TDR Technical Stuff (Tips) & Build Videos

[Mercuriell]

I can see the there's going to be a lot of TDRs out there in the future so I thought I'd start a technical tips thread - by all means discuss and I'll do a top of page index for reference

All contributions warmly received !!


A Method to Increase Motor and ESC Cooling Air using a NACA Duct Mod - AussieMick

Henseleit TDR Build Videos - Mercuriell

Tips for VBAR - Helicraze

VBAR mounting

[Mercuriell]

Lost the tail last week and the poor heli ploughed tail first into the field during FBF - not too much damage at all. The post mortem only revealed one possible culprit and that was the threaded pushrod was loose and sliding in the CF tube. I had scoured the inner of the tube with a bit of wire and used 5 min epoxy but obviously not enough.

Didn't have an original Henseleit pushrod so I used an MA CF rod I had handy and made sure the threaded rod and tube degreased in acetone, pumped as much epoxy down the hole as I could and them seeped in some CA at the top for good measure. OICU812 has a good tip and that's putting strips of dental floss down the tube as well

[Stolla]

I've used ca on all my heli's so far so good

[helicraze]

After speaking with John, i replaced my 2 bolts on the main shaft (1 that clamps the rotor hub and the 1 that clamps the gear) with M4 12.9 grade shank bolts.
The ones i pulled out were bent even though they were tight and only done about 30 flights.

[helicraze]

Also I noticed that there is a patch on the main shaft were the swash slides that has a rough patch, but only on one part, its always lubricated, any ideas?

[Mercuriell]

Follwoing a recent boom strike after my tail push rod link came loose I suffered a loss of HS after the rebuild and found the top mast Jesus bolt had sheared. THe bottom mast bolt was also slightly bent. This reinforces the importance that this bolt is done up tight - using an L Allen wrench rather than just a driver as it is the grip of the rotor head collar on the shaft which is supposed to transfer power rather than the bolt. I decided to replace mine with a high tensile collared bolt both top and bottom and it is worth checking after a blade strike!

[OICU812]

John and Micheal, I am building now. Any idea for sure if the 2010 kit bolts for the two on main shaft you speak of are upgraded or higher grade? I'd ask Jan but he is near impossible to get response from as you probably know...

[helicraze]

The 2010 bolts top and bottom of the main shaft are 8.8 grade NON shank. These i replaced without question as precaution, a long shank M4 bolt cut down does the trick.

I noticed Jan supplied 12.9 grade cap screws for the main blade bolts.

[Mercuriell]

It's a difficult call Shawn - in some ways better for a JB to bend rather than break - maybe that is what Jan is thinking of but at least a collared bolt would seem to be ideal rather than threaded - I'm with Michael - I changed to a 12.9 collar. The bottom line is that power of the electric 90s is reaching the edge of the envelope of the traditional materials/sizes we use - I know several manufacturers have had probs with the 10mm mast on the big electrics so maybe it's time for a standard 12mm shaft and M5 JB !!

[OICU812]

Hmm I was very suprised to see M4 main blade bolts for sure, the grip holes should be IMO a 5mm bolt hole. I know there is not much to improve but I did notice a few things in my build. Maybe although short we should start and construct a "Things you'd like to see on TDR revisions" thread and forward to Jan once complete. I have done this with Mikado stuff and it has been really helpfull to the manufacturer and also of course us customers/pilots. Just a thought.

[Heli G]

Originally Posted by OICU812

Maybe although short we should start and construct a "Things you'd like to see on TDR revisions" thread and forward to Jan once complete. I have done this with Mikado stuff and it has been really helpfull to the manufacturer and also of course us customers/pilots. Just a thought.

Great idea!

[ZuvieleTeile]

Originally Posted by OICU812

Hmm I was very suprised to see M4 main blade bolts for sure, the grip holes should be IMO a 5mm bolt hole. I know there is not much to improve but I did notice a few things in my build. Maybe although short we should start and construct a "Things you'd like to see on TDR revisions" thread and forward to Jan once complete. I have done this with Mikado stuff and it has been really helpfull to the manufacturer and also of course us customers/pilots. Just a thought.

Sounds very good to me!!!
Let's start.
I got my TDR 2 days ago and we will see what I come up with and I keep your remarks from this thread in mind when I start building.
Cheers
ZT

[helicraze]

Only things i can think of is:

M5 blade bolts
12.9grade shanked screws in critical areas
More velcro straps in the kit
Spare dampers in the kit (1 set)

Also i found for the metal tails the bolts a little short and only just touching the nylock part of the nut, i replaced it (would also prefer shanked bolts here)

[ZuvieleTeile]

The bolts for the main shaft are 8.8 on purpose.
They have to be "flexible".
And don't worry about the size of the blade bolts.
Remember, the MP-E had/has only 3mm bolts for the main blades. Mine survived 5 bad crashes and they are still ok.
The 4mm for the TDR is more than sufficient.
Jan is not the kind of guy going short-cuts if he has concerns about safety or longevity. Also he takes a lot of things into consideration when it comes to diameters, hardness and/or shaft stiffness.
Take e.g. the feathering shaft.It looks like a plain shaft with 2 threaded holes at the end, right?
For the 2010 model with higher bending forces due to the seesaw bearing in the head and closer bending points, the feathering shaft has been hardened on the surface but softened at the ends again to avoid fatigue cracks at the thinner wall thickness.
These are thoughts and additional steps in the manufacturing process, which makes the difference between "a" Helicopter and a Henseleit.

Cheers
ZT

[helicraze]

I got some spindles but Jan was not sure if they are hardened or not, he said take a small file onto it (I don't have a small file) is there any other way to tell?

[aussiemick]

hit it with a grinder, the sparks will be yellow if it is soft and white if it is hard.

The file will be less invasive. Just get a set of tiny jewellers files from bunnings, cost about $7,00.

Mick

[helicraze]

Just a tip for those of you that have a 2009 TDR or MPXLE if you find you get bent spindles (I had a few) from doing upbrupt stops etc the 2010 hardened spindle will cure this (Jan emailed me about it after a query).

[Heli G]

Did anybody use an additional spacer washer on the spindle between the blade grip and dampers? I see Jan suggests using an additional spacer washer depending on the play.

[aussiemick]

I had to put a second set of spacers in mine, I put them between thrust washer and outer radial bearing.

There was noticeable play without them.

Mick

[Heli G]

Originally Posted by aussiemick

I had to put a second set of spacers in mine, I put them between thrust washer and outer radial bearing.

There was noticeable play without them.

Mick

Thanks Mick. I added an extra pair of washers but now there’s hardly any movement if any. Just wondering if this is what Jan intended with the new design. He mentions the blades should move 3-5mm at the tips, but I’m still building so it’s difficult to judge how much is sufficient.