Buildthread: RJX Xtreme EP90

[Druekerfish]

Congratulations Garfield. We are on the proper way. It is good that we are on the same hopefully final problem. My Xtreme is taken apart on my desk trying to fix it after the lost tail pulley pin Hopefully RJX changes this old design, why not making it the same as the other pulley at the other side of the belt that has no pin? It has been minor damage, mainly the blades. I am having now little time for it, mainly checking the way to proceed.

After reading in the microbeast forum my conclusion is that this ship is lacking power in the tail at 1700 rpm. microbeast is not helping anyway. The solution could be

-more rpm, I really do not like, I prefer longer and smooth flights
-other tail servo
-longer tail blades give vibrations to the Xtreme
-other dampers, very hard the stock ones from the Xtreme
-try the microbeast DMA (parameter F) now set up to a medium value. If you are lucky and it is in the proper direction it helps. I do not think it will be the solution
-vstabi. I am about to swap it with my Logo, but I really would like to solve this problem.
-other?

My german is very basic, but I tried to post in a friend forum where the official pilots use to contribute: http://www.rc-heli.de/board/showthread.php?t=176798 Great, here comes the first suggestion: longer tail blades, but they give vibrations to the Xtreme

[garfield2412]

hi Carlos,
i just got a message from rc-heli.de *lol* i thought, maybee this guy is similar to druekerfish :-)
yes, it's you... !
your german is very good!

so ny thoughts about tail:

longer tb - i fly 105, not better at all.

more rpm - seems to be a good soloution, uwe caspart wrote about 1850 for good hs in a german forum. but he also does slow 3d with scorpion 5035. so hs won't be the main problem?

another tail servo: mhhhm expensive and savöx isn't bad

beastx-team suggests: tail-servo - move one hole more to center. but: i have setup 11.5, you have 13.5 and there is the same tail kick-out.

maybee some rjx-cracks like sebastian z. have a good idea. so lets wait for german-forum answers.

[garfield2412]

just some information:
CC answered my mails:
first mail about govener setup =
the 4035-500 is a 10 pole motor and needs to be run at 8 Khz PWM and low timing.... The GOV Gain will need to be at 7 for this motor. If you want to send your setup file by saving it in Castle Link and email me the file I would be glad to look at the other settings. Thanks very much. 3.26 firmware is working very well.

second mail about my CC-Setup:
Everything looks good you just need to set the current limiting to insensitive. Thanks for the follow up.

[garfield2412]

SUCCESS!!!
just tried 2 packs, no more tail wag with gov.gain "7", i'll attach my CC settings later. CC ICE HV is great, i love it, no need of an kontronik until now!

tail didn't held much better the first flight, but after the tail-wag was gone in case of the lower govener, i could increase my overall gyro-gain +3%.

second flight was just great. tail was 99% straight 90degrees, even at pitch pumps or tic-tocs (according to my skill, i think you can do it better :-) ). i think i can increase gyro gain 1-2% once more.
i'll have to try another FF-flight, if there is no crazy wag of death when increasing the gain once more.

BUILD IS DONE :-)
just my CC settings and my log from my 2 warm up flights this morning to share my experience:


################################################## #####
# Castle Link Data File
# Created: Saturday, February 19, 2011
# Do Not Edit This File By Hand
################################################## #####
Hex55: 85
Brake Strength: 0
Brake Delay: .6 sec (Delayed) (*)
Brake Ramp: Immediate (*)
Cutoff Type: Soft Cutoff
Motor Start Power: 59
Direction: Reverse
PWM Rate: 8 Khz
Current Limiting: Insensitive (180A)
Cutoff Voltage: Auto Li-Po (*)
Motor Timing: 5
Vehicle Type: Helicopter
Throttle Type: Governor Mode
Throttle Response: 5
Governor Gain: 7
Initial Spool-Up Rate: 5
Head Speed Change Rate: 5
Auto Rotate Enabled: False
Governor Mode Type: Fixed
Vehicle Setup - Battery Type: LiPo
Vehicle Setup - Number of Cells: 12
Vehicle Setup - Battery Voltage: 44.4000
Vehicle Setup - Gear Ratio: 10.000
Vehicle Setup - Motor Kv: 500
Vehicle Setup - Motor Number of Poles: 10
Desired Head Speed 1: 1501
Desired Head Speed 2: 1752
Desired Head Speed 3: 1899
Data Log Enabled: 255
Sample Frequency: 5 Sample / Sec (*)
Power-On Beep: Enabled (*)
Auto-Lipo Volts/Cell: 3.3 Volts/Cell

[garfield2412]

just tried 105mm edge tail-blades today.
tail is way better than with rjx blades. very stiff, precise tail, nearly no more kickouts at hard pitch inputs, only if you try hard pitch pumps (12-14deg) at 1500rpm :-)

[Ketnet]

Hi guys
i also have a Rjx 90 EP but TT version.
Thing is, my vertical tailfin realy shakes and vibrates like crazy. no wag, no kicks (BX)
I just left it that way.... and now!!! the bolts that hold the aft tailcase simply ripped the boom! I noticed this after i pulled it inverted and suddenly i heared things vibrating. and checked back home
So this fyi! do not fly if the tail fin shakes!

Could anybody confirm the fin vibes could come from the scorpion engine or the pinion bearing?
I just now noticed there were funkey 105mm tailblades on...

[garfield2412]

Originally Posted by Ketnet

Hi guys
i also have a Rjx 90 EP but TT version.
Thing is, my vertical tailfin realy shakes and vibrates like crazy. no wag, no kicks (BX)
I just left it that way.... and now!!! the bolts that hold the aft tailcase simply ripped the boom! I noticed this after i pulled it inverted and suddenly i heared things vibrating. and checked back home
So this fyi! do not fly if the tail fin shakes!

Could anybody confirm the fin vibes could come from the scorpion engine or the pinion bearing?
I just now noticed there were funkey 105mm tailblades on...

hi,

thats strange! i modified to TT 3 Months ago, no problems at all, even better than belt!
what HS do you run?
did you check the TT for smooth running? how many TT bearings did you install? i noticed Laurens installed 3 bearings in the boom, so i decided to do this too. check the bevel gears for propper operation and smooth running! p.s. LAURENS: your "old" TT-Tail runs very fine

motor must run smooth without preasure to any bearing or to gear. if everything runs smooth everything would be fine. if you are not sure about the condition of the bearings: change them!

any progress since you posted?

[Ketnet]

Hi
i just installed the new boom. i did notice the one i have now is a large outside diameter, as the tailrod holders really needed to be enlarged (they were on the last boom over some tape)

i have 2 bearings in the TT, headspeed 1920, scorpion with helical maingear but the previous owner decided to cut the pinion short so the motorshaft goes through adapted bearing. (jurrien Saelens, very good pilot)
Would it be dangerous to fly without the pinion support? (6mm shaft)

i still have to check if its still shaking (too busy with the kids +bad weather)
Changed the delrin bevels+tailshaft (had a very little play on the tailshaft with the slider)

[garfield2412]

hi,
i think i know every of Juriens youtube RJX90 videos i like his flight style very much! very smooth and precise.

but i don't know what you mean with "he cut down the pinion... "?
so is it right, that you fly without the bearing on the end of the pinion (pinion support)?
i don't think thats a good idea! once in a german forum Uwe Caspart (German Heli-expert and RJX Team Pilot) wrote about that bad idea to fly without pinion support, also with an 6mm shaft!
so i don't know what Jurien/you wanted to aim with this modification?

HS 1920 isn't a problem for TT... >HS 2200 might be a problem and you 'll get tail vibrations!
i flew HS 1975 last week with an borrowed Pyro 700-52 without problems. with my 4035-500 i fly thee same HS as you.

i think changing the bevels was a good idea.
another thought about the tail vibrations: did you check the taishaft if it's straight?

so i'm curios about your next "maiden" flight

Originally Posted by Ketnet

Hi
i just installed the new boom. i did notice the one i have now is a large outside diameter, as the tailrod holders really needed to be enlarged (they were on the last boom over some tape)

i have 2 bearings in the TT, headspeed 1920, scorpion with helical maingear but the previous owner decided to cut the pinion short so the motorshaft goes through adapted bearing. (jurrien Saelens, very good pilot)
Would it be dangerous to fly without the pinion support? (6mm shaft)

i still have to check if its still shaking (too busy with the kids +bad weather)
Changed the delrin bevels+tailshaft (had a very little play on the tailshaft with the slider)

[Ketnet]

mmm, i just checked the tail shaft, its bent a tiny tiny bit, but replaced it out of precaution as mentioned.

what he did to the pinion, is he shortened it so there is no smaller top (so the pinion stops with the gearing itself, not with a smaller part).
So instead of the smalller piece that normally goes into the counterbearing, its the motor shaft that goes through the counterbearing, but then off course you need a long shaft.)

edit: update: remaiden: less vibrations in the fin, but still there, you can still see the tip of the fin shaking at high high speed.
+Lowered the head speed 1% (seems better now)
+Test: renewed the motor bearings and tested without the counterbearing result: same, still shaky, but maybe bit less.
+Then, other 105mm blades (TIG) dude! when at speed, a crazy sound from the tailblades like a horse that blows his xl lips... so sucky blades, dustbin..
+Then, put the funkey tailblades 105 back on: less shaking in the fin
What i did notice, is that the screw that hold the scorpion are maybe like only 0.8cm long in the engine itself?? maybe this gives very little play for the engine?
i'll see if i can get another engine to check ...
relubed the tailbearings...were a bit dry ;-)
New head bearings and dampeners are on the way,
so... uptil now, really minimal vibrations but they are still there. i'll keep my eye on it and evaluate..

[garfield2412]

the idea and modification from Jurien sounds good! but you need a long shaft motor for this mod.
maybee it's way better than to glue the pinion into the bearing.

congrats to your "maiden". check every part of the tail and maybee the TT.

[Ketnet]

Yips

I'll be putting in the 700M engine from a friend of mine. (didnt, work, does not fit... )
I flew the beast yesterday on the clubs bbq, dude, the rjx still is a mega beast!
Glad to have it ;-)

[billiano]

Another ''little trick'' from Laurens on page 1 is that he used Kasama swashdrive arms.