Pem-Tech's Level 2 Build - "Certify With Us" program

[Pem Tech]

Nah,
It'll work fine. Just use microballons or colloidal silica to thicken it up for fillets. Being more fluid allows it more time to soak into the cardboard. If you think the West is runny, try ProLine. That stuff is almost like water.

Adrian

May have to try that....
But I plan on using wood glue for the fillets, if possible.

 

[CarVac]

Nah,
It'll work fine. Just use microballons or colloidal silica to thicken it up for fillets. Being more fluid allows it more time to soak into the cardboard. If you think the West is runny, try ProLine. That stuff is almost like water.

Adrian

I've found that laminating epoxies soak into cardboard less than Aeropoxy ES6209, which has an extremely high affinity for wood and paper.

 

[Pem Tech]

https://giantleaprocketry.com/products/components_composites.aspx

For 25 dollars you can get a pint kit of Aeropoxy Structural Adhesive (ES6209), which is a 1:1 mix, doesn't run much, spreads thin, and soaks into wood and paper with zeal, strengthening the bond. It is not carcinogenic and doesn't smell bad. Since you probably won't do any fiberglass layups, this is really what you want.

If you control how much you use (it doesn't take much at all), a pint will last years. And you'll probably be more inclined to use it than the laminating epoxy you have. If you get used to it, you might just start using it instead of wood glue for anything which doesn't require initial tack.

Hmmmmmmmm....
Very interesting.....
No gloves?
No odor?

 

[CarVac]

Hmmmmmmmm....
Very interesting.....
No gloves?
No odor?

The no-gloves deal is only because I am able to use it without ever dripping.

Thanks to its unusual viscosity properties, I can glob up about a centimeter diameter sphere of the epoxy and keep it perched on the end of a normal-sized popsicle stick by rotating it around, so I don't really need gloves.

Another trick I used when making Disappearing Act: I used the same plastic mixing cup six times in a row: I left the popsicle stick in the leftover epoxy, then just peeled the stick with attached epoxy out of the cup once it was hardened, and used the cup again.

Perhaps I should get someone to take a video of me using it...

 

[jd2cylman]

I've found that laminating epoxies soak into cardboard less than Aeropoxy ES6209, which has an extremely high affinity for wood and paper.

I'll defer to you on this. I've only used West and ProLine.

Adrian

 

[Pem Tech]

And the altimeter on the sled inserted into the Avbay.


Seems like a lot of extra room in there...

Advice?
Suggestions?
Criticisms?

 

[troj]

Titebond II is plenty strong for this project, Layne.

Your West Systems epoxy will work, as well -- this isn't a build where maximum structural properties is necessary, so laminating resin is just fine.

-Kevin

 

[CarVac]

Titebond II is plenty strong for this project, Layne.

Your West Systems epoxy will work, as well -- this isn't a build where maximum structural properties is necessary, so laminating resin is just fine.

-Kevin

I was not referring to strength, but handling properties, for which ES6209 is the king in my own opinion. Remember, Layne's original issue was that the West was running everywhere, and the wood glue was seizing up too quickly. That would have been the perfect situation for ES6209.

Also, I want to dispel the unfortunately generalized notion that a) epoxy smells nasty and b) is hard to work with and c) is heavy because you have to make giant fillets with it. I used to have all of these misconceptions until I found Aeropoxy.

 

[Salvage-1]

And the altimeter on the sled inserted into the Avbay.
View attachment 115431

Seems like a lot of extra room in there...

Advice?
Suggestions?
Criticisms?

Enough room on the back for a timer and another battery.... AIRSTART OUTBOARDS!!!!

nice work, am looking forward to watching the rest of this, so, where is the compartment for the Llama Pilot? or is this one GnomeControlled(c)

 

[Pem Tech]

Enough room on the back for a timer and another battery.... AIRSTART OUTBOARDS!!!!

nice work, am looking forward to watching the rest of this, so, where is the compartment for the Llama Pilot? or is this one GnomeControlled(c)

Ya know, I have been considering a cockpit for a little stuffed Llama....
:grin:

Air starts?
Hadn't considered that,,,,
WHat would I need, a timer? G switch? Enclobunator?

 

[CarVac]

Ya know, I have been considering a cockpit for a little stuffed Llama....
:grin:

Air starts?
Hadn't considered that,,,,
WHat would I need, a timer? G switch? Enclobunator?

More motor mounts, for one. That might be difficult to fit in 4", with the 54mm central motor.

 

[Pem Tech]

More motor mounts, for one. That might be difficult to fit in 4", with the 54mm central motor.

Yes.......
That is pretty much a given. My question was in reference to electronics.

 

[CarVac]

Yes.......
That is pretty much a given. My question was in reference to electronics.

A Raven is the safest option short a RocketTiltometer.

 

[Pantherjon]

Hey, would anyone know why the top of the hardener can is so stained? Looks like iron oxide but looks more like deposition than corrosion.


Here is the hardener:
View attachment 115393

For comparison here are both the resin and hardener:
View attachment 115394

I wouldn't worry..This is a normal thing for West system hardener to do..Has the liquid inside the can turned a reddish color? Again this is a normal thing for West hardener when it ages...

 

[Pem Tech]

I wouldn't worry..This is a normal thing for West system hardener to do..Has the liquid inside the can turned a reddish color? Again this is a normal thing for West hardener when it ages...

Glad to know that....
West System is expensive!

Now for another noob question. Since the MAWD altimeter will handle both ejection events, what do I do about the delay element?
One would assume you remove the powder charge but what else does one do?

 

[troj]

Now for another noob question. Since the MAWD altimeter will handle both ejection events, what do I do about the delay element?
One would assume you remove the powder charge but what else does one do?

The delay is left, and at its full length. Remove the paper cap holding the charge in, and dump the charge into an appropriate container. Then, stuff dog barf in the well, and cap it with tape.

-Kevin

 

[Pem Tech]

The delay is left, and at its full length. Remove the paper cap holding the charge in, and dump the charge into an appropriate container. Then, stuff dog barf in the well, and cap it with tape.

-Kevin

Excellent! Thanks Troj!
Will still need to stop by the hardware store for sheer pins and rivets.

 

[gdiscenza]

You could also calculate the appropriate delay for your rocket and motor, add 1 second, drill the delay to that number and use motor eject as a backup.

That's what I plan to do.

G. D.

Sent from my iPhone using Forum Runner

 

[Pem Tech]

You could also calculate the appropriate delay for your rocket and motor, add 1 second, drill the delay to that number and use motor eject as a backup.

That's what I plan to do.

G. D.

Sent from my iPhone using Forum Runner

WHich leads to another question, since the time from burn out to main deploy at 700 AGL is WAY past the max 16 second mark, it could be used for the droge but not the main. The question is, what is the preferred positioning of droge and main? I've seen some with the droge aft of the avbay and some with the main aft of the avbay. WHat are the advantages of either?

 

[troj]

WHich leads to another question, since the time from burn out to main deploy at 700 AGL is WAY past the max 16 second mark, it could be used for the droge but not the main. The question is, what is the preferred positioning of droge and main? I've seen some with the droge aft of the avbay and some with the main aft of the avbay. WHat are the advantages of either?

The most common approach is the drogue is close to the motor, and the main is at the nose.

The reason is that if your drogue is at the nose, then the entire weight of the rocket is hanging on the shear pins holding the main in, so it's more likely to give you an early deployment.

-Kevin

 

[Coop]

...also helps with stability margins--placing the heavier main at the fore end can reduce or eliminate the need for nose ballast...


Later!

--Coop

 

[Pem Tech]

The most common approach is the drogue is close to the motor, and the main is at the nose.

The reason is that if your drogue is at the nose, then the entire weight of the rocket is hanging on the shear pins holding the main in, so it's more likely to give you an early deployment.

-Kevin

...also helps with stability margins--placing the heavier main at the fore end can reduce or eliminate the need for nose ballast...


Later!

--Coop

Geez....
NOW you guys tell me that....
:bangpan:
But I think I can switch the chutes with little trouble.

 

[Handeman]

Geez....
NOW you guys tell me that....
:bangpan:
But I think I can switch the chutes with little trouble.

The advantage of having the drogue at the top is that the rocket will line up vertically below the drogue chute and drop much more quickly with a minimum of side drift.

Have you ever seen a DD rocket come down with the fin can leading, tilted at a slight down angle, the fins acting as wings and flying along, pulling the upper section behind it. I've seen 2,000 ft flights move 500 - 600 feet crosswind on the way down to main deploy. The problem is you don't know which way it will go, with, against, or cross wind. Of course this is usually only a problem on DD flights that split in the middle and are drogue-less. You can negate this effect with a drogue that keeps the fin can vertical, but with a split in the middle, it usually takes a larger drogue and slower drop speed to get the same vertical drop profile of a top section deployed drogue. Of course the slower drop speed means a further walk.

 

[Pantherjon]

I see both your questions have been answered, Layne..Just a couple of tidbits..The delay is left whole-after dumping out the black powder- as it makes a most excellent tracking smoke trail..Also about the parachute placement, I go drogueless..But, when the apogee charge fires and separates the rocket, "ideally" you want both sections to be near the same mass so that as the rocket descends it is in a line horizontally. Since you are using a drogue chute I would place it right at the eyebolt on the aft end of the avbay/coupler.This will make sure the upper section is above the fin can so when the main comes out there is not a chance for the chute getting fouled-seen it happen and it weren't pretty...

 

[Pem Tech]

OK, now that the norovirus has passed (bad pun) I had a chance to put the shock cord mount on the fore CR. This is something I have never done before, usually tying the shock cord to the MM and slipping it under the fore ring. But having read a recent thread about replacing shock cords on HPR rockets I thought this would be a wise edition.
And here it is, slightly flavored with urethane glue...


Look deeply into my eyelets.....

 

[Pem Tech]

O.K., now I remember why I bought the West System epoxy...
While poking through the "Why do you Be Fiberglassing Evarthang" thread it struck me that when first returning to rocketry there were so many fiberglassing threads I was under the impression that all of MPR/HPR builds needed fiberglass. So, seeing West Systems recommended so highly for FG that was what I got.Then I talked to a nice young man at a launch years ago, he was flying a 7" rocket that wasn't FG'd. He told me wondrous tales of cardboard rockets flying on J motors or larger. I've been a cardboard fan since....

 

[troj]

O.K., now I remember why I bought the West System epoxy...
While poking through the "Why do you Be Fiberglassing Evarthang" thread it struck me that when first returning to rocketry there were so many fiberglassing threads I was under the impression that all of MPR/HPR builds needed fiberglass. So, seeing West Systems recommended so highly for FG that was what I got.Then I talked to a nice young man at a launch years ago, he was flying a 7" rocket that wasn't FG'd. He told me wondrous tales of cardboard rockets flying on J motors or larger. I've been a cardboard fan since....

West Systems will work just fine for the build you're doing, Layne.

And I build a lot of wood/cardboard rockets with Titebond II. We flew a Q motor where the entire structure was made with Titebond II....

-Kevin

 

[ClayD]

West Systems will work just fine for the build you're doing, Layne.

And I build a lot of wood/cardboard rockets with Titebond II. We flew a Q motor where the entire structure was made with Titebond II....

-Kevin

that largely held together on inpact too boot....

 

[ClayD]

O.K., now I remember why I bought the West System epoxy...
While poking through the "Why do you Be Fiberglassing Evarthang" thread it struck me that when first returning to rocketry there were so many fiberglassing threads I was under the impression that all of MPR/HPR builds needed fiberglass. So, seeing West Systems recommended so highly for FG that was what I got.Then I talked to a nice young man at a launch years ago, he was flying a 7" rocket that wasn't FG'd. He told me wondrous tales of cardboard rockets flying on J motors or larger. I've been a cardboard fan since....

west; like proline, was recomended to me early on solely for its "cleanliness" Pump dispensing self.... I know there are others that are volumetricly dispensed, but, this seems widely available due to the boat world. (if it floats it can fly.???)

a trick i have found with west, is to put a thin layer on before you fiberglass it. I like to try to fill my weave from the bottom up... i get better fiber epoxy ratio that way.(i picked that up in thier tutorial videos, and thier customer service people are good.)

 

[jd2cylman]

that largely held together on inpact too boot....

WoW!!!

op:

Adrian