bracesport
Legendary member
The last pieces of the puzzle are in place!
Phantom V3 - DLG - Design Build
- Thread starter bracesport
- Start date
bracesport
Legendary member
These latest prints worked out well for the 22mm spinner and motor mount - I used Polycarbonate for the prop mount so it is very strong - hopefully these will be the final parts!
bracesport
Legendary member
I put in a 50gsm FG 'outer skin' layer to get a good surface contact with all the fiddly sections of the mould - I also added two layers of 40gsm UD - after curing I will do the proper layup with CF and join the moulds with a balloon - the nose section will be FG.
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bracesport
Legendary member
Getting close to laying in the CF.
I was planning to put a tube inside the balloon and stretch it out to 1m to lay into the fuse but I could not get the balloon to play ball!
I had an idea to just stretch the balloon by clamping one end at the tail and fitting the other end with the silicon tube (for inflating the ballon) doubling as the seal at the neck - I dry fitted the moulds and pumped up the balloon up and it all worked well - I also plan to wax the balloon to assist in release.
To make the layups I will pre laminate the CF and partially cure it before trimming out the forms and putting them into the moulds - I may vac bag them flat, but I will see how the laminating goes with the roller first.
View attachment
I was planning to put a tube inside the balloon and stretch it out to 1m to lay into the fuse but I could not get the balloon to play ball!
I had an idea to just stretch the balloon by clamping one end at the tail and fitting the other end with the silicon tube (for inflating the ballon) doubling as the seal at the neck - I dry fitted the moulds and pumped up the balloon up and it all worked well - I also plan to wax the balloon to assist in release.
To make the layups I will pre laminate the CF and partially cure it before trimming out the forms and putting them into the moulds - I may vac bag them flat, but I will see how the laminating goes with the roller first.
bracesport
Legendary member
Getting the tail feathers cut on my un-equal arm wire cutting station (cuts tapers with mechanical geometry) - so far so good!
bracesport
Legendary member
I cut the platforms and marked the curvature to sand the nose profiles - I have a wee angled sander at home which I forgot to bring today.
bracesport
Legendary member
I also made a jig for clamping the balloon in place while setting up the moulds - I am good to go for next week.
bracesport
Legendary member
The LE of the tail feathers are sanded - I used my adjustable angle sanding block to rough out the LE angles - next it was onto the mounting sleeves which were tacked in with 5min epoxy using the alignment jig then filled with thickened epoxy under some mylar to smooth them out - hopefully there will be minimal sanding afterwards.
bracesport
Legendary member
Fingers and toes crossed! 
bracesport
Legendary member
Tail mounting sleeves seem to be good - phew!
bracesport
Legendary member
It held pressure for 5 days in the mould - this morning it took about half an hour to get it out of the moulds - I would have to say it is a bloody success! I am stoked as I thought is would most likely be a huge failure - the undercut removable sections in the wing saddle and V tail faring all popped off without a hitch!
In the end the mould became sacrificial after I broke a couple of sections - I am not too unhappy about that as I would improve the design and re-print the moulds if I do another one! There was no wax on the moulds, just two coats of PVC.
I drilled the pilot holes for the V tail mounts using guide holes in the moulds before removing those sections - I need to cut open the canopy section to remove the balloon.
A very happy chappy!
View attachment
In the end the mould became sacrificial after I broke a couple of sections - I am not too unhappy about that as I would improve the design and re-print the moulds if I do another one! There was no wax on the moulds, just two coats of PVC.
I drilled the pilot holes for the V tail mounts using guide holes in the moulds before removing those sections - I need to cut open the canopy section to remove the balloon.
A very happy chappy!
bracesport
Legendary member
Yay the balloon came out easily after cutting out the canopy hole - my canopy cover needs a bit of work to fit properly but is all heading in the right direction - the tail mount sleeves are in and I took the opportunity to dry fit the feathers - next the tails need to go into the vac bag and I can tidy up the mounting sleeves.
To add the wing mount screws I will cut an access hole between the mounting screws and to get the alignment I will 3D print another jig - at some stage I also need to cut off the tip of the nose and dry fit the motor - in the back of my mind I have been concerned the motor mount might be a bit small.
This is also the slimmest fuse I have made so it will be fun to fit the servos - I will probably put the tail servos under the wing but we will see where things are at with the CG first.
To add the wing mount screws I will cut an access hole between the mounting screws and to get the alignment I will 3D print another jig - at some stage I also need to cut off the tip of the nose and dry fit the motor - in the back of my mind I have been concerned the motor mount might be a bit small.
This is also the slimmest fuse I have made so it will be fun to fit the servos - I will probably put the tail servos under the wing but we will see where things are at with the CG first.
bracesport
Legendary member
Apart from forgeting to try the fluoro colours option the tails are in the bag - now we wait..
bracesport
Legendary member
I pulled the tails out of the bag and they are good! My rookie mistake was the mylars have a Gloss side and a Satin side so I ended up with Satin tops and Gloss bottoms - I really like the Satin so I will 1200 grit sand the bottoms to match.
Otherwise they are great - the Kevlar hinge looks to have worked well - I did not press in any relief to seat the Kevlar in the foam so there is a slight raised impression - next time I will go the extra mile there.
I think I will cut in the hinge then add a lick of epoxy to the raw foam edges.
V happy.
Otherwise they are great - the Kevlar hinge looks to have worked well - I did not press in any relief to seat the Kevlar in the foam so there is a slight raised impression - next time I will go the extra mile there.
I think I will cut in the hinge then add a lick of epoxy to the raw foam edges.
V happy.
bracesport
Legendary member
Nice - dry fitting the motor looks to be on the right path - I will need to do a bit more work to fit the tails and the wing to determine the hardware locations and CG, but I am quietly liking the progress so far - using CAD and moulds and 3D printing is awesome for dimensional accuracy.
Inq
Elite member
With you having refinements at the ultimate end of the spectrum using carbon-fiber/epoxy cured in female molds and gorgeous streamlining, I find it odd that you would leave the horns outside in the slipstream. Is there some technical/logistics reason you don't use short torque tubes on the aileron hinge line and have the horns on the inside... just a few millimeters inward?
bracesport
Legendary member
Inq
Elite member
Just now finding your thread and being newer than when it started, I'm going back through it. Apologies if I ask a question that you answered later. If I don't ask it when I find it, I'll forget.
Really top notch aerospace industry techniques you're using!
I see you mentioning shear webs, caps and assuming you're optimizing lay-ups for those. Since you find 170 grams heavy and seeing this post, I wonder... are you doing structural analysis? Closed-form, Mechanics of Materials or numerical, FEA? If so, what kind of margins are shooting for? Do you have any specifications on your CF?
Cool stuff!
Really top notch aerospace industry techniques you're using!
I see you mentioning shear webs, caps and assuming you're optimizing lay-ups for those. Since you find 170 grams heavy and seeing this post, I wonder... are you doing structural analysis? Closed-form, Mechanics of Materials or numerical, FEA? If so, what kind of margins are shooting for? Do you have any specifications on your CF?
Cool stuff!
Inq
Elite member
I've been thinking of designs using pull strings. What do you do to account for the changes in length as a function of stretch or even CTE? I've seen some of the both positive and negative CTE on some of the strings... nylon, monofilament, PE braided line, Dyneema, polyester, etc. Do you re-tie every flight day or have something that will give, like springs?
bracesport
Legendary member
I am aiming for an AUW around 270g (240g would be nice) - no analysis - just doing everything by feel!
Just now finding your thread and being newer than when it started, I'm going back through it. Apologies if I ask a question that you answered later. If I don't ask it when I find it, I'll forget.
Really top notch aerospace industry techniques you're using!
I see you mentioning shear webs, caps and assuming you're optimizing lay-ups for those. Since you find 170 grams heavy and seeing this post, I wonder... are you doing structural analysis? Closed-form, Mechanics of Materials or numerical, FEA? If so, what kind of margins are shooting for? Do you have any specifications on your CF?
Cool stuff!
