Best radial fighter of '42

[Vincenzo]

for the Macchi the difference was large, but if i not wrong the Breda production it's from '40, summer?, so obv. was different from a '39 aircraft (ever if the tested plane was not the prototype)
weight 1778-2208
speed 502 km/h at 5 km, 493km/h at 6km
climb at 4 km in 3'54'' at 6km in 6'29''
takeoff 225 meters landing 338 meters

 

[Vincenzo]

Gatt have you info on pressure boost? (talking on "italian" engines on italian fighters)

io ho letto da qualche parte, al momento non ricordo dove ma penso su qualche articolo in qualche rivista di settore, che c'era al possibilità di aumentare la pressione del flusso carburante, se non ho capito male, e nel caos dell motore fiat A 74 era chiamata + 100 (nome dovuto al fatto che si aumentava di 100 m di mercurio la pressione forse a cmq)
ciao e grazie ancora per l'aiuto

 

[Gatt]

Well, generally speaking, the Fiat A74 RC38 was used with a boost pressure of about 790mm Hg (about 1.1ata and 2.400rpm). However, the pilot could use the +100 option for a short time pushing the boost at 890mm Hg (about 1,2ata and 2.520rpm).

According to the C.200 manual the +100 was allowed for short take-offs but forbidden during the climb to altitudes. We dont know for how long time the italian pilots used the +100 in combat.

 

[Vincenzo]

I saw the different power setting for C.200 e G.50 in the your posted manuals.

ho notato i giri differenti per il macchi e il fiat, sembrerebbe che il macchi era limitato a 2400 giri ma il fiat andava a 2520, forse c'erano problemi di robustezza dell'installazione o dell'aereo?

mi dai un anteprima dei dati dal manuale del reggiane? , vabbo lo ammetto era solo un tentativo per ricordarti che sto/stiamo ancora in attesa della scansione dal manuale

ciao

 

[Gatt]

Nope, the A74 mounted on the C.200 had no limitation. Max allowed settinges were the same, i.e. 2520rpm at 890mm Hg.

Later I'll post the Re.2000 manual pages about performances.

 

[Vincenzo]

Nope, the A74 mounted on the C.200 had no limitation. Max allowed settinges were the same, i.e. 2520rpm at 890mm Hg.

Saw the macchi test on climb at 2400/1' and on speed at 2430-70/1' and fiat manual speed on 2520/1' how you explain the difference? trouble in test or other?

 

[Vincenzo]

that FAF A-4s had their Cyclones changed to P W Twin Wasps by late 1941 and looking both imports and also the total losses in 1941 , FAF used A-1s, A-2s, A-3s and A-6s in 1942.

I'm not sure of understand, so FAF don't used A-4 (obv. reengined) in '42?

Please can give info on the FAF speed test on Fiat G.50? with info on power setting and weights if possible

 

[Gatt]

Saw the macchi test on climb at 2400/1' and on speed at 2430-70/1' and fiat manual speed on 2520/1' how you explain the difference? trouble in test or other?

Aircraft are seldom or never tested at their max engine settings. They usually are tested at their continous allowed engine setting. For the A74 it is 2.400rpm at 790mm Hg.

 

[Juha]

Hello Vincenzo
yes, FAF didn't have Cyclone engined Hawk75As after late 1941, all were re-engined by then.

FAF, the best G.50 speed recorded was flown by FA-15 on 16.6.42,430km/h boost 790mmHg, worst test flown max speed at FTH was 403 km/h, the size of the airscrew and how well pitch was correct. Speed at sealevel usually ca. 380km/h with 890 mmHg. Only observations on weights is the general observation that empty weight 1920kg, max 2350 kg.

Juha

 

[Vincenzo]

Hello Vincenzo
yes, FAF didn't have Cyclone engined Hawk75As after late 1941, all were re-engined by then.

FAF, the best G.50 speed recorded was flown by FA-15 on 16.6.42,430km/h boost 790mmHg, worst test flown max speed at FTH was 403 km/h, the size of the airscrew and how well pitch was correct. Speed at sealevel usually ca. 380km/h with 890 mmHg. Only observations on weights is the general observation that empty weight 1920kg, max 2350 kg.

Juha

thanks for the data on FAF's G.50

for the first question you don't understand my question, or best you don't understand my badest english, the A-4 airframes (with the P&W) were used in '42? (i know with the P&W they are same of older variant my i'm curious)

p.s. data on rpm of fiat engine?

 

[Juha]

Hello Vincenzo
yes, A-4 airframes with P&W engines were in use in 42.
On Fiat, Max rpm 2520rpm

 

[Elvis]

Hey Henning,

Sorry I've taken so long to get back to you.
I recently moved and only have 1 hour a day for "computer time".
Thanks for clarifying the differences in the turn rates.
IIRC, the figure I quoted was for a certain altitude and a certain speed (1000M @200kts., I think), so I guess what my figure is showing is just howtight of a turn that plane could make.
Yours, if I understand correctly, seems to be more of an "outright speed" figure. I.e., the tightest turn the plane could make, at the highest possible speed, given a certain altitude.

Elvis

P.S. Nice new look. I don't recognize the old place!

Hi Elvis,

>In post #73, Ju Ha wrote the following as part of that post...

>That works out to 25.7+ deg./sec.

>Why the differences in those figures compared to yours?

I guess that the higher figure is for a combat turn that sustains altitude, but not speed.

I calculate a sustained turn speed of about 240 km/h TAS, while 350 km/h IAS (calibrated, I assume) works out to 386 km/h TAS. At that speed, the F2A according to my calculations is capable of a 40 degrees per second turn, pulling 7.7 G and decelerating with 6.6 m/s^2. (The deceleration of course reduces G rate, turn rate and further deceleration, so I'd say like my calculations are in the same ballpart for a decelerating turn as those Juha quoted.)

In my opinion, the figure of 350 km/h is what we'd consider "corner speed" in modern technology - the speed at which the F2A can generate the highest instantaneous Gs that can be usefully employed to combat, limited by airframe strength or by the pilot's ability to resist G forces. That's probably the reason it's listed for 180 degrees of turn - if attacked by an enemy from astern, you could make such a turn from corner speed to spoil his attack, and after 180 degrees you'd probably be facing him head-on (depending on the timing of the turn, of course).

A sustained turn at 350 km/h IAS would be much tamer and have a much wider radius - I calculate 14.5 degrees per second compared to the 23.3 degrees per second at 240 km/h TAS for highest sustained turn rate.

Regards,

Henning (HoHun)

 

[Gatt]

I saw the different power setting for C.200 e G.50 in the your posted manuals.

ho notato i giri differenti per il macchi e il fiat, sembrerebbe che il macchi era limitato a 2400 giri ma il fiat andava a 2520, forse c'erano problemi di robustezza dell'installazione o dell'aereo?

mi dai un anteprima dei dati dal manuale del reggiane? , vabbo lo ammetto era solo un tentativo per ricordarti che sto/stiamo ancora in attesa della scansione dal manuale

ciao

Here are some pages from the english version of the Re.2000 flight and manteinance manual:

 

[Elvis]

Nice docs, Gatt.
Thanks for posting those.

Someone recently asked about P&W Twin Wasp powerplant for FAF.
I think all of the Twin Wasps that were used by other nations was the "STWC3-CG" version (I think that's how it goes), which made approximately 1050 HP.
I believe it's American equivelent was the R-1830-90.
The American version made 1200HP and I believe the difference in power was due to the lower octane rating of the fuel used by other nations.
I just viewed a site on the Swedish J-22 and the author there believes that if the same high octane fuel was used for that engine, that the American's used, the powerplant would've made 1200HP.
He even has some graphs that depict the difference in performance that the higher octane fuel would make.



Elvis

 

[Vincenzo]

Two questions

for aerodyamical experts can the open canopy of finnish G.50 down the speed from 480 to 403/430 km/h?

for italian experts why in the G.50 was available 2520 rpm on flight (as FAF test and italian manual) and for C.200 not (was available only for takeoff)?

thanks

 

[Vincenzo]

Two questions

for aerodyamical experts can the open canopy of finnish G.50 down the speed from 480 to 403/430 km/h?

for italian experts why in the G.50 was available 2520 rpm on flight (as FAF test and italian manual) and for C.200 not (was available only for takeoff)?

thanks

 

[Gatt]

Two questions

for aerodyamical experts can the open canopy of finnish G.50 down the speed from 480 to 403/430 km/h?

for italian experts why in the G.50 was available 2520 rpm on flight (as FAF test and italian manual) and for C.200 not (was available only for takeoff)?

thanks

Vincenzo, the limitation of 2.520 and 890mm Hg was valid for the G.50 as well. Actually, for all the fighters with the A74.
You could fly at 2.500rpm but not exceeding the 790mm Hg boost limit and for a limited time.
From the G.50 flight operating instructions:

 

[Vincenzo]

I'm sorry for not use of official language. if somebody can transtlate i'm thank him.

allora il manuale del G.50 e i test finlandesi danno la velocità massima dello stesso a 2520/1', il manuale del C.200 e i test italiani a 2400/1'. Dato per scontato che le potenze massime, di emergenza, sono ottenibili per periodi limitati (1'/5' comunemente), dato poi che hai riferito che il manuale del C.200 specifica si usare i 2520/1' solo per ottenere decolli corti, a mio modesto parere, date le informazioni sopra riportate, c'è una diversità fra i due caccia, che fa si tra l'altro che le due velocità massime non sono direttamente confrontabili, in quanto il macchi può mantenere la sua per un periodo più lungo.

 

[LWulf]

I'm sorry for not use of official language. if somebody can transtlate i'm thank him.

allora il manuale del G.50 e i test finlandesi danno la velocità massima dello stesso a 2520/1', il manuale del C.200 e i test italiani a 2400/1'. Dato per scontato che le potenze massime, di emergenza, sono ottenibili per periodi limitati (1'/5' comunemente), dato poi che hai riferito che il manuale del C.200 specifica si usare i 2520/1' solo per ottenere decolli corti, a mio modesto parere, date le informazioni sopra riportate, c'è una diversità fra i due caccia, che fa si tra l'altro che le due velocità massime non sono direttamente confrontabili, in quanto il macchi può mantenere la sua per un periodo più lungo.

I've tried to translate the best I could with my rusty Italian and poor English.

So, the manual of the G.50 and the Finnish test give a maximum speed with the 2520 rpm power setting. The manual of the MC.200 and the Italian tests show 2400 rpm. Of course the maximum power, for emergencies, is usable only for a limited time (1 to 5 minutes usually), as you've noted for the MC.200 manual where it says to use 2520 rpm power setting only for shorter take offs, which imho, given the informations I've already mentioned, there seems to be a difference between the Fiat and Macchi fighter. Given this the top speeds of these two fighters are not directly comparable, since the Macchi can hold its max speed for a longer period of time.

 

[Gatt]

Well, my english must be rusty as well .... what I mean is that ALL the A74 engined fighters could get 2.520rpm. However boost pressure could not be pushed above 790mm Hg. This was valid for continuous climb and high speed level flight.

2520rpm at 890mm Hg of boost pressure (the so called "+100") were used only for short take offs, and probably only for short time in combat (IMO).