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Building Tips and technical articles. => Building techniques => Topic started by: chris hornady on December 23, 2010, 07:07:41 PM
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Good evening and Mary Christmas to all. I was checking out a hobby shop a friend of mine told me about today and i found a super chipmunk kit on sale so i have spent the rest of the day jiging up the wing and building the fuse. My questons are 1. The plane feels very heavyand it is just framed up. The balsa is pretty good wood it is just a bulky solid design. Is this normad for the chipy or do i need to stard doing some major lightning work?
2.should i go with a fox 35 with a hemi kit or do i need to go ahead and go with a 40 size engine?
3. are there any minor improvements that anyone knows about that will make the air craft fly better or should i go buy the plans?
Thanks for all of the help.
Chris Hornady
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Ditto what Ty said. The Fox will fly it, but you'll wish you had more power. I'd even ditch the plastic engine cowl and carve something out of balsa. All that plastic is a LOT of weight.
The Sig Chipmunk is fantastic plane. Good luck and post your progress.
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HI Chris,
Nothing to add to the "building" part! The guys have covered that. ;D The Super Chipmunk flies really well, and I have seen some "box stock" kits fly pretty good!
I don't know your level of experience or expertise, so I would suggest the OS .46LA for power. Very reasonable priced engine that will haul the mail very well in that model. Of course, you could pop for an Aero Tiger .36 or PA .40UL, or some of the other "competition engines" if you have the money, but the .46LA will do just fine. User friendly and dependable.
Merry Christmas!
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Thanks for all the good advice. One more question what size thank should I use if I put a OS 40 or 46la on it i want it to be able to fly it in competition this summer.
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Go with a 4.5 or 4.75 ounce tank. You can always short tank it, but can't add more fuel if too small. H^^
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Thanks for all the good advice. One more question what size thank should I use if I put a OS 40 or 46la on it i want it to be able to fly it in competition this summer.
Hi Chris,
I definitely suggest the .46LA over the .40LA. Line size is no longer governed by engine displacement, so you can fly a .46 engine if the overall weight is not above a certain limit (well with in what the Super Chip should come in at.
Plus I have literally never seen troubles with the .46. I have seen some fiddling having to be done with the .40. The .40 just doesn't appear to be as user friendly out of the box. And another BIG plus is that the .46 is lighter than the .40. Both are built in the same crankcase! More power, lighter, can use the same size lines, and a touch easier to run= no brainer! ;D
Big Bear
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I watched Don Shultz fly is extremely cool Chip with a blessed ST46. Wonder flying plane.
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what is the max finished weight of the plane if i use a 46la?
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One reason why the Chipmunk has such a good reputation is that light or heavy, they usually fly very well. Shoot for under 50 ounces, but with an LA-46, even a few ounces above that will still get you a good flying plane. 8)
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One reason why the Chipmunk has such a good reputation is that light or heavy, they usually fly very well. Shoot for under 50 ounces, but with an LA-46, even a few ounces above that will still get you a good flying plane. 8)
I agree! ;D
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HI Chris. Shoot for 40 oz., but I think mine was at 48 and flew quite nicely. Too much over that and some of the maneuvers will suffer. H^^
Ty, 40 oz for a typical kit built Super Chip is probably not realistic. However, 45-48 oz is very obtainable and will fly great as yours does. I just didn't want Chris to be disappointed if he didn't get down to the 40 oz weight or sacrifice strength trying to get there.
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Is wraping in copper wire and soldering to make my eyelets on my leadout's still a ok way of doing it?
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Don't solder the lead out's as this will cause a "stress riser" and they could break.
Just wrap them like the AMA rules require.. Again don't solder.. n~
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Were can I go to fiand out how to do that?
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Chris ,
This is a good tutorial for B/C's and leadouts ...
http://stunthanger.com/uploads/bellcrank%201.pdf
Just wrap with copper wire and heat shrink tubing , on the exit cable(s) , just like on the B/C end of things .
Rob K.
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Just like these
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Thanks for the follow up photos , Lee y1
(I was in a hurry) #^
Rob K.
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I have one of these kits, I have cut a new set of ribs and saved probably an ounce already? You have set me a challenge to build the thing at around 40-45oz, that means throwing away a lot of the kit wood! I'll probably leave it in the box and sell it on e-bay in a few years! ;D
Cheers
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Jim Ciero has a neat Super Chipmunk on the rear cover of Contro Line World # 1 for Jan 2011, Thank's John Brodak for a great mag. #^
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Thanks for all the good advice. One more question what size thank should I use if I put a OS 40 or 46la on it i want it to be able to fly it in competition this summer.
I have a couple of OS FP .40s, both are Randy Smith tuned. 7:00 minutes on 3 1/2 oz. of 10% nitro, 22% oil. The OS 46 LA is out of the box, but has an extra .015 head gasket. That uses 4 1/4 oz. (same fuel mix.) Again 7 minutes. I like both engines.
Re the SIG control horns: If your kit came with the nylon-on-wire horns, I'd suggest you set them aside for a plane you want to hang from the shop ceiling. They are not good in the wind and will flex to a fault. (like earth quake, if you know what I mean)
Don 4029
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I built a Super Chipmunk two years ago. When I opened the kit I noticed all the balsa was the heavy stuff. I put an O.S. LA 40 on it and it flew awful. Now after being a Hangar Queen for two years I decided to lighten it up and get it in the air. I removed the plastic wheel pants and cut the nose cowl as shown in the picture. I cut an 1 1/2" off the rear of the cowl and I cut the bottom 2/3's off it. I used Wiss Tin Shears to cut it and they worked great, I didn't even have to deburr it. After I built it I needed to add 2 1/2 oz. to the tail to get the CG right. Now after removing the wheel pants and cutting the cowl down I was able to remove 1 1/4 oz. of the tail weight to get the CG where it belongs. Now it flies great. I had it at the field today and this could turn out to be one of my best flying planes. I'll post a picture of the plane in another post because the file is too big to fit on this post.
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Here's the picture of the Super Chipmunk right after it was built.
If I were going to build another SIG Chipmunk I would at least replace all the heavy balsa planking, the rudder, horizontal stab. and elevator that SIG supplied in the kit with lighter balsa. I probably would also reduce the thickness or the fuselage planking from 1/8" that SIG supplies, to 3/32" or 1/16". I'd flat sand the ribs and fuselage bulkheads to get some weight off them too. Sounds like too much work to me to cut new ribs and bulkheads. The ribs are capped anyhow so they could be sanded to be quite a bit thinnerwithout sacrificing too much strength. I would also consider moving the engine back or moving the wing forward about an inch since the first one I built was nose heavy.
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I ordered and recieved a Super Chipmunk kit a year or so ago. After opening the shipping package I resold the kit without even taking the plastic off, the box felt that heavy.
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I got one years ago. Like most of them it was really heavy. I gave the kit away to a friend to build with the admonition that I wasn't doing him any favor.
Dennis
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The Sig Chipmunk can be a really good flying plane, hopefully a revived Sig will produce some new ones with lighter wood.
I know it's a longshot, but I bet if they did an ARF Chipmunk they could sell a bunch of them. y1
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For all you Chipmunk fans, I'd suggest you look at the new RSM kit of the classic legal Chipmunk by Joe Dill. EXCELLENT
wood and hardware, much more scale-like, just a bit smaller than the Sig version. All laser cut wood, nice plans, some of
the best horns on the market. All of us CAN build this one in the low 40-ounce range, should be an outstanding flyer.
Great looking ship, can't wait to get this one built!
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As the proud owner of a Sig Chipmunk kit, won as a monthly drawing prize on this site, I'm looking forward to building it for NOS 30 competition. As far as replacing some (much) of the wood - no issue at all as the kit will provide, at the least, excellent templates. A lot easier than my usual practice of starting from scratch. As this is such a good flying plane and timeless design the extra effort will be worth it. 8)
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As the proud owner of a Sig Chipmunk kit, won as a monthly drawing prize on this site, I'm looking forward to building it for NOS 30 competition. As far as replacing some (much) of the wood - no issue at all as the kit will provide, at the least, excellent templates. A lot easier than my usual practice of starting from scratch. As this is such a good flying plane and timeless design the extra effort will be worth it. 8)
That's actually a good way to look at it Pete, and I agree 100%. Other than some of the custom stuff, most kits can benefit from a lot of wood substitution etc. We've all gotten pretty spoiled by the quality of most kits these days. I know most here would agree, looking back I can't believe some of the kits I actually built right out of the box. Most of them would have been total garbage by todays standards.
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So true. H^^
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I built mine without the plastic parts. It came out at 41 ounces, powered by a OS LA46. It flies like a dream.
One question: I tested one of the nylon/steel steering horns to destruction. I had a lot of trouble trying to twist the horn round the steel connector. How reliable do you find the issued nylon horn? Is it a must to replace it? Personally I feel confident about the quality.
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I built mine without the plastic parts. It came out at 41 ounces, powered by a OS LA46. It flies like a dream.
One question: I tested one of the nylon/steel steering horns to destruction. I had a lot of trouble trying to twist the horn round the steel connector. How reliable do you find the issued nylon horn? Is it a must to replace it? Personally I feel confident about the quality.
There have been MANY reports of those horns failing.............. it's too easy to change them out and at least guard against a potential problem that seems to hit all who have used them.
Big Bear
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There have been MANY reports of those horns failing.............. it's too easy to change them out and at least guard against a potential problem that seems to hit all who have used them.
Big Bear
Listen to Bill!!
Bottom line is that you just don't want to risk it.
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y1 Great tutorial http://stunthanger.com/uploads/bellcrank%201.pdf
#^ I now install my bell cranks & leadouts this way with great success. <= I used to solder, and crimp, and I had a couple of failures, at these locations, and it cost me a couple of irreplaceable planes, and now I no longer solder! n~ LL~
Chris ,
This is a good tutorial for B/C's and leadouts ...
http://stunthanger.com/uploads/bellcrank%201.pdf
Just wrap with copper wire and heat shrink tubing , on the exit cable(s) , just like on the B/C end of things .
Rob K.
#^
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Chris ,
This is a good tutorial for B/C's and leadouts ...
http://stunthanger.com/uploads/bellcrank%201.pdf
Just wrap with copper wire and heat shrink tubing , on the exit cable(s) , just like on the B/C end of things .
Rob K.
y1 Great tutorial #^ <= I used to solder, and crimp, and I had a couple of failures, at these locations, and it cost me a couple of irreplaceable planes, and now I no longer solder! n~ :! 8)
#^
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Has anyone ever seen this kit modified to the original DHC-1 version? Thnaks, Mike :)!
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Thanks Ty :)
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There is a plan for more scale Chipmunk stunter from the '50's. I think it was designed by Geoff Pentland of Oz ;D It's quite a big model for the power available back then, I have a copy upstairs in my office (tiny room full of stuff, files and a computer ;)) Kookaburra were the people that published it.
Cheers
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Were can I go to fiand out how to do that?
http://www.brotherhoodofthering.info/flightline/photos/photo-thumbnails.asp?albumid=120
http://www.brotherhoodofthering.info/flightline/photos/photo-thumbnails.asp?albumid=119
here is a pictoral about how I do it,
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Peter Tindall flew a Chipmunk in England , did a series, removable wing etc . ST 46 .
Was about 74 , 56 in. span I think.With the big squareish canopy, Kraft were mentioned for canopy ?
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Tried to look at the links, but I have not registered yet. Haven't got caught up on this forum yet. It is hard when you only get the use of a computor for a few minutes a day while in Tuscon. Then two days each way for travel. Nothing like being specialists. At least this site lets you look at the open portion without logging in. D>K
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Has anyone ever seen this kit modified to the original DHC-1 version? Thnaks, Mike :)!
Michael,
Is this the plane you're looking for? I have wanted to build this plane since I first saw it in Guy R Willams' "The World of Model Aircraft" . . . and that was many moons ago. I prefer the canopy of the DHC-1 to the bubble canopy, and I also prefer the cowl that carried over from the Tiger Moth; it's got a more classic stunt look to it.
This plate came from the UK, so I suspect the kit or plans may have originated there. Can anyone ID this plane?
Damian
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Isn't this the Pete Tindell?
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Isn't this the Pete Tindell?
I wouldn't know him from Adam, but I can tell you you're in the right ballpark. The photo originally came from The Croydon Advertiser and according to PAMPA Pete Tindal lives within 50 miles of Croydon.
The book I have was published in 1973; the plane Matthew is referring with a ST .46 to could be a later variant. The muffler on the plane looks like an old O.S. Jetstream; a .35S would be my guess.
Well John, if it turns out that you were able to ID the pilot you would deserve a gold medal.
H^^
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Yes that is Pete Tindal, I've judge his flights a few times, and flown against him as well. A very good flyer, and still at it, That Chipmunk was in the Aero Modeller plans service back in the '70"s. Its in the X-plans list from MY Hobby Store No. CL1338.
Cheers
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Hi Damian,
Didn't know I still had some fans out there,unfortunately don't have any drawings, these were early days of building frenzy and all models were just a slight variation of the previous one.....by 1974 I was on the 7th one which had morphed into military trainer and that's really where they have stayed. they did however, grow in size as no.7 was realy where I wanted to be in relation to the JVL version where it all started. No.4 was fox 40 powered and won me the Nationals (Gold Trophy) in 74 and was further developed to No.7. This was st46 powered and used to obtain 14th in the 76 WC's. This was the only plan published both in the States and the UK........77 saw the first Merco 49 powered Chippy win the nats again with a further 14th world place in78 with a Merco 61 Chippy..........and so on...........in the early 80's I started playing with other designs from jet style to Cap 21 ish.............but although the maths were the same as the big Chippy's, judges were so used to seeing me fly them that although I still did well I was always asked when is the next Chippy........................having had a break from cl from the mid 80s, I started my own model business which I ran until 3 years ago when sold it and returned to cl aeros. I am on my 3rd Chippy, again completely redesigned and now sporting Saito engines along with a Novi, Novi 3,od Yak55(flew to Compton Abis mant years ago and saw the first one in the UK.........been a fan ever since) and a brand new close to scale lightweight 55 nearly complete..my engine of choice these days is Saito at all sizes including a 125 for rc,.........that will do for now enjoy the pics.including chippy7 on flight line at 76 WC's.cheers Pete
.......dont use forums very often and have just cocked up the pics......will post seperately.... ???
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From Pete T
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Pete T again
Novi 3 Saito 40.absolute dream
Yak........First interpretation of the 55, newnone on building board closer to scale
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Hello Pete, do you remember flying at Rochester Airport Kent, Elliot Model Engineering Club to be precise? T'was about '74-'75ish, if I remember rightly, you flew a Sabre shaped jet style model, would that be right? I was judging that day. I think you might have won ???. Can't remember who else was flying.
Cheers
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Hi Neville, yes I did fly a Sabre , another foray into semiscale........ started originally by my mentor when I was 13 named Dave Chizlett who came 2nd in the Gold Trophy in 54..........competitors at Rochester would probably have included Jim Manell,Glen Allison, Brian Dyke, John Lynch,Pete Burgess, Keith King............possibly Steve Blake and John Newnham
Pic taken by Jim in Bochum in Germanyabout 74...........only pic I can find including the Sabre..........cheers Pete
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Pete, if I am not mistaken, you are an accomplished RC flyer who specializes in 3D aerobatics?
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Pete,
Thanks for the update on your life in C/L and welcome to Stunt Hangar! I'm astounded I was able to upload a favorite picture from a book published in the UK in the early 70's and not only find someone can identify the pilot, but receive correspondence from the pilot. It makes me realize how much I took the internet for granted.
Doc: You're an absolute Ace!
Ty, Neville: Thanks for the link to the plans.
Now I know what my next build project is going to be. Does anyone happen to have a JVL Chipmunk kit (built-up wing) you don't plan to build and are willing to sell?
H^^
Damian
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Now I know what my next build project is going to be. Does anyone happen to have a JVL Chipmunk kit (built-up wing) you don't plan to build and are willing to sell?
H^^
Damian
You might be in luck. Contact Walter Umland for info.
His website: http://builtrightflyright.com/
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You might be in luck. Contact Walter Umland for info.
His website: http://builtrightflyright.com/
Thanks, Clint. I checked in with him earlier this week - I'm still looking.
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Pete, if I am not mistaken, you are an accomplished RC flyer who specializes in 3D aerobatics?
I wish I was an accomplished 3Der !!!!!!!!!!!!!! however I do, and have for a number of years, flown RC aeros.........my model business produced a small range of 3D machines as well as pattern type which were demo'd at trade shops by a superb team of expert youngsters (compered with me , that is )The Edge is about 3 years old and flown occasionally.......the other is a Smooth Operator which was our biggest selling model........this one powered by a Saito 125............absolutely awesome.cheers Pete
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Is wraping in copper wire and soldering to make my eyelets on my leadout's still a ok way of doing it?
There is absolutely no good reason to avoid soldering here, you just need to know what you are doing.
Many top fliers in Australia silver solder and copper wrap their lead outs with no corrosion, stress riser or strength problems what so ever.
The advantage with 'not' using ready made brass eyelets is that wrapping produces a perfectly circular final wire diameter that can swivel in the line clips without catching anywhere, and that's something a brass eyelet can not lay claim to.
I have heard of fliers checking the orientation of their lines just before take off and then getting airborne only to find that an eyelet that is sitting vertically (or at some angle other than its supposed to be at) in the line clip and suddenly straighten up out under load - and guess what that does for the heart rate!
Cheers.
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(snip)
I have heard of fliers checking the orientation of their lines just before take off and then getting airborne only to find that an eyelet that is sitting vertically (or at some angle other than its supposed to be at) in the line clip and suddenly straighten up out under load - and guess what that does for the heart rate!
Cheers.
HI Chris,
I don't know about "heart rate", but I know you can lose the outboard wing at the bottom of an inside loop when it does occur......... And that was during an official flight..... :o :o
Big Bear