ACP Composites
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markkoelsch
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I thought they were just a materials supplier.
Yea but I saw this here https://www.acpsales.com/1-mm-High-Gloss-Twill-Carbon-Fiber-Sheet.html. Im not to sure if they do it for non-vendors though.
dixontj93060
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I have been ordering from them for 5+ years. Yes, give them a call, I believe they do custom work, but my impression it is for higher volume production.
markkoelsch
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I am sure you can buy it. Whether they will cut part for you I cannot answer. I assume this is for the 1mm thick fins you want? If I understand you correctly you want these fully air foiled, correct? That will take much machining per fin. You might want to start with slightly thicker material.
I believe Chris Attebery does make air foiled fins, but only one style. $140 for three. Not sure if he would tackle this or not. He is on TRF, but I cannot recall screen name.
The other option already mentioned was Charlie Ogino ( spelling).
At this thickness do they really need a full airfoil? A good leading and trailing edge bevel would likely get you close with a lot less fuss and cost.
I believe Chris Attebery does make air foiled fins, but only one style. $140 for three. Not sure if he would tackle this or not. He is on TRF, but I cannot recall screen name.
The other option already mentioned was Charlie Ogino ( spelling).
At this thickness do they really need a full airfoil? A good leading and trailing edge bevel would likely get you close with a lot less fuss and cost.
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I looked into having Space Cowboy fins downscaled to 24mm. At this scale there's not really enough material to fully profile.
markkoelsch
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I would check out Dragon Plate- I know they have 2mm. Maybe with a router table you could put an adequate bevel to meet your needs as I think what you are asking for, while likely possible if you want to spend a lot of cash, is not practical.
I don't know if they do custom work but I purchased some high temp vac bag fittings and vac bag consumables off them April/May 2016 and they were responsive and had knowledgeable people at the other end of the phone. Also shipping to Canada was fine and they had reasonable rates once I spoke with them, I used USPS.
What custom work are you looking at, tubes? If so talk to Charles Ogino from Carolina Composite Rocketry.
What custom work are you looking at, tubes? If so talk to Charles Ogino from Carolina Composite Rocketry.
dixontj93060
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I doubt if they will do cutting; not really their business. I thought you were asking for a special layup--either a sheet or a tube.
No, their sheets are avalible on their website (https://www.acpsales.com/OnlineStore.php?cat=5377). In the discription they offer "CNC Machining, Cutting, Countersinking, Bonding, Silk-Screening, Painting, and Clear Coating" so i would assume that would include cutting fins..
dixontj93060
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Oh, well maybe. I have bought their standard carbon plate two or three times, but I think they can do specials such as high-temp, combo Kevlar layering, etc.
Oh. Could they also do boatails?
dixontj93060
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I think you'd be better off buying from Wildman. It would cost a bundle for ACP to design and produce a mandrel. So unless they were doing a large volume they couldn't amortize the up front costs. Mr. Lehr does that for you through his volume.
Ok thanks.
A one-off custom boattail might be pretty expensive. A few years ago I made a run of 1.5"-24mm fiberglass boattails. The making of a plug, then mold, then getting the layup right is very time consuming. You'd be looking at a $250 boattail regardless of size due to labor alone.
What about making a 3D printed mold? That would be alot cheaper.
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That takes care of the plug & mold, maybe. But there's a lot of labor there in finishing the mold, creating the part, and finishing the part.
Of course you can jump straight to a 3d printed boattail or NC, or turn one out of basswood, or whatever.
Wherever you do it yourself, plan for extra materials dollars. Wherever you have it done, plan for extra labor dollars.
Of course you can jump straight to a 3d printed boattail or NC, or turn one out of basswood, or whatever.
Wherever you do it yourself, plan for extra materials dollars. Wherever you have it done, plan for extra labor dollars.
Perhaps. Not sure about successfully polishing a 3D printed part to a mirror finish, though. Otherwise the part won't release. I'm sure it's been done, though.
The boatail is going to be pretty close to the nozzle and so I want it made out of a lightweight, strong material. CF is too expensive but Fiberglass is fine.
Exactly. But it still needs to be polished or the part won't release from the mold. What diameter airframe is the boat tail for?
A fiberglass BT-50 (24.8 mm).
I'm confused then. Isn't this for a 24mm motor? What diameter would the boattail reduce to?
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Topload a disposable 24mm APCP that has the nozzle protruding aft? I have that in mind for my 18mm D's.
The boatail's aft diameter is around 19 mm, length is 17mm, and fwd diameter is 24.8 mm. It is connected to a 24.8 mm diameter body tube.
Sounds like it would extend past the nozzle quite a bit, reducing your thrust a bunch. Not to mention the thrust ring from the aft closure that would prevent you from attaching ithe boattail to the airframe. The diameter of that thrust ring is ~28mm.
Carolina Composites makes a tapered aft closure for the CTI 24mm hardware that might be exactly what you're looking for. Not sure if that part would be legal for a CAR record attempt, though.
I am confused. Why would it reduce the thrust? It's not like the boatail is going to be in contact with the flame.
I am using a custom closure that is attached with the boatail and so the nozzle will not exactly be flush with the top of the boatail. Rather, it will be a couple mm ahead so that the flame will not come near to the boatail. And I think the closure itself will be legal, since I am not exactly modifying it in any way.
What about making the boatail and then dissolving the mold?
If the nozzle is up inside the boattail it will reduce thrust because of something called Krushnic Effect. Even if it's not in contact with the flame.
And the closure is "custom" but not modified? Anything other than the exact part from CTI would not be legal for a record. And that part can't be modified in any way, otherwise it's an EX motor, and not legal for records.
Many people make male molds from styrofoam and dissolve it with gasoline.
