Author Topic: Cox Spitfire Replica Build - Flight video (Read 23213 times)

goozgog · « **on:** October 31, 2014, 01:22:08 PM »

   First flight video May 16 2015

https://www.youtube.com/watch?v=qfOuNAUTh70&feature=youtu.be

I promised to report on my build of a balsa replica of
a Cox plastic Spitfire and this is it.
  It might be worthwhile to look at the previous post
that explains my motives.

http://stunthanger.com/smf/index.php/topic,31282.0.html

  I am very grateful to Larry Renger for his help.
His careful photography of an actual plastic Spitfire makes
this project possible.
Thanks again Larry!

Picture #1 below is of the version I had.
Insipid green gorgeousity!

  The first thing I needed to do, was open Larry's photos in
Adobe Illustrator and trace the outline. It sounds easy but
adjusting for the photographic parallax was tough. I know
the overall dimensions it should be and I adjusted to that.
   The beauty of any CAD program is that you can flip and
mirror image and average the mistakes. At least port and
starboard will be identical. When something wasn't clear from
the pictures, I referred back to the excellent 1941 M.A.N.
wylam-spitfire.
Google it. It's GREAT!

   Something I really enjoyed was studying the changes that
Cox had to make to a Spitfire to model it in plastic. The nose
is longer than a canon equipped Mk II , which I assume Cox
was trying to represent. The other bizarre thing is the position
of the bell crank and lead outs. I know bell cranks can be
anywhere but Cox has it way aft. I dunno.
I'm keeping the lead out where Cox had them but the bell
crank is going forward 3/4 inch. My childhood Spitfire flew like
cheddar cheese but it did have line tension.

   Picture #2 shows the "spread fingers" ribs that worked so
well in my Beaufighter. This is a very easy, accurate and fast
way to make tapered wings. I built the wing directly on the plans
that were taped to my flat table.
  I had to decide what foil to use since Cox used the under
camber that made sense of the plastic molded wing.
Since Mr. Mitchel used a 12% semi-elliptic foil I thought it
might be good enough.

The dihedral angle was also vague. I studied the pictures but
couldn't find a clue so I just went with the Wylam reference.
A real Spitfire has a flat center section out to the landing gear
but Cox went with just one "Joint". Since it will be hidden under
the wing root fairings and because it easier I went with the flat
section.

Picture #3 shows the completed wing with the lead outs and
dihedral. The wing took about two hours.

  Picture #4 shows the plug that I'm going to use to mold the
fuselage sides. I decided to use pine for this instead of blue foam
or balsa since I wanted it to be strong and hard enough to
wrap tight and wet.
  The picture shows the plug without the Spitfire's usual bulges
over the valve covers and without the wing root fairings.
I decided that carving the plug straight and symmetrical would
be easier without these details, which I added later.

  It's amazing how much I remember about the plane I had in 1968.
Building this reminds me of individual dings and scratches of my
original. I remember how the fuselage had to be split to remove
the engine and of the plastic firewall/mount. I can almost
taste it. ( Yuk!)
  Mine had a complete Queen Bee engine with a larger plain
aluminum tank and "brass" back plate, but I'll put a Black Widow
in this one. If I keep it light enough it might fly.

If anyone would like a PDF of the outline just ask.

  So that's it for now. I'll do another update soon.

Cheers!

Larry Renger · « **Reply #1 on:** October 31, 2014, 01:37:55 PM »

Looking good! Keep those photos coming.

mike londke · « **Reply #2 on:** October 31, 2014, 03:47:07 PM »

Very impressive.!

Bill Smith · « **Reply #3 on:** October 31, 2014, 05:15:31 PM »

Nice job so far.
I think you might be surprised how well it will fly

goozgog · « **Reply #4 on:** November 01, 2014, 06:36:12 AM »

It was a wet miserable Halloween here and I feel bad for the kids,
but it's prime building weather and my forced air furnace dried the
wet balsa beautifully.

  Well! this worked much better than I was expecting. I just soaked
1/16" balsa in hot water for 15 minutes then wrapped it very tight
with tensor bandages from the dollar store.
  My !@#$%^&*! cat decided that the wet cloth thing on the heat vent
was interesting and had a chew at it. @#$%^&*(!!! cats!, but as picture
#1 shows the balsa molded beautifully around the plug and it even took
the valve cover bumps smoothly. It was too much for it to bend around
the spinner ring but I'll be making a fiberglass cowl anyway so it doesn't
matter much.
   I've started making the bulkheads and they're fitting nice and close.
The trick will be keeping it straight.

I also did a first try at the heat gun/bottle canopy trick. It always works
amazingly well even with a rough plug.

The pictures say it all. - Cheers!

kenneth cook · « **Reply #5 on:** November 01, 2014, 04:28:09 PM »

I'm most impressed with this build. A very nice job sir. I can't wait to hear and see the rest. Ken

goozgog · « **Reply #6 on:** November 01, 2014, 04:47:51 PM »

Thanks for the encouragement!
More coming soon.

mike londke · « **Reply #7 on:** November 01, 2014, 10:37:15 PM »

I want one! You know its just as easy to make 2 while you are at it............... LOL

goozgog · « **Reply #8 on:** November 02, 2014, 08:40:10 AM »

It snowed yesterday

so I'm making progress.

   The beauty of making the pine plug is that it's
stable. I can lean on it and it doesn't bend.
   I took some accurate offsets from it and so the
frames and bulkheads are accurate and straight
and, since the sides are molded straight, the fuselage
wants to build straight.

Picture #1 is of the crutch installed in one side with
cyano. When I attached the other side I used Elmer's
carpenter glue on the crutch and then "stitched" the
center joint together with more cyano. It was dead easy.

   The other really good thing is that the dry molded
sides cling to the plug. I put both sides back on the plug,
overlapping the edges and then just cut through both
and "Voila!", the edges meet and joined accurately.
  Picture #2 is the un-sanded assembled fuselage.
You can see how tight the joint is. The whole thing is
feeling light and stiff.

Some weights are....

- Fuselage 0.8 oz - 23g
- Wing 1.6 oz - 46g
- Total so far 2.5 oz - 73g

   I'm planning to cover everything with medium
silk span and dope. It adds a lot of strength for
the weight.

I hope I'm not boring anyone with this.

Cheers!

wwwarbird · « **Reply #9 on:** November 03, 2014, 09:29:49 PM »

My initial thought here was that this project is kind of like the question nobody asked, but this thing is cool.

jim gilmore · « **Reply #10 on:** November 04, 2014, 11:50:55 AM »

That is one very nice build.
Should fly well...and I'd expect a lot lighter than the original plastic models ever were....

Larry Renger · « **Reply #11 on:** November 04, 2014, 07:38:43 PM »

Since you have the molds and know how to use them, how about a stunt version with built up wing? Tee Dee power, of course! Need a set of Super Stunter wings? For this, I could sacrifice a pair from my dwindling supply! ( A true built up wing would be lighter ).

Enlarge the stab, a bit more span,and you would have a fun, unique sport flyer. The envy of all who behold it! Flaps would be icing on the cake, as would be a Rabe rudder.

Any interest in selling sets of shells?

Larry

goozgog · « **Reply #12 on:** November 05, 2014, 03:59:00 AM »

  I've been thinking the same thing Larry but
coming at it from the other direction.
Adding weight as I detail it, makes me ask myself,

" How much do I want to fly this thing?...
Or is it just a sentimental ornament?"

   Right now, it's covered with Silk Span and clear
dope. With the engine, prop, LG, controls and
everything else piled on the scale it weighs
6.1 oz / 174g.
That seems a bit heavy for stunting.

  I suspect it will loop, so then it's about how
far can a Cox Spitfire get through the pattern?
With a flat bottomed foil, probably not too far.
If I go to a symmetrical foil and increase the tail
area, then it's not a model of the model.

   What I'm really getting out of this project is
experience molding wood. I've been working with
balsa for almost fifty years and this is amazing!
Why didn't I do this before?
   I don't know if the raw shells would survive
being shipped so I wouldn't want to sell them.
Thanks for the wing offer Larry (!) but it would be
easier if I just made a wing. Shipping is always a
problem.

  The next thing is to replicate the Top Flight
Form-Flite Thunderbolt or Zero.

Cheers!

goozgog · « **Reply #13 on:** November 08, 2014, 08:12:40 AM »

   Now it starting to look the part!

  The root fairings made a huge difference.
They are a big part of how Spitfires look and
I've read that they gave the original builders
lots of trouble.
I wasn't sure how to do these fairings.

  I used blue painter's tape and made a tape
version of what I wanted. That gave me the shape.
Then I peeled it off the plane , stuck it flat onto
1/16 balsa and cut out two of them.
   What's better for bending balsa than hot water?
Lot of hot water of course, so I boiled the cut outs
in a pot for ten minutes and it bent like pasta.

   Thinking about why I've never molded balsa before,
I'm realizing that it's because cyano glue is what
makes it work. I couldn't do this with Ambroid.

  The plane is covered with silk span and the
controls are working. The wing is held on with
#6 nylon bolts so I can get at the bell crank.
Getting the controls right took several hours.

   The pictures show one of my engine possibilities.
It needs a check up and some buffing to make it pretty.
   I had a vague memory that I might have a genuine
Cox 3 blade prop. I have no idea where it came from
but it was in a drawer. Now I just need to find a Cox
click on spinner for it.

Cheers!

wwwarbird · « **Reply #14 on:** November 08, 2014, 03:20:43 PM »

Looking great!

mike londke · « **Reply #15 on:** November 08, 2014, 05:12:12 PM »

Amazing craftsmanship.

John Rist · « **Reply #16 on:** November 10, 2014, 05:22:07 PM »

Quote from: goozgog on November 08, 2014, 08:12:40 AM

The pictures show one of my engine possibilities.
It needs a check up and some buffing to make it pretty.
I had a vague memory that I might have a genuine
Cox 3 blade prop. I have no idea where it came from
but it was in a drawer. Now I just need to find a Cox
click on spinner for it.

Cheers!

Cox still has spinners in stock. They only have pusher 3 bladed props left.

http://coxengines.ca/cox-049-engine-hub-red-rubber-spinner.html

Larry Renger · « **Reply #17 on:** November 10, 2014, 08:56:46 PM »

Reedie Coxes run either way, so pusher props are actually a bonus! Better line tension. Sure, you need to rework the spinner holes, but the performance advantage is worth it!

goozgog · « **Reply #18 on:** November 11, 2014, 02:52:54 AM »

   Thanks for the link John, but the original
spinner clicked into the hub boss of the
prop. They stayed on pretty well too.
   I'll probably order a few reeds and other
pieces from Cox International so I'll get
that spinner anyway. At least it's genuine
Cox.

   Geesh Larry! Why didn't I think of that!
I really wonder about myself sometimes.

The Spitfire is at the paint and decorate
stage. A little spackle, some throw cushions
and a vase of flowers. It'll look great.

Cheers!

John Rist · « **Reply #19 on:** November 11, 2014, 10:32:41 AM »

They have the hard plastic also:

http://coxengines.ca/cox-.049-plastic-spinner-hub-black.html

goozgog · « **Reply #20 on:** November 12, 2014, 12:49:10 AM »

   The picture shows the Spit ready
for paint. I knew that when I got to
this stage that I'd be fighting with
the temptation to give it scale markings.
Hmmmmm!

   I made some more canopies with
frames this time and doubled up the
windscreen to make it look more like
the injected styrene original.

  The Cox version had clunky stick-on
decals so I probably won't be printing
water transfer ones.

   In the picture she weighs 6.4 oz.
A little heavy.

wwwarbird · « **Reply #21 on:** November 12, 2014, 07:17:41 PM »

I'll take one.

goozgog · « **Reply #22 on:** November 15, 2014, 02:46:56 PM »

Getting close! Now for all the little details........

   The strange thing about this project is
duplicating the cheesy stick on decals and
making sure that I get under spray around
the edges of the camouflage.

  Cox might not have done everything to a
high standard, but After building this, I have
developed a deep respect for traditional mold
and pattern makers. Making injection molds
with this detail without CNC must have been
a serious investment.

   I have learned that the original Cox Spit
weighed 11.4 Oz. As it appears in this picture
mine's at 7.2oz., so I feel optimistic.

Cheers!

Bill Smith · « **Reply #23 on:** November 15, 2014, 07:22:23 PM »

Looks freakin great.
Good weight too.
Do you do requests?

Are you going to do any more?

goozgog · « **Reply #24 on:** November 18, 2014, 02:35:54 PM »

Hello Bill,
   The only requests I usually get are
requests to "Please stop!"
Bill, what do you imagine you might request?

   Really, these planes might go for $$$$ hundreds
on E-Bay but compared to the hours of making one,
that might be cheap.
Not as much fun though.

   I need to get back to building a new F2B plane,
but I would/could whip off a Top Flight P-47
"Form Flight" if I can find some basic dimensions.
They were fun planes and looked great.
Making the plugs for the fuse and wing would be
easy after doing this Spitfire.

I have one last post coming soon showing the Spit
finished. Then I'll let this thread die out.
  I'll wait until Spring before I fly and I might
report about it then.

Cheers!

Bill Smith · « **Reply #25 on:** November 19, 2014, 03:30:01 PM »

My note was somewhat tongue in cheek. I have spent the time to built things like this before.
They are a labor of love and no one can afford the actual cost in labor that you have in it.
It does look great.

goozgog · « **Reply #26 on:** November 19, 2014, 05:17:14 PM »

Awwww $:-\$
I was hoping you'd have
some cool project idea that
you've been contemplating for years.

I think a 1/2 A Heston Racer would
be awesome in molded Balsa.

goozgog · « **Reply #27 on:** November 20, 2014, 02:07:07 PM »

TaDa!
Finished at last.

There's three inches of snow outside
and it's minus 12f. I doubt I'll be test
flying this soon.
If it flies well, I'll report back so I can
brag. If it's a dud, I'll hide it under my bed.

Thanks everybody. - Cheers!

Bill Smith · « **Reply #28 on:** November 20, 2014, 02:20:56 PM »

Heston Racer ? Now that you mention it.

I doubt it will be a dud
We need in flight videos of the spit when the weather breaks.

Ron Cribbs · « **Reply #29 on:** November 22, 2014, 07:25:18 AM »

I have been following this in silence, but I have to say you have done an excellent job!!!

goozgog · « **Reply #30 on:** November 22, 2014, 09:48:04 AM »

Thanks Ron!

   Part of what motivated me to do this was
Dan McEntee's Cox Stuka video (and Bill
Smith's Tree Town Scale 1/2A video).
Amazing fun.
Thanks Guys!

  Many of us have good memories of Cox
planes and when I read about someone
wishing they had a PT-19 I always wonder
why they don't just build one. (?)
Maybe it's just because no one has ever
drawn some plans.
   I volunteer to draw PT-19 plans if someone
can send me some reference. It's not a plane
I have any feelings for but I think it should be
available as a PDF for everyone.
( Complete with rubber bands!)

   I've never posted a video before but maybe
it's time to learn how.

Cheers! - K.

Larry Renger · « **Reply #31 on:** November 22, 2014, 03:18:58 PM »

Would photos and dimensions do? Or, after the AMAexpo, I could lend you one.

goozgog · « **Reply #32 on:** November 22, 2014, 05:14:23 PM »

Hello Larry,
   Shipping airplanes is never easy.
If you (or anyone) send me photos and some basic
dimensions, I can work from that.

   I will probably have to interpret some details like
I did with the Spitfire. Input and ideas from other fliers
would be a good thing.

   If I'm remembering it right,the PT-19 has an open
bottom and you can see the controls. Those sort of
details would make it closer to the original.
   I also think I'd need to draw it for a Baby Bee and
also a product engine.
I will insist on keeping the rubber bands!

If we're going to do this, should we start a new thread?

Cheers! - K.

Larry Renger · « **Reply #33 on:** November 22, 2014, 07:20:06 PM »

I think that the club has a stash of junk parts that I can sen you to keep. We used to use ths PT-19 for training, and have a box of trashed bits, but enough for Your purposes. It will be a couple of weeks before I can gather the stuff, but PM me your address.

The hollow fuselage should be a piece of cake for you in either one or two halves! Maybe bond carbon veil inside while forming? Wrap your form in plastic wrap and use thinned white glue between the balsa and the veil inside.

Ron Cribbs · « **Reply #34 on:** November 24, 2014, 10:05:52 PM »

Quote from: goozgog on November 22, 2014, 09:48:04 AM

Thanks Ron!

   Part of what motivated me to do this was
Dan McEntee's Cox Stuka video (and Bill
Smith's Tree Town Scale 1/2A video).
Amazing fun.
Thanks Guys!

  Many of us have good memories of Cox
planes and when I read about someone
wishing they had a PT-19 I always wonder
why they don't just build one. (?)
Maybe it's just because no one has ever
drawn some plans.
   I volunteer to draw PT-19 plans if someone
can send me some reference. It's not a plane
I have any feelings for but I think it should be
available as a PDF for everyone.
( Complete with rubber bands!)

   I've never posted a video before but maybe
it's time to learn how.

Cheers! - K.

Keith,

I was with Dan a couple weeks before the video'd Stuka flight. We were doing the PT-19 flyathon when Dan decided to put up the Stuka. Unfortunately it was plagued with an engine problem and winds picked up so we scrubbed the flight. I was again in the St. Louis are during his successful attempt, but was unable to see it in person due to work obligations.

I did not grow up around Cox RTF planes, but did see a few as a youngster. I think what you did with the Spitfire is a wonderful thing and I hope to see some video of you flying it.

On a side note I grew up in London Ontario as well as Mississauga Ontario, if I am ever up that way visiting my parents I will look you guys up!

Ron

Glenn (Gravitywell) Reach · « **Reply #35 on:** November 25, 2014, 01:36:58 PM »

I actually learned to fly on a Cox Spitfire. Looking back, that was probably a bad idea! LOL Mine was the solid dark green one....wished I still had it, she was soooo pretty!

Juan Valentin · « **Reply #36 on:** November 25, 2014, 04:11:33 PM »

Hello Keith
I just bumped into your Spitfire build and is awesome. I have always wanted to do the corsair and you have given me the inspiration to try. I saved all the photos of your build to use as reference. I don`t know when I would be able to do one but now I have a better Idea on how to do it. I have always liked the COX plastic airplanes and my first flight was on a P-40 Warhawk with about 20 feet of lines when I landed(crashed) I was very dizzy, It was a lot of fun.
Juan

goozgog · « **Reply #37 on:** November 27, 2014, 05:13:27 AM »

Hey Ron, If you're ever up here the Balsa Beavers
circle is in Centennial Park under the approach to
Pearson International. You can see Mississauga
City Center from the circle.
We'll dig you out a plane!

Glen, you're a rare person. I've never heard of
someone who learned to fly with one of these.
There must be a story there? Did the plane last
very long?

Juan, whenever you post, I look at beautiful
Puerto Rico in your photo's. Being able to fly C/L
amid all that tropical green seems like a dream.
About 20 years ago, I spent 6 weeks sailing
along the south coast from Fajardo to Boqueron.
It is still one of my favorite places on this planet.
Count me as jealous that you live there. :-)

Juan Valentin · « **Reply #38 on:** November 28, 2014, 05:31:56 PM »

Hello Keith
I`m glad you enjoyed your stay in the island. I live about 35 miles north of boqueron beach on the north coast of the island. I drive on sundays to be with my buddies at the Prop Busters flying field in San Juan. Lately I haven`t done much flying since I have been working on a motorcycle project I have. Two weeks back I rode my Triumph Thruxton to boqueron and it was really nice the sea looked like it was flat. The weather here is very good for controline flying but you have to do your flying in the morning since wind picks up by mid day. We are a small group of fliers and like every other C/L group is not easy to recruit new fliers. I live about 90 miles from San Juan which means getting up at 5 am to be there at 7am. The guys are friendly and we welcome visitors.Take another vacation and come by.
Juan

goozgog · « **Reply #39 on:** May 19, 2015, 05:27:55 PM »

Finally! The weather was good enough for a flight test.

Many thanks to Paul Emerson for the video and editing
and to our Web Master Doug Blackmore.

Paul had trouble keeping the little @#$%^& in frame,
but it flew nicely and I even managed a loop.
Really, it works much better than I remember the Cox
version did.

The video title is a bit of a lie. The actual first flight
was performed by Chris Brownhill. There's a reason he
wins at Muncie.

Thanks to everyone, Larry Renger, Chris, Paul and Doug
but most of all, the legendary crew of Cox Manufacturing.

Ron Cribbs · « **Reply #40 on:** July 11, 2015, 01:26:31 AM »

Keith,

I just watched the video, Bravo!

A testament to your skills as a builder, hope you continue to make more of these.

Ron

goozgog · « **Reply #41 on:** July 12, 2015, 05:33:34 PM »

Thanks Ron,
I built the Spitfire this
winter instead of my next CLPA
"world beater". It was almost the
same amount of work but I learned
a lot about alternative structural
techniques.
Lighter is always better.

The Spit flies decently. I wish the
video caught the loop in frame but
I surprised Paul and his mini camera.
Now I'm being told that I should
enter Fun Scale with it.
Does a model of a model count?

Cheers! - K.

RknRusty · « **Reply #42 on:** August 01, 2015, 09:31:55 AM »

I don't visit the 1/2A forums nearly enough. I'm glad I found this thread, and will read it in more detail. Meanwhile I skipped to the end to see how it comes out. And it's remarkable. I think your worries about power to weight were for naught. She jumped off the ground and hauled ass around the circle. I hope you will get some more of your Spitfire excursions on camera. Maybe farther back so the camera operator doesn't have to play chase lol.

In any case, that's one to be proud of. Very nice job, and thanks for sharing it with us.
Rusty