Two-stage HPR design build

sodmeister said:

Hey Bret ,that`s what I`m talking about......PARTS ,PARTS and more PARTS......

Now it gets interesting.


Paul T

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Here ya go, some more parts put together. The booster (although it's just a dry fit) and the view of the booster business end:

Started on the sustainer today. I tried a new technique (new to me anyway) to cut the fin slots. I used a Dremel Multimax tool. I marked the slots, then taped around them with painter's tape. Then I clamped a piece of anlge steel along the edge of the slot to be cut. I used the steel to guide the Multimax blade. Turned out to be a very a very accurate and straight cutting method...

SteelyEyed said:

Started on the sustainer today. I tried a new technique (new to me anyway) to cut the fin slots. I used a Dremel Multimax tool. I marked the slots, then taped around them with painter's tape. Then I clamped a piece of anlge steel along the edge of the slot to be cut. I used the steel to guide the Multimax blade. Turned out to be a very a very accurate and straight cutting method...

Click to expand...

Hey Bret ,good idea ,and I plan on using the alum. angle as a straight edge ,but not with that particular tool.

I`m in the proccess of cutting some short 1/4" wide x 1 1/2" long slots in BlueTube aft section of a project.Normally I use a sled and carbide spiral bit in my router table ,but since these are short slots,I was going to cut them freehand with my Dremel rotary tool.

Have you ever done this with that little "circular saw" blade and arbour attachment or just the heavy abrasive cutting wheel ?

Thanks

Paul T

sodmeister said:

Hey Bret ,good idea ,and I plan on using the alum. angle as a straight edge ,but not with that particular tool.

I`m in the proccess of cutting some short 1/4" wide x 1 1/2" long slots in BlueTube aft section of a project.Normally I use a sled and carbide spiral bit in my router table ,but since these are short slots,I was going to cut them freehand with my Dremel rotary tool.

Have you ever done this with that little "circular saw" blade and arbour attachment or just the heavy abrasive cutting wheel ?

Thanks

Paul T

Click to expand...

Paul,
For all my previous projects that used Bluetube, I've cut the fin slots by hand with a Dremel tool and abrasive cutting wheel. I tried the little saw blade, but for me the cutting wheel worked best.

Cheers,
Bret

Thanks Bret ,I`m off to THE home depot in the next hour.

You`re not talking about this one are you ?

Thanks

Paul T

sodmeister said:

Thanks Bret ,I`m off to THE home depot in the next hour.

You`re not talking about this one are you ?

Thanks

Paul T

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Haven't tried that one. But my experience with other saw blades is that they make it difficult to adjust your cut line when cutting by hand. Whereas, the abrasive wheel allows easier "corrections" to a cut.

Thanks Bret ,appreciate the info.

I still see I`m out of abrasive blades ,so off shopping I go

Cheers

Paul t

Here's the completed aft airframe tube for the sustainer with fin slots cut and rail lug holes drilled...

Awesome work as usual Bret!

Okay, here's what I'm thinking about how the stages will be coupled. Three 1/4" rods that will slide into receiver "sleeves" passing through the aft centering rings of the sustainer. Pics below show what I'm talking about...

Note: There will also be another smaller diameter tube through which the ingniter wires will run from the av-bay.

One other thought, that I think would be cool... I can add a small segment of 3" body tube and a nose cone onto the booster and fly it in a stand alone single deploy configuration.

That`s also a good idea.I find this rendition looks very much like an artillery round or upscale .50 cal. round.

Both are good !!

In fact ,I`d like to do a .50 cal. round as a rocket ,painted brass & copper.I may have finally found a use for that LOC 4-3" transition :confused2:

Paul T

sodmeister said:

I find this rendition looks very much like an artillery round or upscale .50 cal. round.

Both are good !!

Click to expand...

Yeah, that thought crossed my mind when I first saw it too.

Got a couple more "small" things done today, 1) installed the aft PML rail lug on the booster (which will be removed for painting), and 2) fabricated the two rail lug mounts for the sustainer (I cannot install them yet until I figure out the order in which I will install the MMT and centering rings in the sustainer)...

Taking a couple of a detours on the project this week. I decided to figure out how to build a jig to bevel the fins on the booster. Did some googling a couple days ago, found some info that looked useful, and built a jig tonight. We will see how well that works tomorrow...

Also, I've decided to build another copy of the sustainer. I'm going to build the Bluetube version that I've already started with a 54mm MMT and build it as a single stage bird. I've been looking for an excuse to build a rocket using GLR's Magna-Frame tubes, so I ordered some 3" Magna-Frame to give it a try on this project. I'm going to build another upper stage (sustainer) out of Magna-Frame (and build that one with a 38mm MMT to accomodate the staging configuration). So I'm waiting on the GLR order to be delivered before I can continue on the sustainer...

Bret ,

I`m glad you are getting the Magna Frame ,as i`ve wondered how it is to work with and it`s pros & cons ,although it seems to be similar to BlueTube in a way.I look forward to your opinions on the product ,been looking to buy some to experiment with.

Have you ever used Dyna -Wind ?

May I ask you how on earth you made that boat tail , I can`t seem to figure that one out ,but I like it .......well actually I like boat tails on rockets period !

What kind of transition are you using there ,if I may ask.

Sorry for all the questions ,just a little curious and in need of learning new techniques !

Cheerio

Paul T

OBTW- I used the cut off wheel you suggested ,and it worked out very well ,nice and clean and quick......thanks !!

SteelyEyed said:

Got a couple more "small" things done today, 1) installed the aft PML rail lug on the booster (which will be removed for painting), and 2) fabricated the two rail lug mounts for the sustainer (I cannot install them yet until I figure out the order in which I will install the MMT and centering rings in the sustainer)...

Click to expand...

Sweet rocket!

I was using PML rail lugs on my first two builds. I found that they bound on the launch rails that Aeropac uses - with enough friction that the rocket may not have gotten off the pad and if it did, with questionable stability. I'm not sure if the rail lugs are out of spec or the rails themselves are. Fortunately I was able to borrow a couple of rail buttons. What I'll probably do is mill the slots in the lugs out a bit to give them more clearance.

degreaser said:

Sweet rocket!

I was using PML rail lugs on my first two builds. I found that they bound on the launch rails that Aeropac uses - with enough friction that the rocket may not have gotten off the pad and if it did, with questionable stability. I'm not sure if the rail lugs are out of spec or the rails themselves are. Fortunately I was able to borrow a couple of rail buttons. What I'll probably do is mill the slots in the lugs out a bit to give them more clearance.

Click to expand...

I've used them all. I have previously used GLR Acme aluminum rail lugs, but at least one of the clubs I fly with does not allow metal rail guides. I use std. buttons on most of my builds. For air-to-air missle designs I like the PML rail lug because it looks more like a lifting lug on a real weapon system. I used PML lugs on my L3 build, as well as several other rockets. Have never had an issue with them. It's important that you do not get paint on the surfaces that contact the rail. I always mask those surfaces with tape when I paint.

Bret

Last night I finished building a jig to use with my disk sander for fin beveling. I tried it out today. Works great, and will be a useful tool for years to come. Don't know if this is of interest to anyone else, but it would have been helpful to me prior to building one myself, so I'm posting a few pics of the jig below. It is built with a 10-degree angle on the front face. The notch in the base allows me to angle the front face away from the front of the disc sander to make room for my fingers as I feed the fin through. The base plate has 1/4-20 thread wood inserts, the front face slides on the base and has slots and 1/4-20 thumb screws that allow it to be adjusted and locked into place to accomodate different fin thicknesses. Pics should be self-explanatory...

And here's the end result. Nicely beveled leading and trailing edges on the booster fins (they are made from 3/16 birch plywood). The two-inner trailing edges do not lend themselves to beveling using the jig technique. I sanded them by hand to smooth/round the aft edges a bit.

Hey Paul, I'm not ignoring your questions. I'm on my phone. I will get back to you when I'm on my computer...

Fly straight,
Bret

sodmeister said:

Have you ever used Dyna -Wind ?

Click to expand...

I've used the previous generation of Dyna-Wind tubing (before Magna-Frame), it's a very resilient airframe. I'm guessing the new stuff, made with Magna-Frame tubing is awesome. Haven't tried that yet.

sodmeister said:

May I ask you how on earth you made that boat tail , I can`t seem to figure that one out ,but I like it .......well actually I like boat tails on rockets period !

What kind of transition are you using there ,if I may ask?

Click to expand...

Paul, I'm using PML transitions. To make the "boat tail" I cut the two pieces of Bluetube to the desired length. Then I cut the end bulkheads off of both ends of the aft transition (leaving the desired amount of shoulder length). I roughed up the shoulders on the transition and using JB Weld I epoxied the tubes on each end of the transition. After the JB Weld cured, I used the same technique previously described above to cut the fin slots (simultaneously cutting through the Bluetube and the transition). Another pic shown below. Hope that explanation is sufficient.

Made some progress today. Got the fin can assembled (MMT epoxied into boat tail sub-assembly, fin can tube coupler and zipperless baffle bulkhead plate epoxied in place). The pics below show the first of six booster section fins being epoxied in (the vertical one, the other two fins in the pic are still just dry fit and serve to align the fin alignment guide with the slots).

Note: that rather than having the booster parachute come out the front of the booster airframe, I have this configured for the ejection charge to blow the fin can/MMT out of the aft end of the booster airframe, that's because I want to make sure that the forward transition (which couples the two stages together) is held firmly in place. This will become more clear when I get to the stage coupler assembly...

Steely,
Your recent history with new designs suggests that after you build a "little one" to practice on, you follow it up with an upscale. I want to see a 10" booster with a 7.5" sustainer with 98mm MMTs. N to M or N to N staging would be cool. What do you think?

Z

BTW, your designs are unbelievably cool. Could you please get GLR or Binder to kit this thing?

Thanks for the info Bret ,makes sense !

Cheers


Paul t

RocketSurgeon said:

Steely,
Your recent history with new designs suggests that after you build a "little one" to practice on, you follow it up with an upscale. I want to see a 10" booster with a 7.5" sustainer with 98mm MMTs. N to M or N to N staging would be cool. What do you think?

Z

BTW, your designs are unbelievably cool. Could you please get GLR or Binder to kit this thing?

Click to expand...

RS,
Don't you know I've already done those scaling calculations... that bird in two stage configuration would be over 16 feet tall. I'm guessing it would weigh in well over 120 lbs dry. It would be cool, but I'm not going to get ahead of myself. I need to make this one work as planned before I start thinking about a jumbo version. Hey, I appreciate the compliment too. Actually I think it would be kind of cool if someone marketed a pair of kits that could be purchased and flown separately and then combined into a two-stage bird. It would be expensive. Don't know if there is a market for it...

Cheers,
Bret

SteelyEyed said:

RS,
Don't you know I've already done those scaling calculations... that bird in two stage configuration would be over 16 feet tall. I'm guessing it would weigh in well over 120 lbs dry. It would be cool, but I'm not going to get ahead of myself. I need to make this one work as planned before I start thinking about a jumbo version. Hey, I appreciate the compliment too. Actually I think it would be kind of cool if someone marketed a pair of kits that could be purchased and flown separately and then combined into a two-stage bird. It would be expensive. Don't know if there is a market for it...

Cheers,
Bret

Click to expand...

Buy 2 rockets, and make ONE!!!! (I think its better the other way around)

In between over eating and watching football today, I've been working on the shear pin plate locations for the booster fin can. Using a sanding drum on a Dremel tool I sanded out three shallow spots (equally spaced at 120 degrees apart around the booster coupler tube) in which brass shim stock will be epoxied in place. Note: back sides of shear plates roughed up so the epoxy can "get a bite." After completing this step I will drill the shear pin holes through the forward airframe tube and shim plates. Pics below show some examples...

I just bought the FeatherWeight Raven Black Saturday deal. So, that settles it, the sustainer will be flying with the Raven and the MissileWorks WRC+ in the av-bay. Earlier today I ordered an Adept22 alt for the booster. I plan on placing the Adept in the forward transition of the booster...