Best alternate bolts for tail blade grips

[ZuvieleTeile]

Originally Posted by Dumbthumb75

In this example, I belive the 18-8 stands for the quality/ "blend" of stainless steel. Not tensile strength...

True,
18-8 is the nice and shiny stuff your kitchen sink is made of. . .

[mkovalcson]

So are you guys actually concerned that it isn't strong enough to hold a tail blade on?

[ZuvieleTeile]

Originally Posted by mkovalcson

So are you guys actually concerned that it isn't strong enough to hold a tail blade on?

I wouldn't be concerned about that.
My 600 size Henseleit MP-E flew with 3 mm bolts on the main blades. . . and they didn't come off.
There is no way, that the tiny tail blade shear off the bolt . . but stainless steel is prone to vibration fatigue.
I don't remember the number anymore, but after such and such billion vibs it just brakes like glass.

[DT75]

Originally Posted by mkovalcson

So are you guys actually concerned that it isn't strong enough to hold a tail blade on?

No, I wouldn't worry. 6,5 gr of tailblade won't break any M3 bolt.

[DT75]

How about this one ?






Not a tail, but a mainblade bolt.

Posted by a speedflieger, running a B/E Pyro, 16T pinion, 2400 headspeed, and 235 gr blades.

The thread is in german of course...:

http://www.rc-heli.de/board/showthread.php?t=192979

[Groucho_]

How about that one?

Can't see it... The site wants me to register...

I did try, but I can't understand that specific bavarian dialect that they're using (And neither can google translate apparently)

[DT75]

Registering is free. (I had to use the translator to do so...)


Here's the slightly edited OP :

Hi all,

letzens I accidentally times the main rotor blades bolted down my Speedrigids. Even when turning to notice that the screw was turning at every turn somewhere stricter. Critically, it was then the pull out from the rotor blade. The screw verkanntete fairly, but then went out and fortunately.

You could see with the naked eye, which had to be bent screw. So also the second Sheet screwed down - with the same result as with the other rotor blade.

Now it gets interesting: the helicopter had no Umkipper etc, the screws were only max. 25 flights on it. Almost 2 weeks before that, I had the screws down here also, what about the helicopter set. There was bent yet.
I just changed my battery, at this air show, it was a new wave 12s Power 5000mAh 40C.
This was after flying quite warm (almost 50 degrees)

Can it be that only a new battery the same speed all the high rises so distinctive that it can bend a bolt suddenly?
The Jive is working with me in the mode 4

Did anyone of you have such a problem?

When I have a 16er gear with which you should have about 2400 rpm.

Including motor control of the Black Edition is the Kontronik.

As a remedy, I shall now remove the tubes from the rotor blades (thus, a larger screw is used), sit down with Jan Henseleit together (because of the quality of screws) and drill out the hole in the blade grip something.



And this is Jan's reply :

shocked I just read your thread.
To operate with a 16 mm pinion leaves 235g is beyond good and evil!
So you come in the downturn or on the floor at 0 degrees pitch at 2600 U min easy / and so on more than 800kg centrifugal forces.
The whole thing is not only exceeds the ultimate strength of the bolts but is also completely pointless.
First, it creates the engine anyway, far from keeping this speed under load and still you do not need as well as a speed at 235g leaves.
There were 2100 U / min more than adequate. With 200g of leaves, we go way up on 2300U/min what works without any problems.
Furthermore, I also advise strongly against it to drill the holes in the blade grips just because it will never work exactly the angle and thus the next problems are inevitable.
Furthermore, this use is not much, because then they bend but do not screw, but the risk of tearing the M5 screw the blade pivot shaft that is not banned.
I believe that no one can really imagine what happens then!

Jan Henseleit


Posted 'cause I thougth it was funny, + there are some interesing posts in that thread, I think.

Safe to say the guy was pushing the limits on this one...


Sorry for hijacking the thread...

[Groucho_]

Well all this is plainly a moot point if the helicopter had no Umkipper...

[mkovalcson]

New tail bolt on the left, Original on the right.

I'll need to spin it up. Hopefully it won't vibrate or have issues because of more weight being on the nut side of the bolt.

[Danny_Swe]

I have 10 flights with my new bolts, also 30mm (looks like on your pic) and no issues, seems like a good upgrade

[ZuvieleTeile]

[quote=mkovalcson;3810996]New tail bolt on the left, Original on the right.

I'll need to spin it up. Hopefully it won't vibrate or have issues because of more weight being on the nut side of the bolt.


Mark, don't spin it up like this!!
The bolts/nuts and bigger claws of the new tail blade grips are very fine tuned as chinese weights.
If you insist, at least set the heli in a angle to you. The flying blade might injure you.
The TDR has a higher head to tail ration than any other heli.

[Groucho_]

Originally Posted by ZuvieleTeile

[I]
Mark, don't spin it up like this!!
The bolts/nuts and bigger claws of the new tail blade grips are very fine tuned as chinese weights.
If you insist, at least set the heli in a angle to you. The flying blade might injure you.
The TDR has a higher head to tail ration than any other heli.

Seriously?!

Can you elaborate on this please?

Would this mean that we should use only original TDR nuts and bolts when we need to replace such items?

Thanks.

[ZuvieleTeile]

I am talking only about the tail grips.
Remember the earlier versions of the Henseleits like the MP-E had already brass chinese weights on the tail grips. They compensated for the force of the spinning ball links on the tail blade grips. Servo has much less work to do.
Just have a look at the grips of the TDR.
The claw part is bigger than the bearing part. That acts like a chinese weight.
The older versions (up to TDR) had the claw part smaller and weight had to be added.
Just adding a millimeter or so to the bolt, until it reaches the end of the lock nut, wouln't be a problem, hopefully.
But don't get a bolt what sticks out at the end. . .

[mkovalcson]

So far there are no issues I flew it at 24%, 48% and 60% today and had absolutely zero tail vibration, tail wag or even a hickup during spin up just smooth as silk.

This thing tracks like it is on rails, just smooth as silk.

I feel like I'm making a lot of progress this week just flying a few packs a day.

I like the TDR with the 13T and the long flight times, but I may try out the 14T pinion in a month just to see how it feels compared to this.

[Danny_Swe]

yes... it really is a confidence-machine so smooth, precise and predictable. I have like +20 flights on mine now and today I dared try new things I've never done before, not even in sim it flies so good!

[CACN]

I've asked Jan about the tail blade grips' bolts being a little too short and if I should replace them with 20mm bolts. Here is Jan's reply.

normally the M3x18 screw should cover half of the plastic which is enough.
If not take a little loctite for secure the nut.
M3x20 screw can have a negative influence to the self-aligningtorque which has to be positive but as less as possible.

Best Regards
Jan

[Danny_Swe]

ok!? well I think I'll cut mine to 19 mm then!

[DT75]

Originally Posted by CACN

I've asked Jan about the tail blade grips' bolts being a little too short and if I should replace them with 20mm bolts. Here is Jan's reply.

normally the M3x18 screw should cover half of the plastic which is enough.
If not take a little loctite for secure the nut.
M3x20 screw can have a negative influence to the self-aligningtorque which has to be positive but as less as possible.

Best Regards
Jan

Looks like I'll have to shave off a mm. too...

Thanks.

[Groucho_]

What nonsense...

But still I've gone and did the bolt reduction...

A few seconds with a dremel, and it's sanded to size.

A little tip if you're going to do this - screw on another nut on the bolt when you remove it from the grips. Leave the amount you want to sand down protruding from the nut, then sand away.

This way it's easy to see that you've taken the exact amount of metal away...

BEFORE

AFTER

[Danny_Swe]

Look what I found deep down in my pile of stuff.

http://helidirect.com/t-rex-500-flyb...er-p-14304.hdx


.........

They were perfect when cutted 1 mm, look: