700 My New T-Rex 700X Build

[trainrider06]

Hi Rodney, thanks for the feedback.

I'm planning to go to my workshop today and seriously test out the options for what I consider the best cable runs. I measured up the Axon and the base gives 12cm2 area to stick it down with and the two edges only half that, so it needs something extra to satisfy me that an end mounting is secure enough. Up to now, I've been thinking of installing it with no servo lead extensions but it's beginning to seem that won't be possible up front. Rear mounting is the only position I see works on that one but then the ESC and Rx. wires need extending instead.

I'm not under pressure to rush this as I've ordered up a clever box of tricks to programme the ESC. It also says in the downloaded ESC manual that one shouldn't power it up for the first time with anything other than fully charged flight batteries. If I hadn't read that, I would probably have been tempted to start working with my small battery just to give power to the gyro, so better that I haven't powered the heli up yet. The Axon can take its power supply from the USB to update firmware and register the unit with the software for use. Better than my Spirit Pro.

I'll keep you in touch with developments.

Myself I would much rather use extensions for the RX and ESC than all three servos just seems a little less extensive to me hehe...

- - - Updated - - -

Hi all, here are a couple more photos of another option that works without extending any of the leads from what I can see at the moment.

#001a View attachment 17016 #001b View attachment 17015

It's all temporary with nothing checked for accuracy as to which connection is plugged in where. The tail boom has a +5 degree angle from the ground so, of course, the gyro needs to be parallel with the boom and main rotor rather than the ground as it is in the photos.

Ah well done Phil! I like that mounting area also! I'm with Steve on the extensions especially with those bigger choppers and the what looks like 220 volt cables used for the servo's and such!

- - - Updated - - -

That looks like a pretty good option Phil. I managed to install the Vbar in the forward position without any extension leads but the end orientated connections helped.

Today's good news.. i think I've sorted out the spare parts for my repairs. I've found someone selling a new unflown 700X airframe + blades and motor for a decent price. It's more than the spares would cost me but I dont have to wait for stock and it gives me a whole spare airframe plus I can perhaps sell some of the bits that i dont need (like the motor etc.) I'm keeping my fingers crossed until i see it firsthand but in the photos it all looks as new.

Hope that works out Steve nothing more sucky than waiting on parts!

 

[Heliman450]

Hi Rodney,

At first I also thought that the servo wires looked great. However, the rubber covers at the end seriously restrict the flexibility to curve them into the gyro pins. In addition, the black cover is only protection and the three wires underneath seem to be much thinner than a 'normal' servo wire. The end result is that it makes it much more difficult to run them through restricted places. Of course they are geared up for the cable runs shown in their diagrams for their own electronics. When it comes to other products it's a different story as I've discovered. It's all part of the fun of the hobby

The ESC power/signal cables run nicely across the top of the batteries and I only need to clip them up neatly.

I've found a location that seems to work well for all the wires as supplied even when I won't need them. I'd really like an option of making my own custom wires that fit properly. I guess I'm a bit paranoid when it comes to cables, I hate them looking a mess (not only from the hobby).

My task for this weekend is get them fixed ready for powering up and programming the electronics when I get my ASBOX to programme the ESC.

Bye now!

 

[Smoggie]

Your right Phil, the wire lengths and routing are optimised for a FBL with 'end entry' rather than 'top entry' like the Axon or Spirit. Fortunately for me the Vbar has end entry servo connections in the main processor unit, so it all worked quite neatly. I'm sure you will figure out a neat solution.

I partly stripped my 700X down to identify and remove the busted bits and it's been sitting since on the naughty shelf while I sulked. I'll get back to it this weekend and get the FBL and receivers changed out. That way one by donor airframe arrives next week it should be quick job just to transfer the bits accross.

My lemon Rx diversity satellite receivers arrived:

I think these will be going in all my helis and planes from now on. They are basically two receivers in one tiny satellite case, the circuitry in the sat automatically selects whichever antenna is receiving the best signal and can switch between them whenever reception changes. So with two of these sats installed i have effectively four receivers and the antenna can be located in four different parts of the heli so as to always get getting the best signal.

 

[PLANETGETLOW]

Your right Phil, the wire lengths and routing are optimised for a FBL with 'end entry' rather than 'top entry' like the Axon or Spirit. Fortunately for me the Vbar has end entry servo connections in the main processor unit, so it all worked quite neatly. I'm sure you will figure out a neat solution.

I partly stripped my 700X down to identify and remove the busted bits and it's been sitting since on the naughty shelf while I sulked. I'll get back to it this weekend and get the FBL and receivers changed out. That way one by donor airframe arrives next week it should be quick job just to transfer the bits accross.

My lemon Rx diversity satellite receivers arrived:
View attachment 17021
I think these will be going in all my helis and planes from now on. They are basically two receivers in one tiny satellite case, the circuitry in the sat automatically selects whichever antenna is receiving the best signal and can switch between them whenever reception changes. So with two of these sats installed i have effectively four receivers and the antenna can be located in four different parts of the heli so as to always get getting the best signal.

After somebody here said that's all they use was Lemon Sats, I put two on my Goblin 380, so far so good.

 

[Heliman450]

Hi all,

Here's the next group of photos getting ready for the great 'power-up' asap next week. I'm putting a question to BD about the connections on the Axon. Their text doesn't agree with the software and the ID on the unit itself. Software says pins are 1 to 10 and the unit has A to D and 1 to 6 so I don't want to just go sticking things in the wrong hole as trial and error (pardon my French). I also need to know which port the EX-Bus connection goes into between the Rx. and gyro. Great fun, hey?


#1 #2 #3 #4

Photos 1 to 4 show the path of the ESC wires through to the back. Photo 3 shows there's a cable tie in the central hole to prevent the wires slipping back into the centre towards the main shaft. As an extra precaution, I also put a fine cable retaining wire across the frame's width to prevent them from touching the rear battery. You'll need to look closely to see it, the twist tail's between the wires and highlighted by the white of the battery.


#5 #6 #7

I removed the bracing support as shown in photo 5 to give easier access and labelled up the servo wires to show them up better for the 'photo-shots'. Fortunately, I don't need that step any more during the assembly process


#8 #9

Photos 8 & 9 show the gears fitted with Steve's recommended position for the 0.5mm thrust washer under the centre bearing. It does line the gears up properly with the pinion. As there's no fore/aft adjustment with the motor, what I thought of as feeling a bit snug is how it is. I suppose it's something that will ease up a bit as the gears run-in.

Bye for now!

 

[Heliman450]

Hi all, latest update on things.................

When I picked up the heli in the time-honoured way using the rotor head, I noticed what felt like a 'clunk'. I checked the play on the main shaft to find that it had what I thought of as excess play. Remember that as the heli spools up the weight is taken on the rotor disc and down the main shaft. This actually returned the main gear almost back to the misaligned position in relation to the motor drive pinion. My solution was to replace the 0.5 mm thrust washer for the 0.8 mm option. The pack also contained 0.9 & 1.2 mm washers, too. In my view the 0.9 mm was just too snug giving no free play at all as far as I could tell. Now, there's a bit of play but not as noticeable as previously.

I also fitted a guide for the gyro to ensure it goes in with the correct orientation to the rotor and tail boom. This is +5 degrees from the horizontal and as you can imagine when fitting something only 3 cm long inside the frame this was quite a challenge. I trial fitted the tail servo arm and it will be well clear of the gyro plus cables when fitted. It will be pretty much buried inside the frame so I really do need to know which connections go in the different positions as it's all a bit tight in there.

All frame screws are 'glued-up' apart from those I still need loose for refitting the tail boom. I took out one at a time and tightened them up. There were a few that weren't as consistently tight as most others, so I think the exercise was well worth doing in one session.

I'll take some photos later on.

Bye!

 

[Smoggie]

Well spotted, to be honest I'm not 100% sure which shim I put in mine. There was a bit of play so I grabbed one that looked 'about right' and it fitted perfectly leaving no discernible play, I guessed at 0.5mm but it may have been thicker.

I started getting by 700X ready for the arrival of the donor airframe. One thing I'll spend some time on is sizing the ball links, they are all on the tight side. When I was putting it together I thought they were a shade tight but I was keen to get it in the air so I left them (me bad). I have the opportunity to 'do it right' so I'll give them a bit of a ream out for a better fit.

 

[Heliman450]

Hi all,

I got the feedback from Bavarian Demon. Very good to get the response on the first working day after posting it including a further response to clarify the EX-Bus part.

The default listing in the software is for Futaba. Ports 1 to 5 are for the servos (#4 is for the fourth servo in a 90 degree swash). Ports 4 and A become spare to be used as power and 'AUX'. Other ports can also be used for power. Finally, the EX-Bus connection goes into the B port as a normal 3-wire patch cable connected to the EXT port on the Rx. By the way, it's clearly shown that the throttle goes into port 6, so no query on that score.

I'm now fixed to go ahead with the wiring, just waiting on delivery of the ESC interface.

 

[Smoggie]

I've still not got my donor airframe so i cant make much progress with my repairs but I have swapped out the FBL for another Vbar. I also reamed out the ball links as they were all on the tight side. I didnt have the correct size ball reamer (4.7mm) so i made my own by mounting a spare ball in a pin vice and dremelling a slot in it. The edge of the slot makes a sharp edge to ream out the lonk. It woked almost too well, only a few turns were needed to shave enough off the long to make a perfect fit.

Here's the tool:

 

[Heliman450]

Hi Steve,

What is the modified ball screwed into? That's what makes it so cool.

 

[Smoggie]

The thing that it's mounted to is a pin vice (Google it) its a hand tool for holding small drills for fine modelling work. It has a collet type jaw which clamps on the threaded part of the ball. It actually worked better than any of the 'real' ball reamers I've owned.

 

[Heliman450]

The thing that it's mounted to is a pin vice (Google it) its a hand tool for holding small drills for fine modelling work. It has a collet type jaw which clamps on the threaded part of the ball. It actually worked better than any of the 'real' ball reamers I've owned.

Cheers Steve, I didn't realise that the pin vice is the pictured holder. I thought it was something you'd used to hold the ball steady in while you dremelled it. I'll see about getting a couple of them for future use.

Still no ESC programming box yet.

 

[Smoggie]

I have a fair number of such tools from my balsa modelling days, they come in useful for sure.

So I'm now the proud owner of two Trex 700X's.. Well i suppose to be more accurate maybe 1 3/4 .. My spare airframe arrived today, it's all mint and clearly the seller wasn't lying when he said that it had never been run. All i have to do now is transfer the parts accross and set up the replacement FBL. Set up should be as simple as downloading the settings from the old FBL and uploading to the new. I'll be sure to give it all a really thorough check over before committing aviation again. I'm expecting to have knocking knees when it comes to flying it again. Maidens dont normally worry me at all but not knowing the precise cause for the crash is a concern.

I'll be sure to do videos!

Here's the new airframe just unboxed:

 

[Smoggie]

I was just checking my GoPro clone camera and found a still shot I'd taken on the day of the maiden:

 

[Heliman450]

Hi Steve,

Fingers crossed that there are no other problems and all goes well with the transfer of parts and maiden flight. Have a good check over whether the seller built it well and glued the bits up properly.

 

[D.O.G.]

I was just checking my GoPro clone camera and found a still shot I'd taken on the day of the maiden:
View attachment 17065

Damn, it seems to me that the 700X is alot bigger then your Agile

 

[Smoggie]

So that's my 700X rebuilt, set up and ready to go. The changes I've made to prevent a recurrence of the problems I had last time are:

• Swapped out the FBL for another Vbar Silverline
• Swapped the two Spektrum satellites for two Lemon Rx diversity satellites.
• Added two 4700uf capacitors to protect against voltage fluctuations

Sat #1. note two 'diversity' antenna:


Sat #2. Antenna routed forward, one on either side, also note the two capacitors



Nothing to do with the crash but to make the super lightweight (and super fragile) canopy a bit more robust and less prone to cracking during fitting and removal i added some carbon fibre patch reinforcing around the mounting hole positions:


Re-maiden tomorrow, weather permitting

 

[Heliman450]

Hi Steve, well done! Fingers crossed for the weather and a successful maiden flight.

You'll need to update your list of helis in the fleet.

 

[trainrider06]

Man you two pro's are doing some fine fine work and there is great info to be had here! Love the detailed pictures and descriptions!
Steve I like the sound of those Lemmon RX's that sounds like a very nice setup, and as you say the two on it gives a 4 power search detail to the system, and that is what counts with those big birds!
So those just bind right up with Spektrum radio's?
Ah man Steve you really know how to hurt a guy, those two heli's in the shot are stunners! Beautiful machines!

Phil your photo and descriptions are outstanding! Great shots of your work and setup of the wiring and such!
This is some great stuff from you guys!

Good idea with the canopy supports Steve, that reamer is a classic too!

Although this company is U.S. based I have used them many times for small modeling tools! Can't beat em!
Here is the link to check out for some tool porn!
http://www.micromark.com/default.as..._cn=WK_Brand&gclid=CLy9x8ers9ACFQiQaQodFIcPfw

 

[Heliman450]

Hi Rodney, thanks for your words of support. In my case, I think 'pro' is somewhat overstated. This is my first exposure to modelling and lots of stuff is new to me. I've always tried to do the best possible job whenever I've taken something on and part of that is having the right tools. I saved your link to the small tools specialists and will probably seek out something more local if possible for my first step as I always like to look around before buying. I could see at least 20 things that would be great to have in my toolbox 'just in case'

One thing that I've enjoyed about my winter project is sharing the activities here and I suppose that the number of views reflects interest by others, too. I never expected my build to be quick and it was a big boost that the Axon gyro turned up quicker than expected. I think that Steve's inclusion of his build (and unfortunate maiden) has given viewers the fast-track option.

I'm not becoming impatient just yet, however, the wait to get hold of my ESC programming box is a pain. If it doesn't turn up next week I'm going ahead with the next steps. It would be nice to video the maiden using a Soloshot3 but they still haven't released it yet and are hoping to start first deliveries before Xmas, we'll see!