"Zerstörer" specification, but as an 1-engined fighter

[don4331]

I think you are optimistic on Bf.113 Performance:

Airplane	Bf.109E-0	Bf.110C-3	Hurricane Mk.1
Empty weight	4,430lbs
Loaded weight	5,520lbs
Wing area	177ft^2
Range	350 mi	560 mi
Fuel	88 Imp gal	279 Imp gal	87 Octane
Top speed	348 mph	334 mph	314 mph
Cruiser	236 mph	224 mph	212 mph

I didn't complete some of the cells as they aren't critical; Hurricane performance is for fixed pitch propeller on 87 octane - what the Luftwaffe encountered during the BoF. As may be seen, both Luftwaffe fighters enjoy a substantial performance advantage.

For the BoB, the Hurricane has been upgraded with CS propeller and 100 octane fuel - performance is very close to Bf.110 (individual aircraft are probably better/worse)

The Bf.109 basically gets 4 mpg whether internal or internal + drop tank. So, to fly 560 miles, it needs 140 Imp gal. For the Bf.113 with annual radiator, assuming the same 66 Imp gal fuselage tank of the Bf.109G-12, you need 74 gal in wings. There is space in the wings for 37 gal/side between main and rear spar but:

The Bf.113 is carrying navigator/radio operator/rear gunner (requirement of Zerstörer specification).​

tomo pauk also specified the same 2 - MG FF and 4 - MF 17 from Bf.110; upgrading from MG 17 to MG FF added 100 lbs from Bf.109E-0 to Bf.109E-3​

The end result by my napkin calculations is the Bf.113 is 700lbs heavier; so it needs Wing area increase 30% over Bf.109 to maintain equal wing loading. Cube root suggests ~10% increase in drag. So, now we need 154 gal (700 litres); 44gal per side for same range.​

Airplane	Hurricane Mk.1	Bf.113
Empty weight		5,130 lbs
Loaded weight		7,388 lbs
Wing area		230 ft^2
Range		560 mi
Fuel	100 Octane	154 Imp gal
Top speed	329 mph	313 mph
Cruise	212 mph	212 mph

The Bf.113 has performance equal to BoF Hurricane and inferior to BoB uprated ones.

If Bf.110 struggled in BoB, the Bf.113 is going to struggle in BoF and going to be in real trouble in BoB. And it's going to be too slow and too short ranged to be a decent night fighter (Ju.88 and He.219 had much greater range and so were better night fighters for average pilot)

 

[tomo pauk]

I think you are optimistic on Bf.113 Performance:
I didn't complete some of the cells as they aren't critical; Hurricane performance is for fixed pitch propeller on 87 octane - what the Luftwaffe encountered during the BoF. As may be seen, both Luftwaffe fighters enjoy a substantial performance advantage.

For the BoB, the Hurricane has been upgraded with CS propeller and 100 octane fuel - performance is very close to Bf.110 (individual aircraft are probably better/worse)

Hurricane was doing just under 320 mph with the better prop. 100 oct fuel will not matter above ~16000 ft.
I think I'm realistic of the 113 performance, my ballpark was the D4Y1, that was good for 330 mph on the very similar engine as what the LW fighters used in 1939. Note that the 113 I was suggesting is a bit smaller fighter than the Hurricane, with a thinner wing and with better radiator set-up and exhausts. So if anything, I was being conservative.
Or, a tad slower Re.2001 or P-40B/C.

The Bf.109 basically gets 4 mpg whether internal or internal + drop tank. So, to fly 560 miles, it needs 140 Imp gal. For the Bf.113 with annual radiator, assuming the same 66 Imp gal fuselage tank of the Bf.109G-12, you need 74 gal in wings. There is space in the wings for 37 gal/side between main and rear spar but:
The Bf.113 is carrying navigator/radio operator/rear gunner (requirement of Zerstörer specification).

I've noted several times now that fuel tank(s) should be under the cockpit (again, cue the Judy, just with the thinner belly that is not a bomb bay but a place for tanks). Fuselage was probably the best place for the fuel tanks for the fighters, especially once self-sealing was in play, since the % lost due to the thicker material was the lowest.
The much bigger wings of the 113 (when compared with Bf 109) should allow for the growth of fuel tankage for the later day.

Bf 109E was already a draggy aircraft, let alone with a drop tank.

tomo pauk also specified the same 2 - MG FF and 4 - MF 17 from Bf.110; upgrading from MG 17 to MG FF added 100 lbs from Bf.109E-0 to Bf.109E-3The end result by my napkin calculations is the Bf.113 is 700lbs heavier; so it needs Wing area increase 30% over Bf.109 to maintain equal wing loading. Cube root suggests ~10% increase in drag. So, now we need 154 gal (700 litres); 44gal per side for same range.

See Re.2001. It was getting 1040 km at 375 km/h, or 890 km at 440 km/h. All for 400 kg of fuel (~530L).
Or P-40B - with 120 gals (~454L), it was supposed to do 620 miles (~1000 km) on 'operating speed' of 306 mph.

I've suggested 600L of fuel for the 113.

The Bf.113 has performance equal to BoF Hurricane and inferior to BoB uprated ones.

If Bf.110 struggled in BoB, the Bf.113 is going to struggle in BoF and going to be in real trouble in BoB. And it's going to be too slow and too short ranged to be a decent night fighter (Ju.88 and He.219 had much greater range and so were better night fighters for average pilot)

The 113 can also be uprated, and by installing the DB 601N engines, as well as by increasing the revs on the DB 601A. It will be far easier to up-engine the 113 fleet than the historical 110 fleet, by the simple virtue of needing less engines.
Some of the shortcoings of the 110 will also not be here now, like the big size (easier to spot it and act accordingly; easier to hit it), less of the blind spots since there is no nacelles and the wing is smaller, better rate of roll (again since there is no big weight of the engines away from the centreline, and the wing is much smaller).
One of the resons the Bf 110 was not all what it was expected was also that there was just a small number of them, so once the Bf 109s needed to head home, the LR force was badly outnumbered. The 113s main advantage IMO is that they can solve the problem of low numbers of the LR fighters, so that problem of being outnumbered is much smaller.

 

[Shortround6]

The problem is you want this thing to be fighter or at least fighter like?
The D4Y1 was about 2440kg empty and 3650kg normal loaded.
It was fast, It couldn't climb for crap. One source say 3000 meters in 5 min 14 sec.
The D4Y2 got that down to 4 min 36 sec.
Adjust weights as appropriate.
Normal Bomb load was 310kg (one 250kg and two 30kg)
Max weight was 4250kg and max bomb load was 560kg (one 500 and two 30kg)
The plane was supposed to carry two 330 liter external tanks but those showed up late (?) and the combination with bombs is questionable ( late service use of D4Y1s for recon)

Granted the Bf 110 was not much of a dog fighter but it was supposed to 'Boom and Zoom" the D4Y1 can "boom" but it can't Zoom.

 

[wuzak]

The Rolls Royce Vulture supposedly was two Peregrine engines stuck together. They probably could have got it working if they had kept at it, but other things were working and needed more development to get maximum performance. Everybody's resources were finite.

Slapping two Peregrines together might have been the original idea behind the Vulture, but then it quickly turned out it wasn't so easy. IIRC they needed bigger bore spacing for the Vulture, so they needed new cylinder and head castings anyway. And so on.

It is often said that the Vulture was two Peregrines bolted together, but it isn't true.

Firstly, as noted by z42, the bore spacing was wider - almost the same as the Merlin's in fact.

Secondly, there were no Peregrines around to bolt together when the design of the Vulture was started.

The Vulture was first run in 1937, the Peregrine in 1938.

 

[don4331]

Hurricane was doing just under 320 mph with the better prop. 100 oct fuel will not matter above ~16000 ft.
I think I'm realistic of the 113 performance, my ballpark was the D4Y1, that was good for 330 mph on the very similar engine as what the LW fighters used in 1939. Note that the 113 I was suggesting is a bit smaller fighter than the Hurricane, with a thinner wing and with better radiator set-up and exhausts. So if anything, I was being conservative.
Or, a tad slower Re.2001 or P-40B/C.

But the Aichi AE1A Atsuta 21 which the D4Y1 is more equivalent to the DB601N and not what is found in majority of B.f110s; Your Bf.113A needs to fly with Jumo 210D engine initially as the DB601 wasn't "certified" for single engine planes as it wasn't reliable enough; heck it wasn't reliable enough for twins and the Bf.110B had to revert to Jumo 210s. The Bf.113 needs to fly in '37, not '41.

I've noted several times now that fuel tank(s) should be under the cockpit (again, cue the Judy, just with the thinner belly that is not a bomb bay but a place for tanks). Fuselage was probably the best place for the fuel tanks for the fighters, especially once self-sealing was in play, since the % lost due to the thicker material was the lowest.
The much bigger wings of the 113 (when compared with Bf 109) should allow for the growth of fuel tankage for the later day.

Bf 109E was already a draggy aircraft, let alone with a drop tank.

But your Bf.113 is being designed at same time and by same individuals (more/less) as the Bf.109 - so it is going to be just as draggy. The Judy is a 4 year later aircraft; state of the art had moved a long ways in that time.

See Re.2001. It was getting 1040 km at 375 km/h, or 890 km at 440 km/h. All for 400 kg of fuel (~530L).
Or P-40B - with 120 gals (~454L), it was supposed to do 620 miles (~1000 km) on 'operating speed' of 306 mph.

I've suggested 600L of fuel for the 113.

The 113 can also be uprated, and by installing the DB 601N engines, as well as by increasing the revs on the DB 601A. It will be far easier to up-engine the 113 fleet than the historical 110 fleet, by the simple virtue of needing less engines.
Some of the shortcomings of the 110 will also not be here now, like the big size (easier to spot it and act accordingly; easier to hit it), less of the blind spots since there is no nacelles and the wing is smaller, better rate of roll (again since there is no big weight of the engines away from the center line, and the wing is much smaller).
One of the reasons the Bf 110 was not all what it was expected was also that there was just a small number of them, so once the Bf 109s needed to head home, the LR force was badly outnumbered. The 113s main advantage IMO is that they can solve the problem of low numbers of the LR fighters, so that problem of being outnumbered is much smaller.

If you have built 2X Bf.113s they are just as hard to completely upgrade because you have to upgrade twice as many.

The challenge for the Luftwaffe fighters is they are escorting the bombers at cruise speed - engines/fuel supply can't afford full power the entire way. So, the fighters need to increase speed by ~90mph - which takes time...during which they are sitting ducks for the RAF. Göering's tying the fighters close to the bombers, only makes this worse - you don't even have an altitude advantage.

 

[tomo pauk]

But the Aichi AE1A Atsuta 21 which the D4Y1 is more equivalent to the DB601N and not what is found in majority of B.f110s; Your Bf.113A needs to fly with Jumo 210D engine initially as the DB601 wasn't "certified" for single engine planes as it wasn't reliable enough; heck it wasn't reliable enough for twins and the Bf.110B had to revert to Jumo 210s. The Bf.113 needs to fly in '37, not '41.

Japanese (Bunrin Do book about the Judy) says that Atstuta 21 was good for 965 PS at 4450m. The Judy entry in the TAIC manual says 955 HP at 14800 ft.
That means that the DB 601A is a tad better at the altitude of interest.
I have no problems that initial 113s fly with Jumo 210, after all the big He 118 and Ju 87 both flew with RR Kestrel as prototypes. Switch to the DB 600 family as per historically, ie. early 1939.
BF 110B probably went with Jumo 210 engines because there was not enough of the DB 600 series engines, that were used on the He 111s and Bf 109s; the grand total of 88 of the 110Bs were made.

But your Bf.113 is being designed at same time and by same individuals (more/less) as the Bf.109 - so it is going to be just as draggy. The Judy is a 4 year later aircraft; state of the art had moved a long ways in that time.

One radiator that is in front of the fuselage should be less draggy than the two hanging out under the wing. As with the Bf 110, there is no need for the struts in the horizontal tail. Historical Bf 110 flew one year after the 109, so there is some time to improve a tad when it is about the fighters by MTT.

BTW - I have no problems that Heinkel designs the 113, as you can see by my posts.

If you have built 2X Bf.113s they are just as hard to completely upgrade because you have to upgrade twice as many.

I will probably not have the 2x of the 113s, but perhaps about 1.75x? Upgrading, say, 300 of them during the BoB is still a better math than upgrading 180 of the 110s.

The challenge for the Luftwaffe fighters is they are escorting the bombers at cruise speed - engines/fuel supply can't afford full power the entire way. So, the fighters need to increase speed by ~90mph - which takes time...during which they are sitting ducks for the RAF. Göering's tying the fighters close to the bombers, only makes this worse - you don't even have an altitude advantage.

This is where the bigger number of the LR fighters can come in handy - devote perhaps 60% of them for the close escort, and 40% for Freijagd.

 

[tomo pauk]

FWIW, the rough comparison between the prototype of the He 112 (up; note the upright V12, ie. RR Kestrel) and the definitive He 112B version (down). Hopefully I've not messed too much with the scale.
Note how much the wing was smaller on the 112B; there was also an in-between wing, both time-wise and size-wise, as Heinkel was trying to tailor the size of the aircraft to be better suited to the indifferent Jumo 210 engines. Also note the wheel well covers, a thing that went away as the He 112 was changing, but it might've come inn handy for the -113.
Obviously, our brave new Zerstoerer will need the wing that is much closer to the area and span of the original He 112 wing that the prototype had.

 

[Zmauky]

Speaking of He 112, do we know the airfoil? The only thing I found was "Heinkel". And where you can buy, borrow or steal good blueprints, especially for A variants.

 

[don4331]

Speaking of He 112, do we know the airfoil? The only thing I found was "Heinkel". And where you can buy, borrow or steal good blueprints, especially for A variants.

Aren't there a least 2 very different airfoils? That the V1 has a much thicker airfoil than the V2. And V4 has yet another wing redesign??

 

[tomo pauk]

Speaking of He 112, do we know the airfoil? The only thing I found was "Heinkel". And where you can buy, borrow or steal good blueprints, especially for A variants.

Even the probably the best book about the He 112 is lacking wrt. blueprints.
Here is the side elevation cutaway of the He 112A, FWIW:



Quick and dirty measurement shows the ttc of some 18% at root, and 17% on the lowest end of the inverted gull wing.

 

[don4331]

Even the probably the best book about the He 112 is lacking wrt. blueprints.
Here is the side elevation cutaway of the He 112A, FWIW:

View attachment 801502

Quick and dirty measurement shows the ttc of some 18% at root, and 17% on the lowest end of the inverted gull wing.

Aeroweanie has Heinkel He 112 root Heinkel 16.5%, tip Heinkel 9% on his site (I don't know if that is pre-production, A series or B...

Heinkel He 70 Blitz had used: Root: Goettingen 600 (13%); Tip: Goettingen 600 (10.2%); I wonder how similar they are..

 

[Zmauky]

Thank you for the side view, the best I've seen so far. For the B variant I have the blueprints from the W.M.23 Ezüst Nyíl but they are in cad and have wing sections. Although it seems to me from the photos that the wings between the A and B variants are not only different in plan but also in airfoil ?

 

[Aeroweanie]

Thank you for the side view, the best I've seen so far. For the B variant I have the blueprints from the W.M.23 Ezüst Nyíl but they are in cad and have wing sections. Although it seems to me from the photos that the wings between the A and B variants are not only different in plan but also in airfoil ?

Can you post images of the airfoils in the CAD? I'm curious to see the airfoils in more detail.

 

[Zmauky]

Can you post images of the airfoils in the CAD? I'm curious to see the airfoils in more det

PM send (I hope) if it's not working please contact me.

 

[marathag]

BMW 801? Though it's hard to imagine the little Fw-190's engine in something the size of the P-47.

Handy for size comparisons