Estes Lynx, time to do a build

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HHaase

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I've only seen a couple photos on here, and finally found one in my LHS, so I grabbed myself a Lynx today.
Before I get snapping photos and cutting tubing I'll give some initial thoughts from a quick browse of the package.

- Estes really dropped the ball on the insert card. The 3D rendered image doesn't really show how complex this little kit really is.

- This is a complex little kit, but looks like it's going to be a very fun build. I'd probably say making it Skill Level 3 was a bit optimistic.

- I was in a bit of a panic, the instruction sheet had three different languages, none of them were English. But a 2nd sheet was in the bag that does include words I can understand.

- Decals are interesting, but bland at the same time. I don't know if I'll go with the factory scheme. I mean, they're just plain white. But complex shaped. Weird.

- I'm worried about stability, but I'm not good enough to sim it in open rocket.


For right now, I'm flat out exhausted. So I'll start the actual build tomorrow.
 
Subscribed.

Wife has one to build and I'm considering a BT-60 w/ 29mm MMT upscale.
 
I've only seen a couple photos on here, and finally found one in my LHS, so I grabbed myself a Lynx today.
Before I get snapping photos and cutting tubing I'll give some initial thoughts from a quick browse of the package.

- Estes really dropped the ball on the insert card. The 3D rendered image doesn't really show how complex this little kit really is.

- This is a complex little kit, but looks like it's going to be a very fun build. I'd probably say making it Skill Level 3 was a bit optimistic.

- I was in a bit of a panic, the instruction sheet had three different languages, none of them were English. But a 2nd sheet was in the bag that does include words I can understand.

I too am a little disappointed in Estes kit literature lately. You're doing us all a service with this build thread. Subscribed.

- I'm worried about stability, but I'm not good enough to sim it in open rocket.

Well, you could always do the old-school swing test. I'm sure a little clay in the nose will make it behave, if it needs it.
 
Well, you could always do the old-school swing test. I'm sure a little clay in the nose will make it behave, if it needs it.

That's the plan, and the kit does include some clay also. Though it's not the CP/CG relation that I'm worried about. This has a very aircraft kind of wing profile to it. Bad alignment is my bigger concern.
I'm normally not a jig kinda guy, but this one may need it.

-Hans
 
Ok, lets start with the basic's, and what's in the kit. Doesn't look TOO bad now that I have it all laying out on the bench.
Sorry about the funky lighting here, my workbench is right in front of a window, and I haven't gotten around to putting curtains on there to help photography.

Nothing too odd for components, except that funky nose cone. Body tube is a BT-20, the two BT-5's are for side intake details.
Standard 13mm to BT-20 motor mount set, and a single sheet of balsa.

Instructions and warranty card were both included twice, each with three different languages on it. There's your insert card with the 3D rendered image.
The template sheet does seem a bit imposing, and decals are only printed in white with some black outlines to help you know where they are on the white backing sheet.
What I find really odd is that, as far as I know, it's only recently started shipping. But manufacture date on the bag was August 2014. Weird.

Next step, start building!

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Lets start, as per standard Estes, with the motor mount. Nothing odd just yet. Your basic centering rings on a tube.
Just watch your measurements on that lower centering ring, bottom edge of the ring needs to be 1/2" from the end of the tube due to additional details that are added later.
I'm just going by the instructions at this point, but am already seeing places I'd deviate if I built again. I'll explain when I get to that point.
One thing I don't recall seeing before is notching the lower centering ring to clear the retainer hook, but then again I don't build many 13mm motor mounts.

I've started using gorilla glue on most of my card stock motor mounts. I have a bottle that I want to use up, and this is a great application for it.
Due to the foaming action when it dries, I never use it where it would be visible. It works better if you dampen the parts before gluing. So I use a little terracotta bowl for water.

I wasn't happy with the quality of the motor mount kit to be honest. The centering rings were softer than usual, and really started to de-laminate badly. This made a poor fit for the rings onto the motor tube.
I ended up having to notch the yellow blocking ring to get it inside the motor tube. Any time I notched the rings they started to fall apart on me.

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While the motor mount dries, time to do some other pieces. So I am skipping around a bit compared to the instructions.

Marking the motor mount tube is, again, pretty standard. Wrap it, mark it, and head to a door frame.
Unfortunately, I ran the markings the full length BEFORE I removed the wrap, so I had to go back and fix it.

There is some fin assembly to do as well. Two pairs of park 'K', one pair of part 'G', and H/I combine to form the tail fin.
Don't be worried about mixing up parts 'K' and 'U'. They're dimensionally the same. Estes just changed the part number to keep people from doing too many pairs.
I did this on wax paper, and switched to Elmers wood glue.

Balsa quality is standard Estes, meaning it's very nice to work with. These pieces basically just fall off the balsa sheet. Very clean laser cutting with few retaining points.
Sanded pretty nice too along the edges. I won't be doing an airfoil profile though, nor papering the fins. Just too complex of an assembly to worry about those things.
Not to mention I like to keep some low altitude 13mm and 18mm rockets to fly in the back yard, I don't want too much altitude.

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Today is my day off, so I want to do some rocket building. I'm on a roll. So I'll keep on rolling.
Back to the motor mount. For this step, you'll need the little ring from the template sheet, and these little guys on the balsa sheet.
Estes says to mark the motor mount tube at each line, then remove the ring. Honestly, I found it easier to just glue the ring down and leave it there.
Then I added the motor mount strakes as per the markings.

If I were to do this again, I'd probably add the strakes FIRST, then install the centering rings. I must have slipped or something during my measurement, as I have a bit of a gap between the strakes and the ring.
Still going to look good. So I'm not too worried about it.

I also deviated from Estes instructions on which fins to add first. They said to add the top fin, I decided to do the bottom wing first. Makes it more stable laying on the bench, and less chance of getting things out of whack. Get used to looking at the butt of this rocket, seems like every step from here on has a rear profile to look at.

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Still not too bad at this stage. Added the top wings. Need to add a bit of a bevel in there along the top edge. The trick though is aligning them even with each other, and even with the tips of the lower wing. Fairly easy. Then take another look at the rear profile to check it's all straight.

Adding the vertical wingtips started getting a bit tricky. If you have a sanding block, use it to make the ends of the main wings square and parallel. It doesn't help that at this point you have a lot of oddball angles playing against each other, and it's hard to see if you're plumb and square. Remember to put them at a right angle to the lower wing, and only look at that. If you try to align them with the central fin, the optical illusions of all the angles is going to make you think it's crooked.

By a comparison, the canards are easy. It's really starting to take shape here, and I'm loving the lines of the build. Until the next step, when you start cursing it.

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Now we get to the intakes. I completely goofed them up initially, so lets skip a couple photos of things gone wrong.
DO NOT CUT OUT THE OVAL SHAPE from the template (guess what I did?). Take your template, as a rectangular shape, and wrap it around one of the BT-5's.
Chuck in a fresh #11 blade, and follow along to cut it out. Taking your time, you can definitely get both intakes out of a single BT-5, leaving one for a later project.
I found it helped to re-tape every so often, to keep things together.

But gluing them on turned into a nightmare. I'm just not used to doing this kind of work with cardboard tubes, so my glue joints ended up awful.
So did the angles of the cuts on the tube. Really hard to keep them even compared to each other too. So it's time to break out the wood filler.

Next update will be a while, I've got a lot of sanding, shaping, filling, sanding, shaping, filling... etc.

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It's all fun and games, until you get sanding dust in your eye.

-Hans
 
Looks like a fun build, for sure. I agree though....doesn't look like a Skill Level 3.

Anxiously awaiting the rest of your build...
 
I bought the Lynx and Scorpion kits for my 10 year old, these might be a little challenging, he built both the Crossfire and Amazon in the TandemX kit himself. so far he did the motor mount for the Lynx, very helpful to see your build thread here.

When cutting the air intakes, not sure if it would help to poke holes along the line with a needle or other awl type of tool through the paper and the tube, then connect the dots with the knife. You can lightly sand the edges of the tube to smooth it out, and tack it down in a few spots, let dry, then give it a generous fillet of glue to make the seam look smooth. that looks like one of the more challenging parts of the build.
 
It's been a long time since I've done any detail work like the side intakes. With some practice I'm sure they would be a lot easier.
I'll have more photos tonight hopefully. Lots of filling and sanding going on here.

-Hans
 
...
When cutting the air intakes, not sure if it would help to poke holes along the line with a needle or other awl type of tool through the paper and the tube, then connect the dots with the knife. ...

Great tip GlenP. Make the long run a series of shorter runs.

It's been a long time since I've done any detail work like the side intakes. With some practice I'm sure they would be a lot easier.
I'll have more photos tonight hopefully. Lots of filling and sanding going on here.

-Hans

Keep up the good work Hans and thanks for documenting this. Filler has been my friend on many builds. :eek:
 
I bought the Lynx and Scorpion kits for my 10 year old, these might be a little challenging, he built both the Crossfire and Amazon in the TandemX kit himself. so far he did the motor mount for the Lynx, very helpful to see your build thread here.

When cutting the air intakes, not sure if it would help to poke holes along the line with a needle or other awl type of tool through the paper and the tube, then connect the dots with the knife. You can lightly sand the edges of the tube to smooth it out, and tack it down in a few spots, let dry, then give it a generous fillet of glue to make the seam look smooth. that looks like one of the more challenging parts of the build.

I used a pin to mark the intakes before cutting.
The only disadvantage, it took more sanding than normal to sand down and remove the pin holes.
Usually I'll wrap the main tube with 400 grit and sand tubes to fit the contour of the outside tube wall.

Your ten year old might need some help cutting the intakes. BT-5 tubes get a little floppy after cutting them out.
 
...Usually I'll wrap the main tube with 400 grit and sand tubes to fit the contour of the outside tube wall...

this is a great idea, you could potentially hand sand a bevel to the cut edge so that the outer visible edge makes contact for a neater appearance, but using the contour of the mating body tube itself should give you the bevel that you need on the inside edge of the intake tube, and give a good glueing surface too.
 
Ok, more progress today (and yesterday, I got too lazy to resize and upload)
First applications of filler, and adding some of the last exterior details.
Nothing fancy, just lots of sanding. Lots of filler.

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Then after the first shot of primer/filler. I'm not going to go aggressive on removing the primer in this case, I'll leave it a bit on the heavy side.
I fly my LPR's in my back yard, so a bit more weight will keep it low, which will keep it in the yard.
A lot better than I expected at this stage. A bit of voids along the bottom, and a lump look to the top side of the port intake are my only major spots to worry about.
I'll clean those up, give it a quick sanding with some 220 grit along the rest of the primer, and see how she looks.

I'm thinking of a 60's era target drone scheme for this one. Just not sure if I'll stick with red, or grab some orange.

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A few little things to sand down again, but otherwise I've decided to move forward to final finishing. Not much left, really. Launch lugs are now attached, one more coat of primer to give an even base, and two coats of Rustoleum 2X 'Real Orange'. I don't usually chase down perfectly smooth fins, and this one is too complex anyway. I'd never finish.

Then some fairly complex masking, and black trim in appropriate places.
I'm itchy to get this one done, as I have a Scion right behind it to get started on. And I also ordered a Raven3 and 38mm av-bay for my Painkiller Micro.

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Something about this build kept making me think of the old Ryan Firebee. Orange with black, and some markings out of my pile 'o decals.
I think I can call this build finished at this point. (Technically I still need to clear coat it, but that's not photo worthy).

I may go back and touch up some of the small oversprays in the masking if I feel so inclined, but I build flyers not show queens.
So I may just fly it until she falls apart. Now to get some 13mm motors and let 'er rip!

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Whooooooo boy this sucker ain't for windy days. Had to track it 100 yards into the neighbors beans. Arced over, and then drifted forever on the chute.

[video=youtube_share;wuQgT0wF_8E]https://youtu.be/wuQgT0wF_8E[/video]
 
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