go over the list of available gimbal control solution.

1) DJI WMK : GPS lock...Continue Reading
Posted by askman | Jun 24, 2012 @ 08:53 PM | 16,271 Views
well, back to more prop talk. :

on my last update on april 30s, I've posted about gemfan cf mix prop failure. it happened again in AP use. so, I will put notice that it is not recommended to be used. The gemfans have also released some CF copy of graupners. biggest issue from what I've been reported has been QC issues. for how much they cost, they seem to have issues with hub being not consistent.

so, which are the best props for F450/550? or AP in general? well, Graupners are still favored by many, but I am having great result from using zinger wooden props.

Zingers have lot of pusher prop available, and 8x5 and 9x5 combo has proven to work as well or possibly even better than graupners in windy situation. graupners are still bit more efficient though. They do need to be balanced and bored for dji motors as they are 6mm standard bore. but they fly great.

now, some of the later batch of DJI motor (2212) seem to have vibration issues as well. on one F550 kit., I had 3 motors being unusable for AP. Earlier kits were fine, but not these. I've heard that DJI has since changed the motor once again. (etched instead of sticker logo with issue that graupners will not easily work without spacer now) dynamic balancing can help a motor, but I am finding that we cannot do it accurate enough for AP use. in another word, if you have to dynamically balance a motor, just replace it if you are going to use it in AP/AV. you can make it great for stick banging with dynamic balancing, but not for AP. this lead to another view in that you should always buy decent quality motors.
Posted by askman | Apr 18, 2012 @ 08:40 PM | 14,431 Views
well, I got my gemfans. they are nice blade. very well suited for DJI 450 and 550. you do need to drill out the hub. hub diameter is similiar to DJI blade, but with carbon reinforcement, the blades are much stiffer and should be stronger. I used step drill to get it close and reamed the bore hole to .3135. tight fit on the motor. they needed very little balancing, and it was ready to put on.

One thing I noticed about puttng on the new blade were that my 450 and 550 both were bouncing around more in the wind. they were no longer solid anymore.
so, I did a quick and dirty experiment to determine the cause, most obvious being the diskloading.

my 450 were at 1.5kg, and 550 were at 2.6kg. both with 8" and flew well in wind. this is about 200sq in and 300 sq in disk area. 1.39sqft and 2.08sqft leading to 38oz/sqft and 44oz/sqft. both flying very well.

with 9" blade, same weight, my disk area is now 254sqin and 382sqin. 1,76sqft and 2.65sqft which lead to disk load of 30oz/sqft, and 34oz/sqft.

while hexa was more stable, it still was not as stable as the quad with 8".

so, to prove this test out, I added weight to quad and brought it upto 1.85kg, which brought the diskload to 37oz/sqft and now it was almost as stable as before. . I've brought the f550 to 2.9kg and also repeated the test. and it was same . (about 40oz /sqft) very stable.

so, at least in windy condition, naza really...Continue Reading
Posted by askman | Apr 17, 2012 @ 02:04 PM | 13,000 Views
well, panasonic GF3 is getting a workout on my f550 with naza. It is a great camera and great value. with firmware hack, the video mode is as good as anything available. its four third size sensor only 22% smaller than nex-5n sensor, and used in many dslr.

anyway, I was testing my F550 with roll stabilization and tilt connected to the naza reg (roll servo had its own reg) and I got hit by glitches.

this basically reaffirm that you should never power the servo off regs that your multicopter depends on. lol. I did manage to land, but I was very nervous and I made record controlled descent. 8" props at 2.6kgm hexa load is still usable, but near the limit. I am waiting on the 9x45 from gemfans.

anyhow, here is the video.

GF3 test 4. tilt connected to RX. but powered by naza big mistake (1 min 38 sec)

update on 4/25/12
well: I finally tracked down this issue, and it was motor to esc connection. I swapped the esc out, and it is no longer an issue. I've tested that esc on ground, and it still works, so I am assuming connector issue.
Posted by askman | Apr 16, 2012 @ 09:39 AM | 12,847 Views
I finally got my gopro with sunex working well and fully focused. that was total pain to do. I finally used a street sign down the road to focus it in. just lot of iteration in 1080 mode to get it looking good in video . once that was done, 720 mode also looked good. I am using DJI 450 quad with 8" blade and naza. about as small as you can go and get great results in video

here is 1080 mode video
gopro 1080p.wmv (2 min 59 sec)

and here is 720 mode. testing fast panning (was 60fps down encoded to 30fps in sony vegas. no stabilization though still)

gopro 720r3 mode test using dji450 (3 min 55 sec)
...Continue Reading
Posted by askman | Apr 15, 2012 @ 09:29 AM | 13,374 Views
I've been doing lot of research into flight behavior and props on multicopter. Some just affirmed the old ideas and found some new ones.

This whole enterprise started with report of DJI 10" props breaking in air and trying to find alternative. Graupners are the best by all account and would have gotten the set, except for their current lack of availability precluded that for myself. So, I started testing props

The anecdotal evidence has always been to use light weight props, and this has always been old standby APC SF and EPP props. I've also had some hobby king 10x6 set on hand (they are very affordable) and purchased a set of 9x4.5 APC EP props. (figuring that they are similiar to graupner e props)

after testing, I find that APC EP props are not suitable for multicopter. they do work, but I could not get rid of wobble due to their weight. wobble was not big, but it existed in all condition and could not be tuned out. may be they would work better with slightly bigger motor, but not with stock DJI 920kv motor. also, I could not get 9x5 GWS 3bladed props to work well with naza. bit of wobble. could be due to balance issue as I could see at least 1 prop badly out of balance. (but again, 10x6 had at least as bad a balance on 1 prop and flew well) it is interesting, as gary had good luck with GWS and heavy loading. the motors do stay cool with gws 9x5. gary did have trouble getting rid of all vibration with gws, so not great...Continue Reading
Posted by askman | Apr 11, 2012 @ 05:41 PM | 11,367 Views
well, I am finally happy with the new Slow Stick LG. bit heavier than my original ones from 6 years ago, but lot stiffer. The new gopro adapter and new 4.4" gimbal is designed to be able to mount KK (openaero firmware) or openCC board.

the budget 4.4 gimbal is designed to use micro servo using pushrod to give tilt only control at affordable package with the LG.

it will be available in my website.
Posted by askman | Mar 27, 2012 @ 10:48 AM | 10,697 Views
Sorry for lack of updates:

We've been busy with servo issues for last couple weeks, and that has delayed our product launches. I am almost done with the new Airplane/Slow Stick setup and should have sample pic this week. new heli LG system is almost ready for testing as well. (I am trying to make a sample this week as well) lot of work going on as we push for product release of multicopter gimbals. Should update my website this week as well with some products being offered.

For airplane, we are testing KK board to stabilize the plane instead of stabilizing the gimbal. I believe this may be a good option for many. KK board combined with happysunday's openaero firmware looks to work really well. I will be using nano version of the code with older HK-kk board and full version with my blackboard. I will also test openCC board with gimbal control later on as well using tilt only stabilization and dual stabilization using 2 axis belt driven airplane gimbals.

Heli LG system will use proven multicopter gimbals. it will be offered with nex5 sized gimbal for 50 sized and DSLR gimbal for 90sized. tilt only will have adjustable roll angle to give you lvl video while hovering. 50sized should be available in 2-3 weeks while 90size is still 1 month out. with gimbals already being tested, just the LG unit needs to be tested for strength and manufacturability.
Posted by askman | Feb 28, 2012 @ 11:43 PM | 10,333 Views
well, I finally setup a new website. mostly information only at the moment, but will be adding to it. check it out and let me know what you think.
Posted by askman | Feb 17, 2012 @ 11:24 AM | 10,118 Views
Current Product roadmap 2-17-2012

Gopro vibration isolation mounting system. (samples going out monday to tester)

F450 quad system: (nose mount)
Gopro 2 Axis gimbal
Gopro Tilt Only Gimbal (upgradeable with roll)

F550 Modular system:

F550LG system
GoPro Tilt only vertical gimbal
GoPro 2Axis gimbal (complete with roll)
GoPro 2axis Yoke with roll shaft /front plate
nex5 Tilt only vertical gimbal
nex5 2 axis gimbal (complete with roll)
DSLR TIlt only vertical gimbal (design complete, available soon for testing)
GoPro 2axis Yoke with roll shaft/front plate
Pan Module for the LG system (design complete, sample going to tester)
Roll module upgrade for the Vertial tilt only gimbal.
various part kits for LG and gimbals.

Version of gimbals for mounting to AGLhobby Frameset/floating mount. (available soon)

Polecam module/adapter for all the gimbals. (including tilt only and roll/tilt gimbal) (design complete)

coming soon:
DSLR 2/3 axis system. (being designed)
Posted by askman | Feb 11, 2012 @ 11:08 PM | 9,562 Views
as promised, I will release some of my old gcode file used to create some of my old camera mount. I am starting with the old APCAM seris for slow stick. It is released under GNU GPL for personal use only. not for commercial sale. I am also making available the SS LG file.

I will update this thread as time permits. I code most of mine straight into gcode instead of using DXF. so, check back regularly for complete set.

next is trex 450 LG setup (v1.2) which uses the apcam gimbal.

I used old eco 8 ball and ball link on the apcam gimbal, but just about any ball link can be used. I also used 1" diameter delrin with 1/2" hole to make the ball link joint.
Posted by askman | Feb 01, 2012 @ 10:17 PM | 9,654 Views
as I have announced, I am back in business, but I will not be selling directly. My good friends at tppacks and dji-usa will be handling all my products for now. This is so that I can concentrate on developing my product line and produce best camera gimbal at affordable prices.

I have many ideas I want to working on, and as they become close to final product, I will have some beta testing opportunties for some people on new products. I will announce such opportunities here.

First items will be available for sale by 10th of Feb. These will include:

Gopro Gimbal in either Nose mount configuration or for DJI550 LG system.

DJI 550 LG system base kit.

latest video from seismicwave on HFP

20120202 askman "Crab" and gimbal test NEX 5N HFP (2 min 33 sec)

he is also getting the latest LG system and parts to update his gimbals. he should have it by saturday. I also expect Gary to have his DJI-550 running. I will also be shipping couple test unit early next week as well.

I am trying to get enough testing on various platform before release, so we can have successful launch. If all go according to plan, nex5 gimbal should be available by second half of the month. I will also have Polecam adapter and Pan adapter should be available by this time..

My next project is the DSLR version of the gimbal which will have a deeper and wider yoke I believe this will require slightly heavier duty LG and roll assembly. I will need to test it thoroughly before I will be confident. target is 3lb camera load. (most DSLR with reasonable lens)

the 550 LG system can easily be adapted to other multicopters

Nex5 system is in final testing, and will be available. (this month) It is very simple to change from gopro to nex5 so if you prefer, you can also get it with both yoke.

anyway, glad to be back.
Posted by askman | Jan 30, 2012 @ 11:17 AM | 9,104 Views
with help of seismic, I am learning lot about various FCB and its foibles. Gary has been having pretty good result from Naza at least flying f450 and my gopro gimbal. I also have gotten some hoverfly Pro footage from Seismic using my nex5 gimbal on my crab folder testbed. (thanks seismic)

20120129 askman crab HFPro NEX 5N (2 min 14 sec)

there are few things we need to do on servo setup that should improve things, but not bad for early test. we've been having some issues with openCC board with the gimbal control, so I will be looking at this issue this week. Seems like the state of gimbal control is bit of gamble. on the open sourced firmware, we will be giving feedback to the coders to see if they can make firmware fixes. I do believe as a community, we need to do our best to help out, but it also tells me that we need an affordable camera control board that we can setup specifically just for camera.

I will post more videos as I get more. Gary has been busy getting F450 setup perfected, and his latest videos are very encouraging. so pretty happy with how the gimbal is performing. I am making some minor changes for easier manufacturing and reliability, but overal, it is all set to go.

here is latest f450 video. Gary is running 5v on his servo, and going to try 7.4v next.

F450 GoPro Gimbal Test-08.mp4 (4 min 41 sec)
...Continue Reading