I am planing way ahead of my self for building a GP shoestring.
I was planing on using a 4 stroke but I am leaning back to a 2 stroke?
I don't want to butcher the cowling up to much, but I want this plane to go to the extreme in performance.
Cost is not a issue, but speed and reliability is.

I had a TT .91 4stroke in mine and loved it. The best smaller plane I have ever owned!!!

Re: " Cost is not a issue, but speed and reliability is." < I have read that the Shoestring is a very fast plane even with a standard 60 engine such as an OS 60 so I wouldn't be trying to overpower it. If it was me I don't want to get into 90 size engines but I like the exrtra punch of the 75 engines. They don't over heat like a lot of the 90 engines if they are mounted in cowl and they are easier on fuel. The best engine I have found in that size is the Tower Hobbies 75. There is a pitts muffler available for the engine as well if the plane needs it.[8D]

How is the performance for "normal" aerobatics? I want to do the full range of stuff a normal plane would do; I have a different plane for 3-D. [&:]

There are few really quick setups for the Shoestring.

1) you can use the Jett 90LX engine, as typically installed in the Toni and Minnow. The installation is pretty much the same. Serious power. Utilize 11x9 and 12x6, 12x7 props. Photos below. The 90LX turns 11x8 over 14,500 and generally gets the 11x9 up over 14,000 too - unloads great in the air. I can provide additional details if you desire.

2) A standard Jett 90L equipped with a Turbo-Jett muffler is another great choice. Photo of install in a Shoestring below. More torque, bit lower rpm (12K - 13K range), a bit quieter. Set this up with 12x8 and 12x9 props for speed, or a 13x6 for quick and balanced performance. A little bit of cowl work involved, but nothing that does not look good when done.

I hope these suggestions are helpful
Bob

edit added: yes, the shoestring is a bit larger. Needs a 12 or 13" prop. The turbo-jett muffler on a Jett 90 works well here. If you want more prop, the Jett 100L or 120L engines are the same "60" size as the 90L, and with a similar turbo-jett muffler are very happy turning 13x10 or 14x10 props at lower rpm (10-12K range).

Well , 2 or 4, your still going to have to cut a vent in the bottome to keep fro overheating but take a good look at the side of my cowl. I run a ST G90 sideways and I cut the cowl as such not to draw much attention with a big hole in the side of it.

I have a Magnum 91 FS in mine for the sound; and it's still pretty darn fast with a 13x9 APC. For more speed and performance I would go with either the Jett .90, or an OS .90FSR if you can find one...

I have a Saito 100 in mine and it's one of the easier flying, more relaxing planes I have. Very well mannered no bad habits at all and very light. I started out with a OS 60 ABC but feel the 4stroke is a much better match. I also have a Lttle Toni with a Jett 90 and its twice as fast and a much cleaner airframe. IMO the Shoestring has too much drag in that large banana fus and too fat a wing to benefit from a powerhouse like the Jett 90, others may disagree but the Saito 100 is perfect for the Shoestring in my book. I like the Shoestring so much I may 2x the size and have a kit cut.
KirkRC

Bob Holman has plans available for a 96" ws shoestring. I was thinking about a bigger one but this is a little much for me. I would like to do something in the 80" range. Its a great flying plane. I use a OS 91 fs and its fast enough for me.

Carl

I checked that out a coupl eyears ago. I believe it was PCK who sold the kit for the use of Bob Holman plans which you had to get separately. Then you had to find or make a canopy and cowl and half a dozen other things and I blew it all off.