Anima Mundi

[patelldp]

Very impressive build. Still planning on an N2000W for Red Glare? I hope to see the flight, as well as see this beast up close.

Any work accomplished on the nose cone?

 

[Feckless Counsel]

Dan,

Thanks for your reply and yes the plan is still Red Glare 12. It's going to be close.

The motor I've ordered is Cesaroni N3301. As you predicted I'm now estimating between 165 and 175 pounds pad weight. That motor yields 1100 pounds thrust for 400mS, then 900 pounds thrust for 2 seconds and then slopes out for a total burn time just under 6 seconds. Any comment on thrust to weight ratio here?

Nose cone is sanded and rings are prepared for epoxy. Problem of the week is attachment strength especially where recovery is concerned. Do I rely on epoxy alone? More pin blocks? More structure? But I'm already heavy. Hmmm!

Feckless Counsel

 

[Feckless Counsel]

TRF,

Test fit booster to middle airframe.

Feckless

 

[dixontj93060]

TRF,

Test fit booster to middle airframe.

Feckless

OH YAH!!!!! THAT'S ONE SWEET BEAST!!! (WISH I COULD SEE IT FLY!!!)

 

[stantonjtroy]

TRF,

Test fit booster to middle airframe.

Feckless

:jaw: DUDE!! I SOOOO can't wait for RG.

 

[SMR]

TRF,

Test fit booster to middle airframe.

Feckless

Wow, the photo really puts the size in perspective. Great looking rocket.

 

[daveyfire]

That motor yields 1100 pounds thrust for 400mS, then 900 pounds thrust for 2 seconds and then slopes out for a total burn time just under 6 seconds. Any comment on thrust to weight ratio here?

When I was flying with GBR back at LDRS 21, we accidentally picked up a fully-loaded (220 lb) Porthos on a single N2000 -- not by choice, the center motor had alclo in the head end and the K1050s had just a single unfolded dipped davey. It was slow, but it definitely went up. N3301 has another 225 lbs of push beyond the N2000; you should be fine at 175 lbs.

 

[Eat, sleep, and Fly]

WOW!:y: Size matters!!!:grin:

 

[Rocketman248]

How the heck did I miss this thread?!

I got the opportunity to see the nosecone and tubes up close at a winter MDRA launch. Let me tell you guys, those tubes were a work of art! It takes some serious skill and downright determination to hand lay a set of 22" fiberglass tubes.

Can't wait to see this bad boy go up at Red Glare. This is shaping up to be one hell of a launch!

 

[Feckless Counsel]

Rocketman248,

Thanks for your kind words and encouragement. The project, however, is far from the builder’s art. I’ve made a lot of feckless mistakes both in design and construction. The project, lightweight and thin walled, might fail structurally. The recovery system is unconventional and may fail to deploy.

But all that's good stuff for me and for the community. Whatever else it’s going to be a good show. Look forward to meeting you there.

Feckless Counsel

 

[JStitz]

Those tubes need to be naked. they look fine unfinished.
Take it slow...if Red Glare is a pressure date...just extend and take your time with this beast.:wink:

 

[GDJ]

TRF,

Test fit booster to middle airframe.

Feckless

Ho...ly......COW! That's not a model rocket. That's a bloody ICBM.

Wow. She's a beauty!

So how many gallons of LOX/LH2 are you gonna use for this thing?

 

[Feckless Counsel]

TRF,

Two photos for those who are interested:

1. Edge stock glued to the fins. Fit is pretty tight. Will have to sand and fill just a few spots.

2. Dry fit of Nosecone to airframe. Two things should be noted: cone asymmetry and a high spot at the shoulder. The cone is slightly misshaped; one side is more curved and the opposite is more straight. That manifests itself at the shoulder as a slight bump-out. What can I say? It's movie surplus.

If the cone is to affect the rocket's course then I believe it would pull towards the straighter side. If so then I could use that to my advantage given an understanding of the range. Anyone are to comment?

Feckless Counsel

 

[dixontj93060]

Feckless,

No big deal on the nosecone--just position it so it looks good from the front for the "money shots."

-Tim

TRF,

Two photos for those who are interested:

1. Edge stock glued to the fins. Fit is pretty tight. Will have to sand and fill just a few spots.

2. Dry fit of Nosecone to airframe. Two things should be noted: cone asymmetry and a high spot at the shoulder. The cone is slightly misshaped; one side is more curved and the opposite is more straight. That manifests itself at the shoulder as a slight bump-out. What can I say? It's movie surplus.

If the cone is to affect the rocket's course then I believe it would pull towards the straighter side. If so then I could use that to my advantage given an understanding of the range. Anyone are to comment?

Feckless Counsel

 

[Feckless Counsel]

TRF,

Carbon stringers applied to airframe's interior. Those are 1/8 x 3/8 inch pulltruded carbon in epoxy. Weight is 1.3 ounce each. They were applied on the 1/8 inch edge using Devcon 14320 plastic weld.

Feckless Counsel

 

[SMR]

The cone is slightly misshaped; one side is more curved and the opposite is more straight. That manifests itself at the shoulder as a slight bump-out. What can I say? It's movie surplus.

I agree with Tim. The slightly irregular nose cone will not significantly affect your flight profile. Those fins should easily be able to compensate. I have a couple of commercial molded fiberglass nose cones with the same feature, and haven't noted any wiggle or arcing from it.

The rocket is looking good. You obviously pay a lot of attention to detail, and have put a lot of thought and effort into the build. Looking forward to the flight.

 

[Feckless Counsel]

TRF,

Below is first pass assembly of the rocket. Unfortunately the nosecone fell when we tried to upright. The darn thing split and cracked in several places.

Oh! I am Feckless.

 

[dixontj93060]

TRF,

Below is first pass assembly of the rocket. Unfortunately the nosecone fell when we tried to upright. The darn thing split and cracked in several places.

Oh! I am Feckless.

OMG! And that is what started the whole project in the first place! What are you going to do?! What is the extent of the cracking?

 

[Feckless Counsel]

Tim,

Fortunately I have a well conceived three part plan:

1. Absorb an excessive quantity of alcohol. Sob in my wife's bosoms. Then lash out on friends and colleagues in a confusing bout of rage.

2. Reconcile myself to the fact that it's all my fault. I pushed too hard too fast because I wanted to see the thing standing. Like Aesop's rooster, pride begets the fall.

3. Fix the nosecone because I must. This project has so far proved anything possible when you lack the common sense.

Feckless Indeed

 

[dixontj93060]

3. Fix the nosecone because I must. This project has so far proved anything possible when you lack the common sense.

Actually could be a blessing in disguise. I have cracked nearly a half dozen fiberglass nosecones. If the cracks are well positioned a decent aluminum mesh mold and an epoxy slurry will result in any shape adjustment necessary to make the nosecone true.

BTW, my official position on this is, "if it can happen in the workshop, it's gonna happen at the launch site"--so really, it was only a matter of time; better to find out now before painting and finishing. This is also why I examine all non-filament wound FG nosecones for thin spots and reinforce with Kevlar and foam as appropriate. So, like I said, really it was inevitable (divine intervention by the rocket gods looking out for you).

 

[Feckless Counsel]

Tim,

I agree. If that thing cracked falling 10 feet onto asphalt then it could have failed at the field. Now I understand the weak spots. I've got a lot of cloth, resin and faring filler. Will make it work.

Feckless

 

[SMR]

Actually could be a blessing in disguise.

Absolutely. I zippered one during an ejection charge test. Fixing the zipper and then reinforcing the interior with fiberglass cloth made it a better, stronger nose cone and I have never had another problem with it on the field.

I do, however, approve of your three part plan.

 

[Feckless Counsel]

TRF,

Onto part three of my recovery plan. Please see pictures of nosecone damage below:

1. Tip split on opposite sides along what appears to be a parting line.

2. Base cracked in two places. I assume those cracks are on either side of an impact point.

3. Load bearing plate pulled out from the nosecone. Note the matt fibers pulled away in layers.

The plate failure worries me most. That was to support the load at recovery. If bonding between layers is incapable of supporting recovery loads then I have a serious problem.

Feckless Counsel

 

[GregGleason]

... The plate failure worries me most. That was to support the load at recovery. If bonding between layers is incapable of supporting recovery loads then I have a serious problem.

Feckless Counsel

Sigh.

That's looks worse than I had imagined. Now I'm wondering if the nose cone is flight worthy and can stand up to the basic aero loading on ascent. If there is a weak spot somewhere that you can't see, then the cone may collapse, and ...

I know that's not what you want to hear, but it may be time to consider making your own nose cone, so you can control how it is made.

Or you can do a lot of 12 oz matte layup on the inside. It could wind up being really heavy, but at least you might increase the confidence level.

I would hate to see that the inspiration for the project, wind up as the "Achilles Heel" of the project.

Greg

 

[Feckless Counsel]

Greg,

I scrubbed an interior test location until the nosecone material appeared solid and homogeneous. Then I applied a test block using Devcon 14320. That is a methyl methacrylate adhesive in a carbon tetrachloride carrier. If that can't achieve a satisfactory interior bond then I agree it's time to start fresh.

Feckless Counsel

 

[stantonjtroy]

With reguard to your plate bonding problem, an Idea for consideration. The weak link appears to be the bond to the Matt; Specifically to the realatively small bonding area. My thought was to first bond a ring to the inside base of the cone, comperable to a centering ring in form, recessed in from the lower edge the thiscness of your plate. Make the center opening diameter roughly 4" or so less than the outer diameter. From here you can reach in and run glass cloth from the upper face of the ring onto the inner sides, X" up the inside of the cone. "X" being whatever distance you feel will provide you with enough bonding area into the cone to provide the strength you need, Kind of like a long glass cloth fillett. Then you can bond, or bolt, the plate to this ring. Bolting could give you access to the interior of the cone should you have future need. I did this on my Upscale Red Max and it proved sucessful and usefull.
Additionally, if the weight penalty wouldn't be too high you could take about 6 to 8 strips of carbonfiber biweave cut 3"-4" wide, 45deg on bias and bond them to the interior surface, base to tip, equadistant around the circumference to act as laminate stringers. It would increase the overall strength of the NC without the need for a total rebuild. Food for thought.

 

[JStitz]

I have never built any thing this big and am new to G-10 and G-12 airframes, but have been mulling this over in the old brain and wondering if anyone is bolting across the tubing just in front of a bulkplate. I guess it would be twin aluminum all-thread on either side of the motor tube ...or in the nosecone case for Feckless it could be 3 or 4 in a pattern.
Of course if your fears of how the prop guy built the cone this could just rip off the lower part of the cone.

This all started me wondering if Epoxy rivets are used by anyone that has been currently building Fiberglass airframes..I was wondering if people are just gluing these up like its cardboard. These are solid fiberglass airframes and I can't imagine how anyone would just epoxy these bulkheads and say a prayer. (yea..this means you)
There will always be the guy who says."Worked fine for me!"...yea..but for how long.
Even Fusor and these space age glues have a limit...and solid fiberglass airframes allow NO resin absorbing.

 

[Feckless Counsel]

JStitz,

Thank you for your kind words.

I agree. The adhesion problem is both difficult and safety critical. May I refer you to post #115 and to post #122 within this thread? I look forward to your comments.

Feckless

 

[JStitz]

Feckless, I have used 6-32 screws into my 1/2" or double 1/2" sandwich wooden bulkheads with positive recoveries so far (fingers crossed) but I honestly don't know how to do this with solid fiberglass bulk plates.

You are delving into Jumbo Territory that most of the forum hasn't gotten into..YET.
I don't think epoxy rivets can be of help here.
I also know you are dealing with a "Fat Cow" that is only getting fatter as you add to the strength of this bird..aluminum hardware will help on weight but I'm not sure how you can build these bulk heads stronger. Fiberglass ring sandwich with a wood bulkhead as the meat?

I appreciate your interest in the normal rocket guys comments,I never launched anything more than a Kosdon L-1860 and I am riveted to your build thread!:eyepop:

 

[Feckless Counsel]

Troy,

Thanks for your comments and great to hear from you. I remember we conceived this project at the APL picnic. I clung to your advice. You thought I was feckless. I ate 30 hot dogs. You drank 30 beers. Was a gilded time for brothers and fellows!

Feckless