Author Topic: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.  (Read 11801 times)

Offline Krusty

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #15 on: November 10, 2010, 11:25:08 PM »
German engines and RAF engines have never really been all that par with each other. German designs were really meant to minimize the amount of precious metals they consumed, as Germany had little access to replace it. They squeazed more horsepower out of less space, often sacrificing aerodynamic consideration. The RAF could afford to tackle a resource-rich design and make it larger, then smooth that over with aerodynamic panels. Comparing them at similar power may yield similar results, or you may be nowhere close. Too many variables to just list horsepower.

An interesting question would be, how much THRUST did they have? 410s had larger prop blades, I believe. Yet, they are still slower. It must really be clawing it's way throug the air compared to the Mossie.


Like I said, I think the drag is really the answer. Compare a P-38 to a 110G, and I think you get the same comparison as a Mossie to a 410. One sleek, smooth, curved, rounded, the other just sheer brutality.


It has an elegance, don't get me wrong. But "slick" it ain't.

Offline Plazus

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #16 on: November 10, 2010, 11:37:15 PM »
With the recent talk about the Me410, here's something I've been wondering...

So here is the thing I can't quite get my head around. Mosquito is whopping ~40mph faster on the deck using roughly ~370hp less power and having ~6sqm more wing area. :confused: I'm sure that the Mosquito has clearly smaller drag coefficient but....40mph??? Other explanations? Considerable larger induced drag due to quite high wingloading (at these speeds...doesn't seem likely)? Significantly poorer prop efficiency (I doubt that)? It must be something that I'm missing since after all, the data is there and it is from flight testing (/calculation in Me410's case?).

Comments, suggestions, discussion?

Well there is one missing piece of information that Krusty and Karnak has both failed to explain. After doing some rough calculations on paper and pencil, I made some pretty logical conclusions. Given that the Mossie can achieve ~40mph faster with less power in comparison to the Me410 and Bf110, one would think something would be amiss. But, my friend, I promise you, it isn't what it seems. My fast calculations show that the Mosquito has a 59% greater sex appeal than the two German planes. It's true! The Mosquito is simply that sexy! It just doesn't need all that excess horsepower for that top speed.

Here are my my calculations to prove it:

Quote
Bf110 - Is it sexy? No.
Me410 - Is it sexy? Not quite.
Mosquito Mk.6 - Is it sexy? Friggin yeah!

So in conclusion:

Sex appeal > raw horsepower






 :D
Plazus
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Offline Scherf

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #17 on: November 10, 2010, 11:50:38 PM »
^ lol

Anyhoo, I've had a quick squizz at a docco I have re: the balance between thrust and drag for the Mossie prototype - it talks about back pressure, power abosrbed by airscrew, airscrew efficiency, ejector exhaust power, radidator heat regeneration, basic drag, induced drag, carburetor air collection and cooling drag.

So I suppose any of those could be out of balance in comparing the two aircraft.
... missions were to be met by the commitment of alerted swarms of fighters, composed of Me 109's and Fw 190's, that were strategically based to protect industrial installations. The inferior capabilities of these fighters against the Mosquitoes made this a hopeless and uneconomical effort. 1.JD KTB

Offline Wmaker

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #18 on: November 10, 2010, 11:56:52 PM »
Was the 315mph at maximum power, WEP?

Just like I stated in my original post, yes.


I would have expected the Me410 to do more like 330-335mph on the deck based on the British combat report I had read against it.  A Spitfire Mk IX (most likely an LF.Mk IX) in Italy chased one down in a long tail chase on the deck.

I would expect the cap between the Mosquito and Me410 to be smaller. That's why I started this thread. I'll calculate some Cd estimates later but right now it looks like that the Me410 would have to have almost twice the Cd that Mosquito has... :eek: Like I said, very hard to get my head around that fact. For comparison, Brewster has a Cd bit under ~0,03 and 109G ~0,024. Other is an inline engined fighter and the other has a large diameter radial...


unless the German engines are blowing a lot of that power on something else, such as driving superchargers that are doing nothing at sea level.

Well, superchargers are obviously accounted for but things like hydraulic pumps and electric generators do eat power but the differences in these should be neglible.
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Offline Scherf

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #19 on: November 11, 2010, 12:00:14 AM »
Might (might, ah say *might!*) help if you show us the aircraft speed equation you referred to, as well.

The other possiblity is that the Me 410's actual sea-level top speed at Notleistung was measured higher than you've calculated, but I've never seen any such measurement.
... missions were to be met by the commitment of alerted swarms of fighters, composed of Me 109's and Fw 190's, that were strategically based to protect industrial installations. The inferior capabilities of these fighters against the Mosquitoes made this a hopeless and uneconomical effort. 1.JD KTB

Offline Wmaker

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #20 on: November 11, 2010, 12:03:50 AM »
An interesting question would be, how much THRUST did they have? 410s had larger prop blades, I believe. Yet, they are still slower. It must really be clawing it's way throug the air compared to the Mossie.

It's a matter of prop efficiency. I have a couple prop eff curves for the VDM prop of the 109G (DB605A-1). But the differences on this front can't really be big enough to have a huge effect. Well, obviously seeing Mosquito prop eff curves would help...
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Offline RTHolmes

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #21 on: November 11, 2010, 03:55:56 AM »
P = ½ρv3ACd

P ∝ v3ACd

410 and mossie both ~1550hp, so:

3043(ACd)410 = 3563(ACd)mossie

(ACd)410 = 1.60(ACd)mossie

thats saying that the 410 has 60% more drag than the mossie at those speeds. the mossie was an exceptionally clean design so its feasible.

the calc also assumes that both aircraft are equally efficient at turning hp at the flywheel into thrust, a big assumption. ejector stacks and radiator output design can both add thrust, aero design for the nacelles, cowling and wing can reduces losses. if the mossie scores better on these (I suspect it does), it reduces the 60% difference in ACd.
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Offline Scherf

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #22 on: November 11, 2010, 04:57:42 AM »
Thanks for that, but are you using a speed of 356 at sea level for the Mossie? Surely that's the WEP speed, vs the 304 for the Messer, which is at Mil speed?

Or, are you using that HP as Mil for the 410 and WEP for the Mossie?

P = ½ρv3ACd

P ∝ v3ACd

410 and mossie both ~1550hp, so:

3043(ACd)410 = 3563(ACd)mossie

(ACd)410 = 1.60(ACd)mossie

thats saying that the 410 has 60% more drag than the mossie at those speeds. the mossie was an exceptionally clean design so its feasible.

the calc also assumes that both aircraft are equally efficient at turning hp at the flywheel into thrust, a big assumption. ejector stacks and radiator output design can both add thrust, aero design for the nacelles, cowling and wing can reduces losses. if the mossie scores better on these (I suspect it does), it reduces the 60% difference in ACd.
... missions were to be met by the commitment of alerted swarms of fighters, composed of Me 109's and Fw 190's, that were strategically based to protect industrial installations. The inferior capabilities of these fighters against the Mosquitoes made this a hopeless and uneconomical effort. 1.JD KTB

Offline RTHolmes

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #23 on: November 11, 2010, 05:20:39 AM »
from the OP charts, at sea level:

Me410: 2x 1558hp (Mil), 304mph
Mossie: 2x 1540hp (WEP), 356mph

:)
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Offline Scherf

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #24 on: November 11, 2010, 05:31:52 AM »
Cheers.
... missions were to be met by the commitment of alerted swarms of fighters, composed of Me 109's and Fw 190's, that were strategically based to protect industrial installations. The inferior capabilities of these fighters against the Mosquitoes made this a hopeless and uneconomical effort. 1.JD KTB

Offline Wmaker

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #25 on: November 11, 2010, 05:45:56 PM »
thats saying that the 410 has 60% more drag than the mossie at those speeds. the mossie was an exceptionally clean design so its feasible.

Well this is where we somewhat disagree. I don't quite see the 60% difference plausible. But since we are still more or less guessing here it doesn't really matter. :)

The prop eff difference could make a difference and yes the airframe geometry behind the prop is rather important. But I'd say both of them had rather neatly cowled inline engines. I'm sure the underwing radiators of the Me410 reduce reduce the air velocity for the prop below the wing somewhat. Well, it would need some serious CFD stuff to unravel these things in detail.

Anyways, I did some quick calcs using 2x~170lbs as exhaust thrust for the DB603As (values are based on the exhaust thrust chart for the DB605). I came up with 0,036 Cd for the Me410 at 315mph on the deck. That's not a zero lift Cd but includes both induced and parasitic drag. Anyway, 0,036 sounds pretty brutal.


Anyhoo, I've had a quick squizz at a docco I have re: the balance between thrust and drag for the Mossie prototype - it talks about back pressure, power abosrbed by airscrew, airscrew efficiency, ejector exhaust power, radidator heat regeneration, basic drag, induced drag, carburetor air collection and cooling drag.

That doc sounds really interesting and would probably help to make some basic calcs for the Mossie more accurate. Would you be kind enough to share if I PM'ed you my e-mail addy?
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Offline RTHolmes

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #26 on: November 11, 2010, 07:14:46 PM »
Well this is where we somewhat disagree. I don't quite see the 60% difference plausible.

I used your numbers so, assuming they are right, the 60% difference exists. the interesting question is why. :)
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Offline Wmaker

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #27 on: November 11, 2010, 07:20:40 PM »
I used your numbers so, assuming they are right, the 60% difference exists. the interesting question is why. :)

Yes, exactly.

I'm just saying that the difference can't be all drag. Just for comparison Cd0 of the Sopwith Camel is listed as 0,0378 not a big difference when compared to the 0,036 value for the Me410 that I got. Yikes!
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Offline Scherf

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #28 on: November 11, 2010, 08:51:51 PM »

That doc sounds really interesting and would probably help to make some basic calcs for the Mossie more accurate. Would you be kind enough to share if I PM'ed you my e-mail addy?

No worries, go ahead and PM me.

As per the above, I reckon there's more happening than just drag. What does that note top-right of the DB603A power curve chart say? I get it includes both static and dynamic (pressure?), but what's the rest? Does not take account of - is Rueckstoss engine back-pressure or exhaust thrust? If it's the former, it might begin to explain things.

On the face of it, it's very strange, 2x44 litres vs 2x27 litres. What's the "standard cruising power" from that graph? FWIW, the Mossie VI cruised at 240 mph or so with flame dampers, more without, think at +7 lbs/in2 but don't quote me.
... missions were to be met by the commitment of alerted swarms of fighters, composed of Me 109's and Fw 190's, that were strategically based to protect industrial installations. The inferior capabilities of these fighters against the Mosquitoes made this a hopeless and uneconomical effort. 1.JD KTB

Offline gripen

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Re: Me110G-2, Me410 and Mosquito Mk.VI maximum speeds.
« Reply #29 on: November 12, 2010, 11:11:56 AM »
Yes, exactly.

I'm just saying that the difference can't be all drag. Just for comparison Cd0 of the Sopwith Camel is listed as 0,0378 not a big difference when compared to the 0,036 value for the Me410 that I got. Yikes!

Well, the discussion would be more sensible by using the drag area (flat plate area) for the comparison. The Camel has a lot of wing area for a small and light plane so the Cd might look small. For a good reference in finnish I suggest Raunio's article serie in SILH couple years ago.