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HelicopterScale Model RC Helicopters Docs  Big Huey 212
Thumper217

Senior Heliman

Slidell, LA - USA

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So far my luck with the gears have been fine but I've only spun it up on the bench a few times so far. I will keep you posted although your more likely to get your in the air before I do.

I like that mod you made to the gear box for the bell crank. I haven't decided how I'm going to control the tail yet. I might use a servo mounted in the tail to avoid the use of a bell crank or I might use some flexible "Golden Rod" mounted in some brass tubing for support. But after seeing your mod I might go with a traditional push rod.

Andrew

Thumper

02-08-2017 02:45 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Thanks Andrew. IMHO the size of the TR disc in this heli is a bit on the big side for goldenrod. Plus, you probably don't want any more weight that far back in the fuse. You can do it, but it will take a lot more ballast in the nose.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

02-08-2017 03:38 AM
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Dr.Tim

Elite Veteran

Mojave Desert

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One word .. OK maybe two .. Flex Drive. I know some hate them but they are easy to set up and WORK!! All of my Large Turbine and Gasser scale helicopters use a Flex Drive!

From Simple minds come simple ideas! Approach Engineering

02-09-2017 06:07 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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I agree Tim, your flex drives do work very nicely. I just decided that I was going to build this one the way vario designed it...

So, I need to cut open a section of the tail boom for access to the 47 degree GB. Then I need to mold a new section to replace the one that I'm cutting out. I made a paper template, then traced it out on the boom. Then I taped down some release ply and laid 4 layers of 6oz glass cloth over it. Popped it off the TB and what I have is a female mold for the replacement part.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

02-12-2017 01:45 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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I just got back to working on the 212. I cut out the GB access panel and got everything lined up. I didn't want to cut the boom, but the longer I waited and more I thought about it, it was obvious that it needed to be done. This access hole made setting up the tail much easier. Otherwise, you're just guessing where everything goes and there's no way to fasten the vertical boom section to the intermediate GB (unless you bond it). You also can't attach the TR Op rod to the bell crank with no access.

I pre-fit the torque tube donut in the boom and bonded the wood backing plate to the tail adapter. I also bonded the blind nuts to the wood former. This is cheap insurance. You know what I mean if you've ever had a blind nut pop out when you're trying to get the screw started. That's a topic for the scale tip of the day...
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

03-05-2017 11:13 PM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Here's the latest: I figured out where the torque tube needed to go, then bonded the fiberglass donut and wood ring in place. This piece does not get bonded into the tail boom, it stays with the aluminum tail boom. After fitment, I used an old trick to hold the parts in place for bonding, I hot glued the donut to the tube. That way it stayed in place when I removed the aluminum boom from the fuse tail boom. The hot glue will be removed later after the adhesive cures. I also mocked up and fitted the wood section to the back of the mechs. This piece supports the connector that holds the removable tail boom in place. More on that later...
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

03-10-2017 10:02 PM
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Copter Doctor

rrProfessor

Enterprise/ft.rucker ,al- home of army aviation

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cool deal Barry, love the stang!

drive a rotary, fly a rotorcraft

03-10-2017 11:49 PM
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Heli143

Elite Veteran

Phenix City, AL

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Nice clean work as usual

Roy Mayoral

03-12-2017 11:55 PM
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doorman

rrProfessor

Sherwood, Arkansas

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Looking Good..

Coming along nicely!!!

Stan

AMA 2918-Team JR, Spin Blades, East Coast Scale Helicopter,Castle Creations

03-13-2017 12:24 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Thanks guys Here's the latest. I final fitted the boom to the fuse and inner adapter. Then bonded it all in place. This was quite the jigsaw puzzle and took many in/out fitments and bonding in sections. Don't try to do this installation in one shot, you'll be sorry...

The boom is removable for transportation and the inner boom is also removable for maintenance and inspection. I did a lot of head scratching and fit up, because the build plan leaves a lot to be desired. I actually bonded the wood ring on the wrong side of the tail adapter, because the instructions had 2 different depictions of where the part went. But it worked out fine. I'll add another ring to the opposite side when I bond it into the fuse.

I'm glad that I cut the tail section open, as this installation would have even more difficult if not impossible to get set up correctly, without that critical access. Notice the brass ring, this is what the outer threaded collar tightens against to cinch up the tail boom. This ring gets bonded to the inner boom. This part is a single point failure, if it lets go, the tail says goodbye amigo as it separates from the fuse. Good prep before bonding, Hysol adhesive and 3 hail Mary's and you're good to go. I'm toying with the idea of adding 2 extra screws under the boom as cheap insurance.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

03-13-2017 02:18 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Emile, glad you like the Mustang... It takes up a lot of my heli building time...

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

03-13-2017 02:48 AM
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coptercptn

Elite Veteran

Mesa AZ. USA

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Looking good Barry.. but yeah, I think I would go with the extra screws...
Even though the full size boom is only held on with 4 bolts....

Home of the "Sea Cobra".....

03-13-2017 04:06 AM
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PETER ROB

Elite Veteran

Devon UK

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Word of caution

Barry, the aluminium connector needs to be smeared with release grease, Copper slip, moly grease
They have a tendency to grab up if not lubricated
I have seen a few where that were not greased and almost impossible to use without some form of leverage
Chopper Jockey, took the tail of his 212, with an unsighted auto landing,mole grips would not budge the connector
Ended up cutting it off with a hacksaw, then replaced with new

As an aside, you have not replied, to my request for a confirmation of your address, the scale parts are awaiting dispatch
Peter R

03-13-2017 09:57 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Hi Peter, I'll catch up with my emails eventually... sorry, didn't mean to put you off. Thanks for the info, I had read in a couple of forums that you need to lube these threads. Makes perfect sense, because it's aluminum on aluminum, so it would tend to gall.

Jim, thanks for the opinion. I'm leaning towards the extra screws, just for cheap insurance.

So, I got the coupler bonded in today, it lined up nice and centered to the mechs tail drive. The boom is a nice flush fit and is centered on the centerline of the fuse. I used the carbon tail push rod tube for a sanity check when I was sanding the boom to fit. It fit in the end of the motor shaft like it was meant to be. You can see how the tail is like a hand in glove set up. It has mating parts that fit together very snug. Everything had to be sanded to fit, but it came out nicely.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

03-14-2017 04:22 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Got the primary tail drive shaft cut to size and installed today. Moving on to the secondary (aft) shaft tomorrow. I made up a cool little drill bar. It has a radius machined into it, which allows me to put a hole all the way through the tail boom 180 degrees apart. This was for the front bearing retainer in the tail boom. It has 2 holes 180 degrees apart.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

03-15-2017 02:41 AM
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goodhunting

Senior Heliman

Slovenia ... somewhere in Europe

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sure as heck helps if you have the correct tools and know how to use them
love your work.

Klem

03-15-2017 06:04 AM
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Peter Wales

Elite Veteran

Orlando Fl

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That's a neat trick Barry, I would have spent 1/2 hour setting up everything in the mill to get it dead center, and probably squished the tail boom at the same time.

Using your gizmo, you can do it on the pillar drill.

Peter Wales
http://scalehelicopters.org

03-15-2017 11:03 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Thanks guys
I'm glad you liked the custom drill bar Peter. It makes drilling through tubing a real breeze. It should be easy for you to machine up one of these. Or better yet, you can 3D print one and just install a #40 drill bushing in it. You can buy them from McMaster Carr. That set up will last for many years.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

03-17-2017 02:59 AM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Just boring stuff today, but this info may help someone else who builds this heli. I had to use a back spotface tool to remove a bunch of fiberglass and micro balloons from inside the stab, prior to bonding the blind nuts. So I just went one step further and made a nutplate from some .120 thick aluminum, drilled and tapped for 3mm bolts. Got it all bonded in place this evening. The one pic shows the inside of the stab where I removed the material. The nuts would not have sat flat without doing this first. The beauty of this is that the nut can't spin. A definite winner in my book.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

03-21-2017 03:26 AM
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Thumper217

Senior Heliman

Slidell, LA - USA

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Well, now I know what a back spotface tool is! Thanks for the education. I like the nut plate as well definitely better than blind nuts. Lots of good information in this thread.

Andrew

Thumper

03-21-2017 12:17 PM
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