Latest file includes the C10 and B14 in the 18mm packages. Added the 13mm and 18mm packages for several of the other motors as well.

Attached Files

SEMROC.rse (94.2 KB, 12 views)

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Craig McGraw

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SAM 0044
AMA 352635

This is a revision of an older design, but one that really begs for one of the potential SEMROC motors. I tried out a C10-3, and wound up with the perfect match. The Dv is feather-soft at a mere 3 FPS, and the time delay of 3 seconds was just ahead of apogee. The model jumps off the pad and reaches flight velocity in less than 20".

Length: 40.196"
Diameter: 1.34" (ST-13)
Fin Span: 8.11"
Weight: 3.41 oz

C10-3......360'......Dv 3 FPS

I chose to use the 3/16" launch rod due to the length of the model.

Enjoy!

Attached Thumbnails

   

Attached Files

Star Ranger.rkt (62.4 KB, 4 views)

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Craig McGraw

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AMA 352635

Craig said,




Craig, I realize that these new tubes are preliminary but I just
started thinking like a carpenter again .
I was just playing with these ST-4 and ST-6 tube as motor mounts and
realize that they don't fit very well into other tubes(ST-5 and ST-7).
Maybe we should make them a little thicker to fit into other tubes as
sleeve motor mounts.

*Maybe ST-4 OD(.425) change to .51 to fit into a ST-5(.515)
*Maybe ST-6 OD(.626) change to .745 to fit into a ST-7(.715)
I am narrowing each about .005 which is what Carl's HTC couplers are narrowed.

My reason are to easily fit the new tubes into existing tubes. Also I
like the ST-5 tubes from the SchoolYard Sounder design and would like
to use the 10mm motors in them easily. Also there are no nose cones for either
new tube and an CR that is .09 tall is just too small (ST-4 to ST-5) .

What are your thoughts on this.

James Pierson
NAR# 77907

How about masking tape wrap and a layer of glue in place of a CR? That should take up any slack I would think. Although, having the tubes resized does make sense in the fact you could make couplers out of them also.

On the ST-4, you're describing a wall thickness of 0.0555", or just a fraction thicker than Carl's 0.05" fiberboard material used for centering rings. That's a very thick-walled tube, thicker even than Carl's LT series of tubes.

On the ST-6, using an OD of 0.710", the wall thickness becomes 0.058". Again, a very thick-wall tube.



I see your reasoning behind it, but I think you need to look at other possibilities for those centering rings instead of laser-cut fiberboard. Think about using 3/16" wide thick-wall spiral-wound tubes as centering rings. This is really all that the Estes rings, Apogee rings, and even some of Carl's rings, are. I would rather go this route than try to increase the wall thickness of the ST-4 or ST-6 series. Remember, fitting them inside ST-5 or ST-7 tubes is not their only application. These tubes could eventually have their own sets of turned components; you can "create" these components yourself in RockSim.

Give me some additional time, and I'll work up a full set of components around these tubes. The wall thicknesses of these tubes are "standard" in comparison to the other tubes; I'd really like to keep it that way if possible.

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Craig McGraw

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SAM 0044
AMA 352635

Best guess for ST-4 is:

ST-4 0.406" ID 0.432" OD .013" Wall

10mm tube will be mfg at .3940" OD (10.0mm) because that is FAI minimum.

After pressing, it can expand to about .400". That leaves about .006 clearance. If it expands more, we will reduce starting size to wind up with 10.0mm.

That makes the centering rings .032" wall thickness for ST-5 (with .002" clearance)

CR-4-5 0 .434" ID .498" OD probably from fishpaper like HTC-5.

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Carl McLawhorn
NAR#4717 L2
semroc.com

I was thinking along the lines of using the ST-4 tube for the 10mm motors, but you're describing yet another tube that's smaller than this. What exactly is going to be the OD for the 10mm motors? The casing OD would have to be smaller than 10mm to fit into a 10mm OD tube. I was under the impression that the motor casing itself was 10mm, but you're saying the FAI minimum is for the body tube itself, and thus the motor would be smaller.

A fishpaper centering ring would be nice and stiff, come to think about it...

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Craig McGraw

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SAM 0044
AMA 352635

Sorry. That was not too clear.

10mm ENGINE tube will be mfg at .3940" OD (10.0mm) because that is FAI minimum.

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Carl McLawhorn
NAR#4717 L2
semroc.com

So, are you saying you want a tube that is larger than my ST-4 spec of 0.399" ID and 0.425" OD for use with these 10mm motors? A little more slip-clearance inside? I was trying to match the slip-clearances given for the ST-5...

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Craig McGraw

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SAM 0044
AMA 352635

The attached files contain listings for the new Semroc ST-4 and ST-6 components, based on recent discussions. Please go through your current RockSim files (BHDATA, BTDATA, CRDATA, and TCDATA) and remove all references to earlier versions of these components before installing the new files. This is unfortunately a manual process using Excel (or Notepad); there is no automated way to remove old data from the database files yet. Leave all other Semroc component data as it is.

Save these four files in the ROCKSIM | DATA | NEW folder before running RockSim. The program will merge the data from these files into the master files of the same name for you.

I will try to develop NCDATA and TRDATA files (nose cones and transitions) shortly.

Attached Files

	BHDATA.csv (222 Bytes, 8 views)
	BTDATA.csv (1.3 KB, 5 views)
	CRDATA.CSV (1.8 KB, 6 views)
	TCDATA.CSV (246 Bytes, 6 views)

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Craig McGraw

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SAM 0044
AMA 352635