Skymaster F-18 build thread
08-02-2004, 08:01 PM
#27
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RE: Skymaster F-18 build thread
Hi Ralph,
No, I won't be at Fresno. Not sure I'd get the bug done by then, but even if I do there's a pattern meet in Hollister I'm going to. I should be at AZ Jets though.
No, I won't be at Fresno. Not sure I'd get the bug done by then, but even if I do there's a pattern meet in Hollister I'm going to. I should be at AZ Jets though.
08-02-2004, 11:28 PM
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RE: Skymaster F-18 build thread
ORIGINAL: SAP_2000
Yes, me.
I have the same problem, and don't know what to do about it...
Anyone got a solution to get the mains to lock in the up position?
ORIGINAL: Nick Yuhasz
Observation about the Main Gear retracts: I'm just getting ready to mount the retracts and notice in the "up" position (wheels inside airframe) that the main wheels hit the wood plate inside and won't allow the retract to "lock" in the up position. It appears I will have to add a plywood shim to the retract mounting plates to raise the retract to allow the wheel to fully go up into the fuse and to allow the retract to lock.
Anyone else see this happening?
Observation about the Main Gear retracts: I'm just getting ready to mount the retracts and notice in the "up" position (wheels inside airframe) that the main wheels hit the wood plate inside and won't allow the retract to "lock" in the up position. It appears I will have to add a plywood shim to the retract mounting plates to raise the retract to allow the wheel to fully go up into the fuse and to allow the retract to lock.
Anyone else see this happening?
I have the same problem, and don't know what to do about it...
Anyone got a solution to get the mains to lock in the up position?
Take look the pictures, this is what we did for the question you concerned.
We’ve checked out a few of the F-18s, and there is a potential that the main gear will be unable to lock in the up position when using the Robart 630. The wheel will hit the wood plate, enabling the wheel to lock in the upright position.
All you will have to do is cut an opening on the wood plate to allow the wheel to fit in a little more so the retract will lock. Please refer to the picture I have included. We’ve already notified Skymaster regarding this issue, and this problem will be eliminated on our next shipment of F-18c.(and F-18E too
)
08-03-2004, 06:11 AM
#29
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RE: Skymaster F-18 build thread
ORIGINAL: George-RCU
Nice job Dbarrym! [sm=thumbup.gif]
I found some of the same issues with the Gripen. The ONLY servo that would work for the rudder was the DS 168. I actually made a mount for it and Hysol'ed it in. It more or less is the same exact concept as your mounting except I may have slightly more glueing surface.
Nice job Dbarrym! [sm=thumbup.gif]
I found some of the same issues with the Gripen. The ONLY servo that would work for the rudder was the DS 168. I actually made a mount for it and Hysol'ed it in. It more or less is the same exact concept as your mounting except I may have slightly more glueing surface.
I used a 3421 on my rudder mounted in the fuselage at the base of the fin. Worked great. I'm pretty sure Jeremy Ferguson did the same.
08-09-2004, 11:08 PM
#31
RE: Skymaster F-18 build thread
OK, I've spent most of the last week in paint and seam filling, but took a few pics of the misc. little stuff needed.
Here's the rear speedbrake/hatch mounting, I used some 1/8" brass tubes for the forward hatch pins, and glued a 1/4"x3/8"x1/2" spruce block to the top of the rear former, then drilled through the brake and used a 5/8" button head screw as a rear hold-down.
I did end up cutting clearance holes for the main wheels, though I could have kept the 1/8" wedge I had used initially. A 3/4" hole saw, 90 degree hand grinder and 120 grit sanding drum comes in very handy here...
Barry
PS - The mis-match in color is because I had already painted the hatches; the fuse was still in grey gelcoat.
Here's the rear speedbrake/hatch mounting, I used some 1/8" brass tubes for the forward hatch pins, and glued a 1/4"x3/8"x1/2" spruce block to the top of the rear former, then drilled through the brake and used a 5/8" button head screw as a rear hold-down.
I did end up cutting clearance holes for the main wheels, though I could have kept the 1/8" wedge I had used initially. A 3/4" hole saw, 90 degree hand grinder and 120 grit sanding drum comes in very handy here...
Barry
PS - The mis-match in color is because I had already painted the hatches; the fuse was still in grey gelcoat.
08-09-2004, 11:57 PM
#33
RE: Skymaster F-18 build thread
Here's how I decided to keep the main tank in place - I used some RX foam on top to wedge the tank in and then used a piece of 3/8" thick x 1" high balsa strip to brace the tank in place laterally. The balsa brace is lightly Gooped in place; the saddle tanks are also Gooped in place to the engine mount rails. I "T'ed" all the fuel and air lines in front of the main tank. Note the safety wired connections.
I have put a break in the fuel line(s) at the fuse joint allowing 3" of so of slack, doing the same for the air lines (using Robart quick-disconnects) and servo cables to alllow the nose to come off for shipping. I also fabricated a half-former from 1/8" ply that mounts just at the rear of the nose gear strut opening (in the front fuse half), and tie-wrapped my 8 oz. header tank to it.
Now to install the pipe, bypass, P120 and associated plumbing, then bolt the nose on...
barry
I have put a break in the fuel line(s) at the fuse joint allowing 3" of so of slack, doing the same for the air lines (using Robart quick-disconnects) and servo cables to alllow the nose to come off for shipping. I also fabricated a half-former from 1/8" ply that mounts just at the rear of the nose gear strut opening (in the front fuse half), and tie-wrapped my 8 oz. header tank to it.
Now to install the pipe, bypass, P120 and associated plumbing, then bolt the nose on...
barry
08-10-2004, 12:01 AM
#34
RE: Skymaster F-18 build thread
Buck, bro, it was watching your high AOA approaches with the big Bug that convinced me I don't need no stinking speedbrake...just need to learn "pitch is speed, throttle is altitude" mantra....repeat after me....
barry
barry
08-10-2004, 12:06 AM
#35
RE: Skymaster F-18 build thread
Ha!! you only think that speed brake is non=functioning! I actually release a set screw when I install my main hatch.
ever wonder why I keep the plane up as high as I do when I do high alpha?
and now you know the rest of the story.
do it, do it, do it
ever wonder why I keep the plane up as high as I do when I do high alpha?
and now you know the rest of the story.
do it, do it, do it
08-10-2004, 12:54 AM
#36
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RE: Skymaster F-18 build thread
Speaking of high AOA, there is a video of the F-18 twin for sale here on Rcu that show him dragging the tailcones on touchdown. Very impressive.
Sorry to hack your thread!
Sorry to hack your thread!
08-10-2004, 06:59 PM
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RE: Skymaster F-18 build thread
ORIGINAL: SDCrashmaster
Buck, He said cones...not stones.
We already know those are all marked up with all the draggin' they've been through.
Buck, He said cones...not stones.
We already know those are all marked up with all the draggin' they've been through.
LOL!!!!!
08-14-2004, 03:36 AM
#43
RE: Skymaster F-18 build thread
OK, not a whole lot of obvious progress as I've been filling and painting this week, and researching my trim scheme. I'm about ready for the final assembly and equipment install now. I will be fiinishing my bug in the scheme of the local Marine "Red Devils" VMFA-232 squadron...appropriate as my "home base" flying site is MAS Miramar. I sanded the airframe down with 320 grit and sprayed it with PPG K-36 primer, thinned 70%, then smoothed out with the dark grey (fine) 3M Scotch-Brite scuff pads. I am making my own decals using some Ink-Jet water slide decal paper, weathering with 3M control powder, then clearing with 2060 flat clear.
Here's how she will look when done...
Barry
Here's how she will look when done...
Barry
08-14-2004, 03:43 AM
#44
RE: Skymaster F-18 build thread
The struts provided by Skymaster are excellent, machined from aluminum bar stock, and very scale-appearing. However, they are bare aluminum and need to be painted gloss white for a scale appearance, and to protect from corrosion (as we are very close to the coast here).
Bare metal should be cleaned and prepped for good paint adhesion, so I first "washed" the struts in acetone. Out of laziness, I decided not to disassemble them, but just masked off the moving parts and then sprayed them with a self-etching metal primer. After the primer cured, I sprayed them with a single-part white auto enamel from a spray can.
Barry
Bare metal should be cleaned and prepped for good paint adhesion, so I first "washed" the struts in acetone. Out of laziness, I decided not to disassemble them, but just masked off the moving parts and then sprayed them with a self-etching metal primer. After the primer cured, I sprayed them with a single-part white auto enamel from a spray can.
Barry
08-14-2004, 01:05 PM
#48
RE: Skymaster F-18 build thread
I noticed that the fasteners (set screw and pinch bolts) on the gear is a mixture of metric and SAE. Make sure you loctite where appropriate and grind flats onto the nose wheel steering arm shaft and nose wheel axle.
I did have to add a couple of washers to each side of the nosewheel axle to remove some excess play, 2 medium thick #10 washers per side did the trick. On the main gear, check/Loctite the bolts on the knuckle joints. When installing the main wheels, make sure the axle length on both sides is equal - these are disc brakes and if there is a difference on either side, you may get unequal braking on initial application. Also check the bolts holding the wheels together, I had a couple loose ones.
Barry
I did have to add a couple of washers to each side of the nosewheel axle to remove some excess play, 2 medium thick #10 washers per side did the trick. On the main gear, check/Loctite the bolts on the knuckle joints. When installing the main wheels, make sure the axle length on both sides is equal - these are disc brakes and if there is a difference on either side, you may get unequal braking on initial application. Also check the bolts holding the wheels together, I had a couple loose ones.
Barry
08-17-2004, 06:16 PM
#49
RE: Skymaster F-18 build thread
I'm deep into the gear-up process now, basically trying to get as much installed as possible before I bolt the nose on. I loaned my camera out so no photos for now.
All the servos are installed, pushrods made and installed, all the servo extensions are installed as well. Here's what I used for extensions:
Fins: 3" extension on each DS-168 (JR, why don't you just make the leads 3" longer? they are ridiculously short now), then a 36" HD extension
Stabs: 36" HD extension on each
Wings: No extension needed for flaps, 12" HD on each aileron
24" HD extensions for the aileron and flap servo cables in the fuse
I routed the extensions along the top of the fuse and Gooped some tie-wrap hold downs every 6" from the rear forward to the LE of the wing, then routed the cables out the nose along the sides of the main tank. This leaves about 6" of excess cable hanging out the front of the rear half of the fuse. I'll create a service loop with the excess cable when the front nose half is bolted on.
I also installed the retracts and nose wheel steering servo, using nylon coated Kevlar cord for the nose steering cables. No rocket science here. I T'd the air lines in front of the main tank, and ran about 3" of line out of the T's to Robart quick-release fittings.This way, I can remove the nose quickly and without cutting any air lines or messing with servo extensions going to the RX.
One note regarding the pushrods - the kit includes pushrods for the stabs and (I think) the rudders. However on ARF's I prefer to make my own using top quality hardware and rods. Only after installing the stab pushrods and checking the play in the stab did I notice that the holes in the elevator horns are 3/32"...
End result, I used the kit-provided clevises on the horn end, rather than making some brass bushings for the clevises. I cleaned and silver-soldered them on to the pushrods I'd already made (the threads on the kit clevises are metric), they were an easy fit on the large 4-40 rods. FWIW the kit supplied ahrdware is excellent quality but I did not want to drill a 2/32" hole in my servo arms.
FWIW, the stock servo arms work great on the fins, using the next-to-last hole. I made the rudder pushrods from 2-56 rod (it is all of 2" long) and 4-40 everywhere else. Stabs, flaps and ailerons use the HD JR arms (#JRPA215), using the outer hole for flaps and stabs and the next-to-last hole for the ailerons. This puts the throws at the recommended high rates without having to push ATV's beyond 100-110%, keeping control resolution near max.
One note, it is much easier to install the stab servos using socket-head servo screws. I also replaced the servo arm screws with metric cap head types (M3 thread x 6MM long).
Tonight I'll finish the engine and pipe install and run fuel and turbine cables.
Since it looks like I will not be going to GSW after all, the new unveiling target is Fresno, so I may take a few weeks off while I wait for paint masks and the like to arrive. I bought some inkjet decal paper and am going to try to do some of my own graphics from the photos I have.
Barry
All the servos are installed, pushrods made and installed, all the servo extensions are installed as well. Here's what I used for extensions:
Fins: 3" extension on each DS-168 (JR, why don't you just make the leads 3" longer? they are ridiculously short now), then a 36" HD extension
Stabs: 36" HD extension on each
Wings: No extension needed for flaps, 12" HD on each aileron
24" HD extensions for the aileron and flap servo cables in the fuse
I routed the extensions along the top of the fuse and Gooped some tie-wrap hold downs every 6" from the rear forward to the LE of the wing, then routed the cables out the nose along the sides of the main tank. This leaves about 6" of excess cable hanging out the front of the rear half of the fuse. I'll create a service loop with the excess cable when the front nose half is bolted on.
I also installed the retracts and nose wheel steering servo, using nylon coated Kevlar cord for the nose steering cables. No rocket science here. I T'd the air lines in front of the main tank, and ran about 3" of line out of the T's to Robart quick-release fittings.This way, I can remove the nose quickly and without cutting any air lines or messing with servo extensions going to the RX.
One note regarding the pushrods - the kit includes pushrods for the stabs and (I think) the rudders. However on ARF's I prefer to make my own using top quality hardware and rods. Only after installing the stab pushrods and checking the play in the stab did I notice that the holes in the elevator horns are 3/32"...
End result, I used the kit-provided clevises on the horn end, rather than making some brass bushings for the clevises. I cleaned and silver-soldered them on to the pushrods I'd already made (the threads on the kit clevises are metric), they were an easy fit on the large 4-40 rods. FWIW the kit supplied ahrdware is excellent quality but I did not want to drill a 2/32" hole in my servo arms.
FWIW, the stock servo arms work great on the fins, using the next-to-last hole. I made the rudder pushrods from 2-56 rod (it is all of 2" long) and 4-40 everywhere else. Stabs, flaps and ailerons use the HD JR arms (#JRPA215), using the outer hole for flaps and stabs and the next-to-last hole for the ailerons. This puts the throws at the recommended high rates without having to push ATV's beyond 100-110%, keeping control resolution near max.
One note, it is much easier to install the stab servos using socket-head servo screws. I also replaced the servo arm screws with metric cap head types (M3 thread x 6MM long).
Tonight I'll finish the engine and pipe install and run fuel and turbine cables.
Since it looks like I will not be going to GSW after all, the new unveiling target is Fresno, so I may take a few weeks off while I wait for paint masks and the like to arrive. I bought some inkjet decal paper and am going to try to do some of my own graphics from the photos I have.
Barry
08-18-2004, 09:57 PM
#50
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RE: Skymaster F-18 build thread
Great job Barry!
Keep the good work up. I'm using 4-40 hex screws for my elevator servo mounts too. Much easier to get too.
Here is a link to My friend Woody's Skymaster f-18 maiden flight. The gear not locking at the end of the flight was due to air-load against the landing gear coming down into the air stream. They were the new low-profile springair 402's. With the addition of some balance springs there should be no additional down locking issues. The damage was some very minor scratching thats all.
http://www.hawaiijets.com/aircraft/f-18/f-18.htm Video is 35mb using windows media player 9. The video should stream.
Keep the good work up. I'm using 4-40 hex screws for my elevator servo mounts too. Much easier to get too.
Here is a link to My friend Woody's Skymaster f-18 maiden flight. The gear not locking at the end of the flight was due to air-load against the landing gear coming down into the air stream. They were the new low-profile springair 402's. With the addition of some balance springs there should be no additional down locking issues. The damage was some very minor scratching thats all.
http://www.hawaiijets.com/aircraft/f-18/f-18.htm Video is 35mb using windows media player 9. The video should stream.