Fliskit Corona 18mm to 24mm interchangable?

[scadaman29325]

I want to build my Corona so that it can take an 18mm or 24 mm engine.

Since the Corona has the OD of .976" (bt50) and it comes with the standard components to build it as an 18mm rocket (two CR50-20, BT20 motor tube, BT20 engine block). I'm thinking all I'll need is a 4" piece of BT50 coupler tube and a 24mm engine block (cut from a spent motor).

Proposed proceedure:

Glue the 24mm engine block in the main tube so that an E engine protrudes about 1/4". (I can use tape to hold the motor in place.)

Mount the 18mm components inside the BT50 coupler. (Realizing that some parts will require sanding for proper fit!)

This should allow the adapter to slip in and out, again it can use tape as motormount/motor retention.

I know this is simple (?) stuff, and I'm thinking this should work, but I've never done it before and once you glue it in...

Thanks in advance for the input!

 

[adrian]

The first question is whether or not the Corona will be stable with the extra mass of an E9 in the back. You may need to add additional nose weight.

Otherwise, yes, that ought to work. Also, get a spent 24mm motor and cut a piece off the casing equal in length to the difference between an E9 and a D12 (1", or 25mm). This can act as a spacer - put it into the Corona, then put a live D12 behind it. Then you can fly it on anything from A to E class.

Another way to make an adaptor is to simply knock the nozzle out of a used E9. An 18mm motor will fit nicely inside the casing of a 24mm motor. Cut about 1/2" from the front of a used 18mm motor to use as a thrust ring. This adaptor is heavier but easier to make than yours - being lazy, I've used this sort of adaptor on several rockets. (Similarly, a 13mm motor fits nicely inside an 18mm casing. I've used that sort of adaptor, too. )

 

[JRThro]

scadaman and adrian, both of those sound like really good ideas to me. I've been thinking/wondering about a simple motor adaptor scheme.

Thanks!

 

[cls]

... whether or not the Corona will be stable with the extra mass of an E9

a quick trip to EMRR for the rocksim file, pop a virtual E9 in ... voila, unstable.

Rocksim says 15 to 20 grams added to the nose cone ought to work ... 750 meters on E9-8, ahhhh much better.

enjoy and good luck getting it back!

 

[lalligood]

Nice choice in choosing to upgrade the motor mount...

I'm pretty sure that an an alternate method of increasing altitude with the Corona is to CHAD stage 2 18mm motors (like a C6-0 -> C6-7) Regardless of how you add more power, the small fins plus the ring fin should be plenty robust for almost anything you can put in it!

Hope you have a nice, big, open field!

(And please share pictures of the build! )

 

[scadaman29325]

Originally posted by cls
a quick trip to EMRR for the rocksim file, pop a virtual E9 in ... voila, unstable.

Rocksim says 15 to 20 grams added to the nose cone ought to work ... 750 meters on E9-8, ahhhh much better.

enjoy and good luck getting it back!

OMG! I've got to learn how to use RocSim.

 

[Justin Horne]

Originally posted by scadaman29325
OMG! I've got to learn how to use RocSim.

Yep. Expensive at first, but very useful...

 

[sveinbjorn]

Originally posted by Justin Horne
Yep. Expensive at first, but very useful...

I know Rocsim is much more in depth for design and such than SpaceCAD, but does SpaceCAD work good for stability calculations?

 

[jflis]

Another easy way to confirm stability is to install the 18mm motor mount with a C6-5 motor and locate the CG. Then remove that motor and mount and install the other mount with an E9-6. Then add enough nose weight to bring the CG back to the original location.

Sounds like a cool modification. If you do this and it works well, consider adding this to the EMRR list of reviews.

Also, this model does well CHAD staged

Also, watch for a 2-stage version or upgrade to the Corona next year

jim

 

[Justin]

That thing is gonna be cool-

You guys probably already have a plan for one of these, but if you don't here's a pic of a really simple adapter I used for another project. I worked great.