Tragi 801 - Page 5 - RC Groups
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Feb 19, 2010, 03:31 AM
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belouder's Avatar
Finally weighed it tonight-67.8 oz. And tomorrow I'll be taking a couple of grams of nose weight out-using a "real" balancing tool showed it at 113-needs to move back some.

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Feb 19, 2010, 11:53 AM
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SmokinJoe101's Avatar
Originally Posted by belouder
Finally weighed it tonight-67.8 oz. And tomorrow I'll be taking a couple of grams of nose weight out-using a "real" balancing tool showed it at 113-needs to move back some.

Nice,, hey like I said 67 - 68oz no prob on a standard radio install. I like mine just a tad nose heavy for me it lands better.

Feb 20, 2010, 02:42 PM
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R.M. Gellart's Avatar
Well, even though most guys are getting nice weights, I am trying to get the finished ship squeezed down to 65 ounces if I can. The first real change is reworking the wire harness. I started with the fuse side of the harness and detached all the wires, twelve, and replaced with 18 gauge + and -, single set per side and 28 gauge signal wires. With some slack wire to make sure of easy connection at the RX end, the new set weighs a quarter ounce less than just the wires do. The other harness mod will be the signal wires in the wing, which will save another .25 oz, so total is about .5 ounce. Not dramatic, but I am trying a new wiring set up on the ship and this will let me see what I can accomplish here. A couple pics for the DB9 and wires.

Feb 20, 2010, 05:48 PM
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R.M. Gellart's Avatar
A couple more pics of the wire harness together and ready at least in the middle. The remaining works involves the RX end, but will not do that till near final assembly.

Feb 20, 2010, 05:50 PM
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Looks nice Marc!
Feb 21, 2010, 12:49 AM
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Smurfmacaw's Avatar
Nice job. The only way I could make solder joints that nice is if I had four hands.
Feb 21, 2010, 05:27 AM
Registered User
D9s are heavy you could dremel off a few more grams by reducing the D9 flanges a bit.
I do it the lazy way and use a multiplex plug.
I hace dremelled down a D9 in the past.
Taper to a rounded end at each end and thin the side flange.
Good luck any way.
My Tragi is still stuck somewhere but will get to me eventually !
I look forward to reading about how you find the manufacturers settings.
Feb 21, 2010, 10:51 AM
Dragons, WindMills, all Same
jcstalls's Avatar
Sweet work George.

Nata on the MPX plug and better on the D9 as pictured there is separate power to each wing panel as the MPX cannot do but the D9 can. And, a few grams much less a few ounces either way on this ship will really do what? IMO

Feb 21, 2010, 11:06 AM
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R.M. Gellart's Avatar
Smurf, it really is not that hard, especially using a single power wire per side on the fuse plug. The biggie is just having something that holds it secure. I have a soldering jig I have had for years, but it would not hold the DB9 secure. So I just put a pair of forceps in that jig and that was solid and then I could orientate it the way I wanted and it worked fine. A friend of mine, Ron Mong, and I have talked a lot about doing this and I had about talked myself out of it because I thought I would screw it up. I got it done and it was good for the soul. Sometimes, we need to stretch the environment.

More to come!

Feb 21, 2010, 11:08 AM
Woodstock 1's Avatar
Nata? North Atlantic Treaty A....?
Feb 21, 2010, 12:24 PM
Registered User
Hi again,
if you wish to dual up the power supply would there not be value in bridging across the two positive and of course two negative terminals.
If a connection to the D9 terminal lets go you still have power through the bridge to the other terminal.
Your soldering looks good and clean to me so it probably wont let go anyway.

when I was flying free flight we saved weight in many small increments to make a meaningful saving. But I think you are right, on this plane, I dont think an ounce here or there will make a noticeable difference.
Feb 21, 2010, 01:00 PM
isoaritfirst's Avatar
There was a discussion about how best to wire through DB9 on another forum a while back.
The conclusion was that having individual wires was the best solution (not for weight) but for redundancy, having each servo independent means that should there be a problem with a connector you lose one servo and you know about it. The model should still be relitively safe to land and then repair the problem.
Coupling up leads means that one wire fails and the other takes over - you don't get to know you have a problem until the second wire fails - resulting in a complete wing failure and more likelyhood of having a problem landing.
So bridging doesn't create a safety margin - but takes it away.
I have gone back to 3 wires to each servo in my builds since.
Feb 21, 2010, 04:40 PM
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R.M. Gellart's Avatar
I will admit, I had not put that much thought into redundancy of the power source for the wing guys, but i think that unless you have a really tight install and can only squeeze one wire, then two is nice.

Well, got the DB9's cleaned up a bit per Sandist and it did knock a few grams off for sure. Got the plugs sealed up with e-safe silicone for protection, and did one other thing. I usually like a lot of down throw in my ships, primarily for bunting over on launch and knowing that I have plenty of flap to elevator compensation and the down throw to know i can stick the spot. In looking at the slot that allows the alignment pin to travel vertically in the vertical stab, there is a shelf so to speak that is about 3/32" below the lower edge of the alignment pin slot. So I opened up the slot to the shelf and found out that I was at a stop short of that shelf, no more down no matter what.

So I wrote a note to Heino (bet he is beginning to think I am a pain in the arse) and he said that the belcarnk was at a stop against the rudder post. So I disconnected the the rudder pushrod, and began to examine what I could see and feel in the ares. Well, the belcrank is visible just above the rudder pushrod opening and it was pretty evident that the slot would be just above and centered relative to the rudder pushrod opening. I started with a t-pin making an outline and then opening the slot up. I was dead nuts and got the rest of the throw available without messing with the shelf in the vertical stab. I was kind of proud of myself right then. I realize that this is pretty easy, but hey, I got it done right the first time for once.

Feb 22, 2010, 08:22 AM
Registered User
I understand the concept of 3 wires per servo but in a 4 servo wing that is 12 wires
are you using a DB 15HD instead of a D9 ? They fit in about the same space.
Feb 22, 2010, 08:32 AM
satinet's Avatar
surely you don't buy a tragi and expect to have to dirty your hands with soldering the wiring loom?!

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