F-18 Foam Build
06-25-2011, 08:33 AM
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RE: F-18 Foam Build
The Fans are pusher. Motor in front. I believe they are WM400 fans from Ductedfans dot com. They happened to be included with the kit. I tested them with my power system, a day ago. 38,000 rpm at 710 watts at 53% throttle. They won't hold up to the Cyclone CS480-2500-32 1400watt motors and 6 cell packs. The specs mentioned are from the Turnigy Superbrain 100 amp 12 cell max data logger equiped ESC. These fans are coming out, to be replaced with Wemotec Minifan Pro rotors on CNC shrouds from Extreme RC in Australia. Alloy shrouds, balanced rotors, 1400 watt 2500kv motors and 6 cell Zippy lipoly 2650 mah 40c packs. The F-18 seems to weigh in at 6.5 pounds, plus. AUW with retracts and no paint, just trim scheme, will be 7.5 or 8 pounds, hence the need for very good 70mm fan units. 90mm fans weigh too much, the F-18 would have to be fibreglassed to stand 2 90 mm units. I will attach a pic of the 3 blade fans in the next post...
06-26-2011, 04:47 PM
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RE: F-18 Foam Build
I had to change the torque-tube for the stabs. The first gluing stuck the rod to the bearing. The second, I broke the rod flexing it too much to try to adjust the stabs while the epoxy was still flexible. Third times a charm. The rod was re-located on the ply inserts into a new hole(s). the old rod was sanded off flush.
Some views of the canopy hatch and hatch-latch are on here too.
The bearing tubes for the stabilzer torque-rod are aluminum run in hardwood blocks. The blocks help to align top and bottom fuselage halfs.
Some views of the canopy hatch and hatch-latch are on here too.
The bearing tubes for the stabilzer torque-rod are aluminum run in hardwood blocks. The blocks help to align top and bottom fuselage halfs.
06-28-2011, 11:32 PM
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RE: F-18 Foam Build
I have the elevators servos in. One of them a CS 929 MG, the other a DS 929 MG. The normal rotation is reversed, so no modifications to one servo rotation was needed. The Anaolg and digital servos have oposite rotation, but be careful mixing digital and analog servos only do it if you know what you're donig.
Looking down the intake, with no ducting,,hmmmmwhere to put the electracts? Plenty of room.
Center of gravity discrepancy.
I'm looking at the overall airframe now.
The rails for the mains will mount on ply, 20mm by 10mm rails, at least 250mm long.
Looking down the intake, with no ducting,,hmmmmwhere to put the electracts? Plenty of room.
Center of gravity discrepancy.
I'm looking at the overall airframe now.
The rails for the mains will mount on ply, 20mm by 10mm rails, at least 250mm long.
06-29-2011, 02:12 PM
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RE: F-18 Foam Build
Jepe jet webiste http://www.jepe.org/indek.htm
[link=http://www.jepe.org/indek.htm]Jepe[/link]
The F-18 is a Jepe, I think, from Ductedfans.com
I got a photo of the CG location from that website. I'll confer with Morris et al @ DF to see if the flight CG of 15.5 cm from the le joint is better. The Jepe site recommends 5 cm.
I inserted Hobby City site canopy latches, and carbon tube to catch the metal pin, reinforcing the styrofoam.
[link=http://www.jepe.org/indek.htm]Jepe[/link]
The F-18 is a Jepe, I think, from Ductedfans.com
I got a photo of the CG location from that website. I'll confer with Morris et al @ DF to see if the flight CG of 15.5 cm from the le joint is better. The Jepe site recommends 5 cm.
I inserted Hobby City site canopy latches, and carbon tube to catch the metal pin, reinforcing the styrofoam.
06-29-2011, 02:23 PM
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RE: F-18 Foam Build
phoytos of the latches.
The canopy and liner will be adhered to the hatch. Magnets on canopies allow them to dislodge in flight. I want to add a pilot and instrument panel (just a photo)
The canopy and liner will be adhered to the hatch. Magnets on canopies allow them to dislodge in flight. I want to add a pilot and instrument panel (just a photo)
06-29-2011, 03:15 PM
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RE: F-18 Foam Build
Power system consists of Cyclone CS480-2500-32 motors, Turnigy TZ85a ESC's and Zippy Lipoly 2650 mah 6s 40c batteries, and a bec from Turnigy that's an 8 amp, since I'll be using heavy duty electracts, for the landing gear. Still have not determined if I'll do gear doors. Wing servos here as well, ailerons only. (no flap, and no le slat)
Carbon Fibre tube to be added. As well as a carbon fibre dowel, inside the carbon tube. Light stuff. Might as best make it strong.
Carbon Fibre tube to be added. As well as a carbon fibre dowel, inside the carbon tube. Light stuff. Might as best make it strong.
06-29-2011, 06:07 PM
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RE: F-18 Foam Build
Another Trial fit...still internal work to be done. Splicing servo leads, ducting, mounting ESC's in the ducting, locating battery mounting position and securing batteries.
06-29-2011, 06:42 PM
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RE: F-18 Foam Build
[link]http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14838[/link]
I look for the mains and possibly the nose retracts...here...good for 4 kilo ( about 9 lbs. ) and the jet is 7 to 7.5
I look for the mains and possibly the nose retracts...here...good for 4 kilo ( about 9 lbs. ) and the jet is 7 to 7.5
07-03-2011, 12:04 AM
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RE: F-18 Foam Build
it's made by Jepe, or at the least Jepe has them, and has modified versions. I got mine from Ductedfans.com To help you find it, here's the link, because the site is a bit difficult to navigate...
[link=http://www.ductedfans.com/F_18_Large_Foam_EDF_Jet_RC_Ductedfans.com.html]Big Foam F-18 Ductedfans dot com[/link]
Since the bird is light, with a lower wing loading, I use two 70mm high power fans. at the weight with 70mm fans, it's likely to be a floater. If it's powered up with 90mm fans it becomes a bigger project, since it gets ALOT heavier. Glassing, ducting, heavier fan unit motors, big batteries, etc.
I chose 70mm to keep it light and slower. Lots of capacity in the batteries for long flights too.
[link=http://www.ductedfans.com/F_18_Large_Foam_EDF_Jet_RC_Ductedfans.com.html]Big Foam F-18 Ductedfans dot com[/link]
Since the bird is light, with a lower wing loading, I use two 70mm high power fans. at the weight with 70mm fans, it's likely to be a floater. If it's powered up with 90mm fans it becomes a bigger project, since it gets ALOT heavier. Glassing, ducting, heavier fan unit motors, big batteries, etc.
I chose 70mm to keep it light and slower. Lots of capacity in the batteries for long flights too.
07-03-2011, 01:01 AM
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RE: F-18 Foam Build
I'm working on the ducting. Rubber bands provide the helping hands, tape in though scrapes. The forward ducts will be rolled posterboard, about double thickness, and glued to provide stiffness for the negative pressure involved.
The afterward ducts have to be split to assemble over the stabilizer rod bearing tubes. I split paperboard tube, at the latitute, not longitudinally, since the halves can be rolled that way. A top and bottom longitudinal split would involve fibreglass ducts, cut by dremel and the paper ducts can be split by, some in front of the bearings, some behind, with a clever fit. I'm still worrying over power loss from turbulence. Anyone have any thoughts? to smooth out the flow?
The afterward ducts have to be split to assemble over the stabilizer rod bearing tubes. I split paperboard tube, at the latitute, not longitudinally, since the halves can be rolled that way. A top and bottom longitudinal split would involve fibreglass ducts, cut by dremel and the paper ducts can be split by, some in front of the bearings, some behind, with a clever fit. I'm still worrying over power loss from turbulence. Anyone have any thoughts? to smooth out the flow?
08-14-2011, 10:27 PM
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RE: F-18 Foam Build
Trial assy...but still, main landing gear struts to construct, and nosegear strut construction. I also gotta send thanks to Vic W. for his help on the F-15. Everything on the F/A-18 is on hold, til inspiration for the l/g hits. I refuse to finish this jet with no landing gear. No fixed gear either. I have the electritracts, just working out the struts is a problem. I want to use a trailing link like the full size.
08-30-2011, 09:01 PM
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