Hat Band

[Jmk89]

Thanks Dave

[Jmk89]

Some further developments.

While making some researchers into Hatband on the Internet, I came across a memorial website for JOD (JOD.org.uk).

This gave me an email address to John's son, Robert and I wrote to him asking if he can give me any help in relation to Hatband.

Robert responded very promptly and indicated that there were a huge number of boxes of material that now resided at his place which he had not yet been through and catalogued. There may be some material in that.

Obviously, I am not in a position to offer to help Robert with this task since he is in the UK and I'm in OZ. However, it would be a pity if this treasure trove of free flight material were to be lost. I wonder if any of our UK HPA members might feel moved to offer assistance to Robert in going through John's collection of material. There seems to be at least one whole box of plans and it would be great if those could be scanned and put up in HPA.

Meanwhile, I will continue my hunt for information.

[Jmk89]

I have continued my searches by emailing Mike Woodhouse and Martin Dilly to see if they had any clues for finding a plan/drawing/details of Hatband.

Very kindly, they both replied within a few hours.  Neither had much info to add, although Mike corrected my understanding of a "freewheel/fold" prop mechanism that JOD mentions in his 1970 Sympo article.  It isn't a Montreal stop, but is a prop with a freewheel that also has a tension stop.  The idea is to miss the few turns at the end of the motor run when the part of the prop hook that hits the stop on the back of the nose block clunks on the stop but keeps on turning, but more slowly.  That can lead to uneven folding and a bad transition.  The idea is that the freewheel will happen on the first touch and release the power - then the prop shaft engages with the stop and the prop hub stops turning and the prop blades fold cleanly and in the same place every time.  I must try this sometime, even if I don't build a Hatband.

I also asked Martin and Mike for email addresses for some other modellers to contact who might be able to help.  I will now follow up with them (except perhaps for Dave Hipperson, because he may already have been contacted by Bill Dennis already according tho Martin's response).

PS  No reply to my email from Louis Joyner yet.

[billdennis747]

Yes I contacted Dave but he couldn't help

[Jmk89]

Yes I contacted Dave but he couldn't help

That's a pity, but many thanks for trying that. I won't ask Dave then on this subject!
 I do have one other lead - Steve Philpott was mentioned in the 1980s as a friend of JOD (courtesy of being able to text search my electronic versions of AM).  So I have emailed him (Mike Woodhouse gave me his email address).

[Jmk89]

My reply in post #17 might be misleading - that is a form of freewheel/fold device, but I don't think that it is what JOD meant.  I had a niggling doubt and thought that he may have mentioned this device in his articles from 2014+ in the relaunched AeroModeller and I was right.  In his second article (in issue 923) he described it and thr is a good drawing and diagram. 

I attach a copy of the relevant page

[Jmk89]

I took advantage of the miserable weather in Sydney today to collect all the information that I have been able to track down about Hatband and laid it all out on a big sheet of tracing paper.  One helpful source was the descriptions of JOD's Jetex models, since his first iteration of Hatband used a 32" wing from such a model.

Like a lot of John's models, it and Hatband used Union Jack construction for both the wings and the tailplane, so I was able to get an idea of the sizes of wood used from what was used in the Jetex models.

It has been a bit of an exercise like a scale modeller trying to work out how his subject was dimensioned and put together.

I am not sure that the model will be accepted as a pre-1970 design for next year's postal comp.  The rules say that you have to build it as per the plans.  Difficult when there are no plans (did JOD not publish his contest models as part of trying to get a competitive advantage?).  However, my version will be a deliberate attempt to create a faithful replica, relying on John's description of the model, the photos we have and our knowledge of John's techniques from the 60's.

In one sense, I find the rules a little silly.  You aren't allowed to change a dimension of a piece of balsa, but you can use a bought in prop and noseblock!  That seems to be directing questions of authenticity to the wrong issues IMHO.

Anyway, I think that the project will start in the next few weeks.  As well as drawing up something to help with building the model (outlines and spacing rather than a plan), I have copied the wing section from the Jim Baguley drawing of Mike Burrows' 'Wireworm Mk IV' on page 128 of the 1964-5 Zaic Yearbook and scaled it to the correct dimensions for Hatband. 

From that I was able to generate using my 3D printer wing and tailplane rib template (straight and diagonal) as well as sanding blocks for upper and lower surfaces of the wing and tail - the sanding blocks help a lot when it comes to getting Union Jack constructions nicely smoothed to a uniform profile.

[OZPAF]

Thanks for the info on JOD's modified Montreal prop arrangement. It looks like a good way to go.

Good luck with "Hatband".

John

[Jmk89]

Thanks, John. I suspect I'll need it

[lincoln]

Pardon my ignorance, but does the "hold pin" in the JOD prop arrangement hold the prop against a fully wound motor, remaining in place by friction, and springs forward to release when you turn the prop back just a tad? Also, if I understand "pre-tensioning" (first paragraph, upper right), couldn't one just stuff something in the offset loop until the motor is hooked up?

[Jmk89]

Lincoln

I think you are right on both points.

[Jmk89]

I've actually made some progress on building my replica Hatband!

But I'm leaving this post in this thread because it has to do with JOD and how, from 10,000 miles away and 1  1/2 generations younger, I have tried to understand his design process.  That is necessary because to build the model answers need to be found to a whole lot of questions that are not answered by the available material on Hatband.

The story has to do with the wing airfoil for Hatband. We know from the 1970 Sympo notes that John wrote that the airfoil was one used by Mike Burrows for one of his A/2 gliders. Apparently, John rescued the glider, which Mike had lost at a competition, and while taking care of it, he made a copy of the airfoil. We don't know how he did that. But, assuming that the wing was a two-piece wing joined at the fuselage (which is how it appears in the 1964-5 Zaic Yearbook), I imagine he stood the wing root end on on a piece of paper and traced around the edge. Obviously there might be some degree of inaccuracy in this process, which, in pre-photocopying and personal computer days, would likely have been exacerbated when that wing section was scaled down to 4 1/4" for the wing of Hatband.

When I made a 3D printing model of a wing rib using the Burrows section as shown in the Zaic Yearbook, and scaled it for a 4 1/4"chord, the shape looked remarkably familiar, particularly when I got rid of the spars that Burrows had used and put in the notch for a thin spar at about 25% cord as shown in the photographs of Hatband. The whole thing reminded me very much of the wing section that John used for his Teachers Pet P-30 design - which also has a chord of 4 1/4"! When I printed out the plan of Teachers Pet (available on outerzone.co.uk) and compared it with the 3D printed rib template, they were almost identical, except that the last 20% of the rib had been slightly thickened in the JOD form.

It is consistent with John's approach as I see it that if he had found a section that climbed and glided well for small rubber models, he would be likely to continue to use it. Indeed, aside from changing the wing structure from a Union Jack system to a straight rib system and reducing HB's span to 30" to use on TP, TP and HB have very similar wings. Accordingly, I thought that it was likely that John would have used the same leading edge, trailing edge  and spar dimensions for TP as he had used for HB.  So those dimensions are now being adopted.

Knowing from his writings that John had very definite views as to the desirability of wings having the warps that the designer wanted rather than moving around as the model saw fit, the idea of thickening the trailing edge from the 1/16" that would have been required to use the Burrows section as published, and using a 3/8" x 1/8" trailing edge on HB (like with Teachers Pet) seemed very likely.

What does that tell us about JOD? It seems to me that, as Bill Dennis put it earlier in this thread, if John did something it was because he had had thought about it and he had good reasons for doing it and he would argue strongly to support his view. Once he found something good, it was only if he was convinced that something better was available, that he would he change. It wasn't that he was obstinately conservative, but he didn't value change just for its own sake. A change was only worth making, if it really improved things. So, for example, a lot of his ideas on propellers were the result of the work that he and his brother Hugh did in the 1950s. That didn't stop him trying new things. For example, he examined closely the different variations from helical pitch that Schwartzbach and Doring  advocated at different times. Like a true engineer/scientist, he would try them himself (or look very closely at other people's experiments) and decide whether there was a real benefit. Therefore, if John said that something new was good stuff (like the Larrabee blade shape), then it truly was. Similarly, it was John, I believe, who was among the first to use Mylar film for free flight models. In those days it was called Melinex in the UK and he used a metallised version on fins and tail planes because, when compared to doped tissue, it was lighter, more waterproof and gave some benefits in terms of model visibility .

Accordingly, given the history of the wing section used for Hatband, I've decided to use that shown for Teachers Pet. And a new 3D printed set of templates has been manufactured today and hopefully tomorrow the sandwiches of straight and diagonal ribs will be shaped.

PS   In case people think that I am an unquestioning adopter of everything that John said, I will point out that unlike John, I have always found the "sandwich" process of creating ribs to be far superior for me than trying somehow to cut the ribs out separately from a sheet balsa. Even when using pins, to hold the sandwich together, I didn't ever see the structural weakness that John alleged (although I usually put in gussets to support the area at the trailing edge that might be weakened by a pinhole). Now, however, I use the process that Steve Higginson mentioned in an early issue of the relaunched Aeromodeller of gluing the balsa blanks and the rib templates together using glue stick and, once the shaping is finished, soaking the whole lot in isopropyl alcohol to dissolve the glue. Although it's a bit of a faff and slows the process down a bit, it does produce very consistent rib shapes. Further, my abiding weakness as a builder is a tendency to rush things, so getting ahead of myself in terms of the steps to be taken to build correctly.  So having to wait for a process to finish before continuing, gives me time to make sure that I have the next steps clear in my own mind .

I think my next rantings on Hatband will be in a new thread focusing on the build itself.

[calgoddard]

Jmk89 -

Thank you for this starting and maintaining this wonderful thread. I am very impressed with your diligence.

I didn't see any pictures in this thread so I decided to add one.

In the picture below, a My Coupe designed by Bill Vanderbeek is shown on the left and a Hat Band coupe desgined y John O'Donnell is shown on the right. This picture appeared in an article by Louis Joyner in the AMA's October 2023 Model Aviation magazine. Both models were apparently built by Louis Joyner. Here is a link to the article:

https://www.modelaviation.com/What-to-Build

This is a quote from Louis Joyner's article: "As far as I know, no drawings of the Hat Band are available." He apparently built his Hat Band coupe using three photos of a Hat Band model and a detailed description in an old article.

The Hat Band coupe appears to be a relatively small coupe and might be at a competitive disadvantage against a larger vintage coupe such as the My Coupe.

Bill Vanderbeek is a legendary free flight modeler in the US (Nevada).  John O'Donnell  (deceased) was a legendary free flight modeler in the UK (England). I suspect that both of these coupes would be excellent fliers.

If Jmk89 could post a copy of his plan for the Hat Band coupe on the plans gallery for HPA III it would definitely be added to my build list.

Keep up your good work Jmk89 and thank you for creating and maintaining this thread.

[calgoddard]

Jmk89 -

Oops, I see from earlier posts that you are already well familiar with the article  by Louis Joyner in Model Aviation magazine. Did you contact him to get a copy of his plan for the Hat Band coupe?  If you were successful please add it to the HPA III plans gallery. Thank you.

[Jmk89]

Jmk89 -

Oops, I see from earlier posts that you are already well familiar with the article  by Louis Joyner in Model Aviation magazine. Did you contact him to get a copy of his plan for the Hat Band coupe?  If you were successful please add it to the HPA III plans gallery. Thank you.

No Cal, Louis Joyner did not reply to my emails to him, so I didn't get any help there.

As mentioned above, so far there are just what I call construction drawings, not a plan really - just outlines and positions marked but no detail.

However, if the model comes out OK, I will make those drawings prettier and then arrange for them to be more generally available - Plans Gallery, or who knows, AeroModeller article with plans available from them?