TDR head question

[Puttputt maru]

Just had a beautiful day of flying with both my TDR.

One thing bothers me and I am not sure if it is normal or not because I did not pay attention to it before.

Both my TDR head have an up and down play when I grab both blade grip, sort of like a seesaw swing action.

Is this normal or did I rebuild them wrong?

[Retired2011]

Mine does it too, and I have also been wondering if it's normal...
two other TDR's I fly with, but I keep forgetting to check theirs too

I'll try to remember tomorrow.

[Puttputt maru]

I got a PM confirmation that it is normal depending on the bushing used. Red/Black combo will have the play. White/black will not.

Always nice to know since none of my other brand helicopters were doing that behaviour.

[Retired2011]

[CyprusFlyer]

Yes its the plastic bush in the head:
Black bush = wobbly head, harder damper o rings (standard)
White bush = tigher more locked in, use the softer red/black combination of o rings.

[SN1975]

Hi Friends,

Like to seek advise and sorry to hijack this thread.

Just got a preowned TDR and the previous owner told me that I need to rebuilt the head cos its notchy. Replaced all the bearings and there is still this "notchiness" as I rotate the blade holders.

Like to know if anyone has experience in what the problem is or is that normal again?

[aziz76]

No that's not normal, I would make sure you have all bearings in the right order/orientation. Also if you just rebuilt with existing parts maybe the thrust bearings (or radials for that matter) are bad and need replacing.

The blade grips should turn very smoothly on the spindle.

[CACN]

Make sure the radial bearings (closer to the hub) are seated properly. TDR has such tight tolerance. Jan has suggested to me that heat the blade grips to install the radial bearings to ensure proper seating.

[SN1975]

Originally Posted by aziz76

No that's not normal, I would make sure you have all bearings in the right order/orientation. Also if you just rebuilt with existing parts maybe the thrust bearings (or radials for that matter) are bad and need replacing.

The blade grips should turn very smoothly on the spindle.

Originally Posted by CACN

Make sure the radial bearings (closer to the hub) are seated properly. TDR has such tight tolerance. Jan has suggested to me that heat the blade grips to install the radial bearings to ensure proper seating.

Thanks everyone. Yah. Should have thought of the thrust bearings. Stupid me. Changed everything. Why not the thrust bearings.

[Groucho_]

If there's one piece of advice I would give to anyone putting a TDR head together, it would be to use a heat gun when installing the bearings.

The bearings should just drop into place with a satisfying looseness.

Any other method is asking for bearings to be ever so slightly not seated and radial bearings damaged upon tightening of the blade grip screws.

I know - I've tried a grip-bearing install shortcut myself and had to redo it.

[SN1975]

Originally Posted by Groucho_

If there's one piece of advice I would give to anyone putting a TDR head together, it would be to use a heat gun when installing the bearings.

The bearings should just drop into place with a satisfying looseness.

Any other method is asking for bearings to be ever so slightly not seated and radial bearings damaged upon tightening of the blade grip screws.

I know - I've tried a grip-bearing install shortcut myself and had to redo it.

OMG, looks like I am in trouble. Cos last night I couldn't get the bearings out at all. Sigh. This is the second set of bearings I installed. Don't have a heat gun too.

I am putting out this appeal to any kind helifreak soul here who might want to help me put the head together and put it right of course. I will send all the needed bearings, take care of the shipping to and back and if you need a small fee for the time and effort.

I think this may reduce my frustration in the long run.

Appealing for help here.

Many thanks.

[Groucho_]

Remain calm.

It's a simple fix. But you really should get yourself a heat gun.

They are inexpensive and indispensable for this sort of situation.

Once you've heated the blade grips with a heat gun the bearings will simply fall out.

I know it seems impossible to believe. I still have trouble believing my eyes every time those bearings fall in and out so effortlessly when I'm installing, and removing them.

Until your heat gun is delivered, you can put the grips in the oven and heat them.

In both cases, use a thick cloth glove or mitt. I use some kind of heavy duty gardening (or maybe it was welding) glove.

[Raptorapture]

Originally Posted by SN1975

OMG, looks like I am in trouble. Cos last night I couldn't get the bearings out at all. Sigh. This is the second set of bearings I installed. Don't have a heat gun too.

I am putting out this appeal to any kind helifreak soul here who might want to help me put the head together and put it right of course. I will send all the needed bearings, take care of the shipping to and back and if you need a small fee for the time and effort.

I think this may reduce my frustration in the long run.

Appealing for help here.

Many thanks.

I've got TDR but never reassembled head, yet

I can loan you a heat gun, shipping not so far

PM sent.

[SN1975]

PM replied

[SN1975]

Hi all,

Like to announce that my problem is sort of settled. Flying buddy very near me owns a heat gun and yup everything just falls apart and falls in place.

And OMG everyone here is right. It's the thrust bearings.

My thanks to Raptorrapture who is so kind to offer help and we had a good chat. Maybe we can get together for a nice fun fly once I get my TDR ready.

[Raptorapture]

Great news! Good chatting. Hope it's in the air soon