Finned rockets

[warthog]

Works for me

 

Like I said, it was only something I was curious about since I am just beginning my rocketry as far as fireworking goes and I always seem to have the wrong term for what I and trying to talk about...

[stckmndn]

@VintageRacer any specific info on your tried and true practices would be much appreciated. Was the launch guided or did the little guy take off on it's own. It looks the latter.

 

I am interested in the fin jig dag posted and will go see if I can find it locally tomorrow. Does white glue really hold the fins on?

 

 

 

 

[nater]

i would use wood glue, it holds a little stronger than white glue. for model rockets, i use wood glue or epoxy, then sand the fillet until it is nice and smooth.

[Short5]

A very simple way to make a fin marking guide is to measure the O.D. of the engine, divide by the number of fins you want, then mark a strip of paper on the top and bottom edge with the measurement you came up for the number of fins you want. Wrap the paper strip around the engine and copy the marks off the top and bottom of the strip. You now have a top and bottom mark for the fin.

 

Fins can be placed at an angle or have the leading edge only sanded on one side to impart a little spin on the rocket. Experiment, your milage may vary.

[THEONE]

Yes but ow you will aligned them after ?

Also what exactly is the jig ?

Edited November 15, 2011 by THEONE

[VintageRacer]

@Vintage Racer:

 

can you give a few more details about those MnO2 Motors?

Caliber, Exact formula, Core dimensions?

 

This might be an interesting thing for people who have difficulties in getting proper oxidizers.

 

I'm not able to provide the specifications on the spindle until I get back to it and can do some measuring. It's going to be a long day and evening working but I'll try to get something posted later. The fuel is posted as shown on passfire, Andy H is the author as far as I know.

 

"Manganese Dioxide (ceramic grade): 68

Magnalium (ball milled 6hr..dunno mesh, probably ~500-600): 32

 

Mix with 3% by weight of 5% NC lacquer solution, thinned with additional acetone to fully wet the mix. Then, granulate through 30mesh screen into little ''worms''.

 

What I did was go to the ceramics shop and get a lb of the manganese dioxide. The MgAl I have on hand is labeled as 3µ ( pretty darn fine stuff).

 

These particular rockets are all launched using a soda straw for a launch lug. This MNO2 fuel is not that hot in terms of ISP, same as the BP end burners. So I always

use a lug. This means of course you have to have a wire or guide. That can be as simple as a dowel stuck in the ground, or a piece of piano wire in a board. I have even used

bamboo skewers and left them since they are no harm to the environment.

 

Now, that being said, I'm sure somebody wants to go down the road of " wait, is it a model or a firework since it has fins and is shot from a wire? "

Gee I always hope for nothing to recover, thus meaning they are not intended models. Of course I do experiment with various compositions etc during the day, and in that case I do

try to track and recover the little jewel. It's always a good idea to remove any evidence right?

 

Some put a tube and fins on a motor and fly it from a wire, stand, or stick. Others (myself included) put a stick on a motor and slip that stick in a tube for guidance. I'm not going to argue with anyone on what's what here.

 

The jigs...

 

Many ways to do it or just buy one I guess. I like to make things vs buying. These are just simple plastic tools that help make the process a little easier, quicker.

 

The fins I use are again something I have access too, and make myself. Sure I'd rather use bio-d goods and products (not going to argue with anyone here on the environment, sorry)

but this is what I have and currently use. I use the original super glue to attach the fins. As long as you have a good joint to the tube, and use the glue properly, it holds fine and is much

faster than any other method.

 

Hope this helps some or clears some of the questions.

 

DanB

Edited November 15, 2011 by VintageRacer

[warthog]

When I was still building model rockets, I always used regular Elmer's white glue to attach the fins. Once the initial sticking was dry, I would go back and make fillets along the joint, again with white glue. The only time I ever had a fin come off was when they hit the ground too hard. I never had a fin rip off as the rocket was flying.

 

These little buggers look like fun so maybe I ill finally get myself making rockets starting with these little 4 oz dudes. If it will help, I can post a picture of Dan's tools but I lack a way to make exact type measurements. All I have is a ruler r tape measure.

[stckmndn]

Thanks guys! I think you've covered everything I needed to know to go out and give it a few tries with the 4 oz BP end burners.

 

Also spent some time reading about rocket building and jigs. I can see how that could be a very addicting hobby as well. Didn't realize how much hand craftsmanship goes into those. Wow.

[VintageRacer]

Thanks guys! I think you've covered everything I needed to know to go out and give it a few tries with the 4 oz BP end burners.

 

Also spent some time reading about rocket building and jigs. I can see how that could be a very addicting hobby as well. Didn't realize how much hand craftsmanship goes into those. Wow.

 

Well things didn't go very well for me last night. Had some truck issues when I got to work and dealt with that then worked a while. That put me home too late to do anything.

 

The following is something that you might find very useful. This is the tool I use when thinking of new tooling or having something. It's easy to use, just look the page over and you will figure it out. If you start with a standard rocket type and size, you can then switch it over to "custom" and modify any of the values in each field. I'm not sure if Nicolaj is a member here or not, but be sure to pass on a word of thanks for his program.

 

 

http://www.flashnet.dk/rts/

 

 

The spindle I use for the MNO2 and my short 3-1/2" whistle motors is very similar to a stinger spindle. I'd say it's about 1" long. The end-burners are easy. They are just a little nib of a spindle to build the nozzle around, making a place for the fuse, then flat pressed fuel the rest of the way.

 

With the MNO2 you need a nozzle on a core burner spindle. Though I have not tried, and not seen that anyone else has tried or reported, I don't think an end-burner with this fuel will work very good due to the low power produced. Another note on this fuel. The manganese dioxide will stain your tooling somewhat.

 

DanB

Edited November 16, 2011 by VintageRacer

[TheArchitect23]

I can vouch for VR's jig board. Great quality.

The board has recessed rings that hold the tube, and machined notches to help get you aligned.

Two each ID size. One thin one fat to accommodate assorted wall thickness.