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Old Nov 17, 2012, 07:28 AM
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Australia, QLD, Beaudesert
Joined Jul 2008
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BJ, I Take it you mean before you put the wing together?
I ask you that as I am thinking I will put a little epoxy into the tiny gap that I have in one or two places at the joins, now that it is joined, as opposed to what I think you mean "at time of joining" To me there just does not seem to be enough contact area for the wing to have the strength, I know it is designed this way , and it obviously works!
I just dougt my workmanship in joining the wing, as it appeared to not be a very good join, the surfaces seemed to not be a totally flat, or straight,mating surface.
However I do realize that epoxy has a great deal of strength. Maybe I am just not used to light weight craft, it just dont seem rite!!
To be honest I am almost tempted to glass the joins, but that would just not be rite
I will look at it tomorrow when the epoxy has cured, and give it a bit of load.
Neal
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Old Nov 17, 2012, 05:45 PM
The wheels touch down FIRST??
BJ64's Avatar
Australia, VIC, Melbourne
Joined Jun 2009
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Yah - I gooed mine up pretty well on the adjoining surfaces before putting it together. But remember, I had to have my already-asssembled wing cut through at the joiners to get it shipped here from Perth. And I had to drill out the joiners and use some CF rod in place of that laminated plywood joiner bar.

And yup - the alignment is a bit iffy anyways.

What you can do is use masking tape on the top side of the wing joins, then patiently feed glue in from the underside and into any voids you may have (the tape stops it from oozing out the other side).

I used some Selleys SilkaBond - WBPU (water based polyurethane glue) - as it expands on curing. Use an eyedropper to get a bit of water in there first - helps to get the WBPU to expand. Then use a toothpick to force some glue in there. Watch the stuff, because it sticks like sh'it to a blanket and can make a real mess if you try to use too much at once. And don't get it all over the covering, as it's a pig to get off.

Take your time and feed a little in at the time. Best to put a good drop on a piece of scrap cardboard and use the toothpick like a dentist filling a tooth wood.

When you reckon you've got enough in there, tape over that that side of the 'crack' too so the join is completely sealed. The WBPU will expand out in all directions and make a fairly clean finish where it touches the tape.

Low-tack masking tape or that 'invisible' sticky-tape is good - it won't try to lift your covering off as much as normal masking tape will when you go to remove it.

If the opposite side still has voids in it, do the same thing in reverse i.e. tape the underside of the join, and feed the glue in from the top.

Just go slowly and sparing with the glue - don't get it all over the shop...

BJ
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Old Nov 17, 2012, 06:34 PM
Tim Lampe; Hobbico R&D
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Champaign, IL
Joined Dec 2009
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Yay! Got in a couple of flights on my Siren today. I thought flying was all over for the season, but we've had great weather here in Illinois the last several days, so I charged up my battery and took 'er for a spin. Perfect landings of course!

Way to go everybody on this thread. Crazy! This thread just keeps going and going and going. That's why I had to get me a Siren. Glad I did and congratulations to everybody here who keeps 'em flying.

Tim
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Old Nov 17, 2012, 07:15 PM
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Australia, QLD, Beaudesert
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Thanks BJ, what you are describing is just what I thought I would try, feel better that I am not alone though.
Though I will use epoxy 2 pack, I have th option of mixing it a little thinner or thicker, so I can feed it in ok.
The masking tape I use is perfect for the job.
I will start that later when I mix some epoxy for for the servos, which I am about to go and start, weather not great for flying today anyway!
Thanks for the advicce for the taping.

Tim, g'day,
Good to read you had some good flights, we get spoiled here, fly all year round!
Neal
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Old Nov 18, 2012, 05:45 AM
CSI
I promise, just ONE more order
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Del Rio Intl, Texas, United States
Joined Feb 2004
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I was also able to get a couple of nice flights in this past week. I am on my 2nd Siren. The first one, mentioned way back near the beginning of this thread, flew great. Unfortunately, I got a bit too slow after hitting the spoilerons and she snapped in on me. Hit the hardest, clay/rock strewn area in the area and shattered the fuselage to pieces. The wing didn't fair too well either. I was really bummed...she really did fly great. That big AXI motor up there with the folding Aeronaut 14x9.5 really hauled the mail. After a year, I just couldn't stand it anymore and ordered another one. It took me another year to finally put it together with the same motor, servo, esc setup from the first one. This one flies well also, but not quite as true as the first one. I flipped the switch on the spoilerons and found she has a sharp right turn from them.

I just spent the past 2 days carefully going over the entire airframe. I think it was the hinges on the ailerons not being the same. One is a bit less rigid than the other, so seems when it is deflected the hingeline moves up, raising the whole aileron up more than the other. It lifts the hinge up...the hinge isn't sticking well.
Also, found the aileron stock was way different between the 2. One was very soft balsa and bends easily, while the other is firmer and doesn't twist as much.

Sooooo, I spent all day today cutting off the old ones and replacing them with new, very hard, aileron stock. Got them all covered and re-taped into place tonight. Definitely much better in accuracy during the deflections.
Hope it solves the problem. Sure took a bite out of my weekend.

These Siren planes are definitely a 'hoot' to fly and I am quite glad I have one.
Ken
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Old Nov 18, 2012, 06:11 AM
The wheels touch down FIRST??
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Australia, VIC, Melbourne
Joined Jun 2009
25,387 Posts
They sure are, Ken

Say - you watching the F1 GP tomorrow/today?

It's a 6am Monday starter for us here across the pond..

BJ

PS - kinda freaky, but I'm eating a bowl of Chilli as I type (no, serious - I am)
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Old Nov 18, 2012, 06:44 AM
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Clifton, VA
Joined Mar 2003
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I too flew mine on saturday and plan to fly again today. Got 10 flts on her now since a week ago Sunday. Love the sound @ full throttle and high speed motor off passes.
I noticed that mine has a twist in the fuse and the wing and stab are therefore not parallel. U can see it in the air when flying. It flies OK but does look abit "off". Not sure it can be corrected.
Also the data logger suggests 15K rpm @ full throttle for 2 pole motor geared 4.3 to1. I will measure full throttle today to get actual.

Pat
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Old Nov 18, 2012, 06:54 AM
The wheels touch down FIRST??
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Australia, VIC, Melbourne
Joined Jun 2009
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What kV are you guys running the 4:3 to 1 gearboxes at? And what Amps are you pulling?

My HET should be 1100kV at no load, but it's only producing about half that swinging a 13x6.5 prop (and pulling mid 60's in amperage).

BJ
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Old Nov 18, 2012, 07:59 AM
Tim Lampe; Hobbico R&D
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Champaign, IL
Joined Dec 2009
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Quote:
Originally Posted by N2UMK View Post
I too flew mine on saturday and plan to fly again today. Got 10 flts on her now since a week ago Sunday. Love the sound @ full throttle and high speed motor off passes.
I noticed that mine has a twist in the fuse and the wing and stab are therefore not parallel. U can see it in the air when flying. It flies OK but does look abit "off". Not sure it can be corrected.
Also the data logger suggests 15K rpm @ full throttle for 2 pole motor geared 4.3 to1. I will measure full throttle today to get actual.

Pat
I noticed the stab saddle on mine wasn't completely flat - like had buildup from paint or resin, so I just sanded it flat. If your horizontal stabilizer is not parallel with the wing you could do the same - sand the high side of the saddle to bring the stab into alignment. We do this on our GP Rifles all the time.

Tim
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Old Nov 18, 2012, 08:01 AM
Tim Lampe; Hobbico R&D
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Champaign, IL
Joined Dec 2009
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Quote:
Originally Posted by BJ64 View Post
What kV are you guys running the 4:3 to 1 gearboxes at? And what Amps are you pulling?

My HET should be 1100kV at no load, but it's only producing about half that swinging a 13x6.5 prop (and pulling mid 60's in amperage).

BJ
1100kV sounds super low considering the kV of the two motors I've run (3600kV and 3200kV) with that gear box. Go check the Siren entry in my blog for lots of numbers.

Tim
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Old Nov 18, 2012, 09:02 AM
The wheels touch down FIRST??
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Australia, VIC, Melbourne
Joined Jun 2009
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Quote:
Originally Posted by KRProton View Post
1100kV sounds super low considering the kV of the two motors I've run (3600kV and 3200kV) with that gear box. Go check the Siren entry in my blog for lots of numbers.

Tim
Um...

I'm running direct-drive - no gearbox.

That's why I asked...

BJ
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Old Nov 18, 2012, 02:13 PM
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Clifton, VA
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Thanks Tim. The stab area actually looks good. There is a twist in my fuse that misaligns the wing in the wing saddle to the H-stab. Fixing it may require adjusting the stab mount.
Put 3 more flts on the SIREN this morning. On the 3rd flt (lucky 13?) the gearbox came apart in flight; fortunately I had enough altitude to bring her in safely. The front of the gearbox stayed mounted to the firewall and the rest of the gearbox came out with the motor. No damage it just unscrewed itself. The front half had locktite. Nothing on the back half.
Turnsout the rpm @ full throttle is pushing 19K+!
Can those folders handle that much RPM? Apparently they can.
What is their max rpm? My 12x8 folder is a Falcon CF.

Pat
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Old Nov 18, 2012, 03:58 PM
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United States, AK, Anchorage
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Maybe this has been answered already, but what advantages does a gearbox + inrunner combo have over just running an inrunner?
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Old Nov 18, 2012, 04:42 PM
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Australia, QLD, Beaudesert
Joined Jul 2008
594 Posts
Hi guya
Yellowcolorado, I hope someone chimes in with a more complete answer than mine! So what are they guys!!
Got the servos in yesterday, mucked up the elevator serro, a little moro down than centre, must have moved a bit in the epoxy when I taped it
Any way I will take the orrn off, and screw it the rod out a couple of turns.
And do the rods for the ailerons, todays work, before work!
Must order a couple of bats and plugs tomorrow, plan to maiden weekend after next, assuming the box and motor turn up,
Be in the air a lot earlier than I thought, is good!!
Neal
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Old Nov 19, 2012, 01:54 AM
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United States, AK, Anchorage
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Its all good neale. Ive always ran direct drives in all my planes so I wanted to understand the benifits of a gear drive. Does it produce a certain amount of power with less amps?? It seems as though it would be a limiting factor. Only ~700 watts of power that it can handle and another factor in the equation that may fail...
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