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Old Jul 03, 2001, 04:32 PM
My cat up close
bipeflyer's Avatar
England
Joined Feb 2001
4,021 Posts
F-14 Tomcat EDF,pictures and questions

Hi,
Firstly,thanks to everyone who helped out with my 'Velkom' query.
I have been up in my attic,admiring my unflown Tomcat,I designed it for tractor glow power,but have gone cold on that idea now,the model is 32" max. sweep,57" min. sweep.My new WeMoTec mini fans are beckoning me to fit them,trouble is,I did not fit any ducting during the build.However,the wing can be removed on it's support box as one unit,this allows access to the sweep mechanism for maintenance.
I need to retrofit ducting,anyone tried this before,and how did it go?
I've decided,by the way,to go with Plettenburg motors to go with my fans. http://www.geocities.com/grumman_uk/web-17.html
Cheers,
Matt.
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Old Jul 03, 2001, 05:36 PM
Registered User
Mesa, AZ
Joined Jun 2001
36 Posts
All I have to say is you have a really nice looking jet. I wouldn't want to know how much time would be lost if you were to crash that beautiful F-14.
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Old Jul 03, 2001, 05:52 PM
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Foxtrot's Avatar
Kodiak AK USA
Joined Jun 2000
609 Posts
Holly Cow!! Nice. Are the plans available yet? I can't help with the ducting problem. But I'm sure someone around here can. Are the plans available yet? Oh wait I already asked that.
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Old Jul 04, 2001, 12:05 AM
Speed Demon
GregG's Avatar
Antioch,CA,USA
Joined Dec 1999
12,296 Posts
Matt, outstanding job on the split tail cat! It would be a shame to mess it up with a prop on the front and it's cylinder and pipe hanging out. Best of luck getting it working with the twin EDF's.! <img src=http://www.flightlines.com/forum/icons/icon14.gif>
I may even go for a set of those plans when you finish them!
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Old Jul 04, 2001, 01:50 AM
Registered User
San Diego, CA
Joined Feb 2001
283 Posts
Matt-

OOOHHWHEE! The Professor has a soft spot in his heart (and head too) for that 'cat. Swing wings too huh? Wow, what a fantastic accomplishment ! Please tell us more about the construction methods used in this cutie and how much it will weigh, wing area, wing loading, power loading (watts-in/#). I too am interested in plans building. Can offer something fairly unique in return : (unclassified) engineering details on the real thing! US Naval Aviation is my work thing.

As for the ducts, suggest chemical milled titanium for the inlet... or fiberglassed, packing tape covered blue foam. My duct suggestion and good idea about the packing tape by Brian Chan (and others)are contained in another thread on this page titled "YELLOW AIRFRAFT F-4" or something close to that. I'm afraid I have not yet figured our how to copy a link. My suggestions on power and wing loading are germane also.

Please Keep Us All Posted,

Steve Manganelli, AKA Prof. Maneuver
P.S. I am the designer/builder of the 3 MF-480 powered XB-70 Valkyrie
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Old Jul 04, 2001, 08:57 AM
Flying Welder Pilot
Plane Crazy's Avatar
Reno, Nevada
Joined Jan 2001
1,137 Posts
bipeflyer- Very nice cat!!!, you have quite a collection of nice planes.

So much of the ducting issues depend on the internal structure and formers under the wing. There are some good duct discusions on this thread http://www.ezonemag.com/disc/Forum6/HTML/001832.html also see http://www.ezonemag.com/disc/Forum6/HTML/001779.html

How much does the plane weigh currently? Probably the hardest part will be modifying the formers for the ductwork, and getting the airframe light enough to carry batterys. Since you have plans in the works it might be easier to rebuild the fuse with the intended components designed in. It would be sooo hard to tear up such a nice looking plane.

It is nice to see more people thinking of larger EDF plane projects.

Gordon
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Old Jul 04, 2001, 10:50 AM
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Kevin Murray's Avatar
USA, NC, Greenville
Joined Dec 1999
9,271 Posts
Matt, Great looking F-14. Put me on your list for a kit, and the plans also.

As for the ducting. Try searching "lost foam". The lost foam method is to carve or sand into foam the shape you want the final piece to be. Then cover it with FG or CF, when the resin has cured, you melt the foam out of the FG or CF tube. Acetone is uset to melt the foam.

Mabey Kevin Cox will post a reply here. He also has a scratch built EDF F-14.
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Old Jul 04, 2001, 03:49 PM
My cat up close
bipeflyer's Avatar
England
Joined Feb 2001
4,021 Posts
Well,what a response!
Glad to know there is much interest in the '14 as I have!
That model was very hard work to design-it made my brain ache at times,but got there in the end,I have no CAD skills,so the hard way was the only way.
I definitely will not fly it under glow power,that would indeed be deemed as sacrilege,so on with the ducting....
There is a lot of information to wade through,but what the hell,if it's too difficult,or likely to inflict too much damage during the conversion,I will build another one,EDF it,fly it,and sell plans for it!!
Yes the swing wing is selectable in flight,(god willing)if anyone is interested in getting plans for this model eventually,e-mail me,and I will contact you when they are ready (after testing only).
If anyone would like to see Dirk Juras' electric F-14 in flight,follow this link to download the mpeg.video. http://aeneas.ps.uci.edu/edf/mirrors/f-14_juras.mpeg
Cheers,Matt(SadlyThere are no plans availabe for the German Tomcat)
Incidentally,my models'estimated AUW with a two stroke .32,plus radio was 4.5-5lbs.

[This message has been edited by bipeflyer (edited 07-04-2001).]

[This message has been edited by bipeflyer (edited 07-04-2001).]
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Old Jul 10, 2001, 02:47 PM
Dude, where's My Plane?
JasonJ's Avatar
Green Lane PA USA
Joined Mar 2001
2,167 Posts
Nice jet, cool Mpeg! Im in for plans too!
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Old Jul 10, 2001, 03:30 PM
Lithium Member
Herb's Avatar
Irvine, Calif USA
Joined Feb 1999
12,127 Posts

Issues such as ducting, edf powering, fan construction etc - as well as some F14 details - are discussed by the way in nice and accurate thorough detail in Dirk Juras' excellent book, Das Electro-Impeller Buch, FMT Verlag.

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Old Jul 11, 2001, 11:45 AM
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Alan W's Avatar
NY
Joined May 2000
2,161 Posts
Did you predict or plan for any CG change in the sweep process ???

Very nice looking plane !!

Alan W
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Old Jul 14, 2001, 11:28 AM
Registered User
sydney,NSW,Australia
Joined Jul 2001
4 Posts
Correct me if i'm wrong bipeflyer.
if the plane is balanced for good "stability vs manueverabilty" in forward swept flight first then when the wing is swept back the neutral pt will be even further back from the CG (essentially the cg is unchanged, except for the mass of the wing).
More longitudinal stability would then be the result which means less control autority but this is partially offset by the higher speed resulting in swept flight anyway so this is ok. You could use exponential or high rates to solve this.
The only thing to watch for then is to feed in a little bit of up elevator at higher angles of sweep (like chris gold said about his tornado) or mix it in.

[This message has been edited by yechuah (edited 07-14-2001).]
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Old Jul 14, 2001, 01:58 PM
My cat up close
bipeflyer's Avatar
England
Joined Feb 2001
4,021 Posts
Hi,thanks for that input Yechua,I have already got some advice re. balance in flight,another guy who flys i.c. ducted fans has a DCU F-14,he advises,as you do,to 'give a couple of clicks'of up trim in minimum sweep conditions.Obviosly,manoeverabilty in this condition will be affected,I guess the tuning radius will be affected,so am prepared!
Thanks all the same!
As for those who have asked for plans,I have added you to my list,and will contact you again nearer the time-I will have to build another F-14 as a test bed for the EDF version.
I have gleaned a lot of information from the German 'Jetmag' magazine,and will be incorporating information from this scource in my next model-no point in re-inventing the wheel!
Many thanks to you all for your interest,by the way,I haven't worked out a price for the EDF version yet,also I will post details of developments on this forum as soon as they happen-watch this space!
Please feel free to send me an e-mail if you wish to discuss things in more detail.
Matt.
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Old Jul 14, 2001, 06:10 PM
It wasn't me...
DanSavage's Avatar
Trabuco Canyon, CA
Joined Nov 2000
4,547 Posts
Quote:
Originally posted by bipeflyer:
...I have already got some advice re. balance in flight,another guy who flys i.c. ducted fans has a DCU F-14,he advises,as you do,to 'give a couple of clicks'of up trim in minimum sweep conditions.
Hi Matt,

I finally found the info I was looking for on variable geometry wing designs.

It's at: http://www.hq.nasa.gov/office/pao/Hi...468/ch10-4.htm

Basically, the full-size aviation community went through this exercise with the Bell X-5. They found that when the wing pivot points are on or near the aircraft centerline, then an expected CG shift occurs. The solution for the X-5 was to incorporate a translation mechanism that "slid" both wings forward as they swept rearward.

Research done at the NASA Langley Research Center showed that the CG shift could be minimized by moving the pivot point outboard, away from the centerline and incorporating a highly swept "cuff" that supports the wing and fairs it to the fuselage.

These design features were used on the F-111, F-14, B-1, RAF Tornado and MiG 23/27.

This basically agrees with what your friend who flys the DCU F-14 said about trim changes.

Dan
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