N5 - A mods/tips thread!

[Britflyer]

I think everybody has covered most of the points, good and not so good, on the N5 so I won't repeat, but here are a couple of mods/ideas that maybe of use to peoples. 1st one I posted in another thread but repeated here.

1) Firstly If you want to speed the cyclics up (without reducing the stability by moving the balls on the bell/hiller mixing arms on the grips) just replace the two short balls on the the inner ring of the swashplate that you connect the long pitch links too with the longer balls (same P/N as the 3 used on the outer ring of the swash)

This will give you more direct cyclic input into the blade without reducing stability!! Win Win.

The swashplate is IMO quite a low ratio design and easily allows this little mod to work. Being low ratio will make it good for flybarless conversions too, by putting the short balls back on!

BTW, I have actually done this mod (see pic below) and like it. An easy fix for those that want that extra bit of cyclic but not wanting to compromise the stability of the heli!!


2) If like me you are a fan of the CSM 720 but wondering how best to mount it. Here is how I did it (see pictures to save me describing it). Two carbon plates and the plastic mount is a Compass Gyro plate > http://www.evorc.com/product.php/97/...-mount-plastic

I found the N9 rear gyro mount didn't fit the frames to well so used this method. This method also keeps the gyro below the canopy line so looks cleaner IMO.

Obviously need to keep an eye on the gyro mounting pad due to fuel ingress, but a small price to pay IMO.

I used the same method on my N9s and it works very well. In fact both the N9 and now the N5 seem to be the best models I have mounted my 720s in, in terms of gyro performance/vibration levels

Abit of work I know but worth it to get the 720 mounted well!!


Cheers

Paul

[Britflyer]

2nd post - will be filled with all the other mods/tips from other threads, to keep in one place and are pretty much just cut and pasted. So sometimes the context might not be immediately obvious but I will try to make sure the tip/mod makes sense in this post.

NOTE: Not all these tips may not be applicable, as tolerances do vary from kit to kit. And laterly the kit may get updated to correct some of the issues.

I've also tried to give the credit for the tip/mod at the end of each one. If I have this wrong PM me.

Lots more tips can be found at http://mattbotos.com/

************************************ Check you mainshaft collar ************************************

As I was working on one of my N5's today, I remembered something critical I saw during the pre production build. One of my split collars was tapped on both sides, this is not correct! The split collar should be tapped on one side and a through hole on the other side, otherwise the split collar will not clamp the main shaft all of the way. With both sides tapped your screw will basically bottom out without adequate clamping.
The factory was notified but this does not mean that a few collars escaped through Q/A.
Everyone should check their split collars to make sure the bore side is a through hole. If it is not, use a 2.5mm drill bit and carefully drill the side of the split collar which has clearance for the head of the bolt.

My apologies for not remembering this earlier.

Matt Botos

************************************************** ************************************************

3) The bolt that holds the tail idler pulley on the tail box should be sufficiently loose for you to be able to turn it by hand. (synergyn9 + Matt Botos)

4) There should be no up and down play/movement on the main tail pulley on the main shaft. Tail pulley is split to allow the jesus bolt to be cranked as tightly as possible. Mine was tight but allowed some 1mm movement. Even now once as tight as I can get it there is still slight movement. Maybe a tolerance issue? If the pulley is not tight, Matt believes the rocking can lead to harmonics situation where by it gets to the point that the tail belt can actually get nipped and lock the tail, leading to failure. (synergyn9 + Matt Botos)

5) Red or green locktite maybe required between the tail output shaft to the flange bearings as the shaft seemed to be undersized by 0.05mm causing a tiny amount of rocking. When doing this make sure there is no tension on the belt while the loctite drys (JamieM)

6) Potential play/movement developing between the G10 plates on the tail gearbox and the two flanged bearings can be mitigated by pressing out the beaings and re-fitting with abit of epoxy/CA. Be careful not to get any epoxy on the bearings! (Mattie-lodge)

7) Although not shown in the manual the boom support ends can be pinned in place quite easily, as per the N9. There are two holes either side of the boom support ends, once the glue has dried, drill through one of these holes thru the otherside with a 2.5mm drill. Then take some M3 bolts and screw them thru the drilled hole! The ends definately won't come loose now! (Britflyer)

8) The supplied bolts for the tail blades are threaded all the way across. These wore deep into the brass insert on the tail blades and caused quite alot of vibration on my tail. I had to buy some m3 x 30mm bolts which had a 10mm long smooth shank and put a 1mm washer under the head. Put the nut all the way on the other side and dremmel'd to length. Been perfect now. (Grant_beltcp)

9) Secondly, the tail grips appear to be machined slightly wider than normal. To tighten the tail blades it bent the grips in very slightly meaning only the very tips of the blade grips actually clamped the blade. After a few flights this began to damage the tail blades and got alot of sideways flex. I had to add 2 x 15 thou shims. One on each side took the slop out perfectly and not had a problem since. This may vary with different make blades, I was using align blades. (Grant_beltcp)

10) The standard tail slider locking washer that comes with the kit (Both N5/N9) are not brilliant and therefore you have to epoxy/CA it once it is fitted to stop it coming off. What i have done on both my N9/N5 is change the locking washer for a better quality one. The replacement star locking washers i have used have a wider contact point on the locking pins so the washer has much more force on them so it is actually doing what it is supposed to do and dig into the brass bushing and the more it is forced to come off the more it digs in. (ROSSCO)
You can get them from any fixing suppliers or from the following online store:
Starlock Washers 718

11) Locking of the auto rotation one way bearing.. remove all grease by spraying with wd40 and rotating bearing till clean.
Dry with clean lint free cloth.
Replace with a few drops of light oil such as 3 in one - or ATF (auto trans fluid)
Check size of outside diameter of auto rotation sleeve, should be 11.98mm have found some are 12.04mm.
Use fine wet and dry with a little oil in the area where the bearing runs, sand till the right size, turn sleeve as working paper back and forth.. Can be bolted onto a main shaft..for easy of holding.. (rspblake)

12) Leaky Tank ?? If you have a issue with the fuel tank leaking at the rubber grommet! The opening in the tank is possibly 14mm, instead of the 13mm, it was supposed to be. There was a few that escaped the factory that way. Matt Botos suggested putting a couple O rings on the grommet. (rspblake)



Paul

[Grant_beltcp]

Another one for the tail... I've been using Align tails so may differ with other blades.

1) The supplied bolts for the tail blades are threaded all the way across. These wore deep into the brass insert on the tail blades and caused quite alot of vibration on my tail. I had to buy some m3 x 30mm bolts which had a 10mm long smooth shank and put a 1mm washer under the head. Put the nut all the way on the other side and dremmel'd to length. Been perfect now.

2) Secondly, the tail grips appear to be machined slightly wider than normal. To tighten the tail blades it bent the grips in very slightly meaning only the very tips of the blade grips actually clamped the blade. After a few flights this began to damage the tail blades and got alot of sideways flex. I had to add 2 x 15 thou shims. One on each side took the slop out perfectly and not had a problem since. This may vary with different make blades, I was using align blades.

Tails very good now.

[Britflyer]

Thanks Grant, i've added those to the first list. Did you use pre-made shims that can be bought or did you make them for the tail blade grip spacers?


Paul

[Grant_beltcp]

Ales Hasell gave them to me at weston park, but I belive they came with an old set of radix tail blades. I'll point Alex to this thread and he will be able to say.

[mark Taylor]

Just curious as to why You gone to all the trouble of fitting the 720 gyro at the back Paul ??
When there's sufficient room under the canopy upfront.

[ROSSCO]

I have not done many modifications to the build of my N5 but what i have done is change the tail slider lock washer as i did on my N9, also added bolts to the boom support ends as on the N9.

The standard locking washer that comes with the kit (Both N5/N9) are not brilliant and therefore you have to epoxy/CA it once it is fitted to stop it coming off. What i have done on both my N9/N5 is change the locking washer for a better quality one. The replacement star locking washers i have used have a wider contact point on the locking pins so the washer has much more force on them so it is actually doing what it is supposed to do and dig into the brass bushing and the more it is forced to come off the more it digs in.

This is the type of (8mm) Star-Locking Washer i have been using:


You can get them from any fixing suppliers or from the following online store:
Starlock Washers 718

[Britflyer]

Just curious as to why You gone to all the trouble of fitting the 720 gyro at the back Paul ??
When there's sufficient room under the canopy upfront.

Because over the last 11 years of flying helis my gyros have always worked best mounted away from the engine, and that means at the rear for 99% of helis.

It wasn't that much trouble as the plates were CNC cut and I made them over 2years ago, so only two holes needed drilling to fit to the N5.

I am sure the 720 would work at the front ok, but experience tells me mounting at the rear will be better than just ok!!

Cheers

Paul

[raptorheli2]

fwiw the gyro doesn't work well upfront on my N5. out back is defo the place for it.

i also think they work better at the back away from the vibes.

cheers

[mattie-lodge]

Mine also works better out the back. I found with the gyro up the front the tail felt a little loose. With the gyro mounted up the back it improved no end.

I've got to say though I didn't play with gyro mounting which probably
would have improved it

[Britflyer]

Matt,

Which skid pipes did you use with the Align cross-struts?


Paul

[rspblake]

Locking of the auto rotation one way bearing.. remove all grease by spraying with wd40 and rotating bearing till clean.

Dry with clean lint free cloth.

Replace with a few drops of light oil such as 3 in one - or ATF (auto trans fluid)

Check size of outside diameter of auto rotation sleeve, should be 11.98mm have found some are 12.04mm.

Use fine wet and dry with a little oil in the area where the bearing runs, sand till the right size, turn sleeve as working paper back and forth.. Can be bolted onto a main shaft..for easy of holding..

gyro mounts if wanted I have a few here..

Evolution RC,Rockamp,Kokam,Align,Beam,Rave,Wera,Synergy,ElyQ ,Scorpion,Rapicon,Spartan> Home > Rc Helicopter Spares > Compass Model > ALL COMPASS SPARES > 02-1843 Gyro Mount Plastic

[Britflyer]

I did Grants tip on the plain shank tail blade bolt tonight as I could see brass in the threads of the bolts after only 6-7 flights!

Also shimmed the tail blades too, a proper fit now.


Paul

[mattie-lodge]

Matt,

Which skid pipes did you use with the Align cross-struts?


Paul

I just used the standard Align ones Paul.

[rspblake]

If you have a issue with the fuel tank leaking at the rubber grommet!

The opening in the tank is possibly 14mm, instead of the 13mm, it was supposed to be.

There was a few that escaped the factory that way.

Matt suggested putting a couple O rings on the grommet.

This solved the problem.