Buildthread: RJX Xtreme EP90

[Druekerfish]

Just a few more experiences. The heli is flying OK but it has been for me difficult to tweak. My current config is:

-Xtreme 90
-Scorpion 4035 400
-Align servos
-EDGE 690 blades
-10th pinion and 93 MG
-15 mm tail servo arm
-95 mm tail blades
-microbeast

I get 1800 rpm with the Jive at 80% that is too much since above 70% the governor does not work fine as it can be appreciated in the Jlog logs. Lowering to 70% is on the other side bad because the tail does not have the power and 105 tail blades seem to be needed. I need a different motor but really I do not want to fly to more than 1700-1800 rpm that is what I fly in other 700 helis.

The tail has been oscillating till I decreased the menu parameter D (tail heading lock gain) from normal to low. Other controls like the dial C (tail dynamic) did not make a big difference for me. The tail gyro gain is close to the maximum (L or M). The control behaviour (parameter B) is red or pro mode. I also decreased the parameter C (swashplate pitch compensation one step down to low) since in this way it flies more similar to vstabi that I am used to.

I really need 3300 lipos to make it fly nicely. With heavier lipos (3700 or 4000 that is what fits in the heli) the tail seems to be lacking power (more lift, more torque to compensate and more work for the tail), specially appreciated in the vertical tic tocs that are not straight and it is probably asking for bigger tail blades or more rpm.

There is an interesting post in a german forum on the tail blades, that is what is giving me trouble. This heli is like an stretched 50, just a 50 with a longer boom if I am not mistaken.

http://www.rc-heli.de/board/showthre...&highlight=105

I am happy with it but it is not being easy to adjust mainly due to the tail. Hopefully the weather becomes better and I can make a video (do not expect too much from my flying skills)

Garfield, do you already have your lipos?

Carlos

[garfield2412]

hi Druekerfish,

no the german custom crew and i had a little "fun" last friday...
they don't believe the payed (cheap) price for my lipos.. paypal and hobbyking invoice wasn't enough for them to believe... Stupid little girl at the custom-team, i think she has just maiden her custom-scool...
i'll have to go there once again and show an original credit card bill of the paypal payment.
that sucks... this girl killed my complete weekend

so i decided to mount an scorpion 4025 to my roxxter 33 and had a little fun with the improved headspeed :-)

sorry i really wanted to write some maiden news this sunday...

interesting post @the german forum!

[garfield2412]

just stupid customs crew...!
went to the office, talked to another woman and she just wondered about the extra credit card bill i wanted so show to her..
got my parcel without any problems.
german customs... no more words on this stupid action..

here they are:
shiny and full of lots of power in a few hours
came 50% charged and verry well ballanced! i just love them! compared to the price and my flight style they are the best choice for me.


i hope the weather will be better at wednesday.. my fingers are very nervous, especialy my pitch thumb

[Druekerfish]

Garfield. I am very interested on the performance of the nano tech with 12S. Are you cycling them a couple of times in the ladder? It normally takes a few cycles till you see the real performance of the lipo.

Below a video of mine. It has some tail wobble problems coupled with the nick, specially appreciated at the end. I am checking for a solution in the microbeast forum, it can come from the pad, the servos, the arms, the blades, the governor, the gains (the solution to decrease the heading hold gain seems to be the proper one. It improved mine, but not fully). The small diameter stretched boom of the heli does not give much confidence, but it is supposed to work in the nitro and other configs. With the Kypom 3300 mAh lipos that are lighter and probably give more rpm, it is better, I will upload the video tomorrow.

[ame]http://www.youtube.com/watch?v=7GhQo0-ahq8[/ame]

Today the thread of one of the screws that holds the canopy was damaged. Aluminium is not the best material for them. They are iron in the Joker and other 700 helis for some reason :-)

[garfield2412]

i'll post the performance of the nano tech just right after my maiden ;-)
but i'm not an 3D pilot, so i can only explain the performance compared to my flight style (sports flying with a few cool moves like rolls, (piro)loops, inverted, rainbows, inverted piro, ...)
but i expect flight times about 6-7min or greater with this setup compared to my flight style.
maybe i'll put my keychain-cam on my head and make a self video of my maiden.

i think cycling them a few times will be a great idea... maybe i'll do that this evening!
so we can also see how many capacity they really have.

microbeast: did you see the guides for tail-setup and caclic setup for the microbeast at the microbeast forum?
my roxxter was set up the way described in this guide and this solved many mysterious problems (especialy some bouncing at hard stops and fast pitch movements, or the back-bounce of the tail at hard stops out of piro.for my roxxter i decreased pot 3 from 8 to 9, decreased pot 2 from 9 to 8 and increased pot 1 1mm.
i'll follow this guide for my EP90 setup the same way. starting at 9 o clock at all pot. this guide explains, that you should set up HH-gain in the menu to lowest value, then do a FF-flight. set up your master gain, until there is no bounce, after that decrease 3-5% master-gain (gyro) once again. then go back in the parameter-menu and increase the HH-gain to the standard or higher value.

never heared about kypom LiPo, are they good? price?

i don't like the way the canopy is fixed! if you have a good soloution, just post it here :-)

Originally Posted by Druekerfish

Garfield. I am very interested on the performance of the nano tech with 12S. Are you cycling them a couple of times in the ladder? It normally takes a few cycles till you see the real performance of the lipo.

Below a video of mine. It has some tail wobble problems coupled with the nick, specially appreciated at the end. I am checking for a solution in the microbeast forum, it can come from the pad, the servos, the arms, the blades, the governor, the gains (the solution to decrease the heading hold gain seems to be the proper one. It improved mine, but not fully). The small diameter stretched boom of the heli does not give much confidence, but it is supposed to work in the nitro and other configs. With the Kypom 3300 mAh lipos that are lighter and probably give more rpm, it is better, I will upload the video tomorrow.


Today the thread of one of the screws that holds the canopy was damaged. Aluminium is not the best material for them. They are iron in the Joker and other 700 helis for some reason :-)

[Druekerfish]

Hi Garfield. I look forward to your maiden flight. Mine is improving after decreasing the HH gain to the minimum and raising the gyro gain to the maximum, The problem is that I am trapped because when I try to increase the HH gain or to decrease the gyro gain (aux channel) the nick flips start to oscillate and the vertical tic tocs become worse. I really did not try the exact procedure, may be I will do it but I suspect I will conclude the same. There are 4 factors that affect a lot (HH gain, gyro gain, tail servo arm length and rpm) the rest like the dials do not seem to have much impact.

Which rpm are you planning? I suspect if you go above 2000 it will be better. I prefer to fly around 1700-1800 rpm and another problem is that the resonance of this heli is around 1500 rpm. It may happen that my problem is derived from getting into the resonance area in the flips and tic tocs.

In any way I am satisfied with the performance now, flips are Ok and vertical tic tocs are quite acceptable, it is a matter of tweaking it a bit further if I have the time. May be I will order the 100 MG and will try the pyro again, I will replace the Align tail servo with a BLS or try the vstabi if I swap it with another heli.

Kypom lipos are quite OK, a bit more pricy than the HK. I get them from http://www.raptor-parts.de/

The problem from the canopy is that the holder has a different (smaller) size than the hole and it damages the thread very easily. I am using a normal M3 screw till I find something more appropriated.

[garfield2412]

i watched your video and i'm impressed of the sound of the heli :-)
i love the blade sound and the sound of the motor power that is beeing freed when you push it harder.
very nice flight! i wish my skills improve faster, i can do the funnels and hurricanes like you, but only at the sim ;-). when did you start flying heli's?

i plan to fly with 1500rpm for liftoff (normal) and then pull the trigger idle1 to 1800. idle2 will be 1898 rpm (95% throttle). that's the set of the rpm points i programmed my CC 120 ICE.
1900rpm should be the max with 105 TBlades according to the manual.

but i'm honest: i don't see any tail wag in your video, but i think that's just a qustion of "i don't know it better, because i'm only an advanced pilot".

so let's go to work and put some straps to the battery tray to fix my lipo's. without them it will be a short flight

Originally Posted by Druekerfish

Hi Garfield. I look forward to your maiden flight. Mine is improving after decreasing the HH gain to the minimum and raising the gyro gain to the maximum, The problem is that I am trapped because when I try to increase the HH gain or to decrease the gyro gain (aux channel) the nick flips start to oscillate and the vertical tic tocs become worse. I really did not try the exact procedure, may be I will do it but I suspect I will conclude the same. There are 4 factors that affect a lot (HH gain, gyro gain, tail servo arm length and rpm) the rest like the dials do not seem to have much impact.

Which rpm are you planning? I suspect if you go above 2000 it will be better. I prefer to fly around 1700-1800 rpm and another problem is that the resonance of this heli is around 1500 rpm. It may happen that my problem is derived from getting into the resonance area in the flips and tic tocs.

In any way I am satisfied with the performance now, flips are Ok and vertical tic tocs are quite acceptable, it is a matter of tweaking it a bit further if I have the time. May be I will order the 100 MG and will try the pyro again, I will replace the Align tail servo with a BLS or try the vstabi if I swap it with another heli.

Kypom lipos are quite OK, a bit more pricy than the HK. I get them from http://www.raptor-parts.de/

The problem from the canopy is that the holder has a different (smaller) size than the hole and it damages the thread very easily. I am using a normal M3 screw till I find something more appropriated.

[Druekerfish]

If you can in the sim it will work soon in real. It is a matter also to learn to steer the heli while doing the manoeuvre because in the real world there is wind and you do care about flying here or there. I am also practising this manoeuvres like you and trying to lern new ones.

Check 4:03, the oscillations are very clear. Life it can be seen clearly in other parts like vertical tic tocs, but in the video they are not so noticeable. The video was with HH gain at low and now after changing to very low(purple) it has improved and it does not oscillate in the flips, only a bit in the tic tocs, but they look OK. At the beginning I am also gearing up because the heli is shaking at idle 1 with 60% throttle.

Hopefully with the 500 KV motor and the 100 MG you will be at higher rpm and have less trouble. I am interested to know.

[garfield2412]

just another question: how did you fix the lipos? i have 3 straps (one for the front lipo and two for the back lipo) and one strap at the end of the frame so my lipos can' "drop out" at stall flight...
i also have 2 velco 2x2 cm stripes to fix the batteries (one per batt), but i think they are too small! the glue on the lipo's doesnt fix the small stripe very well. and one stripe for one lipo seems to bee to less fix.

[Druekerfish]

You can see in the picture of the previous page. I fix every lipo with two straps plus two additional straps at the beginning and end of the frame. I do not fix them to the frame and they do not seem to slip. The area below the motor is quite dangerous because all the cables and balancers end up there and I normaly have to put additional straps to avoid them getting in contact with the motor and also to avoid that the cables move up and are scrapped by the motor. Quite tedious. The motor would be better located closer to the blades like in other similar helis.

[Druekerfish]

BTW, did you ream the ball links? They are very hard for me in the cyclic and the tail, and it seems to be a must for this heli:

http://www.beastx.com/showthread.php...ted=1#post9517

[garfield2412]

hi,

YEAH, did it!
Bad weather, cold but dry. Put it on the ground, fliped throttle "normal" (1500rpm) and the head began to spin.
I was a little bit nervous, but i slighty pushed the pitch until the heli lifted in the air.
The feeling was just awsome! Like a big airplane this heli just hovered like rails on in the sky, or you can explain it this way:

These Rocks are like the EP90 with Microbeast:
VERRY WELL BALANCED IN THE AIR :-)

i decided to hover a little bit more, figured an 8 and checked the gain. just great flying.
adjusted the gain and hovered a little bit more. still awsome, maybe gain setup was to low.
I decided to go to HS 1700rpm and then: the heli began to drift to the left side, i flew another 8 and had many problems to correct it. i noticed some strange sound (vibration). back at "normal" HS 1500rpm everything was fine.
these vibrations are causing drifting problems with the beast!

so i can say: great heli, but some strange vibrations at higher HS (i think they are caused by the tail).
back @home i did a workbech test without tail-blades and main blades. you can notice some vibration at 1500 and at 1700 it get's stronger, you can almost see it.

decided to check belt tension, was a little bit loose and checked my gear-mesh, was a little bit tight. so i changed that.
feels a little bit better now, but that may be a huge problem. you can see the MB shaking a little bit!

any suggestions? the vibration causes the push rod to the tail-blades to vibrate at a loud noise.
i hope i figured out the problems by changing belt tension and gear mesh.
what tape did you chose? the hard one --> 3M?

turnigy nano-tec: JUST GREAT, but i did a big mistake. i did set my CC to 3.0V cutoff (dumb noob failure). so i squeezed all the amps out of it. back at the charger i pushed back 2x5600mah ! THATS more than the nominal capacity (4500mah). so i think 600mah are charger fault-count and 5000mah are the real value. good lipo, i can tell you more values when the vibration-problems are gone.

[Druekerfish]

Congratulations for that maiden flight. My experience is that this heli needs a bit tweaking. The tail is better with 95 mm blades as starting point. The shaking @ 1500 rpm is because it has resonance around that headspeed, may be it is different in yours depending on the blades and how tight they are. You can see in the previous video (better) and in the one below that at the beginning the vertical estabilizer shakes always when crossing around 1500 rpm, go to HD if you do not appreciate it. I had lowered the Jive to 60% and I was in that area. I had to idle up to 70 and 80% to get out of the resonance. This heli is designed for higer rpms. For lower it is probably needed to change the dampers.

Now the tail of my heli is making sense after the reaming. I have been reticent to do it since I prefer to be on the safe side and I always had helis with much less links where the reaming is not really needed. I can have now the heading hold and the gyro gain in normal values. The vertical tic tocs oscillate a bit, but it is improved by increasing the rpm

I am using the Mikado pad that is quite hard and does not break apart like others.

This is the other video, same flying as the other since it is from the same day, I was still wondering what happened to the tail . Now it is solved

[ame]http://www.youtube.com/watch?v=rB_QCZ5Gqlg[/ame]

[garfield2412]

great flight!
the tail seems to be very stable now. no more oscilation like @minute 4:02 on first vid.
congratulations!

yeah. maybe the rpm is a big factor at these wired vibrations.
but i don't think it comes from the tail blades, but i ordered some edge 95mm right now and have a try.
these vibrations are also there without TB and MB and @1700rpm.
but you are right, can be the factor of the slight larger main-blades, coresponding to motor rpm, or the fact of your 400rpm/v scorpion vs my 500rpm/v scorpion that these vibrations start at different rpm.
i hope i solved some vibrations.. 1500rm will not be my flight rpm, just for liftof and landings, but 1700 WILL BE. but maybe i raise the CC setings to 1750 or 1800 to test the difference.
also i'll try my 1900 next time..

thanks a lot for your help!

Originally Posted by Druekerfish

Congratulations for that maiden flight. My experience is that this heli needs a bit tweaking. The tail is better with 95 mm blades as starting point. The shaking @ 1500 rpm is because it has resonance around that headspeed, may be it is different in yours depending on the blades and how tight they are. You can see in the previous video (better) and in the one below that at the beginning the vertical estabilizer shakes always when crossing around 1500 rpm, go to HD if you do not appreciate it. I had lowered the Jive to 60% and I was in that area. I had to idle up to 70 and 80% to get out of the resonance. This heli is designed for higer rpms. For lower it is probably needed to change the dampers.

Now the tail of my heli is making sense after the reaming. I have been reticent to do it since I prefer to be on the save side and I always had helis with much less links where the reaming is not really needed. I can have now the heading hold and the gyro gain in normal values. The vertical tic tocs oscillate a bit, but it is improved by increasing the rpm

I am using the Mikado pad that is quite hard and does not break apart like others.

This is the other video, same flying as the other since it is from the same day, I was still wondering what happened to the tail . Now it is solved

[Druekerfish]

Yes, you should try various rpm´s. I was also quite puzzled when I reduced the idle up values at home, went to the field and saw the Xtreme shaking without apparent reason, till I realized. I also do not understand why the resonance is at that value, I also planned to fly around 1700-1800, other similar helis have the resonance below 1000 rpm. There may be other dampers to choose and get the resonance out of that rpms. According to Uwe Caspart, a RJX team pilot, the best performance is around 1850-1950 rpm. This heli is not easy to set-up: the tail blades, the belt tension, these resonances, the ball links, uuups! I have been very lucky to have the help of one of the RJX team pilots, and I am sure that I still need him further.

[garfield2412]

really? lucky guy, i watched some movies from him and saw him flying @ghm in augsburg.
he flies in goldboden/schorndorf/germany? thats only 20km from here.

[Druekerfish]

BTW Garfield, I see that you have no washers in the bolts that fix the motor. I think the bolts are in the kit but no washers, that is why we are not installing them. Mine started to move and to open the aluminium motor plate. I think it is important to put some, specially with the Scorpions that have smaller bolts.

[garfield2412]

thats an very good idea Druekerfish! I'll change that imidiately.
i visited Michael, the german importer of rjx parts yesterday, because i needed some spare parts for an TT-tail that i want to install maybe in the future. (repair laurens TT-tail, only the gear was destroyed.)
i asked him some questions about vibrations, here are the answers/soloutions:
1. glue the bearing where the motor pinion goes in to the bearing-block
2. pay atention on scorpions, they vibrate sometimes out of the box
3. main-shaft may be not straigt (out of the box)!
4. ream the push-pull (you allready told me that)

so lets get to work, maybe i'll do an video of second flight today.

Originally Posted by Druekerfish

BTW Garfield, I see that you have no washers in the bolts that fix the motor. I think the bolts are in the kit but no washers, that is why we are not installing them. Mine started to move and to open the aluminium motor plate. I think it is important to put some, specially with the Scorpions that have smaller bolts.

[Druekerfish]

Yesterday I lost the tail and the problem seems to be that the 14 mm pin that holds the pulley went off. I broke my allen tool while trying to remove the set screw. Watch it out!

Edited:
It is necessary to file a bit the pin in the area where it is hold by the set screw. Otherwise it will go off and the tail will start spinning. It is awful that this and other issues are not properly documented in the manual that is still v1.0

Yes Garfield. We want a video!

[garfield2412]

bad luck today... windy and strong gusts. there are some guys here doing kite surfing with an "car". they look verry happy about their top speeds!
my roxxter was jumping up and down in the air, so i think it will be s bad idea to try another rjx 90ep flight :-( maybe later..