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C class rocket - College project

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mattyboi

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Hi, i am new to this forum.
Im studying a BTEC National Diploma in Engineering at Milton Keynes College and im in my final year.

For my final project me and a friend have been given the task of trying to break the UK altitude record for a Class C Model rocket. I thourt it may be an idea to join a forum such as this in hope that somebody may give up some of their own time to have a read and give and suggestions or comments on how i should proceed.

So far i have drawn up all the parts that we will build on a CAD program ready to be built (have 2 styles of nose cone machined so far).
Also have some parts on order from Rocketstore.co.uk which is a 1.1" blue tube, rocket motors, and shock cord etc, unfortunatly this college seems to have a very long order process and we have very little we can do now untill the parts turn up...

We will be making our own launch pad. And are having to fix an old altimeter which we can mount into the rocket.

A few questions i have:
Are there any dates coming up in the next 8 weeks where we will be able to launch?
I have lots of CAD drawings and pictures to show, how do i post them on this forum?

thanks
Matt

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dave carver

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By class "C" do you mean like a C6-7? or a "G" motor that fits your airframe of 1.1 inches?

Insuffecent info to make a call.:cyclops:
 

Peartree

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Some of this may make more sense to the folk from the UK.
 

mattyboi

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Sorry for not being very specific, I mean a c-5 motor size from estes. We will be using centering rings to fit the motor.

I have drawn up a tower launcher and am just waiting for this to be built for me.

At the moment we are just waiting for our parts to arrive still, are looking at ways to fit the altimeter within a compartment below the nose cone.
 

Gillard

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Hi guys
nice to see some student in the UK building rockets.
my students at the moment are building a few rockets that are D clusters and F singke motors for the UKAYRoC competion.

here's a bit of bad news for your esign (sorry)
if you want altitude then you need to reduce drag and mass.

to do this you need to have minimum diameter - so thats an 18mm tube. blue tube 1.1 is too large, too heavy, too expensive, and a massive overkill. for a low power motor.

so first advice, get some bog standard estes type 18mm tube.

next is drag.

three fins, well finished, all edges sanded -not the root edge!
piston or tower launch, as the launch lug will really increase the drag.
stay away from the pointy nose cones (cone shaped) they are great if you are going faster than the speed of sound, but you won't be!
finish the rocket well, no paint, but make sure there are no edges, seams, shoulders that will add to drag. a quick light coat pledge floor wax will make it smoother for not much mass.
The altimeter needs to be small and light, PerfectFlite - Alt15K/WD is a good model, and its not too expensive.

other things to consider is making the nose cone very light, as the cg will be lifted buy the alt mass anyway. the shock cord needs to be as light as posible so kevlar is better than elastic.
as the model will be light you can use a thin mylar streamer for recovery.
you could get really into the design and make you own tube from carbon fibre

you might want to get back on the phone to Richard at rocketstore and talk him through your design. and cancel that blue tube.

feel free to pm me if you need any q's answering.

check out the UKRA website for launch meetings. i fly at midlands rocketry which have a meeting this sunday, we are up the M1 from you, but EARS are closer, they have a launch date on 4/4/10.

good luck
 

Gillard

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quick question, what is the altitude record for a C motor in the UK. there is nothing on the UKRA website - there is for B motors 295m, and D motors 849m but not C

so if this means that its never ben attempted, then congratulations:clap:, you'll get it on your first flight.
 

davel

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What is the "UK altitude record for a Class C Model rocket"? Generally, for maximum altitude you want to have the model minimum diameter and at optimum mass.

A Estes 'C' motor by itself already exceeds optimum mass, so you want the airframe to be as light as possible while maintaining a stable CP/CG relationship.
 

mattyboi

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Thankyou all for you responses.
Our main concern with the smmaller tube is that we will be using a Alt15k/wd altimeter and are worried about how to fit it into a 18mm tube, would a 24mm tube be a better compromise?

We intend to build a tower launcher and are looking at ways to mount the fins to the body to create the least drag, your ideas sound worth a look tho :) our main problem with calling rocketstore is that I don't know if the order has even been sent to them.. The college has a weird ordering system and the order form may not have reached them yet, it also could be with anyone now.. We just have to wait untill our parts turn up..

when were were given the project I belive there was no record set for a class c , hopefuly as long as we reach 160ft our altimeter will work and can set a record.. Does anyone know how to claim the record and what paperwork and stuff we would need to send off and to who? I belive it is UKRA.
 

mattyboi

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The altimeter is broken at the moment, one of our tutors used to fly rockets quite alot and on landing the mass of the battery snapped the holder and detatched it from the altimeter... we will have to try and re solder a battery back onto it, we are currently looking at different ways to do this, we may have it as a remote battery and put it lower down in the rocket and run wires up to the altimeter which will be closer to the nose cone in a seperate payload bay...
 

Gillard

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Thankyou all for you responses.
Our main concern with the smmaller tube is that we will be using a Alt15k/wd altimeter and are worried about how to fit it into a 18mm tube, would a 24mm tube be a better compromise?

We intend to build a tower launcher and are looking at ways to mount the fins to the body to create the least drag, your ideas sound worth a look tho :) our main problem with calling rocketstore is that I don't know if the order has even been sent to them.. The college has a weird ordering system and the order form may not have reached them yet, it also could be with anyone now.. We just have to wait untill our parts turn up..

when were were given the project I belive there was no record set for a class c , hopefuly as long as we reach 160ft our altimeter will work and can set a record.. Does anyone know how to claim the record and what paperwork and stuff we would need to send off and to who? I belive it is UKRA.
i use a Alt15K and it fits into a 18mm tube.
never submitted an altitube record before, but i guess you will need an RSO from UKRA to verify the flight, if you fly at EARS then it won't be a problem as there will be plenty of RSOs around and probably an altitude record holder or two!
 
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