Wing42 Lockheed Vega 5 - Update to 0.04

[YoYo]

Had a crash landing a few days ago. I think some trouble with the oil pump, the engine suddenly stopped. Oil warning lamp was on. Now my fuel tanks are permanently leaking. Vitus, we need a repair option for the fuselage...

Ask Jack's from maintenance hangar .

 

[Yossarian1943]

Ask Jack's from maintenance hangar .

Asked him, but he told me that he is not qualified enough.

 

[warchild]

MAN have you guys really got me going on this one. Over the years I've seen some amazing aircraft produced and even helped make some myself, but those were mostly military aircraft or big tubeliners. Either bare bones or so much there you need a second person.. I'm a creature of comfort. I enjoy a quiet bowl from an old Czech pipe while reading a good book or simply daydreaming in my favorite chair. I like rich woods and glistening metal, and all the trappings of a well thought out machine. The Beech 17 was one of those. I loved that plane, and now you guys come along with this monstrosity resplendent in perfectly stained wood panels with Ash ribs and gleaming copper and brass vaccum tubing. Beech 17! Its time to move over. Theres a new kid on the block and its looking a lot like home..

 

[Vitus]

Hi guys,
Sorry for coming late to the party. I'm incredibly busy with the September update. This update is HUGE and it will finally push the Vega to the study-level state I want it to be. To give you some idea what I'm talking about:

The Vega's engine will be simulated in two different regimes. A "slow" regime will be active if the engine's speed is less than 30 rpm, the "fast" regime is active for anything above that. In the slow regime the Prop-o-Tronic physics engine calculates the position of each cylinder's intake and exhaust valve, the position of the pistons, pressures, temperatures, ratios and mass of the charges in each cylinder, timing of the ignition etc.etc. I'm yet to find a good way to present this data in the sim, but there's a loooooot going on under the hood.

The next update will also replace the direct-drive starter motor with the more common Eclipse inertia starter. This means that electrical failures due to the overload of the starter motor should become more rare.

Right now I'm working on the NA-Y7B carburetor. I will simulate the level in each of the two barrels, the position of the floats and how it affects the needle's position. After that I move to the calculation of pressures at the air-scoop, choke point and manifold and based on the barrels' condition work out the mixture of the charge that enters the cylinders.

It's still a lot of work and I don't have much time to finish it up...




I wanted to answer some of your posts, but I thought I first let you know WHY I'm not very present in this thread at the moment.

First off, thanks for the wonderful screenshots, they look absolutely gorgeous!

@Yossarian1943:
The oil system doesn't impact the fuel consumption of the Vega. My guess is that you opened the fuel dump valve which slowly drains the fuel out of your selected tank(s). You'll find the valve directly under the wobble pump on the right side of the cockpit.

@warchild:
I'm glad you're hooked and welcome on board!
It's an interesting comparison you draw between the Vega and the Staggerwing. Technology advanced quite rapidly in these times and these two aircraft illustrate this very well. The Vega is prettier though




Btw: if you haven't seen it yet, you can currently vote on the next two liveries for the Vega over here.

 

[YoYo]

Hi Vitus,

thx for this update of info. I know, near every part is working here. When I checked LVAR functions I noticed that every part of engine, every cylinder has own parameters, temperatures, ect. Awesome, simply.
Is it any expected date for update?

 

[Vitus]

I'm aiming for the end of September, but I'm not sure if I can deliver on time, if not it'll be early next month.

 

[YoYo]

Btw. next skins for next update (winers of the poll):

 

[YoYo]

New shots from incoming update (and new 3D model!) :

 

[dvj]

New shots from incoming update (and new 3D model!) :

OooooH Yeah! Now that's a beauty. Can't wait.

 

[manfredc3]

Looking forward to the update, even though I am enjoying the current version already a lot.

 

[dvj]

Found this reference to the aircraft above.

https://grandcentralairterminal.org/airplanes/NC624E/index.php

 

[Vitus]

There's some really cool stuff coming with this update. The sound engine for all cockpit sounds, new inertia starter, a new 3d model for the TWA, an innovative engine simulation with functional spark advance, proper mixture controls, highly detailed carburetor simulation, etc.

I'm so excited to showcase all the features. Unfortunately, I still have many loose ends to tie up. I'm working my arse off to get everything done by the end of the month.

I have soooooooooooooooo much to talk about when it comes to the system simulation of this aircraft, but I don't find the time for it yet.

To give you an insight into my work, check out what my whiteboard looks like today:

I'm engineering the s**t out of this aircraft!

 

[Sundog]

That whiteboard reminds me of my time back in college. I was looking for the graph of Fanno line flow on that board, lol.

 

[YoYo]

Otmar,
I really very like Your Approach to all subjects !

 

[Vitus]

Otmar,
I really very like Your Approach to all subjects !

Thanks man! I'm glad you enjoy the work. I honestly wish I had more time to communicate more of what I'm doing, but I'm still desperately trying to keep a schedule

That whiteboard reminds me of my time back in college. I was looking for the graph of Fanno line flow on that board, lol.

A lot of what I do in regards to the Vega takes me back to uni too. But the approach is a bit more pragmatic than the problem solving in thermodynamic classes. I usually try to visualize the function of a component I'd like to simulate (in this case the carburetor and cylinders of the engine) and think of the different parameters and variables needed to describe the process. Next, I try to produce algorithms to sufficiently model the process. For example the simulation of the lubrication system is heavily leaning on the Darcy-Weissenbach formula. But in many cases I try to find ways to simplify the formulas in order to optimize the process. An example for that is that I assume the fuel-air mixture in the carburetor to behave like an ideal gas, ignoring the different compression rates of the mediums. All of this has to run in real-time after all!

Gosh, Fanno didn't even occur to me! But I recon that it would be too computation-heavy to be used in real-time for the engine simulation anyway!?

What I really enjoy about this process is the little details that can be put into the calculation model. For example, the NA-Y7B carburetor of the Vega is using what they called an "combined economizer and acceleration pump". In my simplified diagram that is the spring mechanism left of the float. The problem it solves is the following: the float of the carburetor is used to meter the fuel injected into the air stream of the intake manifold. The float in this barrel is connected to a needle valve, that means that when the fuel level in the barrel drops, the float sinks down, opening the needle valve letting in more fuel -> the float rises again, slowly closing the valve again. The float mechanism essentially keeps the fuel level constant in the barrel no matter how much fuel gets sucked through the discharge nozzle. Buuuuuut: when the pilot opens the throttle very swiftly, the fuel in the barrel will sink extremely fast, because it takes a few milliseconds for the float and valve to react to the new condition. This could lead to the engine being deprived off fuel, because the mixture gets too lean. The only solution for the pilot would've been to increase the throttle very slowly.

But here comes the clever engineers of Bendix Stromberg with their acceleration pump! With such a system installed (as it is in the NA-Y7B), the throttle is also linked up to a spring-loaded plunger that sits inside the barrel. When you increase the throttle quickly now, this plunger gets pushed down, discharging a large amount of fuel directly into the air stream. The spring on the other hand automatically resets the plunger over time, even while the throttle lever is still in the full-open position!

It's a really nifty mechanical system and I'm honestly in awe for the ingenuity of these mechanical engine components of the 20s!

The way the mixture is regulated is also very interesting, but I think I leave that part for the manual of the Vega

 

[dvj]

Thanks man! I'm glad you enjoy the work. I honestly wish I had more time to communicate more of what I'm doing, but I'm still desperately trying to keep a schedule



A lot of what I do in regards to the Vega takes me back to uni too. But the approach is a bit more pragmatic than the problem solving in thermodynamic classes. I usually try to visualize the function of a component I'd like to simulate (in this case the carburetor and cylinders of the engine) and think of the different parameters and variables needed to describe the process. Next, I try to produce algorithms to sufficiently model the process. For example the simulation of the lubrication system is heavily leaning on the Darcy-Weissenbach formula. But in many cases I try to find ways to simplify the formulas in order to optimize the process. An example for that is that I assume the fuel-air mixture in the carburetor to behave like an ideal gas, ignoring the different compression rates of the mediums. All of this has to run in real-time after all!

Gosh, Fanno didn't even occur to me! But I recon that it would be too computation-heavy to be used in real-time for the engine simulation anyway!?

What I really enjoy about this process is the little details that can be put into the calculation model. For example, the NA-Y7B carburetor of the Vega is using what they called an "combined economizer and acceleration pump". In my simplified diagram that is the spring mechanism left of the float. The problem it solves is the following: the float of the carburetor is used to meter the fuel injected into the air stream of the intake manifold. The float in this barrel is connected to a needle valve, that means that when the fuel level in the barrel drops, the float sinks down, opening the needle valve letting in more fuel -> the float rises again, slowly closing the valve again. The float mechanism essentially keeps the fuel level constant in the barrel no matter how much fuel gets sucked through the discharge nozzle. Buuuuuut: when the pilot opens the throttle very swiftly, the fuel in the barrel will sink extremely fast, because it takes a few milliseconds for the float and valve to react to the new condition. This could lead to the engine being deprived off fuel, because the mixture gets too lean. The only solution for the pilot would've been to increase the throttle very slowly.

But here comes the clever engineers of Bendix Stromberg with their acceleration pump! With such a system installed (as it is in the NA-Y7B), the throttle is also linked up to a spring-loaded plunger that sits inside the barrel. When you increase the throttle quickly now, this plunger gets pushed down, discharging a large amount of fuel directly into the air stream. The spring on the other hand automatically resets the plunger over time, even while the throttle lever is still in the full-open position!

It's a really nifty mechanical system and I'm honestly in awe for the ingenuity of these mechanical engine components of the 20s!

The way the mixture is regulated is also very interesting, but I think I leave that part for the manual of the Vega

Professional work, but what would I actually experience in the sim with these fine engine simulation nuances? -d

 

[Vitus]

Professional work, but what would I actually experience in the sim with these fine engine simulation nuances? -d

Fair question. My goal is for the Vega to become a study-level aircraft. Simulating individual components to the extend that I do, allows me to to generate more realistic behaviors. I.e. Failures of components, power losses due to maltreatment or exterior conditions, etc. Making it a more immersive and realistic experience.

 

[JohnC]

This is an ambitious and impressive project. I took her out for a brief flight this weekend and thoroughly enjoyed the experience. Had a minor head-scratching moment when the starter motor blew, then lo and behold the fuse had also melted and needed to be replaced. First time that I've ever functionally interacted with a fuse on a simulated aircraft, and it was a natural (intuitive) progression in the problem solving chain.

 

[speedy70]

Such a shame to see the wing42 site now.

It looks like something has happened to the product or rather to Otmar the owner and developer of the Vega.

Nothing has been heard since the middle of September and the site is being spammed by many spammers.

It is really very sad.

Otmar if you need any help ask here on SOH,I am sure there are many of us who could help.

Cheers Chris

 

[dvj]

The site seems to be working ok. You can still place an order.

-d