84 replies to this topic

[Wavess]

As many of here I decided to buy an Electro Telemaster, for basically 2 reasons.
1. I´ve read that the quality of the construction was great + comes prepared to electrify, so things become easier than a glow to electric conversion.
2. I liked a lot the posibility to install flaps on it, and motivated by the favorable change between $$ and €€, I decided to get it.

So here we go, I have my telemaster on his big box ready to work on it.

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[Wavess]

I don´t intend to make a built thread here, so I would just mention the modifications I understand could be interesting to others.

First step I started with the wing assembly.
Since I wanted to install flaps on it, I had to cut the precut flaps. This ends up with a little portion close to the fuse, that is also precut, so when you finish moving apart the flaps that region looks fragile, I fill the weak portion with epoxy.
After that with hinges installed, I made 4 fiber´s pcb small pieces, to fit my 4 mini servos, (telemaster comes with the room for standard servos)
I probably change stock´s plastic kwik links for metallic ones

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Edited by Wavess, 24 February 2008 - 04:40 AM.

[Wavess]

After that I didn´t like the rubberband method to hold the wing with the fuse. After reading some solutions over the forums, I decided to change it to the screw method, I think it´s safer and cleaner.
For this purpose I found on tower a nice wing mount set, this set make things much easier.

http://www3.towerhob...0001p?&I=LXE099

I had to build a 5 mm new center rib with a long tongue, to be inserted in the front side of the fuse.
I also cut 2 small plywood pieces in order to reinforce the wing´s upper side when the screw tights it downwards.

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Edited by Wavess, 24 February 2008 - 04:49 AM.

[Wavess]

Due to attachment restrictions I can only put about 2 pics on one post, so the fuse´s hollow to acommodate wing pic will come later.
I decided to move down the tails servos to maximize the interior space for fpv/uav or future equipment.
I needed to make a new mount for both servos, they are two hitec hs 81 minis, so the fitted ok on both fuse´s sides.

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[Wavess]

This mod gives me the whole space free for me and my gadgets,

The electric equipment I choose for it´s cheap stuff from china.

Motor:

http://www.hobbycity....idProduct=2099

ESC:

http://www.hobbycity....idProduct=2166

BATS:

http://www.hobbycity....idProduct=4129


http://www.hobbycity...?idProduct=4132

I´m thinking on buying one more of this one to have 6400 mah of capacity -

UBEC:

http://www.hobbycity....idProduct=4319

I´m not very confident on using this last component, probably I would change for a cleaner one. Suggestions admited

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[Wavess]

I didn´t trust on engine´s bullet stock connectors, so I decided to remove them and I soldered 3 4mm new ones to it.

The next step was to install the motor on the telemaster. Telemaster comes with 4 preinstalled blind nuts, that fits correctly for an axi 2820 mounting cross.
I did have that mounting but it´s impossible to adapt it to the chinese motor, I have to use the stock chinese mounting, so I needed to remove the blind nuts, and drill 4 new holes that came very close to the stock ones with bigger holes resulting from this operation. This isn´t a problem using enough epoxy to fill the unused holes.

The plane isn´t finished yet, so I´d keep posting the progress.

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[Mr.RC-Cam]

You're going to love this model.

Couple of personal comments for future builders:

Rubber Bands:
I was not excited about the stock rubber banded wing mount either. But, looking back, it has been an advantage for me. That is because I need to remove the wing to change the batteries. Plus, I am always finding a reason to get back inside the cabin to check on things. Popping off the rubber bands is quick and easy. However, I did replace the wood dowels with carbon fiber rods for extra security.

Flaps:
I installed flaps too. But, I think using Flaperons would be much simpler and just as effective. If I built another ETM, I would go that route.

Rudder/Elevator Servos:
As seen in Wavess photos, moving them back to the tail area is a sweet way to go. Use mini HS-81's (MG's might be best). I recommend adding a servo saver to the rudder servo since this is a steerable tail dragger. BTW, I stripped the elevator servo once when the model stuck in the grass on a slow taxi and innocently rolled over (the elevator has a lot of mass and it popped the servo on the forward fall). So, a servo saver on it might be good too.

Photo of servo saver on ETM shown below.

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[Wavess]

Rudder/Elevator Servos:
As seen in Wavess photos, moving them back to the tail area is a sweet way to go. Use mini HS-81's (MG's might be best). I recommend adding a servo saver to the rudder servo since this is a steerable tail dragger. BTW, I stripped the elevator servo once when the model stuck in the grass on a slow taxi and innocently rolled over (the elevator has a lot of mass and it popped the servo on the forward fall). So, a servo saver on it might be good too.

Photo of servo saver on ETM shown below.

Yes you´re right on servos comment. I did not like the hitec hs81 for this tasks, but I had them laying around and decided to use them, also I´ve experienced a bad neutral behavior on them. But once they brake I´d change them for different ones.

Now I´m thinking were to place my AV stuff

[Mr.RC-Cam]

Now I´m thinking were to place my AV stuff

Once you've installed it, we're going to need to see photos of all that.

[Wavess]

BTW does anybody knows which size are the 4 firewall screws that go into the blind nuts? I realized that they are Whitworth and not Metric, would like to order some replacement screws.

[Gary Evans]

BTW does anybody knows which size are the 4 firewall screws that go into the blind nuts? I realized that they are Whitworth and not Metric, would like to order some replacement screws.

I haven't heard the term Whitworth, which is a British standard, since back in the 50's when I was riding British motorcycles. The ones that came on mine are 6-32 U.S. thread or close enough that they fit that size thread gauge.
I also have an Electro under construction waiting the guts and video equipment out of the current FPV EasyStar whenever that should past away.
I used the screw on wing mod explained in this article.
http://tinyurl.com/34px7x
I have read that the tail wheel control arm connection to the rudder is a weak spot on hard landings so made the following change.

1) First layed up a multi-layer fiberglass sheet on wax paper and then cut out the desired size.
2) Cut out the Monokote under the reinforcements and soaked the balsa with thin CA for extra strength.
3) Epoxyed the reinforcements in place and drilled for screws secured with nuts.
My pics were too big to upload but can be viewed here.
http://tinyurl.com/2vqgry
I copied RC-Cam and Pibb's camera/Tx location in the wings since it's perfect. Thanks you!

[Wavess]

I haven't heard the term Whitworth, which is a British standard, since back in the 50's when I was riding British motorcycles. The ones that came on mine are 6-32 U.S. thread or close enough that they fit that size thread gauge.

Whitworth? I learned on my engineering bachelor studies, I didn´t know that there were another US standard.
BTW how the heck invented this standards? Wouldn´t be easier to go with the same metric for everyone??

[Mr.RC-Cam]

Wouldn´t be easier to go with the same metric for everyone??

When I was in grade school (USA), there was a huge effort to teach us metric for a planned national conversion from the US standards. It's decades later, and other than the auto industry, there is little interest in using metric components in mechanical assembly. The only visible residual from that program is that now all packaged foods include US and metric meaurements and our speedometers have kph in ghosted text. The foot based measurements are still king around here.

You'll have to push out the blind nuts on the firewall to relocate them for your new motor mount. So, toss the old ones, and their nasty english threads, and install metric equivalents. That should solve it.

[Gary Evans]

The British standard "Whitworth" is I believe based upon the width of a horses hoof and equates to nothing else.
The attempt to convert the U.S. to metric was as it turns out financed be Sear Roebuck who doubled their hand tool sales by requiring every U.S. mechanic to have both sets of wrenches.

[Wavess]

You'll have to push out the blind nuts on the firewall to relocate them for your new motor mount. So, toss the old ones, and their nasty english threads, and install metric equivalents. That should solve it.

The problem was that I did that already and forgot to replace them, I used the stock ones . But fortunatly I´ve placed an order to an US store with the measures Gary wrote before, so problem solved.
Thinking on were to place all my AV equipment, I have almost decided to start up with the camera under the fuse and move on if I don´t like it there. The sequence of equipment starting from the nose would be:

Motor - ESC - GPS - AV lipo + 5V reg - OSD - 868 rc receiver - Tx video

As attached below, I doubt to switch positions between rc receiver and TX video, also I´m considering on using another TX video omni antenna, this one

http://www.antenex.com/index051206.htm

the only "problem" is its weight around 5 ounces, but I´ve read about its great performance.

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[W3FJW-Ron]

You'll probably save about 3 oz if you dump the plastic case and repackage it your self.

[Wavess]

After thinking a lot about where to place my AV equipment, I finally decided to go with the wings. Transmitter on the left side and camera on the other hand.
I wasn´t very conviced about placing the camera under the fuse, this would give me a propeller vision, that I personally don´t like, so keeping the camera on wing´s right side would solve this for me, but unfortunatly I´m not going to have a clear field view when I look at the left, I suppose that with whatever combination with Pan&Tilt, I can see some "left" ground.
The other reason was that the distances that I wanted to have between components, were not enough for my purposes, placing all in the fuse, so I bet this would be the best solution for keeping apart video TX and r/c receiver.
So first to do was to run a long wire for my TX, this was difficult for me and I had to remove the flap servo for doing a little easier.
After I cut the balsa I needed to place the Tx inside the wing, but I placed with my whip towards the sky, not to the ground . With this I get rid of possible blind spots.
After all this I liked the idea MR.RC-CAM used with his mic, and I did something similar. I´m using Tiny Mic, weights few grams very nice mic:

http://www.dpcav.com...mp;bestseller=Y

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[ThomasScherrer]

hehe, looks abit like my plane :-)
http://www.webx.dk/r...ick/page_01.htm
please see those pages might give you a few ideas.
use thinn coax cables for video, local decoubling capacitors near GPS and near video TX,
I used 470uF, helped on transient responce.
I used twisted pairs for serial and power to gps, to save weight and minimize radiation and reflections.

Rule 1:
in any electronic unit/solution,
it is most uptimal to have as much distance as possible from noise generators to noise critical units.

in my case I have GPS in one wing tip, and Video TX in the other (2meter distance),
Cam is centre located and RC rx is in fuselage, near OSD,
I double checked no range deduction carefully, you know I always expect microcontroller boards and cams and such to generate bad carma into my RC rx, in my case I found no problems, I also have two 3A SBEC, one powering 6 digital servos and RC RX,
the other all FPV gear.

I suggest you test range carefully before flying long range, make it possible to power on/off all FPV gear seperatly,
so you can check absolutly no range reduction from this stuff.

I like the way you think about all possible combinations of trouble before installing anything into the plane.
it is often seen people just install the FPV gear, test, get problms, try and try, until it almost works,
better planning = better result, and less redo.

[Wavess]

Thanks about those kind words Thomas.
Since I´ve already installed a 3 wire twisted cable, I´ll go ahead and test it, as you said I was thinking on using a thin coax for video signal but didn´t have time during the week to buy it, and the show must go on .

Before doing long distance with a new plane, I always do a carefully check and go step by step.

Seems you don´t have pan&tilt movement on yours, that helps me a lot for taking references, and makes FPV cooler.
Do you think those green toroids you´ve got on the fuse help something? There is no much distance there, plus for my personal experience, it´s better to use twisted wires, but that´s not a scientificly based statement

Edited by Wavess, 01 March 2008 - 03:07 PM.

[ThomasScherrer]

I allready use so many channels, 6 digi servos and motor = 7
1 for OSD = 8
my TX can only handle 9 ch, in good old PPM mode, so I think that is why I dont have pan tilt,
I have learned to know the landscape quite well where I fly, and my OSD show me arrow to home,
so I dont get lost again :-)
I could connect the flaps and even ailerons to one channel each, I dont use butterly brakes anyway,
this will free alot a channels for pan tilt, I could also just simply add one more receiver so no more excuses.

the green torides was simply supplied with the Hyperion SBEC supplied with the plane,
so I did not remove them.

I have access to some REALLY cool thinn and flexible coax, it is also light weight,
and specially designed for video, so let me know if your installation have any stribes or issues,
I'll send you a few meters to play with for free, you can PM me with your postal adr.