Pre-production Twinn-Rexx build pictures

[sokal]

still wondering why fully articulating rotor heads arent used in rc

[v22chap]

grass hopper
Yep the blades are on right ,,but have done worse than that before ..... one on right and the other backwards .,,not on a rex but a larger bird with no markings on the blades ...that really causes a problem :rolling:happyd

Sokal

Love the V pix ,,,was that pax river or new river ,,, I have been to pax and meet the guys down there ...what a great group ,,,and what a neat bird . Hope I can get mine going again soon .:thumbup:

[sokal]

v22chap,
not sure its the one in North Carolina had to been atlease several 100 of them

[v22chap]

Sokal
And they all look alike too ,,It don't quite look like the one I was to ,,,but that has been 5 yrs ago and I wasn't looking at the building at all :):thumbup:
Thanks for more pix :thumbup:

[Gra55h0pper]

Finally, made a video... I realized my wife has a digital camera with the capability to make short video clips. I wasn't able to show forward flight at this point as it's taken in my backyard next to the swimming-pool... :D Wind was moderate. It shows: stable hover, pitch changes, yaw control and some "messing around" :D

http://www.youtube.com/watch?v=0aqQiEgKrMk

[v22chap]

Cool Grass hopper
That baby is really reved up .... ever put one in your pool ??:rolling:bawl:arggg:

[chinookmark]

That sounds awesome! You're blades make a really cool sound. What pinion/headspeed are you running?

[Gra55h0pper]

Yeah, it sounds pretty cool in the video. I need to check the head speed, but I don't think I have it up that high. I think it's more the sound bouncing off the walls of the house. As my wife made the video she was standing in the sliding glass door opening which may have distorted the sound somewhat.

[v22chap]

Ya ,,like the one I did in the garage ...

[Gra55h0pper]

We're getting there! I finished applying the decals (except for a Grasshopper which I still plan to put on the tail) and did another test-fit. See pictures! :D

[v22chap]

looks really good grass hopper

[MadDogDan]

h0pper,

I don't have my fuselage yet but will soon and was thinking about leaving the windows clear. Are the windows well defined? If they are, I was thinking of masking them off so they would be clear when I remove the tape after painting. Did you use the flybar limiter in the back? I have blow up the pictures in the video manual to 400% but still can't figure out how it is rigged up.

MadDog :thumbup:

[chinookmark]

MadDog,
The cockpit windows are well-difined, and are the round windows on the cabin door (not shown on Gra55h0pper's bird). The rest aren't molded, so you can easily do either airline style or military style.

[Gra55h0pper]

I don't have my fuselage yet but will soon and was thinking about leaving the windows clear

MadDog -- Only the cockpit windows and the round window in the door behind the cockpit are "defined". See: http://www.tech-mp.com/Twinn_Rexx/TRB1.jpg. I was happy about that as it made it easier to create a version with "civilian" windows. I used liquid masking film, "scribing" with an X-acto knife around a window template I created from a piece of spare body plastic. It worked out great but the whole procedure is a bit of a pain as you need to mask the windows before you can sand and prime the body which means you need to carefully sand around and in-between the windows. Also, as the liquid masking film is soluable in water, I couldn't just wash the whole fuse with water and soap in order to degrease it which I only realized after applying the masking film.

Given my learnings, I'd recommend the following "window procedure":
- after prep, wash the whole fuse with water and soap
- from this point on: wear gloves when handling the body (or at least: wash you're hands "all the time")
- apply liquid masking film
- scribe around the window template
- remove the liquid masking film around the windows
- sand the body staying away from the windows
- use a rag to remove any dust
- prime -> sand -> paint -> apply decals -> apply clear coat

The result looks great but it's a bit of work. The alternative (much less work) would be to simply apply the windows as printed decals.

Note that I used transparent black window paint on the inside of the windows which -in hindsight- I probably wouldn't do again as it made the windows a little too dark. Then again, I haven't looked at it in bright sunlight yet.

Can you post pictures of your progress? :)

[MadDogDan]

hopper,

I am not even finished with my build yet, in fact my TH2 mixer just came in today. I have done quite a bit of automotive painting and I was thinking of using auto grade masking tape and an Xacto to mask and trim the windows. For the porthole windows I was going to use circular price stickers in the proper diameter. They would then be pulled off when the paint dries. To reduce weight, I was going to use a lacquer that doesn't require primer or a clear coat. I am going to paint mine like the NASA helo and have Callie from "Callie Graphics" do all of the dry transfer decals. On another note: After looking at this mixer board, I am going to have to call Joe on Monday to get through the physical hook up of this thing.

MadDog

[Gra55h0pper]

To reduce weight, I was going to use a lacquer that doesn't require primer or a clear coat
Saving weight is always a good thing of course. I just weighed the body: 230g. This is before the clearcoat so I think I'll come out at 300g or so for the body with the enamel primer, paint and clearcoat.

The heli itself, without body, with battery weighed in at 1470g. This means the total AUW with the body will be around 1770g or so... I don't think mine will be the lightest around... :D

[Gra55h0pper]

Just did a quick hover test with an AUW of 1700g (added a second battery for additional weight). Definitely not the lightest heli I've ever flown :D but it hovers fine and still has additional power to climb. The motor, esc and battery didn't break a sweat. Also measured my headspeed (set as per the video I posted) @ 2300rpm... :shock:. Seems a bit on the high side so I dialed it down just a little, aiming for ~2100rpm.

Now I need a (fun)scale heli meet... :D

[MadDogDan]

h0pper,

Did you install the flybar limiter when you installed your fuselage? I have studied the pictures on Joe's web site and even blown them up to 400% but still cant see or figure out how he installed the limiter.

Any help you could provide would be greatly appreciated,
MadDog

[Gra55h0pper]

MadDog -- I have not installed the flybar limiter (part# TW-803) at this point. I'm not sure whether I'm going to as I don't really see the need. Even though the flybar doesn't clear the rear tower when at maximum deflection, I'm fairly sure it'll never actually hit it when the rotors are at speed. I know this from people installing a Trex 600 in a Funkey MD500 fuse; the same "problem" exists there. The deflection of the flybar when the rotors are turning at rpm, really is *that* big. That said, if you decide not to install the limiter, do so at your own risk though... :D

To install it, you need to drill a 1mm hole in the main rotor housing approx. 3 mm above the rectangular slot the flybar goes through (which allows the flybar to "pivot"). You then need to route the supplied wire through the flybar slot and the hole you just drilled and twist/solder the wire-ends into eachother. You can use the supplied wire sleeve on the wire in the flybar slot to give it a bit of a "bumper". Now when you try to pivot the flybar, the angle it can reach will be limited by the installed wire/sleeve and it cannot hit the rear tower anymore when the body is installed.

Note: those who do not intend to fly with the body can skip this step

[Gra55h0pper]

On another note: After looking at this mixer board, I am going to have to call Joe on Monday to get through the physical hook up of this thing.

MadDog -- Have you seen the wiring diagram pictured here: http://www.tech-mp.com/Twinn_Rexx_docs/TR_WD.PDF?
I suggest to study it closely.

Also, make sure to read the manual on the TH-2: http://www.tech-mp.com/tandem_sw.htm

When setting things up, it's very important that you do not have any CCPM mixing enabled in your transmitter. This means that when applying a cyclic control, only one of transmitted channels should change value. The reason for this is that the CCPM mixing is done by the TH-2 (for both rotors).

Just post your questions here if you have any :wink:

[Gra55h0pper]

Flew for the first time with the fuse today! She's a bit heavier of course, but flies great!!!

Couldn't resist to post a video :) :) :) :) :)

http://www.youtube.com/watch?v=AQA4E36chzI

[hoot]

INCREDIBLE! Awesome Beautiful!

[joe@tech-mp]

Great video ! Looks almost scale like in FF.

What do you have stabilizing the DCP ? Looked like some FRVI during FF to hover.


Joe

www.techmodelproducts.com

[v22chap]

Way to go Grass ... first full fuse flying that I have seen ... love the grasshopper on the tial tower :smokin::thumbup:

[chinookmark]

Awesome! It looks even better in the air!