Nozzleless BP rockets

[dangerousamateur]

I'd like to know what are your experiences with nozzleless.

 

I've got a 14mm caliber tooling here.

NO ballmill, just wetmixed 75/15/10, now i use 62/28/10 with nozzle.

 

 

Considering that almost all my rockets I was able to find afterwards had lost their nozzles, I can even claim to have some experience with nozzleless - good start and then a little lazy, a normal coreburner makes more trust as the burn progresses.

 

With the Propellant extented over the nozzle section and much hotter fuel I expect to get more trust - what do you think?

Edited September 25, 2011 by dangerousamateur

[allrocketspsl]

I'd like to know what are your experiences with nozzleless.

 

I've got a 14mm caliber tooling here.

NO ballmill, just wetmixed 75/15/10, now i use 62/28/10 with nozzle.

 

 

Considering that almost all my rockets I was able to find afterwards had lost their nozzles, I can even claim to have some experience with nozzleless - good start and then a little lazy, a normal coreburner makes more trust as the burn progresses.

 

With the Propellant extented over the nozzle section and much hotter fuel I expect to get more trust - what do you think?

 

now here is where the main man,not me opines, for the record I shot my first last night with small report to test the delay,take off was quite unexpected since I have always done cored. I fused it bent visco instead or top core which is how I fuse all my cored rockets.BP is 75/15(airfloat 50 coarse hardwood 50)/10 screened and wetted then granulated once.Didnt seem to have alot of power so since i have no ball mill I shall stick to cored! I will use nozzeless for large reports in the future. Good luck So yes you can make them without a ball mill!!!!

[Peret]

I'm reviving this fossil thread, rather than starting a new one with the same title. How does a nozzle-less compare with a nozzle for BP rockets? Does anyone actually have an ANSWER? I've already spent far too much time searching the archive threads on various forums and coming up with not much more than what Allrockets said above, or along the lines of "my nozzle-less end burner can lift a 4 inch shell". Big deal. So, you rocket guys, put the cookies down and spill. Has anyone done any convincing comparative tests, like on a rocket test stand?

 

<edit> INCENTIVE

 

Coming soon: the Acme Rocket Thrust Integrated System Tester (ARTIST), from Peret Productions. Helpful people may be sent a sample to evaluate.

Edited March 21, 2012 by Peret

[californiapyro]

I swear i've seen a thrust curve graph before! but for the life of me i can't find it right now. the gist of it was nozzleless have more thrust for a shorter amount of time, with peak thrust at takeoff, while nozzled have less thrust for a longer time with peak thrust right before the delay kicks in. hopefully someone has the graphs

[nater]

Some people on passfire have made thrust curves for all the different rockets. I have a test stand in the works, but it is not high on my priorities. I have the parts for an amp, but I still need to buy a load cell, a device to convert the amplified output from the cell so a computer can use it, as well as fashion the stand itself.

[dagabu]

Search for "thrust curve" in rockets section at Passfire. Dan and Ned have posted several of them.

 

-dag

[Peret]

Search for "thrust curve" in rockets section at Passfire. Dan and Ned have posted several of them.

Indeed they have, in the test stand thread, but nothing useful that compares like with like. There is a thread on "nozzled or nozzleless" where Ned says nozzleless with standard tooling is double the thrust of nozzled with UT tooling, using different fuels, but that's not an answer and besides, there are no numbers or curves. It's a simple question I want answered - using the same spindle, and the same fuel, what's the difference between nozzle and no nozzle?

 

Some people on passfire have made thrust curves for all the different rockets. I have a test stand in the works, but it is not high on my priorities. I have the parts for an amp, but I still need to buy a load cell, a device to convert the amplified output from the cell so a computer can use it, as well as fashion the stand itself.

My thrust stand design is well advanced, and I'm going to do my own tests. If you wait a bit I'll publish the specs and drawings.

[californiapyro]

well, if you use the same fuel one of the rockets won't work. nozzleless really should be as hot a fuel as you can make.

[nater]

for what it is worth, I have flown rockets with the same fuel, same spindle, same ramming technique, same fusing, and built on the same day. Nozzless was sluggish, slow to lift off and slow to reach peak. It probably would not have carried any weight. With a nozzle, flights were fast, high, and straight. I could easily conclude that nozzless bp core burners have much lower thrust than nozzled, all else being equal. The trick is builders are using a much hotter fuel in nozzless rockets to acheive good flights. The hot fuel will cause a CATO with a nozzle.

[Peret]

Using hotter fuel doesn't tell you the difference between nozzle and no nozzle, it tells you the difference between nozzle with fuel A and no nozzle with fuel B. You can't determine the nozzle effect unless you actually measure nozzle and no nozzle with the same fuel. I'm quite prepared to learn that one won't lift, that's not the point. Is it half as much thrust, a quarter as much? A tenth? And what's the shape of the curve, is the peak thrust at the beginning or the end?

 

I can see there's a scientific paper and possibly a Nobel Prize in this research project. I wonder if I could get a grant for it if I said it was to investigate global warming.

[dagabu]

for what it is worth, I have flown rockets with the same fuel, same spindle, same ramming technique, same fusing, and built on the same day. Nozzless was sluggish, slow to lift off and slow to reach peak. It probably would not have carried any weight. With a nozzle, flights were fast, high, and straight. I could easily conclude that nozzless bp core burners have much lower thrust than nozzled, all else being equal. The trick is builders are using a much hotter fuel in nozzless rockets to acheive good flights. The hot fuel will cause a CATO with a nozzle.

 

I know I just addressed this last month but the nozzleless rocket is fully dependent on the placement of the ignition to make more thrust then a nozzled rocket. I have a couple test ideas that I hopefully will try next weekend where an e-match will be piped all the way up to the end of the core and held in place with a wad of cotton. I fully expect it to CATO but if it does fly, I fully expect it to take off like a whistle motor.

 

I have a #70 postal scale I will be video taping as well to do a quick and dirty test for peak thrust on some motors and if I have time, I will make another nozzleless to test if the first one does not CATO and will test a conventional BP motor (same exact fuel and tooling) as well to get a more definitive answer.

 

Anyone want to see that?

 

-dag

[Peret]

I would like to see it. Only by getting some comparable test data can we ever arrive at a proper set of design rules. This is real rocket science

[Mumbles]

I agree those would be good tests to see. I'd also be interesting to see what is capable with a red lined rocket of each type. Fuel optimized for each variety.

[dagabu]

I agree those would be good tests to see. I'd also be interesting to see what is capable with a red lined rocket of each type. Fuel optimized for each variety.

 

I will be using the identical fuel in both of these rockets to get a base line, straight 116 Fuse powder, no additives. I believe the optimized fuels have already been chosen though, hot whistle for the nozzleless and 75:15:10 for the nozzled. I cant think of hotter fuels that will not cross the red line.

 

-dag

[FlaMtnBkr]

I like nozzle-less rockets best for what that's worth. I don't have to mess with clay and worry about erosion or grog that can damage the tooling. I also don't have to tune the fuel and worry if each batch of fuel might be too hot. I really consider nozzle-less as BP rockets since whistle has to be nozzle-less if it is to whistle. So I make the hottest BP that I can make, add a little charcoal or metal and rice it through a screen. I don't use a binder and the BP is sturdy enough.

 

I don't lift big shells but from my research the nozzle-less will lift quite a bit more weight than a conventional rocket. That is hearsay and I don't have numbers and proof but the way a NL takes off I believe it. But the simplicity and how easy they are to make is why I like them. Since I don't lift big shells I frequently use my hot BP for the cores section and put whistle as the delay. It uses less whistle fuel and gives a different effect to a BP rocket.

[dagabu]

I will be using the identical fuel in both of these rockets to get a base line, straight 116 Fuse powder, no additives. I believe the optimized fuels have already been chosen though, hot whistle for the nozzleless and 75:15:10 for the nozzled. I cant think of hotter fuels that will not cross the red line.

 

-dag

 

I will have to delay the tests, can't go the the test site this weekend

 

-dag

[dangerousamateur]

I've got another question:

 

How do you light your nozzleless motors - at the "nozzle" or at the end of the spindle?

[dan999ification]

At the top, if they Cato light half way up or add more oil.

 

The core must light before the throat erodes too much, otherwise you get lower or nearly no thrust and erratic flights.

This one needed some more delay.

http://youtu.be/ZcbtWwk1Asw

 

Dan.

Edited April 22, 2013 by dan999ification

[Bobosan]

Here is a cored 2oz nozzless without bulkhead and 3 smoke cracker header. The header doesn't show well since I had the top end capped which didn't allow airflow through tube. Last puff of smoke was header. Visco inserted all the way up to delay.

 

http://youtu.be/1mlYgXdF1nw

[dangerousamateur]

Nice rockets. Cant see any red smoke though.

 

I finally shot two, but I was not pleased with their power and they where lit at the nozzle.

I'll try topfusing next time.

 

I thought BP takes fire so easily that it wont matter where i light it.

[dan999ification]

If you light at the nozzle it erodes and will not get full power, it's also hard for the flame to pass to the top of the core since it wants to burn out from it. With a nozzle there is still a difference but the nozzle gives enough back pressure to allow the grain to light quicker and it also stays in tact helping with the thrust.

Imagine the throat on a nzless rocket as the nozzle itself, you want it there for as long as possible before the grain burns out to maximise power.

[Bobosan]

Nice rockets. Cant see any red smoke though.

 

 

It looked red to the eye but showed up as a white trail on video. They were just cheap smoke crackers.

 

I carefully insert the fuse until it stops (hopefully at top of core). Friction fit holds it in place.

[dan999ification]

Do you secure it with a nosing? I use a 5mm paper pipe, 2 turns of thin craft and 3 strands of bm.

Piping the match guarantees the nozzle area does not take fire before the top of the core is lit.

 

Dan.

[Bobosan]

If transporting or storing I'll tape fuse to stick and add the noseing. Usually firing shortly after building.

 

Haven't worked with black match or piping yet. Visco for now but guess piping would work there too with a small diameter visco.

[dagabu]

Depending on the kind of visco, it can burn through the piping and light the rocket too early. Chinese visco will in fact burn through metallic tape like that used for HVAC while a few turns of kraft tape (masking tape) seems to hold up to the flame very well.

 

I agree with Dan that a nosing can really save the day.