Building Goldberg Super Chipmunk Advise
Jerry Samsen
I just picked up a Goldberg Super Chipmunk kit for $40 at a local swap
meet.
Does anyone have any advise on building this kit? I plan on using an
OS61FX 2-stroke and build the flap option.
I also plan on installing two aileron servos in the outboard wings versus
the single servo and bellcrank arrangement called for in the plans.
--
Jerry Samsen
SpectraNet International
jsa...@firstworld.com
jsa...@ix.netcom.com
Fred Herrmann
Everything you say sounds good.. I built mine with the bellcranks and am
having no problems.. I've got a pic of it on my web page.. It flys great..
I've got a surpass .70 on mine.
In article <5rm3r0$r7g$1...@news.connectnet.com>, jsa...@firstworld.com
says...
--
Visit Fred's Semi-Live Cam and R/C Chat for up to the Minute R/C Updates!
http://fly.hiwaay.net/~fherrman
"If it doesn't kill you, it will only make you stronger!"
DMich27020
>Subject: Building Goldberg Super Chipmunk Advise
>From: "Jerry Samsen" <jsa...@firstworld.com>
>Date: Tue, 29 Jul 1997 18:04:01 -0700
>Message-ID: <5rm3r0$r7g$1...@news.connectnet.com>
>
> I just picked up a Goldberg Super Chipmunk kit for $40 at a local swap
>meet.
>
>Does anyone have any advise on building this kit? I plan on using an
>OS61FX 2-stroke and build the flap option.
>
>I also plan on installing two aileron servos in the outboard wings versus
>the single servo and bellcrank arrangement called for in the plans.
>
>--
>Jerry Samsen
>SpectraNet International
>jsa...@firstworld.com
>jsa...@ix.netcom.com
>
>
>
>
You got yourself a nice deal there! The OS should work fine in this
plane, however, you won't need the flaps.
I had one about four years ago and enjoyed it very much. You might
consider replacing the ABS with Fiberglass parts to save yourself some
aggravation. I have noticed on mine and on others that I have seen fly
that the plane wags its tale sometimes while flying. If you see this,
don't be too concerened.
Have fun.
Dave
RSabast
You are in for a treat. I have one powered by a K&B .65 that does great.
It's a fairly light plane for it's size. Go with a fiberglass cowl, it's
worth it easily. Also, beef up the landing gear points in the wings with
real (not light or a/c) plywood. The gear on mine folded on a not-so-hard
landing. Others have said the same thing. I used the bellcrank set-up
and it does fine.
Bob
Jerry Samsen
Thanks for all of your suggestions. I'll let you all know how it turns
out. I plan on doing an excellent job so it may take several months to get
the job done.
Hopefully I'll have my web page done then also and post some pictures.
Jerry Samsen wrote in article <5rm3r0$r7g$1...@news.connectnet.com>...
RCPILOT48
>>Does anyone have any advise on building this kit?
Mine had the twin servos. I changed from the wing LG to a fuse mount right
in front of the wing attachment. Made life much easier for the not so
great landings. Met an untimely death at the upside down bottom of a
Cubann 9 that was supposed to be a Cuban 8. Good Luck. Let us know how it
comes out. Andy
Sam and Sonja Sorem
I second the fuse mount landing gear. I still have my Chipmunk,
although I haven't flown it since my MW Extra took to the skies. I
used the single aileron servo and haven't had any problems with it. I
put the flaps in but rarely use them. Get a fiberglass cowl from
Stans Fibertech. Other than the cowl/pants, and the landing gear,
which seems to be inherent in all Goldberg designs, the plane is one
of the best flying planes I've ever seen.
Sam Sorem
Dave Tatosian
In article <5rm3r0$r7g$1...@news.connectnet.com>,
"Jerry Samsen" <jsa...@firstworld.com> wrote:
> I just picked up a Goldberg Super Chipmunk kit for $40 at a local swap
>meet.
Yikes - what a great buy!
>Does anyone have any advise on building this kit? I plan on using an
>OS61FX 2-stroke and build the flap option.
So far so good (though I preferred an OSFS91S in mine). You'll undoubtably get
some flak here for building with flaps. Set mode = ignore ;^) Flaps add yet
another thing to play with - as well as helping to tighten up those loops...
>I also plan on installing two aileron servos in the outboard wings versus
>the single servo and bellcrank arrangement called for in the plans.
Absolutely correct. I did the same and the control surfaces came out
slop-free. You'll have to mount the servos on their sides - the wing is too
thin to stand them up. Lots of ways to do this but the easiest is to buy
the nylon "T" mounts and screw them into hardwood rails installed in the wing.
Or you can frame the servo bays with light balsa and then fit thin
plywood hatch covers to match - and attach the servos to the inside of the
hatch covers.
The CGM Super Chipmunk is a fine model and a good kit, but there are
a few nits imho. So, additional suggestions:
- beef up the landing gear mounts. Surround the LG blocks with angle stock and
epoxy everything so you have a very solid base for the gear. Even better:
replace the plywood LG blocks with hardwood parts, and surround those with
angle stock.
- unless your a big fan of painting plastic bits, throw out the plastic wing
tips and belly pan and carve/fabricate those parts out of balsa. You can't put
film over that plastic stuff. Carving those teardrop wing tips out of balsa
block is a lot easier than you might think. Same for the belly fairing.
- spring for a fiberglass cowl (R/C City sells nice ones). The 'glas cowl is
lighter than the ABS cowl, yet it'll last longer (won't crack as quickly). R/C
City also sells 'glas wheel pants, fwiw.
- take your time putting the fuse together - triple check the fit of the (4)
long pieces of lite ply that make up the basic box fuse. I had to fiddle with
the slots 'n' tabs to assure that I ended up with a straight fuse. And don't
rely on matching those parts to the plans - the plans are *not* to scale - so
everything is shifted a bit. Dry fit and adjust the parts until you're happy
with the "straightness".
- when you get around to needing stuff like wing and stab incidence, engine
thrust angle, etc, don't bother searching through the plans or the manual -
that information isn't to be found. Larry King at CGM was kind enough to
provide that information, as follows:
- wing incidence: +1/4° (make it zero and you should be fine)
- stab incidence: 0 degrees
- engine thrust angle: 1.5° right thrust, .5° down thrust
- as-designed wing dihedral: 2 11/16" as referenced at rib #11
- Note: the dihedral on this wing appears excessive to me. I wasn't looking
for a pattern ship but didn't want trainer-level stability either. I reduced
the dihedral by half - so it's now similar to the dihedral used on my US60.
When you go to join the wing halves using the dihedral "jigs", you'll see what
I mean here. It was nbd to change this, fwiw..
- watch out for asymmetry in the 2 lite ply firewall parts. Depending on when
yours was kitted, these pieces may have been cut with a blown-out die (like
mine). Not being comfortable mounting my 91FS to lite ply anyway, I cut my
firewall from 1/4" AC grade ply with an additional piece of 1/8" AC ply
sandwiched behind it to provide depth for the blind nuts.
- Examine the fuse area behind the former just behind the rear wing bolt
blocks. If you agree that this looks a bit weak, consider beefing it up a bit.
Also add some 1/4" triangle stock to the inside butt joint between the fuse
sides and the fuse bottom when you glue up the fuse. You'll be able to round
the outside of that joint for appearance sake without sacrificing strength.
- If you're thinking of using the same trim scheme that CGM used, and you're
going to do it with film, consider sheeting the entire top of the wing.
It'll make those stripes real easy to install over the white base film -
especially if you use CGM Ultracote...
If you have any other questions as you proceed to build, drop me a line. If
you need inspiration, I have a bunch of pictures already scanned that I can
email you...
Cheers!
/dave
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
<> Dave Tatosian tato...@eng.pko.xxx.com <>
<> Digital Equipment Corp. Alpha Server Engineering <>
<> Parker Street Campus Maynard, Massachusetts <>
<> !!NOTE: Please replace "xxx" with "dec" to respond by email!! <>
<><><><><><><><><><><><><><> AMA 548313 <><><><><><><><><><><><><><>
Disclaimer: Opinion and content is mine alone, and unlikely to be
shared by my employer, etc...
Stearman17
The Goldberg Chipmunk is a very well engineered kit and I recommend
building it just as instructed. A common mistake made on this kit is
putting in the landing gear KEY blocks. It is clearly shown in the
instruction book but easily done wrong. Flaps do help this plane a great
deal since it is very clean and doesn't slow down easily. I flew mine for
over three years with a K&B 61 and still was able to sell it less engine
and radio for $200. You won't be sorry with this kit. Incidentally I
used a single aileron servo as shown on the plans with no difficulty at
all. You will find that mounting the cowl with the engine in place can be
awkward and requires you to have quite a large hole for the engine cyl hd.
If I were to build this plane again, I would split the cowl along its
vertical centerline for ease of assembly. Hope this is of some help to
you. Pete (Stear...@AOL.com)
VideoFlyer
Beef up the landing gear mounts, ditch the ABS cowl and go with
fiberglass......you'll be a happy pilot. Its a great plane. I fly mine
with an OS 91 4-stroke, no flaps, oversized wheels (since I fly on grass)
with no wheel pants (they came off on the first landing). I love it!
VideoFlyer@ aol.com
chris
Doug Noel wrote:
>
> joe zito wrote:
> >
> > DMich27020 wrote:
> > >
> > > >Subject: Building Goldberg Super Chipmunk Advise
> > > >From: "Jerry Samsen" <jsa...@firstworld.com>
> > > >Date: Tue, 29 Jul 1997 18:04:01 -0700
> > > >Message-ID: <5rm3r0$r7g$1...@news.connectnet.com>
> > > >
> > > >meet.
> > > >
> > > >OS61FX 2-stroke and build the flap option.
> > > >
> > > >the single servo and bellcrank arrangement called for in the plans.
> > > >
> > > >Jerry Samsen
> > > >SpectraNet International
> > > >jsa...@firstworld.com
> > > >jsa...@ix.netcom.com
> > > >
> > > >
> > > >
> > > >
> > >
> > > You got yourself a nice deal there! The OS should work fine in this
> > > plane, however, you won't need the flaps.
> > >
> > > I had one about four years ago and enjoyed it very much. You might
> > > consider replacing the ABS with Fiberglass parts to save yourself some
> > > aggravation. I have noticed on mine and on others that I have seen fly
> > > that the plane wags its tale sometimes while flying. If you see this,
> > > don't be too concerened.
> > >
> > > Have fun.
> > >
> > > Dave
> >
> > according to the plans. It will not fit properly extending the exhausts
> > as required. The bend will probably furnish to much back pressure for the
> > K & B .61. Anyone else have this problem ?
> >
> > Joe in Reno
>
> Yep,
> Got out all of my old files and grinders and had to do away with a lot
> of metal to get it in the cowl, then had to add extensions to get
> exhaust back out of the cowl.
>
> DougIam thinking of buying a chipmunk goldberg, with an os surpass91 on it
and wondering if its something Ican fly Ihave been flying a tranier and
a big lazy bee since this spring and whant a plane that can stunt but
still can manage what do you think?
chris-...@worldnet.att.net PS: the bee is a blast! have a
saito 56 on it and it can really loop and roll!
Mr. Wizard
I had the same problem when I tried to install one in a Hobbico Extra
300 the engine was mounted sideways.
If that is what you are doing, I would suggest that you buy a exhaust
manifold extender, that should give you the clearance that would be
required to exit the pipes under the fuselage.
On Thu, 31 Jul 1997 22:48:10 -0700, joe zito <joe...@inetworld.com>
wrote:
SFA 60920
Due to E-Mail spamming bots my reply address is incorrect.
Remove the "f" from my isp
Deanjeffre
Jerry,
I built a Goldberg Chipmunk a couple years ago and made some of the same
modifications that you want to make. Placing 2 servo's in the outboard
wings is a good choice. I do suggest you reconsider the OS61. I first
put a Saito .91 on mine and now have a Supertiger .90 2 stroke. The .90
is a powerhouse (perfect engine for this plane)