Thoughts on the Nakajima Ki-84 and Kawasaki Ki-100

[Shortround6]

That is correct.

SR6,

If I understand you correctly, the higher the compression a motor has, the less boost it can take (it's by default of higher compression already near it's max capability)? That sounds correct as I have read if you want to turbo or supercharge a motor the compression ratio is usually lowered.

Cheers,
Biff

If you are, for illustration's sake using a 7.0 compression ratio and 45in (roughly 1.5 normal air pressure) you have an effective compression ratio of 10.5 in the cylinder compared to a non-supercharged engine. It is actually higher than that as non-supercharged engines very rarely run even 30in of pressure in the intake manifolds, they are usually in high 20s due to throttle restrictions and airflow friction losses in the manifold. On a non-supercharged engine the "pressure gauge" is sometimes called a vacuum gauge.

A non supercharged engine might be able to stand a mild amount of supercharging but to really take advantage of the supercharger the compression ratio usually has to be lowered.
Again this has as much to do with heat as it does with the octane rating of the fuel. if you use 7.5lb boost (roughly 45 in) you are burning roughly 50% more fuel per minute in the cylinder/s.

 

[Ivan1GFP]

SR6,

If I understand you correctly, the higher the compression a motor has, the less boost it can take (it's by default of higher compression already near it's max capability)? That sounds correct as I have read if you want to turbo or supercharge a motor the compression ratio is usually lowered.

Cheers,
Biff

Hello BiffF15,
I believe your idea is pretty much correct.
The complete answer gets a touch more complicated than that.
Shortround6 mentioned valve / port opening in passing but a bit more of an explanation might be in order here.
There is mechanical compression. This is the 8.0:1 or 6.7 to 1 number that was mentioned for Homare versus R-2800.
The rest of the story is volumetric efficiency (airflow) as determined by other factors such as manifold runner restrictions, valve timing and overlap and even exhaust scavenging (Think headers on a car).
This kind of messy thing is why on a Daimler Benz engine, you have different mechanical compression ratios on each bank of cylinders (!). Apparently the location of the supercharger and intake issues (or something, perhaps some German Gremlins) mean that the actual airflow in each bank is equal even though the mechanical compression is not.

There is also the issue of keeping the combustion chambers cool such as with reverse flow cooling on an auto engine or an intercooler on a supercharged engine that allows higher compression or boost.

- Ivan.

 

[taly01]

In the WWII sims I have flown, including some of the best, the performance was never all that realistic.

Its for this reason I never played computer car racing sims, as it doesn't feel like driving a car at all, although i appreciate what they try. As i've never flown planes I do not know just how fake computer flight sims are
Still flightsims can simulate the relative performance of planes to be useful, ie. try flying an A6M2 vs a F4U-1 and you quickly see how the difference in speed and turn performance dictates tactics.

I made a flight model for the il2:1946 Ki-100 that matches its book climb & speed, 590kph@6000m WEP speed (standard il2 Ki100 max. is only 555kph@6000m), cause I want to see if it performs up to the hype, even if only in a simulator!

My take on the Ki-100 is that it has a low drag wing and can turn without badly bleeding speed, and its strongly made for high dive speeds & turns, so was able to compete vs Mustangs.

 

[Ivan1GFP]

Hello Taly01,
Glad to see you here. I figure you know at least as much about editing flight models as I do.
The problem is that a lot of times there is serious conflicting information such as with the roll rate of the A6M series.
If you read the books by Captain Eric Brown, you will figure that A6M had a pretty mediocre roll at best.
That is how I originally built my own flight model for the A6M2.
If you watch a few videos and modern pilot interviews (you-tube) you gather a totally different impression at least for the A6M5 which probably applies to earlier aircraft to some extent as well. The roll rate at low speed is actually VERY good. Just watch the videos with a stopwatch handy.
Folks also argue the heck out of how much the controls lock up at high speed. I have seen discussions lasting several pages with each side quoting a different pilot account for the same basic aeroplane. So which is right? Author of the flight model has to make a best guess and usually the author isn't goting to get the chance to fly the A6M to find out.

The other thing a simulator gives you the opportunity to do is to fly the wartime aircraft as they were originally configure with thousands of pounds of armour and armament and run the maximum power settings that would never be used on today's surviving warbirds. You also get a impression and learn to read Japanese cockpit instruments instead of the modern instruments in today's survivors. I still wonder how pilots figured out their boost settings when the instruments would not read that high!

You can also try out a few Kamikaze dives to see how the A6M controls locked up to make accurate piloting difficult when diving or perhaps take a P-38 or P-47 into a Compressibility dive and recovery..... or not and see what works and do it a few dozen times and go have Lunch afterwards.

Sometimes a mistake also gives you a little revelation. I was working on a flight model once and forgot to alter the area of the Horizontal Stabilizer. Everything was just fine in terms of handling and flight performance from what I could tell until I took it for a test of Service Ceiling. At high altitude the stability reduction and difficulty holding attitude showed up an unacceptable problem which traced back to the area difference. It gave some pretty good reinforcement.
I don't think this kind of testing will ever be done by people flying the surviving aeroplanes today.
Of course service ceiling tests also typically end with a test for terminal velocity to Lawn Dart.

- Ivan.

 

[special ed]

The only flight sim I ever used was Sierra Pro Pilot designed for Windows 95. I installed it on my 98SE back in the day and had the joystick with all functions except brakes which required one to press ALT+ P on the keyboard. The four aircraft available were Cessna 172R, Bonanza V35, King Air 200, and Citation 525. This was a good program which had complete ground school, check lists, and how to file flight plan. I picked this up at a computer store from their close out rack. Since I had soloed a C.150 and had stick time on other types with friends, I thought this might be fun. It was very revealing. After just a few attempts I could manage the 172 and it was very realistic. The only problem was after landing trying to find the brakes on the keyboard. It always kept on off the end of the runway. I was never successful with the others. The ground scenery was accurate for southern California, as well as wherever one chose to fly, and on take off in the Citation I always crashed into the mountains. The advanced twins required proper use of the nav features and radio procedures which I didn't have. My flying buddy who had land & sea, multi, instrument, glider and instructor tickets, flew the King Air to St. Louis. He could fly the Citation like a fighter and often buzzed the tower and flew between hangars, something he obviously could never do in real time. When he was flying the sim, I had to be the co-pilot only to use the brakes after landing. This thread brought back much fun.

 

[Vincenzo]

I've Microsoft Flight Similator, i don't remember the release, i need to start already in flight or to runway, i never able to get the plane from the hangar to the runway

 

[Thumpalumpacus]

I've played many flight sims, but not being a pilot I have no way to ascertain their accuracy, and so I'm skeptical of how much they may actually teach me about the flight characteristics of the planes I've "flown".

They have, however, taught me that being ham-handed on the controls is usually a pretty bad idea.

 

[Ivan1GFP]

I've Microsoft Flight Similator, i don't remember the release, i need to start already in flight or to runway, i never able to get the plane from the hangar to the runway

Hello Vincenzo,
Perhaps it is the flight model that is broken. I found out when I was working on a Me 109E for CFS that the stock aeroplane simply could not be steered on the ground. Differential braking, propeller effects, nothing would give sufficient control.
It turned out to be a few fields in the flight model that just needed seriously modified, but up to that point, I had never heard it mentioned before.

 

[SaparotRob]

I sometimes watch sims posted on YouTube. I like the graphics. I have never noticed anyone doing the tactics I've read about. It seems like melee only. Do the armchair pilots ever try the "beam defense" or other maneuvers to see if it works for avatar aviation?

 

[Thumpalumpacus]

I sometimes watch sims posted on YouTube. I like the graphics. I have never noticed anyone doing the tactics I've read about. It seems like melee only. Do the armchair pilots ever try the "beam defense" or other maneuvers to see if it works for avatar aviation?

The AI wingmen I've played alongside are notably crappy tactically even if they're "rated" in the game as good pilots, providing little teamwork. If you design an attack well, as a flight or squadron leader, you can inflict enough kills/damage that your AI flight can then number-up against survivors and there's a semblance of teamwork, but only insofar as your subordinates are on point. But most of the time, once an encounter happens everything goes to crap. Idiots go wandering off and you see a stream of smoke and hope it's not one of your own.

I haven't done online flying with or against human opponents so I can't speak to that. I'm sure that a well-coordinated flight of four humans online would defeat a poorly-coordinated flight of even more human-piloted planes, for the lack of tactical awareness on their part.

 

[Vincenzo]

Hello Vincenzo,
Perhaps it is the flight model that is broken. I found out when I was working on a Me 109E for CFS that the stock aeroplane simply could not be steered on the ground. Differential braking, propeller effects, nothing would give sufficient control.
It turned out to be a few fields in the flight model that just needed seriously modified, but up to that point, I had never heard it mentioned before.

I ever thinked was my fault, however i googled and was MFS III

 

[BiffF15]

I haven't fought other guys online in the civilian world. However I did get roped into watching a bunch of YouTube videos by one of the guys in my crashpad who does the online gaming / fighting. We watched one where and F15 fought a F18 and lost. The guy running the video then goes on to debrief why the fight turned out the way it did. He was totally wrong. The fight was lost (by the Eagle) at the first merge, not 5 minutes later in a groveling match at the floor (where the Eagle got shot) as he stated (the YouTuber).

From watching the fights on YouTube, the one thing that stands out is they all degraded to furballs where guys just pulled and pulled regardless of their speed. The winner was usually decided by the plane whose performance allowed that style of fighting and or luck, not due to superior skill or knowledge.

There were some fights that were organized by a USN F18 guy and his buds. He did a good job of not debriefing (AKA giving info away). The comments from the peanut gallery were pretty entertaining.

For insight, read John Boyds book.

Cheers,
Biff

 

[tonycat77]

I sometimes watch sims posted on YouTube. I like the graphics. I have never noticed anyone doing the tactics I've read about. It seems like melee only. Do the armchair pilots ever try the "beam defense" or other maneuvers to see if it works for avatar aviation?

Can't speak for modern stuff (IL-2 1946 uses a 2001 base engine under it and it's the most my college notebook can run at the moment)
But i do use the weave a lot in campaigns, usually i just use the AI companions as bait for other planes to dive into, then i just slide behind them.
I do like the random aspect of it sometimes, most of the missions are generated randomly and probably not very historical but it still fun.
sure the flight model is probably 100% real, but what of it?

I can still outclimb yaks and dive back on them with my me-109F like i read they did, i can still get shotdown by trying to fly a p-51 at low altitude and low speed, i can still try to fly a dutch brewster against waves and waves of oscars in Malaysia, etc.
Simulations will never be the real deal, i don't have to deal with logistics, tiredness, weather, fear of dying, etc..
But in the end it's not supposed to be.
I suggest you guys at least try.
A microsoft force feedback 2 (one of the best and most durable flightstick ever made) are around 40-60$ on Ebay, or you can get a full kit from thrustmaster with rudder and a throttle, brand new for around 200$.
I can promise, you guys will have a lot of fun

 

[GregP]

Hi Biff,

I think most flight sim gamers just pull and pull because, otherwise, they cannot keep their opponents in sight / in-screen. Most do NOT know how to operate the radar / HUD / whatever it takes to keep situational awareness. If they lose someone off of the screen, they are just lost and don't know how to find them again without just turning endlessly. No so in a real fighter.

Most have also not studied BFM, and so don't really know what to do, so they go with what works the best for them.

I could easily be mistaken here in thinking that. If so, let me know.

 

[SaparotRob]

I've seen team play but no tactics. Just wondered if anyone tried it.

 

[Ivan1GFP]

Hi Biff,

I think most flight sim gamers just pull and pull because, otherwise, they cannot keep their opponents in sight / in-screen. Most do NOT know how to operate the radar / HUD / whatever it takes to keep situational awareness. If they lose someone off of the screen, they are just lost and don't know how to find them again without just turning endlessly. No so in a real fighter.

Most have also not studied BFM, and so don't really know what to do, so they go with what works the best for them.

I could easily be mistaken here in thinking that. If so, let me know.

Hello GregP,
I believe for the most part, you are correct. Technology these days has made things just a touch closer though there still isn't the 180 degrees of peripheral vision that most people have. Look for something called TrackIR. I personally don't have it but it is available.
A few years back, I had a head to head setup with two gaming PCs in my living room.
Because I was doing a lot of development of visual models, I needed to be able to see what the other guy saw in online play and there was no other easy way to do it. They were connected by 56K baud serial line with Null Modem. I encouraged my children to play against each other. That is how they got their aliases Rat1 and Rat2. Those were their callsigns in the game.

As for vision, nothing comes close to a moving head and peripheral vision, but I had pretty decent views programmed into the joystick (Microsoft SideWinder Precision Pro). The Hat Switch gave 8 directions of horizontal view. When the shift button was hit, that gave 8 directions at 45 degrees Up. A separate button gave a view directly overhead.
The switching and scanning was pretty intuitive because the directions made sense, but when the target happened to be at the edge or two screens, it was still visible but easy to miss.
It was always possible to zoom out slightly for better overlap of screens, but then the precision for shooting was not as good.
For a time, those Precision Pro joysticks were very easy to find used and quite inexpensive. I probably have at least a half dozen of them still and have given away a couple. The problem is that they work off a MIDI port and those are a lot harder to find on modern PCs. The Precision 2 joysticks work off USB but have lost the shift button for the 45 degree up views, so for "Combat" flying, they are not nearly as good. I still have not figured out a more modern solution that is as intuitive.

This head to head setup was how I was able to determine the settings for "Collision Bubbles" to use for my models.
For collision detection, each aircraft has a radius (yeah, they are flying balls!) that if something enters, both aircraft explode. When flying in game, things happen so fast so things are very hard to capture and measure and certainly not repeatable with any reliability. I tested by landing both aircraft and taxiing one toward the other 1 meter at a time as I got close and see what the distance was when the Kaboom happened. The result was a compromise because there was no distinction between vertical and horizontal separation and watching wing tips overlap was strange but it beat the heck out of guessing which is what other folks I knew were doing.
Thus I was able to alter the collision detection within the models I was distributing rather than require a change in game settings such as collision detection timing as was one alternate solution.

 

[BiffF15]

Hi Biff,

I think most flight sim gamers just pull and pull because, otherwise, they cannot keep their opponents in sight / in-screen. Most do NOT know how to operate the radar / HUD / whatever it takes to keep situational awareness. If they lose someone off of the screen, they are just lost and don't know how to find them again without just turning endlessly. No so in a real fighter.

Most have also not studied BFM, and so don't really know what to do, so they go with what works the best for them.

I could easily be mistaken here in thinking that. If so, let me know.

Greg,

I think you are spot on. I've played IL-2 and enjoyed it, but IIRC it had several modes of visual beyond looking only through the front window. In real life guys also tend to pull of airspeed more easily as a FNG. You can't employ the gun unless you are pointing pretty much at someone, and the older missiles required your nose to be close (it's tough for them to hack the turn when a target is close - small wings and lots speed = not maneuverable). Missiles generally get it done do to being so much faster than the target (it can't get out of the way).

Cheers,
Biff

 

[Thumpalumpacus]

Hi Biff,

I think most flight sim gamers just pull and pull because, otherwise, they cannot keep their opponents in sight / in-screen. Most do NOT know how to operate the radar / HUD / whatever it takes to keep situational awareness. If they lose someone off of the screen, they are just lost and don't know how to find them again without just turning endlessly. No so in a real fighter.

Most have also not studied BFM, and so don't really know what to do, so they go with what works the best for them.

I could easily be mistaken here in thinking that. If so, let me know.

Learning how to anticipate a target's maneuvers was a turning point in my ability to successfully fight in a sim. Since most of the sims I've played were WWII (with one WWI), there were no HUDs or radars, getting a joystick with a hat-switch was important.

After that, the next big hurdle was understanding my a/c's strengths and weaknesses vs the enemy's capabilities so that I could plan my tactics coherently.

One good thing about Red Baron II was that the manual had a good section on BFM as well as ACM.

After all that, it was on me to learn how to string BFM, ACM, and tactics together in order to first stay alive, and then gain tactical advantage for the kill where possible.

 

[Clayton Magnet]

I think most flight sim gamers just pull and pull because, otherwise, they cannot keep their opponents in sight / in-screen

Modern flight sims generally support head tracking hardware/software like Track IR. All the guy has to do to keep the opponent in sight is move his head.


Or better yet, they use a VR headset

 

[Dimlee]

Its for this reason I never played computer car racing sims, as it doesn't feel like driving a car at all, although i appreciate what they try. As i've never flown planes I do not know just how fake computer flight sims are
Still flightsims can simulate the relative performance of planes to be useful, ie. try flying an A6M2 vs a F4U-1 and you quickly see how the difference in speed and turn performance dictates tactics.

I made a flight model for the il2:1946 Ki-100 that matches its book climb & speed, 590kph@6000m WEP speed (standard il2 Ki100 max. is only 555kph@6000m), cause I want to see if it performs up to the hype, even if only in a simulator!

My take on the Ki-100 is that it has a low drag wing and can turn without badly bleeding speed, and its strongly made for high dive speeds & turns, so was able to compete vs Mustangs.

Was your Ki-100 model included in some Il2 1946 mods or mod packs? BAT?