He 112 Development Potential

[GrauGeist]

The 109F with the DB 601N engine seems to be 15-20mph faster than a 109E (or T) using the same engine. Improvements in climb and turn are also quite noticeable if test figures are to be believed?

Part of the problem with some "what ifs" is how far do you go. The HE 112 was extensively modified from the early versions to the B series. About all they kept was the Jumo 210 engine and a cockpit in the middle of the plane (OK the landing gear?). The Fuselage was stretched and changed in construction. The vertical and rudder were changed. A whole new shorter span and changed plane form wing. The new wing was not only much smaller in area it changed form a 2 spar construction to a "single" spar with "auxiliary" spars in front and back (3 spar wing?). All three spars appear in cut away drawings to connect to fuselage.
A "similar" redo at some point in time after the B series could see the fuselage change in construction/size and another entirely new wing (keeping old landing gear?) eliminate any comprehensibility problems the old wing might have had.

But it would still be a He 112 right?

It is one thing to do such major changes at the prototype stage when each plane is almost hand built and little or no production tooling exists. It is quite another thing to make such extensive changes when multiple production lines exist in factories hundreds of miles apart. The change can be made but it requires a much larger investment in time and money (and lost production) to do it.

To be fair, however, look at the changes the Bf109 went through: A/B/C/D/E/F/G/K/T not including all the experimental knock-offs. The engines, the armament, the cowling, the canopy, the mainwing, the vert. stab. and even the tailwheel changed over the course of the Bf109's career.

Although they still had the same main-gear to the end.

 

[GregP]

I had never thought of it quite that way, Graugeist, but you gotta' love it. The part that is even funnier is they TRIED alternate landing gear and didn't incorporate it.

So they kept the landing gear and the windscreen ... two of the worst features on the plane! Perhaps they were also the cheapest to make?

 

[kool kitty89]

Fw-190 airframe was around early enough to compare with He112B. It was RLM insistence on BMW801 radial engine which delayed the program. The same RLM determination to use BMW801 engine would probably doom the He-112B. In order to compete Heinkel would need to design an airframe around the new engine.

The He 112B was already limited to the Jumo 210 for similar RLM and logistical reasons. The Jumo 211 was also initially in short supply, and the 210 was pressed into use for initial Bf 110 and Ju 87 production as well.

I do not know if it had the potential to still be competitive in 1945, but it could have been a good fighter in 1939 - 1941 for sure. It was almost certainly as good or better than the Hurricane, albeit in need of a better engine as-flown. The Hurricane might not have been all that great with a lesser engine than a Merlin, either. Perhaps the He 112 needed a DB 601 series engine to "wake up."

Against the 1939 Hurricane with fixed-pitch propeller, the 112B might have fared rather well in horizontal speed and especially roll, climb, and dive performance (roll and dive would likely remain an advantage regardless of propeller).

Still, given the cost it wouldn't make too much sense and either putting more Jumo powered 109s and 110s into training units or actually putting the Fw 187A into mass production would have made better use of the remaining supply of Jumo 210s in 1939/1940.

So development, while possible, might never have been practical from an engine availability standpoint. Still, they found sufficient engines for Bf 110's, so maybe there was some potential there.

Unless they could make the He 112 cheap enough to at least let performance/handling/cockpit characteristics weigh in as net advantages (especially with DB 601 production limiting volume more than airframe cost) I don't think it would be an attractive option.

As I said before, a different overall design ethic for the He 100 seems like the better option. They did already focus on greatly reducing parts count and manufacturing complexity/cost, but the He 100 was hardly an all around heavily rationalized aircraft. It had too much radical record setting speedster design ethic pressed into it to really make sense. Taking as many of the strengths of the He 112 design and boiling them down into something cheaper and faster to build and oriented around using either the DB 601 or Jumo 211 with at least SOME prototypes using completely conventional cooling systems from the start would have made far more sense. (the retractable radiator mechanism likely would have been favored initially, possibly for production as well, but eventually I'd imagine a more streamlined embedded fixed radiator would be used -retractable radiators themselves require a good deal of internal space as it is, so going the step further and orienting higher airflow, streamlined ducting into the radiator core embedded more or less as far as it would be when in fully retracted position would make more sense and likely be lighter -a variable geometry intake scoop might make more sense)

The limiting factor might be the wing. The HE 112 went through at least 3 different wings. I don't know what airfoil they wound up using on the last ones. It "looks" thick but that may be deceiving due to the long cord over most of the elliptical wing.

I wonder if this low aspect ratio 'thick' long chord wing (with thin airfoil) would be good for retaining relatively large internal stores capacity relative to area while the elliptical shape would make up for the lift:drag losses of the low aspect ratio. It very well may have been one of the areas that added to the 112's cost and complexity (and was abandoned in favored of a straight/tapered wing on the He 100) but it still seems like an interesting option. Heinkel's aspirations for a wooden wing might not have been cheaper in terms of labor either, but it should have been appealing in terms of materials. (assuming Heinkel could manage mass production of wooden components of the sort)

It's pretty much made up by this board. The only thing the real Fw 190 and a DB 601 powered "version" would really have in common would be the name/designation.

As it was the same could be said for the initial small Fw 190 V1 and the later prototypes, let alone the A-0 and A-1 production models. The initial V1 seems rather well suited to the 1100-1200 PS class engines of 1939, and honestly seems more likely to result in a production aircraft retaining more commonality to the V1 prototype than the A-1 ended up with. (also would have avoided the hang-ups related to inexperience with radial engines and both problems with placement and experimental cooling arrangements)

To be fair, however, look at the changes the Bf109 went through: A/B/C/D/E/F/G/K/T not including all the experimental knock-offs. The engines, the armament, the cowling, the canopy, the mainwing, the vert. stab. and even the tailwheel changed over the course of the Bf109's career.

Although they still had the same main-gear to the end.

Which, ironically, should have been one of the higher priority changes to be made at the beginning of the war, or even before that. Adapting wider-track gear with the transition from D to E, or more likely E to F would have been very significant for reducing overall attrition and number of operational aircraft. Between that and improvements to the canopy, there were a number of practical operational features that seem like they'd have been more logistically useful than the raw performance gains the 109F offered.

 

[Denniss]

The Bf 109F-4 with unrestricted 601E was actually in the 400mph range.

 

[GregP]

The F was probably the "best" Bf 109 of the family, if you believe the aces who flew them, that is.

I do.

 

[tomo pauk]

The Bf 109E-3 had a DB 601Aa that gave 1,175 HP at takeoff and 1,000 HP at 12,140 feet. Max speed at sea level was 290 mph. Max speed was 348 mph at 14,560 feet and initial rate of climb was 3,280 ft / min. Service ceiling was 34,450 ft.

The Bf 109F-4 had a DB 601E with 1,332 HP. Max speed at sea level was 325 mph. Max speed at 19,680 feet was 376 mph. Service ceiling was 38,048 feet.

The 109F-4 can do 390 mph even with a restricted DB 601E, and circa 410 mph with fully rated engine. Most of the Bf 109Es flew with DB 601A, the 601Aa was the export engine that still ended up in some 109s and 110s, mostly in Jabos, since it was a bit more powerful under 4.5 km. The '1000 HP at 12140 ft' for the 601Aa is way too low a figure, BTW.

If we take the E at 1,175 HP and do nothing but add the DB 601E engine with 1,350 HP, and drag doesn't change, I'd expect the new top speed to be 304 mph at sea level. To get 325 mph, the frontal area had to decrease by some 18 percent. That's a LOT, but believable since it happened.

A telling parameter is the E's top speed was at 14,560 feet and the F's top speed was at 19,680 feet. That tells me the supercharger wasn't the same or SOMETHING in the engine wasn't the same since it's best altitude went up by a third. At the E's best altitude it made about 1,000 HP. At the F's best altitude of 19,680 feet, the DB 601Aa made about 800 – 830 HP. The Bf 109F has to make 1030 HP one third higher to get 376 mph so, as I said above, a good deal of the extra performance came from engine improvements.

Supercharger was changed once with DB 601A, the 601N was also supposed to get a new S/C, but the main difference was that 601N and 601E were turning 200-300-400 RPM more than early 601A - this is where the gain in the rated height is achieved. Once the DB 601A was rated 1st for 2600 rpm (late 1940), and then 2800 rpm (mid/late 1941), it was better at high altitudes.
The refined ram air intake on the 109F also helped, so did the several times changed design of the prop.

If the E had done nothing but get the same engine, it would have had another almost 200 HP or so at 20,000 feet and the top speed would have been in the 365 mph range, which is only about 10 mph slower than an F. At the E's best height of 12,140 feet, the F could go 356 mph instead of 348 mph, which isn't all that big of a difference. But add up a few mph at the E's best altitude and a significant amount more HP at 20,000 feet and it makes a pretty significant difference.

The 109E was one cluttered aircraft, it performed well due to it's small size, reasonably thin wing and capable engine. The 376 mph speed for a 109F-4 is way under mark.

If anyone wants to propose different numbers, hey ... go for it.

I'm not making any wild claims here, I'm just proposing that the F's engine made up a good deal of the speed difference between the E and the F. The aerodynamic cleanup helped, but so did the engine change. Hopefully there's nothing unusual about better-performing planes getting a bit of help from many difference small changes. I'm pretty sure there was some cleanup that could be done on the He 112, too, but I still don't propose to estimate how much. It is, after all, a paper airplane that didn't get produced.

The aerodynamic cleanup helped a lot - 30 km/h (~20 mph) worth on same power?

 

[GrauGeist]

Originally Posted by GrauGeist
To be fair, however, look at the changes the Bf109 went through: A/B/C/D/E/F/G/K/T not including all the experimental knock-offs. The engines, the armament, the cowling, the canopy, the mainwing, the vert. stab. and even the tailwheel changed over the course of the Bf109's career.

Although they still had the same main-gear to the end.

Which, ironically, should have been one of the higher priority changes to be made at the beginning of the war, or even before that. Adapting wider-track gear with the transition from D to E, or more likely E to F would have been very significant for reducing overall attrition and number of operational aircraft. Between that and improvements to the canopy, there were a number of practical operational features that seem like they'd have been more logistically useful than the raw performance gains the 109F offered.

The maingear design by Messerschmitt was actually genius, as the gear's frame also contributed to the engine support, keeping the overall assembly light and easy to produce. It also allowed a huge advantage in transporting aircraft by land, performing maintenance/repair and keeping production time cost down. The Bf109's maingear design also found it's way into the He162, but was a little easier on the pilots because it was a tricycle configuration.

Trying to change the gear's track would have ended up affecting the entire production line, as it would involve the wing's structure as well as that of the engine mount all needing redesign.

Here's an interesting note on transporting a Bf109: "BF109 F-1 bis F-4 Flugzeughandbuch", May 1941.

 

[GregP]

Seems like the Bf 109F's top speed varies depending on who you speak with or read. I've seen actual data indicating from 373 mph max speed to claims of 415 mph, albeit without data.

I'll say it was decently faster than the E, but with a substantial boost due to HP. I'd estimate maybe half due to HP and half due to aerodynamic cleanup, give or take a bit. Whatever it went, it was one of the better variants.

After the F, it got heavier and more powerful and lost some of its great handling, but was still dangerous in the hands of a good pilot.

 

[Shortround6]

Greg, a big problem with evaluating the 109F's speeds is that it used two different engines and one or both were operated under restrictions for periods of time. The DB601N was actually an earlier engine than the DB601E. It was supposed to be good for 1175 PS not only at 0 meters altitude for 1 minute but 1175PS at 4900 meters for 1 minute. A few months after it's introduction in the summer of 1940 it was allowed to overspeed, 2800rpm vs 2600rpm at altitudes over 5500 meters for a bit better performance at altitude. It was the DB601N that was used in the 109F-0, F-1 and F-2. It had also been used a number of different 109E models, sometimes as a replacement engine as well as BF 110s and DO-215s.

The F-3 and F-4 got the DB601E engines but were originally restricted to 1200PS and finally allowed to use 1350PS Feb 1942.

Another point of confusion (at least for me) is that different sources seem to identify or rate the DB engines at different or nominal altitudes. The engines often had a higher output at an altitude between either take-off and the FTH at the altitude with the hydraulic coupling locked up (max rpm to supercharger).

 

[GregP]

Yeah, and it's sort of tough to find Bf 109F test data that include useful data all along the flight envelope. Many times I've seen data only to find the "top speed" was quoted, but no power setting, rpm, or height was quoted. Fairly useless data if you are interested in the aircraft, but I suppose better than no data at all.

I've also seen a lot of, shall we say, overly friendly top speeds quoted for the Bf 109. When 10+ sources say 378 and one says, 402, there are those who jump on the 402 with all the enthusiasm of a hungry badger. My own thoughts that run along engineering lines are to take maybe 6 - 10 readings from sources you consider relaible, throw out the high and the low, and average the rest. You're probably very close to reality. Another really good estimate is the root mean square.

If you have six readings, you square each one, add the squares, divide by the count (6) and take the square root. That is the value that is statistically the most likely if the six readings were correctly recorded. If one is WAY higher, throw it out as an outlier. Almost all engineering studies work that way or something very similar.

Obviously the six readings are aggregately faster than the slowest and slower than the fastest. You can defend several different estimates, but not if the fastest reading or slowest reading is selected as representative of the type.

 

[Shortround6]

From what I have read the Early 109Fs with the 601N were a good 20mph faster than an 109E using the same 601N engine, that at least equalizes the power and throws the difference on the airframe. I would disregard ALL references to 109F-3s and F-4s if trying to figure out what the aerodynamic modifications were worth.

 

[GregP]

Could be. I can't find much good data on any of the F models, but the web and books are full of data for the G-K-models.

What can you do except maybe learn to read German?

 

[kool kitty89]

Trying to change the gear's track would have ended up affecting the entire production line, as it would involve the wing's structure as well as that of the engine mount all needing redesign.

I'm aware of this and the transportation advantages, but the ground handling issues presented a serious problem for 109 operational logistics (especially with novice pilots). Granted, modifications to the tailwheel earlier on would have at least partially addressed this.

If a competing airframe would manage to address the problems while being competitively cost effective, that might have been better as well, but GregP's previous argument on the subject was that it should have been cheaper and faster to apply modifications to the 109 itself and retain at least a significant portion of existing tooling and manufacturing infrastructure.

There might have been other options than inward-retracting gear as well, like longer gear legs with wheels set at different angles. (this would require a wing redesign though)

 

[Denniss]

The low speed claimed for the F-4 originates from a british calculation based on F-2 performance upped to 1350 PS. They didn't know about the larger prop by this time + the engine of their F-2 was obviously not running properly as they either noted some supercharger problems or achieved this speed at a too low alt for this engine (can't remember exactly).
There's a test reports of 670 km/h (416 mph) at 6.3 km for the F-4 although it's not known where it has been recalc'd for compressibility effects and standard day/atmosphere.

 

[GregP]

Just have to find it ...

 

[SpicyJuan11]

It's pretty much made up by this board. The only thing the real Fw 190 and a DB 601 powered "version" would really have in common would be the name/designation.

Fw might have had a few paper sketches of a DB powered fighter in the late 30s but the DB engines available at the time did not have enough power to meet Kurt Tanks goal of a more rugged fighter than the Bf 109. A more rugged/sturdier fighter being heavier.

As it was the same could be said for the initial small Fw 190 V1 and the later prototypes, let alone the A-0 and A-1 production models. The initial V1 seems rather well suited to the 1100-1200 PS class engines of 1939, and honestly seems more likely to result in a production aircraft retaining more commonality to the V1 prototype than the A-1 ended up with. (also would have avoided the hang-ups related to inexperience with radial engines and both problems with placement and experimental cooling arrangements)

Are there any "best guesses" on what the performance of this bird would look like? Also, was there any large differences between the DB 601M and DB 601N?

 

[Shortround6]

Are there any "best guesses" on what the performance of this bird would look like? Also, was there any large differences between the DB 601M and DB 601N?

No guess except wishful thinking since even drawings are scarce to non-existent.

Kurt Tanks "philosophy" at the time was to build a rugged fighter that could stand up better to front line abuse. For instance the FW 190 was built to withstand landing impacts (vertical decent) of 4.5 meters per second/15 feet per second. This is supposed to about double what was common at the time and with the wide spread lading gear it was going to call for heavier landing gear and a stronger/heavier wing structure than a plane built for slower impact speeds. This is regardless of the wing area. The FW airframe was going to weigh more than the 109 airframe even if the FW was built to the same size. If they use the same engine we can reasonably guess that the FW aircraft will perform worse than the 109 unless the FW can reduce drag by enough to compensate for the extra weight.

 

[Ottobon]

The limiting factor might be the wing. The HE 112 went through at least 3 different wings. I don't know what airfoil they wound up using on the last ones. It "looks" thick but that may be deceiving due to the long cord over most of the elliptical wing.

One prototype with DB 601 engine was supposed to hit 354mph which is about the same as a Bf 109E with the same engine ( or a bit better?). The question is did the He 112 have enough stretch left to match the 109F without another major redo?

Yeah that was the He 112 V10 with DB 601Aa (also V11 with DB 601A)

Very VERY little data about it but "German Aircraft of the Second World War" makes a mention of it

https://books.google.com/books?id=AvTgjHwl1sMC&printsec=frontcover#v=onepage&q&f=false (page 138 and 139)

It says that it was intended for the He 112E (E for export apparently) and as you said hit 354mph and had a range of 715 miles. Apparently it was the model of He 112 that was sold to Japan. I think if such a plane was built in time for BoB it could of been useful to some degree but probably not worth taking resources away from the BF 109.



Completely off topic but apparently there was also a Fiat CR.42 that was also fitted with a DB 601 , sounds like a hoot

 

[GrauGeist]

In regards to the "rare" inline powered Fw190 before the D series:
V13 SK+JS (WkNmr 0036) fitted with DB603A-0 (Fw190C prototype) - first flew early 1942
V15 CF+OV (WkNmr 0037 fitted with DB603A-2, external oil cooler under fuselage, enlarged wings - first flew 10 May 1942
V17 CF+OX (WkNmr 0039) fitted with Jumo213 - first flew 26 September 1942
V18 CF+OY (WkNmr 0040) fitted with TK 11 exhaust turbine, GM1 and DB603A-1 - first flew 20 December 1943
V21 TI+IH (WkNmr 0043) fitted first with Jumo213, replaced with DB603L - first flew 13 April 1943
V25 GH+KO (WkNmr 0050) fitted with Jumo213C, Mk103 engine cannon, 2 Mk108 canon - first flew June 1943
V26 GH+KP (WkNmr 0051) fitted with DB603A-1, pressurized cockpit - first flew June 1943
V29 GH+KS (WkNmr 0054) fitted with DB603S-1, enlarged wings - first flew March 1943
V31 GH+KU (WkNmr 0056) fitted with DB603S-1, enlarged wings: became Ta152H-0 - first flew February 1943
V32 GH+KV (WkNmr 0057) fitted with DB603S-1, MG151 in wing roots - first flew 11 November 1943
V33 GH+KW (WkNmr 0058) fitted with DB603S-1 - first flew April 1943

This is not a complete list, but it does cover the C prototypes and pre-D types and illustrates that the inline powered Fw190 was not as rare as some may think.

Here's a few photos of the ones listed above:
Fw190 V13

Fw190 V16

Fw190 V18

Fw190 V32

 

[GregP]

Great post, Graugeist.