M-4000 Sugar Rocket

Hi guys

Here is my latest project. It's a 100mm minimum diameter, all aluminium rocket. Rocket motor is 100mm diameter, 10000Ns KN-Dextrose. Propellant weight is 7,8kg (17,2lbs). Launch weight is 20,0kg (44lbs). Max. altitude will be around 5000m (16400feet). It will have dual deployment recovery- G-Wiz LC Deluxe 800 and timer for backup. This will be my first M powered rocket launch. I hope it works out.

Cheers
Andre

Fins are welded on I presume? If so, what material composition, (e.g.) 6061 t6?

Yes, fins are TIG welded on the fin can. Aluminium is 6082-T6 alloy.

Originally posted by Andre
Hi guys

Here is my latest project. It's a 100mm minimum diameter, all aluminium rocket. Rocket motor is 100mm diameter, 10000Ns KN-Dextrose. Propellant weight is 7,8kg (17,2lbs). Launch weight is 20,0kg (44lbs). Max. altitude will be around 5000m (16400feet). It will have dual deployment recovery- G-Wiz LC Deluxe 800 and timer for backup. This will be my first M powered rocket launch. I hope it works out.

Cheers
Andre

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Absolutely beautiful Andre!!!

We must have launch pics...

(chuckles) Me like shiny nose cone...
Reed

A man after my own heart; an all aluminum rocket!!
I am so tickled pink.
And so completely jelous.
What is the wall thickness of the body tube and how thick are the fins?
I learned to TIG a little over a year ago and would love to make an all AL rocket.
People in the US are a bit skiddish about it however.

Anyway, good luck and let us know how it goes.

Greg

I agree with 11Bravo. Alot of people choose not to TIG and instead bolt them on.

however, you've sure got a nice looking rocket there, good luck with the flight!

yes those flight pics would be awsome
thats a completely amazing rocket
good luck on the flight

Very nice, launch pics are a must!

VERY nice - looks incredible.

Hope everything goes well, and definitely pics
(and vid if you can)

Andre,
When welding the fins to the airframe, did you need to fixture the fin can so that it wouldn't distort? Some sort of a heavy coupler inside the can so, to speak?

Originally posted by 11Bravo
What is the wall thickness of the body tube and how thick are the fins?
I

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Lower body tube is actually motor casing. It's wall thickness is 3,0mm. Threads are machined on both ends of casing. Then the fin can is screwed on one end and coupler on the other end. Fin can wall thickness is 5,0mm. Fins are 4,0mm thick. They were cut with an abrasive water jet machine. Upper body tube wall thickness is 1,5mm.

Originally posted by Stones
Andre,
When welding the fins to the airframe, did you need to fixture the fin can so that it wouldn't distort? Some sort of a heavy coupler inside the can so, to speak?

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No, no fixture was needed. Fin can wall thickness is 5,0mm and fins are 4,0mm thick so there was no problem. With modern TIG welding machine you can weld aluminium sheets no more than 0,8mm thick (0,03inches).

Originally posted by Andre
...
With modern TIG welding machine you can weld aluminium sheets no more than 0,8mm thick (0,03inches).

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I use a Miller 350 Synchrowave w/ cooler and have to test out every now and then with .030 aluminum, stainless , and 4130. Not my favorite thing to do.
I didn't realize the airframe was that thick. I've thought about doing one out of .065/6061- T6. The nose cone, is that turned or is it machined as a billet piece?

Originally posted by Stones
The nose cone, is that turned or is it machined as a billet piece? [/B]

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Nose cone was turned on a CNC lathe out of solid block of aluminium. But this nose cone is not gona fly. It was used to make silicon rubber mold. Flight version will be cast out of epoxy resin and fiberglass. Location transmiter will be in the nose cone so it has to be RF transparent.

I like it, and have thought of doing similar things....but I thought it was illegal to make a metal rocket!?
(That's why I haven't!)

Wouldn't it show up on Radar?

I don't know what makes you think that rockets made of metal are illegal. Yes it would show up on radar. As far as I know every metalic object ,that is longer than the wavelenght of radar beam (a couple of centimeters) will be detected. That of course also depends on the distance from the radar and power output of radar beam.

you gotta notify/get premission from the f.a.a. before you fly anything over 1lb, for the people with the radar would know it was coming...

and the nar dose say to use minimal metal in my rockets. but they are refering to low/mid power. nothing to do with high power/ experemental.


by the way nice rocket. dont blink or youll miss it....

If you look at his location he's in Slovenia....

I want to hear about the launch! I've made sugar motors - I got an M-2000 once - it was sure a fast motor. I remember a basketball sized fireball come out of the nozzle.


Congrats!



Edward

I've made sugar motors - I got an M-2000 once - it was sure a fast motor. I remember a basketball sized fireball come out of the nozzle.

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I've been talking to a bloke in Western Australia who makes his own motors but he told me that you don't get a lot of flame nor a loud sound from Sugar based motors but a lot of smoke does spew out.

I suppose it depends of the recipe used as I'd imagine there are about as many different ways to make them as you can think off!?

I've been reading Richard Nakkas site and am about to embark on some motor building.

What's the best for flame? and or loudness Do you have a recommended motor building site?

if you get any flame in sugar motors it's due to an inefficient combustion, aka propellant burning outside the motor. I however do have to disagree that they're not very loud...I've seen sugar motors that come close to rivaling APCP. they're not quite as loud, but they're sure impressive. good luck.

Flames are not as pronounced in sugar motors, due mainly to particular matter (i.e., K2CO3) in exhaust. This solid component also lowers the Isp compared to that of AP, AN and other propellants having only gas combustion products.

Flames are still visible - I've attached a still frame from a video of a recent burn. This was a KnSu motor (65/35 composition) in a 38mm/360 case that was an H270. It's impulse was 170 N-s and it made more than a little noise.

Sugar motors are a lot of fun to make. I made my first one about 3 years ago and thought I might move on to other propellants. I still enjoy the heck out of making the sugar motors.


John

Originally posted by Nate
if you get any flame in sugar motors it's due to an inefficient combustion, aka propellant burning outside the motor. I however do have to disagree that they're not very loud...I've seen sugar motors that come close to rivaling APCP. they're not quite as loud, but they're sure impressive. good luck.

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Ed's wasn't that efficient anyways - it was VASTLY underexpanded. Looked cool though

Did you ever see the video CJ?

Edward

Yep.
That really was an unusual flame it produced.
https://putfile.com/pic.php?pic=12/33617275288.jpg&s=x11
That's a frame capture from the vid that I tweaked to show the flame a bit better.

Though mine was 54mm too

Edward

very cool looking rocket Andre, good luck on the flight.

Don't forget launch pics and videos

I know this is off-topic and apologies in advance if this hijacks the thread but it relates to sugar motors in general.

Ed and CJ, impressive picture of the 54 mm motor. I have a few questions: What was your expansion ratio and what type of nozzle did you use? The bell-shaped exhaust plume shows classic underexpansion shape and I'd guess the expasion ratio was on the order of 2. For the 38 mm motor I posted, the expansion ratio was 6.5 and the shape of the exhaust plume showed near optimal expasion and no mach diamonds. The Isp calculated was over 130 s. I found shooting video in low light conditions with a dark background helps to increase the contrast in looking at the exhaust plume.

Using sugar propellants necessitates lower Kn values (or larger throats) than most commercial propellants. Drilling out phenolic nozzles from commercial reload (already underexpanded) leads to lost efficiency.

Just interested in how others build their motors.
Thanks,
John

Originally posted by jwagner61

Using sugar propellants necessitates lower Kn values (or larger throats) than most commercial propellants.

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not necessarily true. my favorite Knsu propellant runs at a kn of around 400 and I've never had any probelms with over pressure. I've also gotten ISP's of around 150 or so in an optimal motor. I can't tell you the formula here without violating forum rules, but I can assure you, it's frickin' cool

Commercial solid propellants have actual Isp’s between170 and 250s. (https://www.hq.nasa.gov/office/pao/History/conghand/propelnt.htm)

Theoretical Isp’s of sugar propellants are ~160 s with actual values being closer to 130 s, substantially less than commercial propellants. A key limitation is K2CO3 as a combustion product. Unlike gas combustion products, it’s thermal energy cannot be converted to kinetic by the free expansion in the nozzle. You can’t get around thermodynamics – with other factors being equal, any propellant with solid combustion products will have a lower Isp than propellants without.

My understanding is this is the main reason why ammonium perchlorates and ammonium nitrates have higher Isp's than potassium nitrates.

John