Author Topic: Maybe the 190s arent wrong....or how to be really unpopular in 1 step (Read 12866 times)

gripen · « **Reply #345 on:** February 10, 2006, 02:23:41 AM »

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Originally posted by Crumpp
Cause we are talking about your claim on the corrections. Your whole argument has been based off assumptions from this test.

Now you try to change the subject, we are talking about the V34 and the V5g with BMW 801J. The calculated chart showing compressibility correction backwards has nothing to with this discussion.

My argument is based on flight tested data of the V34. I have posted above the results and even part of the flight log showing the corrections.

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Originally posted by Crumpp

Yeah according to you According to Focke Wulf it had a different motor and was an export version.

The claimed output match the BMW data sheet as well as the A-5/A-6 manual. From Bookie's site:

"Turkey - Focke-Wulf 190 Aa-3
In the middle of 1942 the RLM issued an export order for FW 190s to be sent to Turkey. Turkey received 72 FW 190 Aa-3 (a for auslandisch - foreign) aircraft between October 1942 and March 1943. The first FW 190 Aa-3 was built in August 1942. The FW 190 Aa-3 received its own Werk Nummer block, 0134 101 - 0134 172 (although it is not known if W.Nr 110, 123, 146 and 148 were handed over). These aircraft were basically FW 190 A-3s, with BMW 801 D-2 engines, and FuG VIIa radios. However, they did not have FuG 25 radios, and had an armament fit of four MG 17s, with the option of installing two MG FF/M cannon in the outer wing position."

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Originally posted by Crumpp

Using the FW-190A5 Rechlin flight test results for a normal finish FW-190A5at an altitude of 6300M:

Again, that data is not corrected for compressibility and the BMW 801D2 did about 1440ps + exhaust thrust at 5600m. Using NACA estimation methods, that means roughly 12-14% output increase ie equivalent shaft power was somewhat over 1600ps. That means over 150ps shaft equivalent output over the V5g airframe with turbo charged BMW 801J because turbo uses the exhaust energy. In addition turbo required additional ducting as seen below in the case of the Ju 388.

There is no way the V5g with turbo charged BMW 801J would had a lower drag than a clean A-5 airframe due to additional ducting.

gripen

Crumpp · « **Reply #346 on:** February 10, 2006, 03:35:35 AM »

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There is no way the V5g with turbo charged BMW 801J would had a lower drag than a clean A-5 airframe due to additional ducting.

Hint: It did not have a turbocharger at that time. The BMW801 was itself a practically a prototype. The BMW801J0 became the basis for the J1 and J2.

Glad you found a website to back up your claims. Me, I will trust Focke Wulf documents.

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Again, that data is not corrected for compressibility and the BMW 801D2 did about 1440ps + exhaust thrust at 5600m.

Depends on the BMW801D2 and what timeperiod your talking about, Gripen.

All the best,

Crumpp

Charge · « **Reply #347 on:** February 10, 2006, 04:11:19 AM »

"There is no way the V5g with turbo charged BMW 801J would had a lower drag than a clean A-5 airframe due to additional ducting."

What kind of external ducting did it have?

Did it have the same type of intake as some tropicalized versions had or what?

Are there any pictures of V5g?

-C+

gripen · « **Reply #348 on:** February 10, 2006, 05:43:21 AM »

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Originally posted by Crumpp
Hint: It did not have a turbocharger at that time. The BMW801 was itself a practically a prototype. The BMW801J0 became the basis for the J1 and J2.

I tend to believe Von Gersdorff & Co on engine questions. We are talking about calculation of the V5g with the BMW 801J and the calculation needs just supposed specs of the engine.

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Originally posted by Crumpp

Glad you found a website to back up your claims. Me, I will trust Focke Wulf documents.

Well, you have used same site as a source. Besides, it's very common in the german documentation that the engine is described as the BMW 801D despite it actually was the D-2 (as an example A-5/A-6 manual).

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Originally posted by Charge

What kind of external ducting did it have?

The spec sheet does not give details but it needed atleast intake as well outlet for the intercooler (picture of the Ju 388 gives an idea). The turbo of the BMW 801J is claimed to be aircooled so also that would have needed some additional air.

gripen

Crumpp · « **Reply #349 on:** February 10, 2006, 09:21:04 AM »

I have plenty of pictures of FW-190V5g. I will post some.

All the best,

Crumpp

hitech · « **Reply #350 on:** February 10, 2006, 10:11:51 AM »

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FW-190V5g Cd (tot) = .0177
FW-190A5 Cd (tot) = .024

Can we say somthing dosn't pass a smell test?

You realy belive a 25% reduction in drag co on a like air frame with only small changes?

HiTech

Crumpp · « **Reply #351 on:** February 10, 2006, 11:40:36 AM »

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You realy belive a 25% reduction in drag co on a like air frame with only small changes?

Small changes?? If there where only small changes FW-190's would have been restricted to the airspace right above there own fields where they could glide to a landing after a few minutes of powered flight. FW-190V5g is a new type prototype.

In addtion to the exhaust reroute, Hitech, there were over 40 design changes to improve the cooling of the motor.

I would not call cutting new ducting, cooling fan, radiators, and rebaffling the motor small changes? Have you even noticed the external shape of the internal intakes blisters? They are different on the outside and very different on the inside.

Not to mention the addition of weapons with raised covers for all.

Hardly small changes. Notice the CD goes from very low for an aircooled motor to similar to most WWII radials?

Seems a rather major increase in cooling drag alone. While the actual drag reduction benefits were not realized the cowling was kept sufficiently tight to reducing the wet area. So even though the CD is normal, the aircraft remains realtively low drag.

Yes I find a 26.25% increase in the FW-190A CD(tot) believable with an understanding of the design changes.

All the best,

Crumpp

Angus · « **Reply #352 on:** February 10, 2006, 06:22:07 PM »

Only parasite drag I presume?

Crumpp · « **Reply #353 on:** February 13, 2006, 06:18:34 PM »

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FW-190A5 Cd (tot) = .024

It's .022 BTW not .024.

Angus · « **Reply #354 on:** February 14, 2006, 03:24:53 PM »

A reduction like that in parasite drag is stunning. If it was that reduction in total drag, it would be even more stunning. Are you really sure of this? This is easily the difference between 2 totally different airframes. Tells more than a hell lot of horsepowers.

Crumpp · « **Reply #355 on:** February 14, 2006, 09:26:15 PM »

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A reduction like that in parasite drag is stunning.

It's an increase not a reduction. Look at the FW-190 weapon installation. Blisters, wing covers, barrels, and all the changes to the motor compartment.

Have you even seen the FW-190V5 series? They were new type prototypes without weapons and the very first installation of the BMW801 series. The earlier prototypes had the BMW139.

Look at the P51 series. The P51D gains 11% more drag than the P51B. That is just adding two more weapons, engine changes, and a huge drag reducing canopy!

I find it extremely arrogant of some people who think they know more than the actual engineers who designed these aircraft. Especially using simple calculations that do not include the level of detail required for full analysis.

All the best,

Crumpp

justin_g · « **Reply #356 on:** February 15, 2006, 02:33:05 AM »

Bubble canopy increased drag on the P-51D. Also most B had the exact same engine - but the D was 5mph slower, I doubt -5mph = +11% drag.

Angus · « **Reply #357 on:** February 15, 2006, 06:13:47 AM »

So you're comparing the cleanest to the dirtiest?

Crumpp · « **Reply #358 on:** February 15, 2006, 07:57:48 AM »

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Bubble canopy increased drag on the P-51D. Also most B had the exact same engine - but the D was 5mph slower, I doubt -5mph = +11% drag.

Not according to Dean's AHT. The P51D recieved extra guns and had a different motor. The bubble canopy was a drag reducing measure. Do you have something showing that it increased drag?

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So you're comparing the cleanest to the dirtiest?

So your implying just the finish can effect it that much? You probably right, some planes did gain substantial benefits just improving the surface finish.

Maybe it is just cooling gill position that is causing a 10% drag variation. I wonder what the variation would be between having gills and not having them would be??

Lets look at some measured drag test's of the P51 series for variation. Keep in mind several of these are flight tested:

XP51:

Wow! We see a huge variation in some cases between the P51 variants.

I think it is a conspiracy between North American and the USAAF to hide the true performance of the aircraft. In reality the P51 must have performed much worse than published numbers. Just look at the huge variation in drag!

No way it could have anything to do with the level of detail of the calculations, flight tested aircraft set up, or solid science.

All the best,

Crumpp

MiloMorai · « **Reply #359 on:** February 15, 2006, 08:46:00 AM »

Not according to Dean's AHT. The P51D recieved extra guns and had a different motor. The bubble canopy was a drag reducing measure. Do you have something showing that it increased drag?

Initially, the P-51B and C had the Packard V-1560-3 engine. There were four hundred P-51B-1-NAs and 250 P-51C-1-NTs built. With the introduction of the P-51C-5-NT onto the Dallas production line and the P-51B-15-NA in the Inglewood production line, the Packard V-1560-7 engine was adopted as standard. Over 3000 P-51Bs and Cs were built.

The P-51D used the Packard V-1560-7.