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Old Aug 09, 2013, 03:23 AM
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Painting and finishing

Now is a good time to add the landing gear fairings and make the last bend in the LG wire if you have not done so already. The LG simply threads through the front flute of the fairing. Do not glue the fairing to the fuselage just leave it free to move about. I have found that the impact on landing damages the fairing if it is fixed to the fuselage.

If you have decided to paint the plane (you will add about 25g if you paint the entire airframe), first tape any areas not to be painted e.g. bars in windscreen. I find that the Rustoleum spray can adheres better to correx than many other paints. I also give the correx a wipe down with paint thinners before painting to remove any greasy finger marks etc.

I paint any foam parts with WBPU and/or acrylic before spray painting. This serves two purposes first, it makes it easier to sand the foam smooth, and second, it protects the foam from the solvents in the spray paint. Many of the foamies folk also add talcum powder to the WBPU to give a smoother finish.

I suggest that adding the windscreen after painting. Make a paper template before cutting from scrap acetate (I got mine from some packaging). Glue on with UHU Por or similar clear adhesive.

Lastly, add any trims that you may fancy.
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Old Aug 09, 2013, 03:51 AM
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Video

Right, now you are ready to fly. Take the first few flights carefully. Wait for a windless day. Note that the curved plate airfoil has a tendency to balloon if the trim and downthrust are not correct, so take your time to get these right before attempting more aggressive manoeuvres. The plane should take off from the ground in a few meters at less than 2/3rd throttle. Extend the TO roll until you are sure your trims are correct and the plane won't try to climb abruptly. Landings are easy, but it does help to keep a touch of throttle until you are on the ground.

Note on throws: The rudder throw should be the maximum possible – i.e. at full throw the rudder should almost touch the elevator. Elevator throw should be about 25mm (1”) each way. Use dual rates if you don’t like sensitive controls – you will need the full rudder movement at low speeds.

Here is a short video of some gentle flying.

Cub video (2 min 4 sec)
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Last edited by Extreme Sports; Aug 09, 2013 at 07:29 AM.
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Old Sep 11, 2013, 01:38 AM
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One of the coolest projects i've ever seen. Have to start building at once
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Old Sep 12, 2013, 07:46 AM
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Great, enjoy. I need to get mine out again - its been a bit too windy recently and I've been testing some other concepts on the windless days

What motor/prop/lipo compo do you have in mind? Mine seems to fly best with the 1550KV EMax CF2812 paired with a 2S 1300mAh Lipo and a 9x6 prop.
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Old Sep 21, 2013, 10:38 AM
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is the auv including the electronics could you please pm me the power combo used or a similiar power combo from hobbyking
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Old Sep 23, 2013, 09:26 AM
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Quote:
Originally Posted by rcniteshrc View Post
is the auv including the electronics could you please pm me the power combo used or a similiar power combo from hobbyking
Yup, AUW includes everything.

The power combination I used is as follows (all from Hobbyking):
Motor: E-Max CF2812 (http://hobbyking.com/hobbyking/store...er_1534kv.html)
ESC: Any 20A or bigger ESC will do the job. I am using this one: http://hobbyking.com/hobbyking/store...rammable_.html
Lipo: I found that a 2S 1300mAh Lipo with a 9x6 prop (I think I am using a Tower Pro one) works very well with this motor. I also tried a 7x6 on 3S, but that was a bit more lively than I wanted with this particular plane.
Prop: As above with a collet adaptor

There are sure to be many other combinations that can work - e.g. Use the lower KV E-Max motor (1200) and a 800mAh 3S Lipo with a 8x4 prop....or maybe even try one size smaller (I don't think I have ever used full throttle)...HK has lots of options.
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Old Sep 23, 2013, 09:46 AM
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Cub as a trainer

This question was asked on a different thread in this forum; best that my thoughts are recorded here.

My first reaction is that this is probably as good as any SPAD plane to use as a trainer, but would recommend adding some dihedral to make the rudder more effective and add more stability. Its advantage is relatively simple construction, light weight and slow flying speed (which of course implies that it will not be the best plane for windy conditions...but your very first flights should all be on windless days, so I don't see this as a major drawback).

That said, I think there are better options for a first plane, particularly if you don't have access to an experienced pilot to help you set up the plane and assist with the first few flights. Crashes are a 100% certainty if you are teaching yourself and its seems a shame to crumple something that actually looks like a real plane and has taken some time and effort to build. Also, the cub is quite sensitive to the initial set up (esp thrust angle) and without expert help, you are almost certain to write off the plane before you get it set up right (or at best you won't know if the problem is with your flying skill or with the set up and by the time you work it out, the plane will have so many repairs that it probably won't look like a Cub anymore!).

My advice would be to look at the foamies forum and build one of the very quick and easy to build trainers there that would run on a the same power set-up (e.g. a slightly enlarged BlueBaby). Alternatively buy one of the small, cheap RTF trainers (e.g Skysurfer....but there are tons of similar designs) and take all the hard knocks on that. When you feel confident that you can fly consistently and smoothly without crashing, then perhaps look at a SPAD trainer such as this one (or any of the others mentioned in the other post - you will be in a better position to decide for yourself which one will best suit you - every poster will have his/her favourites).
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Old Sep 23, 2013, 10:29 AM
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thanks extreme sports for your reply
but one of the main problem I face is availability so it becomes tough for me to build a foamie coro is easily available, cheaper, and easy to make so want to build a spad can you please mention a spad which is durable and a trainer
don't want to go the rtf way as I pretty much dislike it as you don't learn anything how to stuff from that

btw thanks
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Old Sep 23, 2013, 11:36 AM
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Thought foam availability or cost could be an issue - its the main reason why I do so much of my building with correx. I don't have any experience with the other correx 'trainer's suggested as they are larger and heavier than I choose to fly in the nearby park, so I cannot comment on them. I also prefer small and lightweight, but there is a respected school of thought that larger planes are easier to learn on.

Two suggestions:

1) Make a corro-cub, but simplify the fuselage and certainly don't worry about windows, paint, wheels, nose cowl etc. Maybe enlarge the rudder slightly. Definitely use a prop saver to attach the propeller. Add 1 washer of right thrust. Put in about 75mm of dihedral measured at the wing tip. Once you have learned to fly and its looking really ugly, build a nice new one with all the trimmings.

2) Enlarge the Blue-Baby plans to say 40" and build it from a mix of correx and polystyrene offcuts from packaging (use the polystyrene for the mono-block). It won't be as light as the all foam one, but I am sure it will still be a good first plane.
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Last edited by Extreme Sports; Sep 23, 2013 at 12:03 PM.
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Old Sep 23, 2013, 12:18 PM
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thanks for your reply will try doing the 2nd one or go the avispad way as the 1st one is tough to do.
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Old Nov 08, 2013, 02:50 AM
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Modification: Add dihedral

Finally got round to adding some dihedral. This significantly improves easy of flying. Without the dihedral the plane had a tendency to side-slip and nose-up in turns and rudder sensitivity was not well harmonised with elevator sensitivity. With the dihedral, turns are now totally predictable and overall flight is more stable.

I'd suggest adding 50mm (2") - measured at the wingtip, with one wing flat on the building board. The easiest is to build the wing as normal, but before gluing the bottom centre section in place, snip the CF spar in the middle and cut a shaped slit in the centre of the top wing skin. The slit should run from 2 flutes behind the LE to 2 flutes in front of the TE and be slightly wider in the middle. DO NOT cut the CF rod in the front flute (this way the wing will stay joined and is less likely to twist; the CF rod will bow to match the dihedral). Glue the spar back together with the desired dihedral using a ply brace on either side. Use hot glue to tack closed the joint in the slit you cut in the top correx skin. Finally, glue the bottom centre section on, and wrap the whole centre section with strapping tape or duct tape.

I would go so far as to say that with this modification the plane would probably make a reasonably good lightweight correx trainer.
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Old Nov 08, 2013, 03:52 AM
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If it realy makes a better trainer I will add a 3" dihideral in it that would make it more stable
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