P-38 Lightening Epic

[Inq]

This project will be epic in length and can die on the vine at any time. I can get side-tracked by life or simply by crashing too many trainers along the way. I think this forum will be supportive, if not encouraging, but we don't know each other from Adam's house cat.

It's been a long time since I flew glow RC planes. And even then... I would have certainly not even started this project. Building with stick and frame would never have gotten me the scale realism I want nor would I have had the brains, skill or balls to sacrifice a model that took thousands of dollars and hundreds of hours to build by having it leave the ground. Now... fast forward thirty years, and I see things differently. Electric is cheap, electronics are cheap and mainly... 3D Printing is cheap, and gives me the detail I want. AND... all the time and effort goes into the CAD work. If I auger-in, I simply press the Enter key on the computer and out spits another P-38! HOW COOL IS THAT? I wish I had one of these things when I was growing up or even in my career years.

Although the P-38 isn't my favorite war plane (top 5, maybe)... there is something about model multi-engine war planes on the RC flight line. The difference between and Ugly-Stik and a P-51 (not in my top-5) is only skin deep. But you taxi out a multi-engine and everyone pauses to watch. I purchased and printed the 3DLabPrint P-38, but it wasn't to scale and lot of the dimensions are off. It's been printed, but hasn't flown yet either, because I simply am not good enough yet. It'll be the guinea-pig, sacrificial-lamb before I take this one up. Although many would find it fine, every time I look at it, my eye is always drawn to the differences. My engineering-eye also doesn't trust the lack of any reinforced wing-spars. It simply uses the plastic and in the weakest direction. I can't believe it'd take any serious G's. Besides it doesn't have landing gear... I want full retracts and doors and Fowler flaps... all the cool things that builders like to tinker with.

I haven't decided on a size yet, but it will be bigger than the 55" of the 3DLabPrint version. I've asked for some help on larger electric motors in another thread to help me come to a size... maybe something in the 72" range. I have plenty of time before I have to nail down that size... CAD easily scales. Time to get started.

Off to the drawing board...

 

[Inq]

UPDATE
Finished the basic forms for the fuselage and boom. Next... Intakes.

 

[Inq]

If I were to go 1/8 scale (78" Wingspan) is there some guidelines for how big the motors have be and how much batteries I'd need for say... 10 minute flight?

I'm looking at all these motors and it seems like lower KV swings bigger props... but I'm real confused. At the bottom end it looks like the same sized "can" (1" diameter, 1" long, brushless) can swing anything between a 6" and 10" prop. Can someone suggest some resources so I can learn how to size the motors, props and batteries?

Thanks

 

[Tench745]

If I were to go 1/8 scale (78" Wingspan) is there some guidelines for how big the motors have be and how much batteries I'd need for say... 10 minute flight?

I'm looking at all these motors and it seems like lower KV swings bigger props... but I'm real confused. At the bottom end it looks like the same sized "can" (1" diameter, 1" long, brushless) can swing anything between a 6" and 10" prop. Can someone suggest some resources so I can learn how to size the motors, props and batteries?

Thanks

I know you said you have limited internet access, so my usual go-to response of plugging your numbers in at ecalc.ch may not be the best fit.
I did a quick search for introductory articles to electric power and came across this one from the AMA. https://www.theparkpilot.org/brushless-motor-basics
It may not be exactly what you need (hopefully others will have some better tailored links) but it is a fair introduction to the world of electric flight.
I also found this one from Model Airplane News and it seems like a fairly concise overview of the electric basics. https://www.modelairplanenews.com/electric-back-to-basics/

 

[Inq]

I know you said you have limited internet access, so my usual go-to response of plugging your numbers in at ecalc.ch may not be the best fit.
I did a quick search for introductory articles to electric power and came across this one from the AMA. https://www.theparkpilot.org/brushless-motor-basics
It may not be exactly what you need (hopefully others will have some better tailored links) but it is a fair introduction to the world of electric flight.
I also found this one from Model Airplane News and it seems like a fairly concise overview of the electric basics. https://www.modelairplanenews.com/electric-back-to-basics/

Thank you for your help. Getting out to the library today and will be able to check your links in detail and hopefully surf (research) this topic in more detail. It was easy with Glow - Cubic Inches!

 

[FoamyDM]

If I were to go 1/8 scale (78" Wingspan) is there some guidelines for how big the motors have be and how much batteries I'd need for say... 10 minute flight?

I'm looking at all these motors and it seems like lower KV swings bigger props... but I'm real confused. At the bottom end it looks like the same sized "can" (1" diameter, 1" long, brushless) can swing anything between a 6" and 10" prop. Can someone suggest some resources so I can learn how to size the motors, props and batteries?

Thanks

The Aviation RC Noobs just did an episode on how to size a motor system
https://anchor.fm/avaitionrcnoob/embed/episodes/Ep-60---Sizing-Your-Power-System-e1ovarh

https://www.rc-airplane-world.com/watts-per-pound.html

• Less than 50W/lb - very lightweight / low wing loading slow flyer.
• 50 to 80 W/lb - light powered gliders, basic park flyers and trainers, classic biplanes and vintage ('Old Timer') type planes.
• 80 to 120 W/lb - general sport flying and basic/intermediate aerobatics. Many scale (eg warbirds) planes suit this power band.
• 120 to 180W/lb - more serious aerobatics, pattern flying, 3D and scale EDF jets.
• 180 to 200+W/lb - faster jets and anything that requires cloud-punching power!

 

[Inq]

The Aviation RC Noobs just did an episode on how to size a motor system
https://anchor.fm/avaitionrcnoob/embed/episodes/Ep-60---Sizing-Your-Power-System-e1ovarh

https://www.rc-airplane-world.com/watts-per-pound.html

• Less than 50W/lb - very lightweight / low wing loading slow flyer.
• 50 to 80 W/lb - light powered gliders, basic park flyers and trainers, classic biplanes and vintage ('Old Timer') type planes.
• 80 to 120 W/lb - general sport flying and basic/intermediate aerobatics. Many scale (eg warbirds) planes suit this power band.
• 120 to 180W/lb - more serious aerobatics, pattern flying, 3D and scale EDF jets.
• 180 to 200+W/lb - faster jets and anything that requires cloud-punching power!

Thank you! I look forward to watching it this afternoon when I get some Internet bandwidth. My first cheap motor didn't give a spec for wattage, but I was able to load a few Amazon pages a saw that they show these wattage numbers.

 

[Inq]

I know you said you have limited internet access, so my usual go-to response of plugging your numbers in at ecalc.ch may not be the best fit.
I did a quick search for introductory articles to electric power and came across this one from the AMA. https://www.theparkpilot.org/brushless-motor-basics
It may not be exactly what you need (hopefully others will have some better tailored links) but it is a fair introduction to the world of electric flight.
I also found this one from Model Airplane News and it seems like a fairly concise overview of the electric basics. https://www.modelairplanenews.com/electric-back-to-basics/

Read through both of these and they were perfect for my needs. Maybe someday I'll need to get deeper into it, but for quite a few models, this was perfect. Need to really get the feel for the numbers in relation to the way planes responds to get any deeper. Experience counts!

 

[quorneng]

Inq
To answer your query about the range of possible prop sizes for a typical 1" x 1" motor is it depends on how the copper wire is wound inside it!
The space available for the copper wire inside a motor is limited so you can either use a small diameter wire with a lot of turns or a thicker wire with fewer turns. The magnetic forces generated (the motor torque) depends on the amps flowing and the number of turns. Fine wire can carry less amps than thick so the diameter of wire used largely determines the motor's characteristics.
It is thus possible to create two identical looking motors with a similar maximum power (Watts) one a high speed version with a lower torque or low speed one with higher torque and any combination between. To make best use of the individual motor's characteristics will need a suitable size prop.
It can get even more more complex than that but it does show the complexities involved in designing a plane from scratch.
As has been highlighted after establishing the size of plane you intend will be trying to establish it likely all up weight as this will determine the sort of power in Watts you will need. Without quite some experience in the appropriate construction method & materials even guessing a likely weight is not easy. Actually building it and keeping somewhere close to that guess is even harder.
There are advantages in following a design of a plane that has actually been built and flown will remove many of the unknowns.
Just a thought.
.

 

[FOGeologist]

I suspect that this will have to be an "iterative process," making that I think that by the time you've made your twelfth one, you will have it all so well hammered down that you will be an ace at making it efficiently. You will know how to make it easy to print, strong enough to be light enough to fly, and what kind of power system will give it the kind of excess thrust to make it a super-efficient flyer.

Please document your process. We will all learn from your failures and successes along the way.

 

[Inq]

I suspect that this will have to be an "iterative process," making that I think that by the time you've made your twelfth one, you will have it all so well hammered down that you will be an ace at making it efficiently. You will know how to make it easy to print, strong enough to be light enough to fly, and what kind of power system will give it the kind of excess thrust to make it a super-efficient flyer.

Please document your process. We will all learn from your failures and successes along the way.

Thank you for the kind words... this P-38 is something I want to do, but it's getting back burnered.

1. As you have noted... I'm just now learning to fly in the "Cub Training (J-3)" thread.
2. Before I tackle this P-38 again, I'll need to build the "New" trainer and thoroughly get flying and test piloting under my belt.
3. Then I'll try to graduate to the Inq'd F-22 project thread. They (although I think "they" are punk'n me) say the F-22 is rather docile if made light enough.
4. After that, I hope to graduate to some of the 3DLabPrint models I already have.
   1. I'll start off with the easiest to fly - Focke Wulf Ta 152 H. It's mostly built and it's a sweet model and they've really refined their model design. It fits together very well and feel stronger than the older versions. The huge wings should make it relatively slow in the landing pattern.
   2. P-38 - They don't say which model, but it's an early P-38 with the small inlets. It is also mostly built, but it is also their early design and it's not very scale accurate. I'm designing a P-38L with the BIG inlets. I'm not too concerned what happens to this one, so I'll probably push it hard and use the "cork in a bottle" technique for someone to send it back to me... probably... after it augers-in to China.
   3. After crashing those, I plan to do their Focke Wulf Ta 152 C model with the clipped wings. I also want to import their wings, tear them apart and add retracts. I'll start looking into a bigger motor for it also. I want it to be a speed demon.
5. Then, if I haven't torn up their landing field too much, I'll work on this P-38 again with what I've learned form the above designing/building/flying models. Retract, Fowler flaps, the works.
6. Then I'm arguing with myself doing some ducted fan stuff.
   1. U2 - So I can practice sail plane flying.
   2. Horton 229 - So I can design a flying wing.
   3. Then the culmination - A F-14 Tomcat with all the bells and whistles working.

This is the ten-year plan!

 

[mastermalpass]

I plan to do their Focke Wulf Ta 152 C model with the clipped wings.

A Ta 152 with clipped wings? How's that different from a 190D? *looks up ta 152C on google* Oh... It's in between the 152 and 190D. I guess the Germans had a need to build a specific middle-ground model. Lol

I'm excited to see all that you have planned. It just never gets old seeing people who were saddled with the unforgiving balsa models come back to find how much more forgiving the hobby has grown to be. Especially when it's immediately followed by a massive build list! Half of all we dreamt about doing in this hobby has turned from fantasy to aspiration. Hell, I'd only been in the hobby five years when the Eachine Mini warbirds came along and had me astounded. Also, FliteTest have brought us some great techniques in my time - half of us are building Master Series style planes now; it just keeps getting better!

Once again, looking forward to it - especially that Ta 152C, I don't think I've seen anyone do even a FW190 in my time on here. So a Ta 152 will be cool!

 

[Inq]

A Ta 152 with clipped wings? How's that different from a 190D? *looks up ta 152C on google* Oh... It's in between the 152 and 190D. I guess the Germans had a need to build a specific middle-ground model. Lol

I'm excited to see all that you have planned. It just never gets old seeing people who were saddled with the unforgiving balsa models come back to find how much more forgiving the hobby has grown to be. Especially when it's immediately followed by a massive build list! Half of all we dreamt about doing in this hobby has turned from fantasy to aspiration. Hell, I'd only been in the hobby five years when the Eachine Mini warbirds came along and had me astounded. Also, FliteTest have brought us some great techniques in my time - half of us are building Master Series style planes now; it just keeps getting better!

Once again, looking forward to it - especially that Ta 152C, I don't think I've seen anyone do even a FW190 in my time on here. So a Ta 152 will be cool!

From what I've read... the Ta series is Kurt Tank's (Focke-Wulf's, Kelly Joshnson) last hurah! And Hitler and Göring honored him by letting him name them. I don't have all my FW books handy, but I recall the 190D and Ta 152C used different manufacturers engines. One has the big intake on the port side and one has it on the starboard side. Don't recall which manufacturer was which, but it was either Juno or Mercedes. BMW obviously did all the air-cooled radials for the FW 190 A's.

I don't get a kick-back, but the Ta152H is a really nice model. It went together very well. I'm just afraid to auger-in the first flight. The 3D models are available at: https://3dlabprint.com/shop/focke-wulf-ta152h/
The C-Wing used to be an extra charge, but now they give it away if you have the Ta 152H. https://3dlabprint.com/shop/focke_wulf_ta152_c/

If you can fly fast war planes, these are dirt cheap to print and they look like a Revel model with panel seems and everything.

VBR,
Inq

 

[Inq]

It just never gets old seeing people who were saddled with the unforgiving balsa models come back to find how much more forgiving the hobby has grown to be. Especially when it's immediately followed by a massive build list!

Forgot to add...

BUT you are definitely right. I got out of it because I could build a 1000 hour war plane, but I'd crash it in 30 seconds. Somewhat discouraging. Now I can print one... or spend all the hours CAD'ing one of my own and... Print, Crash, Print, Crash, Print, Crash... to my heart's content. Hell, it costs me more to drive to the air-field than to print a war plane.

I look forward to the day when I can use the same plane twice.

VBR,
Inq

 

[Inq]

A Ta 152 with clipped wings? How's that different from a 190D? *looks up ta 152C on google* Oh... It's in between the 152 and 190D. I guess the Germans had a need to build a specific middle-ground model. Lol

Found my reference for those interested in this Focke-Wulf minutia.
Although they look the same, it appears they were significantly different airplanes being produced simultaneously.

Excerpts

THE Fw 190 BECOMES THE Ta 152
In 1944, the Reichluftfahrtministerium decided to institute a policy of naming the designer in all new aircraft designations. In the event only two designers, Dipl. Ing. Kalkert of the Gothaer Waggonfabrik A.G., and Dipl. Ing. Kurt Tank of the Focke Wulf Flugzeugbau G.m.b.H., received this honour. Thus, further variants of the Fw 190 series were to be designated Ta 152 and Ta 153. The latter was a much advanced high altitude project with a high aspect ratio wing, a DB 603 engine and four-bladed airscrew.

The second major production version (the Ta 152 H being the first) was the Ta 152 C. This aircraft differed mainly from the earlier models in having a 1,800-h.p. Daimler Benz DB 603 E engine mounted in a longer fuselage giving the aircraft a maximum speed of 448 m.p.h. with the aid of GM-I.

SPECIFICATIONS

FOCKE WULF 190 D-9
Dimensions: Span 34 ft. 51 in. Length 33 ft. 5 in.
Powerplant: One Junkers Jumo 213 A-I twelve-cylinder, inverted Vee, liquid-cooled in-line engine rated at 1,776 h.p. for take-off and 1,200 hop. for continuous running. This could be increased to 2,240 hop. with the addition of MW-50 water-methanol injection.
Weights: Empty 7,694 lb. Loaded 9,480 lb.
Performance: Maximum speed (with M\N-50) 357 m.p.h.
at sea level, 397 m.p.h. at 10,820 ft., 426 m.p.h. at 21 ,653 ft.
and 397 m.p.h. at 32,810 ft.

FOCKE WULF Ta 152 C-3
Dimensions: Span 36 ft. 1 in. Length 35 ft. 5 in.
Powerplant: One Daimler Benz DB 603 L twelve-cylinder, inverted Vee, liquid-cooled in-line engine rated at 2,100 h.p. for take-off.
Weights: Empty 9,058 lb. Loaded 1 1,025 lb. Maximum loaded 12,125 lb.
Performance: Maximum speed 339 m.p.h. at sea level, 350
m.p.h. with MW-50, 439 m.p.h. at 37,000 ft., 463 m.p.h. with MW-50. Service ceiling 40,350 ft.

FOCKE WULF Ta 152 H-1
Dimensions: Span 47 ft. 6 in. Length 35 ft. 5 in.
Powerplant: One Junkers Jumo 213 E/B twelve-cylinder, inverted Vee, liquid-cooled in-line engine rated at 1,880 h.p. at sea level and 2,250 h.p. with MVV-50 water-methanol injection.
Weights: Loaded 10,472 lb. Maximum loaded 11,508 lb.
Performance: Maximum speed 431 m.p.h. at 35,000 ft;
465 m.p.h. at 30,000 ft. with MVV-50 and 472 m.p.h. at
41,000 ft. with GM-I and MVV-50.