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Author Topic: SIG Super Chipmonk  (Read 10614 times)

Offline Gerald Schamp

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SIG Super Chipmonk
« on: March 19, 2016, 03:12:46 PM »
Is the SIG Super Chipmonk Classic legal or Nostalgia Class legal?

Offline tom brightbill

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Re: SIG Super Chipmonk
« Reply #1 on: March 19, 2016, 03:52:33 PM »
I believe the Van Loo Chipmunk is classic legal, but the Super is not.
« Last Edit: March 19, 2016, 04:46:33 PM by tom brightbill »
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Offline Gordon Van Tighem

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Re: SIG Super Chipmonk
« Reply #2 on: March 29, 2016, 01:27:51 PM »
Joe Dill Chipmunk from RSM, too.
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Offline Air Ministry .

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Re: SIG Super Chipmonk
« Reply #3 on: April 26, 2016, 09:38:10 AM »
Theres another very Chipmonk , with the very designer , the other very day , thats very N30 Legal .


Offline Terrence Durrill

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Re: SIG Super Chipmonk
« Reply #4 on: April 26, 2016, 07:02:58 PM »


    You might enjoy this site on the SIG CHIPMUNK.  Check it out    D>K     H^^


                          http://members.zumatel.net/mdgretz/Chipmunk.htm


                                                                                                    y1

Offline Gerald Schamp

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Re: SIG Super Chipmonk
« Reply #5 on: April 27, 2016, 12:01:46 PM »
Thank you for the info, very interesting. I think at one time, Dave Fitzgerald wrote a fairly detailed description of what he changed on his Chipmonks. Neat airplane for sure, one of these days.

Offline Andrew Tinsley

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Re: SIG Super Chipmonk
« Reply #6 on: May 02, 2016, 01:01:05 PM »
I picked up a Super Chipmonk kit last year. It looked very snazzy on the box art, but looking at the plans, it had a very pointed LE. I then thought it might not be a good performer and packed the box away. Was this a good move or are there points that need modification to produce a good flyer?

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Offline rustler

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Re: SIG Super Chipmonk
« Reply #7 on: May 02, 2016, 01:37:36 PM »
Yes Matt, and if one looks in the nostalgia listings, Pete Tindalls's CHIPM O NK is listed. With an O not a U.  D>K

Interesting point here. The photo of Pete's Chipmonk above is of his updated design for this year's W/C's. Would this qualify for Classic/Nostalgia/Etc.?
Ian Russell.
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Offline Randy Powell

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Re: SIG Super Chipmonk
« Reply #8 on: May 06, 2016, 08:31:30 PM »
Gerald, your Super Chip will be awesome. Can't wait to see pics.
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Offline Mel Gray

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Re: SIG Super Chipmonk
« Reply #9 on: May 07, 2016, 12:54:32 PM »
Hi Gerald,

Attached is the letter you refer to written by Dave Fitzgerald concerning his Chipmunk mods.

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Offline TigreST

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Re: SIG Super Chipmonk
« Reply #10 on: May 08, 2016, 11:20:15 AM »
I transcribed the pdf letter from Dave Fitzgerald to Walter regarding his mods to the Chipmunk, for fun (?). Anyway here it is:
Note in the wing section #7 deals with wing tips and lead out location. I could not decipher the blank spaces so xxxxx's are used to  denote this.  I believe it's a relatively accurate transcription.  If not you can copy and paste and edit as you wish.  Rather interesting changes made my Dave.



118 Banbury Way
American Canyon, CA, 94589
November 20, 1989


Dear Walter,
I just got your letter last week about the Chipmunk, I guess the zip code I gave you was wrong.  It has been a while since I built the kit Chipmunk so I’ll try to remember what I did.
First, I think the .46 will be a great engine for the plane. One of the challenges will be to come up with a reliable way to adjust the needle through the cowl and not hit the muffler. I soldered an extensions (as short as possible, the longer it is the more vibration and bad settings you’ll get) and a brass slot car gear on the end, or an allen head screw.

Now for all the airframe mods. The basic kit does very well, some simple change will help a lot though. These were from my best airplane.
 Page 1 of 6.

Fuselage:
1) Narrow it from the kit drawings; make it only wide enough to fit the engine.

2) Change the balsa bulkheads from the nose back to the leading edge to plywood.

3) If you use a .46 use 1/16th plywood doublers on the nose, insulate the unused tank space with Styrofoam (vibration damping).

4) Reinforce the nose –leading edge forward -with 1 exterior layer of a fine mesh glass cloth- the .46 really shakes up the plane compared to a .35.

5) Completely seal the tank compartment from the rest of the fuselage, I’ve lost 2 airplanes due to fuel soaking and what I thought was a sealed compartment.  If you can make the tank removable (sliding forward) it will help when trimming the upright vs the inverted engine runs.

6) Lengthen the fuselage behind the wing by 1 1/2 “ – longer tail moment- better turns.

7) Increase the Stab span by 2” . Use a hardwood mount similar to the  main gear-stronger and removable for travel.

2-6

8)Fill in the gap under the rudder-stronger.

9) This fuselage design flexes a lot behind  + at the wing trailing edge,  so when you form the top blocks along the top of the fuselage, instead of using 1/8” balsa, use 3/32” and form 1 continuous top block – nose to tail – cover up the cockpit section, sheet right over it, this is where the fuselage flexes, right at the aft corners of the cockpit side wall.  If you don’t sheet it over + fly a lot, you will get stress cracks. The large canopy still gives you lots of room to put in a pilot.

10) The Cowl:  Sand down and narrow the cowl to fit the new  fuselage width. Be very careful when carving and drilling the support holes. The cowl can last the lifetime of the airframe if you make it a perfect  fit.  Absolutely 0 stress on the sides. Also- extend the motor mounts to the front of the cowl and use 2 screws into the mounts, behind the spinner.

11) Seal only the elevator hinge line with fastcalo  (sp)- scotch tape.

3-6

That’s all I can think of on the fuselage.

Wing: 

1)Span increase, lengthen the inboard wing 1” and lengthen the outboard so you now have equal span wings.

2) Flaps, change the flaps so you now have 1 ½” longer outboard flap.  This means you’ll have a fixed tab on the inboard side.

3)Gear- change the balsa doublers to 1/16” plywood for mounting the gear blocks, also tilt the blocks aft so it lays right up against the main spar.  You can twist the gear wire later.

4) Center section planking – leading edge only, notch ribs on the leading edge 1/16” top and bottom, then double plank the leading edge.  I have a 9 year old Chipmunk with a rebuilt center section that fatigued even with the double planking.  It needs to be a little stronger.

5) Replace the bellcrank platform balsa rail mounts with spruce.

6) Outboard wingtip, build a small box +use lead shot for adjustable tip weight.

4-6

7) Inboard wing tip – the plans have the lead out position very wrong.  Build the tips with 5 ribs (easier to cover) and the lead outs need to be adjustable from nearly the leading edge back to the rear lead out on the plans.  Because of the leading edge sweep the lead outs will end up near the lead xxx  1”xxxx , the wing tip, or about ¼”  to the xxxx  at  the CG – which is about the ¼ chord point at the fuselage.

8) You may have your own preference on how to set up the controls, but I set them up for an average “speed”, 1 to 1 flaps to elevator, and 45’ up + down.

All these changes will give you a slight larger airplane and should come in around 50oz’s if your careful!
Above all else if the kit wood is not very light, throw it away after using it as a templates.  If you keep it very light and strong,

5-6

You’ll end up with a Nats caliber machine.  – Avoid quick links with the .46, it will shake them loose in some cases.
If you think of any other questions write again or call me at home or leave a message on my machine at (707) 552 – 3355.

Dave Fitzgerald

If I think of any more I’ll write again.
Tony Bagley
Ontario, Canada

Offline Walter Hicks

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Re: SIG Super Chipmonk
« Reply #11 on: May 14, 2016, 08:51:36 PM »
Gerald, that letter was written to me in the early 90s by Dave. I constructed a scratch built foam wing Chipmunk per his specs with an ST .46.

It weighed 46 oz with buffed out Super Poxy Paint and flew very well.


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