TDR Technical Stuff (Tips) & Build Videos

[jointer]

I get it, but i never tried move the grips when the tail is spinning, but i have seen Heim Joint video about it.
I just do not see any assymetric part on the grips which should compensate that.
Like this:
https://www.helifreak.com/attachment...9&d=1228219664
Or homemade:
http://www.mycoolheli.com/PICS/EXI500Weightmod.jpg

EDIT:
Or like Joker:
http://file.espritmodel.com/heli/joker26.jpg

Then MAYBE using 1mm longer screws might have effect on that, due to the fast spinning tail?
If i mount the screws opposite (not nut inside, but outside), which moves the tiny aditional weight from internal side to external, should i see opposite behaviour?
Meaning it will not "bounce" on tail left stop, but on the right stop?
I have the screw sticking out from the nut about 0.3mm.

[OICU812]

I have longer bolts to, no ill effect so that's not it.

[ZuvieleTeile]

The pics you attached show the weights built in the cast or added through washers.
Thats perfect.
Jan took a more elegant and much easier to manufacture approach.
See the attached pic. He made the grips wider for future bigger tail blades and added through this measure exact the additional weight, 90 degrees from the balls and in the proper distance from the pivot point to compensate for the little metal arms and the balls.

The weight have always to be distributed on both side of the blade grip. Never only outside or inside.
If add too much weight you get the opposite effect. Now the tail servo has to fight the weight.

Really, the only way to figure out, if it is the correct weight, is through the procedure I described above. If the heli is mounted on a heli stand and all the blades are removed, it is safe and effective.

KR
ZT

[jointer]

We tried today.
Grips without screws - very hard to move the tail pitch with hand!
We were actually very surprised by this!
Grips with longer screws but mounted with nut out - not much force needed, seems fine.
Grips with longer screws correctly mounted - we forgot to test that.
Grips with stock screws mounted as manual suggests - not much force needed, but the tail have tendency to center itself.
BUT after mounting the blades, stock screw is not long enough to be locked by the nylon part of the nut, so i consider using it dangerous, it will not hold.

We were (with my experienced friend) thinking the "advance" of the tail blade should also matter, like the flybarless main blades which should have neutral center if you hang it by the hole.

It could have effect on the servo, like on cyclic when you use too agressive blades, it stress the servo.

We did not tried to spin it with the tail blades, because we did not know what will happen, if we will be able to hold the heli down.

It is hard to believe the part on the image is enough, but i will believe it is.
I also found the maximum operating temperature of BLS251 is 60 degrees, which i have just after first flight in hot weather.
I will lower the gain a bit and see how it will work out now.
I also replaced the plastic arm with new one, after 80 flights there was about 1mm play, but only in hover position (servo arm 90 degrees to tail control rod).
I probably hover too much.

[helicraze]

I replaced my stock tail blade bolts with slightly longer ones as mine did not touch the nylock. Anyone else notice the tails are quite stiff to move? I used radix 105MM and only just tighten the bolt/nut so its not spinning but the tails are quite firm. Seems fine in flight

[aussiemick]

Stiff but smooth.

I am amazed how tight I have to tighten the main blades to stop them folding in on spoolup, the first few outings was majorly scary till the headspeed advanced enough to hold the blades out straight.

Mick

[helicraze]

Thanks, I also had to tighten my main blades a bit

[jointer]

Same experience here.
Helicraze, if you will have time, can you measure temp of your tailservo after flight and also write what gains and maybe Vbar changes you have?
The BLS251 temps really worries me, i was warned that there might be thermal problems with the Jive, but hot tailservo is a surprise, i must focus on it.

[helicraze]

Mine is about 10deg above ambient from memory, on a cold day i can hardly tell with my finger, sometimes i wonder is it from the enclosed canopy and the motor heat.

I have stock file but changed (14deg, 1850RPM): i gain 55, tail gain 95, precomp 18/9, accel 65.

Thats it.

[jointer]

Helicraze i have currently same settings like you, because i tuned the tail and ended there too (and i was later inspired by your numbers).
Maybe i have too high expectations how well the tail should hold.
I think precomp is still not high enough, because the tail slides out slightly for example in descent stopped by using fast cyclic input.
But i want to fly safely and comfortable and not to worry about things like this.
I am switching gain 120/105/90 percent depending on RPM.

[helicraze]

My tail on the 2010 TDR holds very well, the 2009 is not as good it kicks sometimes due to plastic tail blade holders i think.

It will not blow out, hold better than the trex 700e i had

[Heli G]

I used the stock bolts in the tail and can reach the nylon part of the nut – am using Jan’s tail blades at present. I haven’t done a bench test to see the “Chinese weight” effect with the TDR, but my experience on the Trex500 is that the bolts (am using Heim Joints) make a huge positive difference on the bench test and in flight, especially fast piros.

Like HC’s, my tail is super solid and absolutely perfect – fast punch outs, piros, speed flights no matter what I throw at it – running 1700rpm, but will go to 1850rpm and report back. Only change from Jan’s stock settings has been the rate which I have set to 100. Joint, you should have high expectations on the tail hold as mine is unbelievable. I’ve been flying with Spartan gyros and thought they were superb, but the 251/mini-vbar on the TDR is even better in my opinion which I believe has a lot to do with the good design, quality parts and vibration-free setup. I haven’t hovered much with the TDR as I just love flying it so much, but as far as I can recall it doesn’t act any different when taking off or coming in to land than its superb handling during flight.

I will check the 251 servo temp on the weekend, but I can’t recall it being hot. We are flying in “cooler” temps at present (60-70F), so it will also have an influence.

The tail slider assembly has also appeared stiffer than what I am used to. I did find a small “notch” but it ended up being a very small burr in the tail center hub. After removal the slider was still stiff but very smooth. I get the feeling that the design was done that way and is part of why the tail performs so well on the TDR – it probably also causes the tail servo to work a bit harder and may be something to consider if the 251 temp is too high.

I’ve also noticed that the main blades are very loose and you have to tighten the bolts quite a bit. I actually tightened mine up a few times till I got the right balance before my maiden – reason being that the longer and heavier blades cause quite a bit of difference in the stiffness at the blades grip compared to a 500 size which I am familiar with. But, they are perfect now and I have a good feel for how tight it should be. I was also quite surprised by how well Jan’s stock blades (it says “Rigid” on them) are performing. I need to test my Radix as well but I am having so much fun with the current setup that I don’t want to change…

Re gear mesh and “stripping”, did you guys apply grease? I used the white lithium grease and so far it looks to be working very well to keep the friction lower. Granted, we haven’t seen high temps so I will have to keep a lookout for this in summer.

I’ve also gone through all the bolts/nuts after the first few flights just to make sure everything is still tight. I did notice that both the front cyclic servos were loosening from their plates (0642) a bit – I didn’t apply loctite to the bolts during the build as this was not required in Jan’s manual, but have subsequently loctited them and they are now fixed after a second round of flights and checks.

My only complaint is that the TDR is flying so nicely that I can see my Trex500 getting shelved. I was considering doing a FBL conversion on the 500 but I think it will be effort better spend on a 2nd TDR this year – I have one on order for 2011, but with Jan not making any changes there’s no reason to wait, apart from being in the back of the queue that is.

[nyc863]

speaking of bolts.
The rudder servo is held by two bolts and this allows the servo to pivot for maintenance. You need to make sure those suckers are tight and stay so -- otherwise the servo can push itself out of vertical to the frame. The first sign of that is what was a perfect CW/CCW number suddenly needs a bit of adjustment.

[Heli G]

Originally Posted by jointer

The BLS251 temps really worries me, i was warned that there might be thermal problems with the Jive, but hot tailservo is a surprise, i must focus on it.

Joint, I had a look at the 251 temp today and I could not get it to get hot al all. It was light warm to the touch, but no more than the Jive120. I tried again later with two flights straight after each other – as long as it took to change the batts. Same result, pleasant light warm to the touch but nowhere near hot.
If it helps we were flying in temps just shy of 20 C.

[Heli G]

Originally Posted by helicraze

I didn't in the beginning at it felt fine, but now will add them in as i can slide the grips slightly.

After about 15 flights I found some play (+-8mm) at the blade ends, assuming as things have settled – time for another set of spacers.

[nyc863]

I have about 1cm of teeter in the head (measured at the tip), but no axial play. So I'm not sure how spacers are going to reduce teeter. The teeter comes with a slight click or tap noise as I push it up and down.

[ZuvieleTeile]

The click noise comes from the delrin bushing when it hits the feathering shaft.
The only thing what additional shims can do probably is, putting some pressure on the o-rings which reduces then play there, but not on the bushing/shaft combination.

KR
ZT

[Heli G]

Originally Posted by ZuvieleTeile

The click noise comes from the delrin bushing when it hits the feathering shaft.
The only thing what additional shims can do probably is, putting some pressure on the o-rings which reduces then play there, but not on the bushing/shaft combination.

KR
ZT

Yep, adding a thin spacer between the bushing and first bearing compresses the damper more, reducing the teetering.

[helicraze]

I have now replaced my black oring carriers with the white 2009 versions, so no teetering/head rocking, also removed the grub screw and put a red oring inner and black oring outer. I checked with Jan and its ok to do if you prefer the head this way.

I certainly do, the MPXLE and 2009 TDR fly nicer IMO than the 2010 head. The 2010 head only give benifit of no bobbing at any RPM range. The older heads can bob at 1500RPM but i don't care i only fly at 1850 and prefer the dampning properties of the older head, more precise and no pitch up in FFF.

If you order some spares get the 2009 spacer and some orings, much nicer IMO

[Heli G]

Originally Posted by helicraze

I have now replaced my black oring carriers with the white 2009 versions, so no teetering/head rocking, also removed the grub screw and put a red oring inner and black oring outer. I checked with Jan and its ok to do if you prefer the head this way.

I certainly do, the MPXLE and 2009 TDR fly nicer IMO than the 2010 head. The 2010 head only give benifit of no bobbing at any RPM range. The older heads can bob at 1500RPM but i don't care i only fly at 1850 and prefer the dampning properties of the older head, more precise and no pitch up in FFF.

If you order some spares get the 2009 spacer and some orings, much nicer IMO

HC, what’s the difference between the white and black bushings (0109)? Also, my understanding is that the red o-rings are softer than the black ones, which will probably result in slightly more teetering than just using two black ones?
I had a look at the teetering last night and the bushing is already very tight against the centre hub (0120) so it won’t compress the o-rings any further. Only thing I can think of is replacing the o-rings.
I’ve also shot an email off to Jan to get his view on what an acceptable level of teetering is at the blade tips. I have a feeling that 8mm is too much.