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

[chadrog]

Looks awesome Layne, Do you have a flight date set?

 

[Pem Tech]

Looks awesome Layne, Do you have a flight date set?

Nothing set in stone at this time, but Troy has been trying to get me to come to AirFest.

 

[troj]

Nothing set in stone at this time, but Troy has been trying to get me to come to AirFest.

Call me Troy again, and I'm gonna steal your Ballz.

-Kevin

 

[rocketgeek101]

Call me Troy again, and I'm gonna steal your Ballz.

-Kevin

:lol::lol::lol::lol::lol::lol::lol::lol::lol:

 

[chadrog]

Call me Troy again, and I'm gonna steal your Ballz.

-Kevin

Hope someone has a camera handy when that goes down.

 

[Pem Tech]

Call me Troy again, and I'm gonna steal your Ballz.

-Kevin

Ooppssie...
Troj...
IT was a innocent typo.
Yeah, yeah, sure.

Touch my Ballz there will be a fight!
Or you could just buy me drinks first.

 

[Pem Tech]

Okay, we are in the final stretch. This build thread will be completed by August 31, even if it hair-lips everyone on bear creek!

 

[Pem Tech]

Okay, forget about the BT-55 cylinder tanks. After getting the rail buttons installed I had to drop the size to BT-50. However, this means I don't have to go through the mess of CA and paper end covers. Over the years I have collected billions of CR cut outs, the little disk removed to make the disk a centering ring. It just happens I had the perfect size, cut from light ply, to fit inside the BT-50 tubing.
:smile:




Here the BT-50 tanks mounted and the reattaching of the rudders. This time moved further forward on the wing and secured with epoxy. Maybe a little FG to make sure they don't even think about coming off.

 

[Pem Tech]

And a question for the experts....
There is 1.25" of motor tube extending from the after of the HMAS Bonestell, is this long enough to mount a Quick-lok Slimline motor retainer?

 

[Sailorbill]

Yes. You only need a little over 0.5" to attach any Slimline retainer.

 

[Pem Tech]

Yes. You only need a little over 0.5" to attach any Slimline retainer.

Thanks!!

 

[Pem Tech]

All righty, the rudders are on, the eyebolt is installed in the NC.
At this point she is ready to fly.
That is without paint or primer....

Pics tomorrow.

 

[Pem Tech]

And here are the final pics of the Official HMAS Bonestell L2 build.
Here is the NC bulkhead and eyebolt secured by 2 largish nails and lots of Urethane glue. Yes, it's ugly but it ain't coming out of there.


Now the issue of grinding the nails flush with the NC surface. AFter the move my drellel is MIA, so I attached the disk cutting head to my drill. That should work, right?
*cough*
The drill could not produce sufficient rpm to even scratch the nail heads. So, today was Lowes Visitation Day! Came home with a 4.5" angle grinder, clamps, brush wheel, more urethane glue, replacement JB Weld and so forth and so on.
Here are the results of the grinding on both the head and pointy ends of the nails. Yes, ugly but merely cosmetic issues.



And finally, nekkid as the day she was born, is the completed 4" upscale HMAS Bonestell!! Final weight, less shock cords, chutes or motor is 128 oz.


During final prep I suffered a panic attack and talked myself into going single deploy, engine eject. However, after a thorazine dart and a calming talk with Kevin I got through that and realized DD is the only real way to go. So the call has gone out for a CTI J380-SS. The flight will be the end of September. Stay tuned.

 

[Pem Tech]

And may the gods help me, I have built again.

On breaks from completing the L2 Bonestell I built this.

Someone, stop me before it is too late!!

 

[Pantherjon]

It is already too late Layne...Expect the van with some very nice people in white lab coats* to come visit you soon!:tongue:


Rocket is looking quite sexy there!:wink:...Can't wait to see the launch report!


*Folks in the white are to check on the well being of a wayward Llama

 

[Pem Tech]

The Wildman Delivery Llama has arrived!!



Hari H. Krishna this thing is big, compared to the motor sizes I am used to.
This is going to be glorious...
The Heavens shall open...
And my Ballz shall fly!
:flyingpig:

 

[troj]

Hari H. Krishna this thing is big, compared to the motor sizes I am used to.
This is going to be glorious...
The Heavens shall open...
And my Ballz shall fly!

Deep, cleansing breaths, Layne.

Step away from the llama, Layne.

No, Layne, step away from the lla....

 

[Pem Tech]

Deep, cleansing breaths, Layne.

Step away from the llama, Layne.

No, Layne, step away from the lla....

My Llama's and I have an "understanding."
:wink:

 

[Pem Tech]

HOLY SMOKES!!!
Fully loaded this thing is heavy! (Compared to what I am used to, so the L3 don't laugh at me.)
13.25 lbs.
Rock sim did a good job on the CG, it said 36" and I got 38" from the nose.
RS margin of stability says 2.71, but I'm thinking it will be less due to the Ballz. Just a hunch.

 

[Pem Tech]

Holy Shaitan with sushi!!!
Been working with ejection charges and shear pins and boy did I get a surprise.

The background...
The main chute is fore of the avbay, and the upper airframe (just BT and NC) weighs three pounds. So I am concerned that at apogee when the drogue deploys the shock will allow the fore airframe to pull away from the avbay deploying the main chute near apogee. Thus the sheer pins. Still experimenting with the toothpick idea and it seemed two would be sufficient until I did a drop test from three feet. Just the nose weight sheared them right off. So I went with four, the drop test showed there was some separation but the coupler held tight. Today I tested the four pins with 2 grams of FFFFg powder.
Boy was I surprised.
BOOM!
[video]https://pembertontechnologies.com/images/SUNP0003a.AVI[/video]

WHile I didn't measure the distance it looks like the upper airframe landed 10 paces away.
ANy guesses? Incorrectly weighed charge, the addition of two more pins, leprechauns?



Oye! I have to get this all worked out by Saturday!

 

[chadrog]

I like bundling my shock cords to help dissipate ejection shock, it has worked well for me. I do two wraps of masking tape around the center of as many (3 to 4 wrap) bundles as I can fold into the cord.

 

[Pem Tech]

Hey I like that.

 

[Pem Tech]

And here is the recover harness V1.0.
Statring at the aft airframe, six feet of SC with a loop for the drogue chute with an additional foot or two to the AVbay. From the avbay to the upper airframe 12 feet of SC with a knot at the aft opening of the upper airframe to avoid zippering. Then 25 feet of SC to the main.



Advice is welcome...
I have plenty of SC and will follow sound advice.

 

[Pem Tech]

OK, already found one problem. There needs to be more SC between the aft of the avbay and the aft airframe or the airframe halves will beat each other like like step children on decent.

 

[daveyfire]

Today I tested the four pins with 2 grams of FFFFg powder.
Boy was I surprised.
BOOM!

Did you change your charge packing method between your last test and the current test? Changing the degree of confinement on the black powder (e.g., more wraps of tape, tighter charge packing, different charge container) will definitely change the results. Also, make sure you ground test with everything in its close-to-final recovery configuration; blowing the nose off is much different when the charge also has to shift the chute/wadding/cord/protector, too.

Good luck with the flight!

 

[rocketgeek101]

Nice looking rocket. Good luck with the flight!!

 

[Pantherjon]

<snip>or the airframe halves will beat each other like like step children on decent.

Not necessarily..At apogee most likely the 2 parts of the rocket will be on the same plane horizontally..Unless you have a really large drogue or a LOT of SC between the drogue and the aft end of your avbay that would allow the forward section to 'fall' and maybe come in contact with the aft section..

I think the most likely scenario with your rocket is that at apogee event, the fin can(since it is pretty draggy) will be slightly above the nose section, if going drogueless(my preferred method BTW)..Having the small drogue close to the aft end of you avbay should keep it above the fin can and out of harms way when the main charge goes off..BTW, I use 'pop rivets' to secure my avbay to the upper tube housing the main(dirt cheap at McMaster-Carr, part # 91020A218)..

 

[Pem Tech]

Call me Troy again, and I'm gonna steal your Ballz.

-Kevin

Hope someone has a camera handy when that goes down.

:lol::lol::lol::lol::lol::lol::lol::lol::lol:

:tongue:

Did you change your charge packing method between your last test and the current test? Changing the degree of confinement on the black powder (e.g., more wraps of tape, tighter charge packing, different charge container) will definitely change the results. Also, make sure you ground test with everything in its close-to-final recovery configuration; blowing the nose off is much different when the charge also has to shift the chute/wadding/cord/protector, too.

Good luck with the flight!

All factors seemed to be the same except the space was empty. I was expecting a much less energetic separation.system

Now that I have the recovery system in it's final state, full runs start this week.

Nice lookining rocket. Good luck with the flight!!

Thank you! I am quite proud of her.

Not necessarily..At apogee most likely the 2 parts of the rocket will be on the same plane horizontally..Unless you have a really large drogue or a LOT of SC between the drogue and the aft end of your avbay that would allow the forward section to 'fall' and maybe come in contact with the aft section..

I think the most likely scenario with your rocket is that at apogee event, the fin can(since it is pretty draggy) will be slightly above the nose section, if going drogueless(my preferred method BTW)..Having the small drogue close to the aft end of you avbay should keep it above the fin can and out of harms way when the main charge goes off..BTW, I use 'pop rivets' to secure my avbay to the upper tube housing the main(dirt cheap at McMaster-Carr, part # 91020A218)..

Is this closer to what you suggested? Moved the 24" PML drogue close to the avbay. Also moved the NC closer to the avbay as well. ANd using chadrog's tape trick should take some of the shock out of both events.
Ordered the 2-56's today for the separation between the upper airframe and the avbay at main chute deploy.

 

[Pantherjon]

View attachment 146053

Is this closer to what you suggested? Moved the 24" PML drogue close to the avbay. Also moved the NC closer to the avbay as well. ANd using chadrog's tape trick should take some of the shock out of both events.
Ordered the 2-56's today for the separation between the upper airframe and the avbay at main chute deploy.

By George, it is indeed!

Maybe I didn't follow along close enough, but, I thought the main was coming out the TOP(or nose cone) end of the upper section and the avbay was attached to the bottom semi permanently..But, this way will work as well!

You getting anxious to fly it? I KNOW I am anxious to see it fly! :wink:

 

[troj]

Something else to consider in your charge reaction is your choice of shear pins -- wooden toothpicks. You're going to find a lot more variety, as grain will make a difference. That's where plastic will be better, as it will be more consistent.

-Kevin