Deep Purple by Misha Rocketry Build Thread

I feel bad now, that was just a joke, I spent 3 hours measuring and re-measuring, then epoxied, and then dry fitted the fins to make sure it was all good.
Here it is left overnight with the fins in place.

Hi Simon, looks like a sweet build. Where are you launching this? Love to see it disappear(!) if it isn't too far from me (Cambridgeshire, UK)

Hi amell,

I hope to launch it at Black Knights next Sunday which is about 100 miles from Cambridge. But since there seems to be some interest from the guys at EARS, I might pop along there for a launch too. I'll be launching on small motors single deploy initially, probably to 2.5k max, and wait for a really good day with minimal breeze and no cloud for higher launches.

Anyway, on with the build.

I decided to use Kevlar as an initial shock cord and JB Weld it to the motor tube. I drilled out a hole in the centering ring, then threaded the kevlar through. This is 3/8 inch tubular kevlar, should be easily strong enough.

Now I've got a 5-6 hour wait for that to go off enough, then I'll epoxy the motor assembly and the fins simultaneously to the air frame.



Cutting down the coupler for the nose cone, I did this by hand with a hack saw in the end, only took a few minutes.

Other side of Kevlar attached to motor assembly

Motor assembly is in and fins are on. Not taped too tight as I don't to squeeze all the epoxy out of the joins.

I'll be doing the fin fillets next week, 8 fillets to do, so I'll do 2 per day and have it finished by Thursday.

Here it is so far



And with me standing next to it for scale, I'm 6' 3"



I think it's the nicest looking rocket I've ever built. When I asked my wife what she thought of it her comment was "I like those little fins, you've never done that before". Don't know why I bothered asking

Sorry I misquoted my wife, what she actually said was "I like those little things sticking out of it, you've never done that before".
Of course I have (3 in fact), she just doesn't pay much attention to my rockets.

Nice and shiny. No need for paint with this! How heavy is it right now?

It's a few grams under 4kg or 8.8 lbs. I reckon with 'chutes and cords etc it should be about 4.5kg or 9.9lbs max.
A lot of that is the AV bay which comes in at 750g, but I think it needs it to keep the CG higher up the rocket.

Awesome kit!

Mark

Well I didn't launch today due to bad weather. But the good news is that I passed my Level 2 exam instead, and am looking at launching on either a CTI J210 2 grain Classic or a J380 3 grain SS (both 54mm), I'll probably go with the J380, I don't have a rocksim file yet, but I reckon it'll be about 3,000-3,5000 ft as a guess, so not spectacular, but a good solid Level 2 attempt. I am resisting the temptation to go bigger but I did buy a 54mm six grain case today just in case, so the option is there. I guess I just need to be sensible for once. The next launch date is 21st December. Hmm a K660 6 grain classic looks good too. Decisions, decisions.

On reflection, it has to be the K660, I bought the case in full knowledge of what I really want to do, if you're gonna do something, do it in style. Video to follow, weather dependent of course.

K660 on a CF airframe that size? Good luck finding it! Have you a radio tracker or something like that?

Was going to go to Midland Sky today but it was thick fog this morning so I cried off. Looks like wont be able to launch anything until March now.

I also bought one of these https://www.amazon.co.uk/dp/B00MCINE88/?tag=skimlinks_replacement-20
it's pretty cool, you just phone it and it sends back a text with a url for google maps with it's location on it. It'll only start working on ejection because of the CF, but that's OK, I just need to know the location on the ground.

Change of plan, going all out, and hopefully sail through Mach 1 while getting my level 2. All or bust

Simon said:

I also bought one of these https://www.amazon.co.uk/dp/B00MCINE88/?tag=skimlinks_replacement-20
it's pretty cool, you just phone it and it sends back a text with a url for google maps with it's location on it. It'll only start working on ejection because of the CF, but that's OK, I just need to know the location on the ground.

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If it can get a signal where it lands. I'd try to get a fix on it when it's still in the air, just in case.

Damn! That should be pretty spectacular. If weather is good I will try and get there for the launch!

Misha2k1m said:

Do you use Rocksim? I can send you the design file so you can simulate your launches/motors.
If not, tell me which motor you will be using and I will send you the results of the Sims

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How high does a K1440 sim out at??

Hi amell,
May be doing at at EARS on 7th December. I'll keep you posted. I just can't wait, I'm just soooo excited it'll be my first K launch. I think I whinged earlier about losing my rockets, guess I've only got myself to blame, I just can't resist sticking the biggest motor possible in them.
It sims at approx 8,500 feet, and 1,250 fps so well over Mach 1. Not too high, a good chance of getting it back, getting it back intact is another matter
Sim file isn't complete yet, this is an approximation. Still need to tweak it a little, but these are pretty good ball park figures.

Unfortunately I can't make the December EARS due to family commitments.

If you launch at EARS make sure you check mobile coverage for the SIM you use in the GPS. The area a mile or two to the west of the launch site (Papworth) has non-existent mobile coverage on at least 3 and T-mobile networks. I live a mile from EARS.

Would hate for you to lose such a nice looker

I've got a Vodafone SIM in it, is that any good there?

Simon said:

I've got a Vodafone SIM in it, is that any good there?

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I don't know about that one - I don't have anything on Vodafone now. When I tried this a few years back it wasn't brilliant. Check their coverage map.

It'll be the 21st December at Black Knights, we are getting the word out for people to come along (expand the UKRA membership beyond 84), hope you can make it amell.

Simon said:

It'll be the 21st December at Black Knights

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Great. I will be there, weather pending!

Simon said:

Change of plan, going all out, and hopefully sail through Mach 1 while getting my level 2. All or bust

View attachment 246859

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I saw that motor in action last year... You won't be disappointed!

While I wait to launch I thought I'd share some photos of the giant AV bay with the tiny Raven altimeter. You'll notice it has nylon screws and is raised up. This is because the attachment points of a Raven have power and CF conducts it.

Here is me testing that the magnet would see through the CF and power up the altimeter

[video=youtube_share;20Vyc9i5f3s]https://youtu.be/20Vyc9i5f3s[/video]

It works

This is the reason why I put the altimeter on the outside of the AV bay, I may back it up with an RDAS if I have the time.

Looks good! That av bay really needs something else in it. A hamster strapped to a flight seat?

When do you think your next launch opportunity will be?

Simon said:

Change of plan, going all out, and hopefully sail through Mach 1 while getting my level 2. All or bust

View attachment 246859

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Simon could you measure how long that reloading packing is please. Want to check it'll fit my new ammo box.

Did you get too fly? My tracker is on O2. Yet to have problem with lack of signal.