Technical tips

[Mercuriell]

Started a sticky thread for your technical operational and build tips learned on the job

Replacing the main grip bearings - wmv 88MB

Setting up the cyberhead

Pinion and main block alignment

Removal servo CNC arms

Fitting 4525 motor to the Faifa







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Had to replace the crown bevel gear and had a hell of a job getting the mast out from the main gear assembly - had to take the rotor head off - put a 3mm rod through the jesus bolt hole and hammer it upwards

The cause of the sticking was some burring of the crown gear hub which I Dremel'd smooth with a 10mm fine grain cylindrical stone. SO the moral of the tale is make sure on assembly that the mast slides super smooth through the main gear hub while assembling to save yourself PIA later !

BTW the Kasama crown bevel gear is not quite the exact same size as the MA - bit frustrating as I have loads of those - it is a bit deeper but could be made to fit if the pinion gearbox is raised a bit more by ovaling the frame holes a bit more

[John Cook]

Head setup tips
I have a Kasama head on my Rex700 and combined with other things I've learned I'll give something a go.

doh goofed up
need to redo and add later :/

[Mercuriell]

Got round to enlargening the tank cut-outs yesterday - took ~3.5mm off bottom and rear edges (ie 1.7mm per side) - tank certainly felt nice sliding fit after and will test fly this afternoon see if it has cured the foam boiling

[Mercuriell]

Tank cut out certainly fixes the foaming - in any position !!!

[speedys4]

Originally Posted by Mercuriell

Tank cut out certainly fixes the foaming - in any position !!!

Did you cut the tank's mounting rubber at all? After taking about 1-2mm out the frame I have gaps in the corner between the rubber mount and the frame

[Mercuriell]

Originally Posted by speedys4

Did you cut the tank's mounting rubber at all? After taking about 1-2mm out the frame I have gaps in the corner between the rubber mount and the frame

No - it stretches out to fill on the gaps once the tank is put in - I know some people have cut them and left a small gap but I didn't see the need

[dankreed]

first all the picture i have isnt from my heli .. i just grabbed it cause i didnt have a picture of this part of my heli..

i have read in various forums about this teflon tube that is placed on the longer of the two tail control rods and that it is hard to get on and then doesnt stay in place.. so id like to share with you how i did it and it worked pretty good and was EASY to do..

first slide the teflon tube onto the rod before you put the link on.. to make this tube slide easily .. i just dabbed a bit of warm lightly soaped water in the tube and on the rod.. slipped right on.. with no problems..

i have been reading that people are have issues with the tube not staying in place.. i dont have a link but i did read an email response about this issue from kasama to a consumer..

simply it stated to not use CA or glue on this tube..

so i figured its approximate location.. grabbed a hair dryer turned it on high and within a couple of mins the tube had shrunk nicely around the rod .. its not going anywhere nice thing is it kinda of melds into the same color as the rod as it adheres to it.. so when done you can hardly see it.. i am not sure if you need to pay close attention to how long you hold heat on this tube.. i would imagine there is a point when the heat overwhelms and does some damage to the tube.. i didnt not have this problem

[TmMugen]

I think it is mentioned when I build this. MA had got this stuff too. Heat Shrink will do the job.

[Laurens]

Which crowngear is cheaper?

[nyc863]

My tips, I've finished the body of a FBL srimok, with electrics, and tail, but not done the boom yet.

nothing special and some duplicated.

1. if you are going to use the governor sensor arm above the clutch bell, then mount the sensor on it before you place it inside the frame and do everything up. You can get it out without busting back open the sandwich, but it is a pain..

2. bolt the header (Kasama or Hatori) onto the engine right at the start, and seal appropriately. I used arctic silver heat sink adhesive. Hope it works.. anyway, this is because you'll have to cut that fan shroud, so the sooner the better.

3. Keep a list of bolts you don't want to loc-tite yet, there are a number that you'll be taking on and off..

4. The tank is a bugger to get into the frame after the rubber gaskets are on, as they must be. As per the build videos, take off the cap so it is more squashable and use muscle. Its super tight. I don't know why it must be so tight especially if it is pressurized anyway.

5. Seat the crown gear into the main gear fully. Mine appeared to jam before it went in all the way and had not exposed fully the holes that the locking pin will go through (two of them anyway). Working away at it with my fingers failed, so I had to use leverage: allen key through the locking pin hole, and against the main gear metal, and force. I think a rubber mallet would be useful at least for me! If it doesn't seat all the way the locking pin won't go through cleanly.

6. Cyber head: grind down one end of the blade grip spindle until slop is gone. Use the bottom of the four hole choices in the head, that can get you 90 degree arms everywhere. Ignore the recommended linkage measurements for the top section of the head, I don't think they work. The servo to swash linkages are ok though.

7. Tail build is a bit like a chinese puzzle box, everything is right there on one page, but you do have to concentrate! It is actually fun, if you have time, and annoying if you don't.

8. Clunk line needs to be shorter than the manual says, otherwise it doesn't seem to flop around as well. But I guess lubricated by fuel and vibrated is a more forgiving environment than turning a dry empty tank around slowly by hand.

9. This probably applies to all nitro engines but bolting the muffler to the header is a pain! there are these weird nuts that you need to hold in place with right-angle needle nose pliers. And a ball-ended allen driver helps as well. Maybe I'm missing an easier way.

10. Those kasama patented link turnbuckles can be a headache. For your sanity, install all your links with the turnbuckle mark pointing the same way so that "clockwise" does the same thing to all links. They actually don't work too well for in-situ adjustments if you turn them with the included spanner the ball ends can pop off. And after an adjustment in-situ, ball ends will be at opposite extremes of position instead of in the middle of the ball at both ends (for links involving a twist in direction). The plus is that they offer infinite link sizing, not a minimum resolution of one full turn.

11. the vbar setup was pretty easy in the end, if you've done one before. Nothing unusual although "cylic gain" (the vbar word for aileron and elevator max pitch) is quite a bit lower than most FBL setups. With the default of 100+, max aileron or elevator gives way too much pitch, so it needs to be turned right down to get +10/-10 cyclic. The FBL head meanwhile supports crazy +/- collective pitch before virtual "cyclic ring" is needed, let alone you top or bottom out the swash..

[MaSt0RaS]

NYC can you show a photo where to put arctic silver?
i dont know from 90s... and i am waiting for it...

[nyc863]

Originally Posted by MaSt0RaS

NYC can you show a photo where to put arctic silver?
i dont know from 90s... and i am waiting for it...

it isn't normal arctic silver heat sink compound it is their heatsink glue that is like epoxy.. you have to mix it. i used it between the header, and the engine exhaust port in the hope that it will seal, is temp resistant, and bonds metal.
If you buy a hatori pipe it comes with a header and instructions but there is no gasket for YS, they said just use a sealant.. I believe for OS, they give you a gasket. If you compare the header you get with a Kasama header, the Kasama one more accurately matches the engine exhaust port but the difference is slight.

[TmMugen]

My first contribution to HF after getting booted out from RR. Apologise if this had been said. This is my take after srimoking for a while.

For the gearing, main gear and crown. After the first flight, you need to re-adjust these thing.

Main gear: undo engine sliding base screw and starter block screw also damper. And remove the engine back then slowly slide it in on the bottom engine leg corner should be nearly match to the engine base and slowly drive the bottom screw in, then push starter block in toward the gear and test it by turning the gear, it should be smooth as silk, if not you might go to far. When you get the gear matching perfect it shouldn't play at all, but it will roll smooth.

This thing will take time, as I never get it perfect in the first time to, I done mine about 4 time, to get it perfect match. Be patient and it will pay off. .

Now crown gear. After you got first flight, you need to check by looking true the main gear arount the back of main shaft ,then you will see the gear match with the bevel gear. Turn the gear till you can see the gear matching at center, you will only expect to see 0.5mm space between the crown gear and bevel gear and it should roll smooth too with no noise when you test by spin the blade. If you see it to far apart, all you need to to only undo the nut and turn the adjustable nut to get it 0.5mm. Then you will have perfect gear match.

To conclude: Basically, you have to readjust the pinion gear and main gear after the first flight, it OK to have some sound but when you rolling main gear you will not find any grinding, it will be like the gear can keep rolling forever. It's difficult to explain here. I find that the old paper trick to srimok gear does not work that well.

[MaSt0RaS]

Originally Posted by nyc863

it isn't normal arctic silver heat sink compound it is their heatsink glue that is like epoxy.. you have to mix it. i used it between the header, and the engine exhaust port in the hope that it will seal, is temp resistant, and bonds metal.
If you buy a hatori pipe it comes with a header and instructions but there is no gasket for YS, they said just use a sealant.. I believe for OS, they give you a gasket. If you compare the header you get with a Kasama header, the Kasama one more accurately matches the engine exhaust port but the difference is slight.

yeap i bought the kasama header... what you think toput a sealant or not...
i have this one Arctic Silver Thermal Adhesive 2 Part (Epoxy)
i think its ok.. but tell me if there a need to put it...

Also to put red loc or not?!

[Asid]

Hi

Many people have good results by using nothing between engine and header. Re-tighten after first flight while the engine is warm. This works well if both surfaces are machined flat.

I use epoxy on my 50 with excellent results.

Hope this helps

[MaSt0RaS]

Originally Posted by Asid

Hi

Many people have good results by using nothing between engine and header. Re-tighten after first flight while the engine is warm. This works well if both surfaces are machined flat.

I use epoxy on my 50 with excellent results.

Hope this helps

Yeap pls tell me and the other what you are doing i cannot take a decision..!

[garby]

Hi all i had fuel foaming on my first flight, i just swapped out the tank rubbers for the trex 700 ones, job done. No need to start hacking away at your frames.

The Crown gear on the MA and Kasama are the same size and the same number of teeth (70), however the recess in which the crown gear hub sits is deeper on the MA gear, there for when you go to put it back into the heli you will find that the holes in the mast and gear hub don’t line up. i had to put washers between the gear and hub to get it to sit correctly

[Asid]

SRIMOK 90N 2010 version are improved follow the list below:

1. KSM10-T09 Tail boom support Drive: Make more thickness on top.
2. KSM10-C01 Swash plate : Change material from 6061 to 7075 at Swash plate base.
3. KSM10-C01 Swash plate :Change Spherical bearing from IKO to ELGES.
4. KSM10-F17 Engine Damper support: Change to KSM10-F31 Adjustable engine mount.
5. KSM10-T18 Service cap tail gear box: Make bigger hexagon.
6. KSM20-TS04 Hexagon start coupling: Change to KSM20-TS10 Starter coupling (Hexagon joint).
7. KSM20-TS06 Starter shaft(OS): Change to KSM20-TS11 Starter shaft OS (Hexagon head).
8. KSM20-TS07 Starter shaft (YS): Change to KSM20-TS12 Starter shaft YS (Hexagon head).
9. KSM10-90H02 Main rotor grips (3mm): Change to KSM10-90H08 Main rotor grips set 4mm screw lock
10. KSM10-90H02 Arm grip (3mm):Change to KSM10-90H09 Arm grips blade 4mm screw lock
11. Throttle control rod 50mm (share with KSM20-C09):Change to KSM20-C10 Throttle control rod 60mm.

Source: sorry cant remember

[Mercuriell]

Had a lucky escape on the weekend - tracking was way out and on landing found that I had lost one SeeSaw pivot bolt and the other was loose - cleaned it allo up and red Loctited the bolts back in (x2 M3x7mm Srimok) - there's not much meat for the screw to hold onto in the seesaw hence using red threadlock this time.

Also took the opportunity to overhaul the head - found the steel former for the o-rings was rusting slightly on the spindle making it hard to remove so a maintenace item here would be a few drops of oil between the rotor head and blade grip regularly - changed the o-rings - they were dry but not too worn - the new ones seemed harder (80d on the packet) and boy they livened up the cyclic - bit too much for me - had to tone down the swash and put some expo in.

[Mercuriell]

The long Srimok arms mean a lot of load on the cyclic servos - esp when FBL so with current hungry servos like JR or Savvox make sure you have a really beefy power supply if you intend to do hard 3D - not an issue with sport flying and probably not with lower current draw such as BLS servos but I have had 4 power fades and 2 crashes now with my Faifa which I've put tracked down top servo/PSU issues.l