I save all my drawings like that. Might be cool to frame a collection of them at some point. It's art! Abstract impressionism?It's a rough sketch and very much not to scale. Still flying the G12.
I save all my drawings like that. Might be cool to frame a collection of them at some point. It's art! Abstract impressionism?It's a rough sketch and very much not to scale. Still flying the G12.
The mylar sleeve makes it easy to slide the motor casing out after curing, as long as you make it longer than your layup so that the epoxy can't sneak in underneath. Today since I was using flash tape for release on the tailcone closure, I had the mylar end at that joint, and I put a bunch of grease in there to keep the epoxy out. That didn't work for me today, and I had to cut off the carbon tapered end and a bit of the tube, to be able to break the motor case loose. The motor case probably isn't usable any more, unfortunately.Interesting using a motor casing as a mandrel. I would be afraid of not getting the carbon fiber off my motor casing.
1.17"What's the OD of your tube?
Yes, it's the Apogee nosecone. It's not a perfect fit, but close enough.Adrian --
Is that the Apogee 29mm PNC 29MM Nosecone in your photo ?
Apogee: PNC 29MM
According to Apogee ( and they're usually very accurate with weights and measures ), the diameter is 1.176 inch and your carbon tube is 1.17 inch.
Does the nose match your airframe tube as well as it sounds like it would ?
Thanks !
-- kjh
Any chance you can link the forum you read. I've been toying with the idea of printing a tailcone for my Min 38mm that I'm building and if I make a tailcone it gives me a few thousand more feet of altitude.I did a little forum research and found someone who did some testing, and found that the threshold the problem for a cylindrical back end was when the motor was recessed 1.0 body diameters from the end. The back of the nozzle with this tailcone is recessed 0.877" from the tailcone exit, and the tailcone exit ID is 0.95." Maybe it's o.k. as is?
@Adrian A --I did a little forum research and found someone who did some testing, and found that the threshold the problem for a cylindrical back end was when the motor was recessed 1.0 body diameters from the end. The back of the nozzle with this tailcone is recessed 0.877" from the tailcone exit, and the tailcone exit ID is 0.95." Maybe it's o.k. as is?
@kjhambrick found the same material that I did.Any chance you can link the forum you read. I've been toying with the idea of printing a tailcone for my Min 38mm that I'm building and if I make a tailcone it gives me a few thousand more feet of altitude.
Why not ask the prefect in advance, just for your peace of mind and to simplify your planning? Some clubs are cool with Class 1s doing Class 1 things, but others won't countenance the waiver being exceeded, no matter by what.When I do my sims in RASAero now, the altitudes are high enough that I think I'll start next weekend with an F10 to go for the F record, and then if the altitude is in line with the RASAero predictions, see how the prefect feels about exceeding the FAA waiver with a rocket that doesn't need a waiver.
Just different styles I guess. I’d rather reduce other uncertainty first, like will I get my rocket back intact after an F attempt. I’m also leaning against going for the G record under circumstances that are questionable, anyway. If the rocket underperforms the sim on the F flight and I’m confident it would stay under 14200 on the G, I’ll probably go for it. The Tripoli launch site is the highest in the country, but every site has its challenges and limitations, so it feels more fair to set for the record at NCR or NSL in Alamosa next year if it wouldn’t stay under the Hartsel waiver.Why not ask the prefect in advance, just for your peace of mind and to simplify your planning? Some clubs are cool with Class 1s doing Class 1 things, but others won't countenance the waiver being exceeded, no matter by what.
Curious when/where do you plan on flying? Isn't NCR doing 1 more launch at their north site or are you trying to launch sooner?
What a kool idea, @SolarYellow !I’d look at fabbing a 5-degree taper and end it at a 90-degree cone outward from the perimeter of the nozzle boss. Just as a guess that feels right. You could always build a test stand and burn some motors.
FAR?The Tripoli launch site is the highest in the countryso it feels more fair to set for the record at NCR or NSL in Alamosa next year if it wouldn’t stay under the Hartsel waiver.
https://d11fdyfhxcs9cr.cloudfront.net/templates/170652/myimages/g12st-p_dms_assembly.pdfWhat a kool idea, @SolarYellow !
This is an AT 29mm nozzle with a 0.180 inch throat and a 30-degree exit cone from The RCS Site: 29/38mm Nozzle, 0.180" Throat.
View attachment 608628
I don't know if this is the same nozzle as the G12 but it might be fun to make a composite attachment for the nozzle-end that extends the exit cone out to the circumference of an ogive boattail that matches the airframe.
Note that the nozzle is only 1.000 inch in diameter where the OD of the 29mm motor casing / ID of the airframe are about 1.14 inches so the ogive boattail would be wider and longer than suggested by the nozzle dimensions.
EDIT: about like the tailcone in Adrian's photos above ...
Eyeballing the RCS blueprint, it looks like the ogive boattail L/D ratio could be long enough to actually reduce base drag more than a little bit !
So, I wonder if @AeroTech has published the actual specs of a G12 nozzle ?
What fun !
-- kjh
EDIT: After studying the blueprint a little longer, I see I should have included the table of part numbers -vs- throat diameters:
View attachment 608629
Adrian --Just different styles I guess. I’d rather reduce other uncertainty first, like will I get my rocket back intact after an F attempt. I’m also leaning against going for the G record under circumstances that are questionable, anyway. If the rocket underperforms the sim on the F flight and I’m confident it would stay under 14200 on the G, I’ll probably go for it. The Tripoli launch site is the highest in the country, but every site has its challenges and limitations, so it feels more fair to set for the record at NCR or NSL in Alamosa next year if it wouldn’t stay under the Hartsel waiver.
I’d look at fabbing a 5-degree taper and end it at a 90-degree cone outward from the perimeter of the nozzle boss. Just as a guess that feels right. You could always build a test stand and burn some motors.
I'm talking about the pad altitude. About 8800' for the Tripoli CO Hartsel site.FAR?
What a kool idea, @SolarYellow !
I don't know if this is the same nozzle as the G12 but it might be fun to make a composite attachment for the nozzle-end that extends the exit cone out to the circumference of an ogive boattail that matches the airframe.
The F10 sims to right around 8900 with a boat tail. If I fly it and it goes straight but to 7000 feet, then the sim says I would only expect 12,750 feet on the G and I would fly it with confidence. But if the F10 goes to 9000 feet, then I would expect over 15k on the G if I use the same boat tail. In that case I probably would fly it without the boat tail or not at all.Adrian --
My rough sim puts a similar 65 gram rocket at Hartsel at over 8k feet ...
What do you mean by 'underperforms on the F flignt' ?
Thanks for pointing out Kelly Bruland's TRA F Record, Adrian.<<snip>>
The F current record is 7989 feet, launched from about 4500 feet ASL in Oregon. I've seen Kelley's beautiful work on the rocket, especially the nosecone, and it paid off with an impressive flight. If I were to fly this rocket from 4500 feet RASAero says it would only get to about 7600 feet. I'm glad that the new Tripoli record search implementation shows the data from the previous records also, so that Kelley can continue to get credit if I beat his record partly due to a higher launch site.
FAR?
I thought he was talking ffa waver.I can’t speak for FAR but the adjacent MTA is at 2040 feet ASL.
Bill
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