Miles M38 Messenger from Aeromodeller plans

[pmullen503]

Looks good.

What are the plastic looking parts of the hinge that will attach to the flaps?
Got a source for a 3.17mm collet adapter (or one with grubs screws) with a long shaft? Any tricks for drilling and tapping the end accurately?

[Bill G]

Originally Posted by pmullen503

Looks good.

What are the plastic looking parts of the hinge that will attach to the flaps?
Got a source for a 3.17mm collet adapter (or one with grubs screws) with a long shaft? Any tricks for drilling and tapping the end accurately?

The plastic parts on the flap hinges are trimmed arms from Hobbyzone control horns. Seems to be a decent grade of plastic to fabricate the parts from. The screws have a short unthreaded shank that provides the bushed surface in the ply arms, and are threaded into the grey plastic arms. I got the grey arms with purchases of the tiny Hobbyzone thumbwheel micro EZ links. They're incredibly well machined thumbwheel links, for under a buck a pair. I may use them on the flaps for this model. The small screws were also a good find at a swap meet recently, as the really small sizes are difficult to find.

The prop adapter is a long threaded nut style collet adapter from HURC. I believe they have set screw type also. The holes sure are difficult to drill on center, as they have a small nipple protruding at the very center of the bolt end that tries to knock your center punch off center. You can file it down, but the very center of the aluminum bolt seems to be the hardest part of the bolt, so it's still really difficult to punch on dead center, and even when done the drill bit likes to "walk" when drilling. Five thousandths or better within center is par for the course on a good day. This spinner cap has a small indexing rib on the base that centers it on the hub. The darn thing is a high precision part, and I'm convinced that if I was another 0.001" off center, it would not want to seat properly. One trick I use is to drill a short pilot hole, and then use a slightly smaller bit that you can intentionally force to one side of the pilot hole if needed, to get it drilling on center. The other crude trick that we all have probably done is to angle the drill bit and gradually straighten it to align it with the bolt axis while drilling.

I probably should cut a set of telescoping tubing sizes and use them as a drill bushing guide, given how many times I've done this. A piece of tubing would be fit over the bolt and filled with telescoping sizes that would downsize the hole to provide a reasonably tight tolerance drill bushing that would be on center.

[pmullen503]

The custom drill bushing sounds like a good idea.

Folding prop spinners have the correct shaft type with a threaded hole to secure the spinner. You can take the "H" piece off and mount a regular prop but you have those square holes in the spinner that have to be ground to fit the prop. I tried to vacuform a new spinner to fit the aluminum folding prop backplate for my He-219. There again it's a pretty high precision fit needed. The first try was a little too small. Worth another try though as I could cut the spinners to match the counter rotating props I plan to use.

[Bill G]

That looks about exactly like what I have now Pat for the spinner assembly. Some of these spinners get expensive. The one I bought was $10, with an additional prop adapter at around $4. It looked identical to the Maxx spinners that they had, which were around $15 for the same size spinner.

Finished the striped "jail tail". Somehow I talked myself out of masking and painting the strips on, and trimmed white iron-on covering strips instead. Worth the added effort. For some reason I mistakenly added a white stripe at the bottom of the outer rudders, versus spacing the stripes slightly further apart to avoid the need for the bottom white cap stripe. I doubt it will be readily noticed, especially considering that the plane that this is being modeled after has been painted differently 3 or 4 times over the years.

[pmullen503]

The tail looks outstanding!

Those folding prop spinners are a little spendy, especially when you don't actually use the spinner, just the collet and back plate.

Dubro electric spinners are under $5 but they come with a 3mm collet. So if you need 3.17 or 4mm, you have to buy an additional collet.

[Bill G]

Originally Posted by pmullen503

The tail looks outstanding!

Those folding prop spinners are a little spendy, especially when you don't actually use the spinner, just the collet and back plate.

Dubro electric spinners are under $5 but they come with a 3mm collet. So if you need 3.17 or 4mm, you have to buy an additional collet.

Thanks Pat. One nice thing with this spinner is that it came with 3 collet sizes. They'll get used someday, as I always seem to have a need for them sooner or later. I have plenty of collars and threaded caps, so the extra threaded shaft adapters are useful. The form of this spinner is perfectly scale correct which made it a nice find, other than being a bit oversize for perfect scale.

Not much done, as covering is only so exciting. The fuse has been covered for a while, and I trimmed white Ekonkote covering for the front striping, versus taking the easy painting route. For the rear fuse, the white top will probably be painted on, which also extends onto the canopy framing. Small cowl vents are in place now, not shown here.

[Bill G]

Close to complete and still needing a last bit of covering motivation to finish the upper wing surfaces. A bit of time was spent on the interior, with a Head & Shoulders Brothers pilot that is currently drying, after priming the added on balsa torso. You just can't stick a head on the top of a seat back, without adding a torso.

[pmullen503]

Nice!

[Bill G]

Thanks Pat.
I may finally finish this build, after finishing the wing covering. I thought about making functional doors, but I think I'll pass on that idea, given the amount of work that would be involved. The pilot has been firmly glued to the seat, since I won't be able to get in there afterward, if he were to break loose. The seats will have to be glued well to the floor also, for the same concern.

[pmullen503]

Stuff rattling around in a sealed cockpit is a bummer. I once had a P-61 (big prominent cockpit) that a tiny spider took up residence in and filled it with webs.

Really nice monokote work, BTW. Someday, I'll have to spend the time to get good at that.

[Bill G]

Originally Posted by pmullen503

Stuff rattling around in a sealed cockpit is a bummer. I once had a P-61 (big prominent cockpit) that a tiny spider took up residence in and filled it with webs.

Really nice monokote work, BTW. Someday, I'll have to spend the time to get good at that.

Haven't had that one yet but I've made some really creative wiping wires with paper towel tips for inner window cleaning. I use Pacer canopy glue as much as possible, but sometimes you need a wick of CA, which causes a white flashing over time. Fortunately it can be cleaned off, if you can get in there. It is good to try different finishing techniques over time. Someday I'll like to try your methods and a few others, since I'm completely burned out from iron-on covering. Your liquid sheeting finishes look really good.

Finally getting the final push to finish this project. Model building was a lot easier when I used to omit details such as wing fillets, although they look much better with them. Stretching iron-on covering across them without bubbles or wrinkles is yet another job that is easy to put off. The fillets can be easily made from filler, but the filler melts under the iron heat, and the covering adhesive pulls away the surface of the filler, leaving a "flapping in the wind" covering job. These wing fillets were sculpted from balsa, including the rear portion that flares into the fuse, all in one piece. Tedious job, but worth the effort and creates symmetrical wing fillets.

[pmullen503]

Looks great. It's quite a handsome plane and I like the color scheme.

Fillets, especially large ones, are always a pain.

The Styrospray/Liquid Sheeting is somewhat fussy to work with. It's sensitive to temperature and humidity and you have to figure out how to hold the coated parts while they cure. But it has many advantages. Complex shapes are easy to do. I really like it for tail surfaces and things like ailerons and flaps. Those parts are a pain to cover with lightweight glass cloth. SS doesn't shrink as it cures so you can make lightweight foam control surfaces that don't warp. Maintaining tolerances for control surfaces is easier too.

That said, nothing beats a film covered, open framed balsa structure for weight.

[Bill G]

Thanks Pat. I love the color scheme also, although I may pick a monotone scheme for the next build. For a clean look, I used the red Parklite and Ekonkote white for the canopy top, which can be applied without melting the clear plastic by setting the iron temp just high enough to iron it down. The benefit is having very clean window frame lines that also do not chip over time as paint does. These multi-color schemes are always work, although the added effort is always worth it in the end.

I'm really optimistic about this plane as it has good flying proportions, as well as finishing as light as I could have hoped for at 20.25oz AUW. Approximately 10gms of lead was added to the cowl cap, done by hogging out a bit of balsa from the rear surface and filling with lead. The CG is at 25% MAC when factoring in the flap area (27% not accounting for flap area) which should be safe considering the tail moment and large stab area. The plane is fitted for a 3s-1320 TP-PL, which should provide reasonable flight time while not being terribly heavy. I prefer to add 10gms of ballast in the cowl cap, versus having to use a roughly 20gm heavier battery to achieve the same effect, when the 3s-1320 is ample. The battery obviously is not as efficient at contributing to ballast as using ballast in the cowl cap, due to the battery location being closer to the CG.

Specs:
Span: 41"
AUW (w/TP-PL 3s-1320): 20.25oz
Wing area (including spit flap area): 1.8 sq-ft
Wing load: 11.25 oz/sq-ft

[pmullen503]

Really looks fantastic! The landing gear were worth every minute spent on them.

[baz49exe]

Looks amazing Bill! Superb work; really looking forward to the maiden report.

Barry