Resurrecting a Legend: JR SG E12 ITO

[mverhorst]

Originally Posted by DCflyer

The nick maxwell edition is a 4235 stator. Same motor essentially as the 4525 - just different dimensions. Either will work perfectly.

DCFlyer,

May I ask how the freewheeling on your oneway feels?

Is there quite some drag or will the gear just keep spinning you give it a push?

And if you turn the head in the correct direction by hand, does your motor spin also?

Thank you,

Menno

[DCflyer]

Originally Posted by mverhorst

DCFlyer,

May I ask how the freewheeling on your oneway feels?

Is there quite some drag or will the gear just keep spinning you give it a push?

And if you turn the head in the correct direction by hand, does your motor spin also?

Thank you,

Menno

Sounds like your one way bearing is locking up. The head should spin very freely if you give it a push and no - it should not be turning the main gear/motor or you wouldn't be able to autorotate.

You can try breaking the bearing free by holding the main gear in one hand and turning the head with the other. It might break free, but will probably lock again during flight if its in bad shape.

In that case you'll need to remove the main gear assembly from the machine and inspect your one way bearing inside. Make sure all the teeth are there and nothing is really loose etc. It might just need the old grease cleaned out of it. Also, don't use heavy grease on these. I use a coat of Tri-flow oil which is a very light oil. The grease can tend to gunk up and cause it to lock like you're seeing.

Worst case you might have to replace the one way bearing inside which will require you to use a press and press it out and install a new one.

[mverhorst]

Originally Posted by DCflyer

Sounds like your one way bearing is locking up. The head should spin very freely if you give it a push and no - it should not be turning the main gear/motor or you wouldn't be able to autorotate.

You can try breaking the bearing free by holding the main gear in one hand and turning the head with the other. It might break free, but will probably lock again during flight if its in bad shape.

In that case you'll need to remove the main gear assembly from the machine and inspect your one way bearing inside. Make sure all the teeth are there and nothing is really loose etc. It might just need the old grease cleaned out of it. Also, don't use heavy grease on these. I use a coat of Tri-flow oil which is a very light oil. The grease can tend to gunk up and cause it to lock like you're seeing.

Worst case you might have to replace the one way bearing inside which will require you to use a press and press it out and install a new one.

Thanks for getting back to me...

This is on a new build...

I have a thread going in the Forza 700 section.

https://www.helifreak.com/showthread.php?t=725475

Now I am not sure again what to think of it... haven't installed the gear assembly in the heli yet...

[DCflyer]

Managed to finish the build this weekend. iKon is programmed - I have 3 banks of flight modes including a self-level. Only need to do final pitch setup on the head. Swash is leveled and tail is fully set up.

The head linkage setup turned out really well. The pictures don't really do it justice. Its huge and beefy and looks fantastic. Really happy with how it turned out. The Synergy links are an absolute PITA to get them to go onto the large 5mm Synergy balls. I had to get creative but finally got them on. I measured them 3 times before attaching them so I wouldn't have to take them off again. The entire head is now fully adjustable from the aileron bell-cranks to the blade grips.





Here is the battery harness setup - the previous owner had it set up like this and I really liked it. I made a new harness with fresh wires. Fresh EC5's on the entire machine/batteries etc.



The final improvement I made to this airframe is to the forward tail case assembly. There are 4 long bolts that pass through the tail blocks and are held on by locknuts on the other side. The problem is the bolts are too short - only a few millimeters stick out of the other side. As a result, the locknuts that are included in the kit are really small and rather pathetic. I really wasn't confident on hardware that small on a 700 size machine. I sourced some longer (and slightly thicker) shouldered bolts and had to cut them down to the right length with a dremmel. This allowed me to use nice big beefy locknuts on the other side in addition to some washers to distribute the load more evenly along the frame.



The tail assembly finished. I didn't do much to this section aside from add some spacers and washers to a few places like the rear boom supports and tail fin. I chose to discard the horizontal fin as i'm not a fan of it. I like my boom setup clean without it. I also ordered a Fusuno carbon boom support brace that should be here soon to help keep the struts nice and tight. Lastly, I decided to go with a set of Blade 700x tail blade bolts. They are a few grams heavier than your average bolts which helps alleviate the tennis raquet effect on the tail and helps the tail servo run cooler and pull less amps.






The final product:




I will do a final couple pictures when I get the blades,canopy,batteries on. Build went very smoothly - machine came together very well. Can't wait to get it in the air.

[malc1]

Nice job!

[cboo]

Your build looks great! Just to mention, I've had a couple of issues with my build so far. One of the holes of my T-arm assembly is not tapped correctly and m2 x 8 screw won't go in. Also, I didn't have to add any shims for the main gear assembly as you mentioned, but I did have to add a shim to the auto drive shaft along with the poly slider 0.13 that the kit comes with. It took me quite a while to figure out what was wrong, very frustrating. JR Americas doesn't have the T-Arm in stock and they are trying to locate one for me in Japan but its been a couple of weeks. I haven't been able to find a 2mm tap to fix the T-arm myself, not in the USA anyways. A company in China has one, but I guess I give JR Americas a little while longer to find the part.

[DCflyer]

Sorry to hear about that. Sounds like you just got a bum part. No big deal. I would avoid JR America's for out of stock parts. They are a great resource for things they have in stock. They order from RCjapan.net. I would just order it directly from them.

Search by the part number in your manual there but keep in mind their part numbers are laid out differently. They don't use the "JRP". They just go by actual numbers. Edit that out and you should be able to find it there.

If you can't find the part number let me know. I have a source for that as well.

[cboo]

Thanks again for your reply! Thank you for taking the time to post your build. You helped me out a lot being able to see what its suppose to look like. For instance mentioning where the main shaft collar goes. Looking at the diagram in the manual I would have been scratching my head. Plus seeing how you set up your wiring. I'll give JR America a couple more days, in the mean time I'll check RCJAPAN to see if they have the part.

[cboo]

I ordered the part from rcjapan as you mentioned. I just don't understand why a 700 class heli would use a 2mm phillips head screw to hold a ball link on. I think the last heli I used that size screw in was my CPMX.

[cboo]

DC Flyer, A couple more questions if you don't mind. The elevator servo I am using are the Xpert SI 4401. The width is 1.48 inches which is a little smaller then the JR 8717 that you are using. The fit is very tight due to the narrow frame and is actually pressed against the frame. I have tighten it as much as I think I should, trying not to deform the rubber isolators too much. Is your servo fitting that tight? Also the white servo arm circles that come with the kit don't fit on the XPert servos. I like the look of the red JR servo arms that you are using. Do you know if they would fit the XPerts, is the opening adjustable? By the way, I'm still waiting on the T arm leveler from Japan, I hope it didn't get lost in the mail.

[malc1]

Originally Posted by DCflyer

Sure thing - here it is:

https://rcjapan.net/jr-heli-parts-61...56f962m32u15u5

These red alloy blocks have now arrived this morning from RCJapan.
Excellent quality as usual.
Everything now here to fully complete the model including JR XB710 -FBL main blades. Still busy with other things at the moment though.

[DCflyer]

Originally Posted by cboo

DC Flyer, A couple more questions if you don't mind. The elevator servo I am using are the Xpert SI 4401. The width is 1.48 inches which is a little smaller then the JR 8717 that you are using. The fit is very tight due to the narrow frame and is actually pressed against the frame. I have tighten it as much as I think I should, trying not to deform the rubber isolators too much. Is your servo fitting that tight? Also the white servo arm circles that come with the kit don't fit on the XPert servos. I like the look of the red JR servo arms that you are using. Do you know if they would fit the XPerts, is the opening adjustable? By the way, I'm still waiting on the T arm leveler from Japan, I hope it didn't get lost in the mail.

I'm not exactly sure what you're experiencing in terms of servo fitment. A picture would help a lot here since that is hard to visualize.

Do you mean the back of the servo case is touching the opposite side of the frame? If so, you simply need to space the servo out a couple mm's. Just use a metal/carbon servo spacer to move the servos outward a bit. I've done that on a couple models now.

Those Xpert servos look really good - brushless. Nice. They won't accept JR style servo horns because the Xpert servos are a 25T spline output shaft aka "futaba style". 95% of servos use a 25T. JR uses their own 24T spline setup on their servos so they include 24T servo horns in their kits.

You will need to source some 25T servo horns for your servos. The horns i'm using are made by JR for JR servos so they won't fit.

I would look at Seacraft horns. Very nice units. Just make sure you buy the right length. Cyclic servos need 17-19mm units and your tail servo needs a 15-17mm version. Futaba style. They will be red.

I have a picture of one on my tail servo further up on this page. Do note - these horns fit VERY VERY tight. They are press fit - you will only be able to get them started by hand and will have to use the servo horn screw to get them the rest of the way on. So make sure you are putting it on correctly when doing servo setup. Seacraft sell a servo horn removal tool for when you need to take them off. Its like $5 - you will need this if you ever want to get them off trust me.

[cboo]

Yes, the back of the elevator servo case is touching the opposite side of the frame. I can see how I could move the pitch servo out using a carbon spacer but the elevator servo mounts inside the frame unlike the pitch servo. The only way I can see to move it away from rubbing against the opposite frame would be to squish the rubber isolators flat. My concern is, if the casing is against the opposite frame will this cause vibrations and affect the servo function.
Thank you for the information explaining the difference between the JR spline and most other servos. The seacraft servo horns look nice, something to consider.

[DCflyer]

Just to round out this build..........here it is with batteries and canopy on. With the CY Radix V2 710mm and 106mm out back mounted. It came out great - really quite a large machine. Should have good presence in the air. The drivetrain is so smooth - I can spin the head lightly and it will just sit there and rotate for 12-15 seconds. Also mounted the Fusuno carbon tail boom brace which tightened up the boom supports nicely. Good upgrade.

[trillian]

That is a very classy looking machine!

[DCflyer]

Originally Posted by trillian

That is a very classy looking machine!

Hey thanks. I'm very pleased with how it turned out. Can't wait to see what it'll do in the air - I expect it to be nothing short of a handful

[bathmagic]

I had one of these and sold it for a reason i cant recall

I truly wish i could get a kit now--awesome machine, I have searched everywhere but no one stocks it anymore.

[Cman]

Sweet looking heli
nice build thread

I look forward to seeing the video of the madian.

I need spring to come fast

[DCflyer]

Originally Posted by bathmagic

I had one of these and sold it for a reason i cant recall

I truly wish i could get a kit now--awesome machine, I have searched everywhere but no one stocks it anymore.

Yea the kits are getting pretty hard to find. Parts are still easy enough to locate. I would try to get a hold of a JR rep in your area if you're really wanting one. They might be able to track down a kit somewhere for you.

[DCflyer]

Originally Posted by Cman

Sweet looking heli
nice build thread

I look forward to seeing the video of the madian.

I need spring to come fast

I was going to maiden it last week but the weather got so cold I didn't want to risk it with the parts being more brittle. I'll wait until it warms up a bit, give her a few shakedown flights, and then start to flip it around. I'll try to get someone to video.