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Old 06-06-2012, 02:42 PM
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Crumpp Crumpp is offline
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Quote:
To maintain given angle of bank at given KEAS, power must increase with altitude.
I know this very well MIG3.

If you look at the thread before my altitude conversion there is only one document from this report posted.

Page 16 is when IvanK posted one snippet from the report:
http://forum.1cpublishing.eu/showthr...=32285&page=16
Page 17 is when I showed Kurfurst how to convert performance to altitude from that snippet:
http://forum.1cpublishing.eu/showthr...=32285&page=17

Here it is the only information in the thread at the time I replied:



There is not enough information to do any kind of detailed analysis.

None the less, I knew Holtzauge would be up to his old tricks again as soon as he posted. So I included the answer to specific performance in my very next reply.

Quote:
Crumpp says:

The specific numbers for rate and radius will change in proportion to density ratio which is a universal application.
http://forum.1cpublishing.eu/showpos...&postcount=170

But Mr Holtzauge ie Msc Aeroengineering blah blah blah did not understand.

There is no power information provided and the report is obviously discussing theory and not reality with the different degrees of flap. So when I answered Kurfurst question about how to change altitudes, there was nothing to convert in terms of power to get specific performance.

Holtzauge is not some engineer. He is an internet troll plain and simple.

Why do I know this?

I rather long history of dealing with him. Let's look at how to vary thrust production with altitude. This is from the old Ubizoo board. The discussion comes about because some folks cannot seem to line up power in terms of Equivalent Airspeed. They kept coming up with a load factor that was way too high when they used EAS. Why? They knew how to parrot some TAS formulation but did not understand the theory behind it. Therefore when they went to convert EAS back to TAS, they did not convert their power and ended up with much higher load factors.

A basic aircraft performance text, Perkins and Hage, "Aircraft Performance, Stability, and Control:


Quote:
Crumpp says:

Lastly, for all the "experts"...

If we want to hold our assumptions the same then we need to vary thrust with density.

2300 hp * .85 = 1955thp

1955thp*325 / 180KEAS = 3529.861111lbs of drag

sigma = .53281 @ 20,000ft

SQRT(.53281)* 3529.861111lbs of drag = 2576.58lbs of drag


2300 hp * .85 = 1955thp

1955thp*325 / 246.6KTAS = 2576.5lbs of drag
http://forums.ubi.com/showthread.php...=1#post2939042

Holtzauge says:

Quote:
Just had a closer look at your calculation and it does seem you are in dire need of an “expert” to “demonstrate” aerodynamics to you :

You get confused by your own equations.

By definition, EAS means that you have the same dynamic pressure q at both altitudes. You don’t seem to have grasped this since you suddenly show 2576.5 lbs drag at 20000 ft and 3529.86111 lb at SL.

You see the drag will be the same at both altitudes, i.e 3529.86111 lb. Otherwise it’s not EAS.

So entering the correct drag into the thrust equation yields:

Ps hp * .85 = Pt thp

Pt thp*325 / 246.6KTAS = 3529.861111lbs of drag

So Pt=2678.35

Which gives Ps=2678.35/0.85=3151 hp

I guess you shot a really big hole in that foot now Polly. All the while you have been parroting on how important it is to use EAS and you can’t seem to be able to use it properly yourself…
http://forums.ubi.com/showthread.php...=1#post3177597

That is why I ignore the guy.

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