By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by CML

Majestic Major (electric) build.

All Topics | Latest Posts

Search for:  in Thread Title in  
David Mellor18/10/2018 10:01:58
avatar
1276 forum posts
611 photos

My last build was an electric Junior 60, and I like it so much I thought I'd build its big brother - the Majestic Major.

The Junior 60 was designed by Albert E. Hatfull in the mid 1940s. The basic design remains more or less as Albert intended, though there are a small number of different plan versions of it.

The Majestic Major, on the other hand, has a much simpler design history, and there is only one plan - the Ben Buckle plan.

According to the Ben Buckle website, Ben simply upscaled the Junior 60 plan by the largest amount possible on the "machine at UDO Wessex" in the early 1980's. The linear scale factor is reported as being "1.4 and a bit" times larger than a Junior 60.

So.... I bought the plan from Ben's son Colin who runs the Ben Buckle business and will try to use up some of my balsa stock.

Meanwhile, here is a photo of my Junior 60 to be going on with.

p1010198.jpg

David Mellor18/10/2018 10:09:08
avatar
1276 forum posts
611 photos

I should correct my first post slightly by adding that, having enlarged the Junior 60 by a little over 1.4 times, Ben made some minor alterations to the wood sizes and to the spar arrangement in the wing.


Interestingly, the wood sections he came up with for the Majestic Major are for the most part somewhat smaller than would be predicted by the scale factor.

David Mellor18/10/2018 10:18:14
avatar
1276 forum posts
611 photos

To make a start I had to clear quite a big space to accommodate the plan.

I'm using an 8 foot x 3 foot plasterboard as a building board. I like this method as the plasterboard is nice and thick and takes pins extremely well.

The build will be in our garage which gets pretty cold in winter.

Taking photographs for the build log is an interesting experience because the plan is so large that I have to use stepladders and stick my head up in the rafters to get sufficient distance between the camera and the plan in order to get it all in.

Here's the "empty" plan/building board before building starts. I've smoothed the plan out under a thin sheet of plastic to keep the glue off the paper. A line of bricks at either end keeps the plan reasonably flat.

p1010252.jpg

eflightray18/10/2018 10:38:43
avatar
560 forum posts
127 photos

A great plane, I eventually sold mine to make some room for another project, (never could get used to small modells).

ray6.jpg

Ray.

David Mellor18/10/2018 10:41:01
avatar
1276 forum posts
611 photos

Hi Ray - your threads on the Majestic Major are one of the reasons I started this build!

Dave

Peter Miller18/10/2018 10:46:36
avatar
9739 forum posts
1152 photos
10 articles

I had one many years ago.It had a Merco 61 in it, also a camera.

If you look at the wood sizes you should find that the cross sectional area in sq. 1/16ths will be about the same. i.e, 1/4" sq has 16 square 1/16ths so 1.5 times enlargement would result in 3/8 sq. which would be 36 sq. 1/16ths or over twice the cross sectional area while 5/16" sq would be 25 sq. 1/16s, about 1 1/2 times the cross sectional area which would seem about right.

eflightray18/10/2018 11:12:04
avatar
560 forum posts
127 photos
Posted by David Mellor on 18/10/2018 10:41:01:

Hi Ray - your threads on the Majestic Major are one of the reasons I started this build!

Dave

 

Just checked, it was 16 years ago when I built mine, time flies faster than models now. wink

Ray.

Edited By eflightray on 18/10/2018 11:12:30

Stearman6518/10/2018 13:31:30
avatar
769 forum posts
893 photos

1964 when I first saw one of these. It was over 10 years old then. It only came out on special occasions (hot sunny Sundays) with the owner & his wife carrying it assembled from their car to the flying field. Sadly both have passed now, but still in my memories. Salute to the late John Wood of ODMAC.

David Mellor18/10/2018 15:20:12
avatar
1276 forum posts
611 photos

I've made a start on the fuselage.

The construction is very simple - make two sides initially, then add cross members.

Based on my experience making two electric Junior 60s, I now have a way of making the construction even simpler.

I make the entire nose-section up to Former 'A' (was F1 on the J60) as a separate unit which slides over the hardwood beams of the fuselage and bonds directly to them and Former 'A' (FA). The advantage being that it is much easier to construct a nose and slide it on (with motor) to test for balance and looks. That pugnacious nose is an important feature, I think.

The fuselage-sides are therefore easier to build as there are no solid balsa infill panels to glue in place until you are happy with the nose job (which is removable and replaceable until you are happy with it.

David Mellor18/10/2018 15:50:02
avatar
1276 forum posts
611 photos

Here's a couple of photos of the first side of the fuselage under construction. The first one shows the 3 main longerons, each of which consists of multiple parts.

The 3 longerons were made and dried separately prior to fixing on the building board because the joints are particularly long and easily disturbed by the struts and diagonals.

The lowest longhorn comprises 4 x 3/32" laminations, the outermost two being hard balsa and the innermost two being medium balsa.

p1010253.jpg

David Mellor18/10/2018 15:58:24
avatar
1276 forum posts
611 photos

All the "old hands" at building will have their own favoured methods, and I'm not wanting to teach anyone to suck eggs here.

My method is to use scrap balsa blocks to clamp the longerons, struts and diagonals rather than pinning directly through them.

Here is the almost completed side, showing the scrap balsa clamps in use.

p1010256.jpg

David Mellor18/10/2018 16:03:30
avatar
1276 forum posts
611 photos

I've just removed the first fuselage side from the building board.

It weighs 2.45 ounces.

And.... a couple of shots showing the exact number of scrap balsa blocks and the exact number of pins used to hold everything in place whilst the glue dried on the first fuselage side.

In the next couple of days the second fuselage side will be constructed directly over the first side, not the plan (which is now rolled up until needed again).

p1010266.jpg

p1010261.jpg

p1010262.jpg

David Mellor19/10/2018 14:43:01
avatar
1276 forum posts
611 photos

Now that the first side of the fuselage is made, it is time to start the second side.

I've pre-made the 3 important longerons so that their glued joints are not stressed when the structure is jigged up.

Here they are:-

p1010267.jpg

David Mellor19/10/2018 15:08:07
avatar
1276 forum posts
611 photos

Next, I used the first fuselage side and some half inch scrap balsa blocks as a jig, and positioned the 3 main longerons:-

p1010270.jpg

And then I glued in the struts, diagonals and triangular gussets before leaving the whole lot to cure overnight.

After that, the second side will be parted from the first-side (there is a layer of cling film between them) and allowed to dry for a further 24 hours in the airing cupboard before having a light sanding.

Here's the completed second-side jigged up over the first to ensure the two sides are identical:-

p1010271.jpg

brokenenglish19/10/2018 16:40:17
avatar
388 forum posts
28 photos

David, I'm watching this with much interest, but I shall quietly look the other way when you get to the electrical bitsmiley

David Mellor19/10/2018 17:13:44
avatar
1276 forum posts
611 photos

Hi Brian, glad you are watching.

I know you prefer the proper IC means of propulsion, so thank you for turning a blind eye when we get to the electrical bit.

Having built and flown a couple of electric Junior 60s (one in the last month or so) I have discovered the delights of what amounts to occasional radio assist to (almost) free flight. The model basically flies itself. I'm hoping the Majestic Major will do the same.

I found that your advice to keep the incidences for the Junior 60 exactly as drawn on the plan was absolutely spot on. That, I think, is the main reason my most recentJunior 60 flies so well and gives so much pleasure.

So the Majestic Major will also retain the original incidences and be flown in a radio-assist free-flight like manner.

David Mellor20/10/2018 09:43:25
avatar
1276 forum posts
611 photos
Posted by Peter Miller on 18/10/2018 10:46:36:

I had one many years ago.It had a Merco 61 in it, also a camera.

If you look at the wood sizes you should find that the cross sectional area in sq. 1/16ths will be about the same. i.e, 1/4" sq has 16 square 1/16ths so 1.5 times enlargement would result in 3/8 sq. which would be 36 sq. 1/16ths or over twice the cross sectional area while 5/16" sq would be 25 sq. 1/16s, about 1 1/2 times the cross sectional area which would seem about right.

That is exactly what I thought too.

But the Majestic Major (MM) actually uses smaller sections than we would predict on that basis.

I have the Ben Buckle plan for the Junior 60 (J60) and the fuselage is built from 1/4" x 1/4" with 3/16" x 1/4" diagonal bracing.

The J60 fuselage is 41" long compared to 58 3/8" for the MM. So the linear scale factor is exactly 1.4238 (a tad over 1.4.

A reasonable cross sectional scale factor therefore would be 1.4238 squared, which equals 2.027. Clearly a factor of 2 is about right, as you suggest. This would predict, for example, that 1/4" x 1/4" would be scaled up to 5/16" x 3/8" as the nearest section for use on the MM fuselage.

However..... the interesting thing is that the MM fuselage is constructed from 1/4" x 5/16" balsa, which is a lot smaller section than predicted from the scaling factors.

David Mellor20/10/2018 10:21:48
avatar
1276 forum posts
611 photos

Late last night I parted the two fuselage sides and placed them in the airing cupboard to finish curing the glue.

The first side weighs 2.45 ounces, the second side weighs 2.50 ounces. Built to plan sections (i.e. the 1/4" x 5/16" balsa strips).

Here they are after a light sanding:-

p1010272.jpg

David Mellor20/10/2018 10:27:26
avatar
1276 forum posts
611 photos

Those two sides are 1/4" thick - the same thickness as the finished sides on the Junior 60.

Whilst retaining the 1/4" thickness, the bottom longerons on my build are slightly oversized, being laminated from four strips of 3/32" balsa, making them 1/4" x 3/8" in section, rather than 1/4" x 5/16" shown on the plan.

In hindsight, I feel it might possibly have been better if I had also made the top longerons from 1/4" x 3/8" (preferably laminated), though as a rule I tend to frown upon the idea of "beefing up" a good design......

 

Edited By David Mellor on 20/10/2018 10:31:36

David Mellor20/10/2018 18:00:57
avatar
1276 forum posts
611 photos

It is never too late, of course.

So I have now laminated an additional 1/16" x 1/4" wide balsa strip to the top of the top longeron, bringing the overall section up from 1/4" x 5/16" (which is called for on the plan) to 1/4" x 3/8" (which is my preferred section for this structural member).

Meanwhile, I have dug out a suitable piece of plywood for the bulkheads (Former FA and FB on the Majestic Major, equivalent to F1 and F2 on the Junior 60).

Here is the "ticket" for the plywood:

p1010273.jpg

The plan is interesting, regarding FA and FB. The plan I am using (the authentic Ben Buckle plan) is designated Mark II and for some components, including FA and FB, it carries both the Mark I and the Mark II dimensions.

On my Ben Buckle Electric Junior 60 plan, F1 and F2 (equivalent to FA and FB) are called out as 1/8" ply. On the Mark I Majestic Major plan FA and FB are called out as 3/16" ply and on the Mark II plan they are called out as 1/4" ply.

Having given it a bit of thought, the Mark II section seems good to me, especially as I have to add a few holes (based on my electric Junior 60) to accommodate electrical items such as XT60 connectors.

The (exterior grade) plywood I'm using is, at 5.3 mm (measured) a little bit thinner and lighter than the usual American Midwest Products 1/4" that I would normally use:-

p1010278.jpg

Here are the rough-cut blanks for FA and FB, showing their weights before cutting holes for electrics:-

p1010277.jpg

p1010275.jpg

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!

Find RCM&E! 

Support Our Partners
Wings & Wheels 2018
Pepe Aircraft
Revoc
Motion RC
Gliders Distribution
Slec
CML
electricwingman 2017
Advertise With Us
Sarik
Latest "For Sale" Ads
Does your club have a safety officer?
Q: Does your club have a safety officer, or is the emphasis on individual members to each be their own safety officer?

 Yes we have a SO
 No, it's down to everyone

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us