Ultimate Wildman questions

[boatgeek]

Thank you for the insight. I definitely haven't settled on computers yet and I'm sure my wife would appreciate a cheaper price point. I have very little experience in dual deployment and have never run backups. I am working on building a smaller rocket out of spare components to serve as sort of a test bed to help me be more proficient in it. The only electronic deployment I have done used a single old g-wiz lc 400 I had from highschool when I was doing the TARC. I motor deployed my drouge and used the g wiz to blow the main and it could only do one of two altitudes 400 feet or apogee it worked for my level two certification a few weeks ago inspite of being 15 years old lol but I need something much more complex for this project

One thing I really like about the Quark/RRC2+ is that they both program really easily with three jumpers/DIP switches. You can do that before you get to the field, so there's one less thing to do on site. They have somewhat fewer options in terms of apogee delay and main altitude, but I think the ease of programming makes up for that in a redundant setup.

 

[tim cubbedge]

Missile Works is having sale through end of day December 2. Jim makes great products & excellent customer service.

 

[Wallace]

If cost is an issue go Eggtimer. If not, go with whatever stikes your fancy. Kate is super cool..In the end, they almost always do the same/similar enough to not notice the difference.

 

[g.pitts]

John-follow Jim's (above) and Tim's advice. They've been doing rocketry since 1812 (rocket's red glare...). Seriously though Jim's instructions (pnisher build) are directly applicable. Also Tim, on the Wildman site under "downloads" has excellent generic instructions. Finally, if you are putting your gps transmitter near an all thread rod, the closeness to such a conductor (steel) will diminish your transmitter range. I suggest, if you do this, get a titanium all thread (doesn't conduct electricity well). They are about 16 bucks from Amazon. I have ground tested it in a "glueless" nosecone bay in a Drago 4XL that contains a gps receiver and 2 meter transmitter. Preliminary testing demonstrates no harm from the titanium all thread in the nose cone.

Fred, L2
ICBM,
Camden, S.C.
KG4YGP

I am in a similar situation as the OP (haven’t yet bought my kit though), and was thinking of using aluminum as it is non-ferrous (same rationale as using Titanium).

Any concerns with the strength of aluminum threaded rod in this application?

 

[FMarvinS]

In my humble opinion, your concerns are warranted. Aluminum is a good electrical conductor, thus its use would both absorb and reflect transmitter propagation. Also, obviously, aluminum is not as strong as steel and it might provide less structural support.

Fred

 

[Tobor]

I know there is a huge aversion to using Nylon threaded rod but, for my UWM L3 I plan on using exactly that. (4x) 3/8" All Thread for the lower AV-Bay to be precise. Of course I will have to prove viability with a few documented tests.

 

[Wallace]

I suspect you'd be fine as long as you're going with 3/8". Just do some testing first, like say a 10lb weight dropped a few feet. And please post results so we all don't need to repeat same?

 

[Tobor]

I suspect you'd be fine as long as you're going with 3/8". Just do some testing first, like say a 10lb weight dropped a few feet. And please post results so we all don't need to repeat same?

Yeppers, that is the plan.

 

[Wallace]

Aye. Good thinking mate..

 

[Ez2cDave]

I suspect you'd be fine as long as you're going with 3/8". Just do some testing first, like say a 10lb weight dropped a few feet. And please post results so we all don't need to repeat same?

Video of the tests would be nice.

Dave F.

 

[cerving]

I am in a similar situation as the OP (haven’t yet bought my kit though), and was thinking of using aluminum as it is non-ferrous (same rationale as using Titanium).

Any concerns with the strength of aluminum threaded rod in this application?

Any metal will have some RF blocking effect, it doesn't have to be ferrous. Lower density and lower conductivity makes Ti a "better" choice... if you can afford it, of course. A fat nylon rod may be a good alternative, but don't be surprised if you find that it's stretched a bit when you get it back... nylon has a terrible yield strength compared to metals.

 

[Wallace]

There are fiberglass threaded rods available, but pretty sure they'd be hard to get and not cost effective..

 

[rharshberger]

There are fiberglass threaded rods available, but pretty sure they'd be hard to get and not cost effective..

And they are only a little better than nylon, the threads won't handle much in the way of shear forces, I looked at using them for my L3 project several years ago.

 

[g.pitts]

There are fiberglass threaded rods available, but pretty sure they'd be hard to get and not cost effective..

Interesting idea! McMaster Carr has them (link to an example below). 3/8" appears to be the smallest offering. They aren't inexpensive for sure, but if you really wanted that extra RF "reach"...

https://www.mcmaster.com/91315a031

Another option might be acetal, although it is ~1/4 the shear strength of aluminum...

https://www.mcmaster.com/98873a200

 

[mbeels]

I've threaded fiberglass rod (48" driveway markers, $1 each) before with a die. I think that the strength is greatly reduced though, because the die cuts the lengthwise fiberglass threads which carry the load. (My use wasn't for rockets)

 

[mbeels]

I'll add that I used JB weld to epoxy a 5/16" clevis onto the threaded driveway marker, and the result seemed to be quite strong.

 

[Tobor]

Okay I forgot to report on the UWM threaded NC tip. So, here I go better late then never...

 

[dhbarr]

Any metal will have some RF blocking effect, it doesn't have to be ferrous. Lower density and lower conductivity makes Ti a "better" choice... if you can afford it, of course. A fat nylon rod may be a good alternative, but don't be surprised if you find that it's stretched a bit when you get it back... nylon has a terrible yield strength compared to metals.

Titanium bike spokes are relatively inexpensive.

 

[Wallace]

Okay I forgot to report on the UWM threaded NC tip. So, here I go better late then never...
View attachment 400153

I like seeing that it has a shoulder, alot of 'em don't. Dimensions, weights?

 

[Tobor]

I like seeing that it has a shoulder, alot of 'em don't. Dimensions, weights?

Nope sorry. I didn't think to spec out the pieces. If I remember to do it when I get home, I'll correct that.

 

[Wallace]

Just out of curiosity, why are Ya'll threading driveway markers? Mine simply push into the ground or screw to a post?

 

[Wallace]

And, never having done it so I cannot speak with any authority...Seems like a non-good idea to cut threads in a fiber-anything type rod..

 

[cbrarick]

why not take your gps system out of the ebay?

I have a 2.6 inch loc coupler with a bulkhead on it. It slides into some 2.6 loc body tube with a bulkhead on it. This bulkhead has a eyebolt with a kevlar 600 pound line on it I can quick link to a ebay. The body tube and coupler slide together to form a enclosure for it - and I wrap my gps in bubble wrap so it doesn't bounce around. Done and done, and you can go back to using strong all-thread...

 

[mbeels]

Just out of curiosity, why are Ya'll threading driveway markers? Mine simply push into the ground or screw to a post?

It was for a purpose completely unrelated to rocketry and driveways, I just mentioned it because threaded fiberglass came up. It was actually a support for a mobile amateur radio antenna, so could not be conductive. The 5/16 clevis was attached to something with 1/4" galvanized nuts and bolts. It came out plenty strong for what I needed, but I'd be hesitant to use threaded fiberglass in rocketry because of the shock loading.

 

[Wallace]

Got it. Thanks for the pic. Seems they truly are worth a thousand words. Did you consider gluing it? Or did it require adjustabilty?

 

[mbeels]

Did you consider gluing it? Or did it require adjustabilty?

I did JB weld it in place, once I had the clevis in the right position. That mechanically and chemically holds it in place, it was plenty solid for the support I needed at the time. Getting 48" long fiberglass for $1 is pretty cheap compared just about all the alternatives.

 

[richP]

You could always just attach it to the shockcord with a printed sled from Additive Aerospace. Although I would always choose to put it into the nosecone using a removable bulkhead.

 

[bibbster]

why not take your gps system out of the ebay?

I have a 2.6 inch loc coupler with a bulkhead on it. It slides into some 2.6 loc body tube with a bulkhead on it. This bulkhead has a eyebolt with a kevlar 600 pound line on it I can quick link to a ebay. The body tube and coupler slide together to form a enclosure for it - and I wrap my gps in bubble wrap so it doesn't bounce around. Done and done, and you can go back to using strong all-thread...

Would you mind posting pics of this setup?

 

[cbrarick]

here it is. It doesn't need a vent because it just has my gps. Therefore it's pretty impervious to ejection charges. My BRB is in the bubble wrap. The rivets hold everything together until I decide to take it apart (there's 2)

 

[bibbster]

Simple and effective! Thanks for the pics, that clears things up for me.