Trex 700 3rd Main bearing etc

[barney]

[barney]

The piccy in above post is of the QUK sceado lower brg block. It 10mm internal me thinks. Trex 500 Mainshaft is 8mm..just measured it.

The shape of the brg block is right for clearance but possibly only if the bearing is the smaller 8mm Item to match a trex 500 Shaft. Not sure how wide this block is.

My 700 is 60.5mm between the frames. It varies a little depending where you measure it

[electricsceadu]

the 700 frame is 60mm wide and the bearing block is also 60mm
what i didn't know was that the 500 mainshaft was 8mm (so used to 10mm shafts these days)
the bearing is 10mm id
the bearing size doesn't matter for myself as i can turn a 10mm shaft down to 8mm at the end on my lathe
for others you will need a new bearing with an 8mm id, not to much of a problem all you need to do is get an 8x19x6 bearing (at midland helis £2.45)
the original bearing size is 10x19x5 but with an 8mm id the only listed width is 6mm
if you want a plastic bearing block the hirobo part number is 0412-204
if you want a metal one get a quick uk block as it's half the price of the hirobo one

[barney]

Just so folk are clear on what we are trying to do.

The 8mm Trex 500 mainshaft (cut shaft) is pushed internally into the Trex 700 mainshaft and secured via the Jesus bolt through both shafts.

This then extends the originial Trex 700's shaft below the main gear. In standard form it does not extend low enough for a 3rd bearing, hence the 8mm internal bearing to match up with the Trex 500's shaft..

Yes a 8x19x6 may be an option for the bearing but The problem (possibly) with the current sceadu block is it MAY possibly still hit the fan due to the external dia being larger than necessary. (see raptorheli2's picture above of the 700 brg block)

We are defo getting there folk..

[raptorheli2]

the only slight concern i have is do we trust the ID of the main mast enough to insert a trex 500 main mast into? remember this must be a very good fit or we might get bad vibrations through it.

i think that sceadu block looks ideal, keep us posted how it works and i'll order a couple.

cheers

[electricsceadu]

my blocks on its way
i haven't the time at the moment to look into fitting it but i should be able to find some time next week so i'll let you know how it goes

[electricsceadu]

sceadu 3rd bearing block on the 700

i've managed to find some time to fit the sceadu bearing block, i used the 8mm id bearing and a bit of an old shuttle mainshaft
heres some pics with it fitted without the main gear in place

[raptorheli2]

great work, but the pics are not the best so can't really see how much clearance you have ended up with.

did you need to modify the fan shroud or anything? also does the main gear fit in ok, i.e it doesn't rub on the new block?

lastly...nice work.

cheers

[Made2Fade]

Intrested very much in this... can you get some better pics for us?

Cheers
Lee

[electricsceadu]

i'm going to try to get some better pictures in the day light

no mods to the fan, the main gear fits as std
the new block sits lower than the main gear so no clearance problem

what i did find was my main gear was about to fail and it looks like the main gear and pinion are not running parallel to each other
as i've just fitted the metal clutch bearing block as well tonight i filed away some of the lug to make the mesh adjustable, i'm no longer using the sholdered bolts or the stepped washers that you can get , i have just used the quick uk socket screw finishing caps on the bolts for the clutch bearing block and the engine mount so i can slide the block and engine to get the mesh correct and keep the engine in line
i'm taking it out tomorrow so i'll find out if it works ok

[Made2Fade]

i'm going to try to get some better pictures in the day light

no mods to the fan, the main gear fits as std
the new block sits lower than the main gear so no clearance problem

what i did find was my main gear was about to fail and it looks like the main gear and pinion are not running parallel to each other
as i've just fitted the metal clutch bearing block as well tonight i filed away some of the lug to make the mesh adjustable, i'm no longer using the sholdered bolts or the stepped washers that you can get , i have just used the quick uk socket screw finishing caps on the bolts for the clutch bearing block and the engine mount so i can slide the block and engine to get the mesh correct and keep the engine in line
i'm taking it out tomorrow so i'll find out if it works ok

Kool... keep us informed please... better pics will be great

Cheers
Lee

[electricsceadu]

i flew the 700 today, i only got 1 gallon of fuel through it but so far its holding out ok
a also had a couple of flights with my freya and raptor 90
hopefuly the pictures turn out better than the last ones

[electricsceadu]

and the last two pictures

[raptorheli2]

top marks, i'm going to order now.

p.s what size bolts does it take? m3x10mm?

cheers

[electricsceadu]

the 8mm shaft into the mainshaft is 30mm long and the bearing block bolt centres are 6mm from the frame above them
if you wanted you could line them up with the fan case bolt so it doesn't look a little odd with the bolts at slightly different heights
and the 8mm shaft goes all the way through the bearing with a little sticking out
and if you use an 8mm mainshaft for the shaft you will need to drill out the bolt hole to 4mm