Author Topic: Shoestring project (Read 1610 times)

Gary Dowler · « **on:** July 24, 2020, 12:15:11 PM »

Just finished a pair of freelance Shoestrings. A few changes. Hollow block wingtips, fuselage is 1.5” longer aft of the wing, 1/2” longer ahead of wing, and wing chord is 3/4” longer as well.
One plane has a Brodak rib kit, but otherwise these were hand made.
First planes I’ve covered with mono. Both have OS 20FP’s for power, 3” reversed bell cranks, CF pushrods. Some might not appreciate the weight box being on top, but these were built purely for function, not for appearance points, and I wanted things accessible.

john e. holliday · « **Reply #1 on:** July 24, 2020, 01:42:50 PM »

Look great.

gene poremba · « **Reply #2 on:** July 24, 2020, 03:21:14 PM »

Nice looking planes Gary. The Shoestring is a good flyer. One of my favorites.....Gene

Gary Dowler · « **Reply #3 on:** July 24, 2020, 09:47:36 PM »

Quote from: Motorman on July 24, 2020, 08:37:40 PM

What leading edge do those Brodak ribs use?

Thanks,
Motorman

It’s a built up LE. 1/4” sq at the tip and a 1” wide strip of 1/16” sheet top and bottom

Phil Spillman · « **Reply #4 on:** July 25, 2020, 02:08:19 PM »

Hi Gary, I really like those FP .20's and have been using them on several fun to fly planes! please let us know how they work out on your Shoestrings!

Phil Spillman

Gary Dowler · « **Reply #5 on:** July 28, 2020, 02:16:40 AM »

After completing the two planes, I realized I can cut the weight a bit.
First was the wheels. Went with some ultra light foam wheels. This cut about 1/2 oz, but doesn’t affect CG much as they are only slightly already of it.
Then I realized the mufflers were quite heavy. I ordered two tongue mufflers for them. This took a further 1.5 oz off one (an 842 mufflers originally) and 2 oz off the one with a 2030 muffler, and these weights are well forward.
Both are just over 26oz now.
Now they are ready flight.

Gary

Dennis Moritz · « **Reply #6 on:** July 28, 2020, 03:17:02 AM »

Should respond slower and fly smoother. It’s possible to build these pretty light. Much depends on wood choice for the fuselage and wing sheeting. FP 20s run smooth. 1/16” ply would work. Light wood wherever else possible. I’ve played with the Midwest Magician in a similar way. Results were a competitive stunter. Also flew a Brodak kit Buster that came with light wood. The Buster hauled with a Tower 40. The Magician flew very well with a similar engine and a moderate venturi. Your planes are legal in profile. Some would let you fudge your way into Classic.

Sent from my iPhone using Tapatalk

Paul Walker · « **Reply #7 on:** July 29, 2020, 08:49:22 PM »

Flown them yet Gary.

Some nice flying weather currently!

Gary Dowler · « **Reply #8 on:** July 31, 2020, 02:54:33 PM »

Quote from: Paul Walker on July 29, 2020, 08:49:22 PM

Flown them yet Gary.

Some nice flying weather currently!

Not yet. With this heat, the cooler evenings have been prime home project time. Tomorrow is on my plan for setting time aside just for this. With the different wheels and mufflers, weight dropped to about 26 oz each. One possible last pre flight adjustment, when hanging from the leadouts, what , if any, yaw angle would you suggest?

Gary

Paul Walker · « **Reply #9 on:** July 31, 2020, 05:37:54 PM »

Set the leadouts about 1/2 inch behind the CG. Hanging from the leadouts doesn't tell you much.

Set there, it will hang nose out....but you know it would do that by placing the LO's aft of the CG anyway.

Gary Dowler · « **Reply #10 on:** July 31, 2020, 06:08:56 PM »

Thanks. It will be done.

Gary

Jim Hoffman · « **Reply #11 on:** August 01, 2020, 11:32:51 AM »

My experience was a difficulty getting a consistent motor run with a tongue muffler. I eventually reverted back to the stock muffler and everything motor related got better. More consistent.

Gary Dowler · « **Reply #12 on:** August 01, 2020, 12:31:05 PM »

Quote from: Jim Hoffman on August 01, 2020, 11:32:51 AM

My experience was a difficulty getting a consistent motor run with a tongue muffler. I eventually reverted back to the stock muffler and everything motor related got better. More consistent.

Interesting. This will be my first experience with tongue mufflers. Many use them, it must be workable. Will see....

Gary

Jim Hoffman · « **Reply #13 on:** August 01, 2020, 04:09:30 PM »

Gary, my tongue muffler comment was directed specifically at the OS 20 FP. They have been fine for me in dozens of other applications

Gary Dowler · « **Reply #14 on:** August 01, 2020, 11:48:12 PM »

Success!!! Got out this evening. It was a mere 90 to, which was very nice compared to yesterday’s 104.....

Evening came and off I went. I had been out earlier in the day to mow and mark the field. Since it wore an engine I had used already, Thing 2 was up first. It was superb!! Just a little faster than I’d prefer, 4.7-4.8 sec laps. Yaw was just a little more than I’d like, and a change to the leadout guide fixed this.
Second flight was great! Absolutely stable in level flight, great pitch response, etc.

Next up was Thing 1, which had an engine I’d bought off eBay. Started fine and ran just like the other one. I absolutely could not tell the slightest difference between the two airplanes in flight. I admit that since I haven’t flown since April, and that had involved a crash, I could not make myself try anything inverted or any outside loops. But wing overs and inside loops were great.
4 good flights, 4 perfect landings, and I was a very happy boy.

By the way, I got a reminder that you should never, under any circumstances, flip start any engine fitted with an APC prop!! Thankfully I keep a small first aid kit in my stuff these days.

Gary

gene poremba · « **Reply #15 on:** August 02, 2020, 04:03:45 AM »

Congrads on your maiden flights Gary. I know what you mean about those sharp APC props. Glad to hear both models flew well....Gene

John Park · « **Reply #16 on:** August 02, 2020, 05:38:01 AM »

Quote from: Gary Dowler on August 01, 2020, 11:48:12 PM

By the way, I got a reminder that you should never, under any circumstances, flip start any engine fitted with an APC prop!! Thankfully I keep a small first aid kit in my stuff these days.

Gary

Thanks for the tip! I've just got an APC 12.25 x 3.75 for my .46LA - I'll make sure always to use the sturdy 'chicken finger' I keep in my flight box!

john e. holliday · « **Reply #17 on:** August 02, 2020, 03:44:22 PM »

Glad every thing worked for you. On all my APC props I sand the trailing edge of them to a smooth feel. Also try not to slide finger along prop edge while flipping.

Gary Dowler · « **Reply #18 on:** August 02, 2020, 04:48:12 PM »

I’ll certainly be sanding mine from now on. Wasn’t even trying to start it, just flip the engine over a couple times after fueling. One flip was all that took...... lol. Can only imagine what it might have done had the battery been hooked up.....

Gary

john e. holliday · « **Reply #19 on:** August 02, 2020, 04:52:21 PM »

We all learn by experience it seems. My Dad always said, "Learn from others experience", but I keep forgetting.

Paul Walker · « **Reply #20 on:** August 02, 2020, 05:10:26 PM »

My APC story.

Time: 2000
Where: World Champs in France.
Plane: B-17 #2.
Motors: OS 15 FP's
Props: APC 9*5.....sharp as you know what.
Rules: must hand start motors.

First official for the B-17 in France. The entire competition stopped to watch. Plane was moved into starting position on circle. 2 minute start time started. Half way through the prep process my starting finger just slid down one of the props
Instant gusher. Call (or yell) was made for a band-aid ASAP as I had to start shortly. Got one just in time to stop the flow and start the motors.

And YES, it was a four flip start!

My arm had copious amounts of blood on it after the flight.

A fun time was had none the less.

dale gleason · « **Reply #21 on:** August 02, 2020, 05:33:34 PM »

A B-17 and a P-47. In France. What a display of Patriotism!
dg

Gary Dowler · « **Reply #22 on:** August 02, 2020, 05:54:11 PM »

Quote from: Paul Walker on August 02, 2020, 05:10:26 PM

My APC story.

Time: 2000
Where: World Champs in France.
Plane: B-17 #2.
Motors: OS 15 FP's
Props: APC 9*5.....sharp as you know what.
Rules: must hand start motors.

First official for the B-17 in France. The entire competition stopped to watch. Plane was moved into starting position on circle. 2 minute start time started. Half way through the prep process my starting finger just slid down one of the props
Instant gusher. Call (or yell) was made for a band-aid ASAP as I had to start shortly. Got one just in time to stop the flow and start the motors.

And YES, it was a four flip start!

My arm had copious amounts of blood on it after the flight.

A fun time was had none the less.

Wow, now THATS a prop cut story!!