I've been talking with Geoff Goodworth about "fixing" the original Carstens plan of Bill Simons' Shoestring. As Bob Hunt has noted here, the original had a Skylark wing (Foam Flite, I think). Anyway, Geoff has been working on a plan that (hopefully) reflects Bill's actual plane better than the Carstens plan. We've been trading emails and I've seen some of the CAD drawings. There are a couple of questions that have come up that only those that knew the original plane can really answer. Perhaps Bob Hunt will chime in with answers since it seems that he knows the most about this great design.

1) The Skylark wing has a somewhat narrower root chord than the wing drawn for the Carstens plan. Should the Skylark wing be aligned at the leading edge or the trailing edge on the original plan? In other words, using the Skylark wing, either the nose moment or the tail moment is going to be slightly longer since the chord on the Skylark wing is slightly narrower. Or once aligned, should the nose or tail moment be shortened to maintain the moment arms?

2) Should the flaps mirror the Carstens plan or the Skylark? The Skylark flaps are slightly narrower at the chord than the flaps published in the Carsten plan. Looking at a picture of the original plane (top view), it seems that the flap should more mirror the original Carstens plan, but this is a question.

3) Are there other areas of the Carstens plan that are not accurate? Based on my view of pictures I've seen of the original plane built by Bill Simons and looking at the Carsten plan, it seems that the fuselage is a bit narrower vertically in the Carstens plan than tha plane that Bill built. But that could just be an optical illusion.

Anyway, Geoff really loves this plane and wants to develop a plan that is the most accurate representation of the original possible. I told him that my experience with it is limited to the Flying Models plan and what I could glean from pictures. It would really help if folks that knew Bill and have seen the original plane could contribute some of their observations. The point here is to come up with the most accurate plan possible.

Thanks for any help.

Geoff has been in contact with me, also.  He designed the remake of the Goldberg Shoestring for Brodak.  (I will get those scale Shoestring plans to you, Geoff! )

Bobby is on his way to Muncie (there I guess today) so I don't know HOW soon he will be able to comment here.  He DID cut Bill's wing, though, and we all know (those that have been around since the rocks cooled) that the magazines were notorious for getting things wrong in their plans.  Just a problem of the day of a Draftsman drawing plans in one location while the plane/designer were often hundreds/thousands of miles away.  No computers and CAD back then! LOL!!

Gettin it right is a project that needs to be undertaken.  I have no real clue as to any errors in Eric's kit as it pertains to the original (is it Bill's plane?) but we all need to try and correct any of the Classic/OTS designs if we know an error does exist.  The Formula S *published* plans are a direct example of this.  Every effort was made to draw then correctly, but thorugh no fault of anyone, they had some listakes.  This HAS been corrected by Jim before he passed.

Hi Bill

The RSM Shoestring kit is Bob Whitely's Shoestring 2000.  Pat Johnston drew the plan and it is slightly larger than the Simons model.

I started looking at the Simons model about the time I started working on the plan for the Goldberg version but I stopped when I discovered some significant discrepancies in the plan and the build article.

For example, the chord lengths for the airfoil sections both tip and root shown in the plan view and the fuselage profile are quite different.  Similarly, the Flying Models article quotes a span of 57".  The inboard wing panel is the only one shown on the plan and it measures 29".  The plan also says to build the outboard wing with one less rib and 2" shorter.

As a machine design engineer in a previous life, I have difficulty reconciling rib lengths that differ by 3/16" or more between the lines drawn for a plan view and those drawn as the airfoil sections to by used for construction or wings that finish up 1" shorter in total span than the magazine article quotes.  Too many discrepancies for this little black duck.   

Cheers, Geoff

And Bill, the plan is not a priority.  It's a drawing that this Shoestring tragic wants for reference and maybe to build one day.

So many aeroplanes, so little time.   

Geoff

Bill,

When are you going to finish that top secret, needs to know, classic plane?

I thought you had a classic plane going? A somewhat unusual one.

Bill,

How did you handle the pipe with the belly scoop?