Author Topic: ShoestRingmaster Jr (Read 1113 times)

Jeremy Chinn · « **on:** November 22, 2023, 07:51:32 PM »

I wanted to build something over the Thanksgiving break and wanted to change up a Ringmaster Junior kit that I recently purchased. I have always loved Shoestrings in the past, so I decided to turn the RJ into a Shoestring. Since I was doing that, I elected to copy the parts in the kit that I was using and leave the rest unmolested to build another day.

I used the moments of the RJ and traced them onto some paper to lay out and then draw up the Shoestring fuselage and rudder. I'm powering this one with a Norvel BigMig .074, which is a little lighter than the Fox .15 this was originally designed for, so I elected to make the nose a hair longer.

Jeremy Chinn · « **Reply #1 on:** November 22, 2023, 07:57:55 PM »

For the horizontal stab, I traced out the stock stab and then laid out a new Shoestring shaped stab that worked well with roughly the same area. I did the same with the rudder. After drawing each of these templates, I like to use 3M removable glue stick (like Post-it glue in a stick) to stick the templates to the wood and then cut them out.

Also ripped full length spars and leading edge from some good quality wood to replace the half length parts that needed to be joined in the middle and used them to frame up the basic wing.

Jeremy Chinn · « **Reply #2 on:** November 22, 2023, 08:04:24 PM »

After finishing the wing, I added Shoestring style wingtips, which takes the wingspan from 30" to 36".

I finish sanded the wing and then fit the wing to the fuselage.

Only missing the control horn and covering, it weighs 11.5 ozs (including the tank and engine). She's gonna be film covered, and should finish out pretty light.

I fly off of grass, so the wheel pants are just for the pics (I'm a sucker for wheelpants).

Jeremy Chinn · « **Reply #3 on:** November 22, 2023, 08:12:11 PM »

One more pic from above to give an idea of the areas and moments.

944_Jim · « **Reply #4 on:** November 22, 2023, 09:38:22 PM »

I fell in love with my BigMig .074s. They flipstart easily once broken in. I'm anxious to hear the flight report given the switch from a Fox .15 to the Norvel.

In short, cute plane! Consider me subscribed.

Dave Hull · « **Reply #5 on:** November 23, 2023, 12:06:59 AM »

Junior Jumping Bean?

ray copeland · « **Reply #6 on:** November 23, 2023, 06:39:31 AM »

Love it!!!

gene poremba · « **Reply #7 on:** November 23, 2023, 07:30:02 AM »

Love it! I'm a Shoestring fan myself. Nice work.....Gene

john e. holliday · « **Reply #8 on:** November 23, 2023, 10:22:35 AM »

Looks good so far. I await the finished product.

Dennis Leonhardi · « **Reply #9 on:** November 23, 2023, 01:25:19 PM »

Very Nice! Great thinking outside the box ...

Dennis

Jeremy Chinn · « **Reply #10 on:** November 23, 2023, 01:56:34 PM »

Happy Thanksgiving to all!

While dinner has been cooking, I decided that a Shoestring does not seem complete without a cheek cowel. Some very light block stock worked well for that.

Air Ministry . · « **Reply #11 on:** November 23, 2023, 06:13:18 PM »

Velly Good . The cheek cowl braces the motor mount and nose too . So theyre rather usefull . With a hole thru under the crank case , Itll cool it too , if your in a hot dry area .

Jeremy Chinn · « **Reply #12 on:** November 25, 2023, 04:40:52 PM »

The Shoe is nearly covered, and has turned out about as light as I had hoped.

8.4ozs for the bare airframe and 14.4ozs with everything ready to go (minus some aesthetic trim).

944_Jim · « **Reply #13 on:** November 25, 2023, 08:01:51 PM »

Wow...now I know I build too heavy!

Wonderful looking model. Have you run the Norvel yet? If not, I recommend breaking it in first.

I look forward to flight reports. Bravo!

Jeremy Chinn · « **Reply #14 on:** November 26, 2023, 03:46:02 PM »

Thanks Jim! Yes, I’ve run the Norvel on my test stand. I’ve actually got two, and have installed the stronger of the two. The stronger engine swung an APC 7x4 @14.5k, so it should turn the recommended APC 7x3 very nicely.

I finished the little ShoestRingmaster this afternoon.

I cut the graphics on the airplane from Monokote using the decal prints on the Outerzone website. I downloaded them, then sized them correctly and printed them. After sticking them tho the Monokote with glue stick, I was able to cut them with an exacto. To mount them, I floated them in place with Windex. I’ll seal the edges in place with acetone on a Q-tip this week.

I think it needs a pilot….

Jeremy Chinn · « **Reply #15 on:** November 26, 2023, 03:55:23 PM »

She's got a 37" span and about 250 squares of wing area.

944_Jim · « **Reply #16 on:** November 26, 2023, 06:08:20 PM »

We need an emoji for a wolf-whistle...I thought I was looking at a Carl Goldberg Shoestring! I'd say the illusion is remarkable.

Luke N. · « **Reply #17 on:** November 26, 2023, 10:43:29 PM »

Wow, great job, sure would want to hear how it flys.

Luke

john e. holliday · « **Reply #18 on:** November 27, 2023, 11:36:57 AM »

Looks great.

Scott Richlen · « **Reply #19 on:** November 30, 2023, 12:20:01 PM »

Best use I have ever seen of a Ringmaster Jr. kit!

Jeremy Chinn · « **Reply #20 on:** December 02, 2023, 07:30:41 AM »

Thanks all for the comments

I've been wanting to know what the Norvel would turn an 8-3 at, and also wanted an idea of the run time, so I set it up in the back yard and fired it up.

Engine swings the prop at just over 15k 2 clicks rich, and it runs about 4 minutes on a 1oz tank.

I also just had to add a pilot

944_Jim · « **Reply #21 on:** December 02, 2023, 10:17:17 AM »

I ran 7x3 on my Mossie. 10 cc tanks gave about 1:10-1:20, so I think you are good. I do have a bench-run of mine in YouTube if you want it.

Jeremy Chinn · « **Reply #22 on:** December 03, 2023, 09:11:05 PM »

Jim, if you have a link, I’d love to see it! I re- read my post, and I should have said 7-3.

Well, this afternoon was great and terrible.

I used my stooge for the first time and it worked beautifully.

First flight I had a slightly rich run. I’m flying on 52ft spectra, and lap times were very comfortable, but line tension was not quite as good as I’d like. Still, it flew smooth. Loops, figure eights, inverted were all great. Run time was right at 4 mins as expected with a nice warning of cutoff.

I fueled it back up and tried 2 clicks leaner. This time lap times were somewhat quicker and line tension went up significantly. Again maneuvers were great. I was having too much fun. At this point, either I got cocky, my skills ran out, or a lack of line tension got me- I tried a wing over, and as I tried to pull out, she either did not react, or she stalled. I could not tell which. She went basically straight in.

It took me about 2 hours in the shop to put the wing back on and re-cover all the damage. The repairs are good from 10 feet, would be good from 5 if the red I picked out of the box had matched perfectly. I reinforced the spars and a few other areas.

Since I was cutting into it, I elected to make a couple changes-

-It was dipping a wing in loops, so I removed a quarter oz from the tip.
-The vert/rudder never seemed as big as I should have drawn it, so I drew a new one and installed it.
-I added a pushrod brace.
-While flying, it flew like it was a little nose heavy, and the spinner broke in the crash, so I’ll fly it without this next time.

I hope there is another weekend of good weather before Christmas!