Author Topic:  Crash: My Kasama Faifa 90E rebuilding experience - Let's make it better  (Read 17034 times)

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Offline bathmagic

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Crash: My Kasama Faifa 90E rebuilding experience - Let's make it better
« Reply #150 on: September 29, 2014, 10:53:04 PM »
Great post Jason

Offline rchelijc

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Couldn't leave it alone..
« Reply #151 on: September 30, 2014, 08:49:36 PM »
Well, I couldn't.

End Goal: mod to allow movement of lipos front and back (a little) to better adjust CG.

Secondary goal: Perhaps fit other packs as well


First off, it wouldn't CG smack bang zero. From the previous post, you can see that the Lipo has very limited sagittal movement (I'm looking for the word that is opposite to lateral, but can't think of it). Yes my heli current sits like that on the ground..

[ATTACH=CONFIG]58060[/ATTACH]

...but so does the CG. When balancing with the twin peaks lipos, it sits exactly like that as well in mid-air. TommyBear reckons it's good for speed runs, but I like options, and not a big fan of one trick ponies.

Secondly, I was never quite happy with the original lipo mounting system anyway. Here's a quick diagram:

[ATTACH=CONFIG]58056[/ATTACH]

Diagram shows straps go through the frame slots, into the tray slots, and around the lipos. I initially had my reservations - it looks like the stress is on the frame, but the frame mounting system is pretty strong. Every crash has broken the CF lipo tray only, usually near the countersunk bolts. I think I do recall a strap breaking the thin CF piece on the frame, basically pulling and shearing it off in one of the crashes.

That gap between the tray and the frame really does allow some movement of the tray, and I think that plays havoc with the forces on the frame slots. Maybe not so much is Tareq flights, but a crash is many times higher in G forces.

Here's a real-life pic hopefully showing what I'm talking about (not my Faifa)

[ATTACH=CONFIG]58062[/ATTACH]


However, this is a different story I'm guessing:

[ATTACH=CONFIG]58058[/ATTACH]

It almost seems irresponsible to even do this, which is what I'm intending to do as per previous post.

I thought about grinding down the mounting Alu bits, and realised it could work. Here's a pic of how it's supposed to turn out.

[ATTACH=CONFIG]58057[/ATTACH]

The goal is to remove the gap. The bad is, in doing so there's a lot of hard CF-on-CF grinding. I like grinding, but I think not appropriate here. So I needed something that could compress and cushion, but also hard wearing, hence the compressed plastic bit. I found some nice tough plastic that's usually part of packaging.

Mind you, buy Aussie stuff, and you get good packing plastic. Whatever I bought that was Aussie that came with this packaging, was worth the $$$.

Here is the end-result - grinded down as flat as I could and flush against the top of the frame. The other good thing about the plastic is it will even out the pressure better as you torque down on the bolts against the CF tray against not-so-perfectly-flat alu mounts. So you don't have to grind perfectly flat - close enough is good enough.

[ATTACH=CONFIG]58059[/ATTACH]

I found without proper tools, the simple way is pliers (with cardboard to prevent marking) holding on to the bit, you cut off the better part of 1mm on both legs. Then you place the legs flat against a wide cutting disc of the dremel to finish off. In effect, turning the cutting bit into a flat circular grinder. Should do you good enough with this, eyeballing, and a micrometer.

Next, cut the appropriate plastic size so that any point of the CF tray that touches against the frame, has plastic sandwiched. Use a bit of CA to hold it in position (I used too much), and drill out the holes. I've found the best way to drill out holes in plastic this way, is to set the drill high speed, in reverse. That way it doesn't 'catch' the plastic, and make a mess, or create an even bigger hole in the CF underneath. Should be common knowledge but just in case it helps someone... there's little more to this technique, basically just ending by moving the drill bit around a bit to get rid of the plastic flash (since this technique melts the plastic as opposed to really cutting it).

[ATTACH=CONFIG]58061[/ATTACH]

Finally, all mounted up, cables facing main-shaft. The way I do series connections, it's really easy to strap the cables down against the lipos.

[ATTACH=CONFIG]58054[/ATTACH]


Plus, I can confirm that I can fit the Billowy 4400mah 6S packs as well. Plus have quite a bit of room, including being able to move the packs closer to main shaft for better CG.

Finally, for those with the drive to put the Faifa on diet, here are some weights, comparing the stock canopy vs the F-nine CF (lightest) vs the F-nine FG (heaviest).

[ATTACH=CONFIG]58051[/ATTACH][ATTACH=CONFIG]58052[/ATTACH][ATTACH=CONFIG]58053[/ATTACH]

Seems to work well. Only thing I don't like is, without lipos on, the ESC cables droop rather suggestively... hmm... I suppose for a guy it's a pretty good look...

[ATTACH=CONFIG]58055[/ATTACH]

With a clean mind, it reminds me of 'The Strain'..

By the way, all my straps are of the L size (scorpion and Mikado) - anyone got some Scorpion or Mikado straps in the XL size? Just need 2 - happy to get them off you if you live near or going the the AFF BBQ this weekend.
« Last Edit: September 30, 2014, 08:51:52 PM by rchelijc »
KASAMA SRIMOK 90E FAIFA - TJ [/SIZE][/B] VBAR HK-4525-UE     KASAMA SRIMOK 90E FAIFA - Ellie [/SIZE][/B] VBAR Pyro 700-52
PRÔTOS 500 [/B] FBL Brain HK-3026  PRÔTOS 500[/B] Stretch FBL VBAR HK-3026
MA X-CELL RAZOR 600E FBL VBAR 6S HK-4025-1100
Blade 400 RIP, mCP-X BL, MSR, nano-QX, Syma S006-clone

Offline billiano

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Crash: My Kasama Faifa 90E rebuilding experience - Let's make it better
« Reply #152 on: September 30, 2014, 10:19:22 PM »
Nice to see that you like your canopy from us.

Offline rchelijc

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Thong
« Reply #153 on: October 04, 2014, 01:15:29 AM »
Finally got round to replacing the lower battery tray, cut out of 2.5mm CF.

[ATTACH=CONFIG]58091[/ATTACH]

Mounted underneath - protecting the motor and probably adding a lot of frame stiffness and structural support as well.

[ATTACH=CONFIG]58092[/ATTACH]


Finally what she looks like from 'underneath'. Very thong like...


[ATTACH=CONFIG]58093[/ATTACH]


Edit: saved 15g
« Last Edit: October 04, 2014, 01:18:29 AM by rchelijc »
KASAMA SRIMOK 90E FAIFA - TJ [/SIZE][/B] VBAR HK-4525-UE     KASAMA SRIMOK 90E FAIFA - Ellie [/SIZE][/B] VBAR Pyro 700-52
PRÔTOS 500 [/B] FBL Brain HK-3026  PRÔTOS 500[/B] Stretch FBL VBAR HK-3026
MA X-CELL RAZOR 600E FBL VBAR 6S HK-4025-1100
Blade 400 RIP, mCP-X BL, MSR, nano-QX, Syma S006-clone

Offline Connor

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Crash: My Kasama Faifa 90E rebuilding experience - Let's make it better
« Reply #154 on: October 19, 2016, 05:00:34 PM »
that's terrible crash man