Search found 21 matches

by nils
Tue Dec 05, 2017 7:38 am
Forum: Scratch Built
Topic: basalt fibre - new material for me
Replies: 16
Views: 335

Re: basalt fibre - new material for me

Maybe one day I'll make this kind of "tailcone fins tube launched rocket" and maybe I will use basalt fibre for fins:
Image
by nils
Mon Dec 04, 2017 7:14 pm
Forum: Scratch Built
Topic: basalt fibre - new material for me
Replies: 16
Views: 335

Re: basalt fibre - new material for me

I tried to burn glass and basalt with gas torch. Here are the results:
https://www.youtube.com/watch?v=007KI1q7uWo
by nils
Fri Dec 01, 2017 5:21 pm
Forum: Scratch Built
Topic: basalt fibre - new material for me
Replies: 16
Views: 335

Re: basalt fibre - new material for me

I think I will try this piece of basalt fibre cloth on my next rear ejection rocket.
This fibre itself is much more heat resistant than glass and carbon but can anyone recommend me some very heat resistant epoxy?
by nils
Thu Nov 30, 2017 10:32 pm
Forum: Scratch Built
Topic: basalt fibre - new material for me
Replies: 16
Views: 335

basalt fibre - new material for me

Has anyone here tried basalt fibre instead glass and carbon?
I got a example piece and now I think what to do with it.
I read that it is in use in real spacecrafts but is it somehow usable in hobby rocketry?
by nils
Wed Nov 15, 2017 7:01 pm
Forum: Scratch Built
Topic: bodytube inner surface and ejection charge - heat protection
Replies: 14
Views: 536

Re: bodytube inner surface and ejection charge - heat protection

Yes, I made my own bodytube with polyester resin. Here is a picture of my rocket before the first flight and before 2 successful flights: http://kodu.ut.ee/~nils/source/sugar_rocketry/32/after_before.jpg An area above engine block has turned from half transparent to milky. I made the second picture ...
by nils
Mon Nov 13, 2017 11:47 pm
Forum: Scratch Built
Topic: bodytube inner surface and ejection charge - heat protection
Replies: 14
Views: 536

Re: bodytube inner surface and ejection charge - heat protection

One question about switching from polyester to epoxy:
Polyester does not stick to cooking paper so I can use it as release agent when rolling tubes. Would cooking paper work with epoxy as well or do I absolutely have to switch to some special release agent?
by nils
Mon Nov 13, 2017 8:24 pm
Forum: Scratch Built
Topic: bodytube inner surface and ejection charge - heat protection
Replies: 14
Views: 536

Re: bodytube inner surface and ejection charge - heat protection

One more bad thing I discovered about polyester resin - it becomes sticky when hot. Rocket motor must be very well isolated, otherwise rear ejection does not work.
by nils
Mon Nov 13, 2017 6:09 pm
Forum: Scratch Built
Topic: bodytube inner surface and ejection charge - heat protection
Replies: 14
Views: 536

Re: bodytube inner surface and ejection charge - heat protection

That's what I suspected. I used polyester resin. So I will try to find epoxy for my next rockets.
by nils
Fri Nov 10, 2017 5:51 pm
Forum: Scratch Built
Topic: bodytube inner surface and ejection charge - heat protection
Replies: 14
Views: 536

bodytube inner surface and ejection charge - heat protection

Parachute ejection charge burns a bit my fibreglass bodytube inner surface each time. What would be a good material or a good coat to protect fibreglass inner surface?
by nils
Fri Oct 27, 2017 12:43 am
Forum: How to's
Topic: Attaching shock cord to hollow nose cone
Replies: 10
Views: 1275

Re: Attaching shock cord to hollow nose cone

I have learnt that it is not only the HDPE itself that is unbondable. It is more about that the HDPE details are covered with release agent. It is not possible to clean them just with solvent but with flame treatment + alcohol cleaning. I tested this flame treatment + alcholol cleaning yesterday. I ...
by nils
Wed Oct 25, 2017 8:06 pm
Forum: How to's
Topic: 3D printed parts and files
Replies: 3
Views: 1114

Re: 3D printed parts and files

Nosecone for my 32mm internal diameter bodytube. Makes my rocket unsinkable. Rendered image: http://kodu.ut.ee/~nils/source/sugar_rocketry/3d_printing/32_mm_nosecone/32_mm_nosecone.jpg Source blend file: http://kodu.ut.ee/~nils/source/sugar_rocketry/3d_printing/32_mm_nosecone/32mm_rocket_nosecone.bl...
by nils
Fri Oct 13, 2017 7:48 pm
Forum: Scratch Built
Topic: holes in rocket body tube - how they affect aerodynamics
Replies: 5
Views: 360

Re: holes in rocket body tube - how they affect aerodynamics

Thanks for the answers! I decided to make a door for parachute. Parachute rubber is bonded to the door and then to the inner side of the rocket tube so the rubber works as hinge. Door lock is a piece of tape which is strong enough for flight but is weaker than ejection charge. This rocket is now rea...
by nils
Thu Oct 12, 2017 4:20 am
Forum: Scratch Built
Topic: half DVD fins
Replies: 5
Views: 332

Re: half DVD fins

These fins are very strong and stable when not painted with solvent based paint. Now I tried to use sandpaper to make them matte and visible. 3 and 4 fins version is also very easy to transport on a car rear seat.

krusty wrote:Did you get much/any flutter with the DVDs?

Krusty
by nils
Sat Oct 07, 2017 4:28 am
Forum: Scratch Built
Topic: half DVD fins
Replies: 5
Views: 332

Re: half DVD fins

These half DVD-s were not metallized so I painted them to make them visible. Next time he will bring me metallized ones.
This rocket on the picture is now completely broken. I used a paint that made polycarbonate fins and fibreglass body tube very very weak.
by nils
Sat Oct 07, 2017 4:15 am
Forum: Scratch Built
Topic: holes in rocket body tube - how they affect aerodynamics
Replies: 5
Views: 360

holes in rocket body tube - how they affect aerodynamics

I would like to make 2 elliptical holes in my rocket body tube. One for GoPro Session camera and one for parachute side ejection. I have no idea how much these holes affect rocket aerodynamics and stability. Do I absolutely must make window for camera and door for parachute? Or can I just make holes...

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