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Old Jan 07, 2011, 05:11 PM
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United States, MA, Wilmington
Joined Jul 2004
208 Posts
shifting motors back,etc

I had to guess where to mount the motors, and the downside is that if i break a rotor blade I will be cutting in a hatch t access the rotor blade.
The motor and escs are heavy, and I think I set them too far back. I need to check denials CG mark compared to the 150mm back that i pencilled in... I am still too tail heavy
I need to carve out a bit more foam so the canopy will sit where it should. then probably coating the battery bay for strength and to add weight to the nose.
I am using stock gear but wheels from the eflite f-15, the gws ones are too skinny.
Kevin
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Old Jan 07, 2011, 05:24 PM
swede
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United States, UT, Vineyard
Joined Aug 2005
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Quote:
Originally Posted by photoz01 View Post
I had to guess where to mount the motors, and the downside is that if i break a rotor blade I will be cutting in a hatch t access the rotor blade.
We're all in the same boat on that one. There are a few who made custom hatches to access the motors and fans, but the directions have you seal everything in the frame.

Quote:
Originally Posted by photoz01 View Post
The motor and escs are heavy, and I think I set them too far back. I need to check denials CG mark compared to the 150mm back that i penciled in... I am still too tail heavy
Just for clarification, my CG is with the plane balanced right side up. I figure this is more of a high wing plane than a low wing, so I balanced right side up. For a typical WWII war bird with a low wing, you would balance upside down.

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Originally Posted by photoz01 View Post
I need to carve out a bit more foam so the canopy will sit where it should. then probably coating the battery bay for strength and to add weight to the nose.
That's a pretty good idea. I don't remember fixing it, but it looks like there is a repair on the forward fuse near the canopy. I must have snapped it somewhere along the line.
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Old Jan 07, 2011, 07:34 PM
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United States, MA, Wilmington
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208 Posts
adding weight

ok i just coated the nose with 15 minute epoxy then coated the inside of the battery bay, once it dries i will try to balance her again.
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Old Jan 07, 2011, 09:22 PM
It wasn't my fault!!
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USA, MI, Midland
Joined Oct 2004
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Originally Posted by denial15 View Post

Mine is balanced about 11 centimeters from the leading edge of the wing, measured next to the fuse. That's about 15-20mm from the rear edge of the angled wing spar slot.
Urgh.. I gave up with the 2 x 3s (4000mah) I had two oz stuffed in the pusher hole and it didn't make enough difference.. With the retracts, I'm thinking I'm heavy enough.

I have a "Blue" 2650mah that "just" squeezes in with minimal foam hacking.. and it balances right on the nail! So I think for maiden.. it's a good choice..

And it's still snowing.. so that wont be for a while yet
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Old Jan 07, 2011, 09:51 PM
swede
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United States, UT, Vineyard
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Quote:
Originally Posted by Headspin View Post
Urgh.. I gave up with the 2 x 3s (4000mah) I had two oz stuffed in the pusher hole and it didn't make enough difference.. With the retracts, I'm thinking I'm heavy enough.

I have a "Blue" 2650mah that "just" squeezes in with minimal foam hacking.. and it balances right on the nail! So I think for maiden.. it's a good choice..

And it's still snowing.. so that wont be for a while yet

What motors were you running again?
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Old Jan 09, 2011, 10:34 PM
It wasn't my fault!!
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The ones that came with the kit.. blues... 4600kv

I had 2 x 3s in parallel.. 11.1v 4000mah
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Old Jan 09, 2011, 11:21 PM
swede
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K
Quote:
Originally Posted by Headspin View Post
The ones that came with the kit.. blues... 4600kv

I had 2 x 3s in parallel.. 11.1v 4000mah

Keep your maiden flight short. I'll be surprised if you get over 3 min of flight time. (full throttle if you fly like me)
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Old Jan 11, 2011, 05:08 PM
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United States, MA, Wilmington
Joined Jul 2004
208 Posts
taxi test/engine run up

well I took my F-15 outside before dark and ran up the motors using my weaker/slightly puffed 4s 3700 25c rhino. MAN that thing sounded sweet.
my only problem was securing the nose wheel. this nose gear is definately made for those thin gws wheels, and I really dont have much room to secure a stopper to keep the nose wheel on. I have just a plastic cap on the wire and it needs to be glued in place. using the eflite wheels for their F-15 leaves very little room.
She looks and sounds good though. I just need a good day for those before flight pics!
I'm not using ailerons,just full flying stabs. My test flying field is a dirt parking lot that is going to be covered with 12-14 inches of snow starting late tonight, so it will be a few days before that gets plowed out for the maiden flight.
Kevin
MA
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Old Jan 11, 2011, 08:28 PM
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Brandon, Fl
Joined Mar 2005
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Good luck on the maiden - and hope the snow is short lived. Remember that a nose down attitude on the ground may look mean but she won't lift - the wings create too much down force. The 5'' spacer is necessary (and overlooked). Spool up evenly, steer straight, and she will know when to lift. Rotate evenly and she will be a sweet flyer.

Jim
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Old Jan 13, 2011, 08:53 PM
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United States, MA, Wilmington
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maiden postponed

Well, we ended up with 24 inches of snow, so I dont think the usual flying locations will be ready for a while, and I will be busy plowing some of that snow around for a few days.
Kevin
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Old Jan 14, 2011, 07:58 PM
It wasn't my fault!!
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USA, MI, Midland
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Originally Posted by photoz01 View Post
Well, we ended up with 24 inches of snow, so I dont think the usual flying locations will be ready for a while, and I will be busy plowing some of that snow around for a few days.
Kevin
lol.. I have a buddy who lives over there.. a few months ago (early November) he told me he shovelled 8 inches of "global warming" off his drive... And I thought Michigan was bad...

friggin lake snow just keeps on rollin in... be a few months for me yet.
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Old Jan 15, 2011, 06:25 PM
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United States, MA, Wilmington
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first flight

Well I got done plowing snow for the day and decided to take the F-15 to the test flight facility I like to use, I large dirt parking lot. The parking lot was in use for an antiques show so it was off to field number 2, a large paved lot of a mostly vacant aerospace facility. This area has a lot of light poles and a long building next to it. Its a good place to fly a proven flyable aircraft, but not many areas for a crash landing and recovering the pieces.

As I said earlier, we got 24 inches of snow, so the best part of the paring lot was not plowed out. What was plowed out still had a layer of packed snow, BUT I found a clear pavement strip that would be good for a take off and landing.
Checked control surfaces,-I did not build this with ailerons. Checked steering, she's holding straight, off she goes!! I didnt do anything crazy, no loops not even a roll, no high speed passes.
Just 5 or 6 times around the pattern, then one low approach to see how well she would glide, and then brought it in to land. It took longer to get on the ground then I expected but I kept feathering the throttle and tried to get a good flare. The way it flew when going slow made me feel like I didnt have to keep the speed up on landing. It came to rest on the hardpacked snow, but the touchdown was on the paved area where I wanted it to land!
I have a Rhino 4S 25C 3700 battery.
the edf's are the sapac 64mm same as eflite delta V 480 6 blade
the motors are a generic copy of the eflite 4000kv that go with the delta v 480 for 4S.
The esc's are 50-60 amp ones from hobby King with a turnigy bec.
I made this bird with all flying elevons and no ailerons.
Kevin
MA
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Old Jan 15, 2011, 06:44 PM
swede
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United States, UT, Vineyard
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Awesome. It's good to see it flies with your fans moved to the rear more. What did you have to do to get the balance right?
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Old Jan 15, 2011, 09:06 PM
It wasn't my fault!!
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USA, MI, Midland
Joined Oct 2004
793 Posts
Excellent.. well done finding a window in all this bad weather..
We got another 4" last night and the wind was up and down all day..

I'm enjoying looking at mine though right now.. I would hate to crash it because I rushed the first flight.

Anyway, great to hear your maiden was a success.. Congrats
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Old Jan 15, 2011, 10:33 PM
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United States, MA, Wilmington
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added weight

I had said earlier that I had guessed wrong and put the motors too far back, but I knew it was only a guess.

I added weight to the nose, I work for a Water Department and we use these tiny lead type disks that have 2 tiny holes through each disk that a security wire is passed through and attached to water meters, as a tamper deterrent.
I used about 10 of these. Some are epoxied(heavily) to the inside of the battery bay, and some I carved out a spot in the canopy to mount them under the instrument panel,-big risk there though, mounting weight to a removeable part of the plane,- losing the canopy in flight would be disastrous!

I guess I actually proved that I could have put a larger battery in!
Kevin
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