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Hangar 9 B25
Nice twin bomber project
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That is looking sweet Peter ! When you say you can do it - what do you mean - have you successfully operated both esc via the DPM or what ?
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I know it will work- or it will be sent back as 'not fit for purpose'  I am legendary in dealing with suppliers of 'experimental ' products for end users. That is to say when it has not been properly tested in most normal environments. In the last few years I have sent back all manner of stuff and threatened 'adverse publicity' on the supliers. It usually guarantees the desired result.  I don't think this will be the case here.

Soooo  It will work. This Sunday I hope to set up the test rig. One of the reasons is to check against items that might be genuinely faulty. Also to check the 'cut off action' is as anticipated.

The 'Day Job' is getting in the way at the moment.!

I just checked with HC. The stuff I ordered is marked as 'reserved'. I checked their status last evening, and it said they were back off New year holls. Also the website accepted my EMS option for delivery, which it wouldn't do before, so my order should be here by this time next week.

Next job to do is glue the ailerons & flap hinges. I just ordered som retract pipe and an air tank and  filler valve etc  from Phil at Fighter Aces. He has a extra large retract tank which provides a better retract action.

Why? well its one thing to have a high pressure in your tank. But if you dont have enough cubic litres of air, you get a pressure drop in the system, when the valve operates. This can lead to poor performance. People who paint spray for a living know all about this!   

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The retract tank has now been installed, along with the /pipework' for the nose leg. I will cut and fit the T- pieces for the mains later. I connected it all up through the solenoid retract valve.  I have acquired a new (but obsolete stock) emergency car starter pack complete with mini air compressor for a Tenner of a business client.  It has a 17AH sealed Lead Acid, so should be good for a bit of Lipo field charging this summer.

I had to make a few mods to the air tank location as you can see

/members/images/6947/Gallery/DSCF1759.JPG


The tank sticks out a bit as you can see. I have added a small lite-ply former to keep it snug. The retract solenoid valve is just in front of it.

I fired up the mini compressor only to find after several minutes of puzzled fault- finding, that the inflator hose had rotted away where it connected to the compressor. I re-did the end with a mini jubilee clip and tried again. This time we had PSI   I ran it up to about 80 and flicked the retract switch on the Transmitter. The nose leg vanished into the fus with a bang. Wow that was good, flicked the switch again, and out she popped.

Dead good! 

i left about 60 psi in the system overnight. The next morning I was still able to get another cycle or two, so those parts from Phil  are quality  stuff.

 As you may have noticed its been a little cold lately. Something went wrong with a valve on my central heating, so I had to fetch the oil filled rediators from the 'Playroom'. So I haven't been doing too much in there.

I had some good news from our little pals in Hong Kong. My Outrunners ,servos, and another BX5 charger are on their way by EMS . Hopefully they will be here very soon. 

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Looking good Peter. I have just ordered another motor from UH ( along with some other goodies ) for the Camel. have decided to go for a lower KV as I want to swing a 16 " prop -so spotted the 400KV version of the one I have already - £21 ....how do they do it huh ? terrific.
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Did you know they are opening a branch in Belgium in the third quarter of 2008
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Parcel Force called today!!

/members/images/6947/Gallery/DSCF1760.JPG



Thats 7 days (5 + Weekend) . Exactly as advertised. The tracking system was also spot on. I mentioned to my old dad that it might be here today, and I was not dissappointed.

I think its important to wax lyrical when the job is done right.  Nothing else to pay (Know what I mean)

The Turnigy motor is every bit as beautiful in the 'flesh'

/members/images/6947/Gallery/DSCF1761.JPG


This is roughly equivalent to 10cc glow. I shall do some bench/ power tests this weekend. And all for 22 measly quid. Its enough to make you want to buy the wharehouse!

And, of course they will fit in the B25 cowls with no surplus bits sticking out 

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Yes they are nice motors...and the price- well what can you say! I am equally impressed with the turnigy ESCs - I have several now, and the last one was a 60Amp, with switched mode 3 A BEC...again stupid price! It throttles and behaves as good as ANY I have owned...and that includes the premium brands Jeti and Hacker.It is also a lot simpler to set up than many I have used ! I have the 400kv version ( as yours ) coming soon...my account shows goods dispatched - yippee ! I will be using mine in the hangar 9 Camel with 4s and a 16 x 8 prop. I dont need loads of power ( around 75 WPP ) but do want a large prop for the large cowl, and slow sclae like RPM, hence the move from 600KV to 400KV...if I had just put the big 16" prop on the 600KV my amps rpm and watts would be too high

However...I will soon find something to use thre other 600Kv motor on.... even it's just "workmate jewellery"!!

Edited: 21/02/08 23:11
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Incidentally, my 400KV 50 series motor is designated 50-55A

see here

Yours however according to your picture ( bit out of focus) is 5065-400.

I cant find that model on the site anywhere..... wonder whats going on there then ??

Edited: 21/02/08 23:21
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Thats arab camera work (camera sheik)

here's the link: 

http://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=4914

I had delayed buying the two esc's till I had a chance to test the motor (on one I aleady have)

I was just thinking of ordering 2 Turnigy 80A units.In view of your comments, I shall order them tomorrow 

Only driven 220 miles today + half a bottle of Pinot Grigio...................................zzzzzzzzzzzz 

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Ah... cheers...looks like they are listed under hexronic rather than turnigy for some strange reason.

YOurs has a slightly higher amperage rating than mine. 

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Well now, I just ran the thing on a 6s pack with a 14 X 7 APC.

Wow!  got 700Watts  at 33 amps. Can't tell the RPM yet as the tach doesnt work under artificial lighting, but it was pretty draughty, I can tell you.

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Here is the port nacelle, complete with engine (motor?!) and retract. The supplied aluminium spacer mounts required cutting down. I thought they were threaded all the way through, but they were'nt, so I had to take a bit off each end. Ever tried cutting down spacers without a lathe?. Its a bitch I can tell you. Then I had to shorten the HT bolts by cutting them with a Dremel disk cutter.

Four hours later it was done. I stuck the dummy engine in with PU glue. The prop shaft on most electric motors is shorter than glow. I had to take out quite a bit of plastic as the motor frame was hitting the rear of the dummy cylinders. I ended up blacking out the frame with a large indelible felt tip pen to hide all that lovely bronze anodising 


/members/images/6947/Gallery/DSCF1763.JPG


Note! No 'bits' sticking out


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ENGINE TEST!

http://www.modelflying.co.uk/members/images/6947/Gallery/DSCF1764.JPG


Thought I might as well use the nacelle, as the motor was already mounted on it. The graupner discharge protection module can be seen hanging between the charge plugs. Two 5000ma batts are in the wheel well (so what do you put in yours? )

The unit was then run at @ 500watts/ 22A discharge. The ESC used for the test is a Castle Creations Phoenix 60A. It was programmed on my laptop to cut off at 6V. Of course, without the DPM that would have been Lipo Suicide. There is no point in flying a twin where one ESC could concievably cut a motor before the other.

After about 14 minutes the power curve was starting to droop a little. I moved the throttle up one click to keep it at 500watts.  The battery voltage indicated by the power meter was now down to 18V!

Thats 3 V per cell! (on load)

 Another few seconds and it was going to be all over- one way or the other.! At 17V indicated on the wattmeter, the green LED on the DPM changed to red (although not much use at 4004t!) and about 10 secs later the throttle blipped as a warning . If I had continued It would have blipped again, and closed the power down.

I decided to end the test and examine the batteries. I put them on the chargers and checked all the cells. None was below 3.2V and all are charging up as they should.

So the conclusion is that the graupner Discharge Protection Module does what it says. This is a good set-up for electric twins. This installation with the two Turnigy motors should give a decent 5 - 7 minute flight time on 6s 5000ma Lipo.

A simple Y lead to the two ESC's will connect via the DPM to the RX and ensure that both motors stop together. QED!

http://www.modelflying.co.uk/members/images/6947/Gallery/DSCF1765.JPG

Bit too close on my camera! nearing the end of the test .475W at 21A .Voltage is @22V on load 
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Ah... but as yet, you have not then tried it with both motors and twin ESCs?

The fact that the pack dipped to below 18V is of no problem as this was whilst the pack was under quite a heavy load, I routinely drop to around 2.75V per cell in these condituions which on your 6s pack is 16.5V 

The magic 3V minimum is really only for unloaded / lightly loaded cells so you have nothing to worry about IMO.

Good stuff...I eagerly await the twin setup static tests....no reason of course that they shouldnt be fine.....just keen to see the actual versus the theory

Thanks for keeping us up to date on things...this should turn out a sweet model

Edited: 24/02/08 12:33
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It could as easily be a 'Spruce Goose' model. The fact is its the DPM that is controlling things via the throttle, not the ESC.  I was out of Y leads!

you are quite right on the cell loading. I suppose I'm a bit jumpy, as I had a pack puff once (my fault I guess!)   

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Throttle Woes!

I've been fiddling about with the DPM (again) this week and summink aint right

There have been occasions when the Castle creations 60amp controller was'nt recieving a throttle signal via the DPM.  The units have to connected up in the correct order to enable throttle control to function. I thought it was just me.

Now I have recieved the Turnigy Plush 80 ESC's from  HC (Or HK!) I have been testing them out with the motors. Everything is absolutely fine there.

Trying the DPM again with the New controllers is a 'no show'  Just no way, no how would anything work. In desperation I put a servo on the DPM. THAT would'nt work either.

I needed an oscilloscope to see what was going on.  A blog on Watt Flyer showed a link to a free software program that is just what I needed. I can feed the servo signal from my Futaba reviever in through the sound card in my PC. As this provides two channels, and using a Y lead, I can display the Reciever signal against the signal AFTER the DPM. They should be about the same.

They're NOT. Not even close.

/members/images/6947/Gallery/throttle_sigs.JPG


The red trace is the reciever pulse at mid throttle. Exactly as it should be!

 The green trace output from the DPM  is just two 'weedy' little 'pips'  (hardly discernable) So its a dud.

I shal be sending it back to Gliders along with a print as above. I really would like to get this stuff working properly

I notice that some of the ESC,s from Turnigy are now being fitted with 'Balance Plug' cell monitoring facility.

You see I am not the only one who thinks along these lines.  

 

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Hi Peter,

I am learning a lot from your blog.

It is easy to see why a lot of folks steer clear  of EP,tis a lot of techi info to master for a layman like myself..

I get the impression  that a lot of  motors, esc ,chargers etc are not up to the job, it is a electronic minefield out there. Thank goodness we have people like yourself and Timbo to guide us lesser mortals.

Looking forward to the first flight of your B-25.

Kelvin.

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Hmmm, makes me feel somewhat justified in insisting that we see the results from the DPM when connected to twin ESCs!

That was NOT meant to sound smug....but does reinforce the importance of checking everything thoroughly in a practical and actual test...I too thought that the fact all was OK one 1 should mean it would all be OK on twins...but there ya go !

Please keep posting on progress Peter !!

I was aware of some ESCs being fitted with cell monitoring, and indeed of other stand alone units in a simialr vein...however the ability to monitor two seperate batteries AND deliver a completely linear and balanced signal to 2 x ESCs is the holy grail we are after.

Edited: 02/03/08 20:21

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