Scale 20cc DHC-2 "Beaver" Kit Build from Moustache Model Works

[David Eichstedt]

That's right, it was Rene Alvarez. He ordered the 1/6 by mistake, but it worked out well for him by screwing the dummy radial to the motor box rather than gluing it to the cowl as one would normally. FTE also has a 1/8 scale dummy radial that might fit even better. With any of these resin-cast dummy engines, there will be plenty of cutting and fitting to get them to work. I used one in my Hangar 9 P-47 and it looked really, really good.

 

[AKNick]

That's right, it was Rene Alvarez. He ordered the 1/6 by mistake, but it worked out well for him by screwing the dummy radial to the motor box rather than gluing it to the cowl as one would normally. FTE also has a 1/8 scale dummy radial that might fit even better. With any of these resin-cast dummy engines, there will be plenty of cutting and fitting to get them to work. I used one in my Hangar 9 P-47 and it looked really, really good.

Park Flyer Plastics has a 6" and 8" plastic molded 9 cyl radial for $8
The 1/8 scale FTE is 5.75" @ $33 and the 1/6 scale 7.75" for $40 and resin, so durable, but maybe kinda heavy.

Based on my calculations a 7" dia would put the dummy engine about flush with the front of the plywood engine box resulting in about a 1" recess from the front of the cowl.
6" is the diameter of the inner cowling as far forward as you can go while running into the cowl lip.
A perfect dimension is about 6.5" for this model as the full scale engine is recessed in the cowl a little bit but yet wont touch the engine box if your running a gas engine.
So I think the proper sizing is 6-7". Front cowl hole is 5.125"
The full scale engine doesn't touch the cowl, but the cowling has a flange that rests on top of the baffling, along with little c-channel brackets that keep the cowl from moving forward and aft that are attached to the cast cylinder rocker housings.

I'm liking the idea of the Park Flyer Plastics 6" at this point. It will plug the hole anyways and look close to a 9cyl radial. Being this plane is 1:6.3 scale it's a little tricky to source the "Perfect" size. Based on my limited information a 1:6.3 scale 9 cyl is about 7 1/8"

 

[WMcNabb]

Found the overall engine diameter called out in a Beech Model 17 manual as 45 3/4”, or 7 1/4” at the 1:6.3 scale factor.
This is for the Pratt & Whitney R-985 AN-1 or AN-3.

 

[AKNick]

ended up ordering the 6" version from Park Flyer Plastics, along with two 5 3/4" radials for another project, and an 8" just because it was late and... Pretty cheap. whoopsie!

 

[AKNick]

Someone else caught a little issue with the provided rudder control horn not being 6-32 threads. I ordered a bunch of hardware to see what may work. 3/32” horn bracket will slip over the unthreaded portion tightly, and thread on. It does seem a little weak to me. The aileron horn set is a little thinner than the 3/32” bracket, I would say about 3/4 of the thickness. The 3/32” bracket is basically the same horn as the 6-32” but with a larger diameter hole. So the easy fix is get a 3/32” horn bracket. If you have any doubt about the threads use the aileron horn set. The provided collar and set screw may offer the extra security.

 

[TonyHallo]

Is it possible it is 3mm?

 

[AKNick]

Is it possible it is 3mm?

quite! It was supposed to be 6-32, the prototype beaver used a dubro aileron linkage assembly which is no longer offered by DuBro so in production the factory opted to source their own parts without approval it sounds like. What bothers me the most is the threads are cut VERY shallow. There is a very small chance it would slip off, but more importantly there really isn't any way to access the linkage once it's installed. One guy on the closed FB group added an access hatch, I'm thinking this is a great idea as well.

 

[AKNick]

Ordered a bunch of dummy radial fronts from Park Flier Plastics. They are about $5-$8 a piece depending on the size. I have another project that will use the 5-3/4” this one with the 6” and an 8” because I just wanted it ha ha ha.


The 6” fits all the way in the front of the inside of the cowl with a little bit of wiggle room. With the center cut for the DLE20 and the hall sensor the plastic front rear is just barley brushing up against ply motor mount. So if you are going to buy a plastic front for cheap this is the one.

Another option would be to get a radial printed on plastic sign material and glue it in the front. I was too lazy to figure this out.

With the ply mount where it is you are limited to where you can place the dummy front radial. Unless you trim that or the dummy radial.

As for scale the 6” engine is a little bit smaller, but it cannot go aft inside the cowl for the exact placement. So in turn it kinda works for appearance.
Let’s be honest too, I just didn't want a gaping hole in the cowl and a way to baffle the air a little bit for the gas engine. It’ll get painted, and look decent.

 

[TonyHallo]

Here's a photo of a Top Flite Staggerwing I did a few years ago. Painted flat black, the push rod tubes were 1/8" aluminum tube, and the spark plug wires were 18 gauge silicon insulated wire. Looked real nice.

 

[AKNick]

Here's a photo of a Top Flite Staggerwing I did a few years ago. Painted flat black, the push rod tubes were 1/8" aluminum tube, and the spark plug wires were 18 gauge silicon insulated wire. Looked real nice.

View attachment 114914

Nice, I've done one before on the H9 WACO. It came with a black dummy 7Cyl radial and pushrods. I just had to glue the aluminum push rods in with canopy glue and hand painted the cylinders silver. Thanks for the idea with the ignition wires!

The plane I am modeling it after (N4794C) has a dark blue crankcase, chrome pushrods, black ignition leads, silver cylinders, and black baffles. I'll probably paint it black, mask and paint the crankcase blue, hand paint the cylinders/push rods silver, and if I'm feeling rambunctious I'll add some black ign wires.