Hybrid Whistle - 4oz motors 50/50 benzo and Pine BP

[mkn]

Hi All,

A couple of videos on some fun new motors for me. These are 50/50 benzo and BP as in title, I use my own tooling which is 3.12" for a core. I have Pine BP, tame whistle, and a long core, seems to be a good mix. I caped the motors with 3/4" salicylate whistle for delay.

The first is topped with a 3/4" x 2.5 inch sponge TI snowball report, lots of height , a bit too much for the ipod video

the second is topped with a 3.5 inch ball shell, homemade hemis and a mix of 1/4 - 3/8 " violet ( Veline) stars. I think this one could have used 1" of delay to get a touch more whistle and height.

I like the power of these whistle rockets, and the "whistle" is a plus ! Both are with home rolled tubes, waxed.

a fun set of rockets and my first good snowball report ! ( video does not do justice....we had a great ball and big boom from a tiny 3/4" x 2.5" header.....


Ti Snowball:

3.5 " Ball shell with Violet stars mix 1/4 " to 3/8"

 

 

 

Cheers !

 

Matt

Edited September 9, 2014 by mkn

[Zmuro]

Did you mix two granulated fuels together per weight or volume? Nice rockets by the way.

[mkn]

Hi Zmuro,

 

Thank you for the complements, they are a lot fun these small rockets with lots of lift power !

 

I did weight measurements of BP mill dust and my tame Benzo whistle, mixed in a container by shaking. added increments to top of spindle, then capped with the Salicylate whistle ( also tame).

 

Matt

[Blackthumb]

Love to see pyros experiment!! Way to go MKN!!

[mkn]

Thanks Black Thumb, I had read about it and talked with Nater and Pysco , The long-ish spindle seems to work well with my tame whistle, someday I may try a more pure whistle batch, but these little guys are able to lift most everything I am building now, either the 50/50 mix or straight. I can only imagine the lift capability for my 1# tooling.......... Matt

[schroedinger]

A 3.5 " header on a 1/2" id rocket sounds quite impressive, did you test witch weight your rockets can lift to a safe height?

[mkn]

Hi Schroedinger,

Yes I ran tests with a baseball ( 144g) and a softball ( 190g)

first test was straight salicylate whistle, way too high with a baseball for these shells, 3 - 3.5" 140g - 190g ( when it came down in the field it buried the baseball 2/3 deep)

2nd test was 50 /50 benzo and BP , still seemed too high with a baseball, looked about right with a softball. That is the range I was looking for.

So that is what I used for the 3.5" in the video, 180g ball. What I would try next for that size shell is a 1" delay, as seen in the vid, burn thru seemed early, short whistle and rocket still going up compared to the identical motor with the Ti snowball ( guess the header was 40-50g)

Fuel and delay pressed to 5,500 psi force ( 500 pounds on gauge)

For me this lift capacity is great, most of my ball shells are 3 - 3.5 " for now. Nice mix of fuel used, tube, and stars in the shell, for a good size display


I do have my sights on the infamous "4 on a 4" ( 4oz + 4 " ball ) I will need to run weight tests for 280 - 330 g seems that is what my 4" ball shells weigh.


Question - for delay tests, with dummy weight, should I pack a report in the end of the rocket to know precisely when the burn thru happens? I can see a puff, but that maybe be slightly after first fire burns thru.


I tested my 1# tooling I made with straight BP, lifted 520g header and 50 g of sticks to a good 3" height - so now to test for a 4" weight, and someday when I build a 5" weight.

 

Matt

[schroedinger]

Ty for that answer. That are nice weights you can lift with your rockets. I gues the 520g where nozzleless made with fast fuel?

 

For a test rocket i always used a sand bag header with a smal report (1g) and a delay with is about double the delay i would use normally. This way the rocket can arch over and you can tell easy how long your delay needs to be. Also the report in the sand bags greatly decreases the rocket weight during fall back.

[mkn]

Yes, 520g was straight BP + mineral oil hand rammed and bottom lit.

 

 

I like the sand bag idea, just a heavy duty plastic bag with the fused report inside to pop the bag?

 

That would be quite handy, the 520g was a peanut butter plastic jar full with water, buried that half way up the jar in the woods on the field edge....

 

 

I don't quite follow the double delay and arching of the rocket at apex, from that how are you able to determine the correct amount of delay?

 

Thanks Matt

[schroedinger]

No plastic use kraft paper or paper roll bag. I hate plastic in the enviroment.

 

Record the flight (if you got problems with that attach a smoke comet (day) or a an easy to trac comet like e.g. a blue one) on camera.

 

Now you take the time between the report popping (the picture not sound) and the top point of the flight, make up a 2nd rocket with a delay shortened for this time and test again. Most times you are now in a range of about 0.5 secs witch need to be adjusted and got the delay dialed to the right timing by using 2 or 3 test rockets.

[FlaMtnBkr]

the 520g was a peanut butter plastic jar full with water, buried that half way up the jar in the woods on the field edge....

 

I'm really confused by this

[wildcherryxoxo]

I'm really confused by this

 

 

You and me both!

[Mumbles]

I took it to mean that the weight he used was a peanut butter jar filled with water, which weighed 520g. After launching and subsequent return to earth, it buried itself (the jar) halfway into the ground.

[schroedinger]

I think so too, just one thought while imaging that: Incomming!

[mkn]

I took it to mean that the weight he used was a peanut butter jar filled with water, which weighed 520g. After launching and subsequent return to earth, it buried itself (the jar) halfway into the ground.

You got it mumbles

 

I think so too, just one thought while imaging that: Incomming!

Yes they are launched in an empty field.

[mkn]

No plastic use kraft paper or paper roll bag. I hate plastic in the enviroment.

 

Record the flight (if you got problems with that attach a smoke comet (day) or a an easy to trac comet like e.g. a blue one) on camera.

 

Now you take the time between the report popping (the picture not sound) and the top point of the flight, make up a 2nd rocket with a delay shortened for this time and test again. Most times you are now in a range of about 0.5 secs witch need to be adjusted and got the delay dialed to the right timing by using 2 or 3 test rockets.

Thank you, I understand take the total time your delay is burning in the video, convert that to fractions of an inch or MM of delay comp, subtract the amount of over delay recorded on the video.

 

Any chance you have a pic of the construction of the paper sand bag? I would like to try that, seems it would have to be quite sturdy, the 1 gram of report is able to beak it because it is tight construction - no air pockets- and the gases must rupture the paper to escape ?

 

I don't like the plastic either, I imagined the ruptured bag would still be attached to the rocket, which would be retrieved after launch and disposed of.

Matt

[schroedinger]

Start constructing the bag just like a normal cylinder shell.

If you make 'em big like your describe, use two end disks.

Roll the casing out of recycled kraft whith a god ammount of thick dextrin glue. 3-4 turns are god enough. Insert the bottomdisc either way by pleating or slicing method. Add 2nd disc, punch a fuse hole and insert the shot. Now fill the casing with the sand. For closing up, lay a clove hitch knot around the excess paper and crimp it shut. Use a quite thin cotton string for crimping, about 1mm diameter is good.Then set aside to dry

 

If you use a sand load with 500g it is propably better to go up to 3g of vitamin f or just spike the 1g with about 5g of 2fg bp, you dont want to blast the header into hundred of bits, you only want to open the header on the front and eject most of the sand, this help with seing when it poops. The sand left over in the open header will fall out during comeback.

 

The opening direction of the header is specially interesting on the second flight, as it shows you, wheter the rocket allready arched over or net. (If you cant see a direction then the walls bursted as the sand confined enough, this happens but is no problem).

If you want to spare the vitamin f, fill the header with about 10g of bp in a flat paper (plastic works to ofc) sandwhich bag, insert a tight disc and drop in the sand over that. Crimp shut.

In the end you get a "aerial mine".

[mkn]

Perfect ! Thank you for explaining, I will definitely start employing these tips. ( I had better dig a bucket of sand before we freeze over in the coming months)

 

Now that seems so simple after you explained it. " why didn't I think of that "

 

 

As a newbe, is there an area in the forum that these directions can be posted for new rocketeers ? Maybe they are somewhere I just did not come across them.

I have struggled finding various weights to attach for lift test, never being able to dial the correct weight I wanted, rather what ever weight the container I had held with flour, or water, I've sent golf balls, added quarters for more weight. Now the weight can be dialed to grains of sand, and the visual is there for burst timing !

 

 

I see a 350g "sand canister" in my near future , to prep for that " 4 on a 4"..........

 

 

Matt

[schroedinger]

Well we still got the tutorials section.

[FlaMtnBkr]

When dialing in motors it is fairly common to make a shell like you plan on using and adding an inert filler to achieve the weight of the real shell. For smaller shells it may be something more dense like sand or gravel and larger shells something more like dog food.

 

A break charge such as a flash bag is a good idea and will still give input on timing.

[WonderBoy]

That's a nice little motor!

 

Are you going nozzleless with that 50:50 mix? I'll have to measure my spindle, but I run straight benz whistle on it without a problem and it easily lifts a 4" ball.

 

Also, if you're testing in the day time, you can fill your cylinder with line chalk to give a nice color smoke cloud.

 

 

WB

Edited September 12, 2014 by WonderBoy

[dagabu]

I missed something, you guys lift 4" ball shells on 1/2" ID motors?

[Maserface]

well,... yes... but at some point in this thread the OP switched to 3/4" motors.

 

Edit: I guess both at this point, this thread is pretty hard to read.

Edited September 12, 2014 by Maserface

[dagabu]

well,... yes... but at some point in this thread the OP switched to 3/4" motors.

 

Edit: I guess both at this point, this thread is pretty hard to read.

 

Gotcha! Thanks, I thought you guys had punched a hole right through the 1/2" ceiling!

[schroedinger]

Sry dag to disapoint you, but have a look at post #7.

The 19 mm rocket was just about 520 g tested.

 

In post one he shows a movie about a 12.7 mm rocket with a 3.5" header and now he is aiming for lifting a 4" on a 4 oz.