Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: agent 009 on September 23, 2005, 08:24:06 PM
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I posted this while back, but site has since dissapeared. Anyone got a source? Spit with DB 605 motor & ME 110 nose?
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°I'll try to find it.
If I remember it right, it outperformed the 109 with the same engine, at least in climb.
Which is rather to be expected.
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http://www.unrealaircraft.com/hybrid/spitfire.php
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Hehe, right on.
This is interesting:
"
After a couple of weeks, and with a new yellow-painted nose, the Spitfire returne to Echterdingen. Ellenreider was the first to try the aircraft. He was stunned that the aircraft had much better visibility and handling on the ground than the Bf.109. It took off before he realised it and had an impressive climb rate, around 70 ft. (21 m.) per second. Much of the Spitfire's better handling could be attributed to its lower wing loading.
The Spitfire's wing area was about 54 sq. ft. (5m²) greater than that of the Bf.109. The Messerschmitt was faster at low altitude, but at 11,000 ft. (3350 m) the speeds evened out. The DB 605A engine gave better performance, according to the test group, than the Merlin, which was rated 150 hp below the German engine. It gave the Spitfire a ceiling of 41,666 ft. (12700 m.), about 3,280 ft. (1000 m.) more than a Bf.109G with the same engine and 5,166 ft. (1475 m.) more than that of a Spitfire Mk.V.
After a brief period at Rechlin confirming the performance data, the modified Spitfire returned to Echterdingen to serve officially as a test bed. It was popular with the pilots in and out of working hours. Its career ended on 14th August, 1944, when a formation of US bombers attacked Echterdingen, wrecking two Ju.52s, three Bf.109Gs, a Bf.109H V1, an FW.190 V16, an Me.410 and the Spitfire. The remains of the hybrid Spitfire were scrapped at the Klemm factory at Böblingen."
BTW, 21 m/s is 4130 feet/min.
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Hi,
the good performence is caused by missing weapons!
The DB605A SpitVb only had 2730kg, this explain the very good climbratio and high alt performence, its more a Spit1b with 1310-1400HP.
Nevertheless the 109G was faster in all altitudes up to 10700m(35000ft) alt.
Greetings, Knegel
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Well it had been crashed landed. Kurfurst always complains that the British tested damaged 109s. What did the Germans know about rigging a Spitfire?
EN830 was produced in Apr 1942.
Interesting comment: Ellenreider was the first to try the aircraft. He was stunned that the aircraft had much better visibility and handling on the ground than the Bf.109.
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The armament does not account for a lot of weight, and they had a ballast instead of the radio.
The 109 was faster on the deck, - normal, for it's smaller in span, - while the Spitfire wins up high, - to be expected because of lower A.o.A. at lower speeds, - that is IAS.
I have some well graphed data on a 109G, - I'll go compare :)
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The aircraft was 300kg heavier with its guns fitted, and with the Merlin engine. A reduction in weight of 300kg(about 10%) would cause a noticeable difference in performance, especially climb.
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OK, so did the DB 605 powered Spit perform better than a Merlin powered Spit?
& which Spit is the contempoary one to compare to? 5 or 9?
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The Db spit did inded perform better than the original - with more power under the hood that was to be expected.
The teaser is that it also easily performed as good and better than a 109 with the same engine.
I am loing through my HD to find a good comparison - will post later
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Spitschmitt must've been a great ride, excellent frame with an even better engine!
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The teaser is that it also easily performed as good and better than a 109 with the same engine.
As was pointed before, that Spit was 300kg lighter than a usual Spit V.... and wasn't any faster than the 109 with same engine, in fact was slower at most altitudes:
(http://www.jagdgeschwader52.com/meyer/SpitVmitDB605Aspeed.jpg)
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Nice doc.
Funny, it does not match with the text though.
"
The Spitfire's wing area was about 54 sq. ft. (5m²) greater than that of the Bf.109. The Messerschmitt was faster at low altitude, but at 11,000 ft. (3350 m) the speeds evened out"
And you can not see the ceiling either.
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Originally posted by Meyer
As was pointed before, that Spit was 300kg lighter than a usual Spit V.... and wasn't any faster than the 109 with same engine, in fact was slower at most altitudes:
http://www.jagdgeschwader52.com/meyer/SpitVmitDB605Aspeed.jpg
Yep, and thats despite the difference of being a lightly loaded Spit missing 300 kg at least - I dont think this would change much at low altitudes, but at above FTH, being more lightly loaded definietely makes the aircraft quite a bit faster.
I wonder about the "109G" though. From the weight it seems like a 109G-6, but its even too slow for that (perhaps a poor example or a /trop one), for the official sepcs were 630 kph at 1,3ata for the G-6. For the G-2, the Finns measured 637 kph at alt with 1,3ata, but that was with a non-retractable tailwheel, whereas the Russians measured no less than 666 kph.. vs. this 620.
The original MerlinSpitV curves match or even exceed slightly the RAF figurs of 600kph max speed otoh.
Id guess the better cowling shape of the 605A also made a difference, I am not sure if theres such a big diffo between the Merlin 45 and the 605A when the latter runs at 1,3ata boost, perhaps at altitude.
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Originally posted by Angus
Nice doc.
Funny, it does not match with the text though.
"
The Spitfire's wing area was about 54 sq. ft. (5m²) greater than that of the Bf.109. The Messerschmitt was faster at low altitude, but at 11,000 ft. (3350 m) the speeds evened out"
And you can not see the ceiling either.
Probably someone made a simple mistake and took the 11000m, where the DB SpitV got faster, as ft.
btw, the 4 x .30cal, 2 x 20mm + amo comes very close to 300kg!
Wingarea and wingload dont mean liftload and dont take the drag into account!
Good high alt performers(and slowspeed planes in general) had and have a high wingaspectratio(P38, Ta152, Me109H, Spit with long wintips, most bombers, Me410, He219), rather than a big wingarea. Big wings = higher drag, high aspectratio = less induced drag + more effective wing.
Wings with a low aspectratio have advantages at highspeed(low level).
Greetings, Knegel
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Lower wingloading means lower A.o.A. at lower speeds - hence less drag.
But at higher speeds with less A.o.A. it means less and less.
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Hi,
you make the mistake to mix up wingload with liftload!
The needed AoA is of course related to the wingarea and weight, but also to the aspectratio, the airfoil and other wing-construction related features (the Spit-Wing for example was twisted to give a smooth stallbehaviour, but therfor never the complete wing had the optimal position into flightdirection, this decrease the max lift and increase the drag).
For the zero drag (CW0) the wingarea is a main factor. You be right that a higher aoa result in a higher drag in general, but drag= zero drag + induced drag and our planes, in the graph below, still fly around 330km/h IAS, when the DB-Spit overcome the Bf109G. So the test show that the DB-Spit, with 370kg weight-advantage, have less drag below around 330km/h.
How, do you think, this 3100kg 109G would perform with 370kg less weight in this comparison? It still would have a much greater wingload!
Wingload you only can use to compare planes with same wings!!
If you know that the wings of two planes are not twisted(washouts) and use a rather similar airfoil, you can use this formula to get a better approach to the liftload:
Weight / (Wingarea x aspectratio) = liftload
This explain why the P38, althought very heavy in wingload(242kg/m² 50% fuel), still was able to fly high and turn not to bad and why the Ta152H was a so much better turner and climber in relation to other 190´s, althought the wingload wasnt that smal at all(203kg/m², the heavy 109K4 had 207kg/m² but a much better powerload)!
Greetings, Knegel
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I am referring to the same wing with merely different loading.
So how is the mixup?
Still airfoil difference does not allow endless space either. The wings of the Spit and 109 perform very much in the same ballpark.
The only sensible way I have found to compare them is if the power is the same and the weight similar - then extrapolating climb times into Newtons. It won't be completely accurate - but it's a tremendous teaser all the same :D
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Hi,
as far as i can see you refer to the Spitfire wing in comparision to the Me109 wing(absolute different wings), here wingload isnt a reliable factor. At least the text, you did quote, did refer to the different wings.
If the power and weight would be the same, its relative easy to compare the wings, but we dont have this, the DB-Spit have a 370kg weightadvantage, while the normal Spit dont have the same power. Btw, to use climbtime as value to calculate the wingeffectivety, both planes need the same climbspeed, and best is to have climbresults with many different speeds, otherwise we only know the effectivety for thie one special speed!
Airfoil is not that important regarding lift(at least most WWII planes dont had that bad airfoils, therefor the different was rather smal), but the wingform is (Aspectratio, washouts, eliptical, trapeium, arrowed etc).
A wing which work good at slowspeed, can lose its advantage at higher speeds etc, all this make a comparison very difficult and wingload related arguments dont lead to anything, as long as we have different wings(Spit/Me109).
How, do you think, the 109G would perform in 11000m, with 370kg less weight??
Greetings, Knegel
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My mind was bent on the effect of decreasing or increasing winload of the Spitty in question, - the effect of the 300 kg's of armament you mention.
But cross comparing the two is always a bit fun, - especially if you are playing with the exact same power.
Then the variables are weight, airfoil, and drag basically, right?
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Hi,
ah rgr, i thought you was talking about DB-Spit vs 109G.
Yes, of course 300kg more weight on the DB-Spit would increase the induced drag, cause a higher aoa is needed to keep alt.
"But cross comparing the two is always a bit fun, - especially if you are playing with the exact same power.
Then the variables are weight, airfoil, and drag basically, right?"
Now you talk about 109/spit, right?
The basic variables are drag, weight, lift.
Weight is clear, but drag and lift are not that easy.
Lift get influenced by the airfoil(smal differents between modern WWII planes), wingarea (big differents), aspectratio (big differents) and other construction related aspects(washouts, slats, combatflaps, the last two dont count while steady flights).
The drag is splitted into zerodrag and induced drag, a subvariant are drag changings due to highspeed problems(shockwaves and other turbulences).
A increased Wingarea increase direct the lift, but in the same way the drag.
A increased aspectratio increase the lift with the factor phi(3,14) x aspectratio, and reduce the induced drag by 1/(3,14xaspectratio). On the other hand it increase the drag at highspeed by a to me unknown factor (shockwafes happen more early) and the structural construction is more difficult(long but smal wing = big leverage on a smal wingroot)
Washouts increase the drag and decrease the lift, but provide a more smooth stallbehaviour.
Slats(if open) increase the drag and the lift and the max AoA(wingarea increasement + a faster airflow over the wing), and give a smooth stallbehaviour, specialy if the slats work seperated. The production and maintance are more difficult.
Different Airfoils have more influences to the zero drag than to the lift.
Flaps are another story, their influences depends to their construction. In general they increase at least the drag.
Greetings, Knegel
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Originally posted by Angus
Lower wingloading means lower A.o.A. at lower speeds - hence less drag.
But at higher speeds with less A.o.A. it means less and less.
Keep in mind that at high altitudes, you actually have very low airspeeds (IAS) associated with whatever high true air speed figures.
Ie., the Rechlin test of the 109G-1 shows 640 kph TAS at 10km, but only 367 kph IAS.
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Yup Kuffie I know.
And Knegel - yepppers :aok