Author Topic: Sky Sport Mk II (Read 2517 times)

Larry Renger · « **on:** February 01, 2009, 10:11:25 AM »

Well, I have finished and flown the second Sky Sport model. It is painted with "Painter's Choice" enamels over Nitrate dope base. I did have some cracking in the open bay areas, unfortunately. The plane flies like a dream with smooth level flight, loops and tight square corners. The added trike landing gear makes flawless landings easy! Weight came out at 9.4 ounces, and the 180 sq.in. wing provides plenty of lift to handle it. The weight also lets me use 50' lines, so lap times are comparatively relaxed.

George · « **Reply #1 on:** February 21, 2009, 09:11:23 PM »

Larry,

Nice looking plane, I like that trike gear.

I am unfamiliar with "Painter's Choice" enamels. Is this something you have used before?

George

Larry Renger · « **Reply #2 on:** February 22, 2009, 10:12:43 AM »

Painters Choice is a discount version of Rust-Oleum paint. It doesn't have the rust preventative power, but that is not an issue for our purposes. It covers well and is highly fuel resistant to Nitro, good at least to 20% level. It is nearly $1 a can cheaper than Rust-Oleum and made by them.

Balsa Butcher · « **Reply #3 on:** February 22, 2009, 10:55:32 AM »

What great looking airplane Larry. Now if you would slightly change its silohette and add round wingtips so that it would resemble an Ercoupe...

afml · « **Reply #4 on:** February 22, 2009, 01:59:37 PM »

Great looking plane Larry!

How is this one different from the first??
Tell us about your tank set-up!

"Tight lines!"

Wes

Bill Heher · « **Reply #5 on:** February 22, 2009, 06:08:37 PM »

Larry - I am curious about the tank set-up also, do the vent lines go through the fuselage to the inboard side? I don't see any in the picture.

ray copeland · « **Reply #6 on:** February 22, 2009, 06:15:31 PM »

Larry, I am a huge fan of yours, but does the kit for this 1/2a really cost $80.00 plus shipping or am i looking at something wrong? Thanks,, Ray

Larry Renger · « **Reply #7 on:** February 23, 2009, 09:29:36 AM »

To answer questions in a couple of posts above:

The tank is a bladder that is contained in the cheek cowls. No vents required. The makings for the tank are included in the kit. At first I used balloons, but now I am into re-configured plastic bags. The tank is just an air free holder for fuel, no pressure is used. There has been an extensive thread on construction and use of balloon tanks in this forum if you do a search.

The kit is pretty expensive, I admit, but it does include all hardware except the engine, lines and handle. Tank, wheels, bellcrank, horn, all included in the kit. A small model such as the SkySport has the same number of parts as a "big one" does. Laser cutting is pretty time consuming, and cutting a 1/2A kit isn't any faster than a big model. The laser machine is pretty costly, and uses a lot of power. It seems to me that Eric charges something like $40/hour to do cutting for others (you would have to check with him to get the correct number, as I am working from memory here).

The differences in the second version are that the nose is 3/4" longer to both provide better balance and more volume for the fuel tank inside the cheek cowls and the change to tricycle landing gear.

I think the resulting model is worth it if you fly competition 1/2A. Several national champions have flown the plane and approved of its performance. Tony Naccarato even says it is better than the 1/2A Pathfinder!

George · « **Reply #8 on:** February 23, 2009, 10:04:06 AM »

Quote from: Larry Renger on February 22, 2009, 10:12:43 AM

Painters Choice is a discount version of Rust-Oleum paint. It doesn't have the rust preventative power, but that is not an issue for our purposes. It covers well and is highly fuel resistant to Nitro, good at least to 20% level. It is nearly $1 a can cheaper than Rust-Oleum and made by them.

Larry,

If I remember correctly, Rustoleum uses a fish oil in their rust proof paints. Do you suppose that the "Painters Choice" excludes the fish oil, and perhaps the oil provided a "plasticizer"...which may have allowed the cracking?

BTW, although the red/yellow makes a beautiful plane, I still like the blue/cream on the first version. That was one fantastic shade of blue.

George

minnesotamodeler · « **Reply #9 on:** February 23, 2009, 05:29:24 PM »

If there's a market for $80 1/2A kits I may reconsider kitting my LittleAxe. My most expensive is $35, for a pretty simple plane. You're right, the little ones have as many parts as the big ones! Never did kit the L-A because I didn't think anyone would pay what it would cost...Thinking about it, though, it might still be more than that $80 mark. Oh well. Never mind.

Re: the paint, America's Best is another Rustoleum-produced economy paint. It also works as well as the more expensive stuff.

Larry Renger · « **Reply #10 on:** February 23, 2009, 09:52:17 PM »

I rather thought the Little Axe is a very attractive model and your wing design is very clever. Love to have the opportunity to fly one head-to-head against the Sky Sport. Too bad the distance is so far. Any chance of going to VSC? It is worth the trip from anywhere!

ray copeland · « **Reply #11 on:** February 23, 2009, 10:11:00 PM »

Larry,, would love to see the re-configured plastic baggy tanks. Would you post a picture, i have messed around with them and i can't quite get it figured out.. or if they are for sale that would be great, i am sure there are lots of 1/2a flyers out there besides me that would like to find a great running tank, maybe something even better than balloons.

minnesotamodeler · « **Reply #12 on:** February 24, 2009, 05:52:36 AM »

Quote from: Larry Renger on February 23, 2009, 09:52:17 PM

I rather thought the Little Axe is a very attractive model and your wing design is very clever. Love to have the opportunity to fly one head-to-head against the Sky Sport. Too bad the distance is so far. Any chance of going to VSC? It is worth the trip from anywhere!

Hi Larry, I appreciate the compliment, especially from one so conversant in 1/2A...I agree completely, I'd like to see how the LittleAxe performs in comparison to others. My problem in attending meets is distance, time and scheduling: Besides being in MN, far from most any gathering except Iowa's, events always center around the weekend--understandably--but, being a preacher, I'm sorta tied down here on weekends...set something up on, let's say, Monday, or Thursday, etc., and I'm there.

LIke the other Ray, I too would like to see details of your baggy tanks. I use mostly floppy balloons these days, only drawback being they do deteriorate, have to be replaced about monthly. I'm thinking your baggies are more durable than that.

Larry Renger · « **Reply #13 on:** February 24, 2009, 07:50:10 AM »

I would be happy to send a baggie to anyone who sends me a self-addressed, stamped envelope. I have about 995 of them left in the box, and the box only cost $5.

I use 2" wide, 4" long 1mil bags. Here are some photos of the box of bags, a modified bag, and the sealer I use.

Bryan Higgins · « **Reply #14 on:** February 24, 2009, 12:48:17 PM »

Larry

Nice looking Sky Sport. I sure like how it looks, great paint job....

John Rist · « **Reply #15 on:** February 24, 2009, 10:23:13 PM »

Quote from: Larry Renger on February 24, 2009, 07:50:10 AM

I would be happy to send a baggie to anyone who sends me a self-addressed, stamped envelope. I have about 995 of them left in the box, and the box only cost $5.

I use 2" wide, 4" long 1mil bags. Here are some photos of the box of bags, a modified bag, and the sealer I use.

Count me in for some. Please Email or PM me your address.

Roger Vizioli · « **Reply #16 on:** February 25, 2009, 08:56:35 AM »

Larry,
Do you have a pic/description of how you seal the end of the bag?
Thanks,
Roger V.

Larry Renger · « **Reply #17 on:** February 25, 2009, 09:20:07 AM »

As with a balloon tank, described elsewhere, I cut a piece of fuel hose long enough to go to the back of the tank and extend just beyond the end. I insert a piece of metal tubing (Aluminum or Brass, either one) about 1/2" into the end. I then cut holes in the hose in a couple of places to insure that the fuel flow can not be choked off by the plastic covering just one opening. Finally, I wrap the end of the bag over the hose and use copper wire to firmly bind it in place. You need quite a bit of tension in the wire to assure freedom from leakage. I gently pressure test the finished tank under water to insure that it has no leaks. The wire compressing the fuel hose over the metal tube guarantees the seal.

Roger Vizioli · « **Reply #18 on:** February 25, 2009, 11:29:45 AM »

Larry,
Thanks, understand!
When I saw the "sealer" I thought you had a new way to seal around the fuel feed.

Roger

John Rist · « **Reply #19 on:** February 25, 2009, 12:05:04 PM »

Quote from: Larry Renger on February 24, 2009, 07:50:10 AM

I would be happy to send a baggie to anyone who sends me a self-addressed, stamped envelope. I have about 995 of them left in the box, and the box only cost $5.

I use 2" wide, 4" long 1mil bags. Here are some photos of the box of bags, a modified bag, and the sealer I use.

I went to the Uline web site and they have 2" x 4" 2 mil bags as well as 1mil bags. Would the heaver bag be better? I can see where the thiner bag would calapes better. This is the first time I have heard of using vinyl bags as fuel tanks but it looks like the way to go. By the way, how much fuel will it hold?

Larry Renger · « **Reply #20 on:** February 25, 2009, 07:14:19 PM »

I can put about 25ccs in the tank in the compartment in the Sky Sport, probably around 30cc if the container was a bit larger. You could go with larger bags, as they are so flexible and thin that the extra will just fill whatever space is available, but not take up significant room itself. I would probably go with 3x6 bags and seal them down smaller as needed (if you have a sealer, flaunt it!). Uline also has sealers, and you don't need the big one I have, it is one I got used, cheap. Maybe e-Bay? I haven't experimented, but you could probably do the job with a woodburning tool and a lamp dimmer.

I would love to figure out how to seal in a reverse curve to make a better end to wrap around the fuel hose! The straight angle works, but the ideal would be an "S" curve. (Think of the shape of an old hot-water bottle)

John Castle · « **Reply #21 on:** February 26, 2009, 09:03:35 AM »

Interesting stuff. It occurs to me that if you have a Seal-a-Meal you could use the heat sealer built into it to seal the bags as well. Along those same lines even though it is a little heavy the bags used in the Seal-a-Meal are corrugated witch would help fuel flow when the bag is near empty..

dave siegler · « **Reply #22 on:** February 26, 2009, 01:03:57 PM »

Quote from: Larry Renger on February 25, 2009, 07:14:19 PM

I can put about 25ccs in the tank in the compartment in the Sky Sport, probably around 30cc if the container was a bit larger. You could go with larger bags, as they are so flexible and thin that the extra will just fill whatever space is available, but not take up significant room itself. I would probably go with 3x6 bags and seal them down smaller as needed (if you have a sealer, flaunt it!). Uline also has sealers, and you don't need the big one I have, it is one I got used, cheap. Maybe e-Bay? I haven't experimented, but you could probably do the job with a woodburning tool and a lamp dimmer.

I would love to figure out how to seal in a reverse curve to make a better end to wrap around the fuel hose! The straight angle works, but the ideal would be an "S" curve. (Think of the shape of an old hot-water bottle)

http://www.instructables.com/id/How-to-Make-a-Heat-Sealer/

You can make a heat sealer with stuff many of us have in our shop already. I would guess that you could make the seal in any pattern you want.

John Rist · « **Reply #23 on:** February 26, 2009, 03:36:40 PM »

Quote from: Larry Renger on February 24, 2009, 07:50:10 AM

I would be happy to send a baggie to anyone who sends me a self-addressed, stamped envelope. I have about 995 of them left in the box, and the box only cost $5.

I use 2" wide, 4" long 1mil bags. Here are some photos of the box of bags, a modified bag, and the sealer I use.

Larry is going to send me some of his modified bags (money is in the mail). When they arrive I will take pictures and post them as I build my vinal baggy tank.