Couple of quick numbers.

[fscott]

Bloom25, very nice statistics, I'm sure I don't that much time to do all those tests.  

Ok folks, bloom25 has some very good numbers here, and it's obvious that a few planes could be off, way off.  Does this strike any of you as unusual?  We all demand accuracy in flight models. I assume we are all ok with these numbers? IF we aren't, then we need to let HT know about it.

Funked, I like pollocks so I will answer you.    I am not sure how you got 24 seconds. Ther dang thing will ride at 140mph for 15 seconds almost that long!  Bloom25 also got some rather large numbers for the N1K2. I think you may want to be sure you are holding the plane level.  I did not use trim of any kind. All trim was centered prior to flight.

he enxt thing I'm gonna do is compare the same tests against Warbirds flight modelling. Let's face it, most of us were probably Warbirders and some of us actually swore by those flight models.  I'll try to get around to it son. If not, Bloom25 could you do some in WB also? Smae setup, same attributes.


fscott

[fscott]

Please don't ride me about my typing. Yes I can spell, I just type too fast and use two fingers.  No I did not call you "son", that was meant to be "soon."

fscott

[-aper-]

bloom

some hints for your test:

1)
When you cut engine in La-5 (or N1K)her propeller stops, and  when you cut engine in Yak(or P-51) her propeller continue rotation.

2)
It's better to test decreasing of speed in 250-150 mhp range because at 100 mph planes getting stall and autotrim can not keep them in level flight.

[funked]

Flakbait yes Wells could whip something up.  

Fscott, I'm not Polish, and as my own tests give much different results, I must continue to question the validity of the numbers on this thread.

Here is the procedure I used to match your numbers (Fscott):
Load aircraft to 100% fuel, full ammo, no external stores.
Take off, climb and maintain 1,000 feet.
Establish airspeed at 200 mph TAS.
Turn off the engine.
Hold plane 1000 feet by applying increasing back pressure with stick.
Record time from engine cut-off until 100 mph TAS is reached.

To match Bloom's numbers I did the same test but with 25% fuel, and 7,000 feet altitude.

I've done a fair amount of virtual test flying but I can't match the numbers either of you are getting.  This means either one of us is varying from the stated procedure, or (God forbid) our FE software is giving different results.

I'm going to do the test again and post a film.  I advise you guys to do the same.  Any other pilots who are bored might wish to do it also.  Let's see if we can find out if it is procedure or software.

[bloom25]

I used auto level as soon as I reached 7000ft, then let it stabilize at that altitude and 200 mph.  Now cut engine and see how long it takes to get to 100 mph.  (Or in the case of a few planes when they spin.)



------------------
bloom25
THUNDERBIRDS

[funked]

OK Bloom can you do it again without autolevel?  The planes behave very different under autolevel - some of them hold altitude while others don't.  As you know, the ones that drop altitude will deccelerate slower due to the potential energy of gravity.

[This message has been edited by funked (edited 10-22-2000).]

[funked]

OK I was finally able to get close to Fscott's N1K2-J number.  It was my fault, I was doing the procedure wrong.  

Instead of setting throttle to hold 200 TAS I was idling the throttle at 250 then cutting the engine as speed dropped to 200.

My time went from 24 to 45 seconds when I made that change.

With the throttle at idle, the blades will go to fine pitch in order to maintain RPM.  Then when you cut the engine the blades stay there.

If you hold throttle to maintain 200 mph, the blades will go to an intermediate (coarse) pitch setting, then stay there when the engine is switched off.

Fine pitch creates more drag than coarse pitch, which explains the difference in coast times from 200 to 100 mph.

Since every plane is going to have different prop drag characteristics and a different pitch setting to hold 200 mph, you will get different amounts of drag from the prop on different planes.

It looks like the HTC guys are right, we are mostly measuring prop drag with this test.

[-lynx-]

 

It looks like the HTC guys are right, we are mostly measuring prop drag with this test.

Which basically says - "...can we have a prop pitch indicator in our cockpits please as well as manual pitch control where it was available..."

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lynx
13 Sqn RAF

[flakbait]

I posted this in another thread [Interesting test results] in regards to the N1K2. I was able to pull a roughly 180 degree turn, in blackout, with only 50mph speed loss. I put the field off to one side as a marker, waited for 300mph, then hauled it around. When I checked the speed, after the lights came back on, I had only lost 50mph.
N1K2 film

This is either beyond strange, and a one shot occurance, or a SNAFU.

------------------
Flakbait
Delta 6's Flight School
"My art is the wings of an aircraft through the skies, my music the deep hum of a prop as it slices the air, my thrill the thunder of guns tearing asunder an enemy plane."
Flakbait
19 September 2000

[This message has been edited by flakbait (edited 10-23-2000).]

[funked]

Flakbait:

Film link is broken for me.

I was able to duplicate the result though.

What makes you think a real N1K2 could not do that?

(That's a real question not a smart bellybutton remark.)


[This message has been edited by funked (edited 10-23-2000).]

[flakbait]

Fixed the link.

It's a feeling I get when I can pull stunts like that, Funked. An aircraft that can pull 6+ Gs for 180 degrees yet only lose 50mph of speed. To me that's strange. Weight is obviously a large factor in speed retention, yet the N1K2 weighs 3/4 of a ton less than a P-51 [8,818lbs vs. 10,600lbs]. Power loading now comes into play, I think. I won't even try to figure everything, since I know I'll get it wrong. What I've got so far is this. The N1K2 has 4.43lbs/hp, and a Fw-190A3 has 4.90lbs/hp. Which means the A3 should do the same thing the N1K2 is capable of, right? I use the A3 as an example, since the web site I raided didn't list a weight for the A5.

I'll stop there, since I don't want to screw up and bring a firestorm down. If the N1K2 is fine, and either Pyro or HiTech say it is, I'll shut my trap and be done with it. No sense fixing what isn't broken. But I think it is broken, in order for performance of that magnitude to be common place something is up. It could be HTC picked the wrong plane to put it, or that a typo snuck in the code. I honestly don't know.

My gut says something is wrong here, and I am well aware Pyro and HiTech outrank my gut. What it could be I don't know, but performance like that is not normal for most aircraft. It might be that none of the aircraft mush when you pull up hard. Or it could be drag of some sort is too low. I feel drag with power off isn't enough, but that's another thread.


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Flakbait
Delta 6's Flight School
"My art is the wings of an aircraft through the skies, my music the deep hum of a prop as it slices the air, my thrill the thunder of guns tearing asunder an enemy plane."
Flakbait
19 September 2000

[This message has been edited by flakbait (edited 10-23-2000).]

[funked]

Flak did you read Wells' thread on E-retention?

[flakbait]

Sorta skimmed it, but I haven't really gone through it yet. Why do you ask?

[edit] just tried reading the thread, but it was deleted.


------------------
Flakbait
Delta 6's Flight School
"My art is the wings of an aircraft through the skies, my music the deep hum of a prop as it slices the air, my thrill the thunder of guns tearing asunder an enemy plane."
Flakbait
19 September 2000

[This message has been edited by flakbait (edited 10-23-2000).]