Double Configuration 3" Build

[Handeman]

It's been a while since I posted anything. Lots of progress, but nothing to write home about.

Got the aft CR in place so the fin can is together.

I use a 50/50 mix of Titebond II and water to soak some tissue paper and fill in some of the holes in the fin can. The slots were square and the fins were tapered.

Used some US Composites 60 minute laminating epoxy to harden the BT end. I put a thin layer the inch or two inside the tubes and on the ends. I like the 60 min epoxy over CA because it soaks in much further and makes then ends like phenolic.

Here are two pics of the rocket in its two different configurations. The long one with the av-bay should come out about 4 lbs. The shorter configuration, about 2.5 lbs. I have a 3" nose cone with 4 oz of shot in the tip. I may have to use that on the short configuration to keep it stable.

 

[Handeman]

Made a little more progress lately.

I decided to thicken and shape the fins. For that, I make two patterns, cut out a dozen pieces of 0.250" thick balsa and glued that to the outside of the fins.

The first pic is the patterns I cut from the cardboard on the back of a pad of paper.

The second pic is the balsa pieces.

The third is the first fin getting the balsa glued on. I'm using Titebond II and leaving them clamped up a least 6 hours.

 

[cwbullet]

I like the double fin design. They seem to always fly nice with a great sound report.

 

[Handeman]

I like the double fin design. They seem to always fly nice with a great sound report.

That's what I'm hoping. I hope I don't mess up the whistle with the tapered fins.

 

[Handeman]

Ok, I'm looking for a name for this rocket. It got two configurations, the 34" booster with nose cone, and 34" booster with 24" payload and nose cone.

I'm looking for something I can put across the two parts, like "Bumble" on the payload and "Bee" on the booster so I can have a name on the rocket that makes sense in both configurations.

A few lame ones I came up with are:
Black Hole Shot
Sky Blue Flyer

Any suggestions are welcome, you guys have to be able to do better then me!

 

[qquake2k]

Hmmm...

"Split Infinity"

"Six Degrees Of Separation"

 

[Handeman]

I think I said at the start of this build, it was going to be a slow one. I'm sure ya all figured that out by now.

Anyway, I finally got around to shaping the fins.

First I taped the fin, marking the line I wanted to sand to. Once the sander started taking some of the tape, I would know I had sanded far enough.

I use my 1/4 sheet finish sander.

These three pics show the taped fins and the initial sanding. It was sanded to taper back from the fin tip to the BT.

 

[Handeman]

Once the first angle was done, I taped the fins for the sanding the second angle. This was parallel to the leading and trailing edges of the fins.

The first pic shows the tape applied. I taped about 3/16" on the leading and trailing edges of the fins, just to protect them from the sander.

The next two pics show the final sanding done. You can see how the tape on the leading and trailing edges was hit be the sander, but the edges were fine.

 

[Handeman]

The next step was to remove the tape and clean up the rough sanding with the hande dremel tool using the 1/2" sanding drum.

Here's two pics that show the final shape. The dremel did a good job of cleaning up the rough shape the sander did. The final step was a sanding block and 150 grit sand paper.

 

[T-Rex]

Wow, that is amazing craftsmanship!

I'm a pro scrap and sawdust maker myself. Seriously by the time I give up all that is usually left is scrap and sawdust.

My rockets (dog houses, chicken coops, etc) aren't pretty, but they usually work, sorta, for a while.

 

[Handeman]

Since the balsa on the fins is just for shaping the airfoils, not strength I'm debating about how or if I should harden them.

The first option is to coat them with 3 oz glass. The problem I have with this, beside the excess weight, is the leading and trailing edges. My experience with sharp edges is that the glass cloth doesn't wrap around and stay flat. I would expect vacuum bagging can correct that, but I don't see that happening at this point.

The second option is to use the US Composites 60 min laminating epoxy to coat the fins. Since this is a 60 min epoxy, it should soak into the balsa quite well and harden the surface. This is what I've used on foam nose cones and it's held up quite well. This should add less weight then using the cloth and still provide a pretty durable finish.

The third option is to just put primer over it. That will also soak in and harden the surface. This works well for LPR balsa fins and since this balsa is just shaping the fin and not part of the edges, this might work just as well. It will need some Elmer's Wood Filler in a few places after the first coat of primer has soaked in, but that would probably be the case no matter which method I choose.

Right now I'm leaning toward option 2, but I'm open to suggestions. What method do you think would work best? or do you have a different method that would work better?

I'm all ears!

 

[Handeman]

Five days and no opinions. That's strange for this group, unless no one is bothering to follow this. That's OK too.

Anyway, I decided to coat the fins/balsa with a laminating epoxy. I mixed up 40cc of US Composites 3:1 60 minute epoxy and coated the fins/balsa. I used a foam brush and by the time I had gone around all the fins, the first coat had soaked in so I put a second coat on everything. This should harden up the surfaces quite nicely.

 

[Handeman]

Made some more progress. Mostly primer and paint with lots of sanding. Boring stuff.

Only have two weeks until the first fall launch at BattlePark

Here's a few pics.

Still in primer. I haven't decided on a colors yet.

The first pic is the lower section. A nose cone and it will fly, or I can add the av-bay and upper payload for dual deployment.

Second and third pics are closeups of the fins. You can see the shape and contour pretty well.

 

[qquake2k]

Made some more progress. Mostly primer and paint with lots of sanding. Boring stuff.

Only have two weeks until the first fall launch at BattlePark

Here's a few pics.

Still in primer. I haven't decided on a colors yet.

The first pic is the lower section. A nose cone and it will fly, or I can add the av-bay and upper payload for dual deployment.

Second and third pics are closeups of the fins. You can see the shape and contour pretty well.

Not boring, it looks good! Those fins should really whistle.

 

[Handeman]

Not boring, it looks good! Those fins should really whistle.

The build may not be boring, but all the sanding sure is

I'm hoping it will whistle really well.

I'm trying to decide if the first flight will be on an I211W in DD config, or an H123W in motor eject config. Of course, I could make the first flight on a J500G If it's going to whistle, that certainly should get the job done.

 

[Handeman]

Got the sanding done, primed, and a white base coat on the rocket. Any suggestions for the paint scheme?

I'll be out at BattlePark this whole weekend. Plan to do my ground testing of the deployment charges on the Friday research day. Not many flights on research days, although there are more now since any Tripoli members can fly commercial motors that day.

It'll probably make its first flight on Saturday.

Here's a few pics.

The first one is both the fin can and upper tube with a nosecone in it.

The next is a shot from the business end. You can see the fin shape pretty well.

The last is a shot of the fins. You can see the profile in the slots of each fin. I'm hoping they whistle on the way up.

 

[Handeman]

This rocket had it's first flight today at BattlePark.

I ground tested the ejection charges first and found that 1 g for drogue and 1.2 g for the main are great plenty.

The rocket was then assembled with my new Statologger altimeter. It was the first flight on the Stratologger too.

It flew on an I211W. It reached 2,754 feet with a maximum speed of 323 mph. I haven't downloaded the flight data yet.

The best part, it Whistled!!!

The next flight might have to be on an I357T with the one second burn time. Get it up to speed fast and be able to really hear the whistle at motor burn out.

 

[MaxQ]

Very Nice clean build....the fin fillets are very well done... appears that the chopped FG did the trick.

What brand paint and primer?

I like whistles...double fins are good for that.
My Binder Raptor always pleases - when the motor shuts down you can hear it whistle to apogee.
Very cool.

 

[Handeman]

Very Nice clean build....the fin fillets are very well done... appears that the chopped FG did the trick.

What brand paint and primer?

I like whistles...double fins are good for that.
My Binder Raptor always pleases - when the motor shuts down you can hear it whistle to apogee.
Very cool.

The primer was Rustoleum Filler Primer and the Paint (white base coat) was the $0.96 Walmart rattle can. They only come that cheap in black and white. The recoat time is within 1 hour or after 1 week. If you can let it sit a week or more, it actually makes a pretty good base coat.

 

[Handeman]

As the title might suggest, the rocket does NOT whistle, at least not audibly.

I've had two flights with the dual deploy configuration.
An I211W that hit 2,754 feet at 232 mph and with an H242T that hit 1,171 and 225 mph.

I also had two flights in the motor deploy configuration. Instead of the av-bay and payload, the nose cone is directly on the fin can. I did use a nose cone that had an extra 5 ounces of weight in the tip.

It was breezy at BattlePark today, 10-15mph. The fist flight was on a F52-5T which got about 300 feet. I could have used a four second delay, but five was OK. The second flight was on a G76-7G which got to about 600 feet. I thought about an H flight, but a Minnie Magg that flew on an H was lost because it drifted too far. I didn't want to duplicate that.

Anyway, this rocket will be a fun flier on anything from Hobbyline 29mm to 38mm J motors depending on conditions and what configuration I want to fly it in. I can see a lot of flights coming up for this one.

 

[geof]

It's been a while since I posted anything. Lots of progress, but nothing to write home about.

Got the aft CR in place so the fin can is together.

I use a 50/50 mix of Titebond II and water to soak some tissue paper and fill in some of the holes in the fin can. The slots were square and the fins were tapered.

Used some US Composites 60 minute laminating epoxy to harden the BT end. I put a thin layer the inch or two inside the tubes and on the ends. I like the 60 min epoxy over CA because it soaks in much further and makes then ends like phenolic.

Here are two pics of the rocket in its two different configurations. The long one with the av-bay should come out about 4 lbs. The shorter configuration, about 2.5 lbs. I have a 3" nose cone with 4 oz of shot in the tip. I may have to use that on the short configuration to keep it stable.

This was an outstanding build! The first part taught me how much better & easier one can do with the right tools, and the entire thread showed incredible craftsmanship. The idea of thickening the fins with extra balsa is new to me, too.

I have a question about the tissue paper step. How do you do it / how does it work? Why not just use wood filler or bondo, which are easier to sand?

Geof

 

[Handeman]

This was an outstanding build! The first part taught me how much better & easier one can do with the right tools, and the entire thread showed incredible craftsmanship. The idea of thickening the fins with extra balsa is new to me, too.

I have a question about the tissue paper step. How do you do it / how does it work? Why not just use wood filler or bondo, which are easier to sand?

Geof

I used the tissue paper because the gaps were quite large. There was a tapered fin coming out of a square ended slot. The tissue paper filled the gaps and there was nothing to run or drip through. I just soaked the tissue paper in wood glue. Just enough to soak the tissue paper. You don't want the glue running all over as you press the paper into the gaps.
The wood filler is much easier to sand and can be used as a final coat over the tissue paper. I don't like bondo, to short of working time and it stinks!

 

[Handeman]

Guess I kind of forgot about this thread.

Dog Whistle as I've been calling it, because I've never heard it whistle, although a few other people have said they did hear it, has made several flight now.

It had one each in the DD long mode and the shorter motor ejection mode the first day out. Both flight went fine.

A later flight in the longer DD mode didn't go very well. It was really an amazing flight because of what did occur.

First I was using ematches from two different batches and both failed. Both read 1-2 ohms before flight, got good beeps on the altimeter and both were open afterward but the pyrogen never burned. These are usually very reliable and to have 2 fail on the same flight, I've never heard of it before.

Second was the fact it didn't lawndart. The flight was over 4,400 feet on a J350 and it fell flat the whole way down. I kept waiting for it to tilt nose down and go ballistic, but it never did.

Third, when I topped the hill on the way to retrieve the rocket, I found out it landed a couple hundred yard into a huge area of standing corn. That wasn't so surprising, what really shocked me was that as I walked through the corn looking for it, I ended up walking right up to it.

Even though nothing seemed to go right, I consider this day a very special day because of all the things that went wrong and still worked out great.


I had been flying the Dog Whistle drogue-less on its DD flight. I have now made a small 12" drogue for it. I found that the way the fin can was flying back and forth on the way down, it was causing small tears in the top of the BT. Not sure I would call them zippers, but it was starting that way. The drogue should stabilize everything and prevent the zipper issue.

 

[qquake2k]

Any flight photos or video?

 

[Handeman]

No unfortunately. Between RSO, LSO, and just all around jawing, I don't fly as much as I would like and usually end up leaving the camera sitting on the seat of the car all day.

 

[Handeman]

Well, I've been calling this rocket Dog Whistle for quite a while now because I just never heard it whistle.

I heard it whistle this weekend!

I launched it in DD configuration on an I285R. The motor burned out about 400ft and I heard it whistle from there to about 1000 ft. It's not as loud as I had hoped, but it was distinct.

Any ideas for a new name?