Buchons, Spits, Bearcats, and a real Pilot

[Chingachgook]

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[Soren]

The 109G6 engine is more powerful (according to you), the propeller is more efficient and the frontal area smaller yet it is significantly slower than the Buchon.

I'm not talking about the G-6 Chinny, and btw the reason for the Buchon's speed lies with its engine and propeller performance at altitude.

The engine cowl may look turbulent, but don't let looks fool you.

And exactly what do you know about that Chinny ? And no, looks in this case are not decieving - as soon as there's a bulge in the way of the incoming air there's going to be turbulence, and turbulence equals drag.

Unless there is another variable that we are missing, the cd number on the Buchon has to be lower than the G6, and not by a small amount.

Quite the contrary, the Buchon has more power than the G-6, therefore if we assume the prop and drag of the airframe is the same the Buchon should be faster - however this is not so, the Buchon considerably more draggy than the Gustav, and the only reason its faster is because of its prop and engine performance.

FYI - the Chino Buchon in question had no guns at all.

It has guns, I've seen it.

 

[Chingachgook]

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[Soren]

The Buchon Ha-112MIL has 1,600 HP Chinny, against the G-6's 1,475 PS - thats the facts, it has nothing to do with how I want it. The G-10 has ca. 1,780 HP and is faster than the Buchon at alt and considerably faster at SL.

And btw, that up there is not the Buchon were using as a comparison, it has a different wing shape and no guns, which means its a mix between an earlier version with a three bladed prop and the four bladed and elliptical wing-tip version.

I'll admit I was wrong about the Chino example having no guns however, guess I've seen too many with guns and nearly none without.

 

[Chingachgook]

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[Chingachgook]

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[Chingachgook]

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[Soren]

You lost me from here "You know as well as I that G6 might have more real hp (?). " and onwards.

What exactly do you mean by "real hp " ??

The Merlin is rated at 1,600 HP, the DB-605 at 1,475 PS or ca. 1,450 HP. So everything else being equal the Buchon should be considerably faster, esp when you consider that the Merlin does better at alt. Yet the Buchon isn't that mch faster;

Bf-109 G-6: 403 mph
Ha-112MIL: 416 mph

Now take into account that the G-6 is the dirtiest wartime 109. The K-4 would do 450 + mph (720 + km/h) at 1,780 HP @ 1.8ata, thats a good 34 mph faster than the Buchon0.

 

[Chingachgook]

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[DerAdlerIstGelandet]

The actual Buchons used by the Spanish airforce had two 20 mm Hispano-Suiza 404/408 cannons. One in each wing.

 

[Soren]

The Buchon has 150 more hp than the G-6 Chinny, not 125 - Remember the 1,475 rating is in PS.

And my point with the K-4, which is not very different from the G-6/AS, G-10 G-14, was to show you just how much cleaner it is compared to the Buchon.

 

[Chingachgook]

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[Soren]

Comparing speed figures is sometimes very misleading Chinny, but the G-10 and G-14 both did 685 km/h at alt and 585 km/h at SL when in clean condition - which is faster than the Buchon, and much faster at SL.

 

[Chingachgook]

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[Chingachgook]

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[Soren]

The GL/C-E2 for a clean G-14 with ASM engine gives 348 mph at Sea Level and 422 mph at full throttle height.

DB 605 ASM is 1800 PS at SL (1,75 ata/2800 rpm).

So looks like Buchon is cleaner than G series.

The G-14 will do 569 km/h (355 mph) at SL with a 300L drop tank attached Chinny:
http://aycu28.webshots.com/image/9387/2004098314668028418_rs.jpg

Without the drop-tank its 585 km/h at SL and 685 km/h at full throttle height.

So no, the Buchon is not cleaner.

 

[Chingachgook]

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[Soren]

Only the DB-605 DC engine would produce 2,[email protected] - the ASM, AM etc etc engines used by the G-6/AS, G-14 and G-10 could run at a max boost pressure of 1.8ata = 1,800 PS. Now as alitude increases the power of the DB engine decreases faster than that of the Merlin (Hence why they are so close at alt), but try comparing SL speeds - the G-6/AS, G-10 and G-14 are alot faster on the deck ! The Buchon does about 540-550 km/h at SL, where's the G-10 and G-14 both do 585 km/h at SL.

The GM-1 system wasn't used by the G-14, G-10 or K-4.

 

[Chingachgook]

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[Hop]

Now as alitude increases the power of the DB engine decreases faster than that of the Merlin

That's generally true of 2 speed Merlins, but I believe the Buchon used an old single speed single stage Merlin, basically a slightly updated version of the engine in the Spitfire V.

The Buchon does about 540-550 km/h at SL, where's the G-10 and G-14 both do 585 km/h at SL

The problem with single speed superchargers (if that's what the Buchon had) is that they are optomised for a single altitude. If the engine develops maximum power at say 15,000ft, then the supercharger at that altitude is spinning at just the right speed to compress the air to the maximum useable by the engine.

However, at sea level the supercharger is still spinning at the same speed, and wasting a lot of power because of it.

So, to compare power and sped you really need to know the power developed at the particular altitude, and the speed achieved. If one plane has 1500 hp at 10,000ft and does 400 mph, it's likely a lot less draggy than one that has 1500 hp at 20,000ft and does 420 mph.

AFAIK, at sea level a G10 does 585 km/h with something over 1800 hp. I'd be suprised if the Buchon had even 1500 hp at sea level.