303 piper super cub 95

[jim]

hey guys just finishing up my cub was a lovly little plane to build and hopefully my first flyer
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http://i991.photobucket.com/albums/af37 ... se/017.jpg

[jim]

[jim]

needs 10grams on the nose and im thinking of using a bigger prop one from a 400 serese kit 6" i think after reading it here.i will prep it ready just using kit rubber lubed with a sylicone spray i can get 200 turns quite easy had been to windy to take it out:(

should there be any slack in the motor ive set the rubber length from the peg to the prop wire to be just so the prop cant fall out any tips be great

[Phugoid]

Hi,

Very Nice job indeed, looks really neat both in terms of construction and covering.

A couple of tips:

I'd throw away the white rubber in the kit, it is seriously poor stuff. Buy some decent stuff from SAMS in the uk, the 200 winds will change to 800 with decent rubber.

Also put the knot at the rear peg.......

You can get the rubber a couple of times (and more) the prop to hook length, only the last 50 winds or so will let it go slack and result in the prop falling out. This generally acts as a nice mechanism to stop it going OOS. If you don't want the prop to fall out and spoil the glide then you can braid the motor, there's plenty of good info on doing this in Don Ross's book or on the internet.

Andrew

[jim]

heya thanks for the tips:) im having trouble on what size rubber to buy and advice would be great this is what im looking at
[url]http://www.samsmodels.com/acatalog/F1._Rubber_Strip.html[/url
*scratches head bemused*
i knotted the rubber at the rear peg and used a small offcut to secure it to the prop wire
ill co check out this braiding sound's interesting:) thank's again jim

[jim]

http://www.samsmodels.com/acatalog/F1._Rubber_Strip.html

[Phugoid]

Jim,

Send me a PM with your full name and address on and I'll pop you a couple of sample pieces of different rubber strip that are likely to suit in the post FOC.

For a Kick off I reckon we'd be looking at a 1/4" strip for this model with a single loop, but the supplied prop is smaller than I'd naturally go for a 24" span model (try the 6" prop if you can) so nothing is definite!. Initially I'd make the motor just a bit longer than the prop hook to peg length, you can make up longer motors later. Incidentaly 1/4" is a wide as it goes, so if more power is required then you have to start looking at multiple strands (ie loops) of smaller width rubber.....

What is the AUW (less rubber) of your model?, and the approx prop hook to peg distance?

The truth is that you never quite know exactly what motor width (the thickess is always the same) you need until you have a go due to the variables of weight, prop size, and trim.

One thing do you have a winder? Putting 800 winds on by hand would be tedious to say the least and also you can't stretch whilst winding (this allows more winds to be put in a set length of rubber) This means that you can't retain the rubber on the prop hook as you have suggested because you need to be able to take it off for winding.

Here is the one i've got, you can get it from SAMS or KP aero direct:

http://www.kpaero.com/ProductReport.asp ... ry1=rubber

This is a snip at £7.95!

Andrew

[jim]

hey andrew thanks for your offer it's very kind of you offer some of your own supply of rubber.having reading i can get prob 400 ish turn's in the motor i became aware my little finger couldnt spinn that prop so many times hehe i heard of winders so i will order one allong with my rubber i dont mind paying.guess i will need some good quality lube too i saw a post where a prop wire was made with a loop to take a winder can these be bought or are they generally made
maybee i can buy a mixed lot of rubber and make a few prop's up to experiment with
thank's again jim

[scigs30]

Your Cub looks great. Definatley buy some good quality rubber and a winder. This is a great flyer with a little down thrust and clay in the nose.

[jim]

wow scigs that looks amazing i ordered up some rubber cant wait
i have allot of admaration for your work ive never seen models so well built i followed a couple of your post's aspiring to learn:))

[jim]

weather was good finally at the weekend managed to go out and see what would happen on test flying....i lost a wing:( glued back on now and ready to go again on the next fine day we have:)

could use some trimming tips launch saw her fly forward a meter or 2 up on to her back and nose diving the vertical impact shocked a wing off:( i do admit the joint wasnt so good im guessing i got the balance off a bit and need some more weight in the nose
do i somehow need to bend the tailplane down?
dose the tab u place on the wing make a reall difference to counter the motor i didnt have one fitted
i read allot of you guys use downthrust on the prop and washout on the trailing edges of the wings im a bit clueless as to what effect this causes on the plane

any advice welcomed

[scigs30]

Jim, there are so many possibilities and the trim tab I use is not really necessary. Trimming is a finicky part of these planes and for the most part, Guillows models are hard to trim. For flying model planes I highly recommend " Peanut Power" by Bill Hannan. It is an old book but I still do all my flying based on the theories in that back.....When you start reading it, you will see were I get most of my tricks. Try not spend too much money on it, search around.

[Phugoid]

Ah trimming.......

This is the most chalenging part of the hobby really.....

Take one step at a time with it, getting a nice controlled hop is the first thing to do before worrying too much about

First use a rubber motor that is just the prop to hook length, there are then no issues of shifting balance. You can always experiment with longer motors later

Test glide to get the balance first, I initially I do this from the corner of our bedroom door onto the bed, and then move onto a field with long grass (or the back lawn if I've been lazy!) You are looking for a nice steady downward path.

I always start with a bit of downthrust and right thrust. The down thrust prevents the nose from rising under the initial burst that the rubber gives, this can look like a stall. If your plane glides nicely then noses up under power then it needs the down thrust to keep the nose in check.

The right thrust counteracts the torque of the prop, I would go without any intially to set what happens, it can if things stack up right for you it can induce a nice turn and stop your model from flying away in a straight line.

The washout is a way of stablising as it makes it so the tips stall last making it stable. With a high wing design like the cub you can get away with out it, especially since the design has some Dihedral too.

In summary get the glide right first then gradually build from there...

Andrew

[jim]

thanks guys:)