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Old Jan 20, 2012, 10:25 PM
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swimmer's Avatar
United States, KS, Derby
Joined Mar 2008
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Quote:
Originally Posted by wolfewinde View Post
Well - I can't see sanding down the gorgeous paint job on the top - maybe could sand the bottom - can't see what the paint is there from the pics.

I have to say that in the past I have put hours of effort into a model that would not fly well for one reason or another and it breaks your heart.

I would try things in this order....

Take off the plastic cowl, lose the nose weights, and move the battery under the motor mount stick so it is under the cowl. I would try a 1300 mah 3s battery

Then I would cut 3 vent holes - as large as I could get away with - on the bottom of the fuse between the trailing edge of the main wing and the horizontal stabilzer.

Then recheck the balance and the overall weight.

I would be trying to get the weight back under 25 oz at least.

At this point you haven't wrecked the existing paint job and you have some idea how much you can reduce the weight.

If that was not enough, I would cut the nose and motor mount stick off just in front of the existing firewall. Then I would extend the fuse about 1/2 inch to 1 inch, put in a plywood firewall, and mount a 450 to the new firewall. Then re-attach the nose you cut off to the new fuse extension. Secure that with carbon fiber rods glued under the nose section and into the fuse You could lightly glass over the fuse extension and paint it to match the existing paint job. And then you could put the battery in by taking off the cowl on the underside.

I would bet that you could get the weight down significantly that way, not wreck the work already done on the finish of the plane. and end up with a plane that will fly .

It's a bit more work, but at least you are not undoing too much of the work you have already done.

My goal would be to achieve less over all weight and get her to balance by positioning a lot less weight a lot further forward. If Icould get her under 25 oz I would probably try to fly her. If not, then I would probably just display her as swimmer suggested.

Wolfe
Excellent suggestions.
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Old Jan 20, 2012, 10:34 PM
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Taiwan, 北市
Joined Dec 2010
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Wolfe,

I'd expect to get 20.5 oz or even 20 oz. on the new EPO Spitfire if it's with 400 size 1000 KV motor + 3S
1300mAh lipo + 20A ESC, and with the thinnest paints.

Chen
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Old Jan 21, 2012, 03:55 AM
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United Kingdom, Cnwll
Joined Apr 2010
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thanks for all of your help and suggestions folks! I've used the same motor in the past in my Lanyu EPO Corsair, and the AUW with the same battery was 25oz and that worked fine. I'd like, if possible, not to get much more speed than this motor gives - it's a small Spit and I don't really want it going at scale speeds in excess of Mach 1!

Paints are a couple of coats of Xtracrylix top and bottom.

In terms of weight, there's about 5oz of lead in the nose just to get near the CG!!!! So If I can lose that, I'm happy.

I might try and get a smaller 3 cell 1300mah battery right up under the motor, it's going to be a tight fit though...

will try with the vent holes as well.

thanks again for all of your help, will keep you updated!
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Old Jan 21, 2012, 08:12 AM
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United States, NJ, Frenchtown
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Lead is a Toxic substance in a plane.

Never put in lead. Dead weight does nothing to help the plane fly.

Add BIGGER motor with a prop that has bigger pitches.......mandatory for heavy planes. It MUST fly faster. + 35 mph. BIGGER bateries & ESC.

Glass coatings DO NOT improve anything to do with flying. Ever. It DOES raise the crash speeds & impact forces.

I do a lite spackle of all imperfections. COMPLETE sanding with 100 grit sandpaper. That allows the foam to take paint very evenly. I dilute the H D Latex paint by 25 %. 1st coat is deliberatly light & streaky. DO NOT try to make it nice. It is used as a primer. Second coat is perfect. I use cheap foam brushes. Looks great & IS LIGHT. DONE.

Rich
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Old Jan 21, 2012, 09:01 AM
always something to learn...
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Tacoma, WA
Joined Jan 2011
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Ok. I looked at the gorilla glue I had used on the C-47, and it was indeed their gorilla *super* glue! It is really too bad I discovered they had different types only after I wrecked yet another portion of this old, never flown aircraft. I have half-heartedly started repairing it, and I shall see how it goes, but if it ends up too heavy, I shall probably scrap it, and put the componants in a fresh airframe. On a higher note, the AT-6 foamy made by HK showed up yesterday, even with all the snow/ice outside. It is now ready to fly, and pending better conditions, it will soon. Now if the Vampire just shows up...-----Metalguy
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Old Jan 21, 2012, 09:37 AM
My Co-Pilots Rock!!
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United States, FL, Clearwater
Joined May 2011
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Lord - good luck on the fix - hope it works - sounds like it might

Metal - Bummer on the Gorilla Glue - I did not know they made a super glue either - easy mistake to make - so many ways to screw up without realizing it LOL. Good luck on the AT-6 maiden.

Got in six flights this morning before the wind got too bad (over 10 mph) - Formosa, Gemini & Edge were on duty today. That Formosa 1 does very well in some wind. Running 175 watts on her.

A friend came over that I use to fly with a lot He flys mostly at the Club now, so not used to the trees anymore - lots of trees surrounding the City Field. One of them ate his 48" 3dhs edge - really a bummer - ripped the wing right out of the fuse. 4 planes went into the trees this morning - thankfully, none of mine. Trees were hungry today.

Chen - thanks for the Spit info - I really appreciate you monitoring this thread and helping us out

Cyclops - good tips, thanks

Wolfe
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Old Jan 21, 2012, 09:44 AM
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Lordmureth,

I will echo wolfe's statement....good luck.

Thanks, Chen. I'll have to check out the EPO models.

Hey, wolfe. Glad you could fly this morning. Here in Kansas it is 14 degrees.

Allan
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Old Jan 21, 2012, 10:03 AM
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United States, NJ, Frenchtown
Joined Mar 2003
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metal guy

I did the melting foam many time.

My cure is to cut out the bad stuff completly with cut lines as straight as as you can. Like a square or rectangle in shape. Glue a over sized piece in. Sand, paint, reslot do what else is needed. First piece I did 2X. After that I am fast. I do the same on crashed areas.
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Old Jan 21, 2012, 10:13 AM
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United States, NJ, Frenchtown
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Happiness is

A dark olive drab Transport. Now I am think Spectre gun ship. It has that Nam color look.
H D mixed a gallon for me..............Lots of Nam planes are in the paint shop waiting for 2 light recolors.

Still no Sullivan Flex cables for R & E.
Replacing the H D thermostat solid wire with BP Hobbies Futaba 22 gauge servo wire. Should be easier with much more flexiability. At 5 amps each, no problems. 220 wats in a Transport will do the job.

Rich
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Old Jan 21, 2012, 11:37 AM
always something to learn...
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Tacoma, WA
Joined Jan 2011
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Wolfe, bummer about your friend's plane! Haven't had a plane get eaten by a tree in some time, not since my Dad flew my old pico cub into one, up high...
Cyclops, I am pretty new to the foam repair with anything but 5 min epoxy, or titebond, so this melty thing really bums me out. Repairs are on the way for now.
It all started when I wanted to paint...maybe its a sign. Oh well! I have mucho sanding and repairs to do on this one. Good thing I have others to fly in the mean time!------Metalguy
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Old Jan 21, 2012, 01:06 PM
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United Kingdom, Cnwll
Joined Apr 2010
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bugger... tried to get my 1300mah to fit under the motor, but since I'm using the lower mounting point there's no waaaaaaaaaaaay I can find room for it there, unless I try and cut a piece out of the cowl and form a very un-Mark 1 like vokes filter over it lol!

Measured the weight with the battery strapped under the nose, and no weights, and it's spot on 25 ounces which I reckon would work - but the CG is still too far back. Have cut one hole in the rear fuse so far, but I'm starting to think the larger motor might be the way I have to go...
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Old Jan 21, 2012, 01:49 PM
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Plane gets heavy ?

MORE cubic inches in the engine always works on heavier planes. It is mandatory.

EVEN IF the plane is small in wing area. Cut back on battery flight time.

I WILL ALWAYS accept short times, if it is at least 7 minutes......I use a 15 minute mechanical electrical switch. Big, no batteries & noisey when it goes off.

" Stay out of the landing area !! The Lord Mureth is coming. Very HOT as usual. "

Get some respect from the commoners. Here here.


Rich
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Old Jan 21, 2012, 01:58 PM
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United States, NJ, Frenchtown
Joined Mar 2003
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My GWS Spitfire has 2 batteries in the chin blister & 2 in the upper area in the nose. They are heavy 1100 mah A123 cells LIFEPO4. Good COG balance. They are held in with Silicone rubber. Takes some time to get the battery jumpers right the first time. No shorts are allowed.
It is running a 3500 Kv motor in about a 6 : 1 400 sized gearbox. VERY strong climb straight up. About a APC 8 x 8 ? Old plane hauls.
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Old Jan 21, 2012, 02:29 PM
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Had to dig around for rough computer sheet for performance.

Rich
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Old Jan 21, 2012, 03:53 PM
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Joining the fun!
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