600 Series Piper Super Cub 95

[Phugoid]

The side view on the plan clearly shows about 1" of Dihedral, and Kittyfritters example has some, and yet there is no instruction to tilt the root rib, am I missing something?

If there isn't any given I'll make up a templte to set the rib root for 1", but I thought I'd ask to see if anyone knows first.

[Phugoid]

After my summer hols I started to work on the wings. Mocking up the parts revealed a number of fit problems with the parts in addition to the leading and trailing edges previously mentioned. For instance the F1 formers do not fit in the gap thus:



but the other formers fit fine:



The wing tip parts don't meet neatly:



And the last former (F4) does not sit down onto the leading or trailing edges properly



Also the die cut slots for the spars is at least 50% too big making a sloppy fit and a potentially week joint.

[Phugoid]

or perhaps a weak joint!!!!

I decided to infill the slots an remake them in the right size. I did this with balsa scraps:



I them sanded these little bits back to the profile before re slotting them at the correct width, depth and position:





You may also have noticed that I have filled in the slots in former F3 for the wing struts, this is because I think that these are more likely to hinder rather than help neat and strong attachment of these parts.....

[Phugoid]

Here is the final assembly being glued up. I "cracked" and re-joined the top spar at both the final F2 position and the F4 position (only the join at F4 is indicated on the plan):



Here's the final construction after a bit of a trim and an initial shaping of the tips etc:



More likley than not I will add some corner gussets made from scrap at the root end. These do add a lot of strength for very little weight penalty and also help prevent wrinkles when the wing is finally covered.

[Phugoid]

This shot clearly shows the angle of the root rib to give me the 1" dihedral that I mentioned:

[Noobrider]

where did you get those pins from?

[Phugoid]

From a supplier called SAMS in the UK, but they are made by Peck Polymers in the US:

http://www.a2zcorp.us/store/Category.asp?Cguid={1CEAFAEA-3516-4E2C-810E-72861C81E424}&Category=ModelTools%3APins

[Phugoid]

Most of the construction complete, begining to look like an aircraft

[lukebozek1]

This looks great! Very nice, clean and the kit seems pretty robust. How was cutting the diecut pieces? Keep it going!

[Phugoid]

The actual part cutting out was not too bad as the die cutting was reasonably neat with not too much crushing, and the sheet would was nice and light. When it came to assembly the notches in many of the parts being grossly oversized was very annoying and time consuming to correct. I still maintain that Guillows would be better off providing accurate print wood rather than damaged and inacurate die cuts.

The strip wood is very heavy and I think that the AUW will be in the area of 35-38g dependant on whether I decide to paint her. This is largely to the weight of the said stripwood in the wings.

Having said that I think that with some decent rubber some nice 30s flights should easily be possible, and it should survive being tossed into the air by my 5 1/2 year old daughter!

[scigs30]

I would agree 100 percent that Guillows would be better off supplying quality print wood vs inaccurate die crushed wood. I sand most of the parts to get a tight accurate fit and this takes care of 90 percent of the problem. If the gaps are too big, I glue the part into place and at the same time glue a wood shim to fill the gap. As far as the wing tips or any curved parts go, I glue them together first and let them dry. Then I remove the tips or curved parts from the plans and sand nice and even with dowel wrapped with sand paper. Then I place the parts back on the plan and add everything.
By the way, Great build.

[Phugoid]

Thanks Scigs.....

I have tried thus far to stick with the plans and the contents of the kit not only out of curiosity to see if this kit will fly "as standard" but hopefully to help anyone new trying to build the kit as a first off attempt . I have abondoned this slightly in the fact that I won't be using the kit tissue or rubber, the first purely for aesthetics and the second because I know the guillows rubber won't give me much more than a short hop in the air (if that!)

With this in mind I moved on to complete the fuselage. The plan calls up for the nose to be covered with tissue. Generally I would ignore this and "plank" the nose at least in part, since the added weight will be required anyhow and the model is less prone to damage when handling/winding etc. This also means that the nose can be nicely rounded and not be a series of flats.

However I realise that this requires a stock of balsa which is not readily available to all so I've decided that a good compromise would be to use printer paper to cover the nose. This can be curved to follow the profile (at the top at least) and add a little more strength that using tissue.

Firstly I did the bottom in three strips as there is a compound curve, the steps between each piece won't look so bad when finished as I will sand them with 1000 grade paper prior to paint which will reduce the step a bit.





Then the top which was easier and was done in one piece, one other point to note is that I removed the 1/16" cross brace on the nose as I felt that it might get in the way of the prop hook/rubber and I thought that the rest of the structure and the paper would be rigid enough (sorry i forgot to take a picture of that bit)

[ADW 123]

whats the best way to avoid wrinkling on the front parts of the wing. ive always had problems with that esp. on those smaller series with the 1/32" balsa.

[Phugoid]

The balsa ribs are not quite as thin as the 1/32, think the stock was around 1/22" or 1/20", but it is certainly thinner than the 1/16" that I'm used to. So I am slightly concened that when the tissue shrinks spanwise the root rib will deflect and I will get stress wrinkles running parallel to the root rib, especially since I'm going to use Esaki tissue which shrinks a lot.

I don't think I'll have the same problem (stress wrinkles) with the leading edges as the strip is so hard and rigid.

In the build thread I mentioned additional corner gussets at the wing root. These should hopefully prevent this distortion and they also stop the tissue "dipping" at the root when I glue it to the frame, which normally results in a wrinkle later.

Andrew

[ADW 123]

yeah but i always get stress wrinkles just on the leading edge on the curve.