'Mach-Buster' - 24mm

[Karl]

I've took a search through my scrap box and came accross the upersection BT off a Estes Python 4 kit. And ideas just flooded my head
Theres 3 Nosecones I can choose from , the origional Python 4 nosecone ( looks like a small Fatboy NC) , a Patriot style version , or a Black Brant style . I myself think the Black Brant looks awesome !

So I used :

The payload section off the Estes Python 4 kit
1 x 24mm motor tube
1 x Engine hook
1 x BT-50? Black Brant style nosecone.

I chose a sweet style of fins (#3), tacked them to the BT using thick CA , and added fillets with Wood Glue. Then becuase the 24mm motor tube was nealy the same dia of the bodytube , I wraped a few layers of masking tape at the top & bottom of the motor tube. Placed it into the bodytube , glued it in place and added a small fillet of Wood Glue at the aft 'Centering Ring'.
As for finishing , I painted the whole thing in white , matt basecoat & left for 24hours. Then sanded it down to a smooth texture , dusted it off using the air compressor , and sprayed it (+nosecone) using PlastiKote Chrome.

I will post pics when the paint is dry.
I hope to fly it on Saturday (Weather permitting) on D12-5

But before I fly it I want to test it out using a smaller ( 18mm ) motor . I could make 2 x 24mm centering rings using 5mm MDF , with a circle in the middle (19mm) to hold the 18mm motor tube in place. But I think this would be a over-kill , is there any way I could fly it on a 18mm motor without doing this?

Any help will be greatley appreciated.
Karl

 

[Karl]

Just a question for all the Rocsim pro's out there.

Would anyone be kind enough to rocsim her please ? If anyone is interested please pm me and I will PM back with all the needed info.
Cheers
Karl

 

[radiO]

can't wait to see a picture. the black brant NC rules...

 

[OKTurbo]

Karl,

If you have an old Estes 24mm D or E casing, you already have the centering rings necessary to make a 18mm to 24mm adapter. Just get out the hacksaw or razor saw and chop out a couple of rings from the old casing.

....the price is right....FREE...

John

 

[Karl]

Thanks OKTurbo!! Im just about to folow your advice

Ok Ok , heres some a shot of her with the paint drying. Look at that _shine_ After it's dry , It's either another coat of chrome or a coat of clear over the top to keep the chrome effect.

Sorry if you get a white border around the picture , I dont know how to remove that

EDIT :

More & Better pictures when shes ready

 

[GL-P]

How long is she?? The pic is kinda at a weird angle so she looks kinda stubby.

 

[DynaSoar]

Originally posted by Karl
But before I fly it I want to test it out using a smaller ( 18mm ) motor . I could make 2 x 24mm centering rings using 5mm MDF , with a circle in the middle (19mm) to hold the 18mm motor tube in place. But I think this would be a over-kill , is there any way I could fly it on a 18mm motor without doing this?

Build a replaceable adapter.

Since you specify a D12, I'll assume you used a 2.75" engine hook, and that per usual you glued it so 1/4" of the engine would be exposed.

Get a 20/50 engine mount kit plus an extra 20/50 centering ring
(or, 2.75" of BT20, three 20/50 rings, plus engine bock and/or hook)

If you use a hook, insert top end through BT20 at 2.5" from after end and tape/glue in place. And/or glue engine block inside BT20 inserting to 2.5" from aft end.

Slide one centering ring up from aft end to 1/4" from end (rear seal)
Slide second ring behind it, even with aft end. If using a hook, notch this one so hook can spring enough to let mtoor in/out.
Slide third ring down from forward end of BT20, to even with forward end of tube (forward seal and to contact top of main tube engine hook).
Glue all rings in place.

The ring spacing should be such that the end rings are placed exactly where the ends of the 24mm motor would be.

Insert 18mm motor into this, and then this into 24mm motor tube.
If you use a hook on the adapter, make sure they're not lined up, as the notch in the bottom ring would let the adapter slide back under ejection pressure.

If you use a 3.75" (E size) engine hook on the main body, use 3.75" of BT20, still gluing the forward ring even with forward end of BT20.

I've built a bunch of these knowing I'd be building and testing several 24mm birds I wanted to test or fly on 18mm motors (see thread "Flight Of The Sandman"). Note that if you use the 3.75" version, the ejection of the 18mm motor is going to eat up the forward end of the adapter tube pretty quickly; consider these disposable, two uses at most unless you coat the inside of the tube to protect it. The 2.75" version, with an decent engine block (like a slice of empty 18mm motor casing), won't suffer this.

Either way, make several so you'll have them next time you want to test one, or just fly a 24mm bird on, say, an AT D21 S/U.

 

[teflonrocketry1]

I don't think that design is going to be stable unless you add some nose weight!

Bruce S. Levison, NAR #69055

 

[Karl]

Nope me neither , I have some play-dough, will that do with a layer of epoxy over the top to keep it in place?
Karl

 

[BlueNinja]

Take a spent D12, ream out the nozzle about twice its normal dia., insert nozzle up in the rocket, insert your 18mm motor.

 

[Karl]

Right , Im gonna' put her up on a C6-5 at the weekend weather permitting. I think she'll do just fine without noseweight on a C , never the less , Ill swing test her before she flys. I think I'll measure up how much 'Play-Dough' ill need , take it to the launch site and apply it after the C flight. I carn't wait to see her SCREAM on a D12!! I should of added fins like a Thor on there , the whistle would of been awesome......Hey wheres that 3" tube..........

 

[teflonrocketry1]

Originally posted by Karl
Nope me neither , I have some play-dough, will that do with a layer of epoxy over the top to keep it in place?
Karl

Karl,

Post the detailed measurements and I will create and post accurate RockSim file that includes the right weight of clay to use in the nose cone. A .jpg or some other scan file of the fins would also help. Attached is a RockSim version 5 file of what I have so far.

Bruce S. Levison, NAR #69055 Section #535 Tri City Sky Busters

 

[Karl]

Thanks for the Rsim file! I got Rocksim V7 today and made a sim. Here she is........
Wow shes gonna get WAYYYYYY up there!
Karl