Author Topic: RC F-117A Stealth build  (Read 13781 times)

Offline Krown Kustoms

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RC F-117A Stealth build
« on: November 03, 2009, 09:07:02 PM »
I started this build before I joined this forum, but I will show you what I have as of now.
I found a Stealth video online somewhere and thats all it took.
I built the one in my avitar from a Mt Dew box just to see how dificult it was to build.
The build took a few hours, so I decided to make a bigger one.
This one is a test model (25x20), if it flies good I am going to make a big one (roughly 36x40)
I am using a brushless outrunner 3800kv pusher prop setup, 11.1 Lipo battery, DX6i 2.4 Ghz transmitter, karbonite gear digital servos, hobby foam fuselage, crappy epoxy glue that I will never use again.
I did a test on the motor, THIS THING SCREAMS.
I fear the prop detinating due to high RPM's.
Here are a few pics
-B-
-B-

Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #1 on: November 03, 2009, 09:10:44 PM »
Here are the pics just before the bench test.
I had a good bit of weight sitting on it to hold it still and it still pushed at 1/3 throttle.:)
-B-
-B-

Offline Bernd

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Re: RC F-117A Stealth build
« Reply #2 on: November 03, 2009, 09:35:25 PM »
That's pretty neat there B. Can't wait to see the finished product.

From what I see your using an electric motor for propulsion, right?

Bernd
You can't fix "STUPID".

Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #3 on: November 04, 2009, 08:40:47 AM »
Yes, this one is powered by a 3800kv brushless motor.
The bigger one will be powered by two electric ducted fans (electric jet engines more or less)
-B-

Ready for a test flight, I might get one in today if the temp gets above freezing.
-B-

Offline Bernd

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Re: RC F-117A Stealth build
« Reply #4 on: November 04, 2009, 10:58:42 AM »
B,

That don't look like it would be easy to fly. Looks like you need to pay attention to what your doing and it looks and sounds like it would go quite fast.

Bernd
You can't fix "STUPID".

Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #5 on: November 04, 2009, 01:05:04 PM »
Yeah...
I think it will end in disaster, I have never flown anything like this. (I think a bigger one will be more stable) I think speed is what keeps this one in the air.
I tried to build it as fast as I could, I didnt take in account how fast it will be and maybe should have taken more time with the rigidity of it.
We will see, I had to paint it due to the sun. I dont think white on top and bottom on a bright day will work out.
I painted the top black and the bottom red.
pics in a min, paint is drying.
-B-
-B-

Offline sbwhart

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Re: RC F-117A Stealth build
« Reply #6 on: November 04, 2009, 02:11:01 PM »
Yeah...
I think it will end in disaster, I have never flown anything like this. (I think a bigger one will be more stable) I think speed is what keeps this one in the air.

-B-

Thats what I was thinking but disaster or success its a lovely model I was interested on how you set the flaps up to work.

Good luck with the maden flight

Stew
A little bit of clearance never got in the road
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Location:- Crewe Cheshire

Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #7 on: November 04, 2009, 03:44:01 PM »
The transmitter has an option called flaperons, it mixes the elevator and aeleron control together.
It took a minute to set up (the thing is smarter than I am) I had to reverse one servo and adjust the travel, because it made the flaps verticle at full turn and thats more or less a brake. :scratch: maybe I can utilize that feature :poke:
Two servos do the work of four.
It looks a lot better with paint (it covers the flaws). :D Its taking for ever to dry due to the cold. :doh:
-B-

The big one wont have clear tape on it, that is just a quick holder for the glue joints -did I mention the glue dosent work very well, I should have used my usual stuff- :bang:
-B-

Offline Bernd

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Re: RC F-117A Stealth build
« Reply #8 on: November 04, 2009, 07:46:17 PM »
Looks real interesting B.

It is rather small when comparing it to the sofa cushion. With those colors it shouldn't be an trouble telling if your flying right side up or not. Be interesting to see a video of it fly, but I guess you'll have your hands full just trying to control it.

Didn't know it could get below freezing down your way.  :)

Bernd
You can't fix "STUPID".

Offline dsquire

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Re: RC F-117A Stealth build
« Reply #9 on: November 04, 2009, 11:58:00 PM »
Krown Kustoms

Looks pretty good. Nice contrasting colours to help with the orientation. I'll be watching for flight reports.  :D :D

Cheers  :beer:

Don
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and your better best

Russel

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Re: RC F-117A Stealth build
« Reply #10 on: November 05, 2009, 01:13:34 AM »
In one of the photos it looks like a spectrum AR6100E receiver, are you using a DX7 transmitter?

Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #11 on: November 05, 2009, 09:26:57 AM »
Bernd, the size is about 25" long, and we get plenty of cold here, just not the snow.
It is 34deg this morning.

Dsquire, I almost had a flight yesterday, but realized just before that my left right orientation is backwards -dont need that-, also with it getting late the wind picked up as the sun was going down. I added wheels for a rolling take off due to the akward way to throw it. I dont want to get bit by the prop.

Russel, Thats the one, I am using a DX6i. I borrowed the electronics from one of my helicopters (Blade 400)
-B-
-B-

Offline Bernd

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Re: RC F-117A Stealth build
« Reply #12 on: November 05, 2009, 09:44:18 AM »
-B-

Good luck with the maiden voyage.

25" that's not to bad. I thought is was shorter. Still I bet it'll be a bear to fly.

Again good luck.

Bernd
You can't fix "STUPID".

Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #13 on: November 05, 2009, 07:31:02 PM »
Well....

I tried a ground take off and no luck. (very fast on the ground)
I have adjusted the landing gear to be nose up, and will try again tomorow.
If all else fails I have a two story deck and can easily throw it from there for a test flight. (I dont really want to)
I dont have a lot of room so it will be just a stability flight with little turns. (trees)
I have read a lot of bad reviews of the F-117A due to stability so I might have to make this one a wall hanger if it dosent impress me. No reason to build a larger one if this one flies like a brick.
I wont scratch the whole idea, just for now. I would rather spend time on finishing the things I have left to work on this one.
until tomorow...
-B-
-B-

bogstandard

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Re: RC F-117A Stealth build
« Reply #14 on: November 06, 2009, 03:44:52 AM »
B,

I love your attitude.

If it works, great, if it doesn't, shrug your shoulders and try something else.

Sometimes we should all do that, instead of carrying on trying to fix a lost cause.

Admirable.


Bogs

Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #15 on: November 06, 2009, 10:50:21 AM »
Thanks Bogs

Well It wasnt a total disaster, this project isnt going to be grounded yet.
I wish I had video of the test flight it was great.
I set the trim with a lot of elevator because I was afraid it would nose in, when I launched it (off the deck) I used full elevator not thinking the trim adjustment.
It immediatly did a loop and then rolled left (battery pack on the left side) I didnt think the pack was too off center but I guess it was.
The thing flies like a dart, by this time it was probably going 40 mph and getting near the trees, so I cut the throttle and it handeled like a boat after you kill the throttle.
It nosed down hard and did a front flip and landed on its top (I have been told it dosent do well without throttle) I guess it acts that way due to not really having lift, more like floating on oncoming air.
I am fixing the broke pieces (not too much damage) centering the battery and adding more nose weight to prevent immediate lift on take off.
I guess we will see later.
-B-
-B-

Offline John Rudd

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Re: RC F-117A Stealth build
« Reply #16 on: November 06, 2009, 10:56:41 AM »

I am  centering the battery and adding more nose weight to prevent immediate lift on take off.

-B-

Rather than adding more weight, move the battery forward....and Delta wing style models( like yours) need a little reflex (Up elevon) to assist them getting away...Depending on your transmitter you program this in and switch it out once airorne

Seems like you had full uptrim on elevator when you launched it hence the loop...again Reflex...add about 1/8th inch from Neutral

I fly R/C planes too, so if I can help......
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Offline tinkerer

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Re: RC F-117A Stealth build
« Reply #17 on: November 06, 2009, 11:49:22 AM »
If you can determine the mean chord of the wing, it is an easy task to adjust the cg for stable flight. The cg should be about 25% of the mean chord. It will (should) be forward of the main gear and aft of the wing leading edge at the fuselage.
Tink

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Prov 13:19

Offline sbwhart

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Re: RC F-117A Stealth build
« Reply #18 on: November 06, 2009, 12:18:45 PM »
Hi Krown

No advice from me just congratulation on getting a flyer well done  :clap: :clap: :clap: I can see you breaking the sound barrier.

Have fun and thanks for sharing

Stew
A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline John Rudd

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Re: RC F-117A Stealth build
« Reply #19 on: November 06, 2009, 12:19:30 PM »
To calc the MAC is fairly easy...

Measure tip and the root chord.

Now draw the following lines on a large sheet of paper...

At the root of the wing, draw a line parallel to the centreline of the fuzz extending forward from the leading edge and rearward from the trailing edge.  These lines should be the length of the tip chord.

Do the same thing at the tip but draw the lines the length of the root chord.

Connect the ends of the lines so that they create an "X" over the wing panel.  Where the two lines intersect is the spanwise location of the Mean Aerodynamic Chord.

My C-o-C sketch may help.....



http://i754.photobucket.com/albums/xx182/Chippiejnr/mac.gif

« Last Edit: November 06, 2009, 12:54:42 PM by John Rudd »
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Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #20 on: November 06, 2009, 12:50:35 PM »
Thanks everyone for the interest and the help

I moved the batt forward and center for starters, angeled the rudders??? outward hoping for a little more stability.
I have a some sketch plans that I have been referencing and they have the CG located on them.

John,
I do have a channel for flaps that I can use for the elevons, I trimmed it in the first time because I thought it would need the elevator pitched up to sustain flight.
I cant make out your drawing but I think I see what you are refering to.

By the way, I have been calling the elevons "flaperons" for some reason not sure where I acquired the term, but I wanted to clear that up.

Tink,
I am new to aerodynamics, and have to google all of the terms you guys are using, I have been going by trial and error -mostly error-
I am looking up mean and root chord now.

Stew,
Thanks for the positive reinforcement.
Im not sure I would call it a flyer yet but well on its way.

-B-

-B-

Offline John Rudd

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Re: RC F-117A Stealth build
« Reply #21 on: November 06, 2009, 12:55:46 PM »
KK,

I posted the link for the picture....I'm still on a learning curve for posting from 3rd part sites...

Hope it helps.
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Offline Krown Kustoms

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Re: RC F-117A Stealth build
« Reply #22 on: November 06, 2009, 12:59:38 PM »
I got the link but I cant resize the pic on the link, It is the same size as your post.
-B-
-B-

Offline John Rudd

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Re: RC F-117A Stealth build
« Reply #23 on: November 06, 2009, 01:07:41 PM »
KK,

I sent the pic via email to you.......
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Offline tinkerer

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Re: RC F-117A Stealth build
« Reply #24 on: November 06, 2009, 01:37:19 PM »
I would attempt to explain, but I think learning the aerodynamics is important if you will be doing a lot of flying. It will give you some insight to why some things are happening. There are a lot of variables in aircraft design, each affecting another. Good luck with the adjustments and next flight. Get some video for us.
Tink

The desire accomplished is sweet to the soul.
Prov 13:19