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Old Nov 30, 2011, 04:34 AM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
Joined Dec 2005
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Quote:
Originally Posted by fcbflyer View Post
But first make sure the 98mm is the right CG.
This is the key issue; that makes building a ballast tube so tricky. It may turn out after flight testing that the CoG ends up WAY back from that (or not): any ballast plans need to build in that possibility. A rear-ward located tube with spacers doesn't seem so stupid to me.
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Old Nov 30, 2011, 01:07 PM
Detail Freak
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Harbor City, CA
Joined Oct 2003
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If I don't know for certain the CG, I build the tube a little long in the aft section (so that the center is at least 10-12 mm aft of furthest know spot, and then I can add temporary and even permanent spacers in the back of the tube afterwards.....

A too forward tube can't be fixed.

R,
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Old Nov 30, 2011, 01:09 PM
Detail Freak
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Harbor City, CA
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Quote:
Originally Posted by Ian Thompson View Post
Just had another email from Carlos. He uses the joiner & the wing tubes for ballast. Doesn`t use the fuse tube at all. 98 mm is where his CG is..he told me 94-98 mm for the CG. He also uses a 2 cell lipo & regulator..
Ian
Thanks, Ian-

Can you get more specific details of the CG arrangement Carlos is using?
Brass or steel for both, cast lead, etc??

Thanks,
Target
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Old Nov 30, 2011, 02:47 PM
War is over (if you want it)
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Thousand Oaks, CA
Joined Mar 2004
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I try to make ballast tubes ~10mm long in the back and then put a slightly over-diameter EPP "slug" in there to set the rear position and prevent rattling as well as slamming/breaking the rear cap. The EPP can be removed if needed with double-sided tape on a slug. Drilling a large hole in the EPP with a brass tube allows for a large range of motion for adjustable ballasts on F3J ships.
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Old Nov 30, 2011, 08:48 PM
Registered User
Australia, WA, Perth
Joined Apr 2006
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All Carlos wrote was total ballast about 1300g.. I dont really want to keep bothering him. He didn`t clarify the reverse differential but did give me his launch settings..
I will be starting on the Toba next week. I am going to use all Hyperion servos.. DS095`s in the wings ( I have some cool alloy mounts with 3rd bearing ) & DS 13 ACB`s in the fuselage.. The wiring loom I got with my model is wrong the Flap leads for the wing are too short.. So I guess I will be getting some soldering practice...
Cheers
ian
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Old Nov 30, 2011, 10:32 PM
Thermal Wrangler
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Launceston Tasmania
Joined Mar 2004
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Sticking a towhook in it Ian?
I only ask this to gauge whether the glider can take a hard launch.

regards,
Chris.
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Old Nov 30, 2011, 11:51 PM
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No problem for a hard launch. Steve Keep helped the China Team to hard launch the TOBA in the WCH.
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Old Dec 01, 2011, 01:28 AM
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Australia, WA, Perth
Joined Apr 2006
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My toba will be used for (trying to :-) ) learning F3B.. So yes it will be getting a tow hook.. The wing joiner is fairly large so I`m picking it will take anything I can give it..
Ian
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Old Dec 02, 2011, 01:56 AM
Thermal Wrangler
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Launceston Tasmania
Joined Mar 2004
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Thanks Polar Bear, Ian.

This sounds like a good F3B entry-level model.

FYI Joiners are easy to make rigid it's the spar design and joiner box to spar interface that's hard to get right.

My last Chinese "F3J/B" ship was a Zoom Model Valenta Storm clone. It was very "rubbery" under stress despite being full-carbon. I sold it on and never go the point where I could check out its innards.

Chris.
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Old Dec 06, 2011, 07:08 AM
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Australia, WA, Perth
Joined Apr 2006
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Well I`m ahead of Target already..lol..(yes it is a competition ) I have had to revise my fuse servos..the Hyperion DS 13 SCD`s are just abit too big.. DS11 SCD`s are on their way.
Using the Hyperion 095 wing servos & the ally mounts mean that I wont need the bulged flap servo covers so i will make my own out of pre cured carbon sheet..The ailerons wont need the bulge either but will need the pushrod fairing.. A solution is in the pipeline.
I bought a wiring harness with my plane.. to be honest it was a waste of money...The fuse harness is way too long, The aileron leads are 75mm too long & the flap leads are 100mm too short.. I have notified the shop I got my plane from so hopefully these issues will be resolved. I made a new harness from scratch & it is 38 grams lighter than the bought one..I got to use my new soldering iron too... life is full of bonuses :-)
On the V tail the horns aren`t even from the end of the surface to where they turn 90 degrees up.. I had to trim a bit out of the fuse on 1 side & it meant that the tail cone cutouts aren`t the same..no biggie but a bit more work.
The fuse joins on my model are a bit rough..there is a bit of flashing that needs to be smoothed out..
The wing joiner seems to be a little loose in both the wings & the fuse... I will consult with someone more experienced...
Will take some pics & post soon..
Ian
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Old Dec 06, 2011, 07:12 AM
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Australia, WA, Perth
Joined Apr 2006
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Hi Chris.. I had chicken at a chinese restaurant..it was rubbery..
they said thank you very much
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Old Dec 06, 2011, 03:05 PM
Thermal Wrangler
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Launceston Tasmania
Joined Mar 2004
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If you've got a sloppy joiner, drizzle thin Zap or similar along the length of the joiner, immediately wipe with a rag. Apply accellerator LET IT CURE then re-fit. You might need to lightly sand it as accellerator tends to bubble.

Rinse and repeat until it fits...this works for me.

Servo covers from clear plastic sheet from most shop packaging also works for me. It'll also show off your bling servo frames ;0)

Chris.
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Old Dec 11, 2011, 08:56 PM
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Australia, WA, Perth
Joined Apr 2006
124 Posts
My wing hasn`t got the control horns installed..What is the best glue for attaching these? With the flap horns do I drill through the flap stiffener to take the horn or cut the horn off & butt it to the stiffener?
cheers
Ian
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Last edited by Ian Thompson; Dec 11, 2011 at 09:04 PM. Reason: additional text
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Old Dec 11, 2011, 10:59 PM
Detail Freak
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Harbor City, CA
Joined Oct 2003
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You can do it either way, Ian.
If I were in a better mood, I'd check and see how the factory did the ones on the copy I have.
It likely doesn't matter so long as you get a good foundation of epoxy and chopped fibers in there, but, optimum would be without harming the spar at the LE of the moving surface.
Whatever you do, make yourself some quick and easy jigs that have a piece of music wire and scrap of plywood. Make sure the holes for the clevises are well-matched flap to flap and aileron to aileron, with regards to their respective hingelines.



R,
Target
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Old Dec 12, 2011, 03:19 AM
F3B
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Warwickshire, England
Joined Sep 2006
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Quote:
Originally Posted by Ian Thompson View Post
My wing hasn`t got the control horns installed..What is the best glue for attaching these? With the flap horns do I drill through the flap stiffener to take the horn or cut the horn off & butt it to the stiffener?
cheers
Ian
It saves you from having to take them out!

You will probably end up with better geometry and almost certainly better quality horns.

I always make a jig. You don't won't left and rights to be different, as target says.
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