SHORT SOLENT MARK IV – 2014 WINTER BUILD

[wollins]

Great things shall be produced I promise! The following 38 items are what's planned:

FUSELAGE:

1 - Rub down with ultra fine steel wool (or brillo pad depending) to create a satin to flat finish so that my panel lines will "bite".
2 - Panel lines will be applied
3 - Very subtle differential "distressing" will be applied to random panels.
4 - 23 additional lower fuse windows fabricated/installed. (into fuse cutouts like the original 12 I already have)
5 - Left side TAIL window fabricated/installed. (again into fuse cutout)
6 - Rubber window framing (indented inserts/seals) installed in all 36 windows.
7 - Bow air intake will be added.
8 - Bow hatch will be created
9 - Bow U bolt anchor will be fabricated and installed
10 - Wing to fuselage fairings
11 - Elevator to fuselage fairings
12 - Navigation dome
13 - Indented door frames
14 - Indented right side tail hatch
15 - Miscellaneous scale "bits". (like cabin radio antenna post, side air intake stalks etc etc)
16 - Rusted water line
17 - Scale decals
18 - Rivets (I expect these will run into the thousands)
19 - A BIG SURPRISE ONLY REVEALED IN PERSON! (possibly at a winter workshop/pilot's meeting)

TAIL FEATHERS:

20 - Rub down with ultra fine steel wool (or brillo pad depending) to create a satin to flat finish.
21 - Panel lines will be applied
22 - Differential "distressing" will be applied to random panels.
23 - Non functional elevator trim tabs
24 - Non functional rudder trim tabs
25 - Scale Decals
26 - Rivets

WINGS:

27 - Rubbed down with ultra fine steel wool (or brillo pad depending) to create a satin to flat finish.
28 - Panel lines will be applied
29 - Differential "distressing" will be applied to random panels.
30 - Non functional cowl flaps
31 - Nacelle exhausts
32 - Top and bottom nacelle air intakes
33 - Tip float rigging
34 - Scale spinners (I've decided to redo these from sturdier material as opposed to the ones I had depicted in the pics so far)
35 - Counter rotating scale 4 blade props
36 - Scale decals
37 - Rivets

OVERALL:

38 - Clear coat entire plane clear to lock in panel lines. 

Colin

[piker]

How will you be applying panel lines?

[gordonbw]

I worship at Mr. Scale's altar. But seriously, Colin -- will you really want to risk committing aviation after doing all this detail work?

[wollins]

I worship at Mr. Scale's altar. But seriously, Colin -- will you really want to risk committing aviation after doing all this detail work?

Thanks Gordon. Now folks will understand why I desperately wanted to get the test flight out of the way BEFORE I did all the finish details to my satisfaction. I guess I have to trust in my building/flying skills when that big day comes in the spring after all the effort the above steps will require.  Incidentally it'll probably take all Winter for me to complete it but I'm confident that it'll all (the build and the subsequent flights) work out fine.

If work permits, the plan is to attend the Pilot's meetings a couple of times over the Winter to show the different stages of finish ... at the show and tell.

Colin.

[wollins]

How will you be applying panel lines?

Dunno yet ... but I'm thinking of a combination of subtle indentation (scribing) and maybe 2B pencil.  There's certainly enough top paint on the painted surfaces to not worry about scribing too deeply. Hey I might even forgo the pencil by scribing down deep enough for primer to show though! lol!   The bottom line is however I do it it'll HAVE to be very subtle.

Colin

[wollins]

BTW, this is what the final version of the Tip float looks like painted etc. Note the tapered inner struts.

Colin

[wollins]

Guys, I've been trying to find extra long prop adapters and not having much luck.  The longest I've found is the Hyperion collet ones but at 23mm they are just shy of what I need.  Are there machine shops that would do this kind of thing?

Colin

[pmackenzie]

What are you looking for?
Is it just more thread for your staggered props?
Can you show a sketch, or mockup of what you need?

Pat

[wollins]

Yeah Pat you hit the nail on the head, I need more thread for my staggered props.  The one I have depicted in the pics (pic #2 and #3) at 26.5mm long is just a little short for my hub/s. The shaft is 5mm diameter and what I need is about 30mm long at an absolute MINIMUM ... ideally about 35mm.

Either a "collet" type adapter (pic #1) or a "back mount" type adapter (pic #2 and #3) would work but I prefer the latter type cause I've found on the odd occasion that the collet type can be out of true since it cinches down on the motor shaft itself. (which can be slightly out of true itself)

On the other hand the backmount type bolts directly onto the motor itself therefore this type tends to run true more consistently.   

Colin

P.S. BTW, the longest collet type adapter I could find for a 5mm shaft is the Hyperion one (pic 1) which is their "extra long" version at 23mm long. 

[pmackenzie]

One way around this would be to use a different kind nut on the front, a sleeve nut.
Common when using prop extensions on control line stunt models. Also a lot easier to make than a prop adapter.

I know you can get them for 1/4-28:
http://brodak.com/prop-shaft-extension-1-4-28-to-1-4-28-thread-x-3-4-long.html

You would not use the actual extension, just the sleeve nut and front washer.
You do have to open up the hole in the prop hub to fit the OD of the sleeve nut.

The one in the images is one I made out of aluminum to replace some original heavy steel parts

Pat MacKenzie

[wollins]

Thanks Pat ... looks interesting. BTW, I need a favour (to anyone reading this) ... I need the measurement of the thickness of the hub of an  APC 12x6 Thin Electric Propeller.

Thanks!
Colin

[Frank v B]

Colin,

I am holding a 12x6 Electric APC and the micrometer shows the thickness as..... 9.3 mm or .372 inches.  You do the conversion.  My brain is fried* after a long day.

Hope it helps.


Frank

* yes Andy.... both brain cells!

[electroflyer]

   Hi Colin,

  I do not know how thick the hub of your prop is, but I have used Forstner bits in the past to mill out material to allow the original prop hub to work. It cuts flat which allows the washer to sit flush against the prop hub. It is recommended that a drill press be used.

   Glenn

[wollins]

thanks guys

[wollins]

Well, I've finally found a solution to my problem.  Sometimes "function" has to trump "scale".    Ok ... so lets start from the beginning.

My intention from the start with this plane was to set it up with 4 bladed counter rotating props. As we all know the P Factor Torque effect can make our models veer off course something fierce in takeoff, (and to a lesser extent taxiing) which can result at best in a not so smooth take off and at worse a botched takeoff/crash.  In my experience the effect is even more pronounced with a multi. Using counter rotation on one side eliminates that completely. (see the difference in my CL-415 here http://temac.ca/smf/index.php?topic=4354.msg35355#msg35355)

The problem is that counter rotating props are very rare in a 4 blade configuration and even rarer still when looking for a particular size.  At the size I was looking for (the 10 to 12 inch diameter range) they are virtually non existent. Believe me I've searched! 

Not one to give up easily when faced with a challenge, I decided to make my own. Since counter rotating props are much more common in the regular 2 blade configuration I was able to source four 10x6 MAS two blade counter rotating gas props. The plan was to splice (overlap) those 2, two bladed props and make them into one four bladed one.  Years ago I had come across a few examples of modellers who had done just that so after much research I figured out how to do it.     

The only issues I saw (other than maybe a possible compromise in strength) was that one prop would not be on the same plane as the other. (it'll be slightly ahead of the other. .. not flush) This is because I did a 25% cutout opposed to if I had removed 50% of the hub. (which I've seen others do) The reason I did this as opposed to a 50% cutout was to minimise the potential compromising of the structural integrity of the now four bladed prop. This is also the reason I chose GAS props as opposed to electric props since the gas ones tend to have thicker/stronger hubs. 

1st two pics show one of my props "notched" out by 25% and the 3rd pic shows how they fit together when they're both notched out by 25%. You can see how one blade protrudes in front of the other compared to a stock APC 4 blader in the 4th pic. Don't think that protrusion will be a negative in terms of aerodynamics and cosmetically you won't see it cause it'll be within the spinner. 

I then balanced each prop separately and then glued them together using JB weld. (pic #3) Did a few tests on the now "new" balanced DIY four bladed prop and it ran up perfectly every time with no sign of any compromise in structural integrity. The plan was to do dozens and dozens of additional full throttle testing/run ups over the winter to make 100% sure that there would be no compromise in structural integrity,( i.e prop exploding/blowing apart!) before committing it to the model.

Anyways ... after all of this ... because of my paranoia of that slight chance of something going wrong even after testing in terms of the props coming apart (and the fact that there would be four of them thereby quadrupling the chances of that happening) I decided against using them. 

I then decided instead I would take the much safer route and just "stack" two x 2 bladers one on top the other to make my four blader. Not nearly as pretty, but 100% safe since there would be no cutting into the hubs thereby potentially creating a compromise in prop strength. This decision then created the problem of sourcing a long enough prop adapter that would be able to accommodate the thickness of two prop hubs.  As you've seen in my earlier post my stock prop adapter's length was 26.5mm but I would need at least 5mm of that for my nut to be able to thread onto something in order to secure the props onto the shaft.

The problem was that the props I had (the gas MAS counter rotating props) had hubs that added together were pretty much the entire length of the prop adapter. Hence my search for the longer prop adapter.  Well, after going through all of that frustration, I decided to just check to see if there were any counter rotating APC electric props in the regular 2 blade configuration in the size I needed. (10 to 12" diameter) Lo and behold I found some!  Not only that but two of their hubs together measured just under 19.5mm (see pic #5) which incidentally is just over 1 mm thicker than my original DIY spliced MAS four blader. (pic #6)

So! Long story short ... problem solved cause my stock prop adapters will have enough length to accommodate these props, no problem. A special thanks to Pat for paying some attention to (and giving input/advice on) this challenge not only in this thread but the other threads in which I had posted it as well.   

Colin