Kfx 201 - Page 2 - RC Groups
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Jan 08, 2018, 08:30 AM
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elmagnificado's Avatar
I was thinking the same thing about the dirt right after I posted. It was almost 1 in the morning. I'll work on a version with the prop facing up.
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Jan 08, 2018, 04:37 PM
I Look, Listen, and Learn
Timbo383's Avatar
Quote:
Originally Posted by elmagnificado
I was thinking the same thing about the dirt right after I posted. It was almost 1 in the morning. I'll work on a version with the prop facing up.
With the prop facing up the motor could be damaged easier on bad belly landings.
What you can do is make a large version and use it as a flying lawnmower and trim the tall patches of grass.
Jan 08, 2018, 08:36 PM
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elmagnificado's Avatar
Ha! I think you're on to something.
Feb 12, 2018, 12:26 AM
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elmagnificado's Avatar

Progress


Got a baby sitter and finally made some progress on this thing. Didn't have time to take build pics, but was able to get a few pics after gluing it all together. Still need to put the rest of the guts in there, but I was able to get the motors on and a glide test in.

Went through my stockpile of motors and found a couple 1400 kv ebay jobs, so I decided to go with an in-line dual prop configuration with a couple 8x4's and 40A esc's. I did a quick thrust test on a 2200mah 3s (hold the tip and let her rip) and she can definitely go vertical, no problem. I recently got a couple 4s's, so I might see what she can do on those after I get used to how she flies. I only had matching props in that size so I might have to order some counter rotating props. but the torque roll wasn't too bad during the the thrust test with a 40inch WS. Not sure if she'll fit in the car! ;-).

Hope to finish her in the next couple days and get a maiden in before the end of the week.
Last edited by elmagnificado; Feb 12, 2018 at 12:44 AM.
Feb 12, 2018, 05:44 AM
I Look, Listen, and Learn
Timbo383's Avatar
Nice, looking good. Interesting motor set up, didn't notice it till I got home and was able to look at the pics at a larger scale than on my cell phone. Any disadvantages to running them like that?
Last edited by Timbo383; Feb 12, 2018 at 07:01 PM.
Feb 12, 2018, 06:09 PM
skumgummi dave
Love the looks of that. Good luck on the first flight...

Dave-
Feb 18, 2018, 09:49 AM
Registered User
elmagnificado's Avatar
Finished her up and had to wrangle her into the trunk. Didnt realize I bend the elevator doing that. Had her in the car for almost a week then finally had time and weather to fly but it was windy with 15-20 MPH gusts. I thought she'd be ok being so big and all, but she's light and it was throwing her around quite a bit. Also had to adjust the cg a couple times.

Sorry no maiden vid. Everything went OK for a couple safe short flights, but as soon as I let her rip, the bent elevator started to flutter like crazy and became hard to control. I also have a lot of elevator material in front of the hinge. I had to put her down kind of hard. The elevator was starting to rip the hinge and I had no elevator control on that side.

Should get to some repairs and add more reinforcement in a few days. Have some counter rotating props coming in the mail in a couple days also so I'll try and get some video when I get her out again.
Feb 18, 2018, 01:48 PM
skumgummi dave
Feb 18, 2018, 03:53 PM
Retired CAD guy
birdofplay's Avatar
Reinforce the elevon hinges with Blenderm , maybe on Both sides.

Also with a cf strip across them or even embedded edgewise if possible.

Can't tell but the Forward of hinge line doesn't look like its in the Prop stream
but rather outside the rudders.

I have lots of that in the prop stream on my F-22

Be sure you have supports for the push rods it they are long.

This could be built with a combo of White foam and Black/Grey foam.

I found that works well and looks nice an contrasty
Mar 03, 2018, 01:09 AM
Registered User
elmagnificado's Avatar

Maiden #2


Ok, I got her patched up and went for another go. I put some CF rod in the elevons for rigidity and cut away some extra material between the ailerons and elevons in case there was some weird air flow produced. I also figure this would allow more airflow up to the v-tail for more stability in high alpha. I couldn't wait for the counter rotating 8" props so I slapped a 3 blade 6"x4" on 2200kv in the back (still the original 8" on 1400 kv in the front). I read somewhere that counter rotating props are a little more efficient with a faster prop in the back, and since that's all I had, I went with it.

I posted some vids if anyone is interested. They are totally unedited and kind of long with me talking to myself thrown in there for good measure . I tend not to finish my sentences for even more "suspense". The last vid shows a good inverted flight on a 4s right into the hidden hill (I was standing on) that bent her in half.

MOVI0000 (3 min 46 sec)

MOVI0002 (3 min 15 sec)

MOVI0003 (1 min 16 sec)

MOVI0004 (7 min 34 sec)

MOVI0005 (3 min 33 sec)


Just got my counter rotating props yesterday, fixed the unexpected "hinge", and ready to take her up again this weekend. As soon as I crash her... ehem, I mean, unexpectedly land her again, I think I'm going to rebuild as a 30" WS like my most my other park flyers with a single tried and true 6x4 on a 2200 kv. If she actually survives another few weeks, I might re-configure to a side by side motor set-up and experiment with 2x8"@1400kv vs 2x6"@2200 kv and see which one gives me the best flight experience. I know side by side setups are more efficient than in-line setups.

I might even throw on a couple 64mm EDF's I have lying around to see what happens.
Last edited by elmagnificado; Mar 03, 2018 at 01:14 AM.
Mar 03, 2018, 03:22 PM
I Look, Listen, and Learn
Timbo383's Avatar
When flying inverted up is down and down is up.
Did the ground effects pull it down when you were low or did you panic and forgot you were still inverted? Either way it looks good....in the air, without the hinged fuse....


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