jeff2space
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No, your not missing anything. Thrust plate is not needed if MMT, CR, and TTW Fins are attached properly. I decided I wanted to use it on this project.
Ultimate Wildman - L3 Cert Build
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No, your not missing anything. Thrust plate is not needed if MMT, CR, and TTW Fins are attached properly. I decided I wanted to use it on this project.
jeff2space
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Drilled 1/4" holes along fin slots in booster to inject internal fillets.
Also did some sanding to fit centering ring and bulk plate into nosecone.
Bulk plate will be removable for possible GPS tracker.
Also did some sanding to fit centering ring and bulk plate into nosecone.
Bulk plate will be removable for possible GPS tracker.
AlnessW
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What will you be doing to secure said bulkplate?
jeff2space
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I'll be drilling three holes in centering ring for tee nuts. Centering ring will be epoxied into nosecone. Bulkplate will be screwed to centering ring through tee nuts. I'll show this when I get to that point.
AlnessW
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Sounds good - the trick is always seems to be making sure that nothing will pull loose.
JDcluster
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It more of a problem of them backing out.
You can use another CR to sandwich them into place.
I have moved onto threaded inserts.....
A couple drops of you favorite metal bonding epoxy then, you drive them in with a ratchet, nut driver, or cordless drill...
JD
You can use another CR to sandwich them into place.
I have moved onto threaded inserts.....
A couple drops of you favorite metal bonding epoxy then, you drive them in with a ratchet, nut driver, or cordless drill...
JD
AlnessW
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jeff2space
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Before glueing the CR into the nosecone I decided to test fit it into the payload tube and I'm glad I did. The coupler on these new nosecones (especially 6") are more flexible than the old fiberglass nosecone couplers. The CR needed more sanding as it was deforming the coupler section and the nosecone wasn't sliding into the payload section.
JDcluster
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What I do with the FG nosecones:
Cut a piece out of a coupler and slide it in to help strengthen and backup the CR you want to glue in place.
JD
Cut a piece out of a coupler and slide it in to help strengthen and backup the CR you want to glue in place.
JD
jeff2space
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Great idea, thanks!
jeff2space
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Hopefully will find time tomorrow to glue in motor mount. Will hold off on nosecone until I can get about 2 inches of 6" coupler from Wildman.
jeff2space
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Epoxied tee nuts onto CR for nosecone bulk plate.
jeff2space
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Epoxied MMT with CRs into Booster section.
Not the neatest job, but it works and who's going to see it (besides TRF).
Next will be installing fins.
Not the neatest job, but it works and who's going to see it (besides TRF).
Next will be installing fins.
jeff2space
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Sanded root sides of fins and exterior of booster along fin slots with 60 grit sandpaper. Exterior of MMT was completely sanded before it was installed.
jeff2space
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Ok, here's the method I came up with for installing straight fins on a 6" rocket.
Each fin slot is transferred 180 degrees and marked with a line. Two 8"x12" framing squares are clamped together to form a U. One long side of U is clamped to fin. Other long side of U gets lined up with line on opposite side. This should provide a straight fin.
Each fin slot is transferred 180 degrees and marked with a line. Two 8"x12" framing squares are clamped together to form a U. One long side of U is clamped to fin. Other long side of U gets lined up with line on opposite side. This should provide a straight fin.
Rrwjr
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Pretty clever idea Jeff. Should work out good as I haven't had fins slots that weren't 180 from one another on a 4 fin design from Wildman, but I have had slots that were cut at non 180 degree intervals on a different manufactures kit. Didn't realize it till I had fins tacked.
It looks like you have a three fin BT, so you have to be sure your 180 deg line is accurate, then you have to make sure that you compensate for the offset of the two squares being clamped to each other, and one of them being clamped to the side of the fin and not the centerline of the fin. It seems pretty complicated and needs a lot of calculations. It won't be simple, but should be doable. How accurate do you want to be?
I've found that a piece of 1/4" foam board, a protractor and compass to layout lines and a new blade in the exacto knife can produce a form to align fins pretty accurately. You might want to consider that.
Good luck.
jeff2space
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Yes, it's three fin. Drawing the line is the critical part but it just finding the center point between each fin slot.
One square is clamped to side of fin. Second square is clamped to first square on same side as fin which makes second square pretty close to being in same vertical plane as the fin. This square gets lined up with 180 degree mark.
I've thought of that but my "art" skills are horrible so I came up with this plan. Is it 100% accurate? No, but it looks pretty close.
Thanks.
Shouldn't this get lined up to a line 1/2 the fin thickness from the 180 deg. line?
Assuming the 180 deg. line marks the centerline of the fin, if the second square is in the same plane with the surface of the fin and not the centerline.
That's why I said I thought it was do-able, but complicated.
jeff2space
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I know this is rocket science but this method is close enough for me. There's some error in measurements, square thickness, line thickness, fin thickness, etc. In the end I double check everything using the best tool available, my eyes.
jeff2space
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Just a brief update, installed the third fin tonight. Everything looks good. Next step will be internal fillets.
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Jeff
Looks like your doing a great job. When are you planning to make its flight?
See you at the Bong
Looks like your doing a great job. When are you planning to make its flight?
See you at the Bong
I know this is rocket science but this method is close enough for me. There's some error in measurements, square thickness, line thickness, fin thickness, etc. In the end I double check everything using the best tool available, my eyes.
I hear that! Isn't it amazing how close and accurate you can get just eyeballing it! That's about all I ever use on the LPR & MPR. I tend to get a little more anal about the HPR. Probably don't need to, butt....
smarra01
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This is how I aligned the fins on my DarkStar extreme.
I started out by printing a template from https://www.payloadbay.com/index.php?page=Tools&action=FINGUIDES
I took a piece of 1/8 inch plywood and cut into 2 18" squares.
A 4 inch hole was drilled through the middle of both pieces and some 1"x3" poplar strips were glued and nailed to one of the pieces using the template as a guide.
The other piece was used at the end of the tube to hold it level, so that I could inject the fillets.
I started out by printing a template from https://www.payloadbay.com/index.php?page=Tools&action=FINGUIDES
I took a piece of 1/8 inch plywood and cut into 2 18" squares.
A 4 inch hole was drilled through the middle of both pieces and some 1"x3" poplar strips were glued and nailed to one of the pieces using the template as a guide.
The other piece was used at the end of the tube to hold it level, so that I could inject the fillets.
jeff2space
Well-Known Member
Thanks Gary! First I thought my L3 attempt would be June of 2016 (yes, I said 2016). But my build has been moving right along so now I'm thinking I would get a shake down flight in August and a L3 attempt in September. I have to place an order with you yet on the parachutes for this project but don't have the funds yet. You should see it in a couple months.
See you at Bong!
jeff2space
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Thanks for the link. I forgot about this site and actually have never used it. Think I'll print out a template and see how close I am.
jeff2space
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Started some work today on Electronic Bay. I will be using six switches. Three for primary altimeter and three for backup. One for Main charge, one for apogee charge and one for altimeter power.
jeff2space
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I do not want to turn this into a debate because this has already been discussed on other threads (see post #91). The NAR L3 High Power Cert Requirements states:
2.4 The capability must exist to externally disarm all pyrotechnic devices on-board the rocket. In this context, ‘disarm’ means the ability to physically break the connection between a pyrotechnic system and its power source. Simply turning off the device controlling the pyrotechnic(s) may not be sufficient.
I'm using one switch for device, one switch for apogee pyro, and one switch for main pyro. Does this add extra failure points? Yes. But pyro switches will be armed first and altimeter will tell me good continuity when its armed so I think I will be good. Again, I know all the arguments for and against but I decided to build my L3 cert rocket this way. I may or may not change it after a successful cert flight.
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