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Funterceptor

Funterceptor

The plan build article by Chris Reid - 20/7/09

David Ashby - Moderator08/05/2008 11:38:00
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The free plan from the June issue of RCM&E didn't have the C of G printed. Sorry folks, this should be - Forward C of G - on the mainspar centreline Rearward - 11mm back from the mainspar centreline
Ken Latam02/07/2008 01:24:00
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102 forum posts

Thanks David.

Going with an OS FP .10  in mine,with a flat wing and a steering tail wheel.

Ken 

David Ashby - Moderator03/07/2008 16:55:00
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Should go well Ken. Pop on some piccies when you can .. David.
Muhammad Ul-Haque16/09/2008 08:13:00
1 forum posts

Hey David

This plane is my first scratch build and it didnt go according to plan. For starters mine is abit on the heavier side, all up weight is 702 grams. I realize that this due to the fact that i used monokote instead of solarfilm.

Another area of concern is that my Cof G is 20mm behind the main spar(after adding 70 grams of ballast weight) was wondering if u see major problems occuring during flight with this setup?

Muhammad 

Mike Robey19/09/2008 04:10:00
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54 forum posts
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Hi David,

I have a similar situation to Muhammad.  Also my first build.  My all

up weight before balancing was 550gm (a little over yours) but to put the CG

a few mm behind the main spar, I have had to add 150gm of lead!! I glued

the lead to the inside of the cowling to put it as far forward as i could.

The result is my finished plane is a tad over 750gms which puts it

just under 50% too heavy.   I am now wondering what effect this

will have when I get it into the air.  I am guessing a higher wing loading

means a higher stall speed.  The question is, how much higher?

Any feedback or suggestions you might have would be greatly

appreciated.

Chris Reid19/09/2008 10:42:00
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224 forum posts
95 photos

Hi Michael,

 Sorry to hear that you, and others are having problems with a rearward CG on Funterceptor.  Maybe your tail end has come out a bit heavy, or perhaps you are using a Lipo battery.  My Funterceptor was designed around 7 cell 1050mAh KAN packs which are heavier.  At the start of the design stage, I hang all the bits on a rod and find out where thay balance.  This marks the CG and hence the wing design location as I put the main spars on the CG. 

The CG range I have suggested is very safe.  Thus you can let your CG go to 33% of the wing chord back from the leading edge.  This amounts to 2.7inches (11 mm  back from the rear edge of the spar).  Even here the model will be OK.  Aft of that it will start to get pitchy, but you could try it and see.

 Funterceptor is a light model, and yours is heavy.  It will fly faster, and probably land harder in consequence.  However, my light one is a real floater, so you shouldnt have too much of a problem.  Do your stall trials high up and see how it looks.  My Funcerceptor's stall is very benign, just a sort of mushing.

Try moving the CG a bit aft if you can do so  by removing some lead from the nose. Maybe you could change a lipo and lead for another battery, although that won't do much for all up weight.  If you are using mini servos at the rear you could maybe swop them for micro versions, that would help too.

Hope this helps,

Chris Reid

Mike Robey19/09/2008 13:33:00
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Hi Chris,

I am using a lipo battery.  I'll try her as she is and, as you say, check out the stall

speed up high. I am looking foward to seeing how she handles.  I have never built anything

like this before and i really enjoyed it (except for stretching the covering over the wingtips).

I'll let you know how it goes.

Mike Robey20/09/2008 01:40:00
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54 forum posts
15 photos

Hi Chris and Muhammad,

Just came back from the maiden flight of my overweight Funtercepter.  Chris, your observations

about the flight charactersitics with more weight were pretty spot on.  Yours must REALLY

float because mine came down reasonably slowly and settled nicely on landing.  With a tad

of throttle, she seemed happy to tool along 1 foot of the ground for ever.

 VERY NICE plane to fly, as you say stalls are a none event and she handles

gently.

By the way: I used two aileron servos in the wings and I didn't build the dihedral in.

I didn't want any self correction but I did want to take advantage of they symetrical

wing section.  I didn't try inverted flight today but will give it a go on the next flight.

Chris, thanks for a great design, enjoyed building and look forward to more flying.

 Muhammad, go ahead and fly, the extra weight will be fine and this is a really fun bird

to fly.

Chris Reid20/09/2008 12:41:00
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224 forum posts
95 photos

Hi Michael, 

I'm delighted that you are having success with your Funteceptor.  As a designer, it gives me a real buzz when a model works well for others too.  When I was first drawing the model up, I intended to have a wing without dihedral, hence the 36" stock design.  However, I thought better of it and put some dihedral in to help the novice pilot.  My model flies up to my aerobatic ability - once I'd tamed the ailerons a bit.

 All the best,

 Chris

Muhammad Ul-Haque 213/10/2008 20:43:00
1 forum posts

Hey Michael and Chris,

I flew mine a few days ago and boy was it a joy to handle. Very good gentle handling. Though I did manage to mess up the landing resulting in a broken motor mount and propeller. Very fortunate that , that was the extent of it.

Just fixed her up again with a slightly longer mount to correct the C of G and less ballast weight. Waiting for a good day to take her up again, hope to get her floating in the sky Chris.

Muhammad 

Chris Reid13/10/2008 22:06:00
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224 forum posts
95 photos

Hi all, 

I'm still having a lot of fun with my Funterceptor.  I get 10 minutes from the 7x1050mAh NiMH cells.  No problems with the flying, but I have had a wing tip and aileron chewed up by an ic model that ran into it on the ground.  It lives to fly again.

CR

Mike Robey27/10/2008 11:56:00
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54 forum posts
15 photos

Hi Fellow Funterceptor Flyers,

I just came back from test flying mine (Version 2). I tried a larger motor and some

Lipos which had a higher C rating. This setup generates about 135 watts

while drawing 14 amps. I will try a higher pitch prop because I want to get

that up to about 160 watts and around 17 amps. She'll loop from level

flight as it is but the extra power will allow bigger loops etc.

It really is a fun little plane to fly. Its Magpie breeding season down here

(Perth, Australia) and I had some fun with a rather aggressive magpie trying

to attack my plane. I discovered that Magpies just don't understand a half loop

so they are easy to escape.

I thought I'd attach some pictures of mine. I hope to have some flying shots soon.

Being Australian I went with WW2 RAAF markings (sort of).

/sites/3/images/member_albums/33947/FunterceptorBuild03.JPG


/sites/3/images/member_albums/33947/FunterceptorBuild01.JPG


/sites/3/images/member_albums/33947/FunterceptorBuild02.JPG


Chris Reid27/10/2008 15:16:00
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224 forum posts
95 photos

Hi Michael, 

bonzer mate.

 Chris

Ken Latam27/10/2008 19:48:00
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102 forum posts

Sharp looking,but who is flying it??? (hint hint-needs a pilot)

Ken

Mike Robey29/10/2008 07:27:00
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54 forum posts
15 photos

I agree it does need a pilot.  I wanted to go with a suitably sized

Snoopy but I can't find one.

Ken Latam29/10/2008 18:02:00
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102 forum posts

Seeing as december is approching quickly, how about a small "snow white BOOMER" ?

It would add to the OZ flaver.

Ken

John Walker15/12/2008 17:22:00
3 forum posts

hi all i am just starting my build and noticed no c of g,

and have found this forum very helpful.

i will let you know how i get on.

cheers all,

     johnboy.

Chris Reid15/12/2008 19:15:00
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224 forum posts
95 photos

Hi Johnboy,

 RCM&E left the CG position off my plan (see post 1).  Build  to get it on the main spar or slightly aft  of there.  I'm still having a lot of fun with my Funterceptor.  I hope you enjoy yours.

 Chris Reid

John Walker24/12/2008 21:28:00
3 forum posts

hi chris,

the build going well so far, have moved the rudder servo foward one inch.

i thought it might clash with the elevator servo, this will also help with keeping

the tail light.

have a good xmas

johnboy.

xxx.

Roy Bellord02/06/2009 22:34:15
13 forum posts
2 photos
Hi Chris,
just had maiden flight with my Funticeptor,flew really well,great fun . Cant wait to fly again.
    Roy.

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