COMPOSITE ROCKETRY ROCKSIM FILES

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PSLimo

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Hey Guys,

I'm looking for the rocksim files for a Composite Rocketry Lotus 5 & 8. They have a link on their website but I can't download the file.

Any ideas?
 

PSLimo

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Thanks Justin,

That was fast!
 

crossfire

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Justin
My pad will down load it but I can't open it. I don't have rock sim is that why?
 

crossfire

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Without Rocksim or OpenRocket you wont be able open the files.
Jf I attempted to down load open rocket and my pad said this file or down load may harm your device. What's up with that?
 

QFactor

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Jf I attempted to down load open rocket and my pad said this file or down load may harm your device. What's up with that?
A lot of people get that message. It's OK to download.

If you have problems getting it to run - usually it's a Java issue. Plenty of helpful threads on TRF to help with that.
 

PSLimo

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Hi Q Factor,

How did yours fly as it looks like it needs a lot of weight in the nose from the file you attached.

I was thinking of cropping the fins to give it a Loc Big Nuke look.
nukelook.JPG

lotus5.JPG
 

crossfire

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On my 5" with chute and shock cords in cone it balances out pretty close.
 

QFactor

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Hi Q Factor,

How did yours fly as it looks like it needs a lot of weight in the nose from the file you attached.

I was thinking of cropping the fins to give it a Loc Big Nuke look.
If you're doing head-end deployment, and you don't alter any of the components - you won't need to add any weight to the nose. That cone is way heavy. Attached is my final RockSim file. It accounts for all the masses for all the components; sled, batteries, u-bolts, electronics, harnesses, etc. But I did a final weighing, without the motor, and located the CG - and used that in the sim. It came in at 1.08 stability with a K695 motor. The rocket flew straight as an arrow.

Attached is a drawing of how I built the rocket. Since motor case length is limited, and the rocket is heavy, I laid out everything to figure out how to get a AT 1280 case in it. Some people are moving the bottom bulkhead forward to get more room.

When you run the sim - do not use the Barrowman equations. Use the rocksim stability equations.

Looking at your Rocksim pictures - why is you Avbay way up in the nose cone?
 

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PSLimo

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why is you Avbay way up in the nose cone?

That's where it's at in the rocksim file I was given and I'm definitely not an expert in rocksim.

Thank's for all the informative comments. I'm looking forward to having a sport flyer that's dual deploy in a shorter package and head end deployment seems to be the ticket in accomplishing this. Much simpler than the chute cannon's I've used in the past for stout rockets.

I also ordered the Lotus 8 for the same reason, a shorter rocket that will stay reasonably low and loud on a small "M". I fly at a challenging launch site in Bong Wisconsin where landing as close to the pad is paramount.

Thanks again for the replies,

Phil
 

QFactor

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why is you Avbay way up in the nose cone?

That's where it's at in the rocksim file I was given and I'm definitely not an expert in rocksim.

Thank's for all the informative comments. I'm looking forward to having a sport flyer that's dual deploy in a shorter package and head end deployment seems to be the ticket in accomplishing this. Much simpler than the chute cannon's I've used in the past for stout rockets.

I also ordered the Lotus 8 for the same reason, a shorter rocket that will stay reasonably low and loud on a small "M". I fly at a challenging launch site in Bong Wisconsin where landing as close to the pad is paramount.

Thanks again for the replies,

Phil
Here's the profile I get in Rocksim. You running Ver. 10? I'm running Ver. 9.

LOTUS-5-Rev13-FixedCG-TopFlightChute.jpg
 

PSLimo

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Neither, I'm using open Rocket. Looks much better and now I see the problem you're pointing out with a long motor case.

Since you're light years ahead of me with rocksim, do you think cropping the fins would have any stability issues?
 

QFactor

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Neither, I'm using open Rocket. Looks much better and now I see the problem you're pointing out with a long motor case.

Since you're light years ahead of me with rocksim, do you think cropping the fins would have any stability issues?
Here's my rocket with the fins clipped like in your drawings. Stability is at 0.95 with a K695 motor. I would say my build is safe to fly with the clipped fins. But I would have everyone on alert to be safe on the first launch. My rocket also has a good bit more weight in the fin area due to the way I did the internal fillets. So watch the weight and you should be fine.


LOTUS-5-Clipped-Fins.jpg
 

PSLimo

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Thanks,

I really like the look of the sleeker fin's.

I've built lots of stout rockets and I'm used to hearing at a launch "its Phil from Chicago with a scratch build and this is a heads up flight', lol!
 

QFactor

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Thanks,

I really like the look of the sleeker fin's.

I've built lots of stout rockets and I'm used to hearing at a launch "its Phil from Chicago with a scratch build and this is a heads up flight', lol!
Good luck with the build. Watch your clearance on the top bulkhead for fitting into the nose cone. I held mine back a little from where the nose cone's shoulder transitions to the tapered section. I experimented with the fits before epoxying the switch band. That bulkhead can get wedged solid at the transition point.

The picture shows the weep hole I had to put in the nose cone to let air out when sliding it onto the Avbay coupler. The cone and coupler were such a perfect fit that the air could not escape and the cone would not seat that last 1/4 to 1/2 inch.


IMG_4394[1].JPG
 
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crossfire

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Thanks,

I really like the look of the sleeker fin's.

I've built lots of stout rockets and I'm used to hearing at a launch "its Phil from Chicago with a scratch build and this is a heads up flight', lol!
But you know what Phil almost all of them flew great.
 

crossfire

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Here's my rocket with the fins clipped like in your drawings. Stability is at 0.95 with a K695 motor. I would say my build is safe to fly with the clipped fins. But I would have everyone on alert to be safe on the first launch. My rocket also has a good bit more weight in the fin area due to the way I did the internal fillets. So watch the weight and you should be fine.


View attachment 458999
It looks ok but it's no longer a Lotus. Looks like the same old thing.
 

PSLimo

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QFactor,

Great suggestion on the weeping hole. It does look a lot more aggressive with those fins.

Crossfire,

Do I know you from Bong? I think my craziest heads up fight was my Fat Man and it flew straight as an arrow.

_DSC0174.jpg
 

crossfire

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QFactor,

Great suggestion on the weeping hole. It does look a lot more aggressive with those fins.

Crossfire,

Do I know you from Bong? I think my craziest heads up fight was my Fat Man and it flew straight as an arrow.

View attachment 459021
You might know me I used to own Top Flight Recovery. We talked a bit last summer when you made your rocketry come back.
 
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PSLimo

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I remember,

Look forward to seeing you at next month's launch.
 

QFactor

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QFactor,

Great suggestion on the weeping hole. It does look a lot more aggressive with those fins.

Crossfire,

Do I know you from Bong? I think my craziest heads up fight was my Fat Man and it flew straight as an arrow.
Here are some pictures from my build . . . .

IMG_8952.JPG I drilled three holes in the bottom centering ring so that I could inject epoxy for the internal fillets.

IMG_8884.JPG Added a small piece of plywood for the rail button. Everything is epoxied - except for the the screw.

Lotus-1515-Buttons-01.JPG I started out with 1010 buttons - but went with 1515. The 1010 looked too wimpy - and on the edge for a nearly 15 lb. rocket.

IMG_4146.JPG Initially there was just the Stratologger, but then I added a Quark for redundancy. Both worked perfect.

IMG_4145.JPG This is the bulkhead that faces the motor casing.

Lotus-5-Chute-01.JPG Here's the 70" chute that Top Flight made for me. Worked perfect. And fit nicely in the cone with the harness and chute protector.
 

PSLimo

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You're doing something with your u-bolts that I never thought of and eliminates the need for an extra quicklink. Such a simple solution to just put it through the u-bolt before bolting it to the bulkhead.

Learn something new everyday.
 

QFactor

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You're doing something with your u-bolts that I never thought of and eliminates the need for an extra quicklink. Such a simple solution to just put it through the u-bolt before bolting it to the bulkhead.

Learn something new everyday.
Here's something to think about on the harness between the Avbay and the motor.

IMG_4415.JPG The picture shows the u-bolt at the motor tube. On a long motor case I didn't want a Quick Link thrashing around and banging up the motor case. I threaded the harness thru the end loop (eye) so it's in a "choker" arrangement. But when I ordered the harness I asked for a "twisted eye" on that loop so that it would sit flat as a choker.

IMG_4410.JPG In this picture the Left loop (eye) is a "Twisted Eye". The Right loop is a standard loop.
 

GaryT

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I designed the LOTUS Series for Composite Warehouse, Here are the real Rocksim files. Just change the weight and the CG to what your kit comes out to. Also I use a ratio between Rocksim and the Barroman method to determine my CP. Here is what I recommend for the CP for each size LOTUS.

3" CP - 25.65 from the NC Tip
5" CP - 39.94 from the NC Tip
8" CP - 62.40 from the NC Tip
 

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PSLimo

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Hi Gary,

Thanks for the files.

Thought I'd let you know why I'm changing the fins of the Lotus as it has nothing to do with your design. I did my Level 3 with a Mega Nuke and love the look of that rocket. I wanted a stout version and removing the 30" coupler would achieve this and thought I could use all the wasted space on the nose for dual deploy.

Fast forward 10 years and head end dual deploy is now a thing.

Here's what the Mega Nuke without the 30" coupler would have looked like:

mnuke.JPG

Cropping the Lotus fins in Q Factors mock up looks even sleeker.
LOTUS-5-Clipped-Fins.jpg
 
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