Tango's Crossfire ISX - Stock Build

[TangoJuliet]

My girlfriend asked me not to buy any more kits until I'd built the small stock pile of kits at home, and I agreed.

However, it was another slow weekend at work and I forgot to bring one of those kits with me, so a Hobby Lobby 40% Off Coupon twisted my arm and forced me to buy another kit.

That's my story, and I'm sticking to it. 😁

I really like the look of this little kit and I think it begs for an upscale, but this will be the stock kit build, and it starts like all the others, with the motor mount.


The Thrust Ring is positioned with the use of one of those short yellow telescopic tubes, and measurements.


Measurements locate the Centering Rings also.


While the glue was drying on that, I separated the Nose Cone from the Nozzle Flare. I don't have a razor saw at work, so this was carefully done with a #11 Xacto blade.

 

[Nytrunner]

Major props to you and your patience for using an Xacto to liberate that nozzle. Figuring the plastic was soft, I tried for about ten minutes before rage-grabbing a hacksaw.
Crossfire's are fun. They do have a tendency to disappear on C's unless you use a streamer or spill hole.

 

[Fred Garvin]

?....They do have a tendency to disappear on C's unless you use a streamer or spill hole.

Uh huh....I was gonna warn you too....great little flier....but it can pull a vanishing act on ya......

 

[TangoJuliet]

Major props to you and your patience for using an Xacto to liberate that nozzle. Figuring the plastic was soft, I tried for about ten minutes before rage-grabbing a hacksaw.
Crossfire's are fun. They do have a tendency to disappear on C's unless you use a streamer or spill hole.

Mine must have been softer. It wasn't as difficult as I expected it to be. In fact, I was so worried that it was going to harder, that I almost waited to do that at home with my Zona saw.

I'm leaning toward using a Mylar streamer. I recently bought a large roll of 1 mil Mylar Window Film on Amazon to make my own streamers.

 

[TangoJuliet]

The next step was to locate a center line on the BT between two fins for placement of the launch lug. Oddly, this set of instructions did not come with a paper marking guide for this. Presumably because the BT is pre-cut for through-the-wall fin attachment, so there's no need to mark for the fins. I suppose I could have just eye-balled the center, but I devised another way to locate it. I wrapped a Post-it Note around the BT at the fin slots and marked the edges. Then I removed it and measured to find the center between the two points. Once that was done, I could put it back on the BT and transfer the center mark, then use a door jam to extend the line. Voila!

 

[TangoJuliet]

The Nozzle Flare needs to be relieved for the engine retainer clip. This can also be a bit touch and go using a #11 blade, but working slowly and lightly scoring the plastic over and over will get the required results. I cleaned up the cut with a little 400 grit sandpaper.

 

[mrichhcirm]

Streamers are your friends with this bird, especially on C motors. Also recommend you reinforce the little strakes (if not the entire fins) with paper skins and glue to keep them from splitting along grain.

 

[TangoJuliet]

I don't paper fins. Up to this point I've been applying thinned wood filler, but I've been doing it after the fins were installed. This time I thought I would try a bit different approach.

I decided to apply the filler to the sheet of balsa before removing the fins and tabs (someone else referred to them as mini Millenium Falcons). It worked out ok, but I almost lost sight of the laser cut pieces afterward. At home I prefer to use Aero-Gloss Balsa Filler, but it's too stinky for use at work. In the end, I didn't get the wood grain filled as well as I'd hoped for. I also didn't bother to fill the seams on the BT. They looked really tight to me and I figured I could hide them with paint.

 

[K'Tesh]

What? TopRamen hasn't weighed in on this? I'll be watching this. op:

 

[TangoJuliet]

Papering fins isn't even something I've tried to do yet, and some BT seams are admittedly worse than others, so I pick and choose. Ultimately though, I'm lazy. 😁

I have a Fat Boy I built over 15 years ago, before I'd ever even heard of filling seams, and good Lord, those seams could hold a half-dollar on edge! But in a way, it's nice to have as a comparison model to show what extra effort and attention to details can do. I've been accused of being a perfectionist and OCD by coworkers, but my rockets prove that I'm not.

 

[Nytrunner]

Streamers are your friends with this bird, especially on C motors. Also recommend you reinforce the little strakes (if not the entire fins) with paper skins and glue to keep them from splitting along grain.

What kind of punishment do you subject your Crossfires to? I've never had the fins even hint at cracking.

 

[mrichhcirm]

Ummm....landing? (Esp with streamer...you either risk breakage or loss--i opt for breakage.) My bird has been flown a lot as it's my favorite. I've repaired and repainted often

 

[TangoJuliet]

And then came glueing on the fins. I like the TTW fin attachment, but I did notice the the BT bowed out slightly in between each fin. Not a big deal, and it kind of creates a neat shape to the BT in that area.



And the fin tabs...



The shrinkage of the Tite-Bond II left a bit of a gap between the trailing edge of one fin and its associated tab. My fat little fingers found it hard to swipe in some glue and get a good fillet, so I used a coffee stirrer cut at an angle to place and draw the glue where I needed it.

 

[Nytrunner]

I had the exact same bulging on Goldfinger II, but I thought it was the wrinkled tube that came with it.

Is TB II lighter than Elmer's?

 

[Zebedee]

I've flown everything from 1/2A to M motors and this model is still one of my favorites. I've built 3 and have 1 of those left (time for another I guess).

I agree with reinforcing the strakes with paper because they seem to snap off pretty easily.
I second the streamer idea for launching on a C.

I'm not brave enough to build a D powered model like TopRamen...

 

[TangoJuliet]

I had the exact same bulging on Goldfinger II, but I thought it was the wrinkled tube that came with it.

The bulging is most certainly a result of cutting away the BT for the TTW fins. A shorter cut wouldn't be so bad, but the longer cuts affect the integrity of the spiral winding. Once the fins are glued in and filleted, the integrity is restored, but there is still a bulge. One way to eliminate any bulge would be to install a centering ring in the middle of the cut area and glue the BT down to it, then notch the fins to go over it.

Is TB II lighter than Elmer's?

I don't really know. I've used TBII for years in my R/C airplane builds. It's my go to glue for most things. CA and Epoxy are only used where necessary for specific applications.

 

[TangoJuliet]

I have an admission to make... This build took place two weekends ago while at work, and this is what it looked like the following Wednesday before I left work with it for my week off.


When I got home it was time to apply paint; deciding to stay with the stock color scheme.


My can of Testors Dark Red was nearing its end and I got a bit of a mottled coverage in its opaqueness. I decided I could live with it... This time.


I'm really not a fan of the peel and stick decals. I much prefer water slides. I almost decided to try my hand at masking and painting the markings instead of using stickers, but given that I wasn't making the extra effort on the red paint, I saw no point in making the extra effort for markings. In the end, it looks perfectly acceptable from 2' away!



I'm not sure how long it will be before I can launch it, or any of the half dozen rockets I've built lately, because we are under a statewide burn ban. We haven't had any significant rain in over two months! I hate to complain about the absolutely gorgeous weather we've had, but we really do need rain.

Thanks for tuning in. I hope someone gets something from this.

 

[TopRamen]

What? TopRamen hasn't weighed in on this? I'll be watching this. op:

I had not seen it yet.
I'm here now though.
I hate that I have been preoccupied with fixing my home, but it will pay off in the end.
I do love a Crossfire ISX, and they really can perform in flight, so I will subscribe to this thread and make a point of seeing the progress.
It is one of my top 5 "Most Perfect Rockets Ever".

[video=youtube;5X_KgWGQ5z8]https://www.youtube.com/watch?v=5X_KgWGQ5z8[/video]

Definitely a Streamer rocket, and if you are brave enough for a chute, you might want some more kits.

 

[TangoJuliet]

... so I will subscribe to this thread and make a point of seeing the progress.

Better late than never, but I'm afraid you came in at the end, except for the maiden flight, which may be a while unless we get some serious rain soon.

 

[TopRamen]

Better late than never, but I'm afraid you came in at the end, except for the maiden flight, which may be a while unless we get some serious rain soon.

She looks great! Very nice job!
Please do get a vid' of her maiden flight!
I'm going to fly a Crossfire today in my yard if I get a chance.

 

[TangoJuliet]

I'll surely try. I've got a Sony Action Cam that I can mount near the launch pad when the time comes.

In my mind I've been toying with an idea that will allow the camera to pivot from horizontal, looking at the rocket on the launch pad, to near vertical as the rocket leaves the pad. I'm thinking a mount that keeps it just off the tipping point until the blast of air from the ignition event hits it, or if necessary, something spring loaded and held horizontal by a burn thread.

 

[Nytrunner]

Better late than never, but I'm afraid you came in at the end, except for the maiden flight, which may be a while unless we get some serious rain soon.

Ah yes! A stealth build! I've got one of those in progress for my Scion->Leviathan. Didn't start the thread because I realized I wanted some slight modifications and needed to order some odds and ends.

 

[TangoJuliet]

Yeah, something like that. I was going to start a Big Daddy this weekend - another week at work - but then decided I also wanted to make some minor changes to it and didn't have the materials here at work to do it. (Lose the Engine Thrust Ring, replace the Estes Shock Cord with Kevlar Cord and Elastic, and cut the NC shoulder per other mods)