Kymbo's Ozprey build

[kymbo]

Picked up a bare bones kit from Gerard on the weekend and have made a start. The costs sure do build up quick when you need to start buying the bits and pieces.

So far its cost
$75 for the Ozprey
$39 for the 10mm round spar
$20 for the 77 spray adhesive
$ 8 for the filament tape
$15 for the aquadhere
$10 for the control rods

Still fairly cheap for the fun I am expecting to get out of it though.

My aim is to get something a bit faster and heavier than my bee, after a sniff of this DS ing stuff you guys are getting up my mind is running wild.

I also am thinking about building an alternate fuselage to use as a test bed as I start to dabble in the world of brushless motors and lipo batteries.

[kymbo]

So far I have glued in the main spar and started doing experiments with spackle. Ive been asking peoples advice from time to time and as you would expect opinions differ a great deal. Originally I didn't intend to spackle the plane as I was concerned it would take away some of the epp's elastic properties. Yesterday I was told that it was a good idea as the ozpreys wings are of cut foam the surface is very porous and the tape has difficulty adhering to it even with the 77 spray.

What Ive done is using a piece of epp offcut is to mark out 4 sections, spackle with 77, just spackle, just 77 and nothing. I will let the spackle dry and then stick some tape on each section to see how much they vary.

I'm not trying to build the worlds most perfect plane but I am trying to learn with the least amount of mistakes possible and avoid the "You should have done this" so anyones opinions would be greatly appreciated. Geeeee balsa is different

[windsock]

Will be interesting to see how your spackle test goes. I have one spackle OzPrey but two that aren't. No big difference in the quality of covering that I found. I did however completely cover the wing with reinforcing tape before placing coloured tape over it.

Gerard

[thevon]

Kymbo, that's really great that you're doing some experiments. Can I suggest a couple of things??

1) Have a look at this thread - it discusses some of this.
windsock.proboards76.com/index.cgi?board=techaerotalk&action=display&thread=386&page=2

It's also been discussed in Windsock in other places. However there were several huuuuge threads in RC Groups also - information overload.

2) I strongly suggest that if you're gonna use spackle, mix about 1:6 of PU glue with it. Otherwise it just crumbles up on impacts.

3) Unfortunately I've really lost confidence in Super 77 for long term durability. Compared to Goop, it's poor.

4) All of us who've tried Gooping will resoundingly tell you - you must use it! It's fantastic!

5) The final point is ... my Ozprey is covered in 80 micron laminating film, and truly, it's the way to go. You'll cover it faster than a tape job, and it's heaps more durable, and it flies slick like a moldie. Plus, you don't really need to use any spackle under it either.

In summary I recommend just putting a couple of coats of thinned Goop over the whole wing, then covering it with film - elevons and all. The Goop makes the film stick better and gives the foam protection against heat from the iron. When you're finished get some fluoro vinyl and put some on the tips, and make a few more patterns with foamie tape as well. Dead set, you'll be happy, the plane will last much longer, and when you re-cover it the film will rip off easily and you'll find the wing is in excellent condition and you just re-cover with film. Nothing like it, I reckon.

[chamm37]

Yer well that is what i am going to be doing with my Ozprey Andrew....just ordering some of the micron film today and i should be able to complete by the second week of holis(going to mums in the first week....no building )

But i tell ya Kymbo Andrews Ozprey flyies so nice and man is that thing quick

[kymbo]

Well I meant to make a start on it yesterday but the distractions came thick and fast. I did manage to do the epp adhesian test and yes most off what I was trying to find out was on that link you posted Thevon.

I found the super 77 increased the adhesian of the tape 10 fold and the combination with spackle and 77 gave it another 20 percent. The spackle mixed with the PU did produce an unexpected result for me in that the strength and lightness of the end product where incredible but still....

I spent some time thinking about what I wanted from the plane and factoring all the other information about glues, coverings and modifications and decided to do it all by the "manufacturers" instructions and build it in 1 day.

[kymbo]

I started on the Ozprey this morning around 10 after taking the dog for a walk. I got about an hour into it when my daughter called me for a talk. That went for about an hour and half with me using spray adhesive without her knowing.

All went pretty textbook with a few minor variations from Gerard's instructions. I decided to leave the spackle out of the equation and I ran the servo wires forward on an angle so that they would enter the fuselage in the receiver bay.

I got a little artistic with the colour tape and the only major problem I had was tearing the epp beside the fuselage when I was trying to remove the cut out for the battery.

When came 4 oclock a quick look at the windreport showed that a Northeasterly was pumping so I had to abandon the project to take the Bee out for a few laps.

All that remains is to fit the control rods and horns and balance the centre of gravity. I'm not happy with switch charge set up and am considering a lost model alarm.

I'll email some picks to Gerard and maybe he can stick them up for me. ;D

[thevon]

Way to go Kymbo. All of the more complicated building stuff is OK if you have the time, but the most important thing is to get out flying, hey! Looking forward to hearing how you like it.

[windsock]

Here's Kym's build of his OzPrey. Awesome tape job.

Gerard

[kymbo]

Well control horns and rods weren't a problem and it only took 48grams to get the CG right. I made a hatch to access the radio gear with some corflu and velcro.

I've set up the dual rates and exponential as per Gerards recommendations with the exception of 25% on the elevator. I need at least 40% to recklessly pull the nose up as I over correct due to my limited flying abilities

Strong South Easterly predicted for Wednesday arvo. Will aim to maiden it around 4pm at SC

[kymbo]

Well that was largly unsuccessful. The wind was gusty from the South and had hardly any lift. I took my bee up first to check things out and had a hard time finding any flyable air. I tried some glides down the grassed hill by cabbage tree creek and found the Ozprey to be very twitchy. She wanted to go staight up or straight down and didn't respond to inputs very well.

I turned the rates off to give me half a chance and sent her over the edge. Did some wonderful stunts I have never tried before until she plummeted into the ground busting up the battery pack.

Summary; move the cg forward and buy a new battery pack and try again this weekend.

[kymbo]

Well to my surprise a strong Sth Easterly came up this arvo so I through the Ozprey in the car and headed down to the Southern end of SC.

I did a couple test glides which seemed reasonable then took it up to the cliff edge and shot it out. A bit of fiddling with the trim and she was away.

I am rapped. Its exactly what I was hoping for being twice as fast as the bee and much more flight than kite characteristics. Its speed, penetration and manouvarability surpassed my expectations.
www.youtube.com/watch?v=_NUQzeM_NwQ

[felix]

That thing looks great and looks like she is seriously quick! top job. Think I need to stop trying to make bees go fast and get one of these lol……that lift looks awesome too,wish I could have made it out this arvo.

[nige]

Great looking plane kymbo, I'm not surprised you like it. I have had mine for a while now and I just love it. You find that it flies in light lift as well. I don't know why all you guys don't have one.
It will fly in really light lift up to 30 knots and probably more.
Felix you will have to start the ball rolling and start a Ozprey revolution.
Disclaimer ( I am in no way affiliated, paid or sponsored by the aforementioned model)

I just love my plane

[thevon]

This makes me feel like I'm not so mad after all. I think the Ozprey is a really special little plane.