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Chipmunk's for beginners


Dennis Mulhair
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Well its day 2 and I thought I had better make a start before I get so far behind I won’t know what I’m doing. It was a good idea starting a day behind Danny as I can have his blog open whilst I’m putting things together.

Pictures 1&2 are self explanatory but 3 is my attempt at getting the fin post central. I also took Danny’s advice on laminating the fin post from 2 pieces of 1/8 balsa. I will fit the second laminate tomorrow when everything is dry and solid.

By the look of picture 4 it seems to of been a success. I look forward to your comments.

Well that’s all Folks!!

Be sure to follow the next exciting installment.

Dennis

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Looks good so far Dennis. For me this build will be a case of little and as often as you can.

Adding photos is pretty easy once you have them in your album, look out for the camera icon.

Edited By Nev on 03/10/2014 21:12:07

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Hi All,

Its been rather slow progress and I had no problems with the fin but that is where the joy ends!

My main reason behind joining this build was to get help and assistance with something I have never completed before. Seeing that I had all the plans, cowls and canopy it was just too good to be true. Well it seems like I don't have the same plan as the rest of you! My equipment was ordered back in the late 90's and is a Chipmunk 1 and does not have all the extra drawings for the Mk2. See the enclosed photo's and compare to Danny's rudder posted on his blog on the 8/10/14 @ 15:05.

Is it possible to get the missing dimensions to keep in line with everyone else?

I am also having issues around the rudder build. Again from my pictures the ribs from the wood pack are too small and seem to taper from 3/8" to 1/8" between the lower one and the top one. Yet the fin post tapers from 7/8" at the bottom to 9/16" at the top. Are these ribs too thin? Is it best to make new ones of the same thickness of the 1/4" sheet at the front of the rudder?

I think that's it so far!

And finally it seems I can copy the pictures from my album across into this blog using Internet Explorer and not Firefox.

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Hi Dennis, ooo an original Nexus plan. it does look like it has been updated. I would suggest that you make the 1/4 rudder leading edge exactly the same shape as the fin rear post, split it lengthways and remove 1/32 from each side (rudder core will make this back up) And then make triangular ribs that taper from the leading edge to the trailing edge in a straight line. It might be easier.

And don't worry we have all had issues with the thickness of the rudder, it will be the same when it comes to the elevators, don't trust the plan implicitly (I know that goes against the grain)....

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Try using this pic to help work out the shape. If you place an X on your plan by measuring a 30 degree angle up from the rudder horizontal line formed by the underside of the aerodynamic balance. place your rudder core over the plan and rotate about the X, until the distance from the existing outline to the position of the the rotated core is 16.5mm as shown, then draw around the rudder core you will have a new curve, its very close indeed. Hope that kind of makes sense??

Cheers

Danny

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So everyone else is building from the Traplet plans but Dennis M is building from the Nexus ( now MyHobbyStores) plan!

Same designer, same wingspan but different plan services, so is the construction exactly the same?

Presumably if bought in the 1990's then Dennis M is using the Nexus/MyHobbyStores canopy and cowl but the modern Traplet lasercut parts? Will it all fit?

Edited By kc on 10/10/2014 17:35:04

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I would suggest looking carefully to see that the cowl seems like it would fit over the precut engine bulkhead etc. There could be various thicknesses of fibreglass used by different manufacturers, maybe different attachment points etc. Quite easy to modify a bulkhead at an early stage, much more difficult later. Horrible job to hack a nice cowl around to fit!

Canopies are usually trimmed to fit so that might be OK. Presumably you would just follow how the laser cut parts fit even if the plan differs so that wont present a problem. Good luck!

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  • 4 weeks later...

Hi Dennis I glued the fin part of the hinge but not the rudder. Not sure I have done right though as the rudder part will have to be covered before fitting so access to the hinge for gluing may be awkward. However you will not get access to the nuts to assemble the hinges the other way, and you don't want the fins glass work to get into the hinges.....

Cheers

Danny

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  • 2 weeks later...

Hi All,

Finally managed to make a start on the tailplane. I followed Danny's initial build on page 4 & 5 of the "Poor Mans Spitty" blog. I've completed the bottom sheet stage, the next is the hindges and elevator. I think its straight and if its not its not fat out. If there is a discrepancy could I cleare it by damping the sheeting down and clamping it straight?

Danny what do you think?

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