Keil Kraft Skystreak 26 foam build

[baz49exe]

Way back in 1960 when I was 11 years old I built my first model plane. After much searching I chose to buy a Keil Kraft SkyStreak 26 control line stunter kit which gave me many first time building issues.
To cut a long story short, I started the ED Bee 1cc diesel and with an expert flying it, it performed less than one lap of the circle before it disintegrated before my eyes.
Turned out that I should have used something called shrinking dope to reinforce the balsa and tissue covering and not just the coloured variety which I had applied to match the amazing picture on the box.
My next model was the KK Champ with a solid balsa wing which taught me to fly and survived many happy hours of control line flying.
Forward to a few weeks ago and while searching through Outerzone plans site there was a copy of the original plan for the SkyStreak.
I was immediately transported back half a century and a plan sprung to life. (I just had to have a go at building some of these early control line stunters as RC foamies and see if I can get them to fly.)
Stick the plan into Adobe Reader X, print and tile it to 36" span and use the outline and former shapes, to build it in foam for electric RC.
Looking at the plan view the fuz is flat sided with a flat bottom and a curved planked turtle deck top. I figured that this would be perfect for a sheet foam sidewall, bottom and top build.
A search through the squirreled foam in the basement found some flat television packaging foam with right angled protrusions moulded onto it,
( pic1) perfect for the fuselage.
The outline was cut form the plan and used to cut left and right sides which were then placed over the fuz plan view and the protrusions trimmed until it matched the plan view profile. It was then gorilla glued together.
( pic 2)
Next the wing cores need to be cut from 2 inch thick foam board.

[mclarkson]

Best of luck with the build. Keep us updated.

[riverrat]

Subscribed.

[pd1]

Recycling of the highest order..
The airplane will be better than the packing material ever was.

[baz49exe]

Thanks very much guys. This is a real experiment and I'm going to try to do things differently to make it as simple as possible as I go.
So far the fuz is rubbish and hopefully most of the rest of the model will be too.
I've cut out the wing plan , drawn the outline onto the foam board and cut the blanks.( pics attached)
This time I'm going to use stiff cardboard for the wing hot wire profile cutting templates as they are far easier to make than those cut from hardboard which require a jigsaw to cut them out. All I need this time is a pair of scissors.

[solentlife]

Hi Mate ...... funny you being on Outerzone .... I've got a few gems of there last few days ....

KK ... I had the Radian .....

There's one plan I'm still looking for ... Veron Sopwith 1 1/2 Strutter .... 3ch RC job ..... I had one and converted to 4ch ... back in 80's.

Nigel

[baz49exe]

Hi Nigel, it's a great resource isn't it. In the early 60's I had the Phantom, Marquis and the Champ as well and the plans are all on there. It would be good to build them for RC this time around.
I'm enjoying your Lanc build. A great idea, especially as the aircraft has direct links to your mother.

Barry

[baz49exe]

Luckily the cardboard wing profile hot wire templates work well so that saved a great deal of time cutting and sanding board ones.
The two halves were joined with gorilla glue ( my new favourite modelling tool) and the full length ailerons were cut away from the wing. These are too thin to use anyway and will be added in balsa.
A full length balsa sub spar was glued to the rear of the wing to take the aileron hinges and provide a firm fixing edge.
The wing bottom was grooved to take a tapered spruce spar shaped from 12mm by 4mm strip bought at the local DIY store.
Again this was gorilla glued into place and left to dry.
The whole assembly was sanded and given a coat of spackle which was then sanded again, when dry.
Now I could test fit the fuselage to the wing.
To make things really simple I've decide to make this a one piece model. No wing fixing to worry about and the whole fuselage top as far back as the rear of the cockpit will become a removable hatch for gear access.
Just need to silk and varnish the wing now and then I can glue the fuselage and wing together.

[solentlife]

Originally Posted by baz49exe

Hi Nigel, it's a great resource isn't it. In the early 60's I had the Phantom, Marquis and the Champ as well and the plans are all on there. It would be good to build them for RC this time around.
I'm enjoying your Lanc build. A great idea, especially as the aircraft has direct links to your mother.

Barry

Certainly is ...

Lancs on a suspension at moment .... I'm very ill and waiting MRI at hospital ... plus on top I have Flu ! I went flying today - got so fed up indoors I braved it ... paid a price when I got back home though ...

I'm just fiddling with stuff .. the twin Parkjet was easy - but has proved to be unworkable with the high power motors ....

I'll keep admiring what you do !!

Cheers
Nigel

[pd1]

Here's the link for silk.
http://www.dharmatrading.com/html/eng/3374-AA.shtml

[baz49exe]

Paul, thanks for posting the link to Dharma trading. That is exactly where I bought my silk back in July 2010. I've just checked and I had 9 yards of 36"wide 5 momme shipped to the UK for $24-85 back then. great value!
I've since used it to cover three 60" plus span models, two 42" to 48" models and two 36" span models. That's a load of covering for the money and I've still got quite a bit left on the roll.

Michael, you won't be disappointed if you use it on the Harrier. I covered my GWS P-51 after having flown it in bare foam for a few years. I took the opportunity to upgrade the motor and the airframe is really far more resilient with the silk in place. It doesn't add a great deal of weight either and it makes adding a colour scheme so easy.

[baz49exe]

The Skystreak as it now is ready for the test flight. I'm not going to do any more to it until I see if it actually will fly.
In the end I decided to use the hatch fixing method which worked on the Wellesley build. The top hatch slides into the rear of the cowl and when it is slide rearwards slightly a peg locates into the hole at the rear of the cockpit.
The set up of the aileron servo is totally new for me as I've always used torque rods for a single fuselage mounted aileron servo before but this operates smoothly with little or no play..
I've kept the gap on the bottom of the fuselage at the rear of the wing as it will provide though air flow and a clear air space for the aerial.
I only hope now that it has aileron authority and I'll discover that at the first hand launch. I hope it goes better than my first did in 1960.
It really should go in fact as the AUW with a 1000 3c lipo is 13.5ozs
With 138 watts available as the low power setup that gives 163.5 watts per lb which should be plenty but if I fit the 200 watt setup that gives 237 watts per lb which is more than enough.

[riverrat]

Barry

Looking Very nice.

Good luck on the maiden.

Regards
Jimmy

[pattern14]

Looks amazing from something made from old packing. I'm sure it will fly very well. Here's hoping your weather plays the game

[Bill G]

Looks like you've got it sculpted very straight, smooth, and true.
With the nice surface you have, one of these days I'll have to talk you into trying my favorite Coverite Microlite, made in your own homeland. Obviously it doesn't look as good as your paper or fabric covering jobs, but really light. I think you'll have an insane amount of power with this one also.

[baz49exe]

Jimmy, thanks very much, hope you are all well there.
I will indeed need luck as it is after all a control line model with flat wings .

Micheal, the weather has turned bright and cold so tomorrow may well be a flying day and I can try it out. I really hope so. Whether it will actually fly or not it's been great to see the shape of my very first plane in solid form again. If it doesn't I'll just hang it in the workroom but to see it fly well would be great!!

Thanks Bill, I need to check out Microlite. Is it as strong as silk? I need the strength of the silk to support the foam as it gives the structure to the whole frame really.
I don't really like a lot of power. It's just a bonus in this case.

[Bill G]

Originally Posted by baz49exe

Jimmy, thanks very much, hope you are all well there.
I will indeed need luck as it is after all a control line model with flat wings .

Micheal, the weather has turned bright and cold so tomorrow may well be a flying day and I can try it out. I really hope so. Whether it will actually fly or not it's been great to see the shape of my very first plane in solid form again. If it doesn't I'll just hang it in the workroom but to see it fly well would be great!!

Thanks Bill, I need to check out Microlite. Is it as strong as silk? I need the strength of the silk to support the foam as it gives the structure to the whole frame really.
I don't really like a lot of power. It's just a bonus in this case.

The silk would probably be far stronger, although the Microlite provides a lot of stiffening. I imagine one benefit of silk or glass is that you don't need the CF reinforcement that would otherwise have to be used though, so I imagine there's some trade off there.
Nice and warm here today, although pouring rain for the past few days. Supposedly snow tomorrow, which would probably be better. You gotta love flying in a fresh, heavy snow, where you get great bad landing insurance.

[baz49exe]

Originally Posted by Bill G

The silk would probably be far stronger, although the Microlite provides a lot of stiffening. I imagine one benefit of silk or glass is that you don't need the CF reinforcement that would otherwise have to be used though, so I imagine there's some trade off there.
Nice and warm here today, although pouring rain for the past few days. Supposedly snow tomorrow, which would probably be better. You gotta love flying in a fresh, heavy snow, where you get great bad landing insurance.

Bill, it is that strong and makes it possible for me to use the very poor quality EPS foam which is so readily and cheaply available over here. The "cooler type" packaging foam which I have just used for the fuselage is better quality and cuts far better though. Depron is just amazing though and it's free if you buy enough frozen pizzas. LOL
I have considered CF reinforcement as it's cutting edge but I'm sticking with good old spruce at the moment as it's cheap, readily available and I can carve and shape it to pattern with a basic knife.
It's bright and sunny here this morning and 1 degree C. Last time I flew in snow was as a kid in the 60's when we put skies onto our control line models. I don't think it went very well as the snow didn't really last long enough but it would be really good to try that again with RC this time if we get any significant snowfall this year.

[baz49exe]

Fantastic morning, blue skies, still air and 1 degree celcius air temp.
Decided to maiden the Skystreak as the conditions were perfect. I was very concerned about the flat wing, short fuselage and the fact that it was designed to fly around on lines in the first place.
No need to have worried. It went straight away from the hand launch with no adjustment needed to the ailerons at all and a couple of clicks of up elevator trim to have her flying level.
I am really shocked at how well this design has transferred from control line to RC flight. It is as smooth as silk and feels like it's on rails.
I think I need to look at those early control line stunters in a new light now!!!

[BradT]

Wonderful, Barry. You have your building system and power setup so well sorted, that anything you tackle works brilliantly! I'm delighted for you that your nostalgia trip to your youth worked so well. :-) I'm jealous of your fine flying day, though, as the few dry days we've had here on Canada's west (wet) coast during the last 6 weeks have been very windy, blowing in the next storm front.
Brad.

[riverrat]

Barry

Good show.

I know it's got to feel great!

Regards
Jimmy

[baz49exe]

Originally Posted by riverrat

Barry

Good show.

I know it's got to feel great!

Regards
Jimmy

Thanks Jimmy,
It was so strange to see the model airborne again! A real trip into the past especially as I was almost at the same location where the original flew ( or didn't) over 50 years ago. I could actually see the spot, where I flew back then in 1960, from the flying strip!!

[baz49exe]

Originally Posted by BradT

Wonderful, Barry. You have your building system and power setup so well sorted, that anything you tackle works brilliantly! I'm delighted for you that your nostalgia trip to your youth worked so well. :-) I'm jealous of your fine flying day, though, as the few dry days we've had here on Canada's west (wet) coast during the last 6 weeks have been very windy, blowing in the next storm front.
Brad.

Hi Brad, I'm really glad that I decided to standardize on one motor setup and build the models around it. It's by far the cheapest option and it's really starting to pay off now. I want to build a four engined model next but I don't actually need to buy the power systems for it as I already have them available. I just need to scale the plans to the same ratio as the previous ones. Sounds easy when you say it quickly!

Brilliant day yesterday, makes a huge change from the awful weather of the last few months!!!

[Bill G]

Sounds good Barry. I thought it would be fine, with all that aileron control. I wouldn't be surprised if the relatively high sweep in the LE gives some added stability, like a delta. The only things that worry me much now are things like high aspect ratios, odd thrust lines, and slightly piggish proportions like Aerovans.

There are a number of scale CL plans on the outerzone site I'd like to build. About the only thing I'd probably do, is change a fully symmetrical airfoil. I imagine a number of them would fly fine as rc planes.

[baz49exe]

Originally Posted by Bill G

Sounds good Barry. I thought it would be fine, with all that aileron control. I wouldn't be surprised if the relatively high sweep in the LE gives some added stability, like a delta. The only things that worry me much now are things like high aspect ratios, odd thrust lines, and slightly piggish proportions like Aerovans.

There are a number of scale CL plans on the outerzone site I'd like to build. About the only thing I'd probably do, is change a fully symmetrical airfoil. I imagine a number of them would fly fine as rc planes.

Bill, I think the swept wing works well towards stability too. Amazing to think that it was designed way back in 49. I've actually had control issues with some full length aileron builds in the past so I was a little concerned in that area.
I've been looking at the C/L plans on Outerzone now as well as there are some great looking designs on there.