Tethys tips?

SilicdyneTRF
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OK, just ordered some chopped glass and epoxy from USC, and some expanding foam and kwik links and stuff from PML. Definitely going to build this dual deploy capable, however for now I am not going with an e-bay, just a swivel taking its place. The build should start in a week or so, however long it takes to get the parts. Should be fun.
 
OK, if I could get ahold of an 8" long coupler (dont like cutting cardborad, for one, and for 2 it is 16.00 for a full length coupler from PML) i would cut my fincan off at 10.5", however i don't know if anyone makes a precut 8" coupler? LOC? DO they take custom orders?


Also, i need to know, that if i go with the 7, where to make the cut. The motor mount is 14" long, the mid cr is 6.5" up the tube, and I want the foremost CR at 14". Also, the motor mount starts flush with the airframe., so the CR would be 14" up. I also want the coupler sticking half out of the fincna and half in the fincan. I just came up with cut at 11", dont know if my logic works though. I'll ponder this for a bit more. One last item: I would like the coupler resting against the mid CR. (6.5" up) After thinking, 11 doesn't work, cause that isn't 3.5" from 6.5... Of course, i could just mount it 3.5 inches in the tube and cut at 11... I'd like it against the cr for simpleness purposes though.
 
Word of caution. You may find a LOC coupler may not fit inside your PML tube.
 
Thanks for the heads up. I'm gonna place another order with PML for some supplies i forgot, so I'll go with their 7" coupler and manage somehow.
 
I have also found that LOC couplers are very thin and flimsy. PML is definately the way to go.
 
Well....


I need to get some HPR cases to fly this thing, so I think I'll see if GLH has the PML couplers.
 
Got some stuff from PML today. Expanding foam, CRs, and a ubolt, finally a couple of bulkplates. The build should start tomorrow providing US composites is shipped on time.


EDIT: tested that foam a couple hours ago, wow. Mixed about 9ml in a NHP micing cup and it foamed WAY over. I like this stuff :D Then, i used the "juvenile" materials test and whacked it on the ground a few times. Weighs next to nothing too. Should make the tethys PLENTY strong, no need for glass. Also, does anyone have any CONs with chopped glass as a filler?


Thanks,

Blue
 
Originally posted by Blue_Ninja_150
Also, does anyone have any CONs with chopped glass as a filler?
Click to expand...

Yeah. It makes the epoxy almost impossible to sand. Practice making good fillets first! Milled fiber is super for strengthening epoxy! :)
 
Hmm. Just learned about epoxy (SOHK! SOHK!) and that USC epoxy DOES flash cure. Crud, what does the stuff smell like, i hope i don't have any on my hands....

Anyways, built the mmt for the tethys today. Duh easy.

More on the flash cure: I had miced a thin batch of epoxy for making the adpaters for the MMT, and let it sit for a while after making the adapters. I found a tube of graphite and wondered if it would be ok to use as a filler. Well, i picked up teh little cup and noticed it was pretty hot. I put the graphite in, but darn was that hot. I went in and got a margarine cup and put soem ice water in it. By teh time i got outside, the epoxy was hard. Good freakin' thing it didn't ignite.

Blue
 
Blue,
do yourself a favor and order or download the System Three Epoxy book. This is a fantastic reference on how to use epoxy.

Epoxy Book

I read things in that book about working with epoxy that I never imagined to ask...

Oh, and by hte way, post some construction pics. ;)
 
More mistakes and a few Qs... Last night, i made the adapters and set them urethane part down on the porch. No biggie, right? WRONG. The 38mm slot in the adapter is somewhat of a "well" however the 29mm is just pretty much a hole. I came out after a few hours to pick them up, and whammo the 29mm is stuck to the porch. I go down to get a hammer and chisel, but think that that would jack up the adapter, so i put them back. I put my shoes on and kicked it :( Now I need a new one... I need to also find some sort of drip pan as this epoxy i use with pumps, as teh pumps have maybe a 25 degree bend in the ends, and that drips epoxy EASY. I got a few drops on the wood floor :( and a few on the porch. Only thing i could think of was "don't make the same mistake twice". Otherwise, i'm gonna hold construction till I can order a coupler for teh fincan, probably around saturday.

Other than those few (KOFF! KOFF!) drawbacks to the pumps, i like them as opposed to holding a 2 pond bottle and trying to pour it accurately. I do wish however that USC would come out with minipumps. Do West systems pumps have a 38mm threaded part?

Blue
 
I let the batch of epoxy for the 54mm adapter sit maybe 15min- 1/2 hr before applying it to the tube cause I didn't want to use too much fiber in the epoxy so i could get teh plastic thing on the tube... Anyways, was waiting 30 minutes letting it sit too long and if it was how much of its strength would it lose?


Blue
 
Well, i did about half of teh cut yesterday at 10". Going to finish it pretty soon. I'm using my friend's laser guided chop saw with a plywood cutting blade. It has teeth every couple of millimeters.
 
Well, ig ot it cut for the most part, but i kinda botched teh job (Less than my initiator! That's a relief!) as the kerf on the blade was kinda weird. I have like 3 "steps" on each piece of tube, and they kinda fit together however I would like this to be even. Is there any way to perfectly sand this down, of am I stuck with this?


Blue
 
Hi. We finally got my dad's Tethys painted today, so I thought I'd take a few pics and post one... NO, the paint is not that glossy, it's just wet...:)
 
Will just taking a piece of sandpaper and scratching away at the tube work? or so I need to make a sanding block? Any advice is appreciated.
 
I should *hopefully* be ordering my motor cases and needed couplers today. Construction should resume around Saturday if Al's ships fast. For all other related construstion topics, I got the mid CR epoxied onto the 54mm motor tube. Yippee doo dah day.
 
It's been 2 years...



Lots of dumb excuses....



But it's nearly done!

I got so annoyed of epoxy getting all over, I pretty much quit using it for a couple years. Then I found some thicker Bob Smith stuff laying around, and got that out...

And now the Tethys just needs the fincan foamed, and it'll be totally ready for flight. Zipperless, DD capable, and other than that totally stock.

Sorry, no pics, I just wanted to get it DONE.

Blue
 
Originally posted by BlueNinja
It's been 2 years...



Lots of dumb excuses....



But it's nearly done!

I got so annoyed of epoxy getting all over, I pretty much quit using it for a couple years. Then I found some thicker Bob Smith stuff laying around, and got that out...

And now the Tethys just needs the fincan foamed, and it'll be totally ready for flight. Zipperless, DD capable, and other than that totally stock.

Sorry, no pics, I just wanted to get it DONE.

Blue
Click to expand...

Where are you with motor cases and reloads? ;)
 
Hah!

I've got the cases... I won't have the reloads until after I cert.

The cert's gonna be on a 38mm Onyx...

:eek:
 
Originally posted by BlueNinja
Hah!

I've got the cases... I won't have the reloads until after I cert.

The cert's gonna be on a 38mm Onyx...

:eek:
Click to expand...

HooWeee!

Good luck.... I hope you have a large landing zone to find it. ;)
 
Yep, Argonia's field should suffice.

A H128 will only give it about 2500 feet... Not too bad.

Then again, I'm thinking about getting a BeeLine which I'll put in there.
 
Originally posted by BlueNinja
Ok... so you use teh tape to pull it off?

Maybe, since I am using a PML retainer on this, a solution would be to pre drill the pilot holes for the woodinserts, then knot up a string and put it in one... Just a thought.
Click to expand...

Since you are using the PML retainer, just install that first, then when you install the motor mount, you can thread the retainer screws into the inserts, and use them to pull the ring back out.

Also, for future builds in which you want to use PML's retainer, just run to the local hardware store and pick up some 8-32 T nuts. I like them better than the brass inserts.
 
Well, I've built it zipperless, and the MMT has a 7" coupler on the front end of it, which keeps it centered without the need for 2 rings. I was looking at the aft end today, and realized that if I wanted an Aeropack retainer (that PML one looks futzy and not very strong. I think I'll save it for the Onyx.) I'd have to either get in there and grind the fin tabs down a bit, or leave the aft CR out.


Neither of these would be really preferable, of course.

The 54mm Aeropack requires a 1/2 inch overhang, which is all I've got... How can I make this work? Are slimlines the same?

Blue
 
slimlines are the same ( I am looking at one now) so your kinda SOL unless you can add an outer cupler and add a 1/2" section of MMT and put the CR over the coupler. all I could think of :p

thanx, Ben
 

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