Heinkel He-162 "Spatz", 1944

[aleatorylamp]

Hello Ivan,

Thank you for your detailed post - that will take some studying time - but we know there´s no hurry.
There are a few points in there that I have to look into in depth, to be able to understand them first, and to apply them afterwards!

Graph Table 430... Oh! Abstract art, but at least not as complicated as the 2 propeller tables!
So the latest adjustments on the Sparrow´s speeds are possibly not good enough yet... I thought I´d got them better...


Hello Hubbabubba! Re. your post #38.

When I saw the blue "HERE" referring to the little gem, I saw the big picture of the instrument and took it to be that!
Now I realize it´s a link to THE German manual. Oh dear... better late than not at all!
OK, that will take some time to study too. Thanks you very much indeed!

Cheers,
Aleatorylamp

[aleatorylamp]

Hello Ivan,

One of the advantages of your instruction details was that I now understand the workings of Induced Drag and its effects. After trying out different adjustments, I got some interesting results.
One thing is definite: Changes in the Drag value directly affect engine thrust. It would, wouddn´t it... as it affect turbine blades directly.

Objective: Still, to increase speed at altitude because of excessive power loss at altitude, which is not possible to regain by other means for lack of other available parameters.
--Increased Oswald factor to 7000, and correspondingly adjusted Zero Lift Drag.
--Tweaked Mach/Drag Table #430: lowering the "ramp" from 5 to 1, just before the Mach "wall".
--Fine adjustments made by tweaking Wing Angle of Incidence and Angle of twist.

This test got the best results so far, for maximum Boost Stim power at 100% throttle both at S.L. and at 19680 ft!
However, this time normal 9500 RPM power was slightly high at S.L. and a bit low at altitude.

Nevertheless, I have the feeling that it is quite satisfactory, given the circumstances!

S.L. performance:
At _91% throttle: _9500 RPM, 1759 flb and 503 mph (12 mph over) aim: 491 mph
At 100% throttle: 10100 RPM, 1991 flb and 536 mph (_3 mph over) aim: 553 mph

19680 ft (aka 20000 ft):
At _83% throttle: _9500 RPM, _955 flb and 497 mph (25 mph under) aim: 522 mph
At 100% throttle: 10350 RPM, 1209 flb and 562 mph (Right Bang-On!) aim: 562 mph

Interesting too, your different Rocket .air file adjustments, corrections and comments! Thanks a lot.
Compared to how other engine parameters work, once understood, the two Rocket lines are very simple, aren´t they?
I wonder if it will be possible to ever get a sound working there...

Hello Hubbabubba:
I made screenshots of all the pages in the manual, and am going through them.
I find it fascinating, how the the intial technology of the jet-age developed!

Cheers,
Aleatorylamp

[hubbabubba]

(...)
That is some very interesting additional information! Thanks very much.
I had only seen the pilot´s handbook for 30 dollars or so. Drool... Very handy for further FD adjustments. I won´t upload anything before back-checking with Ivan and yourself.


The speed limits you mention for the different heights would perhaps be under maximum continuous?

Do not use these speeds limitations in your model! As I briefly explained in my last post, they where for pilots flying from A to B, not for fighting or testing purposes. As I was testing take-off and landing, I flew according to these numbers to see if the a/c would obey in the prescribed manner. I can say that it basically did with the exception of the flaps not showing under the wings after hitting one increment (I can't push-pull my keyboard... ). Take-off and landings were pretty much "on the dot".

(...)
I can decrease Flap-deployment time. Interesting mechanism you describe!
I haven´t adjusted anything on the flaps as yet. The only effect on them in the present .air file is the overall increase in Zero Lift Drag, which affects them too.

I would decrease the flaps positions to 3 in section #315. It works like a charm in mine; pushing F7 one time lets you see the flaps just a bit, the second push gives you full flaps. As the flaps had, from the point of view of this Pilot's Handbook, only two intermediate state of deployment, take-off and full, it should be visually okay. You may have to change the flap sound by a guy pumping an old bicycle pump, or perhaps borrow the Spit flaps sound. I will now try t/o and landing with that adjustment in the AIR file to see if I can pick-up enough speed.

(...)
Sorry about the bad taxiing! I know it was mentioned a few days ago, and I looked into Steerable yes/no, and found it ON, but failed to check the rudder moment. Sorry, will fix!!
(...)
Update:
Yes, there seems to be a serious rudder problem. Rusty and seized hinges!... Although autocoordination is off and a control-surfaces gauge records rudder movement, and although the rudder moment should be OK at 178 (I increased it to 195), it still has no effect! There are quite a few parameters to do with Yaw, so it´s a bit more complicated. I´ll see what´s going on.

Just happy to see that you see it too.

(...)
So then, we could also have an additional RATO version for the Sparrow once the rest of the FD is sorted out. Fascinating! There are more than enough parts left over. Let´s see if there are no bleeds.

Mmm... not sure it is worth the trouble. That system was seldomly used as Germans always operated from long-enough airstrips until the end of hostilities. But the attachment were there, just in case...

Update 2:
Rudder and elevator control is terrible! I have used data from other planes that work, and it seems better now. The cross-effects that rudder has on roll makes it more difficult and although rudders now make the plane yaw, they end up rolllng it quite strongly even though rudder effect on roll is at zero.
Then, turning during taxiing now works, but it is very still very spongy.
What is absolutely clear, is that I am terrible at adjusting the flying characteristics of planes. Not my cup of tea by any means!!
Anyway, as soon as get the speeds better, I can post another updated .air file.

Again, no rush. The rolling on side slipping is natural and can be corrected with ailerons or return to straight flying. My AIR file for the V1 does it quite naturally, and taxi like a NY cab! Maybe you should have a look at it. Capt. Brown did warned about over-doing it though, one pilot did not listen and paid dearly.

Update 3: (...)

I think I already answered that one but, just to be clear; Do not take these numbers to build the AIR file, only for flying "according to the book". On another subject, I will use metric system because it is a "metric aircraft" and gauges and specifications are done accordingly. BTW- Germans did used knots (knotten)... in the Kriegsmarine. I'm not sure, but it would be interesting to see the Fahrtmesser of a Bf 109T.

(...)


The reason for speed differences is probably because in the Pilot's Handbook, speeds are stated in Indicated Air Speed.
The Wikipedia article appears to be pretty reliable for data. The 562 MPH at 19680 feet and 553 MPH at Sea Level are what I would go for.
Regarding poor handling, I can take a look at it in the next couple of days. Been very busy with a couple other projects (not flight simulator stuff) and also trying to figure out some discrepancies between the several installations of CFS that I have.


I am pretty sure I have an entry in Eric Brown's book on this aeroplane, but where can the pilot's handbook be found online?

I have answered for the Pilot's Manual. And, yes, these are most certainly I.A.S.. Interesting images I found;





This is the sticker in the middle, on top of the instruments. It means, I think;
"Attention!"
Pitot tube (reading) is around 10% too little
Interception (trapping?) shall not exceed 4 g
Negative acceleration no longer
than 3 sec. because otherwise engine goes out.


The third line is a bit problematic as the He 162 had no G-meter, so it must have been measured by "feelings only". The Abfangen term means mostly interception but, logically, could also mean the trapping of the gears.





This is what is on the sticker just to the right of the first one;
speed limits
Flaps take-off position Va: 500 Km
Flaps landing position Va: 300 Km
Gears down Va: 350 Km
Flight time: 30 minutes


These "limits" are also problematic. Are we talking here of "adjusted" speed to be done by the pilot (i.e. 500 Km/h on reality meaning 450 Km/h on the dial) or was these already taken into account (i.e. reading 500 Km/h meant that your "real" limit was 450 Km/h)? This is highly confusing to a pilot who has other things to do than mentally calculate what is really going on. No wonder that so many hand-painted markers are visible on the circumferences of the dials. It shows how expedient the program was.

Last night, I checked out the V1 Cruise Missile.
(...)


Speed of the V-1 was reported to be 390 MPH to about 435 MPH.
The speed of the CFS version is limited to about 430 MPH with a ground take-off because it runs out of fuel before maximum speed is reached.
With in-flight refueling, it reaches a maximum of 444 MPH at 1500 feet altitude which is a bit below its actual operational altitude.


So.... From my viewpoint, the CFS V-1 Flying Bomb other than its very short flying range is not a bad representation of the actual weapon.
One very disappointing aspect is that it has no sound files configured so other than an engine whine from inside, it is completely silent.


- Ivan.

My own "flyable" V1 does just under 400 MPH, speed varying with altitude. AAC members were complaining that it was impossible to intercept, some saying it was too fast, with Spitfires and P-51. After explaining how to intercept, they had a ball! The trick is to dive on them from higher altitude in a timely fashion. The original AIR file is for a rocket, but mine is for a jet as the FZG 76 was a pulsejet.

(...)


Interesting too, are your findings and deductions on the V1.
I had the feeling it was quite good too, except for the fact that a take-off run is very slow for the lack of a powered catapult. Incidentally, I wonder if it is easy enough to use the CFS1 Scenery Editor to place some launching ramps for somewhere to practise.


(...)
OK then! Cheers,
Aleatorylamp

I think I will send you both a sample of my own V1 and ramp sceneries so you could see (and have a bit of fun while doing it).

(...)
Incidentally, I saw a variant planned on the V1: The Reichenbach, a manned version of the V1, a German Ohka! This had a crude cabin just infront of and below the pulse-jet air-intake. It entailed the pilot flying to the target with crude controls and instruments, aiming the bomb at the target in a dive, and then trying to open the canopy to bail out. Probability of his survival, however, was extremely low, and the idea did not appeal too much to the Germans!


Nevertheless, the cheap simplicity of such a single-seater jet does have its appeal - Of course it would get a little more expensive with a landing-gear and sound-proofing, and a launching ramp in the back garden, but we could be off on a short sight-seeing spin around the countryside and then land in a field!
(...)

Baaad idea it was! Imagine the reception a pilot miraculously surviving would have received from the surviving neighbors...

Trying to catch-up, are you sleeping sometimes?

Hubbabubba

[hubbabubba]

(...)
V1: OK, I didn´t know it could go up to 250 mi. The range info I´d found stated only 150, so I calculated the "ETA" for 150 miles at 400 mph to be 37.5 minutes.
(...)

Maximum range was 250 Km, not miles, this is what my documentation and Wikipedia say.

Yes, be it jet of rocket, both .air files do seem to be FS98 jobs. Also, I haven´t found any information as regards what kind of sound works for rockets. I suppose the Rocket .air file would be the simplest of all - it isn´t even altitude dependent, as liquid or solid rocket fuel don´t need air to burn. Apparently rockets even increase their power with altitude - by 10% at 40000 ft because of the lower air resistance for the exhaust. Moreover, apparently nobody uses the FS rocket .air file - the Jet-turbine .air file is preferred despite all its inaccuracies.

My rocket does have sounds. And there is one in the main sound folder (named v1.wav).

Good grief! It´s 10 to 3 a.m. - I´m off to bed. We´d been out for a drink and a hamburger with chips to celebrate my younger daughter´s 20th birthday.

You go to bed before I really start my shift. I'm a night owl, always have been, always will.

I have managed to adjust several parameters to improve yaw, sideslip, and general stability, but this needs further testing, for which I am not qualified, and would appreciate your opinions again as soon as I post the next test .air file.
I do hope it´s not getting heavy on you, all this testing!

I leave the hard part to Ivan, that's my secret... ooops!

Anyhow, for the moment, I will bother you with just a few comments and one question, so here goes:


Previous results of the last uploaded .air file:
-S.L. normal max. speed perfect at 491 mph.
-S.L. Boost-Burst: 38 mph under at 515 mph.
-20000 ft, normal max. speed was 22 mph slow at 500 mph.
-20000 ft, Boost-Burst speed was 29 mph slow at 533 mph.

Out of curiosity, what you describe as "boost-burst" is the WEP?

After a small Zero Lift Drag reduction to balance out S.L. and Altitude speeds, predictably, a small increment in thrust
was caused - about 60 flb - but the speeds are much better.


(...)


So the question is:
Is it better to reduce the 60 flb excess thrust, although it will involve further reduction of Zero Lift Drag, which in turn will increase the gliding ability? At the moment Zero Lift Drag is at 42 in AirEd, which is still just about good enough to slow down the plane when flying in idle.


(...)

My take has always been to favor results over AIR file "correctness". Otherwise, the ships and the jeep would never had existed, period. I don't like the expression "garbage in, garbage out", especially in the context of a very imperfet CFS1 AIR file.

Hello Hubbabubba, Aleatorylamp,


After my prior post, I decided to go read the chapter on the He 162 in Eric Brown's "Wings of the Luftwaffe".
From that chapter, I believe there is sufficient information to have a relatively good target for a flight model.
The aeroplane apparently was not terribly sturdy and structural failures claimed the lives of two test pilots.
The Heinkel pilot died when one wing de-laminated.
The RAF pilot died when he used the rudder to yaw the aeroplane too much (rudder was apparently very sensitive) and the aerodynamic forces first broke off the tailplane and then the entire tail section and the aeroplane tumbled and crashed.


Also from the sounds of it, the aeroplane did NOT have a steerable nose wheel because brakes were needed for ground handling.
Ground handling was also noted as being poor which is another suggestion that the nose wheel was not steerable.


- Ivan.

This is one book I wish I had. Add to the precipitation, the constant changes and the sabotage that forced labor did whenever they had a chance (don't get me wrong, I would have done the same) and some of these aircraft were deathtraps. Flying one was like Russian roulette. Much more than two test pilots died flying it. If you have a chance, go see that video;



Worth notice is the fact that these young man flew these aircraft without ejectable seats and unarmed, only to be installed at the front bases. It lead me to believe that the A-1/A-2 distinction was quite academic as final decision was there, not at the assembly line.


If the front wheel was not steerable, was it, at least, castoring? I'm asking because, if fixed, it would have been next to impossible to taxi on its own, the lateal forces on that front leg would have snapped it. The Me 262, in its tricycle version, also had a very weak front gear leg, but it could at least castor with it.

(...)
Hello Hubbabubba! Re. your post #38.


When I saw the blue "HERE" referring to the little gem, I saw the big picture of the instrument and took it to be that!
Now I realize it´s a link to THE German manual. Oh dear... better late than not at all!
OK, that will take some time to study too. Thanks you very much indeed!
(...)

Next time, I will try to be more explicit but, at least, now you have it.

Hello Hubbabubba:
I made screenshots of all the pages in the manual, and am going through them.
I find it fascinating, how the the intial technology of the jet-age developed!


Cheers,
Aleatorylamp

I did a PDF of the original (quite easy under Opera) and screen capture of Google translation (German to English). I don't know if you have any knowledge of German but, between the automatic translation and a bit of grey matter at work, I'm getting pretty good.

[aleatorylamp]

Hello Hubbabubba,

Thank you for your two very helpful and detailed posts!

I´m going to install the v1 sound then. Great - I was quite bewildered how it was possible that there wasn´t one! The simplicity of the rocket .air file has its own attractiveness - but you are right, it´s not really a rocket. It works on aspirated air and then pushes the exploding petrol out the back, so in reality it is not a real rocket and should have a jet .air file. It was the Me163 that was a real rocket, and RATO... Of course, and the Ohka too.

Thanks on the clarification on the V1 range - I made a mistake on the range because of the Miles and Kilometers.
It always happens to me. Meters and Feet catch me out all the time too.

The 3rd line on the red sign in the Sparrow´s cockpit: The word "abfangen" is a variant of the word "fangen" - "catch", and in this case means catch the plane when coming out of a dive. It seems that the negative G forces made the undercarriage drop out.

Boost Burst in the Sparrow was flat-out maximum power, full throttle, with RPM above 9500 - 10500 or even 11000, allowable for a maximum of 30 seconds.

This is indicated by the red area on the RPM meter, by which, depending on altitude, the throttle lever has to be moved to keep RPM below the maximum of 9500 RPM at all times for maximum continuous use. Apparently there was no additional lever or such like - just like on the Flight Simulator Jet. Although the concept is indeed WEP, there is no other provision for its control. At S.L., 9500 RPM is at 91% throttle, and at 20000 ft, it´s at 83%.
Maybe for use in the simulator, a settings of 90% and 80% would be more convenient... but not so exact.

As regards the speeds in the Sparrow´s .air file, I think either of the last two .air files could be quite OK.

Despite the danger in flying these death traps (logically expected sabotage by slave-labourers also crossed my mind), and the probable wariness of pilots to fly them at the limit all the time, I wonder if in the simulator one should or should not tone down speeds to try and keep a safety margin? I would be inclined not to do so, but this is of course debatable.

NOTE: What I think is possibly best, will be to choose which of the 2 last .airfiles fits better to keep speeds at max. contiuous 9500 RPM as closely as possible to specification, and let Boost Burst (WEP) be whatever results, because it was only intended for 30 seconds, and would burn out the engine if abused.

The differences in speeds are not so noticeable anyway when flying the plane. More important will be the adjusting of maneuvering abilities. Given the danger of the tail braking off, I would tend towards more dampened movements.

By the way, I teach languages, i.e. not all of them, just German and English, so I have no problem with the Pilot´s manual!
At the moment I´m teaching German a group of unemployed waiters in a government-financed programme so that they can perhaps find a job.

OK, gotta rush to work. If there is anything I have missed, I´ll post a post after lunch!

Cheers,
Aleatorylamp -- Aleatorische Lampe (!!)

[hubbabubba]

By the way, I teach languages, i.e. not all of them, just German and English, so I have no problem with the Pilot´s manual!
At the moment I´m teaching German a group of unemployed waiters in a government-financed programme so that they can perhaps find a job.

Given your real name, I thought so...
Incidentally, it was also Eric Melrose Brown first job; he was teaching English in a German school when hostilities started.

[aleatorylamp]

Hello Hubbabubba, Hello Ivan,

It seems that more than one language teacher ends up flying, if not buiding airplanes, even if only virtually. It this is good or not, is quite another matter!

After bending the atmosphere to try and fit the flying envelope, things are still confusing, and maybe more than that is amiss.
Perhaps the turbojet itself needs revising, and I´m going to check the workings of the engine RPM instrument I have, which comes from the output turbine N2 gauge on the Bell Helicopter rotor.

BMW OO3 Turbine specs state Max-Continuous power as being 1760 flb at 9500 RPM, which I had established at 95%.
Additionally, 30-second Extra Boost is possible upto 11000 RPM, but my engine only goes up to 10500 RPM, this may need revising. This could possibly be the reason that Sparrow´s max-continuous and Boost-burst performance won´t tally.

Let´s see....

More, later.

Update:
Searching for additional data, I have found several sources relative to this turbojet and also to the aircraft, that however do not make any reference whatsoever to any kind of boost burst power.
There does seem to have been a single prototype involving a liquid-fuel rocket motor added to the rear of turbojet, which could be used to supply additional bursts of about power of short duration.
What must have happened, is that information on this version (003R) had somehow found its way into the general description of the aircraft and its engine, and has possibly erronously been combined there.
If this is confirmed, it will solve the puzzle of the problematic balancing of power/performance numbers of the model.
The additional rocket supplied far more power than a momentary 10 or 15% RPM increase could ever have managed.

Update 2 - So the riddle is probably solved:
This would explain the speeds mentioned by Ivan and in the pilot´s manual whose link Hubbabubba had kindly supplied.
In both there is a complete absence of any speeds above 700 or 750 kph (434 and 466 mph).
Hence, the 553 mph (890 kph) at low altitude, and 562 mph (904 kph) at 6000 metres, achieved under boost-burst can only mean what was achieved with the added rocket - which incidentally developed 2700 flb - in total power was more than duplicated!
So there was no boost burst in the production-version of the Sparrow! The pilot manual only refers to a higher warming-up RPM on startup, that can reach 9800 for 2 minutes.
So effectively, I will try to set up the Engine parameters in the .air file to deliver 1760 flb at 9500 PM at 100% throttle once the engine is warmed up.

Cheers,
Aleatorylamp
P.S. I´m still wondering how correct all these deductions could be...

[hubbabubba]

Hello Hubbabubba, Hello Ivan,

It seems that more than one language teacher ends up flying, if not buiding airplanes, even if only virtually. It this is good or not, is quite another matter!

After bending the atmosphere to try and fit the flying envelope, things are still confusing, and maybe more than that is amiss.
Perhaps the turbojet itself needs revising, and I´m going to check the workings of the engine RPM instrument I have, which comes from the output turbine N2 gauge on the Bell Helicopter rotor.

BMW OO3 Turbine specs state Max-Continuous power as being 1760 flb at 9500 RPM, which I had established at 95%.
Additionally, 30-second Extra Boost is possible upto 11000 RPM, but my engine only goes up to 10500 RPM, this may need revising. This could possibly be the reason that Sparrow´s max-continuous and Boost-burst performance won´t tally.

Let´s see....

More, later.

Update:
Searching for additional data, I have found several sources relative to this turbojet and also to the aircraft, that however do not make any reference whatsoever to any kind of boost burst power.
There does seem to have been a single prototype involving a liquid-fuel rocket motor added to the rear of turbojet, which could be used to supply additional bursts of about power of short duration.
What must have happened, is that information on this version (003R) had somehow found its way into the general description of the aircraft and its engine, and has possibly erronously been combined there.
If this is confirmed, it will solve the puzzle of the problematic balancing of power/performance numbers of the model.
The additional rocket supplied far more power than a momentary 10 or 15% RPM increase could ever have managed.

Update 2 - So the riddle is probably solved:
This would explain the speeds mentioned by Ivan and in the pilot´s manual whose link Hubbabubba had kindly supplied.
In both there is a complete absence of any speeds above 700 or 750 kph (434 and 466 mph).
Hence, the 553 mph (890 kph) at low altitude, and 562 mph (904 kph) at 6000 metres, achieved under boost-burst can only mean what was achieved with the added rocket - which incidentally developed 2700 flb - in total power was more than duplicated!
So there was no boost burst in the production-version of the Sparrow! The pilot manual only refers to a higher warming-up RPM on startup, that can reach 9800 for 2 minutes.
So effectively, I will try to set up the Engine parameters in the .air file to deliver 1760 flb at 9500 PM at 100% throttle once the engine is warmed up.

Cheers,
Aleatorylamp
P.S. I´m still wondering how correct all these deductions could be...

I'm working on a panel for your bird, Aleatorylamp, and in this process, I've found many interesting things. I will send you a preliminary version when I'm well advanced but it will be entirely up to you to decide if you want to include it in your V2 release. I too wondered about that "boosting" thing, as it was not in line with the capriciousness of jet engines of that era. Gunning an engine was usually a very good way to blow an impeller, start a fire or simply get a flame-out.

Anyway, I will send you a "teaser" of the panel soon, is it OK if I send a copy to Ivan at the same time?

Regards,
Hubbabubba

[aleatorylamp]

Hello Hubbabubba,

A new panel! Very good, that will be a great contribution, and of course, do send Ivan a copy so that we can bounce off a few ideas off him!

OK about the non-Boost-Burst then. There seems to be a confusion in the "habitual" Wikis from which some other sources obtain their info, and could account for the fact that other seemingly more specialized pages differ considerably.

I was comparing the Lear-jet engine indicating and crew alerting system (at last I found out what EICAS means) to the N2-%turbine output -come-RPM-instrument I had made, and it works fine for medium and high speeds.

With an equivalent of a maximum 95% N1 position, there is a 99-100% N2 turbine output. This definitely seems consistent.

Should any extra "over-RPM" be needed, this is also conisitent with the numbers that can be obtained above 100%, by implementing it with no problem in the .air file.

However, for CFS1 simming, I think it would make actual flying far too complicated.

BUT: What is quite off, is that the 3500 RPM idle gives 63% N2 power, which is about twice what it should be. So that has to be addressed as yet. I knew it was a bit high, but didn´t expect it to be at 63%! I will have to see how I can get to the 3500 RPM mark with the correct flb thrust.

Interestingly enough, at startup, there is automatically a slight excess power going into the "red zone" for a short time, but it is a bit higher than the 300 RPM that "your" manual describes.

OK, then, I´ll be looking forward to your panel and suggestions.

Meanwhile I´m still trying to get the plane to do 491 mph and 522 mph at 19680 ft. Even "bending the atmosphere" only helps a bit, and still has it fallling short by by 16 mph. The 0.2 Mach columns in that table don´t leave room for maneuver to "separate" the two speeds very much - they are too close. Oswald factor maipulation between 3000 and 7500 doesn´t help much either.

Anyway, we´ll get there in the end!
Cheers,
Aleatorylamp

[aleatorylamp]

Hello again,
I thought I´d investigate table #430 a little, and was surprised to find that there are just about as many different ways of setting it up as there are different types of airplanes, or even airplanes of the same type.

They all follow an overall general pattern, but have different build-ups - shallower, steeper or longer, prior to a "Mach wall", which itself may be of different shapes, heights and widths depending on the model, including different kinds of downward slopes on the other side.

I wonder which could be the best way to shape it for the Sparrow.
Maybe now that we have been able to narrow down the excessively wide and confusing performance range, this will be an easier task.

After filtering through some all-engulfing specification references we may be able to get somewhere.

I mean, look at this:

-Maximum thrust: 7.83 kN (1,760 lbf) at 9,500 rpm at sea level for take-off
-Normal, static: 6.89 kN (1,550 lbf) / 9,000 rpm / sea level
-Military flight: 6.23 kN (1,400 lbf) / 9.500 rpm / 2,500 m (8,202 ft) / 900 km/h (559 mph; 486 kn)
-Normal, flight: 2.85 kN (640 lbf) / 11,500 rpm / 11,000 m (36,089 ft) / 900 km/h (559 mph; 486 kn)
...and then:
-Maximum speed:
790 km/h (491 mph) at normal thrust at sea level and 840 km/h (522 mph) at 6000 m (19,680 ft);
-Using short burst extra thrust 890 km/h (553 mph) at sea level and 905 km/h (562 mph) at 6000 m (19,680 ft).
...Boost-Burst? How? What kind?
Why is it not mentioned in the Pilot´s Manual and several other sites?

What´s all this supposed to mean? This will throw anyone off course.

Well, perhaps it will be easier now that we have separated boost-burst from the production version.
Let´s see what we can do now.
Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp, Hubbabubba,

I am getting a bit confused with all the different approaches and conflicting data being thrown around.

In Eric Brown's description of the aeroplane in Wings of the Luftwaffe, there is a mention of the 30 second "boost" power and speed which is consistent with the 553 MPH @ SL and 562 MPH @ 6000 Meters. The other speeds are also mentioned but I don't know how much of it was just copied from a manual on the aeroplane. I doubt any of it was via actual test flight because of the unknown service condition of the captured aeroplanes. (All service histories were destroyed before capture.)

As mentioned earlier, I suspect the actual engine thrust should be much higher at 6000 Meters altitude (19685 feet) but don't know how to tune the engine to make that happen. I suspect it may not be possible with a FS98 jet engine as it is not with the FS98 reciprocating engine.
Perhaps it is time to see if there is a CFS Jet Engine which would be a bit more difficult since there isn't a stock CFS Jet to work from.

Aleatorylamp,
A couple of questions:
1. You mentioned earlier that you were changing the skin friction coefficient. How are you doing this? (where in the AIR file?)
2. You also mentioned "Bending the Atmosphere". What do you mean by that?

If you all need a custom gauge for this panel, let me know what it needs to do. I might be able to program one for you.
At this point, I CAN program SOME gauges though there are many features I still do not know how to implement.

I actually have been doing a bit more reading on the HL-10 Lifting Body and it would definitely make for an interesting model.
Before that though, I need to clear the Rocket Plane area of the workshop. The Ohka should get finished first.

Gotta Run.
- Ivan.

[papingo]

In the AF99 disk there is an .air file for a Me262 plane
but strangley no plane!!!!!
any chance of a Mig 15 or sabre to play with?
>>papingo

[aleatorylamp]

Hello Papingo,

Thanks for your suggestion - I´ll look at the Me262 .air file that comes with AF99 - I might discover something.
You´re right, there is no plane but perhaps Abacus´ intention of including the .air file was to provide a model to follow, as it were.

Hello Ivan,

Thanks for your post! By "atmosphere bending" I mean bending the graph in the Mach/Drag Table #430.
My confusion as to the correct speeds with respect to there being Boost Burst or not is based on the difficulty in getting both normal and Boost-Burst speeds to tally with the specified speeds at the two altitudes, to the extend that I was seriously doubting the reliability of the information available. Even using table #430 hasn´t helped. Speeds seem to be grouped in one or perhaps two columns, and I´m trying to sort that out, the only tool being the slope of the line.

Incidentally, the #430 table I´m using is the one that is common for a number of FS98 jet fighters and 2 rocket planes, and a glider, of all things!

I´m afraid I don´t have access to the description by Eric Brown that you mention, only to a shortened version with humorous comments in a text file I came across - this one mentions the max. level speed of 562 MPH at 18,400 ft but not a Boost-Burst.

Some sources including Wiki mention the 30-second boost burst, AND the corresponding two higher speeds mentioned for S.L. and 6000 meters, and others simply don´t. There it´s just the non boost-burst speeds, so this led me to speculate that perhaps the conflicting information was because of the fact that there was BMW 003R engine that had a 2700 flb type 718 rocket motor attatched to it, which apparently was good for fifty 3-minute boosts, and that this had mistakenly been combined into the normal model.

Well, so, from your post I deduce that my speculations were wrong, and that it DOES seems that the the BMW 003 Turbojet DID have Boost burst, and that the correct figures ARE 491 mph and 522 mph at S.L. and 6000 meters without boost burst, and 553 mph and 562 mph with.

OK, then. Like Shakespeare said, there´s "much ado about nothing"... Nevertheless, I don´t know how to get this puzzle right. Possibly a general overall approximation will be the best.
To say the least, at the moment it´s not really going very well, but I´m sure we will get there in the end.

Cheers,
Aleatorylamp

[hubbabubba]

little fact

In the AF99 disk there is an .air file for a Me262 plane
but strangley no plane!!!!!
any chance of a Mig 15 or sabre to play with?
>>papingo

I really need to check that...

[aleatorylamp]

Hello Papingo,
It´s not on the AF99 disk, but I know I´ve seen the model-less Me262 .air file somewhere.
I must see if I can track it down. Maybe it was some old FS98 add-ons disk.
Update:
There is a 1998 Me262 model by one Berndt Drehfahl (possibly publikshed on Flightsim.com) on this add-ons disk. I´m just checking it out. ...But I haven´t a clue where I saw the Me262 file without the model.

Hello Ivan,
I haven´t touched Skin Friction Coefficient. It´s on the usual -2.0 or -364, depending on the version of the AirEd.ini file.
Strangely enough, jets seem to have extremely low values for Zero Lift Drag (around 20 or 30) and also Induced Drag (Oswald, around 2000). Anyway, I was trying higher values of 7000 or so, to increase the difference between low and high altitude speeds.
Another thing I noticed on jet fighter .air files is the usually negative values for angle of incidence and angle of twist. I would have expected this to be more like zero, but the .air file seems to need it because of the strange way it calculates drag from these angles.

Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

The FS98 Me 262 by Berndt Drehfahl is still available on Simviation. I just downloaded it a couple days ago.

I will look for Skin Friction Coefficient in the AirEd.ini file.

I believe that a major part of the reason you see such strange values in the AIR file for Angle of Incidence, Twist, Wing Efficiency, etc. is because those values all interact with the CL Graph values, Angle for Minimum Drag, etc. and the values are not consistent.
Perhaps it is because some of the factors must be skewed a lot in order to make a FS98 flight model have reasonable altitude performance.

I have a few ideas what to try, but can't really state them here because the later steps depend on the results of the early steps and without knowing what comes back, I cannot predict what needs to be done next.

Regarding Record 430, the Mach Drag / Compressibility Table, I have actually been using it for years on my projects.
Because there is no way that I know of to cause a structural failure under overspeed conditions and because there usually is a terminal velocity well below the speed of sound on propeller driven aeroplanes, I use Table 430 to limit maximum dive speeds.
The Eindecker was probably the first project in which I used this technique and the A6M Type Zero is another notable example.


Hello Papingo,

Building a Sabre or MiG 15 or MiG 17 would be relatively easy as far as modelling is concerned as long as we can pin down the Jet Engine issues of power versus altitude. That MAY eventually make it onto my to-do list, but there are many other things that are higher priority that need attention first. There are still a lot of things I do not know how to do with AIR files for a Propeller plane and since that is my primary area of interest, those things take precedence.
I still have a half dozen models that have been stuck in my workshop literally for years and they have priority for now.

If anyone can point me in the correct direction for building a CFS Tachometer and a multi pointer gauge, that would get a couple of my projects finished.....

- Ivan.

[hubbabubba]

Hello Ivan,

I also found Bernd Drefahl's Me 262 in many variations at Flightsim. Haven't checked them yet.

Hello Aleatorylamp,

Also downloaded a CFS2 aircraft, he162-fm.zip, and installed the AIR file into your a/c. It worked, no problem at all, and the taxiing was very easy. But the flying was terrible, the a/c would do a half-barrel every time I went 3/4 rudder one way or the other, I had the impression of canoing in the rapids! I then dived ever so gently and went well beyond 900 Km/h from one or two km/h high. Last test I went in a zoom climb and, at around 4Km high, was standing on my tail when stall started without any notice. I still had full control of my rudders and elevator but, even by pointing the nose in the same direction of the fall, could not recuperate. Your own AIR file, the last published here, is already head n' shoulder over that one. I'm even getting used to the taxiing.

I also did a zoom climb and was able to achieve +10Km within 10 minutes or so and cruise at that altitude at around 400Km/h. Speed was still creeping up when I decided to turn back for home and land.

Concerning the "burst" method, I was under the impression that you were using the WEP (key F10) to do so. I don't even know if it could be implemented in a jet AIR file. Exploring the Musée de l'Air 360° photo display, I think this is what might be the trick;



As far as I can tell, this was the nozzle adjustment. Maybe injecting a bit more fuel by "bursts" of the toggle switch marked "Tupfen-Alassen" was the secret?

[aleatorylamp]

Hello Hubbabubba, Hello Ivan, Hello Papingo!

I looked into the Me262 specs and Berndt Drehfahl´s .air file model.
Apart from the obvious differences, and despite the same or similar engines (1706 flb BMW 003 or 1980 flb Jumo 004), the Me-262´s Jumo 004 powered flight model has a big advantage over the Sparrow´s one: There is only one specified maximum speed to go by, and no boost-burst. So, without having to work with 2 different speeds at 2 different altitudes, i.e. 4 speeds, tuning aircraft performance here is not a nightmare at all.

As per Ivan´s Table #430 explanations (thanks!), it is apparent how this table is added to the other main Drag parameter and the Drag resulting from the Wing angles. Not an easy balancing act! I am trying to pin down where the different required speeds lie. Pulling the peak up (even to 2000!!) seemed to curb higher speeds at around 566 mph, and seems to be how it can be used to limit diving speeds! Then, the 2 positions before, affected lower ones, but it was difficult to act on specific speeds of 491 and 522 mph separately because they seem to be quite close together. Different speeds in one column will need a very exact angle on the graph line!

I noticed the Sparrow´s pilot´s manual indicating something about altitude flying and also the detail on the exhaust vents, but didn´t understand it. Now Hubbabubba mentions it showing a photo, to describe how Boost-Burst worked. Good! "Tupfen" means to dab... to "dab" extra fuel for boost-burst...? "Anlassen", engine start in English, is the opposite position of this lever.

Then, the jet .air file has no provision for Key-10 WEP. Power will have to be exclusively managed by Throttle control, either the lever or the number keys 5 to 0.

After establishing that my recent doubts on Boost Burst were wrong, probably the best idea now, for the event that it may be impossible to balance out all 4 speeds correctly, would be to maintain altitude speeds and S.L. Boost speed as per specs, at the expense of having normal max. S.L. speed about somewhat faster than it should be. Would this be convenient for simming?

I´m glad that the last published Sparrow .air file is better than the previous one! As soon as I can get it any better, I´ll post the improvement. Thanks Hubbabubba, for the feedback and your good words. At least my Sparrow .air file is within generally acceptably flyable limits, which is motivating.

Anyway, thanks again for all the research work and cooperation this is generating, and it is very pleasing to see that other similar projects seem to be benefitting from it!

More, later, and meanwhile, have a nice Saturday!
Cheers,
Aleatorylamp

[aleatorylamp]

Hello Ivan, Hello Hubbabuba, Hello Papingo!

Following the confirmation that there was indeed such a thing as Boost-Burst ("Exhaust Dabbing") on the Sparrow, and after digesting the latest information, I decided to take the bull by the horns and apply what I learnt in these days from the exchanges on the thread.
Thus, I:
1) increased the max N2 output RPM, as that seemed a bit low both compared to the specifications and to the power needed in the simulator. This means that now 9500 RPM is at 84% Throttle at S.L., not 91% as before. Max. power (aka Boost-Burst) is now at an equivalent of N1=108, if there were an N1 spool on a single-spool turbojet...
2) left Idle Speed as before. RPM is correct at 3500 and power not too high to be a problem.
3) applied jet .air file airfoil parameters to wing angles.
4) reduced Drag at the base of the Mach Wall in Table #430, and lengthened the slope running up towards it in the two previous columns (so the 2nd column before the slope was above zero too). I was trying to get lower Drag at higher speeds, and higher Drag at lower speeds.
5) Regulated Zero lift Drag and Induced Drag (Oswald) to get S.L. non-boost and Boost speeds correct, and then went up to 20000 ft, found it was a bit too fast, reduced the base of the Mach wall in table #430 by 1, got quite good results, and then went back down to S.L. to see what had happened there.

So, for the moment the results look very promising:

S.L:
_84% power: 9500 RPM, 1767 flb thrust, 494.8 mph (over by 3.8 mph)
100% power: 10600 RPM, 2190 flb thrust, 548.0 mph (under by 5 mph)

19680 ft:
100% power: 10800 RPM, 2180 flb thrust, 562.6 mph (almost exact, over by only 0.6 mph)

Non-boost speeds at altitude are rather ambiguous. Turbine power at 9500 RPM is insufficient here and has to be compensated with greater RPM. Possibly invading the red zone at altitude is OK.

_90% power: 10250 RPM, 1122 flb thrust, 522.0 mph (The correct non-boost speed)
_77% power: _9500 RPM, _950 flb thrust, 482.0 mph (speed too low with correct RPM setting)

Thanks again for your your input and cooperative efforts!
Cheers,
Aleatorylamp

[aleatorylamp]

Hello again!

Well, let´s see if this .air file is any better now... at least I have the feeling it is.
It is done so that at 80% throttle, the engine generally stays at maximum-continuous power, 9500 RPM, and boost-burst would be at 100% throttle with 10600-10800 RPM or higher, depending on altitude.

I also hope to have been able to improve yaw, roll and sideslip behaviour, but would need some feedback here, as I´m not really very good at flying.

Here´s a screenshot for eye-candy and the new .air file.
Maybe we´re slowly getting there!

Cheers, and thanks again for all your support.
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

Just downloaded your new Volksjaeger AIR file. I will check it out later tonight if I get a chance.
The speeds at various altitudes seem pretty much correct at this point. I suspect it won't get any better.
What do you see are the issues you still want to address? I will do a general check and also look for the specifics that you list.
From Hubbabubba's comments, I already know the ground handling is very poor.

I have also been experimenting with a Me 163B that I downloaded.
It is a FS98 version and does not have any guns of course.
The aeroplane seems to have some serious handling issues and controls have very poor harmony.
The biggest problem that I ran into with the Me 163B was that its trim was so far off as to make it un-flyable because it would constantly loop as speed increased.
This seems to be a pretty common problem with FS98 aeroplanes I have imported so perhaps that is one of the serious differences between simulators.
The main reason for the download was to figure out how sounds work with a rocket plane. I will be looking through the configuration files to see if I can figure things out.

In doing a bit more research on the HL-10, it appears that its main limitation was the fact that it had such a short time for its engine run.
Its engine only had enough fuel for 100 seconds of full power but in that 100 seconds, it could go from about 40,000 feet up past 90,000 feet OR
go from 450 MPH to almost 1300 MPH. One has to wonder what its true limits were if it had a longer engine run. My version will not be realistic in that it will have enough fuel for at least 30 minutes of powered flight. It will also carry an armament, probably 2 x 20mm cannon.
Another unusual thing is that it was always landed as a glider and that landing was done at VERY high speed and at a ver high angle of attack.

- Ivan.

[Ivan]

Check your email.....

[aleatorylamp]

Hello Ivan,
I just lost a post because it timed out and wouldn´t allow re-logging-in. It had taken me an hour to prepare, and I´ve forgotten what it was all about! Anyway, let´s see if I can remember, before this one times out too!

Well, I opened my mail, thanks a lot, and adjusted Idle RPM to 3000, down from 3500, and it didn´t affect restly performance. Now the plane slows down better!

Then, I tried to reduce the max. Boost-Burst thrust to the newly specified 2028 flb, but I had to leave it the way it is. FS needs 160 more flb thrust to maintain high-performance power. This is presumably because "Exhaust Dabbing" gives more thrust with less RPM increase, more like afterburning, and FS only allows simply pushing the throttle to 100%, which is obviously different.

Your HL-10 sounds intriguing! It is a wing-less airfoil-shaped fuselage, or a fuselage-less short wing? Your idea for a practical application in CFS sounds fine! ...and the fact that it is a rocket-plane is an added plus!

Although everybody seems totally against using Rocket .air files, for their exaggerated their simplicity, it is however precisely this that I find very appealing! - AND they maintain their FULL power ALL the way into the Stratosphere!

I was still experimenting with the V1´s rocket .air file, but I think I´ll move over to the Me-163 - a true rocket. The V1, being a Pulse-Jet, would in reality need a Jet-Engine .air file. I was also trying to get the sound working. Hubbabubba had poointed out there was one in the CFS1 Sounds folder. I also still have to see how the Me262 and Me163 behave in FS98. I have a few stabilized versions of the Me163 .air file to do some more in-depth tests, as the original .air file is useless! You found that too!

Anyway, time for a belated lunch now!
Cheers,
Aleatorylamp

[aleatorylamp]

Hello Ivan,

I thought you might like stabilized FD for the Me-163 Rocket. It was originally by a Captain Slug, and was stabilized many years ago by a friend called Christoph Ruhtenberg, who liked making all sorts of FS98 aircraft more flyable by providing his "EYA" (Enjoy Your Aircraft") FD for them.

My humble contribution to this cause is the addition of a Rocket .air file, and also involves adjusting the max. flb thrust parameter so that with the correct Zero Lift and Induced Drag, max. 596 mph speed and 3800 flb thrust are as correct as possible, as per Me163 S.L. specifications. This was possible thanks to the Beckwith Gauge Stack, which Christoph Ruhtenberg wasn´t using when he stabilized these FD.

Hopefully the FD work well for you. With Autopilot engaged for testing, there may be some slight trembling near top speed, but it disappears when switched off.

Also, I increased the tankage from 45 USG to 90, subtracting the difference from the Dry Weight, but it may be more useful to further increase it. The 60 rpg 30mm ammunition is still in the Dry weight, as I haven´t made a Dp file.

Anyway, here´s the FD in Rocket and Jet versions, for the event you may find them of use - and a screenshot just for fun. (I made the model red!)

I think it actually flies quite well!
Cheers, and enjoy!
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

Thanks for the AIR file for the Floh. (Nur ein Floh....)
I will check it out when I get a chance. I expect to be pretty busy today. Tomorrow is the first day of school for my kids and my Son's computer still is not operational. It seems to have a corrupted Windows 7 Operating System and does not start. I can reinstall, but need to get some data off it before overwriting it. I also need to find installation media for the MS Office that was installed there. The Anti-virus is no issue because it was provided by our ISP.

Regarding the Heinkel 162:
I did a bit of a check on it and perhaps I have some information that may be helpful.

1. Check your Moments Of Inertia values in Record 1001. Your Yaw / Directional value is much too high.
If you need, I can try to run some calculations for you to give a better estimate, but when I dropped it from 120K down to 12K, it seemed to work better. I believe this is the main cause of the lack of steering when taxiing.

2. Increase your Braking strength in Record 1101. It seems to be also way too low which again would affect steering during taxiing.

3. You might have to adjust Gear contact points and spring factors as a result of the increased braking so the aircraft does not rock so much.
I believe the track is too narrow. By looking at your model in DPED, it appears that you can get by with main wheels that are 38 - 40 inches off the centerline (instead of the current 30 inches) and that also would help ground handling.

4. In looking at the DP file, I believe your Scrape Points are also pretty far off. As long as you are changing their location you also might want to increase their strength to around 720K or so. You can increase more if you like. This would make it a bit sturdier so that a scrape on the tail skid would be less likely to explode the aircraft.

Handling in the Air.....

5. Your Dihedral effect and Lateral Stability appear to be way too high. The pilot report states that this aeroplane was neutrally stable though we often adjust it slightly to make it more AI controllable.

6. The Roll moment due to the Rudders is also way too high. The aircraft can be rolled almost as fast with the Rudder as it can with the Ailerons. Because of the Dihedral one would also expect the Roll moment to be in the opposite direction though I don't have any sources that make any comment about this.

7. Here are a couple other issues that don't really affect flight handling or even ground handling but you might still want to consider:
The Stall Warning angle is currently set a bit odd at about 40 degrees which seems a bit high.
The Table 430 Mach Drag value at Mach 1.0 seems a bit high. I have a tendency to set these values high for Propeller Planes because of their shape, but this aeroplane is much better streamlined. It also might affect your maximum speed at altitude and perhaps that is why you have it so high.

Hope this helps.
- Ivan.