Mr Cox

I have just finished another "stick" build and though I would share a few images here.
This is a swedish laser-cut kit called "ZIPP" and it is meant for electric motors, but they are simply too boring (to me). The design comes from a .10 fun-pylon class though so I though I would simply put a .10 engine in it. The structure is quite light so I have decided on an OS .10FSR engine, which is lighter than the .10FP while still being close in power. They both make around 15800rpm on an APC 7x4 and 10% nitro (stock mufflers and carbs on both).

I was also tempted to use an Enya .11CX, but it didn't quite fit in between the fuselage sides without larger mods. Might still go that route if the OS is not powerful enough.

Below are some data, and pictures, I'm particularly happy with the overall weight, I have flow heavier planes with a Babe Bee in the front...
(Complete build thread in swedish here; http://www.svensktmodellflyg.se/foru...1&replypage=99 )

Wing span; 33"
Wing area; about 260 inch^2
Total weight; 18.7 oz

combatpigg

My Feedback: (3)

Nicely done Mr. Cox...!
That's a great looking kit, I hope the manufacturer sells a million of them.

Pond Skipper

Great job on the flame work and extra effort with the red trim pops. The transparent blue shows off all detailed laser work well.
Should float in at 18.7oz / how many oz torque does the elevator servo have?
With the low weight the APC 7x4 will fly the plane straight up at 75+ kph. Post a flight vid if you can.

aspeed

Nice, like the drug store gas tank, and it must be light as the batteries are way back. Google translate works well to get the basic idea of what is being said.

Mr Cox

Thanks for the compliments on the covering scheme, that is still the most difficult/nervous part in a build to me, I find it very hard to visualize what colors that will work and what will not...

The elevator servo is a GWS naro (14g) with a torque rating of 1.8kg. I haven't used them before so I really don't know how they will hold up. Seem a bit sluggish to me in the movement, but on the positive side there is no jitter.

In the wing I have put two HS-45HB, they have such long cables that they can reach the receiver without extensions and gives the possibility for flaperon set-up too.

I prepared it for a landing gear too, with racing wheels, but it turned out a bit heavy. An extra 3oz weight just to have the landing gear on seems a bit too much.

MJD

My Feedback: (1)

I'm looking forward to trying out the HS45HB's as aileron servos on something soon. To me most of these small servos have plenty of torque, it is the robustness of the gear train that makes or breaks the deal. Ther 45's look like they have a good gear train.

As an example, using the online servo force guesstimator, a Screamin Demon at 175 mph needs about 47-50 oz-in torque. I think 10-15 oz-in is plenty for half-A's, if the servo is well built.

260 square inches should be nice and floaty while also being sporty. Bet it's a fun sport model.

You can get CF 1/2A proto speed LG struts from Eliminator, and add light wheels. Very light gear. The struts bolt/epoxy to a vertical flat surface, as in a profile fuselage or box fuselage side.

http://eliminatorprops.com/store/ind...&products_id=8

A bit short for a .10 I guess. I bonded a pair into the ACE wing on my Squirt, and it looks kewl.

Mr Cox

I made some 2" racing wheels and an aluminum landing gear now, with a weight of 34g (1.2oz).
So the total weight now, including landing gear, is just shy of 20oz and it should still do well on a .10 engine I think.

combatpigg

My Feedback: (3)

Nicely done..!
This model reminds me of the Midwest Aerosport series. I think it was the only model I've flown with the rudder hinge line tilted back.

Pond Skipper

Wow from 3oz to 1.2oz big drop in weight! Really looks much better with a landing gear ---- and the crowd chants vid vid vid
So was it a combo of wheels and the thickness of the original landing gear that saved weight with the new set up?

MJD

My Feedback: (1)

I had read or heard somewhere that around 30 degrees of sweepback, on a typically proportioned model of this general layout, is about right to make level turns on rudder only.

combatpigg

My Feedback: (3)

This might mean that a commercial design was actually test flown, then sent back for a rudder tweak, then test flown again before sending it into production...?
The next thing you know, someone will report that they know of a commercial design that was actually test flown on the entire size range of engines that are listed on the box...!

lightface79

Where did you by this kit?

Mvh Janne

Mr Cox

I think I bought it from rcflight.se (it's 2 or 3 years ago) but they seem to be out of stock now.
You might be able to get just the drawing from here; http://www.modellproduktion.se/
That would be the older version with balsa fuselage rather than laser cut lightply.

There is also the original "Sting" which you can find a drawing for in modellflygnytt (in the mid 80-ties I think).

I have an old beaten up version of the Sting too (see below, with the ASP .12 engine) it has a slightly larger wing and I have used as a testbed for .10-.12 engines. It is much heavier though (around 700g-750g I think) but it really woke up when I put a .15 engine in it, but now it needs a lot of rubber bands on the wing...

They didn't come with rudder, and I haven't made any rudder on the ZIPP (yet). So the landing gear is more for saving props on landing than for taxiing around.

On the Sting, the angled rudder seemed to affect the knife edge flight, or perhaps I just need to practice more...