Yellow F-18 single build
#1
This is my first jet. All inputs will be greatly appreciated. Here are some pics of what I have done so far. My brother buddude8 is also working on the same plane. THIS REALLY IS A NICE KIT FOR THE MONEY.
#7
Dang,
How long have you been working on this?? Looks awesome!
Here's a tip for next time, or for someone who hasn't gotten to that part yet:
On the control-horn hard-points in the ailerons and flaps--rather than cutting the rectangular holes then removing the balsa and foam to glue the plate in, install them before you glue the balsa leading edge on. Take a small-diameter hot wire (I use the back end of those 12" 2-56 rods that I've got all over the place) and melt a slot in the foam. Don't do it in the middle, to it on the appropriate side against the inside of the sheeting. It doesn't really matter if the hole is oversized a bit because you're gonna fill it with epoxy. Once you've got your slot, test fit the plate. When it fits loosely, fill up the slot with 15 or 30 minute epoxy (5-minute if you're really quick on the draw or you've done it successfully on one), then slide the plate into the slot. Wipe off the epoxy that squeezes out and make sure it's as clean as possible (I use masking tape on the wood to keep the glue off). Let it cure, then face the leading edge with your sanding bar before you glue on the leading edge balsa per instructions. Take a Sharpie and mark where the plate is! Otherwise, you're gonna be in the bathroom with the lights off, shining a Maglite through it to see where the dark spots are (ask me how I know this...).
It's faster, easier and you don't have to try to sand hardwood down to be flush with balsa. It'll actually take you less time to do it than it took me to write this
How long have you been working on this?? Looks awesome!
Here's a tip for next time, or for someone who hasn't gotten to that part yet:
On the control-horn hard-points in the ailerons and flaps--rather than cutting the rectangular holes then removing the balsa and foam to glue the plate in, install them before you glue the balsa leading edge on. Take a small-diameter hot wire (I use the back end of those 12" 2-56 rods that I've got all over the place) and melt a slot in the foam. Don't do it in the middle, to it on the appropriate side against the inside of the sheeting. It doesn't really matter if the hole is oversized a bit because you're gonna fill it with epoxy. Once you've got your slot, test fit the plate. When it fits loosely, fill up the slot with 15 or 30 minute epoxy (5-minute if you're really quick on the draw or you've done it successfully on one), then slide the plate into the slot. Wipe off the epoxy that squeezes out and make sure it's as clean as possible (I use masking tape on the wood to keep the glue off). Let it cure, then face the leading edge with your sanding bar before you glue on the leading edge balsa per instructions. Take a Sharpie and mark where the plate is! Otherwise, you're gonna be in the bathroom with the lights off, shining a Maglite through it to see where the dark spots are (ask me how I know this...).
It's faster, easier and you don't have to try to sand hardwood down to be flush with balsa. It'll actually take you less time to do it than it took me to write this
#8
Thanks for the tip. It would have been much easier to do it that way. I started this plane in late july. I want to have it ready to fly by Dec. when my brother comes out. I have never ran a ducted fan engine. How do you know when you have the needle set right ?
Thanks John
Thanks John
#11
Well,
For me, it's always been more of a 'feel' or 'sound' than a number. The problem is that those engines are so very easy to screw up (with a quickness) if you do it wrong. That's why I was never willing to buy them used (even "bench run only").
I start with 1-3/4 turns out from closed on the high end, and close the low-end needle down 1/4 from the factory setting. The book says the low end is factory tuned, but that's BS. It's way too fat out of the box on a Dynamax.
I prime it and start it at about 1/4 throttle and slowly run it up to full. It should be so fat (rich) that it barely stays running. I pinch the line briefly and it should jump way up in RPMs. I close the high-end needle a couple clicks at a time, pinching it in between to see where in the high-to-low 'spectrum' I am. I keep doing that until the engine is screaming, but still briefly jumps up about 5% in RPMs with a brief pinch. If it holds steady RPMs or bogs down (AT ALL), it's too lean.
Once I have the high-end RPMs at what sound like about 95% of potential, I throttle down and set the low-end. At an idle setting, the engine should only cycle up in RPMs about 15% before quitting with the low-end needle set right. If it dies right away at the pinch, it's too lean. If it runs forever, or cycles up in RPM dramatically, it's probably too fat. Once it sounds right and can run reliably for at least a minute, I test the transition. If the low-end is set up properly, the engine should go from idle to full speed instantly if it hasn't been idling for more than 10 seconds or so. If it's been idling for a while, it may hesitate briefly before going on the pipe. Funny thing is, cutting out when you try to throttle up quickly can be an indication of a too-fat or too-lean low-end setting. You have to play with it.
Once it's sounding right, fly it. It doesn't need to run rich or at idle for a long time like some other types of engines. If you land and the head is significantly discolored, richen it up. Some people will tell you that carmelization is normal or just a matter of what kind of oil is in your fuel, but the most longeve engine I had was on O.S. .91 that ended up with about 300 run cycles on it before it went to the Lord, and it was bright silver. Not black--not brown or whatever. And believe me, it flew those Starfires around such that you couldn't have accused it of being too rich.
Hope this helps.
For me, it's always been more of a 'feel' or 'sound' than a number. The problem is that those engines are so very easy to screw up (with a quickness) if you do it wrong. That's why I was never willing to buy them used (even "bench run only").
I start with 1-3/4 turns out from closed on the high end, and close the low-end needle down 1/4 from the factory setting. The book says the low end is factory tuned, but that's BS. It's way too fat out of the box on a Dynamax.
I prime it and start it at about 1/4 throttle and slowly run it up to full. It should be so fat (rich) that it barely stays running. I pinch the line briefly and it should jump way up in RPMs. I close the high-end needle a couple clicks at a time, pinching it in between to see where in the high-to-low 'spectrum' I am. I keep doing that until the engine is screaming, but still briefly jumps up about 5% in RPMs with a brief pinch. If it holds steady RPMs or bogs down (AT ALL), it's too lean.
Once I have the high-end RPMs at what sound like about 95% of potential, I throttle down and set the low-end. At an idle setting, the engine should only cycle up in RPMs about 15% before quitting with the low-end needle set right. If it dies right away at the pinch, it's too lean. If it runs forever, or cycles up in RPM dramatically, it's probably too fat. Once it sounds right and can run reliably for at least a minute, I test the transition. If the low-end is set up properly, the engine should go from idle to full speed instantly if it hasn't been idling for more than 10 seconds or so. If it's been idling for a while, it may hesitate briefly before going on the pipe. Funny thing is, cutting out when you try to throttle up quickly can be an indication of a too-fat or too-lean low-end setting. You have to play with it.
Once it's sounding right, fly it. It doesn't need to run rich or at idle for a long time like some other types of engines. If you land and the head is significantly discolored, richen it up. Some people will tell you that carmelization is normal or just a matter of what kind of oil is in your fuel, but the most longeve engine I had was on O.S. .91 that ended up with about 300 run cycles on it before it went to the Lord, and it was bright silver. Not black--not brown or whatever. And believe me, it flew those Starfires around such that you couldn't have accused it of being too rich.
Hope this helps.
#12

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From: Poway, CA
Very nice, keep the build going. Im sure it will help a lot of other people out there. Have you installed the inlet yet, if not let Shaun give you some tips on that, and then put them in this build thread for everyone to see. Great job.
#18

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From: Placentia,
CA
ORIGINAL: deltron
Where did you find the Blue Angel pilot?
Dan
Where did you find the Blue Angel pilot?
Dan
#19

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From: Placentia,
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they still have them here is the link. the price has gone up since we bought them. you can also get the george bush pilot there too both are 39.99 and they come with the helmet that some of the jet suppliers are selling for over 30 bucks themselves.
http://www.kbtoys.com/genProduct.htm...7/INstock/Y/D/
http://www.kbtoys.com/genProduct.htm...7/INstock/Y/D/
#20
Installing the inlet duct. Its nice that yellow cuts the opening for you. I only had to remove a small amount of material to get a good fit. I glassed the inside with 6 oz cloth, then I taped the inlet and glued it from the inside.
#22
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From: SANTIAGO, CHILE
ORIGINAL: buddude8
they where purchased at kbtoys online for 19.99 They where a limited production of these made by blue box toys
ORIGINAL: deltron
Where did you find the Blue Angel pilot?
Dan
Where did you find the Blue Angel pilot?
Dan

#23

Hi Speed,
Looking good. May I suggest that before you fly your F18 that you check the AOA on the wing to ensure that it is positive and lengthen you noseleg as much as possible to help this model "fly off". You might want to consider this before finalising the length of your nose door.
PM me if you would like further information.
Regards,
Craig.
Looking good. May I suggest that before you fly your F18 that you check the AOA on the wing to ensure that it is positive and lengthen you noseleg as much as possible to help this model "fly off". You might want to consider this before finalising the length of your nose door.
PM me if you would like further information.
Regards,
Craig.


