Beam E4 Build Blog....

[rspblake]

Sometime there is an advantage in softer shafts, as you don't break 30 pound blades...

Also falling out the sky don't help, But I am sure that providing there not bending in flight, it's not a problem..

Also due to part replacement costs, as is this case one set of radix saved covers a complete crash...

Although I would of liked to have seen it bend less,

Been having a look though RR and its seems the normal thing is people expect to be changing shafts on a 450 as a standard every day thing on a crash.


.

[xygax]

That shaft looks like its made from align screw heads.... alll glued together.......5mm Silver steel an orignal pattern and a piece of cardboard, 2mm drill and a vice..... Take your pattern and cut a length of silver steel....Then place the orignal above the new piece in the vice using the cardboard to protect the work. Using the 2mm drill rotate the patern until the holes are true across the silversteel and line up the ends.... drill two holes.... you dont need a pillar drill and vee blocks.... You doo need a quality 2mm drill bit thats sharp... I made one for a twister and never made another one.... but you will smash bearings in a prang

Steve

[jiberjaber]

Rob - yep, I usualy expect to change the main shaft in a crash. Hence why I have a few align ones I think the key thing for me is trying to work out why it fell out of the sky. It was a repeat of the Trex crashes, so I suspect it is the electronics somewhere. I will contact Horizon on Tuesday to see of they will take a look at the RX and upgrade it to the quick connect software.

I have also ordered an Eagletree micrologger to take a close look at whats happening with the power supply etc.

Steve - Yes, thought did cross my mind about making a harder shaft, but as Rob has mentioned, for the sake of a couple of quid the Radix survived the crash, which is more imoptant to me

I managed to take the bearings out on this crash, both upper and lower main shaft ones, but it did fall from some way up!

[jiberjaber]

So I fainaly found a gap in the weather to go and have a fly at the field with this heli. The theory behind this is the long grass being there to catch the heli if it should decide to fall out the air again!

I have received the AR62000 back from Horizon, excellent service from them, they reported not being able to find a fault with the unit, but replaced it with a new one anyway for my peace of mind, which was great of them.

So all the kit was back in place and with my recently aquired eagletree logger I set off to put a few batteries through the heli.

Wind was about 20 MPH with 27MPH gusts according to my weather station, so it was interesting handling it in the wind.

The RPM is measured using a brushless motor RPM interface and the temperature is the heatsink on the ESC. Recording is set to start after the motor RPM has got over 3600RPM to remove the recording of the ESC start up song etc.

Pitch is set at +/- 13 degrees and cyclic at 6 degrees.

Running an 11t pinion, three 2100mAh revolution batteries later here are the results:

1st Battery
First flight was just less than a minute in IDLE1 at 75% (2900ish RPM) on the govener and then into IDLE2 which is 100% (3200ish RPM). I managed to blow out the tail in a tic toc at around 3.2 mins in to the flight.

Looking at the graph maybe the motor could have recovered the headspeed if there was less of a demand for current put on the ESC, I will have to investigate the gearing and ESC for that one I think.

Pack Start / End Voltage: 12.51 / 9.19 V
Max Current: 59.35A
Start/End Temperature: 21.2 / 37.2 Deg C
Total battery capacity used: 1916 mAh
Total battery capacity put back in by Cellpro4: 1890 mAh



2nd Battery
A large part of this flight was flips, loops and rolls and stall turns, mostly in IDLE 1 and then later on in IDLE2. Quite a lot of bogging just after teh switch to IDLE2 when I was trying some Aileron tic tocs. The lack of spikes in the current demand here make me think it may be more gearing related.

Pack Start / End Voltage: 12.52 / 9.30 V
Max Current: 54.63A
Start/End Temperature: 23.3 / 36.4 Deg C
Total battery capacity used: 1720 mAh
Total battery capacity put back in by Cellpro4: 1652 mAh



3rd Battery
The majority of this flight was in IDLE2 which is 100% (3200ish RPM). Within the first minute there were some large pitch pump climbs (something I havent been able to do in the garden because it runs out of space too quick!).

I went a bit wild on the flips and rolls here as the headspeed shows. Again, not as much demand on the current as the first flight, so will need to take a look at the gearing.

Pack Start / End Voltage: 12.54 / 9.65 V
Max Current: 47.62A
Start/End Temperature: 22.1 / 30.34 Deg C
Total battery capacity used: 1437 mAh
Total battery capacity put back in by Cellpro4: 1436 mAh




Summary:

Need to take a look at:

the tail (Set up / Chinese weights / new gyro?)
Gearing (currently 11t)

[jiberjaber]

I noticed on another forum that the pitch links are different on the on-line version of the manual to those in the paper version included in my kit.

In true commical biology style....

From the bottom up, the D links connect from the Servo Arm to the swash, the C links connect to the seesaw mixing arm and the B links connect to the Blade holder.........

The A link connects to the fly bar arm spacer. I found that to get the same length of these links I needed to put them on opposite ways on the fly bar arm spacer, i.e. one pushed on with the larger diameter to the right and the other side to the left.

Here's what mine are set at.

A LINKS: 29.13mm / 29.13mm
B LINKS: 25.44mm / 25.50mm
C LINKS: 45.60mm / 45.29mm
D LINKS: Pitch, 40.7mm; Aileron, 41.1mm; Elevator, 40.5mm
(pitch servo for me is the RHS when viewed from the front)

The variance in the B & C links is to account for blade tracking. The D links are a result from swash levelling (using my Trueblood tool), I think a bit of sub trim will fix the lengths if I could be bothered

I am a little worried about how little of the slide pins remain in the washout block at full negative pitch, but it seems be be enough of the 7mm of displacement in there to not be causing a problem. Ideally I would like the max pitch to coincide with the washout block just leaving a small gap at the top of the travel with the head block - this would give more metal in the washout at the bottom of the pitch range, I might have a lok at this at some point.

I also had to add a space to the anti-rotation bracket to allow more cyclic on the elevator, there was a little bit of binding on forward elevator of the servo arm end of the link.

My servo arm balls are at about 13mm out

[jiberjaber]

So - I forgot I had graphed some data from the -8 motor when I fitted it whilst up North. Here's the details in graph form. This is with a 13T pinion, but I forgot to record how much I actually put back in to the batteries on the charger. I have a 55A V2 Scorpion ESC on the way so will take a look at the performance once that is fitted as I think the 45A Jazz is limiting the performance of the motors.

Battery 1
Pack Start / End Voltage: 12.55 / 9.69 V
Max Current: 44.24A
Start/End Temperature: Not recorded
Total battery capacity used: 1505 mAh



Battery 2
Pack Start / End Voltage: 12.50 / 9.86 V
Max Current: 36.46A
Start/End Temperature: Not recorded
Total battery capacity used: 1864 mAh




I also managed to snap a skid leg today, after rebuilding the Beam last night (and also after a bottle of wine) I forgot to check the rotation of the tail blades.

It didnt look right when I spooled up and of course as I left the ground, it went in to piro hell. I was in idle up, so when I put it down - I managed to do so with -11 degrees of pitch and nearly full head speed!

These skid legs are realy tough given I think I have had 5 crashes so far and they have walked away from all of them but this little mistake!

Moral of the story - fix heli then drink wine! I went on to have two realy great flights with the beam tonight as it was still flyable

[Backrowslea]

Great thread, have been looking at this beast as an alternative to the 450, not sure if I should get a bigger nitro or upgrade my little elec.....

Not sure my heli knowledge would be up to the complexity of the beam... different teeth, current draws...... lol

I plug the batt in my esky and off we go!

[richieclarkie]

Great thread, have been looking at this beast as an alternative to the 450, not sure if I should get a bigger nitro or upgrade my little elec.....

Not sure my heli knowledge would be up to the complexity of the beam... different teeth, current draws...... lol

I plug the batt in my esky and off we go!

Don't worry about complexity of this thread. Jason has started this thread and lovingly contributing to it and is just a way of gathering detailed info.

Basically all you need to do is buy a beam, fit the Scorpion 2221-8 motor and 14T pinion. Set your TH curve to about 75 to start with and work your way up until it feels comfortable....... Thats it

Most of us never fit a logger to our heli anyway so don't let all this stuff put you off.

[jiberjaber]

Yeah - what Richie said basically. I fitted the logger because I had a specific problem of the heli falling out of the sky for no obvious reason. I think this is cured now by a replacement receiver, but I did think it could be voltage or static related at the time, hence the voltage logger.

[beerdeor]

Jason excellent write up very usefull having just built mine with the 8 motor in it what curves are you using more importantanly what curves would you recommend for a newb are the curves in the build manual good or is there better
keep up the good work

jim

ps im not a complete newb i can fly the beam but not great at it

[jiberjaber]

OK - had an excellent morning at the field today, I decided to fit the 14t Beam pinion that came with the kit to the -8 motor, most other threads on other forums recommend the 13t but I was getting lots of bogging and the tail was blowing out on me.

What can I say.... I was absolutly blown away with the performance. The only limiting thing I can see at the moment is the current draw from the battery.

Last time I was able to tic-toc like I do on phoenix was with my Raptor when I had first fitted the Kasama head and it was teh same flight I blew up the OS50 that was in it.. that was emense power just before it blew up... the Beam now feels like it has immence power as well... the difference is day and night!

The head speed difference off the eagletree log isn't all that much, maybe 200 RPM more I think (13t was about 3186RPM), it's tricky to guess what manouver is the same between a few weeks and some lines on a graph!.

Elevator and aileron tic tocs were a breeze with no blow out, which I had been suffering before. I am only running at 75% and 85% throttle curve governed in idle modes 1 & 2 respectivly.

Heres the graphs...

Battery 1
Pack Start / End Voltage: 12.54 / 9.27 V
Max Current: 44.24A
Start/End Temperature: 16.4 / 34.3
Total battery capacity used: 1641 mAh
Max Headspeed: 3381



Battery 2
Pack Start / End Voltage: 12.52 / 9.37 V
Max Current: 46.6A
Start/End Temperature: 19.4 / 36.9
Total battery capacity used: 1877 mAh
Max Headspeed: 3431

[jiberjaber]

Jason excellent write up very usefull having just built mine with the 8 motor in it what curves are you using more importantanly what curves would you recommend for a newb are the curves in the build manual good or is there better
keep up the good work

jim

ps im not a complete newb i can fly the beam but not great at it

Hi Jim,

I am running mine governed on a Jazz 45A ESC, I run 70% flat line with a little ramp up from 0 to 25% stick in normal, then in idle 1 and 2 they are flat line governed 75% and 85%. Never bothered with curves, just used the govener.

I am sure Richie could divulge his settings though

If you run the 13t that should be sedate enough for beginner flying, 14t is a bit mad, not tried 15t yet but I might at some point <evil grin>.

[jiberjaber]

So I think I now know the problem with my Beam and it bogging, I noticed the other day that Craig is using 25C lipo's. Back when I bought my three lipos from Mike at Aurorra, I didnt think I would need much more than 18C, so that is what I bought! I had forgot, but this explains the headspeed sapping that I am seeing in extreme pitch demands, lack of juice in the battery!

I am going to buy a 25C lipo to confirm, I think I will be a bit gutted not to have had the foresight to buy larger discharge batteries at the time!

[richieclarkie]

Well out of interest I'm using 18C revvos. So if you think that mine looks like it's got enough power then I doubt it's the c rating.

[jiberjaber]

Well out of interest I'm using 18C revvos. So if you think that mine looks like it's got enough power then I doubt it's the c rating.

Ah! - so i shall put off getting a 25C just yet then, I have a 55A scop turning up this week from Rob at evorc.com so will see if it is that then. There are only two things I think it can be now, either battery capacity or esc capacity. I have seen some wild 60A spikes through the Jazz with the -6, but I have only seen 45A so far through the Jazz since fitting the -8, I was wondering of the ESC was folding back the voltage when reaching a certain current, but I am not to sure.

I'll see what the ESC does first, as I think that is the only difference between mine and yours if you are also on 18C