Valkyrie Designs - Lockheed Electra Junior

[Martinnfb]

few riveting pictures

[Jim Barry]

Nice pics. Thanks. That’s a Model 10-E with the sizably different P&W R-1340 fitted into bigger cowling etc.  The Electra Jr is powered by the R-985. 

[Jim Barry]

Good news, bad news

 

Bad news. I'm not detailing the back of the engine. It's just too much. I did do enough to determine that the amount of fun doing that was zero.  

 

Good news. So much easier to build now and also I'll be done sooner and with much less toil. It's not the end of the world really as the back of the engine is reasonably detailed down to the magnetos and intake plenum pipes, but for all the exhaust, the mount ring and whatever gubbins they put between an engine and the firewall, well you're on your own there if you choose to open the cowling. Because the engine does not fit in the cowling without a break in the cowling I will provide, there is an option to display it without the front of the cowling, but I do not think that is real world. 

 

 

 

Edited August 14 by Jim Barry

[RCPlym]

34 minutes ago, Jim Barry said:

Good news, bad news

 

Bad news. I'm not detailing the back of the engine. It's just too much. I did do enough to determine that the amount of fun doing that was zero.  

 

Good news. So much easier to build now and also I'll be done sooner and with much less toil. It's not the end of the world really as the back of the engine is reasonably detailed down to the magnetos and intake plenum pipes, but for all the exhaust, the mount ring and whatever gubbins they put between an engine and the firewall, well you're on your own there if you chose to open the cowling. Because the engine does not fit in the cowling without a break in the cowling I will provide, there is an option to display it without the front of the cowling, but I do not think that is real world. 

 

 

 

 

Jim, it has to get to a point into any design when the designer draws a line.

Effort V result has to come into the equation that ultimately sets a hard limit.

It is your design, so it must be you that steers things in the direction you want to take it. 👍👍👍👍👍 

 

 

[mozart]

Yep, don’t sweat over it Jim. I want to see the beauty of the Lockheed’s lines; the oily back of an engine doesn’t figure in that! 

[Hubert Boillot]

What is important is what will be seen from the narrow aperture at the back of the cowling, so that means the intake manifold pipes and possibly the circular exhaust collector leading into the engine mount fairinf. All the rest, magnetos, carburetor, even ignition wires, exhaust plenum chamber, etc. is in the 'leave-it-to-the-AMS-nitpickers-to-add-if-they-want-it" area.

 

Hubert

[Jim Barry]

Hubert, My opinion on what visibility that cowl gap provides differs. I’d go with darkness. It’s just not very big and seems to just lead to more sheet metal and maybe an exhaust pipe at best..

 

 

 

 

 

 

 

 

 

[Jim Barry]

Check it out! I’m famous lol. Lead in write up by Scott Van Aken. 

 

https://modelingmadness.com/review/civil/previews/00001.htm
 

 

[Hubert Boillot]

I think you’re right on what can be seen through the slit between the cowling and the engine mount fairing. Your pictures show the darkness there. I had not seen these, I confess.
if anything, as there are no cooling baffles between the cylinders, a tubular « blob » to figure the exhaust collector and avoid a see-through effect between the cylinders to the rear opening will largely suffice …

Hubert

[Jim Barry]

Fixed the rocker arm sleeves to fit more exactly in their positions.  Also worked the fit of the engine and cowls so assembly is easy.  That was hard. 

 

 

 

[Jim Barry]

If you ever get around to putting rivets on your 3D model, just go to the mirror and take a long look at yourself and just ask "What did I do to deserve this?" "Where did I go wrong in life?"  Ha ha. Just kidding, it's not so bad, but compared to adding visible features and all, it's just really dull. It is the sanding of 3D modeling. 

 

I wish I could share my thoughts on what's next but I must keep all attention here lest we think this is that boring old Lockheed model before I'm even done.  

 

 

 

Note about the amount of data in this photo and it's only half the kit, but it will only appear in Elegoo Satellite for a few minutes before the program crashes inexplicably. This is not really a problem, I just like how it looks in that software and it will be printed in parts obviously. Fusion is still handling all just fine, but only in assembly mode when I place everything on one workspace for fit testing. 

 

 

[Jim Barry]

Took a rivet break to work on some kit production work, in particular how the landing gear will be fitted into the wings. I have a lot of confidence that the 5mm resin column will be strong sitting in a 4mm deep hole, but I wonder about the long term and think customers might too, so I cut a 3.07mm hole nearly all the way through the part and just ordered some 3mm brass tube to fit in it. Should be good. People whole like to fiddle with tiny parts making up landing gear are going to be really disappointed here. It's just one part! Adding brake lines will be a plus. I'm not modeling that. 

 

 

 

 

 

[Hubert Boillot]

Relieved you chose to enable a brass reinforcement, Jim. Resin kits tend to be heavier than IM ones, and the risk of the landing gear buckling under the load over time is real. With a 1 mm brass rod, you’d probably would have still been ok. My one-pound Potez 25 holds true with a 1mm rod in the landing gear legs, and with 1mm rods in the struts to hold the 186 grams parasol wing …

One thing I found when printing the resin leg and struts fairings was that an extra 0.2 mm in the hole diameter vs the rod diameter was barely enough to cope with the resin that stuck in the hole even after washing and subsequently cured … I was blowing compressed air through the holes after washing and before curing, and it was still not enough to remove all residual resin …

Scraping the inside of the hole with a chiseled rod to bore the struts to the right diameter was almost as painful as addIng rivets in the Electra design 😉 …

I would recommend some trials, and probably to have the hole go through the whole wheel to diminish the suction effect in the hole that keeps unwanted resin in the bore …

 

HTH

 

Hubert

[Jim Barry]

Thanks. I'll expand the hole diameter and depth as you suggest.  I'll certainly be testing so no one has to go through what you did! 

[Hubert Boillot]

Just another remark (aka the return of Jiminy Cricket 😂) regarding how you show the R-985 in its cowling.

 

When installed, the R-985 has one cylinder vertical on top,  and two cylinders at the bottom, between which fits (snugly) the oil sump. The oil sump is not figured in your R-985. It attaches to the two spigots shown on the front between two cylinders (the bottom ones 😉) and to a similar plate which is an integral part of the rear casing … This sump is a complex shape, wider at the front and narrow at the back, to fit between the two bottom cylinders. Viewed from the bottom, it has a kind of Y shape, and it took me some time to figure out its proper shape in 3D.

 

I can send you the design file for the oil sump, to speed up your design process.

 

Hubert

 

PS: the disposition with one cylinder vertical, on top, is true for all 9-cylinders and 7-cylinders radials, and the front row of all multi-row radials …

 

PS2 : i got mixed-up with my memories of the R-1820 oil sump in my description of its plan shape. The R-985 had a rectangular plan shape, but a front view of two rectangles lîked by a tapering profile. Here are the pics of my design, 

 

from the front :

 

 

 

 

 

… and the back :

 

 

 

I must have better pics somewhere, without the cylinders, but I need to find them first …

 

Edited August 18 by Hubert Boillot