The round tubes look nicer. The square tubes are easier for DIY, but will probably weigh quite a bit more although I am unsure this really matters. Only time will tell.
I do hope to finally get time to add the gyros into the code over the coming w/e.
Ken back in post #145 you said you were making up only so many kits for the forum members. I would like to preorder your kit #3 from post #271. I have a trm/rcvr just need to get a battery. Is your kit comming with a connector for the battery side or do I need to order a battery with a particular connector?
Thought I'd better bring you current on where we are from a cost standpoint.Back in post #271 in this thread I discussed possible prices and packages. Since this is a totally open product, drawings and all, we should also be open about the costs. Everybody who buys an ELEV-8 should feel they're getting a fair deal, right? This is what I mentioned in post #271:
Airframe with mounting hardware (target price of around $100)
Airframe with mounting hardware, with motors, ESCs, props, wires, connectors (target price around $325)
Airframe with mounting hardware, with motors, ESCs, props, wires, connectors and Hoverfly SPORT (target price around $550)
I think #1 can happen without any difficulty. What I'm showing below in the graphic really describes #2 above, okay? We targeted $325 and you'll see from the draft bill of materials below I think our costs are somewhere around $166. This is what's not included in the $166 internal cost estimate shown below:
Inbound shipping from China for HobbyKing parts; inbound shipping on all other pieces from other suppliers. Add 25% cost to all HobbyKing parts for shipping.
Stocking, kitting, and parts procurement from Parallax staff. We pay California wages.
Parts that are sent out to/from anodizing.
Cost of lead times and cash expenditure for inventory that doesn't generate return instantly.
Purchasing manager didn't have a chance to shop the Acetal Delrin yet, and it's expensive. That might go down.
Heatshrink. Not sure of the best source to procure that. Got a tip?
Issuing/receiving of internal work orders to transform raw material to finished goods. An administrative cost - not too consuming.
Non-recurring engineering costs. Design, documentation, assembly costs to prepare pictures, video, etc. This is being done on free time from myself, Nick and Kevin since we couldn't justify it easily internally. You'll see that from the timestamp on our posts.
I imagine our complete costs (all burdened labor, materials, shipping) to assemble #2 are probably about $275 or so after including the above considerations. I think the $325 mark is entirely reasonable for #2 and that #3 could be offered for about what we guessed at $550. ELEV-8 just might pay for itself if enough are sold over the long term. Distributors won't be able to buy the kit because they would simply make it more expensive for you (ie, factory-direct sale only). And it can't have an opportunity cost once we get into manufacturing, meaning it must not occupy our staff when they could be doing more productive projects (and that we might run these parts in the evening). I want to be open with the numbers so customers understand how the price is calculated for ELEV-8 (and to provide some internal justification for being involved in this project). Also, somebody else might want to take over the project at some point.
Ken back in post #145 you said you were making up only so many kits for the forum members. I would like to preorder your kit #3 from post #271. I have a trm/rcvr just need to get a battery. Is your kit comming with a connector for the battery side or do I need to order a battery with a particular connector?
Gotcha, Dave. Consider it done.
The battery will use the EC-3 connector (not a dean, as they are too expensive).
Just so there's no confusion, we'll start this with the SPORT board and switch to the OPEN when it is available. If you buy a SPORT and then want the OPEN we'll figure out some kind of discount so you're not paying full price twice. The OPEN is in prototype stages now. The prototype area is for an accelerometer or GPS. Should be fun, right?
Perhaps you should state the battery is not included, as it is often purchased at the same time as motors, escs, etc.
I am trying the velcro style straps from HobbyKing to fasten the battery.
I have noticed the "O" rings for the propsavers are snapping while just holding the propellors on (without use). I am a bit concerned about these in flight so I might see if I can buy some better quality Orings locally.
I have ordered larger 11x4.7 props as well as 3blade 8x4 (normal and counter-rotating). Hopefully I will get either Sat or Sun to try the gyro code.
That looks very nice. I'll pay more - $1000 or more for a 'flying for RC dummies' package. Or more specifically, "flying for people who are happy coding GPS waypoints into software but are not capable of gently landing a helicopter in a light breeze."
(My RC helicopter remains stuck in the top of a tree!)
I presume you need a GPS to be able to do this? Set a 'home' point. Fly to waypoints that have been preprogrammed. Hover in windy conditions. And something not demonstrated in that video but which ought to be possible - return to the home point and then slowly descend if the batteries are running down.
I don't know how that would work out in the field - I guess a laptop and a USB cable and some simple software to code the waypoints?
Thanks Ken. I've looked but didn't find the voltage? I found this battery which is an 11.1V. Maybe the voltage was discussed back in Clusso99's original thread?
I am pretty sure Kens motors are 11.1V. You would be better off with a higher 35C. Not sure how heavy 4000mAhr is compared to Kens. I have a pair of 1800mAhr IIRC which is really too low unless I use both.
I found that the prices were not much different for the higher 35C batteries. The 35C refers to the usage current. Remember we have 4 motors all chewing up significant current. Even higher values are possible but they tend to cost more.
I did find a calculator somewhere recently (try google) where you could put in your battery, motors and propellers and it would calculate the flight time.
While we wait for parts from HobbyKing to build our first 25 sets of ELEV-8 kits we have been preparing some SolidWorks drawings for you. These will be for any purpose you desire. We will provide DXFs, SolidWorks and any other native export we can easily produce. In the true spirit of open-source, you can do whatever you want with the drawings. You can even build your own quadcopter and sell them.
I concur - I've worked on this project nearly exclusive of my office time since it's a hard one to justify from a business perspective. Of course, my time is exactly that - my time! But if the office crew had it their way I'd be out selling products instead of flying quadcopters around.
Is the 25 kits the number of complete kits with motors, or the total number of kits? In other words, is there going to be more than 25 kits with just the frame?
Hey Cody - 25 kits will be complete with motors, frames, ESCs, etc (everything except radio and battery). I consider the initial manufacturing run to be an expanded alpha test. Anybody who buys them will get special consideration for future upgrades and changes. You won't see these on the home page of Parallax - they're for our forum members, at least until we get to the second run.
Just a little warning (again). The O-rings from HobbyKing (used to hold on the propellors) seem to have an extremely short life. They snap after a short time (2-3 weeks) without even being flown. Therefore, I am concerned they will not hold up in flight.
I used 3.5 mm bullet connectors for my quad 2217 turnigy motors.
But after 2 quad crashes I had doubts about these connectors and used more strong 4mm connecors (photo).
It seems better.
Have you heard of such problems ?
Jean Paul
Hey Jean Paul - I received your PM and yes, we'll be sure to get a kit for you. No need to worry!
The bullet connectors have huge potential for problems. And yes, we've had failures because of them. The failures fall into these categories:
- bad solder joints, where the connector was not kept hot enough during assembly
- mismatched brands that don't fit well together (sometimes too loose - keep it all a single brand). It's not that the Turnigy brand is bad (I think they're fine) but they may be bad if mixed with other brands.
- improper heat-shrink allows exposed metal, causing a short within the 5/8" OD aluminum tubes
Now we are soldering wires directly to the motor's wires, which eliminates (12) M/F 3.5 mm bullet connectors in the whole system. Connectors are a point of failure - they are worth getting perfect, every time if you must have them.
The other certainty we have is to use Loctite on all screws. Without Loctite, it's only a matter of time before your ELEV-8 crashes to the ground.
Just a little warning (again). The O-rings from HobbyKing (used to hold on the propellors) seem to have an extremely short life. They snap after a short time (2-3 weeks) without even being flown. Therefore, I am concerned they will not hold up in flight.
Hey Cluso99, we don't use those propeller saver O-rings. The force exerted on the propellers guarantees failure of the o-rings. Instead we are screwing the nut and washer down on the propeller.
How large are the bullet connectors? Any thoughts about replacing them with Anderson Powerpoles (http://www.powerwerx.com/anderson-powerpoles/powerpole-sets/)? If not in the kit itself, I would consider replacing the bullet connectors with these in mine (if I can be in the 25 ). I use these a lot in robots, etc. that don't require small connectors.
@schill, indeed those would be the ideal solution for quality and reliability. We will provide bullet connectors and leave the upgrades up to the customer. Starts to get into the realm of personal preferences, especially for engineers.
I used 3.5 mm bullet connectors for my quad 2217 turnigy motors.
But after 2 quad crashes I had doubts about these connectors and used more strong 4mm connecors (photo).
It seems better.
Have you heard of such problems ?
Jean Paul
I too have used the 3.5mm bullet connectors on a lot of RC planes without any issues. As Ken stated, you need to get this connection right. When I solder the connectors to the wires, I use water soluble flux and a good amount of heat. The flux helps the solder to flow better and seems to help it to bond to the casing of the connector as well. After you're done, clean the connectors with water, dry them thoroughly, and then put on the heat shrink.
I hope this helps...
Jim...
Comments
I do agree that the round tubes look nicer, and it is a better shape for something that moves through the air.
I do hope to finally get time to add the gyros into the code over the coming w/e.
Thought I'd better bring you current on where we are from a cost standpoint.Back in post #271 in this thread I discussed possible prices and packages. Since this is a totally open product, drawings and all, we should also be open about the costs. Everybody who buys an ELEV-8 should feel they're getting a fair deal, right? This is what I mentioned in post #271:
- Airframe with mounting hardware (target price of around $100)
- Airframe with mounting hardware, with motors, ESCs, props, wires, connectors (target price around $325)
- Airframe with mounting hardware, with motors, ESCs, props, wires, connectors and Hoverfly SPORT (target price around $550)
I think #1 can happen without any difficulty. What I'm showing below in the graphic really describes #2 above, okay? We targeted $325 and you'll see from the draft bill of materials below I think our costs are somewhere around $166. This is what's not included in the $166 internal cost estimate shown below:- Inbound shipping from China for HobbyKing parts; inbound shipping on all other pieces from other suppliers. Add 25% cost to all HobbyKing parts for shipping.
- Stocking, kitting, and parts procurement from Parallax staff. We pay California wages.
- Parts that are sent out to/from anodizing.
- Cost of lead times and cash expenditure for inventory that doesn't generate return instantly.
- Purchasing manager didn't have a chance to shop the Acetal Delrin yet, and it's expensive. That might go down.
- Heatshrink. Not sure of the best source to procure that. Got a tip?
- Issuing/receiving of internal work orders to transform raw material to finished goods. An administrative cost - not too consuming.
- Non-recurring engineering costs. Design, documentation, assembly costs to prepare pictures, video, etc. This is being done on free time from myself, Nick and Kevin since we couldn't justify it easily internally. You'll see that from the timestamp on our posts.
I imagine our complete costs (all burdened labor, materials, shipping) to assemble #2 are probably about $275 or so after including the above considerations. I think the $325 mark is entirely reasonable for #2 and that #3 could be offered for about what we guessed at $550. ELEV-8 just might pay for itself if enough are sold over the long term. Distributors won't be able to buy the kit because they would simply make it more expensive for you (ie, factory-direct sale only). And it can't have an opportunity cost once we get into manufacturing, meaning it must not occupy our staff when they could be doing more productive projects (and that we might run these parts in the evening). I want to be open with the numbers so customers understand how the price is calculated for ELEV-8 (and to provide some internal justification for being involved in this project). Also, somebody else might want to take over the project at some point.Attachment not found.Attachment not found.
Please share your feedback on any points or concerns. I don't want to be in a vacuum.
Thanks,
Ken Gracey
Gotcha, Dave. Consider it done.
The battery will use the EC-3 connector (not a dean, as they are too expensive).
Ken Gracey
Ken Gracey
Perhaps you should state the battery is not included, as it is often purchased at the same time as motors, escs, etc.
I am trying the velcro style straps from HobbyKing to fasten the battery.
I have noticed the "O" rings for the propsavers are snapping while just holding the propellors on (without use). I am a bit concerned about these in flight so I might see if I can buy some better quality Orings locally.
I have ordered larger 11x4.7 props as well as 3blade 8x4 (normal and counter-rotating). Hopefully I will get either Sat or Sun to try the gyro code.
(My RC helicopter remains stuck in the top of a tree!)
I found this nifty video http://multirotor-news.com/2011/07/10/best-position-hold-ever/
I presume you need a GPS to be able to do this? Set a 'home' point. Fly to waypoints that have been preprogrammed. Hover in windy conditions. And something not demonstrated in that video but which ought to be possible - return to the home point and then slowly descend if the batteries are running down.
I don't know how that would work out in the field - I guess a laptop and a USB cable and some simple software to code the waypoints?
I read that you are working on the documentation , pictures and videos. Its a key to get ELEV-8 flying nicely.
When do you hope to have a first draft ?
Jean Paul
I did find a calculator somewhere recently (try google) where you could put in your battery, motors and propellers and it would calculate the flight time.
My drone was spinning like a fool and I did not understand why.
I have put foam rubber between the central frame and the booms (as anti vibration)
Bad idea : the propellers were a bit tilted and not in the same plane.
Without this foam rubber it flys much better.
Jean Paul
While we wait for parts from HobbyKing to build our first 25 sets of ELEV-8 kits we have been preparing some SolidWorks drawings for you. These will be for any purpose you desire. We will provide DXFs, SolidWorks and any other native export we can easily produce. In the true spirit of open-source, you can do whatever you want with the drawings. You can even build your own quadcopter and sell them.
Ken Gracey
I concur - I've worked on this project nearly exclusive of my office time since it's a hard one to justify from a business perspective. Of course, my time is exactly that - my time! But if the office crew had it their way I'd be out selling products instead of flying quadcopters around.
{I like to think that anyway, then I can apply the corollary and picture my boss sharing the misery of my work life. }
I need to make sure Matt still has my shipping address so he can send me one of the first 25 for my future product predictions!
Ken Gracey
I used 3.5 mm bullet connectors for my quad 2217 turnigy motors.
But after 2 quad crashes I had doubts about these connectors and used more strong 4mm connecors (photo).
It seems better.
Have you heard of such problems ?
Jean Paul
Hey Jean Paul - I received your PM and yes, we'll be sure to get a kit for you. No need to worry!
The bullet connectors have huge potential for problems. And yes, we've had failures because of them. The failures fall into these categories:
- bad solder joints, where the connector was not kept hot enough during assembly
- mismatched brands that don't fit well together (sometimes too loose - keep it all a single brand). It's not that the Turnigy brand is bad (I think they're fine) but they may be bad if mixed with other brands.
- improper heat-shrink allows exposed metal, causing a short within the 5/8" OD aluminum tubes
Now we are soldering wires directly to the motor's wires, which eliminates (12) M/F 3.5 mm bullet connectors in the whole system. Connectors are a point of failure - they are worth getting perfect, every time if you must have them.
The other certainty we have is to use Loctite on all screws. Without Loctite, it's only a matter of time before your ELEV-8 crashes to the ground.
Ken Gracey
Hey Cluso99, we don't use those propeller saver O-rings. The force exerted on the propellers guarantees failure of the o-rings. Instead we are screwing the nut and washer down on the propeller.
Ken Gracey
I get mine here so there may be a variation between manufacturers. I'm not sure of the country of origin on mine.
For the 2-pole battery power connectors, I prefer the Dean, no problems with many hours, (and crashes).
My personal opinion, of course.
Schill and Publison: thanks for this info, indeed your connectors look stronger.
The 4mm Dualsky DB4 bullet I found are like that.
A bit expensive but a choice for relability.
Jean Paul
I too have used the 3.5mm bullet connectors on a lot of RC planes without any issues. As Ken stated, you need to get this connection right. When I solder the connectors to the wires, I use water soluble flux and a good amount of heat. The flux helps the solder to flow better and seems to help it to bond to the casing of the connector as well. After you're done, clean the connectors with water, dry them thoroughly, and then put on the heat shrink.
I hope this helps...
Jim...