Pic of Spectra G tail section

[Ray Fernandez]

Does anyone have a pic of the tail section of a Spectra G? Need to see the clamp that holds the tailrotor housing.

Thanks

[DavidH]

The clamp will be the same as the other X-cell helis that use the closed gear box. That is the boxes that have 3 mounting lugs.The Spectra comes with the closed CNC gear box.
If it is the new CNC closed box that has the four mounting lugs. Then it will use the same two piece clamp as the open tail box and mount the same.

David

[Ray Fernandez]

Thank David.

I was just wondering about the clamp. I recently bought Nolan's Spectra G and noticed that the tail section is a Extreme tailrotor housing and not the four mounting lug as in the diagram for the Spectra.

Would this be okay to use without any problems?

[carey shurley]

so is it a closed t/r gearbox? is the tail boom clamp one piece with a screw through the top of it or is it a two piece clamp that connects to the transmission with two bolts through the sides of the boom into the transmission

[DavidH]

Ray,
I am guessing you have the closed gear box that has the 3 mounting lugs then. The proper clamp for that for box should be one piece that goes around the boom. On the side opposite of the mounting lugs for the vertical tail fin. There will be split and bolt hole, a bolt and nut go here to clamp the clamp to the boom. Then a screw would go in the top of the clamp thru the boom. This will be a small sheet metal screw. The gear box is bolted to the clamp with 3 3mm sheet metal screws.

This drawing on Ricks site should give you an idea what I am explaining above. This is plastic gear box, but older style 3 lug CNC box is the same.

http://www.ronlund.com/images/plans/xlse/tailboom.jpg

David

[Ray Fernandez]

That's the piece I have (#0683) on the closed tail gearbox.

[carey shurley]

most of us flew that clamp arrangement for years both on glow and gasoline models. As long as you make sure that screw goes through the clamp, the boom and goes into the indentation on the top of the transmission, it will be fine.

When you need to replace those parts, you may want to update all of that to the new setup.

[Ray Fernandez]

Thanks Carey. I figured as much, as my older 1005 helis had the same thing. I just thought that the newer MA Gassers had some "special" thing that required a newer tailrotor gear case fastner.

[carey shurley]

when the spectra was first released, it had the current open t/r gearcase on it. A number of folks had problems with the output shaft breaking inside the case bearing near the output gear with obvious results. The reason behind this is not fully understood, but it is believed that it is related to engine vibration, especially when the motors are new or out of tune. Anyway, MA offered to replace all of these with the std closed case at no cost and did so for well over a year. Its basically the same case you have with 4 mount lugs instead of 3 and threaded holes on each side for bolts that go through the boom. All of the shafts, gears, etc are all the same.

To be fair, the new setup is secured to the boom far better than the old setup but if you put it on correctly you won't have any problems with what you have.

[Dr.Ben]

An extra measure of security with the older style clamp can be had by roughening up the end of the boom where the clamp lies and epoxying the clamp to the end of the boom. Over time, the plastic in the older clamp can flow/stretch enough that the clamp can be fully tightened, yet the gearbox will get lose. The screw will wallow out the hole through the boom when the clamp starts to wiggle. As long as the clamp is fixtured to the boom the the box is fixtured to the clamp, the box can't and won't go anywhere. Then the screw is just added security.

BTW, if you crash hard enough to kill a boom, the clamp being epoxied to the boom is of no financial concern. They're cheap.

Ben Minor

[rbort]

Instead of epoxy, try masking tape. I put a layer of tape under the clamp to thicken the boom and the clamp will bite down so good on the tape its not going anywhere.

If you are careful you can hide the tape below the clamp and not even know its there. Usually a piece one and a half times around the boom is just about perfect. That equates to less than 6 inches.

-=>Raja.

[lep1933]

I'm working on the installation of my closed tail gearbox and when I go to put the box onto the tail boom and engage the torque tube, the two holes 180 degrees from each other on the boom that the clamp goes over are not aligning with the gearbox. It's as if the tail boom is a fraction of an inch too long and there is absolutely no way to force the gear box on any further to get the correct alignment. I'm only getting the gearbox holes to come up about halfway in alignment to the holes. I'd surely cross thread the gearbox holes if I tried to screw in the required M3X8 socket head screws.

What should I do? Should I try to shim the end of the tail boom a bit (and how the heck would I do that evenly??) or should I elongate the holes in the boom with a Dremel tool? The instructions indicate there should be a 0.013" bit of the tail boom sticking out from the clamp, but if I try to sand or otherwise remove it, that will disappear. Maybe that extra tail boom bit was to accomdate for the shim (part #123-88) and since the pictures for the closed gearbox don't include the shim, it isn't needed, but this extra trim off the end of the tail boom is necessary?

I'm new at this and before I ruin my tail boom, I could use some suggestions. This is the first problem I've had and with already being on step #9 with nothing but great things to say about the quality of this model assembly, I'm hoping there's a simple fix.

Thanks to all for your help. I love this forum!

Lep

[carey shurley]

I just rebuilt a spectra tail boom with the closed tail box

I needed to slightly elongate the two side holes on the end towards the t/r gear box. Its easy to do with an xacto knife (just be careful). A very small amount of material needs to be removed. The boom clamp goes flush to the end of the boom which should align the clamp holes with the transmission threads. when you remove the material, it should all line up.

There was a revision to the hole position on the t/r gearbox and I don't think its made it to the jig used for drilling those holes.

Does this make sense?

[lep1933]

Thank you carey for the quick response. That does make sense. I was just worried that there would be some kind of play introduced in the securing of the clamp and gearbox assembly. I suppose the more I look at it, those two holes are not supporting the assembly, but rather they are preventing rotation of it around the boom and causing the tail to move out of its perpendicular alignment to the main rotor.

Also, removal of the tail boom material in elongating the holes sounds like it could be difficult with an exacto, but I suppose being careful is the key and not taking too much out is most important.

I'll give it a try. Thank you so much once again.

Lep

[carey shurley]

you're correct, the holes prevent the assembly from turning and are insurance that it can't fly off. Once you get it all bolted together, its not going anywhere