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Old Jun 05, 2005, 10:13 AM
Supersonic hover
Esprit440's Avatar
Michigan, United States
Joined Sep 2003
1,043 Posts
Northrop/McDonnell Douglas YF-23 Black Widow II

This model was built as a fanfold test project two years ago, crashed a lot on test flights, and retired without flying more than short hops in my back yard.

It sat in the back of my workshop since then, and every time I saw it I had a nagging feeling that I should resurrect it. Recently I was reviewing my reference files for the real YF-23s, and was struck by how badly the two prototypes has deteriorated - a sad end for such beautiful jets.

So yesterday I went into action, and rebuilt my tired old test model. Out came the weak IPS-A drive, and in went a 17T LensRC motor. The model had been crashed, repaired, and cut up to get the gear out; I had to slice it open again to get the new gear in.

Gave it a quick paint job and some "flyby" graphics; now it was looking well used but presentable. Much better! It felt good to rebuild this one.

First flights today were a little disappointing. The model had plenty of power but control response was squirrelly - ailerons are needed, not just quirky V-tails. Luckily it shook off a couple more hard landings without complaint.

More to come, some day...

-Matt
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Old Jun 05, 2005, 10:16 AM
Supersonic hover
Esprit440's Avatar
Michigan, United States
Joined Sep 2003
1,043 Posts
Flying once again; I really enjoy seeing this shape in the air.
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Old Jun 05, 2005, 02:29 PM
My cat up close
bipeflyer's Avatar
England
Joined Feb 2001
4,021 Posts
Looks nice Matt- I think you should persevere with it, and get the flying anomalies wrinkled out.Certainly is different!

Matt
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Old Jun 05, 2005, 07:19 PM
2014 EDF JET JAM We be Jamming
Kevin Cox's Avatar
St. Louis Intl, Missouri, United States
Joined Jan 1997
6,806 Posts
Awesome!

I'm planning a similar approach but with a different powerplant .

Great work Matt
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Old Jun 05, 2005, 07:21 PM
Go Sabres!
savall21's Avatar
Laurel, MD
Joined Aug 2004
810 Posts
That's a beautiful model. To beautiful not to fly. Keep it up.
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Latest blog entry: Aerial Video of Cincinnati Ohio
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Old Jun 05, 2005, 09:44 PM
Supersonic hover
Esprit440's Avatar
Michigan, United States
Joined Sep 2003
1,043 Posts
Kevin, I'm looking forward to seeing yours! If you're thinking of a pusher, I would recommend a shaft drive system for anything larger than a cd-rom motor. The YF-23 builds tailheavy and as you scale it up (mine is just under 21" ws) it will get worse.

I'm traveling on business for a week so the aileron modification will have to wait. This sucker is gonna fly well, one of these days!

-Matt
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Old Jun 06, 2005, 08:04 PM
2014 EDF JET JAM We be Jamming
Kevin Cox's Avatar
St. Louis Intl, Missouri, United States
Joined Jan 1997
6,806 Posts
Ahh...from the archives

It was a big one, long before brushless and Lipos. It was shaft driven by an Astro 05FAI
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Old Jun 11, 2005, 06:41 PM
Registered User
RCParkflyer's Avatar
Racine, WI AMA# 809291
Joined Nov 2003
5,856 Posts
signing on
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Old Jun 12, 2005, 01:00 AM
Watts your motivation
roccobro's Avatar
San Bernardino, CA
Joined Aug 2003
6,512 Posts
Signing on also... Beautiful.

Justin
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Old Jun 19, 2005, 08:48 AM
Supersonic hover
Esprit440's Avatar
Michigan, United States
Joined Sep 2003
1,043 Posts
I added ailerons this week and took it out for some test flying this morning.

First flight was slightly better than the previous attempts, but still not very controllable and noticeably tailheavy. Landed fast and broke a prop. There was a seagull circling around overhead making "HAW HAW HAW" sounds, I kid you not.

Put on a new prop, then put it back on the facing the right way, and added some weight to the nose. Also had to fix the bell on my cd-rom motor which had been knocked loose again.

Next flight was slightly nose heavy at launch and lasted about a minute. This model flies strangely - very twitchy in pitch and eventually settling into a 30 degree nose high attitude and spiraling around slowly. It's very stable like this, and will fly hands off for a long time. When I fed in some down elevator or aileron, it snapped out of the spiral viciously and I had my hands full recovering.

There are probably several things causing problems:

- the unusual delta wing & v-tail configuration
- uncertain v-tail alignment due to builder error
- oversized & flimsy elevator control surfaces
- undersized ailerons
- incorrect thrust line
- incorrect CG

This poor model has had a rough life so I think I will retire it and build a new version some day.

-Matt
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Old Jul 29, 2006, 09:37 AM
Registered User
Germany, Gaggenau
Joined Jun 2005
206 Posts
Quote:
Originally Posted by Esprit440

-This poor model has had a rough life so I think I will retire it and build a new version some day.

-Matt
hi Matt!
did you start building a new one?
Moritz
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Old Jul 29, 2006, 07:33 PM
Supersonic hover
Esprit440's Avatar
Michigan, United States
Joined Sep 2003
1,043 Posts
Hi Moritz,

No I haven't built another one yet. Some day! Right now I am finishing up the design of a little thrust-vectoring jet for EDF-40.

How about your YF-23?

-Matt
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Old Jul 31, 2006, 12:47 AM
Registered User
Germany, Gaggenau
Joined Jun 2005
206 Posts
Hi Matt,
i did a reinforcement with 25grams GFK layer on both sides on my jet:
http://www.rcgroups.com/forums/showt...10#post5827181
How were the flight characteristics of your YF-23?
Did it you fast? Was it very difficult to control?...
Moritz
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