KK Piper Super Cruiser Build

I thought for 2018 I'd have another go at indoor flying, After my first attempt at the indoor Nat's with an untested model that seemed determined to batter itself to death on the floor I thought I'd start early this year

I will the even try the unconventional method of trimming it first

This time I have opted for a safer bet with the model and gone for a nice high wing monoplane. The 130% KK Piper Family Cruiser for CO2 is such a nice flyer I though I'd give its stable mate a go the Super Cruiser. This will be my first go at a rubber powered model since I was a kid . I even found a nice easy colour scheme on the web to build it too and Piper's always look good in yellow




Fuselage sides are fairly straight forward, though as there are no square sections in this one a bit trickier than usual.




The only square-ish bit is the centre section so I started with that





The formers then help form the shape of the fuselage




Wings are about as straight forward as you can without cuting them out of sheet







I did start this a few days ago I can't really build this fast !

What another nice project sir.
i expect it might fly if you trim it first. (never catch on though)

Tony B

Looks good. Should be a good flier.

One observation. I couldn't really tell whether or not this is scaled up. If it is I don't believe that it would qualify for the indoor Nats. I believe that in outdoor kit scale scaling up is acceptable, but for indoor not.

Sorry to be Mr. Gloomy, but it might be worth checking out the rules at this stage rather than later if kit scale is your intention, but applogies if my eyeball is out on the scale, the 30% extra is quite hard to spot in the pics

Andrew

Thanks both

Andrew - This one is the original size so 18" span... and yes I may give Kit Scale another go too

Ahh, great stuff, glad to hear it! Will watch with interest!

Andrew

I'm following the thread with interest, boz.

Andrew Darby wrote: ..... I couldn't really tell whether or not this is scaled up. If it is I don't believe that it would qualify for the indoor Nats. I believe that in outdoor kit scale scaling up is acceptable, but for indoor not..... Andrew

Andrew's quite correct, models for BMFA Kit Scale Indoors are not allowed to be scaled, but models for BMFA Kit Scale outdoors are!

A bit more progress on the Piper ...

A fin and tailplane




And an undercarriage and tail skid




Almost an airframe , just need to sort out he nose

Nose section added today






I wasn't quite sure how to do the nose block not having done one in a while but after some much needed advice ..... I went for a lamination of 1/32 ply 1/8" balsa and a bit of 1/64 ply, hopefully I can cram a KP adjustable nose bearing in there









While the glue dries I made up a pattern for the cowling in paper. The finished one will be in Yellow paper that's a close match for the Esaki tissue I have to cover it. I can't remember which glue I used on the larger Piper so the glue doesn't show on the paper ... I think it must be canopy glue. I tried doping some paper as the KK instructions say but that has turned to a streaky mess so I'll abandon that method.

I've only painted the front former and dash , I'll leave the rear formers in balsa, they will be visible through the windows but they will be under the wing so less obvious.

It's time to cover the airframe so I thought I'd give my easy method of tissue covering ( other methods may vary ) which is mostly based on Andy's articles in AM. I friend of mine is building his first indoor model in 20 years so I said I would give some pointers

First I lightly sanded the airframe with 400 paper to get rid of any balsa fuzz.
For covering I used Esaki Tissue and tissue paste and some 50/50 cellulose dope for the compound curved bits though Ezy-dope will probably work as well

Flat surfaces are the easiest so I started with those. Some tissue paste was applied to the tail around the edge and along the hinge line and spread with a finger. The tail was then placed glue side down on a piece of tissue, shiny side down held taught on a flat surface. I then turned it over a smoothed out any wrinkles are left it to dry.






When it was dry I trimmed the tissue with a scalpel to 1/8" or so from the frame and added some cuts to aid the fitted around the tight curves






I then used a small amount of tissue paste to stick the overlap to the frame and then left it dry






Tissue paste was applied to other side of the tail/fin being covered and the process above repeated applying the part to some tissue on a flat surface and then left it dry





When it was dry this time I cut the tissue as close as I could to to the edge of the part without nicking the edge and sealed it which a thin wipe of tissue paste.

The curved section of the top wing is a bit trickier but having covered the underside first tissue paste was applied to the vertical edge of the wing along the LE , TE and wing tip and along the root rib top . I stick the tissue to the ribs too as it adds strength and in the event of damage makes its easier to repair a wing bay. The tissue had plenty to spare around the edge to make life easier, I smoothed out the wrinkles best I could trying to keep the tension even and left it to dry






When it had dried I carefully trimmed away the excess tissue with scalpel and sealed the edge with a light smear of tissue paste





For compound curves I use a different approach and use the Esaki tissue wet. Cheaper tissue has little wet strength so this only really works using the stuff.
For the nose block I applied a couple of coats of sanding sealer first then a coat of 50/50 cellulose dope. I sprayed a small piece of tissue with a pump sprayer and let it soak in then applied it to the doped nose block . Working from the flat centre gradually work out , smoothing the wrinkles as you go. once your happy leave it dry and trim the excess of when its dry






Once the tissue paste was dry I gave a spray with a plant sprayer and stood it upright for the real wetness to dry off then





When it was nearly dry I pinned it flat left it overnight . 1/16" of washout added to the wing tips

A cowl has been added as per the KK plan form yellow paper and cabin glazing from .25 acetate sheet.
It was taped in place and the a bead of canopy glue applied to the edge. I'll stick the top edge down once the bottom edge had thoroughly dried




Once the glue had dried I added the side panel in tissue and some glazing bars of tissue stuck on with tissue paste

After drying overnight the wings and tail were given a coat of 70/30 Non Shrinking dope




A bit more yellow paper for the undercarriage and trim added in black tissue




All I need to do now is stick it together and make some struts .... and sort out the prop assembly.. and add the top to the canopy ...well it's nearly finished

Hopefully it will do the job intended

That is looking super good

Stuck the bits together today .

I've left the tail loose in the slot but with a bit of 1/16" sq holding it in place at the front edge so I can adjust the incidence with a scalpel and some packing if necessary when trimming

The required dihedral was added as the wings were stuck to the fuselage. Unusually in the this model the wing roots are 90 deg while the dihedral angle is built into the formers and wing root rib in the fuselage construction... worth paying attention too when you build the fuselage




Almost there in just about a week. I don't have prop or nose button yet , just about to order from SAMS, so just the 'v' struts to add to the main struts and the fin reg number. I assume there was a wing reg too but as its kit scale and you can't see it in my ref photo I don't have to do it ...I think

Finished it !!!





...Well apart from the prop and nose bearing. Next stage is to see if it will fly but I'll have to wait for a suitable indoor event to try it out.... Hopefully the next P'boro event

AUW ,obviously minus the prop, is just under 20g which sounds good to me for an 18" span, but what do I know and I haven't balanced it yet. I was going to set the CG so it balances on the wing spar or maybe a tad in front as seems usual with these designs ????