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Jun 10, 2012, 06:34 PM
Dale Kramer
KiloOne's Avatar
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Latest x-ray view of battery box and attachment scheme to wing spar.

Drawings are out for waterjet right now.

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Jun 11, 2012, 11:40 AM
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Neil Stainton's Avatar
Originally Posted by KiloOne
Here is a picture taken with a Flir IR camera of the BMS board balancing the cells while charging my RC pack at 5a.
Interesting photo. Isn't 175 deg F a bit high?

Jun 11, 2012, 04:14 PM
Registered User
That does seem high. What do you figure the typical balancing currents are on a battery that large?

Battery mounts look pretty slick.
Jun 11, 2012, 05:52 PM
Dale Kramer
KiloOne's Avatar
Thread OP
The 3W resistors at my 1.7W level are good to over 300degF.

I am more worried about radiant heat transfer to other things like PCB and battery case.

Case is vented and resistors have 1/4 inch of air between them and PCB with fire blanket over PCB under resistors. I think it will be OK. Testing will prove it or I will change it.

Jun 17, 2012, 04:59 AM
What goes up must come down..
Congrats Dale for your success and thank you for your kindness of sharing all these info's + experiences.
This thread is really interesting!
Jun 18, 2012, 03:22 PM
Dale Kramer
KiloOne's Avatar
Thread OP

Sorry about the almost non-existent audio but you can read the display to see it working. No time to redo video, had to do with Iphone by myself, mic was away from me I guess.

eLazair BMS test 2 (3 min 25 sec)

Jun 20, 2012, 03:43 PM
Registered User

lazair kit

please you can sale one kit for me , or plans ? . i want buid and fly one
Jun 21, 2012, 10:05 PM
Registered User
Dale: Thanks for sharing this process - it has been a good read and very interesting. Hope to see you in Oshkosh and would like to discuss getting involved somehow.We are working on an electrification project that could benefit from your BMS tech. - Maybe we could talk about licensing ... Turner
Jul 06, 2012, 09:31 PM
Dale Kramer
KiloOne's Avatar
Thread OP

We will certainly be posting here when the production schedule is determined.

Not considering making plans available at this point.

Jul 06, 2012, 09:34 PM
Dale Kramer
KiloOne's Avatar
Thread OP
Here is a picture of the first pack I have assembled, hope to add the high power wiring and test tomorrow.

The schedule is very tight to get everything done for Oshkosh but I am still trying.

Jul 20, 2012, 01:25 PM
Registered User
Originally Posted by Sean Sweeney
Wow! Dale,

I just stumbled across your thread. This will be fantastic! I don't know if you remember me, but I first met you when my father and I were up in Canada and he bought your Super Floater. We manufactured the HummingBird ultralight. My Dad and have been flying electric models since before we were flying ultralights and have always wanted to electrify one. In fact I recently purchased an early HummingBird with the old Partner engines, as this was the lightest model to convert some day. However the Lazair is a much more efficient aircraft and I am certain you will have no problems achieving your goal. I will subscribe to your thread and closely watch your progress, and I look forward to seeing you and the eLazair at Oshkosh!

Sean Sweeney
Sweenie --- Canada?
Would this be the same Sweeney from Guelph who ran a hang glider shop? Colin, wasn't it?
I was a customer there.
Alex Smith
Jul 24, 2012, 08:00 PM
Registered User
It looks like Dale has made it to Airventure. You can view the show on these links. He is in the air now. You can also see his Lazair sign near the fence along side the ultralight runway. Hope his new battery system tests out ok and looking forward to his report when it is all over.

links to webcams here

wish i was there.

Steve from downunder
Jul 31, 2012, 09:02 AM
Dale Kramer
KiloOne's Avatar
Thread OP
Oshkosh 2012 Update

Well, I can't remember an Oshkosh that I expended as much effort to attend.

In addition to the more than full time schedule this year, there were many through the night sessions.

When it became apparent before Oshkosh that I would not be able to have the eLazair ready in time, Conrad Huffstutler drove up from Texas with my Lazair trailer in tow to help out.

Conrad will be the young blood in this Lazair revival and so far has helped out a lot since we took the prototype eLazair to Texas last winter. He has provided the water jet parts for this year's power system and he designed and built this year's instrument panel.

So, with Conrad helping for the last week, we got things under control but then, after deciding to schedule one last eLazair flying day before we left, our trip to Oshkosh was delayed by vehicle transmission troubles.

We limped into Oshkosh late Monday afternoon in time to assemble before dark but we did not fly that evening.

On Tuesday, Wednesday and Thursday we were able to fly in 5 flying sessions. Between Conrad and I we put in about 3 hours flying time.

The performance was impressive, especially with Conrad's 165 lb body weight. It is my opinion that there were very few aircraft there that would stand a chance in a short takeoff and high climb angle contest with us.

Thursday evening we were doing a longer than normal system test and run-up to investigate an overheating bullet connector on one of the motor controllers when it caused that controller capacitors to puff smoke and the controller died.

By the time that controller was isolated and removed from the system, we were not able to fly that evening. Then, when we tied up that evening we noticed a cracked plastic wheel hub.

Spare wheel hubs were on our list to bring but after spending an hour looking for them before we left for Oshkosh, we left without them. With our 1 3/8 inch axle diameter, no spare wheels could be found at Oshkosh and we missed flying on Friday and Saturday.

Even so, we again flew more hours than any other electric aircraft at Oshkosh this year. We had a lot of interest and all in all it was a great show.

We still have no firm pricing for the power system or the new eLazair.

Due to our battery packaging arrangement to meet the 5 gallon ultralight limits, our plan is that the basic eLazair will be provided with 2.5 gallons of fuel (one pack per wing) which will give up to 45 minutes flying time. 5 gallons (two packs per wing) should give up to 90 minutes of flying.

I put on an eLazair forum Wednesday and on that morning I put together a few powerpoint slides. The slides can be found here:

So, back to the grind, I have to get a lot more flying hours and finish a lot of features before I can says 'lets make it'.

Jul 31, 2012, 11:01 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Dale, in slide #3, We have 40% more power in, what change(s) did you make to the Joby motor there?

diy motor tipsDrive Calculator
diy motor groupCumulus MFC

Vriendelijke groeten Ron
Last edited by Ron van Sommeren; Jul 31, 2012 at 11:35 AM.
Jul 31, 2012, 12:03 PM
Dale Kramer
KiloOne's Avatar
Thread OP

We impregnated the stator with thermally conductive epoxy.

We surface ground the outside of the stator and then reduced the gold heat sink housing ID to get an interference fit at room temp. Then we assembled the stator to the housing after heating the housing to 500 degF. This got rid of a heat barrier/bonding layer between the stator and the heat sink.

These changes allowed us to put more power through the motor without overheating.

To put this extra power through it we wound it as '6 phase', terminated in each 3 phase winding in Y and are using two CC HV160's per motor at 12s with good results.

Last edited by KiloOne; Jul 31, 2012 at 12:26 PM.

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