Posts: 112
Joined: 1/21/2006 From: Lake Wales,
FL, USA Status: online
I have a question. I am about to start laying up some fuselages for 428 and would like to know what you guys use.
I have seen some use all fiberglass, fiberglass & carbon as well as fiberglass & wood. What seems to work the best, and what weights of glass and wood do you use?
I also see some of you bond the seams during fabrication. Is there a reason you don't vacuum bag it (like a wing) and then join the halves?
Thanks for the help!
< Message edited by Scorpion Racing -- 5/28/2008 12:21:22 PM >
Posts: 1245
Joined: 1/20/2004 From: Emerald,
WI, USA Status: offline
Well Scott, welcome to what could be the most frustrating thing you've ever done.
So far I've found that a layer of 3oz, 6oz then 3oz again yields a very stiff fuse and the weight seems ok.. I've tried with less cloth but I don't think it's stiff enough.. I was told by Terrance (manufacturer of the Neme Q+) to shoot for around 7 - 8oz with the firewall, hold blocks and paint..
As far as joining the halve goes, I'll let someone else answer because I haven't been able to get a single one to turn out a good seam yet.. I always end up with some voids.
Posts: 112
Joined: 1/21/2006 From: Lake Wales,
FL, USA Status: online
Thanks Lee, talking about fun? I spent 15 hours making a parting board for the fuse alone! Anyone who thanks this is the easy way out is sadly mistaken!!
Do you think the fuse could benefit from vacuum bagging and either carbon or balsa added?
Posts: 2795
Joined: 12/29/2001 From: Brantford, ON, CANADA Status: offline
Maybe it is too late but I would recommend a "Bathtub" type mold. The sides, top and bottom of the finished part have no seams. The seam is along the bottom corner of the fuselage, it is much easier to produce and correct any voids. I use one layer of 2oz and one layer of 6oz with a layer of 1oz carbon from the firewall back to the landing gear plate. I take a couple of strings out of that heavy "Waffle" weave cloth and add to the top corner to act as longerons, that and the joint overlap at the bottom provide all the stiffness required. I mold and join everything at one time while the whole layup is wet, this includes the firewall, landing gear plate and wing mounting blocks. Weight when it comes out of the mold is 6oz.
Posts: 112
Joined: 1/21/2006 From: Lake Wales,
FL, USA Status: online
Thanks Ed,
It isn't too late,... because your method is the one I used! Your method seemed logical to me and allowed easy access to the seams, so I copied it. My fuselage makes a drop to the gear, then a reverse curve up and a sweep after the v-tail. Did I mention the sides and top are also Coke bottle shaped? Not the easiest shape to create a parting board for to say the least! I have the fuselage mounted on 3/4" wood, with 3/4" supports under 7 stations at points down the bottom to create the curves as well as in front of the firewall, and then mounted the parting board to this structure. I need to add some registration bumps and then lay up the mold on this. If all works out as planned, I should end up with a mold that looks quite close to yours.
Ed, where do you get 1oz. carbon cloth? 6oz. finished weight sounds great!
Does anyone think vacuum bagging the fuselage would give a stronger/stiffer product?
Thanks for the replys, keep them coming if you have any ideas...
Posts: 1245
Joined: 1/20/2004 From: Emerald,
WI, USA Status: offline
The problem I've had trying to bag the fuse sides is getting down in the fuse mold all the way.. It gets difficult to make sure the bag isn't hanging up on the flanges of the mold or whatever.. Ed's way would be fairly easy to do the bottom but the top would have issues I would think.. However, the nice thing about a mold, as long as nothing sticks you aren't out much if something doesn't work..
I'm going to be tackling the second version of my quickie shortly.. Starting from scratch again.. I to copied parts of Ed's technique.. I may part mine the same way this time..
Posts: 248
Joined: 8/14/2002 From: Shakopee,
MN, USA Status: offline
Hi Scott This is just my opinion on RC Q-500 fiberglass fuselages. I have build over 100 the last 8 years and change something each year to make them better. I race mine and see the points that need to be reinforced. If you a using fiberglass and carbon fiber you do not need to vacuum bag. If you use balsa and fiberglass, I think you need to vacuum for a good bond. Here is how I do it. 1. Wax mold twice with dolphin wax. 2. Paint with PPG concept DCC. 3. One pump of epoxy, mix with capbosil to the consistence of ketchup. 4. Brush this on the inside of fuse mold with extra laid in the corners and curves. 5. Lay in style 120, 3.16oz crowfoot weave fiberglass, wet out with epoxy. 6. Lay in a half piece of 3.16oz from firewall to trailing edge of wing saddle, wet out. Add a couple of fiberglass pieces around tail. 7. Lay in Carbon Fiber 5.7oz strip 2” to 1” from fire wall to tail, on each side. Add a couple 1”by 3” for landing gear. Wet out. 8. Final layer is 6oz soft weave fiberglass. Wet out. I also use this for the lap joint. The firewall and landing gear blocks are ¼” plywood. Weight is 6 1/2oz. I have used West and EZ lam epoxy, did not like either one. MGS is great but hard to get and expensive, I am now using Adtec Pro Built from Cass, works good. Good Luck, and hope to make your race again next March.
Posts: 112
Joined: 1/21/2006 From: Lake Wales,
FL, USA Status: online
Thanks Randy,
I was glad to get to talk to you again at the spring race and hope you can make it again. I hope you will be racing against a Scorpion in 428 next March!
I will be using MGS resins for the molds as well as the parts, but I will pull a few parts before I try to tackle painting in the molds. My plan is to lay up the molds next wekend, and start pulling my first parts within a month. I will try a few different lay ups, and modify as I see what is needed for my design. That's how I had to do it with the woodies in 424, so I am used to the trial and error process! [)]
It's great to have guys like you who are willing to pass along what you have learned to help others out. I really appriciate your help. Any more help you guys have would be great!
Posts: 153
Joined: 11/29/2003 From: Erie,
MI, USA Status: offline
Here is what I do. To make the fuse. 1 Layer or 2 oz glass. A pice of 2 oz Kevlar in the LG area, 4.3 uni, carbon from the FW to 1/2 of wing, Then a last layer of 6.0 glass, and a wet lap seam. With a weight of 7.0 to 7.5 oz. With a molded in V stab saddle and FW, and other wood
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Posts: 112
Joined: 1/21/2006 From: Lake Wales,
FL, USA Status: online
Thanks guys. I think the general formula I am coming up with is:
1.) Some combination of fiberglass & Carbon in 3 or more layers (beginning with a 2~3oz. layer of very plyable fiberglass) equaling about 12~14 oz. in total thickness.
2.) Extra reinforcements in the landing gear & tail mount area, add all formers (LG, Firewall & wing mounts) and do a wet lap joint while the fuselage is curing. Additional carbon tow can be added in corners if needed.
3.) Target weight with paint should be 7~8oz.
I am beginning the waxing process on the fuselage plug on, and will lay up the mold next week. So if you have any corrections to this formula, it isn't too late yet! My fuselage has a lot of curvature in it, so I think that will add to a natural stiffness in a composite structure, right? I am sure I will make some changes after test flights are completed, but this will definately give me a head start.
Thanks guys
< Message edited by Scorpion Racing -- 5/13/2008 1:18:52 AM >
Printable Version
All Forums >> RC Airplanes >> Composites Fabrication And Repair >> Quickie 500 Fuselage layup and mold building pics 
Quickie 500 Fuselage layup and mold building pics - 
I have the fuselage mounted on 3/4" wood, with 3/4" supports under 7 stations at points down the bottom to create the curves as well as in front of the firewall, and then mounted the parting board to this structure. I need to add some registration bumps and then lay up the mold on this. If all works out as planned, I should end up with a mold that looks quite close to yours. 
