sdg111
Flight lieutenant
Posts: 85
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Post by sdg111 on Sept 23, 2012 22:04:18 GMT 1
Folks, I'm still waiting for all my spare parts to arrive, and have been doing a lot of reading re props, prop shafts etc. I'm now slightly nervous that even after my repair the plane may not:-
a) fly so well
b) have the same power
c) have the same initial characteristics
I base this on nothing more than what I have read on previous threads as I see others have had issues with similar relatively minor repairs.
Everything I've removed so far has been labelled and stored.
Is replacing the propshaft as easy as I'm thinking, i.e. undo the four motor mount screws, pull old shaft out from the rear, and re-insert new one from the rear, replacing spacers, washers etc in the same order they were removed. I presume it's quite obvious how the end of the shaft with the teeth sits/engages?
I'm assuming at the same time I should check the motor mount and firewall for damage.
I just don't want to spoil my plane with my first major(ish) repair.
Any advice appreciated.
Steve
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Post by luvofthagame on Sept 24, 2012 2:31:43 GMT 1
Yea, its that easy...you are correct in assuming you should re check the motor mount and firewall...I didn't notice my crack in firewall until motor mount pulled it out more...with my experience, its always the right side...check for a crack along top right of mount and along the bottom of motor mount shaft where it meets the plastic...then on firewall, right side where it protruded out into the screw holes...you have to tug on it good to see it...being the firewall is a pain to take off, I CA'd both sides of crack...worked very well...CA on motor mount was useless, would hold in flight...really sucks waiting on parts,lol...been there...
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sdg111
Flight lieutenant
Posts: 85
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Post by sdg111 on Sept 24, 2012 10:21:11 GMT 1
Luvofthagame, thanks a lot your reply. I'll check it all very carefully when I remove it. I should really remove it now so if they are broken I can order the parts now, rather than wait again should I find they need replaced. When you say right side are you looking at the front of the plane or from the rear?
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sdg111
Flight lieutenant
Posts: 85
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Post by sdg111 on Sept 24, 2012 14:11:11 GMT 1
Okay, I've gone and undone the nut at the front of the prop shaft and removed it and the clear plastic spacer. I pulled the prop shaft out from the rear and on doing so saw another metal spacer at the front. On pushing the shaft back through I have found and removed the metal spacer, two tiny metal washers, the one nearest the front has teeth at one side, and finally a thicker metal spacer.
So, including the nut I have six items.
Two questions please, are the washers and metal spacers inserted from the front (prop) end and what way is the metal washer with teeth re-inserted. Teeth towards the motor or teeth towards the prop?
Do I have the correct amount of hardware out from the gearbox?
The prop shaft was properly twisted, the threaded section sitting at an angle to the reat of it.
Any replies much appreciated.
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sdg111
Flight lieutenant
Posts: 85
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Post by sdg111 on Sept 24, 2012 16:58:46 GMT 1
Sorry to go on about this but advice seriously needed. I think my gearbox ring bearings have disintegrated, hence so many parts coming out of the gearbox housing.
From what I have read there should be only two bearings, one to the front and one to the rear of the gearbox housing. I have many more parts than that!!
I think I'll just fit a new gearbox to the motor and keep my old gearbox housing as a spare, assuming the bearings don't shred themselves again......
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Post by flydiver on Sept 24, 2012 17:41:13 GMT 1
When you are taking these things apart it's a good idea to take digital photos until you understand how they work.
Funny how no one has posted a photo of the parts laid out that I know of. This is a pretty common question....HINT HINT!
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Post by renard80 on Sept 24, 2012 18:53:28 GMT 1
If you're worried, it could be best to do as you suggest - go the whole hog and replace it. Relatively cheap for peace of mind! Mention made of possible firewall damage. That plastic firewall is a right PITA, prone to cracking and difficult to repair or remove. For what it's worth, some months ago I tried mounting a rubber cushion to spread the load and so avoid damage. I am pleased to report that it appears to have been successful, the firewall remaining undamaged despite a few head-ons and some more minor bumps. Another member did similar with a round rubber washer. Here's the link in case you wish to try similar when installing your new motor mount etc. supercubclub.proboards.com/index.cgi?board=tt&action=display&thread=4532&page=1 |
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sdg111
Flight lieutenant
Posts: 85
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Post by sdg111 on Sept 24, 2012 19:38:52 GMT 1
Thanks gents.
Fly, to be honest, I had paper, tape, a pen, all laid out to document how this came apart but it seems the ring bearing to the front of the housing has come apart, meaning a variety of ring shaped items came out of the housing. The one at the rear is still in situ. For £7 I'm going to replace the whole thing, and keep the spare housing in case the new one breaks. I'm hoping re-attaching the plastic mount to the motor is straightforward - I see there are two screws and two red washers, fingers crossed for that one!
For the record, I can't find clear instructions on how to change the motor mount anywhere.
Renard80, firewall seems okay. I've had a good pull at it and can't find any cracks at all. I'm away to look at your link, as from what I've read and heard from you guys, removing the firewall seems to be one of the most tricky things to do on the cub.
Thanks again.
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Post by flydiver on Sept 24, 2012 20:39:50 GMT 1
Reality - as I keep saying, there is a LOT of force on crashes. Physics says that's got to go somewhere. Metal bends, plastic breaks, foam crushes/bends/breaks. There are some tricks to strengthen things but sometimes this just makes the force go elsewhere and break something even more expensive or difficult to fix.
As you've seen, the instructions on the Cub suck. Almost ALL instructions on ALL planes mostly suck. In fact most of the instructions on every single piece of RC equipment are poor to miserable. Good instructions are rare, and excellent ones are astonishingly rare. There is seldom any help at all on repairs. That's what the RC community is all about.
A bashed plane is both a curse and a blessing. Once you've mentally 'discarded it' then you can approach it with little regret and see just what you can get away with. Over time as experience and confidence grows you will be amazed on what you can repair.
Having said that, gluing plastic motor mounts is an exercise in frustration. Gluing most hard shell plastic is not worth the grief.
Motor mount - carve it off as cleanly as you can. Replace using some kind of silicone caulk (bathroom stuff). Do NOT recommend either epoxy or CA for this. You'll regret it.
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sdg111
Flight lieutenant
Posts: 85
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Post by sdg111 on Sept 24, 2012 21:47:33 GMT 1
Fly, when you say motor mount, from your description I thought the cream coloured thing stuck to the fuselage was the firewall. The black piece of plastic to which the motor attaches I've seen described as the motor mount or gearbox assembly.
I'm confused - maybe I've got my terminology all mixed up.....
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sdg111
Flight lieutenant
Posts: 85
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Post by sdg111 on Sept 24, 2012 21:51:20 GMT 1
Fly, from your description of the motor mount, the cream coloured 'square' attached to the fuse- I thought that was the firewall.
The black piece of plastic to which the motor attaches I've seen described as the motor mount or the gearbx assembly.
I'm confused, I think I've got my terminology all mixed up..................
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Post by flydiver on Sept 24, 2012 22:04:26 GMT 1
Firewall is the foam bulkhead/fuse. The cream colored+angled thing is the motor mount. The black plastic is part of the gearbox. In this case the GB+motor are all part of the power package, that is, the motor. If you look at brushless mods one of the creative issues is to come up with a mount for the wide range of motors available. This is common enough there is now a market for it. www.headsuprc.com/servlet/the-1669/Motor-Mount-for-HZ/Detail. BTW- are you sure the motor + ESC are still OK? Folks frequently burn out the ESC by not cutting throttle INSTANTLY upon crashing and the prop being stopped. Replacing the proprietary ESC is often the breaking point in going brushless. It's stupidly expensive for a crummy bit of electronics. |
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Post by luvofthagame on Sept 24, 2012 22:10:44 GMT 1
...He meant firewall...and yes, there should only be 2 thick metal spacers...one for front and one for back...then you have the plastic spacer and nut for back of prop...then nut and washer for the front, that should be it...id be interested in seeing a pic as well as I'm curious why more parts came falling out cuz that can't be good...
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Post by luvofthagame on Sept 24, 2012 22:27:55 GMT 1
Kind of splitting hairs here, but its good to have the correct terminology to avoid confusion...the off white color plastic piece that is glued to the foam is the firewall...how do I know?...I have one new in pack that says firewall, so I cheated,lol...the motor mount/gearbox assemby is the same thing, they are just molded together...the motor mount is where the motor itself is mounted by the 2 screws with red washers...not trying to step on any toes, I just want to make sure we don't confuse anyone...
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Post by renard80 on Sept 24, 2012 23:28:05 GMT 1
Firewall is the foam bulkhead/fuse. The cream colored+angled thing is the motor mount. I'm afraid you're mistaken, fly! Sorry, but that 'cream coloured+angled thing' is NOT the motor mount. It IS the firewall. It's Part # is HBZ7114 - "Firewall with Screws". It is engraved in my mind, as I have had to buy so many in the past . . .  www.wonderlandmodels.com/products/hobbyzone-super-cub-firewall-with-screws/ |
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