[gbanger]

Now I'm worried, I've got an Ice Light 75 in my Hotliner, what speedie are you using in your Hotliner, Kieran?

[Skidz]

Here you go Jason - this a Castle Cremations customer survey link I received by email this morning.

http://www.magnetmail.net/forms/display_...uid=CASTLE&fid=35027&rtype=nonmm

Share the joy.

[secant0give]

Well the 100 A castle creations Icelite ESC seems to work just fine!!
It's a little heavier, this is mainly because of the extra heavy leads

A quick report on the first flight of the shoestring. It wants to make a sharp left turn on take off so only about 1/2 throttle is what's needed for the take off run and a heap of right rudder. My take off on the second flight was a little better but it still veered to the left. I'm going to up the rudder throw a bit to counter this.

It doesn't like having too much elevator used in a turn. You'll see in the video when I tried to make it do a pylon turn with full rates, it highspeed stalled and plumeted virtically towards the ground. Fortunatly I half expected this, was ready and had a little height. Never the less it was a bit of a scary moment !!

It flies reasonably fast, probably not quite as quick as a rarebear and on low rates and at speed it's very solid and grooves like it's on rails. I quite like the way it flies when it's going fast and in the air. It's nicer to fly than a rarebear in that respect. It's quite a slippery airframe and it carries it's way very well. It does not slow down easily and picks up speed as soon as you put the nose down. This makes it a bit chalanging to land on our short strip. That conbined with the fact that it's reasonably heavy and does not overly like being flown slowly. You'll see this in the video when I slow it up. She behaves up to a point then smartly lets you know your mistreating her by suddenly dropping a wing. If I didn't add power at this point I fear she might have spun. Probably would have if no power was added and elevator was held on.

A rarebear alomst seems to stop when you back the power off with the shoestring it seems to retain it energy noticably longer. It's a lot like the viper to fly.

Tho' landings require a couple of approaches at this stage I quite like the way it flies I'll probably try a lighter battery pack it running a 2600 at the moment I might try a 2200. There are a few adjustements to the rates and expo and It will be a lot better.

http://youtu.be/dyPUs8TdPs8

[wingtipper]

mate, eeeeeerrrrrmmm . im not sure i like that models charactoristics , it flew exactly the same as my HK focus i had , even looks similar with its short fuselarge and large wingspan, except the focus was a 40 buck plane and underpowered .

[Flying fisho]

Wow, & I am finding the Pulse a handful to land. Well handled Jason.

[secant0give]

mate, eeeeeerrrrrmmm . im not sure i like that models charactoristics , it flew exactly the same as my HK focus i had , even looks similar with its short fuselarge and large wingspan, except the focus was a 40 buck plane and underpowered .

Hmmmm it's not that bad a flier, you've got to understand that it's built for a purpose and that purpose is to go as fast as it can with that motor prop and battery combination, and fit the other rules of the EF1 class.

That high speed stall did look nasty and there wasn't much time to recover as it left the plane doing over 100ks traveling straight at the ground but there was a reason it did this. That reason was because I gave it full elevator in high rates, traveling at full speed, in hind site not an overly wize thing to do. I did it to see how tight it would turn and I half expected it to drop a wing and guess what, it did!! There was no way I'd recover from that if I wasn't half expecting it. I was actually suprised at how quick it happined when I looked back at the video. However it's not a fault with the plane if it had crashed it would have been pilot error that caused it 100% for sure.

These planes are a trade off, they have longish narrow wings so they can turn hard with the least drag. However this layout, while having that drag advantage, has the disadvantage of a rather sudden stall. You've got to remember that the plane weighs about twenty times more when it's turning hard like that and it's a big ask for those wings to produce enough lift to make it fly nicely around a very tight turn. Can they do it nicely? The answer is yes, but push it too far and look out, here comes the ground !!

The other nasty looking thing it did was was when I deliberatly slowed it up to see what it handeled like at low speed. I was allways going to slow it up untill it stalled, That's why I did it with some height to spare. I wanted to see what the stall was like and again, no great suprise one wing stalls before the other. You can see in the video, my reluctance to try and land her too slowly after that.

This is a plane with a bit of weight, the wing loading is around 21oz per sq foot. The air frame by it self is not overly heavy, actually the wings are suprisingly light. All the weight is in the motor and the 2600 4S lipo pack, which by the way, gives a duration of 4 mins with little to spare.

Here's the data from the ESC of the first flight and some of the second flight before it ran out of memory

   

[Skidz]

Nice graph. That ESC is getting extremely hot.

What do you think is causing the rpm and voltage to drop when you throttle up? Is this prop loading when you release the bird in to the sky?

Did you doppler the video to see if the RPM is correct?

[secant0give]

Nice graph. That ESC is getting extremely hot.

What do you think is causing the rpm and voltage to drop when you throttle up? Is this prop loading when you release the bird in to the sky?

Did you doppler the video to see if the RPM is correct?

Dave you allways ask good questions

Your right Dave it does look as if it's getting hot. I'm not sure where on the board the temp is measured, or even if it's being scaled to represent the hotest temp in a place near where it's measuring.
It does look like it's trying to monitor and feed back to the controller in the second flight between 900 and 975 seconds as the temp line is pretty flat, at it's max point, it's like it's plateued.

It promped me to send the following email to their support people:

G'day,
I purchased an Icelight 100 ESC to use in my shoestring after the Icelite 75 ESC I purchased burned.


I am using the standard EF1 set up in my Eflight shoestring 15, this is as follows:

2600 mah 4S Lipo pack
E flight power 25 1250KV motor
8X8 APC thin electric propeller
Icelite 100 ESC

I see from the temperature line on the Data logger chart that it is reaching nearly 100 deg C
This is quite a high temperature for electronic components to deal with. The ESC is only drawing just over 60A I've attached an image of the graph from the Data logger.

My questions are:

1) is this the normal expected running temperature?
2) Where abouts is this temperature measured from on the board? It it measured very close to the fets? if so is it the actual measured temperature or is it scaled to represent the Junction temperature of the fets?
3) what is the maximum temperature that it can run at continuously.
4) What is the maximum junction temperature of the Fets used in this controller (Tc)
5) looking at the graph of the second flight I can see the temperature seems to level out at around the 900 second mark. Is this some kind of temperature monitoring and feed back that the ESC is doing internally? The temp line looks unnaturally flat between 900 and 975 seconds.

Many thanks

Jason Vanajek

---

I guess you'd expect to see the prop unload in the air this is the case mostly, but with steep piched props, they can actually draw more current when they get moving. This one is an 8X8 so it's conciderd steeply pitched.

What you see in the graph while things are steady, ie the throttle is wide open, I think is the usual voltage and current dropping over time with the dischargeing of the battery pack. There might be some current limiting being done by the ESC because of the high temprature. This is not very apparent in the current (Amps) line but the temp line looks like it might be that way. The plateu we see in the temp line could also be what ever they are using to measure the temp maxing out, tho' I doubt that.

I would expect the current to rise steeply as the throttle is opened and as the current rises the voltage gets pulled down due to the internal resistance of the lipo's.

The RPM falls off slower than the current and the voltage during the times when things are steady ie the Throttle is wide open. I would expect this, as the "power required" to RPM ratio is not liniar. ie it takes much more than 10% greater power to obtain a 10% gain in RPM. So that part of the chart looks plausable.

I did a pitch speed calculation and it was about 170kph at peek I think this is roughly believable as it's probably doing about 135-145 kph in the air. I havn't done a dopler shift measurement but on the face of it I would think it will agree fairly well. I will do it none the less as soon as I get some better video and have the model nicely trimmed and dialed in. It's only had two flights thus far

[Skidz]

[Potential thread hijack - sorry. ESC info]

Well, you know me by now Jason. "Have I... got a link... for you" (using my best Tony Packard Holden advertisement voice).

I believe this information relates to your ESC temperatures as I don't think CC Ice series have AFW (Active Free-Wheeling). Also check out the other videos from this guy. He is a legend in the electric helicopter forums. There are videos by this guy (Tony) where he explains why some ESCs get hot and others don't (again, AFW) under same/similar loads.

To translate the contents of the video for the non-electronic folks, what this person is saying is that when an ESC is controlling the speed of a motor, it is switching voltage on and off very rapidly (thousands of times per second). Each time the power is switched off to the motor, a magnetic field collapses that generates power as it does so. This power is bled off as heat in the ESC (to get rid of it). The more current you are drawing and if you are at mid throttle, the most switching of this power will occur (and therefore a lot of heat).

With Active Free Wheeling, the current from the collapsing magnetic fields are turned back in to the motor with no heat being created in the ESC. The motor gets hot instead (but it is designed to handle it easy). The ESC stays quite cool if it has Active Free Wheeling. Unfortunately, AFW is not found in low cost ESCs.

---

Looking at your graph again I think you need to get some airflow over the heatsink. Temperature is usually measured on the heatsink (internal side). I think that would knock about 30 deg C off the temp. I also can see you flew on a stinking hot day as the heatsink was logging 35 deg C before you even throttled up. I believe with ventilation you will be flying with much cooler temps. I don't think CC will come back to you with any useful information other than the ESC is working fine (albeit "hot").



http://www.youtube.com/watch?v=uqzOQGiwGnE&list=UU7lc_DFDwD3wDHd-ixH1gfA&index=3

[secant0give]

Here's some graphs of the flight data from the last three flights on friday

The peak temprature has fallen quite conciderably

Now the question is why was it getting so hot on the previous Sunday? I think I've found the answer, The back plate of the spinner was very close to the cowl and while it ran nice and free on the bench I think the cowl might have expanded while sitting in the hot sun and was binding slightly. The Sunday when I first tested it was quite hot. I can see where there's a bit of a rub mark on the very front of the cowl as well, that could have been just loading it up enough to cause the trouble. On friday it was sitting in the shade and it also wasn't as hot a day as Sunday. I've shifted the collet out a bit on the shaft so it has more clearance and should cause no further problems. I've posted graphs from Fridays three flights. I'm much
happier with it now !! I will be setting the timer a bit shorter tho' , down for 3 mins to two so I don't flog the batteries so hard

   

[Skidz]

Hi Jason

Much cooler
Did you do anything else? Ventilation? The current log appears the same as last graph posted.

[secant0give]

Hi Jason

Much cooler
Did you do anything else? Ventilation? The current log appears the same as last graph posted.

Yes I noticed that too but I didn't do anyhting else, The ventilation is the same as it was for the earlier flights and done just how it's specified in the instructions. The ambient temp was a little lower on the day of the later flights but not that much.

Tho' the amout of amps being drawn by the whole system is one thing but the amount of power being disipated in the FETs is another as we see from the tests on the videos you linked to. There must be a reason that it got hotter in the earlier flights and there must be a reason that it didn't draw much more current as well.

[secant0give]

Here's the Box the shoestring now lives in.

I made this so it wouldn't get damaged while being transported in the trailer. It's much easier to store like this at home too.
I've made a couple of these boxes now, pretty easy as the foam can be ordered allready cut to size. All I had to do was bond them togethe using water based construction adheasive. Then I used HMG to hold the various blocks on the inside of it for the wings and fuse to rest on.
The box is very light and also keeps the plane from getting really hot if left in the car.

   

[smuzz]

Hmm - not bad at all. What would each box end up costing?

[secant0give]

the material for the shoestring's box probably cost about $25
But when I ordered the material there was enough foam for a bunch of stuff
on the invoice they just wrote missalanious foam cut to size so it wasn't itemised. There were also different grades of foam in the same order.

To give you and idea,
Here's what I got cut to size for $112 including the cost of delivery. The denser grade of foam is more expencive I think SL grade is either 12 or 16 Kg/Cu m

SL grade (small box)
2 of 38 X 420 X 300
2 of 38 X 1086 X 300
2 of 38 X 1086 X 496

SL grade (large Box)
2 of 38 X 580 X 538
2 of 38 X 1856 X 538
2 of 38 X 1856 X 656

for wing cores:

M grade 20Kg/Cu m
1 of 50 X 360 X 1600

24 Kg/Cu m
1of 50 X 360 X1600

28 Kg/Cu m
1 of 50 X 360 X 1600

32 Kg/Cu m
1 of 50 X 360 X 1600

[wingtipper]

Hmm - not bad at all. What would each box end up costing?

i would expect it to cost mates rates for friends and built to size