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-   -   Rockets for C6-5 on small fields (http://www.oldrocketforum.com/showthread.php?t=7066)

GlueyFingers 05-16-2010 02:25 PM

Rockets for C6-5 on small fields
 
C6-5s are the engines with the widest retail availability, but also have a reputation for putting small rockets "into orbit" which doesn't work well on small fields.

Wondering what kinds of designs strategies could lead to safe and recoverable C6-5 flights in smaller fields.

- Extra weight in the nose cone? Getting close to max lift weight would seem to limit altitude. What determines maximum lift weight anyway - acceleration to fin effective speed by the time it leaves the launch rod? Would a longer launch rod help?

- Draggy designs? Since drag is related to airspeed, this would seem to still permit reasonable acceleration to fin-effective speed on the launch rod, but limit maximum speed an altitude thereafter.

- Undersized recovery systems are an obvious one... better to have to re-glue a broken fin or two than replace a model that drifts into a tall tree.

sandman 05-16-2010 03:53 PM

Quote:
Originally Posted by GlueyFingers
C6-5s are the engines with the widest retail availability, but also have a reputation for putting small rockets "into orbit" which doesn't work well on small fields.

Wondering what kinds of designs strategies could lead to safe and recoverable C6-5 flights in smaller fields.

- Extra weight in the nose cone? Getting close to max lift weight would seem to limit altitude. What determines maximum lift weight anyway - acceleration to fin effective speed by the time it leaves the launch rod? Would a longer launch rod help?

- Draggy designs? Since drag is related to airspeed, this would seem to still permit reasonable acceleration to fin-effective speed on the launch rod, but limit maximum speed an altitude thereafter.

- Undersized recovery systems are an obvious one... better to have to re-glue a broken fin or two than replace a model that drifts into a tall tree.


Two words, Big Bertha! ;)

mycrofte 05-16-2010 04:52 PM

I've launched a Nike-X and Honest John in a 5 acre field with good results. Only bad recovery was the upper winds were stronger than on the ground one time.

CPMcGraw 05-16-2010 05:06 PM

Quote:
Originally Posted by GlueyFingers
C6-5s are the engines with the widest retail availability...Wondering what kinds of designs strategies could lead to safe and recoverable C6-5 flights in smaller fields...


Quote:
Originally Posted by sandman
...Big Bertha!...


I'll second his recommendation, and add a few others:
  • Estes Citation Patriot
  • Estes Der Big Red Max
  • Estes Blue Bird Zero
  • Semroc Goliath
  • Semroc Vega
  • Semroc Hydra-One

Larger-body designs tend to work well, and when combined with either several 2" x 20" streamers, or a standard 12" parachute, should recover well inside a moderately-sized schoolyard.

STRMan 05-16-2010 08:53 PM

Flying saucers.

hcmbanjo 05-16-2010 09:22 PM

I agree with the earlier posts. BT-60 sized rockets around two feet tall are perfect for smaller fields.

Many of the models I've produced were designed with small fields in mind. I hate to lose rockets.
Check out the Break-Away model.
http://www.oddlrockets.com/KitsPage2.html
Scroll down to the lower left.

It launches vertically, and breaks apart into six tethered pieces at ejection. It'll get more altitude than a Bertha style rocket, and your spectators will get a surprise recovery.
It falls horizontally with very little drift.

o1d_dude 05-16-2010 10:50 PM

Sandman got it in one.

The Big Bertha is the ticket and widely available. Der Big Red Max is no longer available but if you really want one you can buy a regular Red Max for the nosecone/fins/decal sheet and a Big Bertha for everything else. Or if you have sufficient spare parts you can clone one and get your decals from Sandman. The Blue Max set should work just fine.

I'm thinking about building another Big Red Max and this time going with a 24mm motor mount but that's another story.

GlueyFingers 05-16-2010 10:53 PM

Thanks for the ideas... one characteristic of my BAR-dom is a decision not to buy any kits, so it's more look at this plan and look at that plan and grab appealing features.

GregGleason 05-17-2010 06:16 AM

What about a B6-4?

Greg

STRMan 05-17-2010 07:15 AM

He stated it's easier to get C6-5's in his area in the original post.


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