Workin on a Micro T3 Snarky

[Micromeister]

I've been a bit side tracked with Family and Health issues of late but have been doing a little on bringing a T3 Snarky into built condition.
With all the people in the house, Extra babies, Dogs and Cats too boot I've been going very slowly with this build, putting everything away each evening trying to keep little finger and teeth off the balsa and basswood LOL!!
Sorry no Photos as yet..have them still in the camera but I can share the MMWW One-page Plan that I'm building from if any are interested.
I'll try to up-load it as a .pdf.

Progress photos to follow.

Ps: CP CG Locations added 08-24-11
Ps: Dorsal Scoop Fin Added 09-08-11

[dixontj93060]

Looking forward to seeing this one!

[KHamel]

This should be good! I have a full size Snarky, an MMXX Snarky is a very cool idea!

[Micromeister]

As always we start by building a T2+ to T3 Micro Motor mount with 90lb Kevlar shockline around the forward centering ring. with this model I started with 40" of Kevlar, a couple inches will be cutoff when tied into an overhand loop to be CA/epoxied into the hollowed out NCB-3AD Flis Balsa nosecone. generally 30-36" of 50-90llb Kevlar shock line has worked out best serviving 20-25 flights average.

Over the weekend did a bit more work on the Micro Snarky and managed to caption the build photos. First five show the typical T2+/T3 Micro MMT parts and assembly.

[blackjack2564]

You got my attention with this one!

I'll definitely be watching. All ready saved the PDF for the fall slowdown.

[Micromeister]

You got my attention with this one!

I'll definitely be watching. All ready saved the PDF for the fall slowdown.

Should be a fun little build...I think finishing will take much more time then the building.

[Micromeister]

These next 5 pics show the 90lb twisted Kevlar line i've been using now for about 4years. the Spool came from www.thethreadexchange.com a great place to get bulk kevlar and other lines and thread. Sorry the do not sell tubular or breaded Kevlar which would be a good be limper but this twisted line has worked out fine for me with 25+ flights typical before replacing is needed. Thinner lighter pound test Kevlar lines can be used but you will be replacing them quite a bit more often.

Passing the tied on shockline back out through the motor mount, securing it with by friction fitting a hardwood down makes installing the motor mount a lot easier. After applying a thin coating of White glue to the inside of the T3 main body, Keep the dowel set as close to the motor block as practical while pushing (In a single smooth forward motion) the MMT until it seats the rear Centering ring flush with the end of the T3 Body tube. This should leave 1/8 to 3/16" of Motor mount tube extending from the rear of the model which helps greatly with extra external taping the motor in addition to the normal internal friction tape. I've only lost one motor after switching to this tape scheme.

[Scotty Dog]

Snarkyro ,Like embryo,micro.?????? Anywhoo- good luck. Looking forward to build pics. Good Luck with this one.

[Micromeister]

Now comes the fun parts.
The second shorter T3 lower tube gets a 35° forward and 15° aft angled cut before removing a .281" slice from the top. There are a few other ways to accomplish this but I decided I'd go with the most conservative using computer paper wraps, a sharpie marker and Stropped #11 X-acto blade to knife out the curves and spine over an internal mandrel to keep the edges as clean and crisp as possible. Hand knifeing around small tubes takes a little patients and close attention keeping the knife on top and equal pressure as you slowly turn the tube and mandrel combination always trying to work the blade toward you.

I used Plate Glass Plates to mark the parallel lines along the top centerline of the Ramjet T3 tube and the alignment lines for the wings, elevators, vertical tail and glue lines for the ramjet tube along the Main body T3. While drawing these lines I kept the tubes on T3 internal mandrels to ensure the parallel lines stayed true and consistant.
By setting the Ramjet tube against a 3/8" piece of Plate glass that was sitting on another 1/4" plate running the strop sharpened X-Acto knife along the glass edge set at one of the parallel cutting lines made quick work of removing the section.

I marked and applied a bit of yellow glue along both sides on the attachment lines, the set the Ram tube in place.

Fliskits NCB-3AD is just about a perfect match for this model. A little later I'll hollow it out with a small Dremel end cutter and install an overhand knotted loop of 90lb kevlar set in a small amount of CA. this well be topped with whatever Noseweight is needed and a bit of 5 minute epoxy.

[Micromeister]

Decided to go with .032" Basswood for the wings and such some of which have some fairly small spans across the grain. To help strengthen these points I went with white wrapping tissue.
After tracing the fin and wing patterns onto cardstock I cut these out to use as templates making sure to adjust the grain with the leading edge of each part. Once all 5 pieces were nested nicely on a small strip of 1/32" basswood I coated on side with a thin layer of white glue and carefully and smoothly applied it to the edge of the tissue. then rubbed white glue on the remaining side and flipped the piece onto the tissue while maintaining tension to keep everything flat and smooth. rubbed down both sides under a piece of wax paper and sandwiched the slab between to pieces of 1/4" plate glass weighted with a couple books for the night.
Next day the laminate was dry and strong. Using my X-acto #11 and straight edge I cutout the parts then sanded the leading and tailing edges round.
These parts are just a bit to small to use my attachment jig so I reverted the reckless eyeball method attaching and aligning the 5 pieces as best I could. Using my assemble jig does help a good bit as I can attach the parts in the horizontal position then set the jig in the vertical while the glue dries.

After the glue had a day or two to completely dry, thin 5 minute epoxy fillets were added to all the joints.
While the epoxy was still soft 2 small pieces of Fliskit clear Launch lug were installed under one wing. The assemble was set aside to dry.

While the epoxy cured a 3/32" end cutter was installed in a dremel and the Fliskit NCB-3AD Nosecone was hollowed out about 3/4 of the way down. the opening is just about 1/4". a Loop of 90lb kevlar is tied about 1-1/4" long with an simple overhand knot. the ends are trimmed close to the knot so it sets dead in the bottom of the hollowed cone. a few drops of med CA are all thats needed to fasten the loop in place at this point. After finishing and such we'll balance the model adding whatever Nose weight is needed followed by a few drops of epoxy to lock it in permanently.

Once the Epoxy fillets completely cures I'll give the entire model a light sanding with 240girt paper and we'll be ready for first coats of cheapy primer.

[Micromeister]

Well it's been POURING for the last few days around here. I've applied the first 3 unsanded coats of cheapy primer now we'll wait until the nose test tells me it's time to 240 rough sand. could be a day or two...could be a week depending on the humidity.

[dixontj93060]

Looking great!

[dragon_rider10]

Well it's been POURING for the last few days around here. I've applied the first 3 unsanded coats of cheapy primer now we'll wait until the nose test tells me it's time to 240 rough sand. could be a day or two...could be a week depending on the humidity.

UBER-awesome!

[[POW]Eagle159]

NICE, looks pretty heavy for the MMX... Final specs?

[Micromeister]

Eagle159;228308']NICE, looks pretty heavy for the MMX... Final specs?

it's a little early for final specs but as it is with 3coats of primer and 1/2" x 12" teflon streamer she weighs in at 6.1grams giving a LOwt of about 7.2grams.
By the time I'm done sanding and filling,Paint, decals and Future I imagine the model will be in that range. shooting for the ideal 7-8gram mass I think we're pretty much on target.

Not sure of how much additional nose weight will be required at this point I'm still looking for a CG location from someone who has a standard size Snarky.

[KHamel]

it's a little early for final specs but as it is with 3coats of primer and 1/2" x 12" teflon streamer she weighs in at 6.1grams giving a LOwt of about 7.2grams.
By the time I'm done sanding and filling,Paint, decals and Future I imagine the model will be in that range. shooting for the ideal 7-8gram mass I think we're pretty much on target.

Not sure of how much additional nose weight will be required at this point I'm still looking for a CG location from someone who has a standard size Snarky.

I pulled up the Snarky Rsim file on my other computer and these are the results I have:

CP 21.82" from the tip of the nose

CG 18.75" with an AT F24-7 loaded I have flown mine on this motor and had a stable flight.

Leaving a margin of 1.39. I hope this helps.

[Micromeister]

I pulled up the Snarky Rsim file on my other computer and these are the results I have:

CP 21.82" from the tip of the nose

CG 18.75" with an AT F24-7 loaded I have flown mine on this motor and had a stable flight.

Leaving a margin of 1.39. I hope this helps.



Sure does Keith thanks a bunch!

[Micromeister]

Well if the laborday weekend had to be Rainy off and on. It wasn't a completely wasted. the Better 2/3rds and I got to spend some time on our respective hobbies. She in the Ceramic shop, and me with a couple Micro models including doing some finish work on the T3 Sharky.
Spent a decent amount of time in prep work on the 2nd primer coat. Krylon Gloss white base coat and some masking to paint the Scoop Gunship Grey (wanted a lighter Ghost grey) but didn't have any in the house...
On Monday I printed the decals, getting them fixatif coated, hopefully will be able to UV clear them tonight if the humidity isn't to high?

Still have some touch up brush work to do on the Gunship grey on the outside of the scoop as will as painting inside some of the scoop Red..which should be fun.

[Micromeister]

I didn't like how dark the gunship grey left the intake scoop is I decided to sand it off and try a lighter Aircraft Grey. I'll brush this color on rather then remask everything again. should be fine.
While I was at it I installed the forgotten intake fin using .005" waferglass to keep both thickness and mass to minimum. Not sure how much this little fin will help but since there is one on the larger models we're including it in this downscale.
Installed the 1/2" x 9" green teflon streamer, tied on the Nose cone a placed it on the scale after the future had a chance to dry. Ewt.= 7.2g.

Adding a motor our LOWt should be right at 8.3g

Sims to fly without any additional nose weight. even with the hollowed Nosecone the CG seems to be in the proper "Scaled" place...We'll see.

With a little luck I'll get to launch this one sometime Saturday.

Sorry for the slightly out of focus photos I'm not sure why it does this when I'm trying to get close ups....

[KHamel]

John looks great as always! Looking forward to the launch report.

[Micromeister]

Well I finally got the T3 snarky out of the Rain and into the skys....Almost.
As suspected it still needs a bit of Nose weight. other then a quick tumble during flight...Sorry I missing the in-flight pic.. it's a fine little beasty:)
Didn't have any clay or shot with me...it's been a long spell since the last launch...Lord we're tired of RAIN! Anyway I'll be adding about 1/2g of #9 shot to the NC this evening.

[[POW]Eagle159]

I like how big your rocket is compared to the others.

What is that green one that looks like a missile? scratch built?

I like them both.

[Micromeister]

Yes it's a scratch built fantasy semi-Scale Soviet ICBM thingy by the guy hooking it up Alex our club VP.